Effects of temperature, pressure, and carrier gas on the cracking of coal tar over a char-dolomite mixtures and calcined dolomite in a fixed-bed reactor

DOE Office of Scientific and Technical Information (OSTI.GOV)

Seshadri, K.; Shamsi, A.

1998-10-01

A distillation fraction of a coal-derived liquid (tar) was cracked over a char-dolomite mixture, calcined dolomite, and silicon carbide in a fixed-bed reactor. The char-dolomite mixture (FWC) was produced from Pittsburgh No. 8 coal and dolomite in a Foster Wheeler carbonizer. The experiments were conducted under nitrogen and simulated coal gas (SCG), which was a mixture of CO, CO{sub 2}, H{sub 2}S, CH{sub 4}, N{sub 2}, and steam, at 1 and 17 atm. The conversion over these materials under nitrogen was much higher at 17 atm than at 1 atm. At higher pressures, tar molecules were trapped in the poresmore » of the bed material and underwent secondary reactions, resulting in the formation of excess char. However, when nitrogen was replaced by SCG, the reactions that induce char formation were suppressed, thus increasing the yield of gaseous products. The analysis of the gaseous products and the spent bed materials for organic and inorganic carbons suggested that the product distribution can be altered by changing the carrier gas, temperature, and pressure.« less

Process for the manufacture of an attrition resistant sorbent used for gas desulfurization

DOEpatents

Venkataramani, Venkat S.; Ayala, Raul E.

2003-09-16

This process produces a sorbent for use in desulfurization of coal gas. A zinc titanate compound and a metal oxide are mixed by milling the compounds in an aqueous medium, the resulting mixture is dried and then calcined, crushed, sleved and formed into pellets for use in a moving-bed reactor. Metal oxides suitable for use as an additive in this process include: magnesium oxide, magnesium oxide plus molybdenum oxide, calcium oxide, yttrium oxide, hafnium oxide, zirconium oxide, cupric oxide, and tin oxide. The resulting sorbent has a percentage of the original zinc or titanium ions substituted for the oxide metal of the chosen additive.

Carbon Cloth Supported Nano-Mg(OH)2 for the Enrichment and Recovery of Rare Earth Element Eu(III) From Aqueous Solution.

PubMed

Li, Yinong; Tian, Chen; Liu, Weizhen; Xu, Si; Xu, Yunyun; Cui, Rongxin; Lin, Zhang

2018-01-01

Nano-Mg(OH) 2 is attracting great attention as adsorbent for pre-concentration and recovery of rare earth elements (REEs) from low-concentration solution, due to its superior removal efficiency for REEs and environmental friendliness. However, the nanoparticles also cause some severe problems during application, including aggregation, blockage in fixed-bed column, as well as the difficulties in separation and reuse. Herein, in order to avoid the mentioned problems, a carbon cloth (CC) supported nano-Mg(OH) 2 (nano-Mg(OH) 2 @CC) was synthesized by electrodeposition. The X-ray diffraction and scanning electron microscopy analysis demonstrated that the interlaced nano-sheet of Mg(OH) 2 grew firmly and uniformly on the surface of carbon cloth fibers. Batch adsorption experiments of Eu(III) indicated that the nano-Mg(OH) 2 @CC composite maintained the excellent adsorption performance of nano-Mg(OH) 2 toward Eu(III). After adsorption, the Eu containing composite was calcined under nitrogen atmosphere. The content of Eu 2 O 3 in the calcined material was as high as 99.66%. Fixed-bed column experiments indicated that no blockage for Mg(OH) 2 @CC composite was observed during the treatment, while the complete blockage of occurred to nano-Mg(OH) 2 at an effluent volume of 240 mL. Moreover, the removal efficiency of Mg(OH) 2 @CC was still higher than 90% until 4,200 mL of effluent volume. This work provides a promising method for feasible application of nanoadsorbents in fixed-bed process to recycle low-concentration REEs from wastewater.

Carbon Cloth Supported Nano-Mg(OH)2 for the Enrichment and Recovery of Rare Earth Element Eu(III) from Aqueous Solution

NASA Astrophysics Data System (ADS)

Li, Yinong; Tian, Chen; Liu, Weizhen; Xu, Si; Xu, Yunyun; Cui, Rongxin; Lin, Zhang

2018-04-01

Nano-Mg(OH)2 is attracting great attention as adsorbent for pre-concentration and recovery of rare earth elements (REEs) from low-concentration solution, due to its superior removal efficiency for REEs and environmental friendliness. However, the nanoparticles also cause some severe problems during application, including aggregation, blockage in fixed-bed column, as well as the difficulties in separation and reuse. Herein, in order to avoid the mentioned problems, a carbon cloth (CC) supported nano-Mg(OH)2 (nano-Mg(OH)2@CC) was synthesized by electrodeposition. The X-ray diffraction and scanning electron microscopy analysis demonstrated that the interlaced nano-sheet of Mg(OH)2 grew firmly and uniformly on the surface of carbon cloth fibers. Batch adsorption experiments of Eu(III) indicated that the nano-Mg(OH)2@CC composite maintained the excellent adsorption performance of nano-Mg(OH)2 toward Eu(III). After adsorption, the Eu containing composite was calcined under nitrogen atmosphere. The content of Eu2O3 in the calcined material was as high as 99.66%. Fixed-bed column experiments indicated that no blockage for Mg(OH)2@CC composite was observed during the treatment, while the complete blockage of occurred to nano-Mg(OH)2 at an effluent volume of 240 mL. Moreover, the removal efficiency of Mg(OH)2@CC was still higher than 90% until 4200 mL of effluent volume. This work provides a promising method for feasible application of nanoadsorbents in fixed-bed process to recycle low-concentration REEs from wastewater.

Carbon Cloth Supported Nano-Mg(OH)2 for the Enrichment and Recovery of Rare Earth Element Eu(III) From Aqueous Solution

PubMed Central

Li, Yinong; Tian, Chen; Liu, Weizhen; Xu, Si; Xu, Yunyun; Cui, Rongxin; Lin, Zhang

2018-01-01

Nano-Mg(OH)2 is attracting great attention as adsorbent for pre-concentration and recovery of rare earth elements (REEs) from low-concentration solution, due to its superior removal efficiency for REEs and environmental friendliness. However, the nanoparticles also cause some severe problems during application, including aggregation, blockage in fixed-bed column, as well as the difficulties in separation and reuse. Herein, in order to avoid the mentioned problems, a carbon cloth (CC) supported nano-Mg(OH)2 (nano-Mg(OH)2@CC) was synthesized by electrodeposition. The X-ray diffraction and scanning electron microscopy analysis demonstrated that the interlaced nano-sheet of Mg(OH)2 grew firmly and uniformly on the surface of carbon cloth fibers. Batch adsorption experiments of Eu(III) indicated that the nano-Mg(OH)2@CC composite maintained the excellent adsorption performance of nano-Mg(OH)2 toward Eu(III). After adsorption, the Eu containing composite was calcined under nitrogen atmosphere. The content of Eu2O3 in the calcined material was as high as 99.66%. Fixed-bed column experiments indicated that no blockage for Mg(OH)2@CC composite was observed during the treatment, while the complete blockage of occurred to nano-Mg(OH)2 at an effluent volume of 240 mL. Moreover, the removal efficiency of Mg(OH)2@CC was still higher than 90% until 4,200 mL of effluent volume. This work provides a promising method for feasible application of nanoadsorbents in fixed-bed process to recycle low-concentration REEs from wastewater. PMID:29721492

Simultaneous capture of metal, sulfur and chlorine by sorbents during fluidized bed incineration.

PubMed

Ho, T C; Chuang, T C; Chelluri, S; Lee, Y; Hopper, J R

2001-01-01

Metal capture experiments were carried out in an atmospheric fluidized bed incinerator to investigate the effect of sulfur and chlorine on metal capture efficiency and the potential for simultaneous capture of metal, sulfur and chlorine by sorbents. In addition to experimental investigation, the effect of sulfur and chlorine on the metal capture process was also theoretically investigated through performing equilibrium calculations based on the minimization of system free energy. The observed results have indicated that, in general, the existence of sulfur and chlorine enhances the efficiency of metal capture especially at low to medium combustion temperatures. The capture mechanisms appear to include particulate scrubbing and chemisorption depending on the type of sorbents. Among the three sorbents tested, calcined limestone is capable of capturing all the three air pollutants simultaneously. The results also indicate that a mixture of the three sorbents, in general, captures more metals than a single sorbent during the process. In addition, the existence of sulfur and chlorine apparently enhances the metal capture process.

An investigation of the mechanisms of calcination and sulfation in coal-water mixtures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Christofides, N.

1990-09-21

The purpose of this investigation is to study the mechanisms of sulfur capture when burning coal-water-limestone mixtures (CWLM) in fluidized beds. Special care is taken to make comparisons with to dry coal and sorbent under comparable experimental conditions. A series of experiments were performed in an eight-inch diameter bubbling fluidized bed combustor to address this problem. 33 refs., 17 figs., 5 tabs.

Low temperature pyrolysis of coal or oil shale in the presence of calcium compounds

DOEpatents

Khan, M. Rashid

1988-01-01

A coal pyrolysis technique or process is described in which particulate coal is pyrolyzed in the presence of about 5 to 21 wt. % of a calcium compound selected from calcium oxide, calcined (hydrate) dolomite, or calcined calcium hydrate to produce a high quality hydrocarbon liquid and a combustible product gas which are characterized by low sulfur content. The pyrolysis is achieved by heating the coal-calcium compound mixture at a relatively slow rate at a temperature of about 450.degree. to 700.degree. C. over a duration of about 10 to 60 minutes in a fixed or moving bed reactor. The gas exhibits an increased yield in hydrogen and C.sub.1 -C.sub.8 hydrocarbons and a reduction in H.sub.2 S over gas obtainable by pyrolyzing cola without the calcium compound. The liquid product obtained is of a sufficient quality to permit its use directly as a fuel and has a reduced sulfur and oxygen content which inhibits polymerization during storage.

Attrition of limestone by impact loading in fluidized beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fabrizio Scala; Fabio Montagnaro; Piero Salatino

2007-09-15

The present study addresses limestone attrition and fragmentation associated with impact loading, a process which may occur extensively in various regions of fluidized bed (FB) combustors/gasifiers, primarily the jetting region of the bottom bed, the exit region of the riser, and the cyclone. An experimental protocol for the characterization of the propensity of limestone to undergo attrition/fragmentation by impact loading is reported. The application of the protocol is demonstrated with reference to an Italian limestone whose primary fragmentation and attrition by surface wear have already been characterized in previous studies. The experimental procedure is based on the characterization of themore » amount and particle size distribution of the debris generated upon the impact of samples of sorbent particles against a target. Experiments were carried out at a range of particle impact velocities between 10 and 45 m/s, consistent with jet velocities corresponding to typical pressure drops across FB gas distributors. The protocol has been applied to either raw or preprocessed limestone samples. In particular, the effect of calcination, sulfation, and calcination/recarbonation cycles on the impact damage suffered by sorbent particles has been assessed. The measurement of particle voidage and pore size distribution by mercury intrusion was also accomplished to correlate fragmentation with the structural properties of the sorbent samples. Fragmentation by impact loading of the limestone is significant. Lime displays the largest propensity to undergo impact damage, followed by the sorbent sulfated to exhaustion, the recarbonated sorbent, and the raw limestone. Fragmentation of the raw limestone and of the sulfated lime follows a pattern typical of the failure of brittle materials. The fragmentation behavior of lime and recarbonated lime better conforms to a disintegration failure mode, with an extensive generation of very fine fragments. 27 refs., 9 figs. 1 tab.« less

A laboratory scale study on arsenic(V) removal from aqueous medium using calcined bauxite ore.

PubMed

Mohapatra, Debasish; Mishra, Debaraj; Park, Kyung Ho

2008-01-01

The present work deals with the As(V) removal from an aqueous medium by calcined refractory grade bauxite (CRB) as a function of solution pH, time, As(V) concentration and temperature. The residual As(V) was lowered from 2 mg/L to below 0.01 mg/L in the optimum pH range 4.0-7.0 using a 5 g/L CRB within 3 h contact time. The adsorption data fits well with Langmuir isotherm and yielded Langmuir monolayer capacity of 1.78 mg As(V)/g of CRB at pH 7.0. Presence of anions such as silicate and phosphate decreased As(V) adsorption efficiency. An increase temperature resulted a decrease in the amount of As(V) adsorbed by 6%. The continuous fixed bed column study showed that at the adsorbent bed depth of 30 cm and residence time of 168 min, the CRB was capable of treating 340 bed volumes of As(V) spiked water (C0 = 2 mg/L) before breakthrough (Ce = 0.01 mg/L). This solid adsorbent, although not reusable, can be considered for design of adsorption columns as an efficiency arsenic adsorption media.

Hydrogen sulfide capture by limestone and dolomite at elevated pressure. 1: Sorbent performance

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yrjas, K.P.; Zevenhoven, C.A.P.; Hupa, M.M.

1996-01-01

Sulfur emission control in fossil fuel gasification plants implies the removal of H{sub 2}S from the product gas either inside the furnace or in the gas clean-up system. In a fluidized-bed gasifier, in-bed sulfur capture can be accomplished by adding a calcium-based sorbent such as limestone or dolomite to the bend and removing the sulfur from the system with the bottom ash in the form of CaS. This work describes the H{sub 2}S uptake by a set of physically and chemically different limestones and dolomites under pressurized conditions, typically for those in a pressurized fluidized-bed gasifier (2 MPa, 950 C).more » The tests were done with a pressurized thermobalance at two p{sub CO{sub 2}} levels. Thus, the sulfidation of both calcined and uncalcined sorbents could be analyzed. The effect of p{sub H{sub 2}S} was also investigated for uncalcined limestones and half-calcined dolomites. The results are presented as conversion of CaCO{sub 3} or CaO to CaS vs time plots. The results are also compared with the sulfur capture performance of the same sorbents under pressurized combustion conditions.« less

Comparison of the biological H2S removal characteristics among four inorganic packing materials.

PubMed

Hirai, M; Kamamoto, M; Yani, M; Shoda, M

2001-01-01

Four inorganic packing materials were evaluated in terms of their availability as packing materials of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological H2S removal characteristics and some physical properties. Among porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calcinated soil (D), the superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of H2S per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately equal to C > D approximately equal to B, which is correlated with the maximum water content, porosity, and mean pore diameter.

Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

PubMed

Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

2015-01-23

Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts. Copyright © 2014 Elsevier B.V. All rights reserved.

Performance of a novel synthetic Ca-based solid sorbent suitable for desulfurizing flue gases in a fluidized bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pacciani, R.; Muller, C.R.; Davidson, J.F.

2009-08-05

The extent and mechanism of sulfation and carbonation of limestone, dolomite, and chalk, were compared with a novel, synthetic sorbent (85 wt % CaO and 15 wt % Ca{sub 12}A{sub l14}O{sub 33}), by means of experiments undertaken in a small, electrically heated fluidized bed. The sorbent particles were used either (I) untreated, sieved to two particle sizes and reacted with two different concentrations of SO{sub 2}, or (ii) after being cycled 20 times between carbonation, in 15 vol % CO{sub 2} in N2, and calcination, in pure N2, at 750 degrees C. The uptake of untreated limestone and dolomite wasmore » generally low (<0.2 g(SO{sub 2})/g(sorbent)), confirming previous results, However, the untreated chalk and the synthetic sorbent were found to be substantially more reactive with SO{sub 2}, and their final uptake was significantly higher (>0.5 g(SO{sub 2})/g(sorbent)) and essentially independent of the particle size. Here, comparisons are made on the basis of the sorbents in the calcined state. The capacities for the uptake of SO{sub 2}, on a basis of unit mass of calcined sorbent, were comparable for the chalk and the synthetic sorbent. However, previous work has demonstrated the ability of the synthetic sorbent to retain its capacity for CO{sub 2} over many cycles of carbonation and calcination: much more so than natural sorbents such as chalk and limestone. Accordingly, the advantage of the synthetic sorbent is that it could be used to remove CO{sub 2} from flue gases and, at the end of its life, to remove SO{sub 2} on a once-through basis.« less

Oil shale retorting and combustion system

DOEpatents

Pitrolo, Augustine A.; Mei, Joseph S.; Shang, Jerry Y.

1983-01-01

The present invention is directed to the extraction of energy values from l shale containing considerable concentrations of calcium carbonate in an efficient manner. The volatiles are separated from the oil shale in a retorting zone of a fluidized bed where the temperature and the concentration of oxygen are maintained at sufficiently low levels so that the volatiles are extracted from the oil shale with minimal combustion of the volatiles and with minimal calcination of the calcium carbonate. These gaseous volatiles and the calcium carbonate flow from the retorting zone into a freeboard combustion zone where the volatiles are burned in the presence of excess air. In this zone the calcination of the calcium carbonate occurs but at the expense of less BTU's than would be required by the calcination reaction in the event both the retorting and combustion steps took place simultaneously. The heat values in the products of combustion are satisfactorily recovered in a suitable heat exchange system.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bakel, Allen J.; Conner, Cliff; Quigley, Kevin

One of the missions of the Reduced Enrichment for Research and Test Reactors (RERTR) program (and now the National Nuclear Security Administrations Material Management and Minimization program) is to facilitate the use of low enriched uranium (LEU) targets for 99Mo production. The conversion from highly enriched uranium (HEU) to LEU targets will require five to six times more uranium to produce an equivalent amount of 99Mo. The work discussed here addresses the technical challenges encountered in the treatment of uranyl nitrate hexahydrate (UNH)/nitric acid solutions remaining after the dissolution of LEU targets. Specifically, the focus of this work is themore » calcination of the uranium waste from 99Mo production using LEU foil targets and the Modified Cintichem Process. Work with our calciner system showed that high furnace temperature, a large vent tube, and a mechanical shield are beneficial for calciner operation. One- and two-step direct calcination processes were evaluated. The high-temperature one-step process led to contamination of the calciner system. The two-step direct calcination process operated stably and resulted in a relatively large amount of material in the calciner cup. Chemically assisted calcination using peroxide was rejected for further work due to the difficulty in handling the products. Chemically assisted calcination using formic acid was rejected due to unstable operation. Chemically assisted calcination using oxalic acid was recommended, although a better understanding of its chemistry is needed. Overall, this work showed that the two-step direct calcination and the in-cup oxalic acid processes are the best approaches for the treatment of the UNH/nitric acid waste solutions remaining from dissolution of LEU targets for 99Mo production.« less

Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Sulfur control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, M.J.; Abbasian, J.; Akin, C.

1992-05-01

This topical report on Sulfur Control'' presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). The objective of the task on In-Bed Sulfur Capture was to determine the effectiveness of different sorbents (that is, limestone, calcined limestone, dolomite, and siderite)more » for capturing sulfur (as H{sub 2}S) in the reactor during hydroretorting. The objective of the task on Electrostatic Desulfurization was to determine the operating conditions necessary to achieve a high degree of sulfur removal and kerogen recovery in IIT's electrostatic separator. The objectives of the task on Microbial Desulfurization and Denitrification were to (1) isolate microbial cultures and evaluate their ability to desulfurize and denitrify shale, (2) conduct laboratory-scale batch and continuous tests to improve and enhance microbial removal of these components, and (3) determine the effects of processing parameters, such as shale slurry concentration, solids settling characteristics, agitation rate, and pH on the process.« less

Evaluation of Vitrification Processing Step for Rocky Flats Incinerator Ash

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wigent, W.L.; Luey, J.K.; Scheele, R.D.

In 1997, Pacific Northwest National Laboratory (PNNL) staff developed a processing option for incinerator ash at the Rocky Flats Environmental Technology Sites (RFETS). This work was performed with support from Los Alamos National Laboratory (LANL) and Safe Sites of Colorado (SSOC). A description of the remediation needs for the RFETS incinerator ash is provided in a report summarizing the recommended processing option for treatment of the ash (Lucy et al. 1998). The recommended process flowsheet involves a calcination pretreatment step to remove carbonaceous material followed by a vitrification processing step for a mixture of glass tit and calcined incinerator ash.more » Using the calcination pretreatment step to remove carbonaceous material reduced process upsets for the vitrification step, allowed for increased waste loading in the final product, and improved the quality of the final product. Figure 1.1 illustrates the flow sheet for the recommended processing option for treatment of RFETS incinerator ash. In 1998, work at PNNL further developed the recommended flow sheet through a series of studies to better define the vitrification operating parameters and to address secondary processing issues (such as characterizing the offgas species from the calcination process). Because a prototypical rotary calciner was not available for use, studies to evaluate the offgas from the calcination process were performed using a benchtop rotary calciner and laboratory-scale equipment (Lucy et al. 1998). This report focuses on the vitrification process step after ash has been calcined. Testing with full-scale containers was performed using ash surrogates and a muffle furnace similar to that planned for use at RFETS. Small-scale testing was performed using plutonium-bearing incinerator ash to verify performance of the waste form. Ash was not obtained from RFETS because of transportation requirements to calcine the incinerator ash prior to shipment of the material. Because part of PNNL's work was to characterize the ash prior to calcination and to investigate the effect of calcination on product quality, representative material was obtained from LANL. Ash obtained from LANL was selected based on its similarity to that currently stored at RFETS. The plutonium-bearing ashes obtained from LANL are likely from a RFETS incinerator, but the exact origin was not identified.« less

Catalyst and process development for synthesis gas conversion to isobutylene. Final report, September 1, 1990--January 31, 1994

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anthony, R.G.; Akgerman, A.

1994-05-06

Previous work on isosynthesis (conversion of synthesis gas to isobutane and isobutylene) was performed at very low conversions or extreme process conditions. The objectives of this research were (1) determine the optimum process conditions for isosynthesis; (2) determine the optimum catalyst preparation method and catalyst composition/properties for isosynthesis; (3) determine the kinetics for the best catalyst; (4) develop reactor models for trickle bed, slurry, and fixed bed reactors; and (5) simulate the performance of fixed bed trickle flow reactors, slurry flow reactors, and fixed bed gas phase reactors for isosynthesis. More improvement in catalyst activity and selectivity is needed beforemore » isosynthesis can become a commercially feasible (stand-alone) process. Catalysts prepared by the precipitation method show the most promise for future development as compared with those prepared hydrothermally, by calcining zirconyl nitrate, or by a modified sol-gel method. For current catalysts the high temperatures (>673 K) required for activity also cause the production of methane (because of thermodynamics). A catalyst with higher activity at lower temperatures would magnify the unique selectivity of zirconia for isobutylene. Perhaps with a more active catalyst and acidification, oxygenate production could be limited at lower temperatures. Pressures above 50 atm cause an undesirable shift in product distribution toward heavier hydrocarbons. A model was developed that can predict carbon monoxide conversion an product distribution. The rate equation for carbon monoxide conversion contains only a rate constant and an adsorption equilibrium constant. The product distribution was predicted using a simple ratio of the rate of CO conversion. This report is divided into Introduction, Experimental, and Results and Discussion sections.« less

Pressurized fluidized-bed hydroretorting of Eastern oil shales -- Sulfur control. Topical report for Subtask 3.1, In-bed sulfur capture tests; Subtask 3.2, Electrostatic desulfurization; Subtask 3.3, Microbial desulfurization and denitrification

DOE Office of Scientific and Technical Information (OSTI.GOV)

Roberts, M.J.; Abbasian, J.; Akin, C.

1992-05-01

This topical report on ``Sulfur Control`` presents the results of work conducted by the Institute of Gas Technology (IGT), the Illinois Institute of Technology (IIT), and the Ohio State University (OSU) to develop three novel approaches for desulfurization that have shown good potential with coal and could be cost-effective for oil shales. These are (1) In-Bed Sulfur Capture using different sorbents (IGT), (2) Electrostatic Desulfurization (IIT), and (3) Microbial Desulfurization and Denitrification (OSU and IGT). The objective of the task on In-Bed Sulfur Capture was to determine the effectiveness of different sorbents (that is, limestone, calcined limestone, dolomite, and siderite)more » for capturing sulfur (as H{sub 2}S) in the reactor during hydroretorting. The objective of the task on Electrostatic Desulfurization was to determine the operating conditions necessary to achieve a high degree of sulfur removal and kerogen recovery in IIT`s electrostatic separator. The objectives of the task on Microbial Desulfurization and Denitrification were to (1) isolate microbial cultures and evaluate their ability to desulfurize and denitrify shale, (2) conduct laboratory-scale batch and continuous tests to improve and enhance microbial removal of these components, and (3) determine the effects of processing parameters, such as shale slurry concentration, solids settling characteristics, agitation rate, and pH on the process.« less

Alcoa Pressure Calcination Process for Alumina

NASA Astrophysics Data System (ADS)

Sucech, S. W.; Misra, C.

A new alumina calcination process developed at Alcoa Laboratories is described. Alumina is calcined in two stages. In the first stage, alumina hydrate is heated indirectly to 500°C in a decomposer vessel. Released water is recovered as process steam at 110 psig pressure. Partial transformation of gibbsite to boehmite occurs under hydrothermal conditions of the decomposer. The product from the decomposer containing about 5% LOI is then calcined by direct heating to 850°C to obtain smelting grade alumina. The final product is highly attrition resistant, has a surface area of 50-80 m2/g and a LOI of less than 1%. Accounting for the recovered steam, the effective fuel consumption for the new calcination process is only 1.6 GJ/t A12O3.

Summary of Calcine Disposal Development Using Hot Isostatic Pressing

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bateman, Ken; Wahlquist, Dennis; Hart, Edward

2015-03-01

Battelle Energy Alliance, LLC, has demonstrated the effectiveness of the hot isostatic press (HIP) process for treatment of hazardous high-level waste known as calcine that is stored at the Idaho Nuclear Technology and Engineering Center (INTEC) at Idaho National Laboratory. HIP trials performed with simulated calcines at Idaho National Laboratory’s Materials and Fuels Complex and an Australian Nuclear Science and Technology Organization facility from 2007 to 2010 produced a dense, monolithic waste form with increased chemical durability and effective (storage) volume reductions of ~10 to ~70% compared to granular calcine forms. In December 2009, the U.S. Department of Energy signedmore » an amended Record of Decision selecting HIP technology as the treatment method for the 4,400 m3 of granular zirconia and alumina calcine stored at INTEC. Testing showed that HIP treatment reduces the risks associated with radioactive and hazardous constituent release, post-production handling, and long-term (repository) storage of calcines and would result in estimated storage cost savings in the billions of dollars. Battelle Energy Alliance has the ability to complete pilot-scale HIP processing of INTEC calcine, which is the next necessary step in implementing HIP processing as a calcine treatment method.« less

Carbon dioxide capture from a cement manufacturing process

DOEpatents

Blount, Gerald C [North Augusta, SC; Falta, Ronald W [Seneca, SC; Siddall, Alvin A [Aiken, SC

2011-07-12

A process of manufacturing cement clinker is provided in which a clean supply of CO.sub.2 gas may be captured. The process also involves using an open loop conversion of CaO/MgO from a calciner to capture CO.sub.2 from combustion flue gases thereby forming CaCO.sub.3/CaMg(CO.sub.3).sub.2. The CaCO.sub.3/CaMg(CO.sub.3).sub.2 is then returned to the calciner where CO.sub.2 gas is evolved. The evolved CO.sub.2 gas, along with other evolved CO.sub.2 gases from the calciner are removed from the calciner. The reactants (CaO/MgO) are feed to a high temperature calciner for control of the clinker production composition.

Study of variation grain size in desulfurization process of calcined petroleum coke

NASA Astrophysics Data System (ADS)

Pintowantoro, Sungging; Setiawan, Muhammad Arif; Abdul, Fakhreza

2018-04-01

Indonesia is a country with abundant natural resources, such as mineral mining and petroleum. In petroleum processing, crude oil can be processed into a source of fuel energy such as gasoline, diesel, oil, petroleum coke, and others. One of crude oil potentials in Indonesia is petroleum coke. Petroleum coke is a product from oil refining process. Sulfur reducing process in calcined petroleum cokes can be done by desulfurization process. The industries which have potential to become petroleum coke processing consumers are industries of aluminum smelting (anode, graphite block, carbon mortar), iron riser, calcined coke, foundry coke, etc. Sulfur reducing process in calcined petroleum coke can be done by thermal desulfurization process with alkaline substance NaOH. Desulfurization of petroleum coke process can be done in two ways, which are thermal desulfurization and hydrodesulphurization. This study aims to determine the effect of various grain size on sulfur, carbon, and chemical bond which contained by calcined petroleum coke. The raw material use calcined petroleum coke with 0.653% sulfur content. The grain size that used in this research is 50 mesh, then varied to 20 mesh and 100 mesh for each desulfurization process. Desulfurization are tested by ICP, UV-VIS, and FTIR to determine levels of sulfur, carbon, chemical bonding and sulfur dissolved water which contained in the residual washing of calcined petroleum coke. From various grain size that mentioned before, the optimal value is on 100 mesh grain size, where the sulfur content in petroleum coke is 0.24% and carbon content reaches the highest level of 97.8%. Meanwhile for grain size 100 mesh in the desulfurization process is enough to break the chemical bonds of organic sulfur in petroleum coke.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bundy, R.D.; Alderfer, R.B.

Bench-scale tests of the direct calcination process for Portsmouth were conducted using batch pot calcination of simulated and actual raffinate wastes. These studies included investigation of the evaporation step needed to concentrate the raffinate before calcination. Tests were conducted at calcination temperatures of 600, 700, 1000, and 1200/sup 0/F with two levels of evaporative concentration before calcination at 1000/sup 0/F. Evaporation only tests were also made. Performance of the bench-scale system was excellent. A calcination temperature of 715/sup 0/F indicated that 80 to 100% of the Tc was retained in the calcined solids, while all of the nitrates were decomposedmore » to oxides. With calcination temperatures of greater than or equal to 1000/sup 0/F, part of the Tc escaped from the calcination pot to the scrubber. Below 700/sup 0/F, not all of the nitrates were decomposed to oxides. Most of the U remained in the calcined solids for calcination temperatures of less than or equal to 1000/sup 0/F. The mass of solids remaining after calcination was 4 to 5% of the original raffinate for calcination temperatures from 700 to 1000/sup 0/F. Flow rate through the off-gas treatment system was variable. The water scrubber had a good removal efficiency for nitrate and most metals, but not for uranium. The trapping efficiency of the limestone trap for nitrate was low. Flowsheet studies indicate that enough U would pass through the scrubber and chemical traps to cause an unacceptably high release of radioactivity if the assay of the uranium exceeded 33%. A small HEPA filter after the limestone chemical traps is recommended to reduce U emissions. A flowsheet was developed for a full-scale process for the direct calcination of raffinate waste.« less

10. VIEW OF CALCINER IN ROOM 146148. THE CALCINER HEATED ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

10. VIEW OF CALCINER IN ROOM 146-148. THE CALCINER HEATED PLUTONIUM PEROXIDE TO CONVERT IT TO PLUTONIUM OXIDE. THE PROCESS REMOVED RESIDUAL WATER AND NITRIC ACID LEAVING A DRY, POWDERED PRODUCT. (4/29/65) - Rocky Flats Plant, Plutonium Recovery & Fabrication Facility, North-central section of plant, Golden, Jefferson County, CO

Retrieval System for Calcined Waste for the Idaho Cleanup Project - 12104

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eastman, Randy L.; Johnston, Beau A.; Lower, Danielle E.

This paper describes the conceptual approach to retrieve radioactive calcine waste, hereafter called calcine, from stainless steel storage bins contained within concrete vaults. The retrieval system will allow evacuation of the granular solids (calcine) from the storage bins through the use of stationary vacuum nozzles. The nozzles will use air jets for calcine fluidization and will be able to rotate and direct the fluidization or displacement of the calcine within the bin. Each bin will have a single retrieval system installed prior to operation to prevent worker exposure to the high radiation fields. The addition of an articulated camera armmore » will allow for operations monitoring and will be equipped with contingency tools to aid in calcine removal. Possible challenges (calcine bridging and rat-holing) associated with calcine retrieval and transport, including potential solutions for bin pressurization, calcine fluidization and waste confinement, are also addressed. The Calcine Disposition Project has the responsibility to retrieve, treat, and package HLW calcine. The calcine retrieval system has been designed to incorporate the functions and technical characteristics as established by the retrieval system functional analysis. By adequately implementing the highest ranking technical characteristics into the design of the retrieval system, the system will be able to satisfy the functional requirements. The retrieval system conceptual design provides the means for removing bulk calcine from the bins of the CSSF vaults. Top-down vacuum retrieval coupled with an articulating camera arm will allow for a robust, contained process capable of evacuating bulk calcine from bins and transporting it to the processing facility. The system is designed to fluidize, vacuum, transport and direct the calcine from its current location to the CSSF roof-top transport lines. An articulating camera arm, deployed through an adjacent access riser, will work in conjunction with the retrieval nozzle to aid in calcine fluidization, remote viewing, clumped calcine breaking and recovery from off-normal conditions. As the design of the retrieval system progresses from conceptual to preliminary, increasing attention will be directed toward detailed design and proof-of- concept testing. (authors)« less

Thermal decomposition of dolomite under CO2: insights from TGA and in situ XRD analysis.

PubMed

Valverde, Jose Manuel; Perejon, Antonio; Medina, Santiago; Perez-Maqueda, Luis A

2015-11-28

Thermal decomposition of dolomite in the presence of CO2 in a calcination environment is investigated by means of in situ X-ray diffraction (XRD) and thermogravimetric analysis (TGA). The in situ XRD results suggest that dolomite decomposes directly at a temperature around 700 °C into MgO and CaO. Immediate carbonation of nascent CaO crystals leads to the formation of calcite as an intermediate product of decomposition. Subsequently, decarbonation of this poorly crystalline calcite occurs when the reaction is thermodynamically favorable and sufficiently fast at a temperature depending on the CO2 partial pressure in the calcination atmosphere. Decarbonation of this dolomitic calcite occurs at a lower temperature than limestone decarbonation due to the relatively low crystallinity of the former. Full decomposition of dolomite leads also to a relatively low crystalline CaO, which exhibits a high reactivity as compared to limestone derived CaO. Under CO2 capture conditions in the Calcium-Looping (CaL) process, MgO grains remain inert yet favor the carbonation reactivity of dolomitic CaO especially in the solid-state diffusion controlled phase. The fundamental mechanism that drives the crystallographic transformation of dolomite in the presence of CO2 is thus responsible for its fast calcination kinetics and the high carbonation reactivity of dolomitic CaO, which makes natural dolomite a potentially advantageous alternative to limestone for CO2 capture in the CaL technology as well as SO2in situ removal in oxy-combustion fluidized bed reactors.

Mercury in soil near a long-term air emission source in southeastern Idaho

USGS Publications Warehouse

Abbott, M.L.; Susong, D.D.; Olson, M.; Krabbenhoft, D.P.

2003-01-01

At the Idaho National Engineering and Environmental Laboratory in southeastern Idaho, a 500??C fluidized bed calciner was intermittently operated for 37 years, with measured Hg emission rates of 9-11 g/h. Surface soil was sampled at 57 locations around the facility to determine the spatial distribution of Hg fallout and surface Hg variability, and to predict the total residual Hg mass in the soil from historical emissions. Measured soil concentrations were slightly higher (p<0.05) within 5 km of the source but were overall very low (15-20 ng/g) compared to background Hg levels published for similar soils in the USA (50-70 ng/g). Concentrations decreased 4%/cm with depth and were found to be twice as high under shrubs and in depressions. Mass balance calculations accounted for only 2.5-20% of the estimated total Hg emitted over the 37-year calciner operating history. These results suggest that much of the Hg deposited from calciner operations may have been reduced in the soil and re-emitted as Hg(0) to the global atmospheric pool.

The influence of calcination temperatures on the acid-based properties and catalytic activity for the 1,3-butadiene synthesis from ethanol/acetaldehyde mixture

NASA Astrophysics Data System (ADS)

Gao, Meixiang; Jiang, Haoxi; Zhang, Minhua

2018-05-01

The influences of the calcination temperature on the catalysts' acid-based properties and catalytic activity for the 1,3-butadiene synthesis from ethanol are investigated. The results show that the 2 wt% ZrO2/Nano-SiO2 calcined at 773 K shows the best performance with the selectivity of 93.18% and conversion of 58.52% when reacted at 593 K, a WHSV of 1.8 h-1 and 3.5:1 volume ratio ethanol-to-acetaldehyde in an atmospheric fixed-bed reactor. Prepared catalysts were characterized by N2 adsorption-desorption, XRD, temperature-programmed desorption of NH3 and CO2, FTIR spectroscopy of adsorbed pyridine and CO2. Based on the relationship between the catalyst activity and its properties, the fact can be presumed that the formation and strength of Zrsbnd Osbnd Si bond determines the acid-based properties of the catalyst. In addition, moderate-intensity weak acid-basic sites are more suitable for ethanol conversion to BD with the amount of acid and basic sites as close as possible.

ZnO-based regenerable sulfur sorbents for fluid-bed/transport reactor applications

DOEpatents

Slimane, Rachid B.; Abbasian, Javad; Williams, Brett E.

2004-09-21

A method for producing regenerable sulfur sorbents in which a support material precursor is mixed with isopropanol and a first portion of deionized water at an elevated temperature to form a sol mixture. A metal oxide precursor comprising a metal suitable for use as a sulfur sorbent is dissolved in a second portion of deionized water, forming a metal salt solution. The metal salt solution and the sol mixture are mixed with a sol peptizing agent while heating and stirring, resulting in formation of a peptized sol mixture. The metal oxide precursor is dispersed substantially throughout the peptized sol mixture, which is then dried, forming a dry peptized sol mixture. The dry peptized sol mixture is then calcined and the resulting calcined material is then converted to particles.

Investigation of the processing conditions for the synthesis of rod-shaped LiCoO2

NASA Astrophysics Data System (ADS)

Kim, Taejoong; Kim, Yongseon

2018-07-01

We investigate the processing conditions for the synthesis of rod-shaped LiCoO2 (LCO) by a solid-state calcination of a precursor material which was prepared by a hydrothermal method. The rod-like morphology appeared to be easily broken due to the growth of primary crystals recrystallized during the calcination process. Therefore, it is crucial to maintain the temperature under a certain limit. However, the temperature must be high enough to obtain proper crystallinity of the LCO, ideally above 800 °C. Thus, we determined the optimal calcination temperature condition from the common range of temperatures that satisfies both these limiting conditions. The precursor with average diameter of 1 µm sustained the rod shape at calcination temperatures of up to 900 °C; therefore, the optimum calcination temperature could be determined between 800 and 900 °C. Whereas, a proper calcination temperature could not be found for the precursor with 500 nm of diameter because the rod shape did not maintain even at 700 °C. Thus, the maximum temperature at which the rod shape is retained decreases with smaller diameter of the precursor rods, indicating adjusting the diameter above a limiting value is necessary to prepare LCO rod by conventional solid state calcination.

Calcinations effect on the grain size distributions Al2O3 powder

NASA Astrophysics Data System (ADS)

Issa, Tarik Talib; Mohammed, Awattif A.; Kamil, Dunia

2012-09-01

Fine of Al2O3 Powder was calcined at 200°C, 400°C, 600°C, and 800°C respectively for 2 hours under static air, x-ray diffraction, optical microscope and grain size distribution were done to analysis the resulting data after calcinations process. Batter particle size was achieved at 800°C of value (0.486) μm, while batter particles mean value of size 7.18 μm was found at 400°C. SEM micrographs shows that the agglomerate particles were vanished due to the calcinations process.

Calcination does not remove all carbon from colloidal nanocrystal assemblies

DOE PAGES

Mohapatra, Pratyasha; Shaw, Santosh; Mendivelso-Perez, Deyny; ...

2017-12-11

Removing organics from hybrid nanostructures is a crucial step in many bottom-up materials fabrication approaches. It is usually assumed that calcination is an effective solution to this problem, especially for thin films. This assumption has led to its application in thousands of papers. Here in this paper, we show that this general assumption is incorrect by using a relevant and highly controlled model system consisting of thin films of ligand-capped ZrO 2 nanocrystals. After calcination at 800 °C for 12 h, while Raman spectroscopy fails to detect the ligands after calcination, elastic backscattering spectrometry characterization demonstrates that ~18% of themore » original carbon atoms are still present in the film. By comparison plasma processing successfully removes the ligands. Our growth kinetic analysis shows that the calcined materials have significantly different interfacial properties than the plasma-processed counterparts. Calcination is not a reliable strategy for the production of single-phase all-inorganic materials from colloidal nanoparticles.« less

Fluoride removal from water using a magnesia-pullulan composite in a continuous fixed-bed column.

PubMed

Ye, Yuanyao; Yang, Jing; Jiang, Wei; Kang, Jianxiong; Hu, Ying; Ngo, Huu Hao; Guo, Wenshan; Liu, Yiwen

2018-01-15

A magnesia-pullulan composite (MgOP) was previously shown to effectively remove fluoride from water. In the present study, a continuous fixed-bed column was used to examine the application of the composite at an industrial scale. The influencing parameters included bed mass (4.0, 6.0 and 8.0 g), influent flow rate (8, 16 and 32 mL/min), inlet fluoride concentration (5, 10 and 20 mg/L), reaction temperature (20, 30 and 40 °C), influent pH (4, 7 and 10) and other existing anions (HCO 3 - , SO 4 2- , Cl - and NO 3 - ), through which the breakthrough curves could be depicted for the experimental data analysis. The results indicated that MgOP is promising for fluoride removal with a defluoridation capacity of 16.6 mg/g at the bed mass of 6.0 g, influent flow rate of 16 mL/min and inlet fluoride concentration of 10 mg/L. The dynamics of the fluoride adsorption process were modeled using the Thomas and Yan models, in which the Yan model presented better predictions for the breakthrough curves than the Thomas model. Moreover, the concentration of magnesium in the effluent was monitored to determine Mg stability in the MgOP composite. Results indicated the effluent concentration of Mg 2+ ions could be kept at a safe level. Calcination of fluoride-loaded MgOP effectively regenerated the material. Copyright © 2017 Elsevier Ltd. All rights reserved.

Method of repressing the precipitation of calcium fluozirconate

DOEpatents

Newby, B.J.; Rhodes, D.W.

1973-12-25

Boric acid or a borate salt is added to aqueous solutions of fluoride containing radioactive wastes generated during the reprocessing of zirconium alloy nuclear fuels which are to be converted to solid form by calcining in a fluidized bed. The addition of calcium nitrate to the aqueous waste solutions to prevent fluoride volatility during calcination, causes the precipitation of calcium fluozirconate, which tends to form a gel at fluoride concentrations of 3.0 M or greater. The boron containing species introduced into the solution by the addition of the boric acid or borate salt retard the formation of the calcium fluozirconate precipitate and prevent formation of the gel. These boron containing species can be introduced into the solution by the addition of a borate salt but preferably are introduced by the addition of an aqueous solution of boric acid. (Official Gazette)

Comparison of the biological NH3 removal characteristics among four inorganic packing materials.

PubMed

Hirai, M; Kamamoto, M; Yani, M; Shoda, M

2001-01-01

Four inorganic packing materials were evaluated in terms of their availability as a packing material of a packed tower deodorization apparatus (biofilter) from the viewpoints of biological NH3 removal characteristics and some physical properties. Porous ceramics (A), calcinated cristobalite (B), calcinated and formed obsidian (C), granulated and calculated soil (D) were used. The superiority of these packing materials determined based on the values of non-biological removal per unit weight or unit volume of packing material, complete removal capacity of NH3 per unit weight of packing material per day or unit volume of packing material per day and pressure drop of the packed bed was in the order of A approximately = C > B > or = D. Packing materials A and C with high porosity, maximum water content, and suitable mean pore diameter showed excellent removal capacity.

Mercury mine drainage and processes that control its environmental impact

USGS Publications Warehouse

Rytuba, J.J.

2000-01-01

Mine drainage from mercury mines in the California Coast Range mercury mineral belt is an environmental concern because of its acidity and high sulfate, mercury, and methylmercury concentrations. Two types of mercury deposits are present in the mineral belt, silica-carbonate and hot-spring type. Mine drainage is associated with both deposit types but more commonly with the silica-carbonate type because of the extensive underground workings present at these mines. Mercury ores consisting primarily of cinnabar were processed in rotary furnaces and retorts and elemental mercury recovered from condensing systems. During the roasting process mercury phases more soluble than cinnabar are formed and concentrated in the mine tailings, commonly termed calcines. Differences in mineralogy and trace metal geochemistry between the two deposit types are reflected in mine drainage composition. Silica-carbonate type deposits have higher iron sulfide content than hot- spring type deposits and mine drainage from these deposits may have extreme acidity and very high concentrations of iron and sulfate. Mercury and methylmercury concentrations in mine drainage are relatively low at the point of discharge from mine workings. The concentration of both mercury species increases significantly in mine drainage that flows through and reacts with calcines. The soluble mercury phases in the calcines are dissolved and sulfate is added such that methylation of mercury by sulfate reducing bacteria is enhanced in calcines that are saturated with mine drainage. Where mercury mine drainage enters and first mixes with stream water, the addition of high concentrations of mercury and sulfate generates a favorable environment for methylation of mercury. Mixing of oxygenated stream water with mine drainage causes oxidation of dissolved iron(II) and precipitation of iron oxyhydroxide that accumulates in the streambed. Both mercury and methylmercury are strongly adsorbed onto iron oxyhydroxide over the pH range of 3.2-7.1 in streams impacted by mine drainage. The dissolved fraction of both mercury species is depleted and concentrated in iron oxyhydroxide such that the amount of iron oxyhydroxide in the water column reflects the concentration of mercury species. In streams impacted by mine drainage, mercury and methylmercury are transported and adsorbed onto particulate phases. During periods of low stream flow, fine-grained iron hydroxide sediment accumulates in the bed load of the stream and adsorbs mercury and methylmercury such that both forms of mercury become highly enriched in the iron oxyhydroxide sediment. During high-flow events, mercury- and methylmercury-enriched iron hydroxide sediment is transported into larger aquatic systems producing a high flux of bioavailable mercury. (C) 2000 Elsevier Science B.V.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohapatra, Pratyasha; Shaw, Santosh; Mendivelso-Perez, Deyny

Removing organics from hybrid nanostructures is a crucial step in many bottom-up materials fabrication approaches. It is usually assumed that calcination is an effective solution to this problem, especially for thin films. This assumption has led to its application in thousands of papers. Here in this paper, we show that this general assumption is incorrect by using a relevant and highly controlled model system consisting of thin films of ligand-capped ZrO 2 nanocrystals. After calcination at 800 °C for 12 h, while Raman spectroscopy fails to detect the ligands after calcination, elastic backscattering spectrometry characterization demonstrates that ~18% of themore » original carbon atoms are still present in the film. By comparison plasma processing successfully removes the ligands. Our growth kinetic analysis shows that the calcined materials have significantly different interfacial properties than the plasma-processed counterparts. Calcination is not a reliable strategy for the production of single-phase all-inorganic materials from colloidal nanoparticles.« less

Recovery of copper from PVC multiwire cable waste by steam gasification.

PubMed

Zabłocka-Malicka, Monika; Rutkowski, Piotr; Szczepaniak, Włodzimierz

2015-12-01

Screened multiwire, PVC insulated tinned copper cable was gasified with steam at high temperature (HTSG) under atmospheric pressure for recovery of cooper. Gases from the process were additionally equilibrated at 850°C on the bed of calcined clay granules and more than 98% of C+H content in the cable was transformed to non-condensing species. Granules prepared from local clay were generally resistant for chlorination, there was also almost no deposition of metals, Cu and Sn, on the catalytic bed. It was found that 28% of chlorine reacted to form CaCl2, 71% was retained in aqueous condensate and only 0.6% was absorbed in alkaline scrubber. More than 99% of calcium existed in the process solid residue as a mixture of calcium chloride and calcium oxide/hydroxide. PVC and other hydrocarbon constituents were completely removed from the cable sample. Copper was preserved in original form and volatilization of copper species appeared insignificant. Tin was alloying with copper and its volatilization was less than 1%. Fractionation and speciation of metals, chlorine and calcium were discussed on the basis of equilibrium model calculated with HSC Chemistry software. High temperature steam gasification prevents direct use of the air and steam/water is in the process simultaneously gaseous carrier and reagent, which may be recycled together with hydrocarbon condensates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Sodium Bearing Waste Processing Alternatives Analysis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Murphy, James Anthony; Palmer, Brent J; Perry, Keith Joseph

2003-12-01

A multidisciplinary team gathered to develop a BBWI recommendation to DOE-ID on the processing alternatives for the sodium bearing waste in the INTEC Tank Farm. Numerous alternatives were analyzed using a rigorous, systematic approach. The data gathered were evaluated through internal and external peer reviews for consistency and validity. Three alternatives were identified to be top performers: Risk-based Calcination, MACT to WIPP Calcination and Cesium Ion Exchange. A dual-path through early Conceptual design is recommended for MACT to WIPP Calcination and Cesium Ion Exchange since Risk-based Calcination does not require design. If calcination alternatives are not considered based on givingmore » Type of Processing criteria significantly greater weight, the CsIX/TRUEX alternative follows CsIX in ranking. However, since CsIX/TRUEX shares common uncertainties with CsIX, reasonable backups, which follow in ranking, are the TRUEX and UNEX alternatives. Key uncertainties must be evaluated by the decision-makers to choose one final alternative. Those key uncertainties and a path forward for the technology roadmapping of these alternatives is provided.« less

Trichloroethylene decomposition and in-situ dry sorption of Cl-products by calcium oxides prepared from hydrated limes.

PubMed

Gotoh, Yoshimi; Iwata, Goichi; Choh, Kyaw; Kubota, Mitsuhiro; Matsuda, Hitoki

2011-10-01

A comparison of CaOs produced by calcining two types of hydrated lime and calcium carbonate was made for decomposition of trichloroethylene and in-situ dry sorption of the decomposed Cl-products using a lab-scale gas flow type tubular packed bed reactor. About 20 mg of CaO sample was mixed with about 2 g of Al2O3 particles and packed in the reactor and allowed to react with a flowing standard gas containing 500 ppm of C2HCl3 (N2 balance) at 673 and 873 K, under the condition that the reaction of CaO with C2HCl3 might be completed within a few hours. It was found that no thermal decomposition of C2HCl3 at or below 673 K was observed in a reactor packed only with Al2O3 particles. However, a considerable amount of decomposition of C2HCl3 was obtained in a reactor packed with CaO and Al2O3, even at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 673 K, decomposition of 0.42 mol of C2HCl3 and in-situ absorption product of 0.53 mol of CaCl2 were obtained. At 873 K, about 46% of C2HCl3 was thermally decomposed. The total amount of C2HCl3 decomposed in CaO-Al2O3 particle bed at 873 K became nearly twice larger than that at 673 K. For 1 mol of CaO prepared by calcining highly reactive Ca(OH)2 at 873 K, decomposition of 0.59 mol of C2HCl3 and in-situ absorption product of 0.67 mol of CaCl2 were obtained. Small amounts of C2Cl2, C2Cl4, CCl4, etc. were detected during decomposition of C2HCl3 at 673 and 873 K. It was recognized that the data on decomposition of C2HCl3 as well as in-situ dry sorption of Cl-products in CaO particle bed were correlated with specific surface area of the CaO employed. Copyright © 2011 Elsevier Ltd. All rights reserved.

In-situ XAFS study for calcination process of Cr catalyst supported on γ-Al2O3 and SiO2

NASA Astrophysics Data System (ADS)

Watanabe, T.; Ikeda, K.; Katayama, M.; Inada, Y.

2016-05-01

The catalytic performance is largely affected by the oxidation state of supported Cr species, and its control changes the activity of Cr catalysts and the selectivity of products. In this study, the calcination process of the supported Cr catalysts on γ-Al2O3 and SiO2 was investigated by in-situ XAFS spectroscopy. The hydrate species was first supported by the impregnation method and was converted to CrO3 via Cr2O3 during the calcination process on both supporting materials. It was found that the temperature to complete the oxidation from Cr2O3 to CrO3 on SiO2 was higher than that on γ-Al2O3. The similarity of the interatomic distance between the surface oxygen atoms of the intermediate Cr2O3 species to that of SiO2 contributes to the stabilization of Cr2O3 on SiO2 during the calcination process.

Wet calcining of trona (sodium sesquicarbonate) and bicarbonate in a mixed solvent

NASA Astrophysics Data System (ADS)

Gärtner, R. S.; Witkamp, G. J.

2002-04-01

Trona ore is used in large amounts for the production of soda ash. A key step in this process is the conversion of trona (sodium sesquicarbonate: Na 2CO 3·NaHCO 3·2H 2O) into soda (sodium carbonate anhydrate: Na 2CO 3). Currently, this conversion is done industrially by calcining of the raw ore in rotary calciners at ca. 120°C or higher (Natural Soda Ash—Occurrences, Processing, and Use, Van Nostrand Reinhold, New York, 1991, p. 267). Trona can however be converted at lower temperatures by using a "wet calcining" technique. In this technique, trona is contacted with an organic or mixed organic-aqueous solvent at a conversion temperature that depends on the water activity of the used solvent. In pure ethylene glycol this temperature can be as low as 55°C. The conversion by "wet calcining" occurs very similar to that in the regular dry calcining process via a solid phase conversion. The anhydrate crystals form directly from the solid trona. This produces pseudomorphs (J. Chem. Eng. Data 8(3) (1963) 301), i.e. agglomerates of fine anhydrate crystals (1-10 μm). At high temperatures, dense, finely pored agglomerates are formed, while the outer shape of the agglomerate retains the prism shape of the trona crystal. At low conversion temperatures, loosely packed or even unstable agglomerates are found.

Manufacture of barium hexaferrite (BaO3.98Fe2O3) from iron oxide waste of grinding process by using calcination process

NASA Astrophysics Data System (ADS)

Idayanti, N.; Dedi; Kristiantoro, T.; Mulyadi, D.; Sudrajat, N.; Alam, G. F. N.

2018-03-01

The utilization of iron oxide waste of grinding process as raw materials for making barium hexaferrite has been completed by powder metallurgy method. The iron oxide waste was purified by roasting at 800 °C temperature for 3 hours. The method used varying calcination temperature at 1000, 1100, 1200, and 1250 °C for 3 hours. The starting iron oxide waste (Fe2O3) and barium carbonate (BaCO3) were prepared by mol ratio of Fe2O3:BaCO3 from the formula BaO3.98Fe2O3. Some additives such as calcium oxide (CaO), silicon dioxide (SiO2), and polyvinyl alcohol (PVA) were added after calcination process. The samples were formed at the pressure of 2 ton/cm2 and sintered at the temperature of 1250 °C for 1 hour. The formation of barium hexaferrite compounds after calcination is determined by X-Ray diffraction. The magnetic properties were observed by Permagraph-Magnet Physik with the optimum characteristic at calcination temperature of 1250 °C with the induction of remanence (Br) = 1.38 kG, coercivity (HcJ) = 4.533 kOe, product energy maximum (BHmax) = 1.086 MGOe, and density = 4.33 g/cm3.

Nuclear forensics investigation of morphological signatures in the thermal decomposition of uranyl peroxide.

PubMed

Schwerdt, Ian J; Olsen, Adam; Lusk, Robert; Heffernan, Sean; Klosterman, Michael; Collins, Bryce; Martinson, Sean; Kirkham, Trenton; McDonald, Luther W

2018-01-01

The analytical techniques typically utilized in a nuclear forensic investigation often provide limited information regarding the process history and production conditions of interdicted nuclear material. In this study, scanning electron microscopy (SEM) analysis of the surface morphology of amorphous-UO 3 samples calcined at 250, 300, 350, 400, and 450°C from uranyl peroxide was performed to determine if the morphology was indicative of the synthesis route and thermal history for the samples. Thermogravimetic analysis-mass spectrometry (TGA-MS) and differential scanning calorimetry (DSC) were used to correlate transitions in the calcined material to morphological transformations. The high-resolution SEM images were processed using the Morphological Analysis for Material Attribution (MAMA) software. Morphological attributes, particle area and circularity, indicated significant trends as a result of calcination temperature. The quantitative morphological analysis was able to track the process of particle fragmentation and subsequent sintering as calcination temperature was increased. At the 90% confidence interval, with 1000 segmented particles, the use of Kolmogorov-Smirnov statistical comparisons allowed discernment between all calcination temperatures for the uranyl peroxide route. Copyright © 2017 The Authors. Published by Elsevier B.V. All rights reserved.

The effect of cyclic heat treatment on the physicochemical properties of bio hydroxyapatite from bovine bone.

PubMed

Londoño-Restrepo, S M; Jeronimo-Cruz, R; Rubio-Rosas, E; Rodriguez-García, M E

2018-05-02

This paper focus on physicochemical changes in bio-hydroxyapatite (BIO-HAp) from bovine femur obtained by calcination at high temperatures: 520-620 (each 20 °C) at 7.4 °C/min and from 700 to 1100 °C (each 100 °C) at three heating rates: 7.4, 9.9, and 11.1 °C/min. BIO-HAp samples were obtained using a multi-step process: cleaning, milling, hydrothermal process, calcination in an air atmosphere, and cooling in furnace air. Inductively Couple Plasma (ICP) showed that the presence of Mg, K, S, Ba, Zn, and Na, is not affected by the annealing temperature and heating rate. While Scanning Electron Microscopy (SEM) images showed the continuous growth of the HAp crystals during the calcination process due to the coalescence phenomenon, and the Full Width at the Half Maximum for the X-ray patterns for temperatures up to 700 is affected by the annealing temperature and the heating rate. Through X-ray diffraction, thermal, and calorimetric analysis (TGA-DSC), a partial dehydroxylation of hydroxyapatite was found in samples calcined up to 900 °C for the three heating rates. Also, Ca/P molar ratio decreased for samples calcined up to 900 °C as a result of the dehydroxylation process. NaCaPO 4 , CaCO 3 , Ca 3 (PO 4 ) 2 , MgO, and Ca(H 2 PO 4 ) 2 are some phases identified by X-ray diffraction; some of them are part of the bone and others were formed during the calcination process as a function of annealing temperature and heating rate, as it is the case for MgO.

Effect of calcination temperature on the photocatalytic reduction and oxidation processes of hydrothermally synthesized titania nanotubes.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Viayan, B.; Dimitrijevic, N. M.; Rajh, T.

Titania nanotubes having diameters 8 to 12 nm and lengths of 50-300 nm were prepared using a hydrothermal method. Further, the titania nanotubes were calcined over the temperature range 200-800 C in order to enhance their photocatalytic properties by altering their morphology. The calcined titania nanotubes were characterized by using X-ray diffraction and surface area analysis and their morphological features were studied by scanning and transmission electron microscopy. Nanotubes calcined at 400 C showed the maximum extent of photocatalyitc reduction of carbon dioxide to methane, whereas samples calcined at 600 C produced maximum photocatalytic oxidation of acetaldehyde. Electron paramagnetic resonancemore » (EPR) spectroscopy was used to interrogate the effects of nanotube structure on the charge separation and trapping as a function of calcination temperature. EPR results indicated that undercoordinated titania sites are associated with maximum CO{sub 2} reduction occurring in nanotubes calcined at 400 C. Despite the collapse of the nantube structure to form nanorods and the concomitant loss of surface area, the enhanced charge separation associated with increased crystallinity promoted high rates of oxidation of acetaldehyde in titania materials calcined at 600 C. These results illustrate that calcination temperature allows us to tune the morphological and surface features of the titania nanostructures for particular photocatalytic reactions.« less

Characterization of Offgas Generated During Calcination of Incinerator Ash Surrogates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wigent, H.L.; Vienna, J.D.; Darab, J.G.

1999-01-28

The Pacific Northwest National Laboratory (PNNL), in cooperation with the Los Alamos National Laboratory (LANL) and Safe Sites of Colorado (SSOC), developed a recommended flowsheet for the processing of plutonium-bearing incinerator ash stored at the Rocky Flats Environmental Technology Site (RFETS) (Lucy et al. 1998). This flowsheet involves a calcination pretreatment step, the purpose of which is to remove carbonaceous material from the incinerator ash. Removal of this material reduced the probability of process upsets, improved product quality, and increases ash waste loading. As part of the continued development of the recommended flowsheet, PNNL performed a series of tests tomore » characterize the offgas generated during the calcination process.« less

Hydrogenation of furfural at the dynamic Cu surface of CuOCeO2/Al2O3 in vapor phase packed bed reactor

USDA-ARS?s Scientific Manuscript database

The hydrogenation of furfural to furfuryl alcohol over a CuOCeO2/'-Al2O3 catalyst in a flow reactor is reported. The catalyst was prepared by the wet impregnation of Cu onto a CeO2/'-Al2O3 precursor. The calcined catalyst was then treated with HNO3 to remove surface CuO resulting in a mixed CuCe oxi...

Durable zinc oxide-containing sorbents for coal gas desulfurization

DOEpatents

Siriwardane, Ranjani V.

1996-01-01

Durable zinc-oxide containing sorbent pellets for removing hydrogen sulfide from a gas stream at an elevated temperature are made up to contain titania as a diluent, high-surface-area silica gel, and a binder. These materials are mixed, moistened, and formed into pellets, which are then dried and calcined. The resulting pellets undergo repeated cycles of sulfidation and regeneration without loss of reactivity and without mechanical degradation. Regeneration of the pellets is carried out by contacting the bed with an oxidizing gas mixture.

SO2 retention by reactivated CaO-based sorbent from multiple CO2 capture cycles.

PubMed

Manovic, Vasilije; Anthony, Edward J

2007-06-15

This paper examines the reactivation of spent sorbent, produced from multiple CO2 capture cycles, for use in SO2 capture. CaO-based sorbent samples were obtained from Kelly Rock limestone using three particle size ranges, each containing different impurities levels. Using a thermogravimetric analyzer (TGA), the sulfation behavior of partially sulfated and unsulfated samples obtained after multiple calcination-carbonation cycles in a tube furnace (TF), following steam reactivation in a pressurized reactor, is examined. In addition, samples calcined/sintered under different conditions after hydration are also examined. The results show that suitably treated spent sorbent has better sulfation characteristics than that of the original sorbent. Thus for example, after 2 h sulfation, > 80% of the CaO was sulfated. In addition, the sorbent showed significant activity even after 4 h when > 95% CaO was sulfated. The results were confirmed by X-ray diffraction (XRD) analysis, which showed that, by the end of the sulfation process, samples contained CaSO4 with only traces of unreacted CaO. The superior behavior of spent reactivated sorbent appears to be due to swelling of the sorbent particles during steam hydration. This enables the development of a more suitable pore surface area and pore volume distribution for sulfation, and this has been confirmed by N2 adsorption-desorption isotherms and the Barrett-Joyner-Halenda (BJH) method. The surface area morphology of sorbent after reactivation was examined by scanning electron microscopy (SEM). Ca(OH)2 crystals were seen, which displayed their regular shape, and their elemental composition was confirmed by energy-dispersive X-ray (EDX) analysis. The improved characteristics of spent reactivated sorbent in comparison to the original and to the sorbent calcined under different conditions and hydrated indicate the beneficial effect of CO2 cycles on sorbent reactivation and subsequent sulfation. These results allow us to propose a new process for the use of CaO-based sorbent in fluidized bed combustion (FBC) systems, which incorporates CO2 capture, sorbent reactivation, and SO2 retention.

Process and equipment development for hot isostatic pressing treatability study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bateman, Ken; Wahlquist, Dennis; Malewitz, Tim

2015-03-01

Battelle Energy Alliance (BEA), LLC, has developed processes and equipment for a pilot-scale hot isostatic pressing (HIP) treatability study to stabilize and volume reduce radioactive calcine stored at Idaho National Laboratory (INL). In 2009, the U. S. Department of Energy signed a Record of Decision with the state of Idaho selecting HIP technology as the method to treat 5,800 yd^3 (4,400 m^3) of granular zirconia and alumina calcine produced between 1953 and 1992 as a waste byproduct of spent nuclear fuel reprocessing. Since the 1990s, a variety of radioactive and hazardous waste forms have been remotely treated using HIP withinmore » INL hot cells. To execute the remote process at INL, waste is loaded into a stainless-steel or aluminum can, which is evacuated, sealed, and placed into a HIP furnace. The HIP simultaneously heats and pressurizes the waste, reducing its volume and increasing its durability. Two 1 gal cans of calcine waste currently stored in a shielded cask were identified as candidate materials for a treatability study involving the HIP process. Equipment and materials for cask-handling and calcine transfer into INL hot cells, as well as remotely operated equipment for waste can opening, particle sizing, material blending, and HIP can loading have been designed and successfully tested. These results demonstrate BEA’s readiness for treatment of INL calcine.« less

Effects of biomass reducing agent on magnetic properties and phase transformation of Baotou low-grade limonite during magnetizing-roasting

PubMed Central

Guo, Wen chao; Luo, Hui juan; Gong, Zhi jun; Li, Bao wei; Wu, Wen fei

2017-01-01

Biomass was used as reducing agent to roast the Baotou low-grade limonite in a high temperature vacuum atmosphere furnace. The effect of calcination temperature, time and ratio of reducing agent on the magnetic properties of calcined ore was studied by VSM. The phase and microstructure changes of limonite before and after calcination were analyzed by XRD and SEM. The results show that in the roasting process the phase transition process of the ferrous material in limonite is first dehydrated at high temperature to formα-Fe2O3, and then it is converted into Fe3O4 by the reduction of biomass. With the increase of calcination temperature, the magnetic properties of the calcined ore first increase and then decrease. When the temperature is higher than 650°C, Fe3O4 will become Fe2SiO4, resulting in reduced the magnetic material in calcined ore and the magnetic weakened. The best magnetization effect was obtained when the roasting temperature is 550°C, the percentage of biomass was 15% and the roasting time was 30min. The saturation magnetization can reach 60.13emu·g-1, the recovery of iron was 72% and the grade of iron was 58%. PMID:29040307

Effects of biomass reducing agent on magnetic properties and phase transformation of Baotou low-grade limonite during magnetizing-roasting.

PubMed

Zhang, Kai; Chen, Xiu Li; Guo, Wen Chao; Luo, Hui Juan; Gong, Zhi Jun; Li, Bao Wei; Wu, Wen Fei

2017-01-01

Biomass was used as reducing agent to roast the Baotou low-grade limonite in a high temperature vacuum atmosphere furnace. The effect of calcination temperature, time and ratio of reducing agent on the magnetic properties of calcined ore was studied by VSM. The phase and microstructure changes of limonite before and after calcination were analyzed by XRD and SEM. The results show that in the roasting process the phase transition process of the ferrous material in limonite is first dehydrated at high temperature to formα-Fe2O3, and then it is converted into Fe3O4 by the reduction of biomass. With the increase of calcination temperature, the magnetic properties of the calcined ore first increase and then decrease. When the temperature is higher than 650°C, Fe3O4 will become Fe2SiO4, resulting in reduced the magnetic material in calcined ore and the magnetic weakened. The best magnetization effect was obtained when the roasting temperature is 550°C, the percentage of biomass was 15% and the roasting time was 30min. The saturation magnetization can reach 60.13emu·g-1, the recovery of iron was 72% and the grade of iron was 58%.

Human health risk characterization of petroleum coke calcining facility emissions.

PubMed

Singh, Davinderjit; Johnson, Giffe T; Harbison, Raymond D

2015-12-01

Calcining processes including handling and storage of raw petroleum coke may result in Particulate Matter (PM) and gaseous emissions. Concerns have been raised over the potential association between particulate and aerosol pollution and adverse respiratory health effects including decrements in lung function. This risk characterization evaluated the exposure concentrations of ambient air pollutants including PM10 and gaseous pollutants from a petroleum coke calciner facility. The ambient air pollutant levels were collected through monitors installed at multiple locations in the vicinity of the facility. The measured and modeled particulate levels in ambient air from the calciner facility were compared to standards protective of public health. The results indicated that exposure levels were, on occasions at sites farther from the facility, higher than the public health limit of 150 μg/m(3) 24-h average for PM10. However, the carbon fraction demonstrated that the contribution from the calciner facility was de minimis. Exposure levels of the modeled SO2, CO, NOx and PM10 concentrations were also below public health air quality standards. These results demonstrate that emissions from calcining processes involving petroleum coke, at facilities that are well controlled, are below regulatory standards and are not expected to produce a public health risk. Copyright © 2015 Elsevier Inc. All rights reserved.

Influence of calcinated and non calcinated nanobioglass particles on hardness and bioactivity of sol-gel-derived TiO2-SiO2 nano composite coatings on stainless steel substrates.

PubMed

Dadash, Mohammad Saleh; Karbasi, Saeed; Esfahani, Mojtaba Nasr; Ebrahimi, Mohammad Reza; Vali, Hojatollah

2011-04-01

Thick films of calcinated and non calcinated nanobioglass (NBG)-titania composite coatings were prepared on stainless steel substrates by alkoxide sol-gel process. Dip-coating method was used for the films preparation. The morphology, structure and composition of the nano composite films were evaluated using environmental scanning electron microscope, X-ray diffraction and Fourier transform infrared spectroscope. The SEM investigation results showed that prepared thick NBG-titania films are smooth and free of macrocracking, fracture or flaking. The grain size of these films was uniform and nano scale (50-60 nm) which confirmed with TEM. Also FTIR confirmed the presence of Si-O-Si bands on the calcinated NBG-titania films. The hardness of the prepared films (TiO(2)-calcinated NBG and TiO(2)-Non calcinated NBG) was compared by using micro hardness test method. The results verified that the presence of calcinated NBG particles in NBG-titania composite enhanced gradually the mechanical data of the prepared films. The in vitro bioactivity of these films was discussed based on the analysis of the variations of Ca and P concentrations in the simulated body fluid (SBF) and their surface morphologies against immersion time. Surface morphology and Si-O-Si bands were found to be of great importance with respect to the bioactivity of the studied films. The results showed that calcinated NBG-titania films have better bioactivity than non calcinated NBG-titania films.

Surface hydrophobicity and acidity effect on alumina catalyst in catalytic methanol dehydration reaction

PubMed Central

Osman, Ahmed I; Thompson, Jillian; Halawy, Samih A; Mohamed, Mohamed A

2017-01-01

Abstract BACKGROUND Methanol to dimethyl ether (MTD) is considered one of the main routes for the production of clean bio‐fuel. The effect of copper loading on the catalytic performance of different phases of alumina that formed by calcination at two different temperatures was examined for the dehydration of methanol to dimethyl ether (DME). RESULTS A range of Cu loadings of (1, 2, 4, 6, 10 and 15% Cu wt/wt) on Al2O3 calcined at 350 and 550 °C were prepared and characterized by TGA, XRD, BET, NH3‐TPD, TEM, H2‐TPR, SEM, EDX, XPS and DRIFT‐Pyridine techniques. The prepared catalysts were used in a fixed bed reactor under reaction conditions in which the temperature ranged from 180–300 °C with weight hourly space velocity (WHSV) = 12.1 h‐1. It was observed that all catalysts calcined at 550 °C (γ‐Al2O3 support phase) exhibited higher activity than those calcined at 350 °C (γ‐AlOOH), and this is due to the phase support change. Furthermore, the optimum Cu loading was found to be 6% Cu/γ‐Al2O3 with this catalyst also showing a high degree of stability under steady state conditions and this is attributed to the enhancement in surface acidity and hydrophobicity. CONCLUSION The addition of copper to the support improved the catalyst properties and activity. For all the copper modified catalysts, the optimum catalyst with high degree of activity and stability was 6% copper loaded on gamma alumina. © 2017 The Authors. Journal of Chemical Technology & Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry. PMID:29200585

Boron sorption from aqueous solution by hydrotalcite and its preliminary application in geothermal water deboronation.

PubMed

Guo, Qinghai; Zhang, Yin; Cao, Yaowu; Wang, Yanxin; Yan, Weide

2013-11-01

Hydrotalcite and its calcination product were used to treat pure water spiked with various concentrations of boron and geothermal water containing boron as a major undesirable element. The kinetics process of boron sorption by uncalcined hydrotalcite is controlled by the diffusion of boron from bulk solution to sorbent-solution boundary film and its exchange with interlayer chloride of hydrotalcite, whereas the removal rate of boron by calcined hydrotalcite rests with the restoration process of its layered structure. The results of isotherm sorption experiments reveal that calcined hydrotalcite generally has much stronger ability to lower solution boron concentration than uncalcined hydrotalcite. The combination of adsorption of boron on the residue of MgO-Al2O3 solid solution and intercalation of boron into the reconstructed hydrotalcite structure due to "structural memory effect" is the basic mechanism based on which the greater boron removal by calcined hydrotalcite was achieved. As 15 geothermal water samples were used to test the deboronation ability of calcined hydrotalcite at 65 °C, much lower boron removal efficiencies were observed. The competitive sorption of the other anions in geothermal water, such as HCO3-, SO4(2-), and F-, is the reason why calcined hydrotalcite could not remove boron from geothermal water as effectively as from pure boron solution. However, boron removal percents ranging from 89.3 to 99.0% could be obtained if 50 times of sorbent were added to the geothermal water samples. Calcined hydrotalcite is a good candidate for deboronation of geothermal water.

Thermal and structural characterization of synthetic and natural nanocrystalline hydroxyapatite.

PubMed

Sofronia, Ancuta M; Baies, Radu; Anghel, Elena M; Marinescu, Cornelia A; Tanasescu, Speranta

2014-10-01

The aim of this work was to study the thermal stability on heating and to obtain the processing parameters of synthetic and bone-derived hydroxyapatite over temperatures between room temperature and 1400°C by thermal analysis (thermogravimetry (TG)/differential scanning calorimetry (DSC) and thermo-mechanical analysis-TMA). Structural and surface modifications related to samples origin and calcination temperature were investigated by Fourier transformed infrared (FTIR) and Raman spectroscopy, X-ray diffraction (XRD) and BET method. FTIR spectra indicated that the organic constituents and carbonate are no longer present in the natural sample calcined at 800°C. Raman spectra highlighted the decomposition products of the hydroxyapatite. The calcination treatment modifies the processes kinetics of the synthetic samples, being able to isolate lattice water desorption processes of decarbonization and the dehydroxylation processes. Shrinkage of calcined synthetic sample increases by 10% compared to uncalcined synthetic powder. From the TMA correlated with TG analysis and heat capacity data it can be concluded that sintering temperature of the synthetic samples should be chosen in the temperature range of the onset of dehydroxylation and the temperature at which oxyapatite decomposition begins. Copyright © 2014 Elsevier B.V. All rights reserved.

Synthesis and physical characterization of γ-Fe2O3 and (α+γ)-Fe2O3 nanoparticles

NASA Astrophysics Data System (ADS)

Bhavani, P.; Reddy, N. Ramamanohar; Reddy, I. Venkata Subba

2017-01-01

Magnetic nanoparticles were synthesized at different hydrothermal temperatures (HT; 100, 130, 160 and 190 °C) by using a facile hydrothermal route combined with a subsequent calcination process. The calcined materials were analyzed for phase, microstructure, and magnetic and dielectric properties through different characterization techniques. The structural analyses revealed that the material prepared at a HT of 100 °C and sequentially calcined at 300 °C for 3 h showed a high degree of the maghemite structure. On the other hand calcined materials showed a small additional peak belonging to the hematite structure. FESEM micrographs of the materials calcined at HT, of 100 °C and 190 °C showed spherical-like nanoparticles with diameters in range 30 - 54 nm. Materials prepared at a HT of 160 °C followed by calcination at 300 °C for 3 h exhibited the highest saturation magnetization, Ms = 67 emu/g, with a lower coercivity; all materials were in a single domain state. A high dielectric constant (105.54) was observed for the calcined material that had been prepared at a HT of 130 °C. The dielectric properties of synthesized materials showed an almost frequency-independent behavior.

Development of a low-pressure materials pre-treatment process for improved energy efficiency

NASA Astrophysics Data System (ADS)

Lee, Kwanghee; You, Byung Don

2017-09-01

Low pressure materials pre-treatment process has been developed as an alternative to the existing high-temperature sludge drying, limestone calcination, and limonite dehydroxylation. Using the thermodynamic equilibrium relationship between temperature and pressure represented by the Clausius-Clapeyron equation, the operational temperature of these reactions could be lowered at reduced pressure for increased energy efficiency. For industrial sludge drying, the evaporation rate was controlled by interfacial kinetics showing a constant rate with time and significant acceleration in the reaction could be observed with reduced pressure. At this modified reaction rate under low pressure, the rate was also partially controlled by mass transfer. Temperature of limestone calcination was lowered, but the reaction was limited at the calculated equilibrium temperature of the Clausius-Clapeyron equation and slightly higher temperatures were required. The energy consumption during limestone calcination and limonite dehydroxylation were evaluated, where lower processing pressures could enhance the energy efficiency for limestone calcination, but limonite dehydroxylation could not achieve energy-savings due to the greater power consumption of the vacuum pump under lower pressure and reduced temperatures.

Preparation and electrochemical properties of NiO-Co3O4 composite as electrode materials for supercapacitors

NASA Astrophysics Data System (ADS)

Wang, X. W.; Zheng, D. L.; Yang, P. Z.; Wang, X. E.; Zhu, Q. Q.; Ma, P. F.; Sun, L. Y.

2017-01-01

The precursor of NiO-Co3O4 composites was synthesized via a simple hydrothermal process. After that, the precursor was calcined at 300 °C for 3 h to obtain the composite powders. The powders calcined at 300 °C showed amorphous, and the powders calcined at 400 °C and 500 °C for comparison showed the composite phase of NiO and Co3O4. The composite products showed a microstructure of micro-spheres. For the samples calcined at 300 °C for 3 h, the specific capacitance reached 801 F g-1 at a current density of 1 A g-1.

Attrition resistant fluidizable reforming catalyst

DOEpatents

Parent, Yves O [Golden, CO; Magrini, Kim [Golden, CO; Landin, Steven M [Conifer, CO; Ritland, Marcus A [Palm Beach Shores, FL

2011-03-29

A method of preparing a steam reforming catalyst characterized by improved resistance to attrition loss when used for cracking, reforming, water gas shift and gasification reactions on feedstock in a fluidized bed reactor, comprising: fabricating the ceramic support particle, coating a ceramic support by adding an aqueous solution of a precursor salt of a metal selected from the group consisting of Ni, Pt, Pd, Ru, Rh, Cr, Co, Mn, Mg, K, La and Fe and mixtures thereof to the ceramic support and calcining the coated ceramic in air to convert the metal salts to metal oxides.

Calcined polyaniline-iron composite as a high efficient cathodic catalyst in microbial fuel cells.

PubMed

Lai, Bin; Wang, Peng; Li, Haoran; Du, Zhuwei; Wang, Lijuan; Bi, Sichao

2013-03-01

A new type of carbon-nitrogen-metal catalyst, PANI-Fe-C, was synthesized by calcination process. According to the results of FT-IR and XPS analysis, polyaniline chain was broken by calcination. Small nitrogen-contained molecular fragments were gasified during calcination process, while the remaining nitrogen atoms were enchased in the new produced multiple carbon rings by C-N and CN bonds and performed as the catalytic active sites and the covalent centers for soluble iron components. Calculated from the polarization curves, a maximum power density of 10.17W/m(3) for the MFC with the synthetic catalyst was obtained, which was slightly higher than the MFC with Pt/C catalyst of 9.56W/m(3). All the results obtained in this paper proved that the newly synthetic nitrogen-carbon-metal catalyst would be a potential alternative to the expensive Pt/C catalyst in the field of MFC. Copyright © 2012 Elsevier Ltd. All rights reserved.

Assessment of the use of red mud as a catalyst for photodegradation of bisphenol A in wastewater treatment.

PubMed

Busto, Raquel Vieira; Gonçalves, Maraisa; Coelho, Lúcia Helena Gomes

2016-09-01

This study aimed to investigate the use of red mud (RM) - a byproduct of aluminum production, as a photocatalyst, which was characterized physical-chemically and used in the photodegradation of the target compound bisphenol A (BPA). Chemical processing was performed in the RM (acid treatment, chemical reduction and calcination) to verify the most active catalyst. From the results obtained, a complete degradation kinetics of BPA was carried out using a synthetic matrix (BPA in deionized water) and a real matrix (BPA in wastewater) using natural RM/calcined and TiO 2 for comparison. The results indicated the potential use of the RM/calcined, which was able to degrade between 88 and 100% of the pollutant in a synthetic sample. Tests on a real effluent sample resulted in degradation rates that ranged from 59 to 100% with chemical oxygen demand reductions of up to 23% using natural RM/calcined in comparison to TiO 2 . The blank system (irradiation of the solution without the use of a photocatalyst) and the natural RM/calcined one, resulted in reductions of the toxicity in the effluent sample (measured by EC 20 using the marine bacteria Vibrio fischeri) of about 12 times, whereas the same treatment using TiO 2 resulted in a toxicity reduction of only seven times. Within these results, the RM/calcined showed potential to be used in wastewater treatment in polishing processes.

The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Montagnaro, Fabio; Salatino, Piero; Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli

2010-04-15

The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination.more » This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)« less

40 CFR 98.314 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... requirements. (a) You must measure your consumption of calcined petroleum coke using plant instruments used for accounting purposes including direct measurement weighing the petroleum coke fed into your process (by belt... used to ensure the accuracy of monthly calcined petroleum coke consumption measurements. (c) You must...

40 CFR 98.314 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2013 CFR

2013-07-01

... requirements. (a) You must measure your consumption of calcined petroleum coke using plant instruments used for accounting purposes including direct measurement weighing the petroleum coke fed into your process (by belt... used to ensure the accuracy of monthly calcined petroleum coke consumption measurements. (c) You must...

40 CFR 98.314 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

... requirements. (a) You must measure your consumption of calcined petroleum coke using plant instruments used for accounting purposes including direct measurement weighing the petroleum coke fed into your process (by belt... used to ensure the accuracy of monthly calcined petroleum coke consumption measurements. (c) You must...

40 CFR 98.314 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2014 CFR

2014-07-01

... requirements. (a) You must measure your consumption of calcined petroleum coke using plant instruments used for accounting purposes including direct measurement weighing the petroleum coke fed into your process (by belt... used to ensure the accuracy of monthly calcined petroleum coke consumption measurements. (c) You must...

Synthesis of alumina ceramic encapsulation for self-healing materials on thermal barrier coating

NASA Astrophysics Data System (ADS)

Golim, O. P.; Prastomo, N.; Izzudin, H.; Hastuty, S.; Sundawa, R.; Sugiarti, E.; Thosin, K. A. Z.

2018-03-01

Durability of Thermal Barrier Coating or TBC can be optimized by inducing Self-Healing capabilities with intermetallic materials MoSi2. Nevertheless, high temperature operation causes the self-healing materials to become oxidized and lose its healing capabilities. Therefore, a method to introduce ceramic encapsulation for MoSi2 is needed to protect it from early oxidation. The encapsulation process is synthesized through a simple precipitation method with colloidal aluminum hydroxide as precursor and variations on calcination process. Semi-quantitative analysis on the synthesized sample is done by using X-ray diffraction (XRD) method. Meanwhile, qualitative analysis on the morphology of the encapsulation was carried out by using Scanning Electron Microscope (SEM) and Field Emission Scanning Electron Microscope (FESEM) equipped with dual Focus Ion Beam (FIB). The result of the experiment shows that calcination process significantly affects the final characteristic of encapsulation. The optimum encapsulation process was synthesized by colloidal aluminum hydroxide as a precursor, with a double step calcination process in low pressure until 900 °C.

Formation and morphology of Zn(2)Ti(3)O(8) powders using hydrothermal process without dispersant agent or mineralizer.

PubMed

Wang, Cheng-Li; Hwang, Weng-Sing; Chang, Kuo-Ming; Ko, Horng-Huey; Hsi, Chi-Shiung; Huang, Hong-Hsin; Wang, Moo-Chin

2011-01-28

Synthesis of Zn(2)Ti(3)O(8) powders for attenuating UVA using TiCl(4), Zn(NO(3))(2)·6H(2)O and NH(4)OH as precursor materials by hydrothermal process has been investigated. The X-ray diffractometry (XRD) results show the phases of ZnO, anatase TiO(2) and Zn(2)Ti(3)O(8) coexisted when the zinc titanate powders were calcined at 600 °C for 1 h. When calcined at 900 °C for 1 h, the XRD results reveal the existence of ZnO, Zn(2)TiO(4), rutile TiO(2) and ZnTiO(3). Scanning electron microscope (SEM) observations show extensive large agglomeration in the samples. Transmission electron microscope (TEM) and electron diffraction (ED) examination results indicate that ZnTiO(3) crystallites formed with a size of about 5 nm on the matrix of plate-like ZnO when calcined at 700 °C for 1 h. The calcination samples have acceptable absorbance at a wavelength of 400 nm, indicating that the zinc titanate precursor powders calcined at 700 °C for 1 h can be used as an UVA-attenuating agent.

Formation and Morphology of Zn2Ti3O8 Powders Using Hydrothermal Process without Dispersant Agent or Mineralizer

PubMed Central

Wang, Cheng-Li; Hwang, Weng-Sing; Chang, Kuo-Ming; Ko, Horng-Huey; Hsi, Chi-Shiung; Huang, Hong-Hsin; Wang, Moo-Chin

2011-01-01

Synthesis of Zn2Ti3O8 powders for attenuating UVA using TiCl4, Zn(NO3)2·6H2O and NH4OH as precursor materials by hydrothermal process has been investigated. The X-ray diffractometry (XRD) results show the phases of ZnO, anatase TiO2 and Zn2Ti3O8 coexisted when the zinc titanate powders were calcined at 600 °C for 1 h. When calcined at 900 °C for 1 h, the XRD results reveal the existence of ZnO, Zn2TiO4, rutile TiO2 and ZnTiO3. Scanning electron microscope (SEM) observations show extensive large agglomeration in the samples. Transmission electron microscope (TEM) and electron diffraction (ED) examination results indicate that ZnTiO3 crystallites formed with a size of about 5 nm on the matrix of plate-like ZnO when calcined at 700 °C for 1 h. The calcination samples have acceptable absorbance at a wavelength of 400 nm, indicating that the zinc titanate precursor powders calcined at 700 °C for 1 h can be used as an UVA-attenuating agent. PMID:21541035

40 CFR 98.317 - Records that must be retained.

Code of Federal Regulations, 2012 CFR

2012-07-01

... coke purchases. (2) Annual operating hours for each titanium dioxide process line. (b) If a CEMS is not... paraghraph: (1) Records of all calcined petroleum coke purchases (tons). (2) Records of all analyses and... content of consumed calcined petroleum coke (percent by weight expressed as a decimal fraction). (4...

40 CFR 98.317 - Records that must be retained.

Code of Federal Regulations, 2011 CFR

2011-07-01

... coke purchases. (2) Annual operating hours for each titanium dioxide process line. (b) If a CEMS is not... paraghraph: (1) Records of all calcined petroleum coke purchases (tons). (2) Records of all analyses and... content of consumed calcined petroleum coke (percent by weight expressed as a decimal fraction). (4...

40 CFR 98.317 - Records that must be retained.

Code of Federal Regulations, 2014 CFR

2014-07-01

... coke purchases. (2) Annual operating hours for each titanium dioxide process line. (b) If a CEMS is not... paraghraph: (1) Records of all calcined petroleum coke purchases (tons). (2) Records of all analyses and... content of consumed calcined petroleum coke (percent by weight expressed as a decimal fraction). (4...

40 CFR 98.317 - Records that must be retained.

Code of Federal Regulations, 2013 CFR

2013-07-01

... coke purchases. (2) Annual operating hours for each titanium dioxide process line. (b) If a CEMS is not... paraghraph: (1) Records of all calcined petroleum coke purchases (tons). (2) Records of all analyses and... content of consumed calcined petroleum coke (percent by weight expressed as a decimal fraction). (4...

UNIT OPERATIONS SECTION MONTHLY PROGRESS REPORT, OCTOBER 1961

DOE Office of Scientific and Technical Information (OSTI.GOV)

Whatley, M.E.; Haas, P.A.; Horton, R.W.

1962-04-01

Additional runs were made in the 6-in.-dia. separation column. The kinetics of the methane --copper oxide reaction was investigated in deep bed tests. The work on the development of the shear included a satisfactory method of ng, preliminary test of an outer gag faced with rubber, and a metallic inner gsg contoured to the shape of a sheared assembly. The mechanical dejacketing of the SRE Core I fuel, NaK-bonded, stainless steel-clad uranium slugs, was successfully completed. The effective therrnal conductivity of a packed bed of 0.023-in. steel shot was approximately 0.33 Btu/hr- deg Fft at 200 deg F. Flow capacitymore » for the compound extraction scrub column equipped with sieve plates (0.125-in.-dia. was determined. Average waste calcination rates for Purex were higher by a factor of 1.5 to 2.0 than rates for TBP-25. (auth)« less

Relationships Between Smelter Grade Alumina Characteristics and Strength Determined by Nanoindentation and Ultrasound-Mediated Particle Breakage

NASA Astrophysics Data System (ADS)

Wijayaratne, Hasini; McIntosh, Grant; Hyland, Margaret; Perander, Linus; Metson, James

2017-06-01

The mechanical strength of smelter grade alumina (SGA) is of considerable practical significance for the aluminum reduction process. Attrition of alumina during transportation and handling generates an increased level of fines. This results in generation of dust, poor flow properties, and silo segregation that interfere with alumina feeding systems. These lead to process instabilities which in turn result in current efficiency losses that are costly. Here we are concerned with developing a fundamental understanding of SGA strength in terms of its microstructure. Nanoindentation and ultrasound-mediated particle breakage tests have been conducted to study the strength. Strength of SGA samples both industry calcined and laboratory prepared, decrease with increasing α-alumina (corundum) content contrary to expectation. The reducing strength of alumina with increasing degree of calcination is attributed to the development of a macroporous and abrasion-prone microstructure resulting from the `pseudomorphic' transformation of precursor gibbsite during the calcination process.

Solution-Based Approaches to Fabrication of YBa2Cu3O7-δ (YBCO): Precursors of Tri-Fluoroacetate (TFA) and Nanoparticle Colloids

NASA Astrophysics Data System (ADS)

Mukhopadhyay, S. M.; Su, J.; Chintamaneni, V.

2007-10-01

Detailed investigation of superconducting films of YBa2Cu3O7-δ (YBCO) prepared from solution-based precursors have been performed. Two precursors have been compared in this study: the presently used trifluoroacetate (TFA) solution and a recently developed colloidal suspension containing nanoparticles of mixed oxide. Detailed analyses of the evolution of microstructure and chemistry of the films have been performed, and process parameters have been correlated with final superconducting properties. Both films need two heating steps: a low temperature calcination and a higher temperature crystallization step. For TFA films, it was seen that the heating rate during calcination needs to be carefully optimized and is expected to be slow. For the alternate process using a nanoparticle precursor, a significantly faster calcination rate is possible. In the TFA process, the Ba ion remains as fluoride and the Y remains as oxyfluoride after calcination. This implies that, during the final crystallization stage to form YBCO, fluorine-containing gases will evolve, resulting in residual porosity. On the other hand, the film from the nanoparticle process is almost fully oxidized after calcination. Therefore, no gases evolve at the final firing (crystallization) stage, and the film has much lower porosity. The superconducting properties of both types of films are adequate, but the nanoparticle films appear to have persistently higher J c values. Moreover, they show improved flux pinning in higher magnetic fields, probably due to nanoscale precipitates of a Cu-rich phase. In addition, the nanocolloid films seem to show additionally enhanced flux pinning when doped with minute amounts of second phase precipitates. It therefore appears that, whereas the TFA process is already quite successful, the newly developed nanoparticle process has significant scope for additional improvement. It can be scaled-up with ease, and can be easily adapted to incorporate nanoscale flux pinning defects for in-field performance.

Use of Raman spectroscopy to assess the efficiency of MgAl mixed oxides in removing cyanide from aqueous solutions

NASA Astrophysics Data System (ADS)

Cosano, Daniel; Esquinas, Carlos; Jiménez-Sanchidrián, César; Ruiz, José Rafael

2016-02-01

Calcining magnesium/aluminium layered double hydroxides (Mg/Al LDHs) at 450 °C provides excellent sorbents for removing cyanide from aqueous solutions. The process is based on the "memory effect" of LDHs; thus, rehydrating a calcined LDH in an aqueous solution restores its initial structure. The process, which conforms to a first-order kinetics, was examined by Raman spectroscopy. The metal ratio of the LDH was found to have a crucial influence on the adsorption capacity of the resulting mixed oxide. In this work, Raman spectroscopy was for the first time use to monitor the adsorption process. Based on the results, this technique is an effective, expeditious choice for the intended purpose and affords in situ monitoring of the adsorption process. The target solids were characterized by using various instrumental techniques including X-ray diffraction spectroscopy, which confirmed the layered structure of the LDHs and the periclase-like structure of the mixed oxides obtained by calcination.

Recycling Lithium Carbonate/Lithium Hydroxide Waste

NASA Technical Reports Server (NTRS)

Flowers, J.; Flowers, J.

1983-01-01

Hazardous waste disposal problem eliminated by regeneration. Li2CO3/ LiOH recycling process relies on low solubility of alkali carbonates in corresponding hydroxides. Li2CO3 precipitate calcined to LI2O, then rehydrated LiOH. Regeneration eliminates need to dispose caustic waste and uses less energy than simple calcination of entire waste mass.

Vitrification of radioactive high-level waste by spray calcination and in-can melting

NASA Astrophysics Data System (ADS)

Hanson, M. S.; Bjorklund, W. J.

1980-07-01

After several nonradioactive test runs, radioactive waste from the processing of 1.5 t of spent, light water reactor fuel was successfully concentrated, dried and converted to a vitreous product. A total of 97 L of waste glass (in two stainless steel canisters) was produced. The spray calcination process coupled to the in-can melting process, as developed at Pacific Northwest Labortory, was used to vitrify the waste. An effluent system consisting of a variety of condensation of scrubbing steps more than adequately decontaminated the process off gas before it was released to the atmosphere.

Evolution of catalytic activity of Au-Ag bimetallic nanoparticles on mesoporous support for CO oxidation.

PubMed

Wang, Ai-Qin; Chang, Chun-Ming; Mou, Chung-Yuan

2005-10-13

We report a novel Au-Ag alloy catalyst supported on mesoporous aluminosilicate Au-Ag@MCM prepared by a one-pot synthesis procedure, which is very active for low-temperature CO oxidation. The activity was highly dependent on the hydrogen pretreatment conditions. Reduction at 550-650 degrees C led to high activity at room temperature, whereas as-synthesized or calcined samples did not show any activity at the same temperature. Using various characterization techniques, such as XRD, UV-vis, XPS, and EXAFS, we elucidated the structure and surface composition change during calcination and the reduction process. The XRD patterns show that particle size increased only during the calcination process on those Ag-containing samples. XPS and EXAFS data demonstrate that calcination led to complete phase segregation of the Au-Ag alloy and the catalyst surface is greatly enriched with AgBr after the calcination process. However, subsequent reduction treatment removed Br- completely and the Au-Ag alloy was formed again. The surface composition of the reduced Au-Ag@MCM (nominal Au/Ag = 3/1) was more enriched with Ag, with the surface Au/Ag ratio being 0.75. ESR spectra show that superoxides are formed on the surface of the catalyst and its intensity change correlates well with the trend of catalytic activity. A DFT calculation shows that CO and O2 coadsorption on neighboring sites on the Au-Ag alloy was stronger than that on either Au or Ag. The strong synergism in the coadsorption of CO and O2 on the Au-Ag nanoparticle can thus explain the observed synergetic effect in catalysis.

The effect of heat treatment on superhydrophilicity of TiO2 nano thin films

NASA Astrophysics Data System (ADS)

Ashkarran, A. A.; Mohammadizadeh, M. R.

2007-11-01

TiO2 thin films were synthesized by the sol-gel method and spin coating process. The calcination temperature was changed from 100 to 550°C. XRD patterns show increasing the content of polycrystalline anatase phase with increasing the calcination temperature. The AFM results indicate granular morphology of the films, which particle size changes from 22 to 166nm by increasing the calcination temperature. The RBS, EDX and Raman spectroscopy of the films show the ratio of Ti:O ~0.5, and diffusion of sodium ions from substrate into the layer, by increasing the calcination temperature. The UV-vis spectroscopy of the films indicates a red shift by increasing the calcination temperature. The contact angle meter experiment shows that superhydrophilicity of the films depends on the formation of anatase crystal structure and diffused sodium content from substrate to the layer. The best hydrophilicity property was observed at 450°C calcination temperature, where the film is converted to a superhydrophilic surface after 10min under 2mW/cm2 UV irradiation. Water droplet on TiO2 thin film on Si(111), Si(100), and quartz substrates is spread to smaller angles rather than glass and polycrystalline Si substrates under UV irradiation.

Effects of Coke Calcination Level on Pore Structure in Carbon Anodes

NASA Astrophysics Data System (ADS)

Fang, Ning; Xue, Jilai; Lang, Guanghui; Bao, Chongai; Gao, Shoulei

2016-02-01

Effects of coke calcination levels on pore structure of carbon anodes have been investigated. Bench anodes were prepared by 3 types of cokes with 4 calcination temperatures (800°C, 900°C, 1000°C and 1100°C). The cokes and anodes were characterized using hydrostatic method, air permeability determination, mercury porosimetry, image analysis and confocal microscopy (CSLM). The cokes with different calcination levels are almost the same in LC values (19-20 Å) and real density (1.967-1.985 g/cm3), while the anode containing coke calcined at 900°C has the lowest open porosity and air permeability. Pore size distribution (represented by Anode H sample) can be roughly divided into two ranges: small and medium pores in diameter of 10-400 μm and large pores of 400-580 μm. For the anode containing coke calcined at 800°C, a number of long, narrow pores in the pore size range of 400-580 μm are presented among cokes particles. Formation of these elongated pores may be attributed to coke shrinkages during the anode baking process, which may develop cracking in the anode under cell operations. More small or medium rounded pores with pore size range of 10-400 μm emerge in the anodes with coke calcination temperatures of 900°C, 1000°C and 1100°C, which may be generated due to release of volatiles from the carbon anode during baking. For the anode containing coke calcined at 1100°C, it is found that many rounded pores often closely surround large coke particles, which have potential to form elongated, narrow pores.

Energy Efficient Microwave Hybrid Processing of Lime for Cement, Steel, and Glass Industries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fall, Morgana L; Yakovlev, Vadim; Sahi, Catherine

2012-02-10

In this study, the microwave materials interactions were studied through dielectric property measurements, process modeling, and lab scale microwave hybrid calcination tests. Characterization and analysis were performed to evaluate material reactions and energy usage. Processing parameters for laboratory scale and larger scale calcining experiments were developed for MAT limestone calcination. Early stage equipment design concepts were developed, with a focus on microwave post heating treatment. The retrofitting of existing rotary calcine equipment in the lime industry was assessed and found to be feasible. Ceralink sought to address some of the major barriers to the uptake of MAT identified as themore » need for (1) team approach with end users, technology partners, and equipment manufacturers, (2) modeling that incorporates kiln materials and variations to the design of industrial microwave equipment. This project has furthered the commercialization effort of MAT by working closely with an industrial lime manufacturer to educate them regarding MAT, identifying equipment manufacturer to supply microwave equipment, and developing a sophisticated MAT modeling with WPI, the university partner. MAT was shown to enhance calcining through lower energy consumption and faster reaction rates compared to conventional processing. Laboratory testing concluded that a 23% reduction in energy was possible for calcining small batches (5kg). Scale-up testing indicated that the energy savings increased as a function of load size and 36% energy savings was demonstrated (22 kg). A sophisticated model was developed which combines simultaneous microwave and conventional heating. Continued development of this modeling software could be used for larger scale calcining simulations, which would be a beneficial low-cost tool for exploring equipment design prior to actual building. Based on these findings, estimates for production scale MAT calcining benefits were calculated, assuming uptake of MAT in the US lime industry. This estimate showed that 7.3 TBTU/year could be saved, with reduction of 270 MMlbs of CO2 emissions, and $29 MM/year in economic savings. Taking into account estimates for MAT implementation in the US cement industry, an additional 39 TBTU/year, 3 Blbs of CO2 and $155 MM/year could be saved. One of the main remaining barriers to commercialization of MAT for the lime and cement industries is the sheer size of production. Through this project, it was realized that a production size MAT rotary calciner was not feasible, and a different approach was adapted. The concept of a microwave post heat section located in the upper portion of the cooler was devised and appears to be a more realistic approach for MAT implementation. Commercialization of this technology will require (1) continued pilot scale calcining demonstrations, (2) involvement of lime kiln companies, and (3) involvement of an industrial microwave equipment provider. An initial design concept for a MAT post-heat treatment section was conceived as a retrofit into the cooler sections of existing lime rotary calciners with a 1.4 year payback. Retrofitting will help spur implementation of this technology, as the capital investment will be minimal for enhancing the efficiency of current rotary lime kilns. Retrofits would likely be attractive to lime manufacturers, as the purchase of a new lime kiln is on the order of a $30 million dollar investment, where as a MAT retrofit is estimated on the order of $1 million. The path for commercialization lies in partnering with existing lime kiln companies, who will be able to implement the microwave post heat sections in existing and new build kilns. A microwave equipment provider has been identified, who would make up part of the continued development and commercialization team.« less

Study on Al2O3 extraction from activated coal gangue under different calcination atmospheres

NASA Astrophysics Data System (ADS)

Dong, Ling; Liang, Xinxing; Song, Qiang; Gao, Gewu; Song, Lihua; Shu, Yuanfeng; Shu, Xinqian

2017-12-01

Coal gangue was calcinated under air, nitrogen, carbon dioxide, air-hydrogen, and hydrogen atmospheres. The effects of different calcination temperatures and atmospheres on the mineral composition of activated coal gangue were investigated by X-ray diffraction. Moreover, the acid leaching kinetics of aluminum oxide from coal gangue was investigated with sulfuric acid. It showed that the air atmosphere promoted kaolinite decomposition during coal gangue calcination. The hydrogen atmosphere promoted the activation and decomposition of kaolinite at reaction temperatures exceeding 650°C. The carbon dioxide atmosphere eliminated the influence of residual carbon on coal gangue. When the ratio of acid/coal gangue was 1.5 and reaction temperature was 650°C, the sulfuric acid leaching rate under air, air-hydrogen, carbon dioxide, hydrogen and nitrogen atmospheres were 93.66%, 90.90%, 84.06%, 81.91% and 77.54% respectively. The acid leaching reaction process conformed to unreacted shrinking core model of particle unchanged, and was controlled by the interfacial chemical reaction. The reaction kinetic equation for the leaching process was 1-(1-x)1/3=kt with an apparent activation energy of 48.97 kJ/mol.

Modification of waste coal gangue and its application in the removal of Mn(2+) from aqueous solution.

PubMed

Qiu, Ruifang; Cheng, Fangqin

We developed a new calcination method to convert coal gangue (CG), a common waste generated from coal production process, into a modified form, which could be used as an adsorbent to remove Mn(2+) from aqueous solution. Sodium tetraborate (Na2B4O7·10H2O) was added into the CG calcination process as an additive, and the concentrations of Na2B4O7·10H2O were optimized along with the calcination temperature to obtain the best adsorbent capacity of modified coal gangue (MCG). We applied multiple analytical methods such as scanning electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy and Brunauer-Emmett-Teller analysis to characterize the MCG. The results showed it had a smaller particle size and a larger specific surface area and pore volume after modification. It also indicated that the phase of CG transformed from kaolinite to metakaolinite after calcination. Moreover, a new substance was generated with two new peaks at 1,632 cm(-1) and 799 cm(-1). The Mn(2+) absorption capacity of MCG was evaluated using a series of experiments with different adsorbent doses, pH values and initial Mn(2+) concentrations during the adsorption process. We found that Mn(2+) adsorbent capacity of MCG increased by more than seven-fold compared to that of CG. The Langmuir isotherm model and the pseudo-second-order kinetic model provided the best fit to the adsorption processes.

Well-dispersed NiO nanoparticles supported on nitrogen-doped carbon nanotube for methanol electrocatalytic oxidation in alkaline media

NASA Astrophysics Data System (ADS)

Wang, Pengcheng; Zhou, Yingke; Hu, Min; Chen, Jian

2017-01-01

Nitrogen-doped carbon nanotube supporting NiO nanoparticles were synthesized by a chemical precipitation process coupled with subsequent calcination. The morphology and structure of the composites were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS), and the electrochemical performance was evaluated using cyclic voltammetry and chronoamperometric technique. The effects of nitrogen doping, calcination temperature and content of NiO nanoparticles on the electrocatalytic activity toward methanol oxidation were systematically studied. The results show that the uniformly dispersed ultrafine NiO nanoparticles supported on nitrogen-doped carbon nanotube are obtained after calcination at 400 °C. The optimized composite catalysts present high electrocatalytic activity, fast charge-transfer process, excellent accessibility and stability for methanol oxidation reaction, which are promising for application in the alkaline direct methanol fuel cells.

Study of Catalyst Variation Effect in Glycerol Conversion Process to Hydrogen Gas by Steam Reforming

NASA Astrophysics Data System (ADS)

Widayat; Hartono, R.; Elizabeth, E.; Annisa, A. N.

2018-04-01

Along with the economic development, needs of energy being increase too. Hydrogen as alternative energy has many usages. Besides that, hydrogen is one source of energy that is a clean fuel, but process production of hydrogen from natural gas as a raw material has been used for a long time. Therefore, there is need new invention to produce hydrogen from the others raw material. Glycerol, a byproduct of biodiesel production, is a compound which can be used as a raw material for hydrogen production. By using glycerol as a raw material of hydrogen production, we can get added value of glycerol as well as an energy source solution. The process production of hydrogen by steam reforming is a thermochemical process with efficiency 70%. This process needs contribution of catalyst to improve its efficiency and selectivity of the process. In this study will be examined the effect variation of catalyst for glycerol conversion process to hydrogen by steam reforming. The method for catalyst preparation was variation of catalyst impregnation composition, catalyst calcined with difference concentration of hydrochloric acid and calcined with difference hydrochloric acid ratio. After that, all of catalyst which have been prepared, used for steam reforming process for hydrogen production from glycerol as a raw material. From the study, the highest yield of hydrogen gas showed in the process production by natural zeolite catalyst with 1:15 Hydrochloric acid ratio was 42.28%. Hydrogen yield for 2M calcined natural zeolite catalyst was 38.37%, for ZSM-5 catalyst was 15.83%, for 0.5M calcined natural zeolite was 13.09% and for ultrasonic natural zeolite was 11.43%. The lowest yield of hydrogen gas showed in catalyst 2Zn/ZSM-5 with 11.22%. This result showed that hydrogen yield product was affected by catalyst variation because of the catalyst has difference characteristic and difference catalytic activity after the catalyst preparation process.

Screen-printed SnO2/CNT quasi-solid-state gel-electrolyte supercapacitor

NASA Astrophysics Data System (ADS)

Kuok, Fei-Hong; Liao, Chen-Yu; Chen, Chieh-Wen; Hao, Yu-Chuan; Yu, Ing-Song; Chen, Jian-Zhang

2017-11-01

This study investigates a quasi-solid-state gel-electrolyte supercapacitor fabricated with nanoporous SnO2/CNT nanocomposite electrodes and a polyvinyl alcohol/sulfuric acid (PVA/H2SO4) gel electrolyte. First, pastes containing SnO2 nanoparticles, CNTs, ethyl cellulose, and terpineol are screen-printed onto carbon cloth. A tube furnace is then used for calcining the SnO2/CNT electrodes on carbon cloth. After furnace-calcination, the wettability of SnO2/CNT significantly improved; furthermore, the XPS analysis shows that number of C-O bond and oxygen content significantly decrease after furnace-calcination owing to the burnout of the ethyl cellulose by the furnace calcination processes. The furnace-calcined SnO2/CNT electrodes sandwich the PVA/H2SO4 gel electrolyte to form a supercapacitor. The fabricated supercapacitor exhibits an areal capacitance of 5.61 mF cm-2 when flat and 5.68 mF cm-2 under bending with a bending radius (R) of 1.0 cm. After a 1000 cycle stability test, the capacitance retention rates of the supercapacitor are 96% and 97% when flat and under bending (R  =  1.0 cm), respectively.

Phosphorous removal from aqueous solution can be enhanced through the calcination of lime sludge.

PubMed

Bal Krishna, K C; Niaz, Mohamed R; Sarker, Dipok C; Jansen, Troy

2017-09-15

Water treatment plants generate an enormous amount of the sludge which is normally treated as waste. In the recent past, many investigations have been focused on developing an economical adsorbent using water treatment sludge to remove phosphorous (P) from aqueous solutions. However, the great extents of the studies have been limited in the use of alum- and iron-based sludges. This study, therefore, investigated the P removal performance of the calcined lime sludge. Calcined lime sludge at 700 °C significantly enhanced the P removal efficiency whereas marginal improvement was noted when the sludge calcined at 400 °C was tested. With increase P removal efficiency, final pH values of the solution also significantly increased. P removal efficiency of the calcined sludge decreased with increasing the initial P concentrations. However, the removal efficiency could be improved by increasing the weight of the sludge. Further analysis demonstrated that P removal trend followed both pseudo-second order and diffusion-chemisorption kinetics signifying the P removal is potentially due to a multi-mechanistic reaction in which, the process is controlled by intra-particle diffusion followed by chemisorptions. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effect of synthesis route on electrical and ethanol sensing characteristics for LaFeO3-δ nanoparticles by citric sol-gel method

NASA Astrophysics Data System (ADS)

Cao, Ensi; Yang, Yuqing; Cui, Tingting; Zhang, Yongjia; Hao, Wentao; Sun, Li; Peng, Hua; Deng, Xiao

2017-01-01

LaFeO3-δ nanoparticles were prepared by citric sol-gel method with different raw material choosing and calcination process. The choosing of polyethylene glycol instead of ethylene glycol as raw material and additional pre-calcination at 400 °C rather than direct calcination at 600 °C could result in the decrease of resistance due to the reduction of activation energy Ea. Meanwhile, the choosing of ethylene glycol as raw material and additional pre-calcination leads to the enhancement of sensitivity to ethanol. Comprehensive analysis on the sensitivity and XRD, SEM, TEM, XPS results indicates that the sensing performance of LaFeO3-δ should be mainly determined by the adsorbed oxygen species on Fe ions, with certain contribution from native active oxygen. The best sensitivity of 46.1-200 ppm ethanol at prime working temperature of 112 °C is obtained by the sample using ethylene glycol as raw material with additional pre-calcination, which originates from its uniformly-sized and well-dispersed particles as well as high atomic ratio of Fe/La at surface region.

Process parameters in the manufacture of ceramic ZnO nanofibers made by electrospinning

NASA Astrophysics Data System (ADS)

Nonato, Renato C.; Morales, Ana R.; Rocha, Mateus C.; Nista, Silvia V. G.; Mei, Lucia H. I.; Bonse, Baltus C.

2017-01-01

Zinc oxide (ZnO) nanofibers were prepared by electrospinning under different conditions using a solution of poly(vinyl alcohol) and zinc acetate as precursor. A 23 factorial design was made to study the influence of the process parameters in the electrospinning (collector distance, flow rate and voltage), and a 22 factorial design was made to study the influence of the calcination process (time and temperature). SEM images were made to analyze the fiber morphology before and after calcination process, and the images were made to measure the nanofiber diameter. X-ray diffraction was made to analyze the total precursor conversion to ZnO and the elimination of the polymeric carrier.

Stable mercury isotope ratios as tracers for Hg cycling at the inoperative New Idria Hg mine, California

NASA Astrophysics Data System (ADS)

Wiederhold, J. G.; Jew, A. D.; Brown, G. E.; Bourdon, B.; Kretzschmar, R.

2010-12-01

The seven stable isotopes of Hg are fractionated in the environment as a result of mass-dependent (MDF) and mass-independent (MIF) fractionation processes that can be studied in parallel by analyzing the ratios of even and odd mass Hg isotopes. MDF and MIF Hg isotope signatures of natural samples may provide a new tool to trace sources and transformations in environmental Hg cycling. However, the mechanisms controlling the extent of kinetic and equilibrium Hg isotope fractionations are still only partially understood. Thus, development of this promising tracer requires experimental calibration of relevant fractionation factors as well as assessment of natural variations of Hg isotope ratios under different environmental conditions. The inoperative Hg mine in New Idria (California, USA) represents an ideal case study to explore Hg isotope fractionation during Hg transformation and transport processes. More than a century of Hg mining and on-site thermal refining to obtain elemental Hg until 1972 produced large volumes of contaminated mine wastes which now represent sources of Hg pollution for the surrounding ecosystems. Here, we present Hg isotope data from various materials collected at New Idria using Cold-Vapor-MC-ICPMS with a long-term δ202Hg reproducibility of ±0.1‰ (2SD). Uncalcined mine waste samples were isotopically similar to NIST-3133 and did not exhibit any MIF signatures. In contrast, calcine samples, which represent the residue of the thermal ore processing at 700°C, had significantly heavier δ202Hg values of up to +1.5‰. In addition, we observed small negative MIF anomalies of the odd-mass Hg isotopes in the calcine samples, which could be caused either by nuclear volume fractionation or a magnetic isotope effect during or after the roasting process. The mass-dependent enrichment of heavy Hg isotopes in the calcine materials indicates that light Hg isotopes were preferentially removed during the roasting process, in agreement with a previous study by Stetson et al. (ES&T, 2009, 43:7331-7336). In order to further elucidate the Hg isotope signatures of the New Idria samples, we performed a three-step sequential extraction procedure to separate different Hg pools. The calcine samples exhibited a higher proportion of leachable Hg phases compared with the unrefined ore waste samples. The most soluble Hg pool (HAc/HCl, pH 2) had a significantly heavier MDF and more negative MIF signature than the bulk calcine samples, suggesting that the dissolution of more soluble Hg phases from calcine materials results in an enhanced flux of leached Hg which is isotopically distinct from the original ore. Moreover, this finding demonstrates that the Hg isotope fractionation during the ore roasting cannot be solely explained by a kinetic Rayleigh-type process which removes light Hg isotopes, but must additionally involve the formation of isotopically heavy secondary Hg phases in the calcine. The analysis of additional samples will enable us to test this hypothesis and to gain further insights into the applicability of stable Hg isotope ratios as source and process tracers in Hg-contaminated environments.

Nuclear proliferomics: A new field of study to identify signatures of nuclear materials as demonstrated on alpha-UO3.

PubMed

Schwerdt, Ian J; Brenkmann, Alexandria; Martinson, Sean; Albrecht, Brent D; Heffernan, Sean; Klosterman, Michael R; Kirkham, Trenton; Tasdizen, Tolga; McDonald Iv, Luther W

2018-08-15

The use of a limited set of signatures in nuclear forensics and nuclear safeguards may reduce the discriminating power for identifying unknown nuclear materials, or for verifying processing at existing facilities. Nuclear proliferomics is a proposed new field of study that advocates for the acquisition of large databases of nuclear material properties from a variety of analytical techniques. As demonstrated on a common uranium trioxide polymorph, α-UO 3 , in this paper, nuclear proliferomics increases the ability to improve confidence in identifying the processing history of nuclear materials. Specifically, α-UO 3 was investigated from the calcination of unwashed uranyl peroxide at 350, 400, 450, 500, and 550 °C in air. Scanning electron microscopy (SEM) images were acquired of the surface morphology, and distinct qualitative differences are presented between unwashed and washed uranyl peroxide, as well as the calcination products from the unwashed uranyl peroxide at the investigated temperatures. Differential scanning calorimetry (DSC), UV-Vis spectrophotometry, powder X-ray diffraction (p-XRD), and thermogravimetric analysis-mass spectrometry (TGA-MS) were used to understand the source of these morphological differences as a function of calcination temperature. Additionally, the SEM images were manually segmented using Morphological Analysis for MAterials (MAMA) software to identify quantifiable differences in morphology for three different surface features present on the unwashed uranyl peroxide calcination products. No single quantifiable signature was sufficient to discern all calcination temperatures with a high degree of confidence; therefore, advanced statistical analysis was performed to allow the combination of a number of quantitative signatures, with their associated uncertainties, to allow for complete discernment by calcination history. Furthermore, machine learning was applied to the acquired SEM images to demonstrate automated discernment with at least 89% accuracy. Copyright © 2018 Elsevier B.V. All rights reserved.

High speed production of YBCO precursor films by advanced TFA-MOD process

NASA Astrophysics Data System (ADS)

Ichikawa, H.; Nakaoka, K.; Miura, M.; Sutoh, Y.; Nakanishi, T.; Nakai, A.; Yoshizumi, M.; Izumi, T.; Shiohara, Y.

2009-10-01

YBa 2Cu 3O 7-y (YBCO) long tapes derived from the metal-organic deposition (MOD) method using the starting solution containing trifluoroacetate (TFA) have been developed with high critical currents ( I c) over 200 A/cm-width. However, high speed production of YBCO films is simultaneously necessary to satisfy the requirements of electric power device applications in terms of cost and the amounts of the tapes. In this work, we developed a new TFA-MOD starting solution using F-free salt of Y, TFA salt of Ba and Cu-Octylate for application to the coating/calcination process and discussed several issues by using the Multi-turn (MT) Reel-to-Reel (RTR) system calcination furnace for the purpose of high throughput without degradation of the properties. The coating system was improved for uniform deposition qualities in both longitudinal and transversal directions. YBCO films using the new starting solution at the traveling rate of 10 m/h in coating/calcination by the MT-RTR calcination furnace showed the values of the critical current density of 1.6 MA/cm 2 as thick as 1.5 μm at 77 K under the self fields after firing at the high heating rate in the crystallization.

Effect of calcination temperature on the microstructure and electronic properties of TiO2-ZnO nanocomposites and implications on photocatalytic activity

NASA Astrophysics Data System (ADS)

Menon, N. Gayathri; Tatiparti, Sankara Sarma V.; Mukherji, Suparna

2018-04-01

TiO2-ZnO nanocomposites with a constant Ti:Zn molar ratio of 1:0.1 were prepared via sol-gel process followed by calcination at 300, 400, 500, 600, and 700 °C. The structural and compositional characterizations of these nanocomposites were performed through XRD, FTIR, SEM, and EDAX. Bandgap was measured using DRS. Photocatalytic performance of the nanocomposites was evaluated by decolorization of methyl orange dye under UV and visible irradiation with and without aeration. The results showed that increase in calcination temperature resulted in nanocomposites with well-defined morphology. Although the particle size increased with increase in calcination temperature, the crystallinity of the particles also increased, resulting in enhanced photocatalytic activity. A temperature-dependent anatase-to-rutile phase transformation was observed in TiO2-ZnO nanocomposite beyond 600 °C. The calcination temperature influenced both dye adsorption on the nanocomposites and also dye decolorization by photocatalysis. Even when present at low molar concentration, ZnO in the nanocomposite caused sufficient decrease in bandgap (2.6 eV) at temperatures as low as 400 °C, such that visible irradiation could cause dye decolorization. However, the best decolorization performance was observed in the presence of the nanocomposite calcined at 600 °C. Aerated systems showed better performance in all cases. Desorption of the dye remaining adsorbed on the nanocomposite at the end of the photocatalytic reaction, confirmed that adsorption accounted for only 6.6 and 3% of dye removal in the nanocomposites calcined at 600 °C with UV and visible irradiation, respectively. However, in other systems, ignoring adsorption may cause significant overestimation in photocatalytic loss of dye from the system.

Photocatalytic Oxidation of Acetone Over High Thermally Stable TiO2 Nanosheets With Exposed (001) Facets.

PubMed

Shi, Ting; Duan, Youyu; Lv, Kangle; Hu, Zhao; Li, Qin; Li, Mei; Li, Xiaofang

2018-01-01

Anatase TiO 2 (A-TiO 2 ) usually exhibits superior photocatalytic activity than rutile TiO 2 (R-TiO 2 ). However, the phase transformation from A-TiO 2 to R-TiO 2 will inevitably happens when the calcination temperature is up to 600°C, which hampers the practical applications of TiO 2 photocatalysis in hyperthermal situations. In this paper, high energy faceted TiO 2 nanosheets (TiO 2 -NSs) with super thermal stability was prepared by calcination of TiOF 2 cubes. With increase in the calcination temperature from 300 to 600°C, TiOF 2 transforms into TiO 2 hollow nanoboxes (TiO 2 -HNBs) assembly from TiO 2 -NSs via Ostwald Rippening process. Almost all of the TiO 2 -HNBs are disassembled into discrete TiO 2 -NSs when calcination temperature is higher than 700°C. Phase transformation from A-TiO 2 to R-TiO 2 begins at 1000°C. Only when the calcination temperature is higher than 1200°C can all the TiO 2 -NSs transforms into R-TiO 2 . The 500°C-calcined sample (T500) exhibits the highest photoreactivity toward acetone oxidation possibly because of the production of high energy TiO 2 -NSs with exposed high energy (001) facets and the surface adsorbed fluorine. Surface oxygen vacancy, due to the heat-induced removal of surface adsorbed fluoride ions, is responsible for the high thermal stability of TiO 2 -NSs which are prepared by calcination of TiOF 2 cubes.

Calcine Waste Storage at the Idaho Nuclear Technology and Engineering Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

Staiger, Merle Daniel; M. C. Swenson

2005-01-01

This report documents an inventory of calcined waste produced at the Idaho Nuclear Technology and Engineering Center during the period from December 1963 to May 2000. The report was prepared based on calciner runs, operation of the calcined solids storage facilities, and miscellaneous operational information that establishes the range of chemical compositions of calcined waste stored at Idaho Nuclear Technology and Engineering Center. The report will be used to support obtaining permits for the calcined solids storage facilities, possible treatment of the calcined waste at the Idaho National Engineering and Environmental Laboratory, and to ship the waste to an off-sitemore » facility including a geologic repository. The information in this report was compiled from calciner operating data, waste solution analyses and volumes calcined, calciner operating schedules, calcine temperature monitoring records, and facility design of the calcined solids storage facilities. A compact disk copy of this report is provided to facilitate future data manipulations and analysis.« less

The effect of calcination on multi-walled carbon nanotubes produced by dc-arc discharge.

PubMed

Pillai, Sreejarani K; Augustyn, Willem G; Rossouw, Margaretha H; McCrindle, Robert I

2008-07-01

Multi-walled carbon nanotubes were synthesized by dc-arc discharge in helium atmosphere and the effect of calcination at different temperatures ranging from 300-600 degrees C was studied in detail. The degree of degradation to the structural integrity of the multi-walled carbon nanotubes during the thermal process was studied by Raman spectroscopy, Scanning electron microscopy and High resolution transmission electron microscopy. The thermal behaviour of the as prepared and calcined samples was investigated by thermogravimetric analysis. Calcination in air at 400 degrees C for 2 hours was found to be an efficient and simple method to eliminate carbonaceous impurities from the nanotube bundles with minimal damage to the tube walls and length. The impurities were oxidized at a faster rate when compared to the nanotubes and gave good yield of about 50%. The nanotubes were observed to be damaged at temperature higher than 450 degrees C. The results show that this method is less destructive when compared liquid phase oxidation with 5 M HNO3.

Direct cementitious waste option study report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dafoe, R.E.; Losinski, S.J.

A settlement agreement between the Department of Energy (DOE) and the State of Idaho mandates that all high-level radioactive waste (HLW) now stored at the Idaho Chemical Processing Plant (ICPP) will be treated so that it is ready to be moved out of Idaho for disposal by a target data of 2035. This study investigates the direct grouting of all ICPP calcine (including the HLW dry calcine and those resulting from calcining sodium-bearing liquid waste currently residing in the ICPP storage tanks) as the treatment method to comply with the settlement agreement. This method involves grouting the calcined waste andmore » casting the resulting hydroceramic grout into stainless steel canisters. These canisters will be stored at the Idaho National Engineering and Environmental Laboratory (INEEL) until they are sent to a national geologic repository. The operating period for grouting treatment will be from 2013 through 2032, and all the HLW will be treated and in interim storage by the end of 2032.« less

Phase analysis of ZrO2-SiO2 systems synthesized through Ball milling mechanical activations

NASA Astrophysics Data System (ADS)

Nurlaila, Rizka; Musyarofah, Muwwaqor, Nibras Fuadi; Triwikantoro, Kuswoyo, Anton; Pratapa, Suminar

2017-01-01

Zircon powders have been produced from raw materials of amorphous zirconia and amorphous silica powders obtained from natural zircon sand of Kalimantan Tengah, Indonesia. Synthesis process was started with the extraction of zircon powder to produce sodium silicate solution and pure zircon powder. The amorphous zirconia and silica powders were prepared by alkali fusion and co-precipitation techniques. The powders were mixed using a planetary ball mill, followed by a calcination of various holding time of 3, 10, and 15 h. Phase characterization was done using X-Ray Diffraction (XRD) technique and analysis of the diffraction data was carried out using Rietica and MAUD software. The identified phases after the calcination were zircon, tetragonal zirconia, and cristobalite. The highest zircon content was obtained in the sample calcinated for15 hours - reaching 99.66 %wt. Crystallite size analysis revealed that the samples calcinated for 3, 10, and 15 h exhibited zircon crystal size of 176 (1) nm, 191 (1) nm and 233 (1) nm respectively.

LAB-SCALE DEMONSTRATION OF PLUTONIUM PURIFICATION BY ANION EXCHANGE, PLUTONIUM (IV) OXALATE PRECIPITATION, AND CALCINATION TO PLUTONIUM OXIDE TO SUPPORT THE MOX FEED MISSION

DOE Office of Scientific and Technical Information (OSTI.GOV)

Crowder, M.; Pierce, R.

2012-08-22

H-Canyon and HB-Line are tasked with the production of PuO{sub 2} from a feed of plutonium metal. The PuO{sub 2} will provide feed material for the MOX Fuel Fabrication Facility. After dissolution of the Pu metal in H-Canyon, the solution will be transferred to HB-Line for purification by anion exchange. Subsequent unit operations include Pu(IV) oxalate precipitation, filtration and calcination to form PuO{sub 2}. This report details the results from SRNL anion exchange, precipitation, filtration, calcination, and characterization tests, as requested by HB-Line1 and described in the task plan. This study involved an 80-g batch of Pu and employed testmore » conditions prototypical of HB-Line conditions, wherever feasible. In addition, this study integrated lessons learned from earlier anion exchange and precipitation and calcination studies. H-Area Engineering selected direct strike Pu(IV) oxalate precipitation to produce a more dense PuO{sub 2} product than expected from Pu(III) oxalate precipitation. One benefit of the Pu(IV) approach is that it eliminates the need for reduction by ascorbic acid. The proposed HB-Line precipitation process involves a digestion time of 5 minutes after the time (44 min) required for oxalic acid addition. These were the conditions during HB-line production of neptunium oxide (NpO{sub 2}). In addition, a series of small Pu(IV) oxalate precipitation tests with different digestion times were conducted to better understand the effect of digestion time on particle size, filtration efficiency and other factors. To test the recommended process conditions, researchers performed two nearly-identical larger-scale precipitation and calcination tests. The calcined batches of PuO{sub 2} were characterized for density, specific surface area (SSA), particle size, moisture content, and impurities. Because the 3013 Standard requires that the calcination (or stabilization) process eliminate organics, characterization of PuO{sub 2} batches monitored the presence of oxalate by thermogravimetric analysis-mass spectrometry (TGA-MS). To use the TGA-MS for carbon or oxalate content, some method development will be required. However, the TGA-MS is already used for moisture measurements. Therefore, SRNL initiated method development for the TGA-MS to allow quantification of oxalate or total carbon. That work continues at this time and is not yet ready for use in this study. However, the collected test data can be reviewed later as those analysis tools are available.« less

Characterization and morphology of prepared titanium dioxide nanofibers by electrospinning.

PubMed

Park, Ju-Young; Lee, In-Hwa

2010-05-01

Dispersed titanium dioxide in polymer nanofibers were prepared by sol-gel processing and electrospinning techniques using titanium isopropoxide (TiP)/polyvinylpyrrolidone (PVP) solution. The prepared titanium dioxide nanofibers were characterized by FE-SEM, TEM, XRD, and FT-IR. Pure titanium dioxide nanofibers were obtained from calcination of inorganic-organic composite fiber. The diameter of titanium oxide nanofibers were in the range of 70 nm to 150 nm. Prepared titanium dioxide nanofibers show rough surface and rather small diameter compare with TiP/PVP composite nanofibers. After calcined at 500 degrees C, TiO2 nanofibers convert into anatase and rutile mixed phased from amorphous structure. Calcination of these composite fibers above 600 degrees C resulted in pure rutile TiO2 nanofibers.

Synthesis of CaCu3Ti4O12 by modified Sol-gel method with Hydrothermal process

NASA Astrophysics Data System (ADS)

Masingboon, C.; Rungruang, S.

2017-09-01

CaCu3Ti4O12 powders were synthesized by modified Sol-gel method with Hydrothermal process using Ca(NO3)2· 4H2O, Cu(NO3)2·3H2O, Ti(OC3H7)4 and freshly extracted egg white (ovalbumin) in aqueous medium. The precursor was calcined at 800, 900 and 1000 °C in air for 8 h to obtain nanocrystalline powders of CaCu3Ti4O12. The calcined CaCu3Ti4O12 powders were characterized by XRD, TEM and EDX. The XRD results indicated that all calcined samples have a typical perovskite CaCu3Ti4O12 structure and a small amount of CaTiO3, CuO and TiO2. TEM micrographs showed particle size 100 - 500 nm and EDX results showed elements of CaCu3Ti4O12 powders have calcium, copper, titanium and oxygen.

Aqueous Chloride Operations Overview: Plutonium and Americium Purification/Recovery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gardner, Kyle Shelton; Kimball, David Bryan; Skidmore, Bradley Evan

These are a set of slides intended for an information session as part of recruiting activities at Brigham Young University. It gives an overview of aqueous chloride operations, specifically on plutonium and americium purification/recovery. This presentation details the steps taken perform these processes, from plutonium size reduction, dissolution, solvent extraction, oxalate precipitation, to calcination. For americium recovery, it details the CLEAR (chloride extraction and actinide recovery) Line, oxalate precipitation and calcination.

Sorption-desorption of antimony species onto calcined hydrotalcite: Surface structure and control of competitive anions.

PubMed

Constantino, Leonel Vinicius; Quirino, Juliana Nunes; Abrão, Taufik; Parreira, Paulo Sérgio; Urbano, Alexandre; Santos, Maria Josefa

2018-02-15

Calcined hydrotalcite can be applied to remove anionic contaminants from aqueous systems such as antimony species due to its great anion exchange capacity and high surface area. Hence, this study evaluated antimonite and antimonate sorption-desorption processes onto calcined hydrotalcite in the presence of nitrate, sulfate and phosphate. Sorption and desorption experiments of antimonite and antimonate were carried out in batch equilibrium and the post-sorption solids were analyzed by X-ray fluorescence (EDXRF). Sorption data were better fitted by dual-mode Langmuir-Freundlich model (R 2 >0.99) and desorption data by Langmuir model. High maximum sorption capacities were found for the calcined hydrotalcite, ranging from 617 to 790meqkg -1 . The competing anions strongly affected the antimony sorption. EDXRF analysis and mathematical modelling showed that sulfate and phosphate presented higher effect on antimonite and antimonate sorption, respectively. High values for sorption efficiency (SE=99%) and sorption capacity were attributed to the sorbent small particles and the large surface area. Positive hysteresis indexes and low mobilization factors (MF>3%) suggest very low desorption capacity to antimony species from LDH. These calcined hydrotalcite characteristics are desirable for sorption of antimony species from aqueous solutions. Copyright © 2017. Published by Elsevier B.V.

Adsorptive removal of arsenic by novel iron/olivine composite: Insights into preparation and adsorption process by response surface methodology and artificial neural network.

PubMed

Ghosal, Partha S; Kattil, Krishna V; Yadav, Manoj K; Gupta, Ashok K

2018-03-01

Olivine, a low-cost natural material, impregnated with iron is introduced in the adsorptive removal of arsenic. A wet impregnation method and subsequent calcination were employed for the preparation of iron/olivine composite. The major preparation process parameter, viz., iron loading and calcination temperature were optimized through the response surface methodology coupled with a factorial design. A significant variation of adsorption capacity of arsenic (measured as total arsenic), i.e., 63.15 to 310.85 mg/kg for arsenite [As(III) T ] and 76.46 to 329.72 mg/kg for arsenate [As(V) T ] was observed, which exhibited the significant effect of the preparation process parameters on the adsorption potential. The iron loading delineated the optima at central points, whereas a monotonous decreasing trend of adsorption capacity for both the As(III) T and As(V) T was observed with the increasing calcination temperature. The variation of adsorption capacity with the increased iron loading is more at lower calcination temperature showing the interactive effect between the factors. The adsorbent prepared at the optimized condition of iron loading and calcination temperature, i.e., 10% and 200 °C, effectively removed the As(III) T and As(V) T by more than 96 and 99%, respectively. The material characterization of the adsorbent showed the formation of the iron compound in the olivine and increase in specific surface area to the tune of 10 multifold compared to the base material, which is conducive to the enhancement of the adsorption capacity. An artificial neural network was applied for the multivariate optimization of the adsorption process from the experimental data of the univariate optimization study and the optimized model showed low values of error functions and high R 2 values of more than 0.99 for As(III) T and As(V) T . The adsorption isotherm and kinetics followed Langmuir model and pseudo second order model, respectively demonstrating the chemisorption in this study. Copyright © 2017 Elsevier Ltd. All rights reserved.

Treatment of a non-azo dye aqueous solution by CWAO in continuous reactor using a Ni catalyst derived from hydrotalcite-like precursor.

PubMed

Vallet, Ana; Besson, Michèle; Ovejero, Gabriel; García, Juan

2012-08-15

Catalytic wet air oxidation (CWAO) of a Basic Yellow 11 (BY11) aqueous solution, chosen as a model of a hardly biodegradable non-azo dye was carried out in a continuous-flow trickle-bed reactor, using nickel supported over hydrotalcite precursor calcined at 550°C. An increase in the reaction temperature (120-180°C), and a decrease in dye concentration (1000-3000 ppm) or liquid flow rate (0.1-0.7 mL min(-1)) enhanced the CWAO performance in a 30 and 19% for the variation of the temperature and concentration respectively. After a small leaching observed within the first hours, the catalyst proved to be very stable during the 65-day reaction. The CWAO process was found to be very efficient, achieving BY11 conversion up to 95% and TOC conversion up to 85% at 0.1 mL min(-1) and 180°C under 5 MPa air. Copyright © 2012 Elsevier B.V. All rights reserved.

A new in vivo screening model for posterior spinal bone formation: comparison of ten calcium phosphate ceramic material treatments.

PubMed

Wilson, Clayton E; Kruyt, Moyo C; de Bruijn, Joost D; van Blitterswijk, Clemens A; Oner, F Cumhur; Verbout, Abraham J; Dhert, Wouter J A

2006-01-01

This study presents a new screening model for evaluating the influence of multiple conditions on the initial process of bone formation in the posterior lumbar spine of a large animal. This model uses cages designed for placement on the decorticated transverse process of the goat lumbar spine. Five conduction channels per cage, each be defined by a different material treatment, are open to both the underlying bone and overlying soft tissue. The model was validated in ten adult Dutch milk goats, with each animal implanted with two cages containing a total of ten calcium phosphate material treatments according to a randomized complete block design. The ten calcium phosphate ceramic materials were created through a combination of material chemistry (BCP, TCP, HA), sintering temperature (low, medium, high), calcination and surface roughness treatments. To monitor the bone formation over time, fluorochrome markers were administered at 3, 5 and 7 weeks and the animals were sacrificed at 9 weeks after implantation. Bone formation in the conduction channels was investigated by histology and histomorphometry of non-decalcified sections using traditional light and epifluorescent microscopy. According to both observed and measured bone formation parameters, materials were ranked in order of increasing magnitude as follows: low sintering temperature BCP (rough and smooth) approximately medium sintering temperature BCP approximately = TCP > calcined low sintering temperature HA > non-calcined low sintering temperature HA > high sintering temperature BCP (rough and smooth) > high sintering temperature HA (calcined and non-calcined). These results agree closely with those obtained in previous studies of osteoconduction and bioactivity of ceramics thereby validating the screening model presented in this study.

Evaluation of the Magnesium Hydroxide Treatment Process for Stabilizing PFP Plutonium/Nitric Acid Solutions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gerber, Mark A.; Schmidt, Andrew J.; Delegard, Calvin H.

2000-09-28

This document summarizes an evaluation of the magnesium hydroxide [Mg(OH)2] process to be used at the Hanford Plutonium Finishing Plant (PFP) for stabilizing plutonium/nitric acid solutions to meet the goal of stabilizing the plutonium in an oxide form suitable for storage under DOE-STD-3013-99. During the treatment process, nitric acid solutions bearing plutonium nitrate are neutralized with Mg(OH)2 in an air sparge reactor. The resulting slurry, containing plutonium hydroxide, is filtered and calcined. The process evaluation included a literature review and extensive laboratory- and bench-scale testing. The testing was conducted using cerium as a surrogate for plutonium to identify and quantifymore » the effects of key processing variables on processing time (primarily neutralization and filtration time) and calcined product properties.« less

PCDD/PCDF reduction by the co-combustion process.

PubMed

Lee, Vinci K C; Cheung, Wai-Hung; McKay, Gordon

2008-01-01

A novel process, termed the co-combustion process, has been developed and designed to utilise the thermal treatment of municipal solid waste (MSW) in cement clinker production and reduce PCDD/PCDF emissions. To test the conceptual design; detailed engineering design of the process and equipment was performed and a pilot plant was constructed to treat up to 40 tonnes MSW per day. The novel process features included several units external to the main traditional cement rotary kiln: an external calcinations unit in which the hot gas calcined the limestone thus making significant energy savings for this chemical reaction; the lime generated was used in a second chamber to act as a giant acid gas scrubber to remove SOx and particularly HCl (a source of chloride); an external rotary kiln and secondary combustion unit capable of producing a hot gas at 1200 degrees C; a gas cooler to simulate a boiler turbogenerator set for electricity generation; the incorporation of some of the bottom ash, calcined lime and dust collector solids into the cement clinker. A PCDD/PCDF inventory has been completed for the entire process and measured PCDD/PCDF emissions were 0.001 ng I-TEQ/Nm(3) on average which is 1% of the best practical means [Hong Kong Environmental Protection Department, 2001. A guidance note on the best practicable means for incinerators (municipal waste incineration), BPM12/1] MSW incineration emission limit values.

40 CFR 98.86 - Data reporting requirements.

Code of Federal Regulations, 2012 CFR

2012-07-01

...) Monthly fraction of total CaO, total MgO, non-calcined CaO and non-calcined MgO in clinker for each kiln (as wt-fractions). (7) Method used to determine non-calcined CaO and non-calcined MgO in clinker. (8) Quarterly fraction of total CaO, total MgO, non-calcined CaO and non-calcined MgO in CKD not recycled to the...

Isotopic Variability of Mercury in Ore, Mine-Waste Calcine, and Leachates of Mine-Waste Calcine from Areas Mined for Mercury

PubMed Central

2009-01-01

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that δ202Hg values relative to NIST 3133 of calcine (up to 1.52‰) in the Terlingua district, Texas, are as much as 3.24‰ heavier than cinnabar (−1.72‰) prior to retorting. In addition, δ202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17‰ heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, δ202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff. PMID:19848142

Isotopic variability of mercury in ore, mine-waste calcine, and leachates of mine-waste calcine from areas mined for mercury

USGS Publications Warehouse

Stetson, S.J.; Gray, J.E.; Wanty, R.B.; Macalady, D.L.

2009-01-01

The isotopic composition of mercury (Hg) was determined in cinnabar ore, mine-waste calcine (retorted ore), and leachates obtained from water leaching experiments of calcine from two large Hg mining districts in the U.S. This study is the first to report significant mass-dependent Hg isotopic fractionation between cinnabar ore and resultant calcine. Data indicate that ??202Hg values relative to NIST 3133 of calcine (up to 1.52???) in the Terlingua district, Texas, are as much as 3.24??? heavier than cinnabar (-1.72???) prior to retorting. In addition, ??202Hg values obtained from leachates of Terlingua district calcines are isotopically similar to, or as much as 1.17??? heavier than associated calcines, most likely due to leaching of soluble, byproduct Hg compounds formed during ore retorting that are a minor component in the calcines. As a result of the large fractionation found between cinnabar and calcine, and because calcine is the dominant source of Hg contamination from the mines studied, ??202Hg values of calcine may be more environmentally important in these mined areas than the primary cinnabar ore. Measurement of the Hg isotopic composition of calcine is necessary when using Hg isotopes for tracing Hg sources from areas mined for Hg, especially mine water runoff. ?? 2009 American Chemical Society.

Fabrication of nano structural biphasic materials from phosphogypsum waste and their in vitro applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mohamed, Khaled R., E-mail: Kh_rezk966@yahoo.com; Mousa, Sahar M.; Inorganic Chemistry Department, National Research Centre, Dokki, P.O. Box 12622, 11787 Cairo

2014-02-01

Graphical abstract: (a) Schema of the process, (b) TEM of nano particles of biphasic materials and (c) SEM of post-immersion. - Highlights: • Ratio of HA and β-TCP phases were controlled by thermal treatment. • HA partially decomposed into β-TCP with other bioactive phases. • Calcined HA at 900 °C is the best for the bioactivity behavior. - Abstract: In this study, a novel process of preparing biphasic calcium phosphate (BCP) is proposed. Also its bioactivity for the utilization of the prepared BCP as a biomaterial is studied. A mixture of calcium hydroxyapatite (HAP) and tricalcium phosphate (β-TCP) could bemore » obtained by thermal treatment of HAP which was previously prepared from phosphogypsum (PG) waste. The chemical and phase composition, morphology and particle size of prepared samples was characterized by X-ray diffraction (XRD), Infrared spectroscopy (IR), Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The bioactivity was investigated by soaking of the calcined samples in simulated body fluid (SBF). Results confirmed that the calcination temperatures played an important role in the formation of calcium phosphate (CP) materials. XRD results indicated that HAP was partially decomposed into β-TCP. The in vitro data confirmed that the calcined HAP forming BCP besides other phases such as pyrophosphate and silica are bioactive materials. Therefore, BCP will be used as good biomaterials for medical applications.« less

Effect of ph Value and Calcination Temperature on Structure and Magnetic Properties of Strontium Hexaferrite Thin Film

NASA Astrophysics Data System (ADS)

Shanaghi, A.

2012-02-01

Strontium hexaferrite was widely used in the fabrication of commercial permanent magnets and certain microwave devices. In this study, the strontium hexaferrite nanoparticle coatings were prepared by sol-gel method and using spin coating process on silicon substrate, then the effect of pH value, such as 5, 7 and 9, and calcination temperatures, such as 600°C, 800°C, and 1000°C, on structural and magnetic properties of strontium hexaferrite thin films were investigated by XRD, SEM and VSM measurements. The maximum saturation magnetization value of 57.43 emu/g and coercivity value of 3908 Oe were achieved for the thin film with crystallite size approximately 41 nm, prepared at pH value of 7 and calcinations temperature of 800°C.

Biodiesel production from waste frying oil using waste animal bone and solar heat.

PubMed

Corro, Grisel; Sánchez, Nallely; Pal, Umapada; Bañuelos, Fortino

2016-01-01

A two-step catalytic process for the production of biodiesel from waste frying oil (WFO) at low cost, utilizing waste animal-bone as catalyst and solar radiation as heat source is reported in this work. In the first step, the free fatty acids (FFA) in WFO were esterified with methanol by a catalytic process using calcined waste animal-bone as catalyst, which remains active even after 10 esterification runs. The trans-esterification step was catalyzed by NaOH through thermal activation process. Produced biodiesel fulfills all the international requirements for its utilization as a fuel. A probable reaction mechanism for the esterification process is proposed considering the presence of hydroxyapatite at the surface of calcined animal bones. Copyright © 2015 Elsevier Ltd. All rights reserved.

Process for vitrification of contaminated sodium oxide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Blair, H.T.; Mellinger, G.B.

1983-03-01

A glass composition was developed to accommodate 30 wt % sodium oxide and resist devitrification and leaching. An in-can melting process that is compatible with a comtaminated sodium calciner developed by Argonne National Laboratory was tested both on a laboratory and on an engineering scale and found to be viable. The Liquid Metal Fast Breeder Reactor experimental program continues to produce elemental sodium contaminated with radionuclides. This material is presently in temporary storage facilities because the current criterion will not permit alkali metals to be disposed of in shallow land burials. As a first step in treatment, Argonne National Laboratorymore » (ANL) has developed a calciner that will convert the sodium metal to an oxide. In work supported by the U.S. Department of Energy, Pacific Northwest Laboratory (PNL) is developing and demonstrating a process that is compatible with the calciner and facilities at ANL-West for incorporating sodium oxide into a glass. Glass, which normally contains sodium oxide, was chosen as the waste form because it is chemically durable and nondispersible. It is simple to produce, and the technology for incorporating nuclear wastes into glass is well developed.« less

Balancing Sodium Impurities in Alumina for Improved Properties

NASA Astrophysics Data System (ADS)

Wijayaratne, Hasini; Hyland, Margaret; McIntosh, Grant; Perander, Linus; Metson, James

2018-06-01

As there are direct and indirect impacts of feed material purity on the aluminum production process and metal grade, there is a high demand on the so-called pure smelter grade alumina (SGA)—the main feedstock for aluminum production. In this work, impurities within the precursor gibbsite used for SGA production and SGA are studied using NanoSIMS and XPS with a focus on sodium—the most abundant impurity. Although the industry trend is towards minimizing sodium due to the well-known negative impacts on the process, high sodium is also correlated with relatively attrition-resistant calcined products. Here, we show that this relationship is indirect and arises from sodium's role in inhibiting α-alumina formation. Alpha alumina formation in SGA has previously been demonstrated to induce a macro-porous and therefore attrition-prone microstructure. Sodium distribution within the precursor gibbsite and its migration during the calcination process are proposed to be most likely responsible for the spatial distribution of α-alumina within the calcined product grain. This in turn determines the behavior of the product during its transportation and handling (i.e., attrition). Therefore, tolerance of a certain amount of sodium within the precursor material does demonstrate a net benefit while balancing its negative impacts on the process.

Effects on structural, optical, and magnetic properties of pure and Sr-substituted MgFe2O4 nanoparticles at different calcination temperatures

NASA Astrophysics Data System (ADS)

Loganathan, A.; Kumar, K.

2016-06-01

In the present work, pure and Sr2+ ions substituted Mg ferrite nanoparticles (NPs) had been prepared by co-precipitation method and their structural, optical, and magnetic properties at different calcination temperatures were studied. On this purpose, thermo gravimetric and differential thermal analysis (TG-DTA), Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), scanning electron microscopy, UV-Visible diffused reflectance spectroscopy, impedance spectroscopy, and vibrating sample magnetometer were carried out. The exo- and endothermic processes of synthesized precursors were investigated by TG-DTA measurements. The structural properties of the obtained products were examined by XRD analysis and show that the synthesized NPs are in the cubic spinel structure. The existence of two bands around 578-583 and 430-436 cm-1 in FT-IR spectrum also confirmed the formation of spinel-structured ferrite NPs. The lattice constants and particle size are estimated using XRD data and found to be strongly dependent on calcination temperatures. The optical, electrical, and magnetic properties of ferrite compositions also investigated and found to be strongly dependant on calcination temperatures.

CRADA opportunities in removal of particulates from hot-gas streams by filtration

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, D H

1995-06-01

Our analyses of samples and operating data from the Pressurized Fluidized Bed Combustion (PFBC), cyclone, and filtration units of the Tidd Clean Coal demonstration facility show that calcined dolomitic sorbent reacted with SO{sub 2} (and O{sub 2}) to form Sulfates (CaSO{sub 4} and CaMgn [SO{sub 4}]n+1) not only in the PFBC bed, but also in the filtration vessel. Analyses of limited data from the journal literature suggest that the filter-vessel reactions may have produced sulfate {open_quotes}necks,{close_quotes} which bonded the particles together, thus substantially increasing the critical angle of repose and shear tensile strengths of the filtered powders. This proposed mechanismmore » rationalizes the {open_quotes}bridging{close_quotes} and other particle-accumulation problems that caused filter breakage. Engineering services potentially available to resolve these problems include elucidation and modeling of ex-situ and in-situ filter-vessel chemistry, measurement and modeling of particulate materials properties, and measurement and modeling of cleaning back-pulse aerodynamics and cleaning efficiencies.« less

On a clean power generation system with the co-gasification of biomass and coal in a quadruple fluidized bed gasifier.

PubMed

Yan, Linbo; He, Boshu

2017-07-01

A clean power generation system was built based on the steam co-gasification of biomass and coal in a quadruple fluidized bed gasifier. The chemical looping with oxygen uncoupling technology was used to supply oxygen for the calciner. The solid oxide fuel cell and the steam turbine were combined to generate power. The calcium looping and mineral carbonation were used for CO 2 capture and sequestration. The aim of this work was to study the characteristics of this system. The effects of key operation parameters on the system total energy efficiency (ŋ ten ), total exergy efficiency (ŋ tex ) and carbon sequestration rate (R cs ) were detected. The energy and exergy balance calculations were implemented and the corresponding Sankey and Grassmann diagrams were drawn. It was found that the maximum energy and exergy losses occurred in the steam turbine. The system ŋ ten and ŋ tex could be ∼50% and ∼47%, and R cs could be over unit. Copyright © 2017 Elsevier Ltd. All rights reserved.

Influence of periodically changing oxidizing and reducing environment on sulfur capture under PFBC conditions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Yrjas, P.; Hupa, M.

1997-12-31

In the literature it has been reported that sulfur capture with limestone (CaCO{sub 3}) under atmospheric fluidized bed combustion conditions reaches a maximum at about 850 C. Previously, the maximum has been attributed to the sintering of the sorbent particles which decreases the reactive surface area. Lately, also another explanation has been reported. In this case the sulfur capture decrease at higher temperatures was concluded to be due to fluctuating oxidizing/reducing conditions in the atmospheric combustor. In this paper the influence of alternating oxidizing/reducing conditions on SO{sub 2} capture at atmospheric and elevated pressure (15 bar) is reported. In themore » pressurized case, the CO{sub 2} partial pressure was kept high enough to prevent CaCO{sub 3} from calcining and therefore the CaSO{sub 4} would not form CaO but CaCO{sub 3} from calcining and therefore the CaSO{sub 4} would not form CaO but CaCO{sub 3} under reducing conditions. The experiments were done with a pressurized TGA by periodically changing the gas environment between oxidizing (O{sub 2}, SO{sub 2}, CO{sub 2} and N{sub 2}) and slightly reducing (CO, SO{sub 2}, CO{sub 2} and N{sub 2}) gas mixtures at different temperatures. The results showed that under normal pressure and slightly reducing conditions CaO formation from CaSO{sub 4} increased with temperature as expected. However, no significant amounts of CaCO{sub 3} were formed from CaSO{sub 4} at elevated pressure. It was also concluded that since the formation of CaO from CaSO{sub 4} was relatively slow it could not explain the sharp sulfur capture maximum at about 850 C. Therefore, it was assumed that the strongly reducing zones, where CaS thermodynamically is the stable compound, may play a more important role than the slightly reducing zones, concerning the sulfur capture in fluidized bed combustors.« less

Thermostable photocatalytically active TiO2 anatase nanoparticles

NASA Astrophysics Data System (ADS)

Qi, Fei; Moiseev, Anna; Deubener, Joachim; Weber, Alfred

2011-03-01

Anatase is the low-temperature (300-550 °C) crystalline polymorph of TiO2 and it transforms to rutile upon heating. For applications utilizing the photocatalytic properties of nanoscale anatase at elevated temperatures (over 600 °C) the issue of phase stabilisation is of major interest. In this study, binary TiO2/SiO2 particles were synthesized by a flame aerosol process with TiCl4 and SiCl4 as precursors. The theoretical Si/Ti ratio was varied in the range of 0.7-1.3 mol/mol. The synthesized TiO2/SiO2 samples were heat treated at 900 and 1,000 °C for 3 h to determine the thermostability of anatase. Pyrogenic TiO2 P25 (from Evonik/Degussa, Germany) widely applied as photocatalyst was used as non-thermostabilized reference material for comparison of photocatalytic activity of powders. Both the non-calcinated and calcinated powders were characterized by means of XRD, TEM and BET. Photocatalytic activity was examined with dichloroacetic acid (DCA) chosen as a model compound. It was found that SiO2 stabilized the material retarding the collapse of catalyst surface area during calcination. The weighted anatase content of 85% remains completely unchanged even after calcination at 1,000 °C. The presence of SiO2 layer/bridge as spacer between TiO2 particles freezes the grain growth: the average crystallite size increased negligibly from 17 to 18 nm even during the calcination at 1,000 °C. Due to the stabilizing effect of SiO2 the titania nanoparticles calcinated at 900 and 1,000 °C show significant photocatalytic activity. Furthermore, the increase in photocatalytic activity with calcination temperature indicates that the titania surface becomes more accessible either due to intensified cracking of the SiO2 layer or due to enhanced transport of SiO2 into the necks thus releasing additional titania surface.

UV-vis-DR study of VO x/SiO 2 catalysts prepared by sol-gel method

NASA Astrophysics Data System (ADS)

Moussa, N.; Ghorbel, A.

2008-12-01

Vanadia-silica catalysts with different vanadium loadings were prepared by sol-gel process. UV-vis diffuse-reflectance spectroscopy was used to elucidate the effect of drying mode (i.e., xerogel vs. aerogel), vanadium loading and calcination on the molecular structure of supported vanadium species. The results indicate that for vanadium loading ranging from 2.8 to 11.2 wt.%, the band-gap energies of all catalysts varying from 2.28 to 2.68 eV which demonstrate that vanadium oxides are predominantly in octahedral structure with the presence of tetrahedral species. The discrimination of different surface VO x species has been based on their characteristic Ligand to Metal Charge Transfer (LMCT) O → V(V) and d-d transition. It was found that the LMCT band position of V dbnd O bond is not affected by calcination either in xerogels or in aerogels but the position and the shape of bands relative to bridging V sbnd O sbnd V bonds are affected by vanadium loading, calcination and drying mode. For the same V/Si ratio, band-gap energy of xerogel is lower than that of aerogel which indicate that vanadium species are more dispersed in aerogels than in xerogels. Drying and calcination led to rearrangement, dehydration, cleavage and crystallization of vanadium species which explain the presence of some amount of crystalline V 2O 5 in calcined samples.

Preparation of TiO₂ nanocrystallite powders coated with 9 mol% ZnO for cosmetic applications in sunscreens.

PubMed

Ko, Horng-Huey; Chen, Hui-Ting; Yen, Feng-Ling; Lu, Wan-Chen; Kuo, Chih-Wei; Wang, Moo-Chin

2012-01-01

The preparation of TiO(2) nanocrystallite powders coated with and without 9 mol% ZnO has been studied for cosmetic applications in sunscreens by a co-precipitation process using TiCl(4) and Zn(NO(3))(2)·6H(2)O as starting materials. XRD results show that the phases of anatase TiO(2) and rutile TiO(2) coexist for precursor powders without added ZnO (T-0Z) and calcined at 523 to 973 K for 2 h. When the T-0Z precursor powders are calcined at 1273 K for 2 h, only the rutile TiO(2) appears. In addition, when the TiO(2) precursor powders contain 9 mol% ZnO (T-9Z) are calcined at 873 to 973 K for 2 h, the crystallized samples are composed of the major phase of rutile TiO(2) and the minor phases of anatase TiO(2) and Zn(2)Ti(3)O(8). The analyses of UV/VIS/NIR spectra reveal that the absorption of the T-9Z precursor powders after being calcined has a red-shift effect in the UV range with increasing calcination temperature. Therefore, the TiO(2) nanocrystallite powders coated with 9 mol% ZnO can be used as the attenuate agent in the UV-A region for cosmetic applications in sunscreens.

Preparation of TiO2 Nanocrystallite Powders Coated with 9 mol% ZnO for Cosmetic Applications in Sunscreens

PubMed Central

Ko, Horng-Huey; Chen, Hui-Ting; Yen, Feng-Ling; Lu, Wan-Chen; Kuo, Chih-Wei; Wang, Moo-Chin

2012-01-01

The preparation of TiO2 nanocrystallite powders coated with and without 9 mol% ZnO has been studied for cosmetic applications in sunscreens by a co-precipitation process using TiCl4 and Zn(NO3)2·6H2O as starting materials. XRD results show that the phases of anatase TiO2 and rutile TiO2 coexist for precursor powders without added ZnO (T-0Z) and calcined at 523 to 973 K for 2 h. When the T-0Z precursor powders are calcined at 1273 K for 2 h, only the rutile TiO2 appears. In addition, when the TiO2 precursor powders contain 9 mol% ZnO (T-9Z) are calcined at 873 to 973 K for 2 h, the crystallized samples are composed of the major phase of rutile TiO2 and the minor phases of anatase TiO2 and Zn2Ti3O8. The analyses of UV/VIS/NIR spectra reveal that the absorption of the T-9Z precursor powders after being calcined has a red-shift effect in the UV range with increasing calcination temperature. Therefore, the TiO2 nanocrystallite powders coated with 9 mol% ZnO can be used as the attenuate agent in the UV-A region for cosmetic applications in sunscreens. PMID:22408415

Effects of calcination temperature for rate capability of triple-shelled ZnFe2O4 hollow microspheres for lithium ion battery anodes

NASA Astrophysics Data System (ADS)

Hwang, Hojin; Shin, Haeun; Lee, Wan-Jin

2017-04-01

Triple-shelled ZnFe2O4 hollow microspheres (ZFO) as anode materials for lithium ion battery are prepared through a one-pot hydrothermal reaction using the composite solution consisting of sucrose in water and metal ions in ethylene glycol (EG), followed by different calcination processes. The architectures of ZFO micro spheres are differently synthesized through a mutual cooperation of inward and outward ripening with three different calcination temperatures. Thin triple-shelled ZnFe2O4 hollow microspheres calcined at 450 °C (ZFO-450) delivers a high reversible capacity of 932 mA h g-1 at a current density of 2 A g-1 even at the 200th cycle without obvious decay. Furthermore, ZFO-450 delivers 1235, 1005, 865, 834, and 845 mA h g-1 at high current densities of 0.5, 2, 5, 10, and 20 A g-1 after 100 cycles. Thin triple-shelled hollow microsphere prepared at an optimum calcination temperature provides exceptional rate capability and outstanding rate retention due to (i) the formation of nanoparticles leading to thin shell with morphological integrity, (ii) the facile mass transfer by thin shell with mesoporous structure, and (iii) the void space with macroporous structure alleviating volume change occurring during cycling.

Effects of calcination temperature for rate capability of triple-shelled ZnFe2O4 hollow microspheres for lithium ion battery anodes

PubMed Central

Hwang, Hojin; Shin, Haeun; Lee, Wan-Jin

2017-01-01

Triple-shelled ZnFe2O4 hollow microspheres (ZFO) as anode materials for lithium ion battery are prepared through a one-pot hydrothermal reaction using the composite solution consisting of sucrose in water and metal ions in ethylene glycol (EG), followed by different calcination processes. The architectures of ZFO micro spheres are differently synthesized through a mutual cooperation of inward and outward ripening with three different calcination temperatures. Thin triple-shelled ZnFe2O4 hollow microspheres calcined at 450 °C (ZFO-450) delivers a high reversible capacity of 932 mA h g−1 at a current density of 2 A g−1 even at the 200th cycle without obvious decay. Furthermore, ZFO-450 delivers 1235, 1005, 865, 834, and 845 mA h g−1 at high current densities of 0.5, 2, 5, 10, and 20 A g−1 after 100 cycles. Thin triple-shelled hollow microsphere prepared at an optimum calcination temperature provides exceptional rate capability and outstanding rate retention due to (i) the formation of nanoparticles leading to thin shell with morphological integrity, (ii) the facile mass transfer by thin shell with mesoporous structure, and (iii) the void space with macroporous structure alleviating volume change occurring during cycling. PMID:28418001

Process for preparing fine grain silicon carbide powder

DOEpatents

Wei, G.C.

Finely divided silicon carbide powder is obtained by mixing colloidal silica and unreacted phenolic resin in either acetone or methanol, evaporating solvent from the obtained solution to form a gel, drying and calcining the gel to polymerize the phenolic resin therein, pyrolyzing the dried and calcined gel at a temperature in the range of 500 to 1000/sup 0/C, and reacting silicon and carbon in the pyrolyzed gel at a temperature in the range of 1550 to 1700/sup 0/C to form the powder.

Processing Studies for Optically Transparent La(2)O(3)-Doped Y(2)O(3).

DTIC Science & Technology

1986-07-31

sintering. EXPERIMENTAL PROCEDURE ’ "’ The control powder (A) used in this investigation was prepared by a standard oxalate coprecip- itation procedure...Possible sources of CO2 are the decomposition of any oxalate remaining after calcination and/or formation of ’.’ carbonates during exposure to air. The...all the volatiles are removed from oxalate -derived powders during calcining or prefiring to 15000C. C02 is the major species present and probably

An Efficient, Solvent-Free Process for Synthesizing Anhydrous MgCl 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Motkuri, Radha K.; Vemuri, Venkata Rama S.; Barpaga, Dushyant

A new efficient and solvent-free method for the synthesis of anhydrous MgCl2 from its hexahydrate is proposed. Fluidized dehydration of MgCl 2·6H 2O feedstock at 200 °C in a porous bed reactor yields MgCl2·nH2O (0 < n < 1), which has a similar diffraction pattern as activated MgCl2. The MgCl 2·nH 2O is then ammoniated directly using liquefied NH 3 in the absence of solvent to form MgCl 2·6NH 3. Calcination of the hexammoniate complex at 300 °C then yields anhydrous MgCl 2. Both dehydration and deammoniation were thoroughly studied using in situ as well as ex situ characterization techniques.more » Specifically, a detailed understanding of the dehydration process was monitored by in situ PXRD and in situ FTIR techniques where formation of salt with nH 2O (n = 4, 2, 1, <1) was characterized. Given the reduction in thermal energy required to produce dehydrated feedstock with this method compared with current strategies, significant cost benefits are expected. Overall, the combined effect of activation, macroporosity, and coordinated water depletion allows the formation of hexammoniate without using solvent, thus minimizing waste formation.« less

The Influence of Alumina Properties on its Dissolution in Smelting Electrolyte

NASA Astrophysics Data System (ADS)

Bagshaw, A. N.; Welch, B. J.

The dissolution of a wide range of commercially produced aluminas in modified cryolite bath was studied on a laboratory scale. Most of the aluminas were products of conventional refineries and smelter dry scrubbing systems; a few were produced in laboratory and pilot calciners, enabling greater flexibility in the calcination process and the final properties. The mode of alumina feeding and the size of addition approximated to the point feeder situation. Alpha-alumina content, B.E.T. surface area and median particle size had little impact on dissolution behaviour. The volatiles content, expressed as L.O.I., the morphology of the original hydrate and the mode of calcination had the most influence. Discrete intermediate oxide phases were identified in all samples; delta-alumina content impacted most on dissolution. The flow properties of an alumina affected its overall dissolution.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zheng Jun; Liu Jing; Lv Dongping

The porous hierarchical spherical Co{sub 3}O{sub 4} assembled by nanosheets have been successfully fabricated. The porosity and the particle size of the product can be controlled by simply altering calcination temperature. SEM, TEM and SAED were performed to confirm that mesoporous Co{sub 3}O{sub 4} nanostructures are built-up by numerous nanoparticles with random attachment. The BET specific surface area and pore size of the product calcined at 280 deg. C are 72.5 m{sup 2} g{sup -1} and 4.6 nm, respectively. Our experiments further demonstrated that electrochemical performances of the synthesized products working as an anode material of lithium-ion battery are stronglymore » dependent on the porosity. - Graphical abstract: The flower-like Co{sub 3}O{sub 4} porous spheres with hierarchical structure have been successfully prepared via a simple calcination process using cobalt hydroxide as precursor.« less

Arsenic removal from aqueous solutions using Fe3O4-HBC composite: effect of calcination on adsorbents performance.

PubMed

Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

2014-01-01

The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g(-1) and 3.07 mg g(-1), respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4-10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water.

Arsenic Removal from Aqueous Solutions Using Fe3O4-HBC Composite: Effect of Calcination on Adsorbents Performance

PubMed Central

Baig, Shams Ali; Sheng, TianTian; Sun, Chen; Xue, XiaoQin; Tan, LiSha; Xu, XinHua

2014-01-01

The presence of elevated concentration of arsenic in water sources is considered to be health hazard globally. Calcination process is known to change the surface efficacy of the adsorbent. In current study, five adsorbent composites: uncalcined and calcined Fe3O4-HBC prepared at different temperatures (400°C and 1000°C) and environment (air and nitrogen) were investigated for the adsorptive removal of As(V) and As(III) from aqueous solutions determining the influence of solution's pH, contact time, temperature, arsenic concentration and phosphate anions. Characterizations from FTIR, XRD, HT-XRD, BET and SEM analyses revealed that the Fe3O4-HBC composite at higher calcination temperature under nitrogen formed a new product (fayalite, Fe2SiO4) via phase transformation. In aqueous medium, ligand exchange between arsenic and the effective sorbent site ( = FeOOH) was established from the release of hydroxyl group. Langmuir model suggested data of the five adsorbent composites follow the order: Fe3O4-HBC-1000°C(N2)>Fe3O4-HBC (uncalcined)>Fe3O4-HBC-400°C(N2)>Fe3O4-HBC-400°C(air)>Fe3O4-HBC-1000°C(air) and the maximum As(V) and As(III) adsorption capacities were found to be about 3.35 mg g−1 and 3.07 mg g−1, respectively. The adsorption of As(V) and As(III) remained stable in a wider pH range (4–10) using Fe3O4-HBC-1000°C(N2). Additionally, adsorption data fitted well in pseudo-second-order (R 2>0.99) rather than pseudo-first-order kinetics model. The adsorption of As(V) and As(III) onto adsorbent composites increase with increase in temperatures indicating that it is an endothermic process. Phosphate concentration (0.0l mM or higher) strongly inhibited As(V) and As(III) removal through the mechanism of competitive adsorption. This study suggests that the selective calcination process could be useful to improve the adsorbent efficiency for enhanced arsenic removal from contaminated water. PMID:24967645

Role of manganese dioxide in the recovery of oxide-sulphide zinc ore.

PubMed

Yang, Kun; Zhang, Libo; Zhu, Xingcai; Peng, Jinhui; Li, Shiwei; Ma, Aiyuan; Li, Haoyu; Zhu, Fei

2018-02-05

In this article, the role of MnO 2 in the recovery of oxide-sulphide zinc ore discussed. Through adopting various modern analysis techniques (such as X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope, energy dispersive X-ray analysis, and fourier transform infrared spectroscopy), the function and mechanism of MnO 2 during the phase transformation process is found out. Thermodynamic mechanisms involved in the phase transformation process with or without addition of manganese dioxide investigated by exploiting the Equilib module of FactSage. What's more, XRD patterns, XPS spectra and SEM-EDAX analyses of zinc calcines verify well the calculations of FactSage. Results reveal that the addition of MnO 2 will produce an aggregation of ZnMn 2 O 4 , a valuable energy material, while roasting on its own, results in generating undesirable Zn 2 SiO 4 , the oxidation degree being relatively low. Moreover, XRD pattern of zinc calcine and FT-IR spectrum of yellow product collected in the calcination process prove that the sulphur-fixing value of the additive MnO 2 , which can promote transforming to the elemental sulphur. The volatile S can be collected through a simple guiding device. In this process, the emission of SO 2 effectively avoids, thus MnO 2 deems as a potential additive in the recovery of oxide-sulphide zinc ore. Copyright © 2017. Published by Elsevier B.V.

Humate-assisted Synthesis of MoS2/C Nanocomposites via Co-Precipitation/Calcination Route for High Performance Lithium Ion Batteries

NASA Astrophysics Data System (ADS)

Geng, Qin; Tong, Xin; Wenya, Gideon Evans; Yang, Chao; Wang, Jide; Maloletnev, A. S.; Wang, Zhiming M.; Su, Xintai

2018-04-01

A facile, cost-effective, non-toxic, and surfactant-free route has been developed to synthesize MoS2/carbon (MoS2/C) nanocomposites. Potassium humate consists of a wide variety of oxygen-containing functional groups, which is considered as promising candidates for functionalization of graphene. Using potassium humate as carbon source, two-dimensional MoS2/C nanosheets with irregular shape were synthesized via a stabilized co-precipitation/calcination process. Electrochemical performance of the samples as an anode of lithium ion battery was measured, demonstrating that the MoS2/C nanocomposite calcinated at 700 °C (MoS2/C-700) electrode showed outstanding performance with a high discharge capacity of 554.9 mAh g- 1 at a current density of 100 mA g- 1 and the Coulomb efficiency of the sample maintained a high level of approximately 100% after the first 3 cycles. Simultaneously, the MoS2/C-700 electrode exhibited good cycling stability and rate performance. The success in synthesizing MoS2/C nanocomposites via co-precipitation/calcination route may pave a new way to realize promising anode materials for high-performance lithium ion batteries.

Preparation of Calcined Zirconia-Carbon Composite from Metal Organic Frameworks and Its Application to Adsorption of Crystal Violet and Salicylic Acid

PubMed Central

Hasan, Zubair; Cho, Dong-Wan; Nam, In-Hyun; Chon, Chul-Min; Song, Hocheol

2016-01-01

Zirconia-carbon (ZC) composites were prepared via calcination of Zr-based metal organic frameworks, UiO-66 and amino-functionalized UiO-66, under N2 atmosphere. The prepared composites were characterized using a series of instrumental analyses. The surface area of the ZC composites increased with the increase of calcination temperature, with the formation of a graphite oxide phase observed at 900 °C. The composites were used for adsorptive removal of a dye (crystal violet, CV) and a pharmaceutical and personal care product (salicylic acid, SA). The increase of the calcination temperature resulted in enhanced adsorption capability of the composites toward CV. The composite calcined at 900 °C exhibited a maximum uptake of 243 mg·g−1, which was much greater than that by a commercial activated carbon. The composite was also effective in SA adsorption (102 mg·g−1), and N-functionalization of the composite further enhanced its adsorption capability (109 mg·g−1). CV adsorption was weakly influenced by solution pH, but was more dependent on the surface area and pore volume of the ZC composite. Meanwhile, SA adsorption showed strong pH dependence, which implies an active role of electrostatic interactions in the adsorption process. Base-base repulsion and hydrogen bonding are also suggested to influence the adsorption of CV and SA, especially for the N-functionalized composite. PMID:28773387

Comparative study of phase transition and textural changes upon calcination of two commercial titania samples: A pure anatase and a mixed anatase-rutile

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kordouli, Eleana; Dracopoulos, Vassileios; Vaimakis, Tiverios

2015-12-15

The effect of calcination temperature and time on structural and textural changes of two commercial TiO{sub 2} samples (pure anatase and a mixture of anatase and rutile) has been investigated using N{sub 2} physisorption, ex-situ and in-situ X-ray powder diffraction, differential scanning calorimetry and UV–vis diffuse reflectance spectroscopy. The increase of the calcination temperature (up to 700 °C) and time (up to 8 h) causes only textural changes in the pure anatase, whereas a transformation of the anatase to rutile takes place, in addition, in the mixed titania (containing anatase and rutile). The textural changes observed in pure anatase samplemore » were attributed to solid state diffusion leading to an increase in the size of anatase nanocrystals, through sintering. Thus, the mean pore diameter shifts to higher values and the pore volume and specific surface area decrease. The successful application of the Johnson–Mehl–Avrami–Kolmogorov model in the kinetic data concerning the pure anatase indicates a mass transfer control of sintering process. Similar textural changes were also observed upon calcination of the sample containing anatase and rutile. In this case not only sintering but the anatase to rutile transformation contributes also to the textural changes. Kinetic analysis showed that the rutile nanocrystals in the mixed titania served as seed for by-passing the high energy barrier nucleation step allowing/facilitating thus the anatase to rutile transformation. A fine control of the anatase to rutile ratio and thus of energy-gap and the population of hetero-junctions may be obtained by adjusting the calcination temperature and time. - Graphical Abstract: Dependence of anatase content of P25 on the calcination temperature (600 °C (■), 650 °C (●), 700 °C (▲)) and time. - Highlights: • Increase of calcination temperature up to 800 °C and time up to 8 h causes only textural changes in pure anatase • Progressive transformation of anatase to rutile with time takes place in the mixed titania above 600 °C • A high activation energy barrier inhibits the solid state transformation in pure anatase • Rutile nanocrystals in mixed titania serve as seeding for favouring transformation • Calcination temperature and time allow a fine control of E{sub g} and heterojunctions population in mixed titania.« less

In Vitro Studies Evaluating Leaching of Mercury from Mine Waste Calcine Using Simulated Human Body Fluids

PubMed Central

2010-01-01

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almadén, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 μg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 μg of Hg leached/g), serum-based fluid (as much as 1600 μg of Hg leached/g), and water of pH 5 (as much as 880 μg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway. PMID:20491469

In vitro studies evaluating leaching of mercury from mine waste calcine using simulated human body fluids.

PubMed

Gray, John E; Plumlee, Geoffrey S; Morman, Suzette A; Higueras, Pablo L; Crock, James G; Lowers, Heather A; Witten, Mark L

2010-06-15

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almaden, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 microg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 microg of Hg leached/g), serum-based fluid (as much as 1600 microg of Hg leached/g), and water of pH 5 (as much as 880 microg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway.

In vitro studies evaluating leaching of mercury from mine waste calcine using simulated human body fluids

USGS Publications Warehouse

Gray, John E.; Plumlee, Geoffrey S.; Morman, Suzette A.; Higueras, Pablo L.; Crock, James G.; Lowers, Heather A.; Witten, Mark L.

2010-01-01

In vitro bioaccessibility (IVBA) studies were carried out on samples of mercury (Hg) mine-waste calcine (roasted Hg ore) by leaching with simulated human body fluids. The objective was to estimate potential human exposure to Hg due to inhalation of airborne calcine particulates and hand-to-mouth ingestion of Hg-bearing calcines. Mine waste calcines collected from Hg mines at Almadén, Spain, and Terlingua, Texas, contain Hg sulfide, elemental Hg, and soluble Hg compounds, which constitute primary ore or compounds formed during Hg retorting. Elevated leachate Hg concentrations were found during calcine leaching using a simulated gastric fluid (as much as 6200 μg of Hg leached/g sample). Elevated Hg concentrations were also found in calcine leachates using a simulated lung fluid (as much as 9200 μg of Hg leached/g), serum-based fluid (as much as 1600 μg of Hg leached/g), and water of pH 5 (as much as 880 μg of Hg leached/g). The leaching capacity of Hg is controlled by calcine mineralogy; thus, calcines containing soluble Hg compounds contain higher leachate Hg concentrations. Results indicate that ingestion or inhalation of Hg mine-waste calcine may lead to increased Hg concentrations in the human body, especially through the ingestion pathway.

PROCESS FOR RECOVERY OF CONSTITUENTS OF ORES

DOEpatents

McCullough, R.F.

1959-05-01

A process for U recovery from leached zone material is described. Calcination with alkali metal carbonate at 600 to 2000 deg F followed by digestion with H/sub 2/SO/sub 4/ and filtration forms the basis of the process. (T.R.H.)

Synthesis of zirconium dioxide by ultrasound assisted precipitation: effect of calcination temperature.

PubMed

Prasad, Krishnamurthy; Pinjari, D V; Pandit, A B; Mhaske, S T

2011-09-01

Nanostructured zirconium dioxide was synthesized from zirconyl nitrate using both conventional and ultrasound assisted precipitation in alkaline medium. The synthesized samples were calcinated at temperatures ranging from 400°C to 900°C in steps of 100°C. The ZrO(2) specimens were characterized using X-ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The thermal characteristics of the samples were studied via Differential Scanning Calorimetry-Thermo-Gravimetry Analysis (DSC-TGA). The influence of the calcination temperature on the phase transformation process from monoclinic to tetragonal to cubic zirconia and its consequent effect on the crystallite size and % crystallinity of the synthesized ZrO(2) was studied and interpreted. It was observed that the ultrasound assisted technique helped to hasten to the phase transformation and also at some point resulted in phase stabilization of the synthesized zirconia. Copyright © 2011 Elsevier B.V. All rights reserved.

Utilization of wasted cockle shell as a natural coagulant and a neutralizer of polluted water in Bangka Belitung islands, Indonesia

NASA Astrophysics Data System (ADS)

Tiandho, Y.; Aldila, H.; Mustari; Megiyo; Afriani, F.

2018-05-01

Bangka Belitung Islands is the largest tin producer in Indonesia. The high activity of tin mining caused the environmental damage which had an impact on the emergence of clean water crisis in some areas in this province. In this paper, a simple water quality improvement method based on wasted cockle shell was developed. Based on x-ray diffraction analysis it is known that calcination of cockle shell powder at 700°C will decompose the powder into calcium oxide compound. The addition of calcined cockle shell powder into acidic water from Merawang Sub-district will increase the pH of water through the process of forming hydroxide groups in the water. The calcined cockle shell powder can also coagulate pollutants in some polluted water from Koba Sub-district. The coagulation results were analyzed using SEM/EDS.

Cyclic carbonation calcination studies of limestone and dolomite for CO{sub 2} separation from combustion flue gases - article no. 011801

DOE Office of Scientific and Technical Information (OSTI.GOV)

Senthoorselvan, S.; Gleis, S.; Hartmut, S.

2009-01-15

Naturally occurring limestone and dolomite samples, originating from different geographical locations, were tested as potential sorbents for carbonation/calcination based CO{sub 2} capture from combustion flue gases. Samples have been studied in a thermogravimetric analyzer under simulated flue gas conditions at three calcination temperatures, viz., 750{sup o}C, 875{sup o}C, and 930{sup o}C for four carbonation calcination reaction (CCR) cycles. The dolomite sample exhibited the highest rate of carbonation than the tested limestones. At the third cycle, its CO{sub 2} capture capacity per kilogram of the sample was nearly equal to that of Gotland, the highest reacting limestone tested. At the fourthmore » cycle it surpassed Gotland, despite the fact that the CaCO{sub 3} content of the Sibbo dolomite was only 2/3 of that of the Gotland. Decay coefficients were calculated by a curve fitting exercise and its value is lowest for the Sibbo dolomite. That means, most probably its capture capacity per kilogram of the sample would remain higher well beyond the fourth cycle. There was a strong correlation between the calcination temperature, the specific surface area of the calcined samples, and the degree of carbonation. It was observed that the higher the calcination temperature, the lower the sorbent reactivity. For a given limestone/dolomite sample, sorbents CO{sub 2} capture capacity depended on the number of CCR cycles and the calcination temperature. According to the equilibrium thermodynamics, the CO{sub 2} partial pressure in the calciner should be lowered to lower the calcination temperature. This can be achieved by additional steam supply into the calciner. Steam could then be condensed in an external condenser to single out the CO{sub 2} stream from the exit gas mixture of the calciner. A calciner design based on this concept is illustrated.« less

Environmental evaluation of alternatives for long-term management of Defense high-level radioactive wastes at the Idaho Chemical Processing Plant

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1982-09-01

The U.S. Department of Energy (DOE) is considering the selection of a strategy for the long-term management of the defense high-level wastes at the Idaho Chemical Processing Plant (ICPP). This report describes the environmental impacts of alternative strategies. These alternative strategies include leaving the calcine in its present form at the Idaho National Engineering Laboratory (INEL), or retrieving and modifying the calcine to a more durable waste form and disposing of it either at the INEL or in an offsite repository. This report addresses only the alternatives for a program to manage the high-level waste generated at the ICPP. 24more » figures, 60 tables.« less

Calcination and solid state reaction of ceramic-forming components to provide single-phase superconducting materials having fine particle size

DOEpatents

Balachandran, Uthamalingam; Poeppel, Roger B.; Emerson, James E.; Johnson, Stanley A.

1992-01-01

An improved method for the preparation of single phase, fine grained ceramic materials from precursor powder mixtures where at least one of the components of the mixture is an alkali earth carbonate. The process consists of heating the precursor powders in a partial vacuum under flowing oxygen and under conditions where the partial pressure of CO.sub.2 evolved during the calcination is kept to a very low level relative to the oxygen. The process has been found particularly suitable for the preparation of high temperature copper oxide superconducting materials such as YBa.sub.2 Cu.sub.3 O.sub.x "123" and YBa.sub.2 Cu.sub.4 O.sub.8 "124".

Enrichment process of biogas using simultaneous Absorption - Adsorption methods

NASA Astrophysics Data System (ADS)

Kusrini, Eny; Lukita, Maya; Gozan, Misri; Susanto, Bambang Heru; Nasution, Dedy Alharis; Rahman, Arif; Gunawan, Cindy

2017-03-01

Removal of CO2 in biogas is an essential methods to the purification and upgrading of biogas. Natural Clinoptilolite zeolites were evaluated as sorbents for purification of biogas that produced from palm oil mill effluent (POME) by anerobic-digestion method. The absorption and adsorption experiments were conducted in a fixed-bed two column adsorption unit by simultaneous absorption-adsorption method. The Ca(OH)2 solution with concentration of 0.062 M was used as absorption method. Sorbent for removal of CO2 in biogas have been prepared by modifying of Clinoptilolite zeolites with an acid (HCl, 2M) and alkaline (NaOH, 2M), calcined at 450°C and then coated using chitosan (0.5 w/v%) in order to increase their adsorption capacity. The removal of CO2 in biogas was achieved about ˜83% using 2.5 g of sorbent zeolite (2M)/chitosan dosage for each column, breakthrough time of 30 min, and flow rate of 100 mL/min. Clinoptilolite zeolites with modifications of an acid-alkaline and chitosan (zeolite (2M)/chitosan) are promising sorbents due to the amine groups from chitosan and high surface-volume ratio are one of important factors in a simultaneous absorption-adsorption method.

Investigation of the influence of vanadium, iron and nickel dopants on the morphology, and crystal structure and photocatalytic properties of titanium dioxide based nanopowders.

PubMed

Shao, Godlisten N; Jeon, Sun-Jeong; Haider, M Salman; Abbass, Nadir; Kim, Hee Taik

2016-07-15

Photoactive V, Fe and Ni doped TiO2 (M-TiO2) nanopowders were synthesized by a modified two-step sol-gel process in the absence of additives. Titanium oxychloride, which is a rarely-used TiO2 precursor was used to yield M-TiO2 photocatalysts with preferential photochemical performance in the presence of natural solar irradiation. The obtained samples were calcined at different calcination temperatures ranging from 450 to 800°C to evaluate the influence of the sintering on the physicochemical properties. The properties of the obtained samples were examined by XRF, XRD, Raman spectroscopy, UV-visible DRS, XPS, nitrogen gas physisorption studies, SEM-EDAX and HRTEM analyses. Structural characterization of the samples revealed the incorporation of these transition metal element into TiO2. It was also depicted that the morphology, crystal structure, optical and photochemical properties of the obtained samples were largely dependent on the calcination temperature and the type of dopant used during the preparation process. The photochemical performance of the samples was investigated in the photodegradation of methylene blue in the presence of natural sunlight. The experimental results indicated that the VT600 sample possessed the highest activity due to its superior properties. This study provides a systematic preparation and selection of the precursor, dopant and calcination temperature that are suitable for the formation of TiO2-based heterogeneous photocatalysts with appealing morphology, crystal structure, optical and photochemical properties for myriad of applications. Copyright © 2016 Elsevier Inc. All rights reserved.

Extraction of caustic potash from spent tea for biodiesel Production

NASA Astrophysics Data System (ADS)

Sulaiman, Sarina; Faiz Che Fisol, Ahmad; Sharikh, Atikah Mohamed; Noraini Jimat, Dzun; Jamal, Parveen

2018-01-01

Biodiesel is an alternative to non-renewable fossil fuels due to its low gas emission and economical value. This study aims to extract caustic potash (KOH) from spent tea and to optimize the transesterfication process based on parameters such as amount of catalyst, reaction temperature and methanol to oil ratio. The spent tea was first dried at 60°C prior to calcination at 600°C for two hours. Caustic Potash were extracted from the calcined spent tea. The transesterification process was done based on Design of Experiments (DOE) to study the effects of amount of catalyst ranging from 0.5 wt % to 2.5 wt %, reaction temperature from 55°C to 65°C and methanol to oil ratio from 6:1 to 12:1 at a constant agitation rate of 300 rpm for three hours. The calcined spent tea produced was recorded the highest at 54.3 wt % and the extracted catalyst was 2.4 wt %. The optimized biodiesel yield recorded was 56.95% at the optimal conditions of 2.5 wt % amount of catalyst, 65°C reaction temperature and 9:1 methanol to oil ratio.

The influence of ozone on the photocatalytic degradation of phenol using TiO2 photocatalyst supported by Bayah natural zeolite

NASA Astrophysics Data System (ADS)

Sulaiman, Fatah; Sari, Denni Kartika; Kustiningsih, Indar

2017-05-01

Effect of ozone on the photocatalytic degradation of phenol using TiO2 photocatalyst which supported Bayah Natural Zeolite has been investigated. Phenol (merk Pro analys) was used as waste solution. TiO2 photocatalyst was obtained from Titanium isopropoxide using sol gel method which supported by Bayah Natural Zeolite. The influence of temperature of calcination and catalyst loading have been conducted. The calcination temperature of photocatalyst was 450°C, 500°C, 550°C dan 600°C while the catalyst loading of 0,1g/L; 0,3 g/L; 0,6 g/L; 1 g/L dan 1,2 g/L. Analysis of phenol concentration was used Hach Spechtrophotometer. To determine the effect of ozone on photocatalytic degradation during process ozone was flowed into reactor. The result showed the optimum calcination temperature was obtained at 500°C. The optimum catalyst loading to degrade the phenolic compounds was equal to 1g/L. In these optimum condition the conversion of phenol degradation was 87% after 5 hours. By adding ozone during the degradation process, the conversion reached 100% after 2 hours.

Characterization of raw and burnt oil shale from Dotternhausen: Petrographical and mineralogical evolution with temperature

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thiéry, Vincent, E-mail: vincent.thiery@mines-douai.fr; Université de Lille; Bourdot, Alexandra, E-mail: alexandra.bourdot@gmail.com

The Toarcian Posidonia shale from Dotternhausen, Germany, is quarried and burnt in a fluidized bed reactor to produce electricity. The combustion residue, namely burnt oil shale (BOS), is used in the adjacent cement work as an additive in blended cements. The starting material is a typical laminated oil shale with an organic matter content ranging from 6 to 18%. Mineral matter consists principally of quartz, feldspar, pyrite and clays. After calcination in the range, the resulting product, burnt oil shale, keeps the macroscopic layered texture however with different mineralogy (anhydrite, lime, iron oxides) and the formation of an amorphous phase.more » This one, studied under STEM, reveals a typical texture of incipient partial melting due to a long retention time (ca. 30 min) and quenching. An in-situ high temperature X-ray diffraction (HTXRD) allowed studying precisely the mineralogical changes associated with the temperature increase. - Highlights: • We present oil shale/burnt oil shale characterization. • The Posidonia Shale is burnt in a fluidized bed. • Mineralogical evolution with temperature is complex. • The burnt oil shale is used in composite cements.« less

Is there lattice contraction in multicomponent metal oxides? Case study for GdVO4:Eu3+ nanoparticles.

PubMed

Yang, Liusai; Li, Liping; Zhao, Minglei; Fu, Chaochao; Li, Guangshe

2013-08-02

Metal oxide nanomaterials have been found to have great potential for diverse applications due to their unique relationships between structure and properties. Lattice expansion as particle size reduces was previously considered to be general for metal oxide nanomaterials. It is now a great challenge to see if lattice contraction could be induced by the size effect for metal oxide nanomaterials. ABO4 metal oxides (e.g., CaWO4, GdVO4, and CdWO4) are some of the most important functional materials with many applications, while such oxides at the nanoscale are never reported to show a lattice contraction. This work presents a first report on the variation from lattice expansion to lattice contraction by tuning the microstructures of GdVO4:Eu(3+) nanocrystals. A hydrothermal method was adopted to synthesize GdVO4:Eu(3+) nanocrystals, and then these nanoparticles were calcined at 600 ° C in air. It is found that particle size reduction led to a lattice contraction for the calcined samples, which is in contrast to the lattice expansion observed for the hydrothermally synthesized counterparts or many other metal oxide nanomaterials. In addition, the lattice symmetry of the calcined samples remained almost a constant. The results indicate that the negative surface stress was eliminated by calcination treatment, leading to a homogeneous compression process in the lattice structure of the calcined GdVO4:Eu(3+) nanocrystals. Furthermore, Eu(3+) was taken as a structural probe and a luminescence center to study the local environments pertinent to these structural changes and to optimize the photoluminescence performance.

The effect of calcination conditions on the graphitizability of novel synthetic and coal-derived cokes

NASA Astrophysics Data System (ADS)

Bennett, Barbara Ellen

The effects of calcination heating rate and ultimate calcination temperature upon calcined coke and subsequent graphitic material microstructures were studied for materials prepared from three different precursors. The pitch precursors used were Mitsubishi AR pitch (a synthetic, 100% mesophase pitch), the NMP-extracted portion of a raw coal, and the NMP-extracted fraction of a coal liquefaction residue obtained from an HTI pilot plant. These materials were all green-coked under identical conditions. Optical microscopy confirmed that the Mitsubishi coke was very anisotropic and the HTI coke was nearly as anisotropic. The coke produced from the direct coal extract was very isotropic. Crystalline development during calcination heating was verified by high-temperature x-ray diffraction. Experiments were performed to ascertain the effects of varying calcination heating rate and ultimate temperature. It was determined that calcined coke crystallite size increased with increasing temperature for all three materials but was found to be independent of heating rate. The graphene interplanar spacing decreased with increasing temperature for the isotropic NMP-extract material but increased with increasing temperature for the anisotropic materials---Mitsubishi and HTI cokes. Graphene interplanar spacing was also found to be independent of heating rate. Calcined coke real densities were, likewise, found to be independent of heating rate. The anisotropic cokes (Mitsubishi and HTI) exhibited increasing real density with increasing calcination temperature. The NMP-extract coke increased in density up to 1050°C and then suffered a dramatic reduction in real density when heated to 1250°C. This is indicative of puffing. Since there was no corresponding disruption in the crystalline structure, the puffing phenomena was determined to be intercrystalline rather than intracrystalline. After the calcined cokes were graphitized (under identical conditions), the microstructures were re-evaluated. The crystalline properties of the graphitic materials appeared to be independent of calcination conditions---both heating rate and final temperature---for all samples prepared from any given precursor. The calcination step did not influence the microstructure or graphitizability of any of the three materials. The crystallinity of a graphitic material appears to be dictated by the properties of the green coke and cannot be altered by manipulating calcination conditions.

Effect of calcination temperature on structural and photocatalyst properties of nanofibers prepared from low-cost natural ilmenite mineral by simple hydrothermal method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simpraditpan, Athapon; Wirunmongkol, Thanakorn; Pavasupree, Sorapong, E-mail: sorapongp@yahoo.com

2013-09-01

Graphical abstract: - Highlights: • Nanofibers were prepared from low-cost ilmenite mineral via simple hydrothermal. • High photocatalyst nanofibers were prepared via post heat treatment method. • The nanofibers calcined at 100–700 °C for 2 h maintained nanofiber structure. • The calcined nanofibers at 400 °C showed the highest photocatalytic activity. - Abstract: Titanate nanofibers were synthesized via the hydrothermal method (120 °C for 72 h) using natural ilmenite mineral (FeTiO{sub 3}) as the starting material. The samples were characterized by X-ray diffraction (XRD), X-ray fluorescent (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and Brunauer–Emmett–Teller (BET) for specificmore » surface area. The nanofibers were 20–90 nm in diameter and 2–7 μm in length. The as-synthesized nanofibers calcined at 300–400 °C showed TiO{sub 2} (B) whereas the nanofibers calcined at 500 °C revealed a mixture of two phases of TiO{sub 2} (B) and anatase. The nanofibers calcined at high temperature of 600–1000 °C showed a mixture of tri-crystalline of anatase, rutile, and Fe{sub 2}O{sub 3}. The rutile phase increased with increasing calcination temperature. The nanofibers calcined at 300–700 °C maintained their structure while the morphology of the nanofibers calcined at 800–1000 °C transformed into submicron rod-like structure. This increase of calcination temperature led to the phase transformation from thermodynamically metastable anatase to the most stable form of rutile phase. The crystallite size of prepared samples increased with increasing calcination temperature. Interestingly, with increasing calcination temperature, the absorption edge of the prepared samples shows an obvious shift to visible light region due to the change of crystallite phase and increased crystallite size. Therefore, the band gap energy of the prepared samples became narrower with increasing calcination temperature. Furthermore, the photocatalytic activity of the nanofibers calcined at 400 °C for 2 h was found to be not merely higher than those of the commercially available TiO{sub 2} nanoparticles powders (P-25, JRC-01, and JRC-03) but also the highest of all the samples in this study.« less

Effect of calcination temperature on microstructure and magnetic properties of Ni{sub 0.5}Zn{sub 0.25}Cu{sub 0.25} Fe{sub 2}O{sub 4} nanoparticles synthesized by sol-gel method

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pransisco, Prengki, E-mail: prengkipransisco@gmail.com, E-mail: afza@petronas.com.my; Shafie, Afza, E-mail: prengkipransisco@gmail.com, E-mail: afza@petronas.com.my; Guan, Beh Hoe, E-mail: beh.hoeguan@petronas.com.my

2014-10-24

This paper examines the effect of calcination process on the structural and magnetic properties material nanostructure composite of Ni{sub 0Ð}œ‡{sub 5}Zn{sub 0Ð}œ‡{sub 25}Cu{sub 0.25} Fe{sub 2}O{sub 4} ferrites. The samples were successfully prepared by sol-gel method at different calcination temperature, which are 600°C, 700°C, 800°C and 900°C. Morphological investigation, average crystallite size and microstructure of the material were examined by using X-ray diffraction (XRD) and confirmed by high resolution transmission electron microscope (HRTEM) and field emission scanning electron microscope (FESEM). The effects of calcination temperature on the magnetic properties were calculated by using vibrating sample magnetometer (VSM). The XRD resultmore » shows single-phase cubic spinel structure with interval average size 5.9-38 nm, and grain size microstructure of the material was increasing with temperature increases. The highest magnetization saturation was reached at a temperature 800°C with value 53.89 emu/g, and the value coercive force (Hc) was inversely with the grain size.« less

Green synthesis and characterization of ANbO3 (A = Na, K) nanopowders fabricated using a biopolymer

NASA Astrophysics Data System (ADS)

Khorrami, Gh. H.; Mousavi, M.; Khayatian, S. A.; Kompany, A.; Khorsand Zak, A.

2017-10-01

Lead-free sodium niobate (NaNbO3, NN) and potassium niobate (KNbO3, KN) nanopowders were successfully synthesized by a simple and green synthesis process in gelatin media. Gelatin, which is a biopolymer, was used as stabilizer. In order to determine the lowest calcination temperature needed to obtain pure NN and KN nanopowders, the produced gels were analyzed by thermogravometric analyzer (TGA). The produced gels were calcined at 500∘C and 600∘C. The structural and optical properties of the prepared powders were examined using X-ray diffraction (XRD) technique, transmission electron microscopy (TEM), and UV-Vis spectroscopy. The XRD results revealed that pure phase NN and KN nanopowders were formed at low temperature calcination of 500∘C and 600∘C, respectively. The Scherrer formula and size-strain plot (SSP) method were employed to estimate crystallite size and lattice strain of the samples. The TEM images show that the NN and KN samples calcined at 600∘C have cubic shape with an average particle size of 60.95 and 39.29 nm, respectively. The optical bandgap energy of the samples was calculated using UV-Vis diffused reflectance spectra of the samples and Kubelka-Munck relation.

STUDY ON SYNTHESIS AND EVOLUTION OF NANOCRYSTALLINE Mg4Ta2O9 BY AQUEOUS SOL-GEL PROCESS

NASA Astrophysics Data System (ADS)

Wu, H. T.; Yang, C. H.; Wu, W. B.; Yue, Y. L.

2012-06-01

Nanosized and highly reactive Mg4Ta2O9 were successfully synthesized by aqueous sol-gel method compared with conventional solid-state method. Ta-Mg-citric acid solution was first formed and then evaporated resulting in a dry gel for calcination in the temperature ranging from 600°C to 800°C for crystallization in oxygen atmosphere. The crystallization process from the gel to crystalline Mg4Ta2O9 was identified by thermal analysis and phase evolution of powders was studied using X-ray diffraction (XRD) technique during calcinations. Particle size and morphology were examined by transmission electron microscopy (TEM) and high resolution scanning electron microscopy (HR-SEM). The results revealed that sol-gel process showed great advantages over conventional solid-state method and Mg4Ta2O9 nanopowders with the size of 20-30 nm were obtained at 800°C.

Thermophilic bio-hydrogen production from corn-bran residue pretreated by calcined-lime mud from papermaking process.

PubMed

Zhang, Jishi; Zhang, Junjie; Zang, Lihua

2015-12-01

This study investigated the use of calcined-lime mud from papermaking process (CLMP) pretreatment to improve fermentative hydrogen yields from corn-bran residue (CBR). CBR samples were pretreated with different concentrations (0-15 g/L) of CLMP at 55°C for 48 h, prior to the thermophilic fermentation with heat-treated anaerobic sludge inoculum. The maximum hydrogen yield (MHY) of 338.91 ml/g-VS was produced from the CBR pretreated with 10 g/L CLMP, with the corresponding lag-phase time of 8.24h. Hydrogen yield increments increased from 27.76% to 48.07%, compared to the control. The CLMP hydrolyzed more cellulose, which provided adequate substrates for hydrogen production. Copyright © 2015 Elsevier Ltd. All rights reserved.

Thermal and Surface Evaluation on The Process of Forming a Cu2O/CuO Semiconductor Photocatalyst on a Thin Copper Plate

NASA Astrophysics Data System (ADS)

Zainul, R.; Oktavia, B.; Dewata, I.; Efendi, J.

2018-04-01

This research aims to investigate the process of forming a multi-scale copper oxide semiconductor (CuO/Cu2O) through a process of calcining a copper plate. The changes that occur during the formation of the oxide are thermally and surface evaluated. Evaluation using Differential Thermal Analysis (DTA) obtained by surface change of copper plate happened at temperature 380°C. Calcination of oxide formation was carried out at temperature 380°C for 1 hour. Surface evaluation process by using Scanning Electron Microscope (SEM) surface and cross-section, to determine diffusion of oxide formation on copper plate. The material composition is monitored by XRF and XRD to explain the process of structural and physical changes of the copper oxide plate formed during the heating process. The thickness of Cu plates used is 200-250 μm. SEM analysis results, the oxygen atom interruption region is in the range of 20-30 μm, and diffuses deeper during thermal oxidation process. The maximum diffusion depth of oxygen atoms reaches 129 μm.

Calcined Waste Storage at the Idaho Nuclear Technology and Engineering Center

DOE Office of Scientific and Technical Information (OSTI.GOV)

M. D. Staiger

2007-06-01

This report provides a quantitative inventory and composition (chemical and radioactivity) of calcined waste stored at the Idaho Nuclear Technology and Engineering Center. From December 1963 through May 2000, liquid radioactive wastes generated by spent nuclear fuel reprocessing were converted into a solid, granular form called calcine. This report also contains a description of the calcine storage bins.

Calcination Conditions on the Properties of Porous TiO2 Film

NASA Astrophysics Data System (ADS)

Zhang, Wenjie; Pei, Xiaobei; Bai, Jiawei; He, Hongbo

2014-03-01

Porous TiO2 films were deposited on SiO2 precoated glass-slides by sol-gel method using PEG1000 as template. The strongest XRD diffraction peak at 2θ = 25.3° is attributed to [101] plane of anatase TiO2 in the film. The increases of calcination temperature and time lead to stronger diffraction peak intensity. High transmittance and blue shift of light absorption edge are the properties of the film prepared at high calcination temperature. The average pore size of the films increases with the increasing calcination temperature as the result of TiO2 crystalline particles growing up and aggregation, accompanied with higher specific surface area. Photocatalytic activity of porous TiO2 films increases with the increasing calcination temperature. The light absorption edge of the films slightly moves to longer wavelength region along with the increasing calcination time. The mesoporous film calcinated at 500 °C for 2 h has the highest transmittance, the maximum surface area, and the maximum total pore volume. Consequently, the optimum degradation activity is achieved on the porous TiO2 film calcinated at 500 °C for 2 h.

Synthesis and Thermodynamic Stability of Ba2B‧B″O6 and Ba3B*B″2O9 Perovskites Using the Molten Salt Method

NASA Astrophysics Data System (ADS)

Meng, Wei; Virkar, Anil V.

1999-12-01

A number of mixed perovskites of the types Ba2B‧B″O6 (BaB‧1/2B″1/2O3) and Ba3B*B″2O9 (BaB*1/3B″2/3O3) where B‧=Gd, La, Nd, Sm, or Y; B″=Nb and B*=Ca were synthesized by a conventional calcination process, as well as by the molten salt method. The former consists of calcining appropriate mixtures of oxide or carbonate precursors in air at elevated temperatures (∼1250°C). The latter method consists of adding appropriate mixtures of oxide or carbonate precursors to a molten salt bath at relatively low temperatures (on the order of 300 to 500°C) so that the requisite compound is formed by dissolution-reprecipitation. X-ray diffraction confirmed the formation of a single-phase perovskite in each case with calcination at 1250°C. In a molten salt bath, however, all except Ba2LaNbO6 and Ba2NdNbO6 formed the perovskite structure. On the contrary, powders of Ba2LaNbO6 and Ba2NdNbO6 formed by a high-temperature calcination process readily decomposed when introduced into the molten salt bath. The formation of the requisite perovskite at a temperature as low as 350°C in a molten salt suggests that: (a) The perovskite is stable at 350°C. (b) The molten salt exhibits sufficient precursor solubility for the dissolution-reprecipitation process to occur in a reasonable time. Similarly, the decomposition of Ba2LaNbO6 and Ba2NdNbO6 in a molten salt bath shows that these materials are thermodynamically unstable at the temperature of the molten salt bath.

Effect of calcination routes on phase formation of BaTiO3 and their electronic and magnetic properties

NASA Astrophysics Data System (ADS)

Majumder, Supriyo; Choudhary, R. J.; Tripathi, M.; Phase, D. M.

2018-05-01

We have investigated the phase formation and correlation between electronic and magnetic properties of oxygen deficient BaTiO3 ceramics, synthesized by solid state reaction method, following different calcination paths. The phase analysis divulge that a higher calcination temperature above 1000° C is favored for tetragonal phase formation than the cubic phase. The core level X-ray photo electron spectroscopy measurements confirm the presence of oxygen vacancies and oxygen vacancy mediated Ti3+ states. As the calcination temperature and calcination time increases these oxygen vacancies and hence Ti3+ concentrations reduce in the sample. The temperature dependent magnetization curves suggest unexpected magnetic ordering, which may be due to the presence of unpaired electron at the t2g state (d1) of nearest-neighbor Ti atoms. In magnetization vs magnetic field isotherms, the regular decrease of saturation moment value with increasing calcination temperature and calcination time, can be discussed considering the amount of oxygen deficiency induced Ti3+ concentrations, present in the sample.

Calcined Mg-Fe layered double hydroxide as an absorber for the removal of methyl orange

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peng, Chao; State Key Laboratory of Silicate Materials for Architectures, Wuhan University of Technology, Wuhan 430070; Dai, Jing

2015-05-15

In this work, methyl orange (MO) was effectively removed from aqueous solution with the calcined product of hydrothermal synthesized Mg/Fe layered double hydroxide (Mg/Fe-LDH). The structure, composition, morphology and textural properties of the Mg/Fe-LDH before and after adsorption were characterized by X-ray diffraction, Fourier transformation infrared spectroscopy, transmission electron microscopy, nitrogen adsorption apparatus and X-ray photoelectron spectroscopy. It was confirmed that MO had been absorbed by calcined Mg/Fe-LDH which had strong interactions with MO. The adsorption of MO onto the Mg/Fe-LDH was systematically investigated by batch tests. The adsorption capacity of the Mg/Fe-LDH toward MO was found to be 194.9more » mg • g{sup −1}. Adsorption kinetics and isotherm studies revealed that the adsorption of MO onto Mg/Fe-LDH was a spontaneous and endothermic process. These results indicate that Mg/Fe-LDH is a promising material for the removal of MO.« less

Transesterification of edible, non-edible and used cooking oils for biodiesel production using calcined layered double hydroxides as reusable base catalysts.

PubMed

Sankaranarayanan, Sivashunmugam; Antonyraj, Churchil A; Kannan, S

2012-04-01

Fatty acid methyl esters (FAME) were produced from edible, non-edible and used cooking oils with different fatty acid contents by transesterification with methanol using calcined layered double hydroxides (LDHs) as solid base catalysts. Among the catalysts, calcined CaAl2-LDH (hydrocalumite) showed the highest activity with >90% yield of FAME using low methanol:oil molar ratio (<6:1) at 65 °C in 5 h. The activity of the catalyst was attributed to its high basicity as supported by Hammett studies and CO(2)-TPD measurements. The catalyst was successfully reused in up to four cycles. Some of the properties such as density, viscosity, neutralization number and glycerol content of the obtained biodiesel matched well with the standard DIN values. It is concluded that a scalable heterogeneously catalyzed process for production of biodiesel in high yields from a wide variety of triglyceride oils including used oils is possible using optimized conditions. Copyright © 2012 Elsevier Ltd. All rights reserved.

Experimental study on the effect of calcination on the volcanic ash activity of diatomite

NASA Astrophysics Data System (ADS)

Xiao, Liguang; Pang, Bo

2017-09-01

The volcanic ash activity of diatomite was studied under the conditions of aerobic calcination and vacuum calcination by the combined water rate method, it was characterized by XRD, BET and SEM. The results showed that the volcanic ash activity of diatomite under vacuum conditions was higher than that of aerobic calcination, 600°C vacuum calcination 2h, the combined water rate of diatomite-Ca(OH)2-H2O system was increased from 6.24% to 71.43%, the volcanic ash activity reached the maximum value, the specific surface

Cavitational synthesis of nanostructured inorganic materials for enhanced heterogeneous catalysis

NASA Astrophysics Data System (ADS)

Krausz, Ivo Michael

The synthesis of nanostructured inorganic materials by hydrodynamic cavitation processing was investigated. The goal of this work was to develop a general synthesis technique for nanostructured materials with a control over crystallite size in the 1--20 nm range. Materials with crystallite sizes in this range have shown enhanced catalytic activity compared to materials with larger crystallite sizes. Several supported and unsupported inorganic materials were studied to understand the effects of cavitation on crystallite size. Cavitation processing of calcium fluoride resulted in more spherical particles, attached to one another by melted necks. This work produced the first evidence of shock wave heating of nanostructured materials by hydrodynamic cavitation processing. Hydrodynamic cavitation synthesis of various catalytic support materials indicated that their phase composition and purity could be controlled by adjustment of the processing parameters. Zirconia/alumina supports synthesized using hydro-dynamic cavitation and calcined to 1368 K retained a high purity cubic zirconia phase, whereas classically prepared samples showed a phase transformation to monoclinic zirconia. Similarly, the synthesis of alumina resulted in materials with varying Bohmite and Bayerite contents as a function of the process parameters. High temperature calcination resulted in stable alumina supports with varying amounts of delta-, and theta-alumina. Synthesis studies of palladium and silver showed modest variations in crystallite size as a function of cavitation process parameters. Calcination resulted in larger grain materials, indicating a disappearance of intergrain boundaries. Based on these results, a new synthesis method was studied involving controlled agglomeration of small silver crystallites by hydrodynamic cavitation processing, followed by deposition on alumina. The optimal pH, concentration, and processing time for controlling the silver crystallite size in the cavitation equipment were determined using a statistical design of experiments approach. Three series of alumina supported silver catalysts were prepared, with silver weight loadings of 1%, 2%, and 5%. Variation of cavitation processing time between 1--64 min allowed the systematic control of silver crystallite size in the range of 3--19 nm. The preferred oxidation of CO in hydrogen (PROX) was chosen as a catalytic test reaction, because of its increasing importance for fuel cell applications. It was found that the catalytic activity was significantly increased for silver crystallite sizes below 5 nm. This work is the first experimental evidence of independent crystallite size control by hydrodynamic cavitation for alumina supported silver catalysts. The synthesis method involving controlled agglomeration and calcination is a general synthesis procedure that can be used to synthesize a wide range of novel catalysts and advanced materials.

High saturation magnetization of γ-Fe2O3 nano-particles by a facile one-step synthesis approach

PubMed Central

Cao, Derang; Li, Hao; Pan, Lining; Li, Jianan; Wang, Xicheng; Jing, Panpan; Cheng, Xiaohong; Wang, Wenjie; Wang, Jianbo; Liu, Qingfang

2016-01-01

We have demonstrated the synthesis of γ-Fe2O3 nano-particles through a facile and novel calcination process in the air. There is no pH regulation, gas atmosphere, additive, centrifugation or other complicated procedures during the preparing process. A detailed formation process of the nano-particles is proposed, and DMF as a polar solvent may slower the reaction process of calcination. The structures, morphologies, and magnetic properties of γ-Fe2O3 nano-particles were investigated systematically, and the pure γ-Fe2O3 nano-particles obtained at 200 °C display uniform morphology good magnetic property. The saturation magnetization of obtained pure γ-Fe2O3 is about 74 emu/g, which is comparable with bulk material (76 emu/g) and larger than other results. In addition, the photocatalytic activity for degradation of methylene blue is also studied, which shows proper photocatalytic activity. PMID:27581732

Using vacuum pyrolysis and mechanical processing for recycling waste printed circuit boards.

PubMed

Long, Laishou; Sun, Shuiyu; Zhong, Sheng; Dai, Wencan; Liu, Jingyong; Song, Weifeng

2010-05-15

The constant growth in generation of waste printed circuit boards (WPCB) poses a huge disposal problem because they consist of a heterogeneous mixture of organic and metallic chemicals as well as glass fiber. Also the presence of heavy metals, such as Pb and Cd turns this scrap into hazardous waste. Therefore, recycling of WPCB is an important subject not only from the recovery of valuable materials but also from the treatment of waste. The aim of this study was to present a recycling process without negative impact to the environment as an alternative for recycling WPCB. In this work, a process technology containing vacuum pyrolysis and mechanical processing was employed to recycle WPCB. At the first stage of this work, the WPCB was pyrolyzed under vacuum in a self-made batch pilot-scale fixed bed reactor to recycle organic resins contained in the WPCB. By vacuum pyrolysis the organic matter was decomposed to gases and liquids which could be used as fuels or chemical material resources, however, the inorganic WPCB matter was left unaltered as solid residues. At the second stage, the residues obtained at the first stage were investigated to separate and recover the copper through mechanical processing such as crushing, screening, and gravity separation. The copper grade of 99.50% with recovery of 99.86% based on the whole WPCB was obtained. And the glass fiber could be obtained by calcinations in a muffle furnace at 600 degrees C for 10 min. This study had demonstrated the feasibility of vacuum pyrolysis and mechanical processing for recycling WPCB. Copyright (c) 2009 Elsevier B.V. All rights reserved.

Hepa filter dissolution process

DOEpatents

Brewer, Ken N.; Murphy, James A.

1994-01-01

A process for dissolution of spent high efficiency particulate air (HEPA) filters and then combining the complexed filter solution with other radioactive wastes prior to calcining the mixed and blended waste feed. The process is an alternate to a prior method of acid leaching the spent filters which is an inefficient method of treating spent HEPA filters for disposal.

Is there lattice contraction in multicomponent metal oxides? Case study for GdVO4:Eu3+ nanoparticles

NASA Astrophysics Data System (ADS)

Yang, Liusai; Li, Liping; Zhao, Minglei; Fu, Chaochao; Li, Guangshe

2013-08-01

Metal oxide nanomaterials have been found to have great potential for diverse applications due to their unique relationships between structure and properties. Lattice expansion as particle size reduces was previously considered to be general for metal oxide nanomaterials. It is now a great challenge to see if lattice contraction could be induced by the size effect for metal oxide nanomaterials. ABO4 metal oxides (e.g., CaWO4, GdVO4, and CdWO4) are some of the most important functional materials with many applications, while such oxides at the nanoscale are never reported to show a lattice contraction. This work presents a first report on the variation from lattice expansion to lattice contraction by tuning the microstructures of GdVO4:Eu3+ nanocrystals. A hydrothermal method was adopted to synthesize GdVO4:Eu3+ nanocrystals, and then these nanoparticles were calcined at 600 ° C in air. It is found that particle size reduction led to a lattice contraction for the calcined samples, which is in contrast to the lattice expansion observed for the hydrothermally synthesized counterparts or many other metal oxide nanomaterials. In addition, the lattice symmetry of the calcined samples remained almost a constant. The results indicate that the negative surface stress was eliminated by calcination treatment, leading to a homogeneous compression process in the lattice structure of the calcined GdVO4:Eu3+ nanocrystals. Furthermore, Eu3+ was taken as a structural probe and a luminescence center to study the local environments pertinent to these structural changes and to optimize the photoluminescence performance.

Application of atmospheric-pressure plasma jet processed carbon nanotubes to liquid and quasi-solid-state gel electrolyte supercapacitors

NASA Astrophysics Data System (ADS)

Kuok, Fei-Hong; Kan, Ken-Yuan; Yu, Ing-Song; Chen, Chieh-Wen; Hsu, Cheng-Che; Cheng, I.-Chun; Chen, Jian-Zhang

2017-12-01

We use a dc-pulse nitrogen atmospheric-pressure plasma jet (APPJ) to calcine carbon nanotubes (CNTs) pastes that are screen-printed on carbon cloth. 30-s APPJ treatment can efficiently oxidize and vaporize the organic binders, thereby forming porous structures. As indicated by X-ray photoelectron spectroscopy (XPS) and electron probe microanalysis (EPMA), the oxygen content decreases after APPJ treatment owing to the oxidation and vaporization of ethyl cellulose, terpineol, and ethanol. Nitrogen doping was introduced to the materials by the nitrogen APPJ. APPJ-calcination improves the wettability of the CNTs printed on carbon cloth, as evidenced by water contact angle measurement. Raman spectroscopy indicates that reactive species of nitrogen APPJ react violently with CNTs in only 30-s APPJ processing time and introduce defects and/or surface functional groups on CNTs. Carbon cloths with calcined CNT layers are used as electrodes for liquid and quasi-solid-state electrolyte supercapacitors. Under a cyclic voltammetry test with a 2 mV/s potential scan rate, the specific capacitance is 73.84 F/g (areal capacitance = 5.89 mF/cm2) with a 2 M KCl electrolyte and 66.47 F/g (areal capacitance = 6.10 mF/cm2) with a H2SO4/polyvinyl alcohol (PVA) gel electrolyte.

To study the effect of dopant NiO concentration and duration of calcinations on structural and optical properties of MgO-NiO nanocomposites

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kumar, Rajesh, E-mail: rkkaushik06@gmail.com; Deptt. of Physics,Vaish College of Engineering, Rohtak-124001, Haryana; Praveen,

2016-05-06

In present work Magnesium oxide (MgO) samples were doped with different concentration of Transition metal Nickel Oxide(NiO) by using Chemical co-precipitation method. The doping levels were varied from NiO (5%, 10%, 15%) and all the samples were calcined at 600°C for 4hrs and 8hrs respectively. Structural analysis of these calcined materials is carried out by X-ray diffraction (XRD) techniques which reveals that average crystalline sizes are in nano region i.e. 21.77nm-31.13 nm and tabulated in table 1. The powder of calcined samples were also characterized by using various other techniques i.e. Scanning Electron Microscopy (SEM), Fourier Transformation Infrared Spectroscopy (FTIR), UV-Visiblemore » spectroscopy, Transmission Electron Microscopy (TEM) etc. The effects of dopant concentration, calcined temperature, calcinations duration on samples were studied and also investigate the effect of varying dopant concentration on morphology and optical properties of calcined nanomaterials. From results it was observed that the crystallite size of nanocomposites increases with increases dopant concentration or increases calcinations duration. The optical band gap decreases with increases sintering time and increase with increases dopant concentrations. TEM results coincide with XRD results and show that particles are polycrystalline in nature. FTIR spectra show that for all samples particles are pure in composition and transmission rate increases with calcinations duration.« less

46 CFR 148.295 - Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above.

Code of Federal Regulations, 2013 CFR

2013-10-01

... 46 Shipping 5 2013-10-01 2013-10-01 false Petroleum coke, calcined or uncalcined, at 55 °C (131 Â... Requirements for Certain Materials § 148.295 Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above. (a) This part does not apply to shipments of petroleum coke, calcined or uncalcined, on any vessel...

46 CFR 148.295 - Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above.

Code of Federal Regulations, 2012 CFR

2012-10-01

... 46 Shipping 5 2012-10-01 2012-10-01 false Petroleum coke, calcined or uncalcined, at 55 °C (131 Â... Requirements for Certain Materials § 148.295 Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above. (a) This part does not apply to shipments of petroleum coke, calcined or uncalcined, on any vessel...

46 CFR 148.295 - Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above.

Code of Federal Regulations, 2014 CFR

2014-10-01

... 46 Shipping 5 2014-10-01 2014-10-01 false Petroleum coke, calcined or uncalcined, at 55 °C (131 Â... Requirements for Certain Materials § 148.295 Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above. (a) This part does not apply to shipments of petroleum coke, calcined or uncalcined, on any vessel...

46 CFR 148.295 - Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 46 Shipping 5 2011-10-01 2011-10-01 false Petroleum coke, calcined or uncalcined, at 55 °C (131 Â... Requirements for Certain Materials § 148.295 Petroleum coke, calcined or uncalcined, at 55 °C (131 °F) or above. (a) This part does not apply to shipments of petroleum coke, calcined or uncalcined, on any vessel...

1. CONTEXTUAL VIEW OF WASTE CALCINING FACILITY. CAMERA FACING NORTHEAST. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

1. CONTEXTUAL VIEW OF WASTE CALCINING FACILITY. CAMERA FACING NORTHEAST. ON RIGHT OF VIEW IS PART OF EARTH/GRAVEL SHIELDING FOR BIN SET. AERIAL STRUCTURE MOUNTED ON POLES IS PNEUMATIC TRANSFER SYSTEM FOR DELIVERY OF SAMPLES BEING SENT FROM NEW WASTE CALCINING FACILITY TO THE CPP REMOTE ANALYTICAL LABORATORY. INEEL PROOF NUMBER HD-17-1. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

21. CONSTRUCTION PROGRESS VIEW OF CALCINER VESSEL ON LOW BOY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

21. CONSTRUCTION PROGRESS VIEW OF CALCINER VESSEL ON LOW BOY EN ROUTE TO FACILITY. INEEL PHOTO NUMBER NRTS-60-2487. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

22. CONSTRUCTION PROGRESS PHOTO SHOWING WORKERS LOWERING CALCINER VESSEL INTO ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

22. CONSTRUCTION PROGRESS PHOTO SHOWING WORKERS LOWERING CALCINER VESSEL INTO CELL THROUGH THE HATCH. INEEL PHOTO NUMBER NRTS-60-2485. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Sol gel method for synthesis of semiconducting ferrite and the study of FTIR, DTA, SEM and CV

NASA Astrophysics Data System (ADS)

Alva, Sagir; Hua, Tang Ing; Kalmar Nizar, Umar; Wahyudi, Haris; Sundari, Rita

2018-03-01

In this study, a sol gel method using citric acid as anionic surfactant is used for synthesis of magnesium ferrite. Calcinations of magnesium ferrite at temperature (300°C, 600°C and 800°C) have been conducted after sol gel process. Characterization study of the prepared magnesium ferrite related to calcinations using Fourier transform infrared spectrometry (FTIR), Differential thermogravic analysis (DTA), and Scanning electron microscope (SEM) has been discussed. The study of Cyclic voltammetry (CV) of the prepared magnesium ferrite has been examined to assay the semiconducting behavior of magnesium ferrite in relation to its electrochemical behavior.

Stabilization of As-, Pb-, and Cu-contaminated soil using calcined oyster shells and steel slag.

PubMed

Moon, Deok Hyun; Wazne, Mahmoud; Cheong, Kyung Hoon; Chang, Yoon-Young; Baek, Kitae; Ok, Yong Sik; Park, Jeong-Hun

2015-07-01

In this study, As-, Pb-, and Cu-contaminated soil was stabilized using calcined oyster shells (COS) and steel slag (SS). The As-contaminated soil was obtained from a timber mill site where chromate copper arsenate (CCA) was used as a preservative. On the other hand, Pb- and Cu-contaminated soil was obtained from a firing range. These two soils were thoroughly mixed to represent As-, Pb-, and Cu-contaminated soil. Calcined oyster shells were obtained by treating waste oyster shells at a high temperature using the calcination process. The effectiveness of stabilization was evaluated by 1-N HCl extraction for As and 0.1-N HCl extraction for Pb and Cu. The treatment results showed that As, Pb, and Cu leachability were significantly reduced upon the combination treatment of COS and SS. The sole treatment of SS (10 wt%) did not show effective stabilization. However, the combination treatment of COS and SS showed a significant reduction in As, Pb, and Cu leachability. The best stabilization results were obtained from the combination treatment of 15 wt% COS and 10 wt% SS. The SEM-EDX results suggested that the effective stabilization of As was most probably achieved by the formation of Ca-As and Fe-As precipitates. In the case of Pb and Cu, stabilization was most probably associated with the formation of pozzolanic reaction products such as CSHs and CAHs.

Pore surface fractal analysis of palladium-alumina ceramic membrane using Frenkel-Halsey-Hill (FHH) model.

PubMed

Ahmad, A L; Mustafa, N N N

2006-09-15

The alumina ceramic membrane has been modified by the addition of palladium in order to improve the H(2) permeability and selectivity. Palladium-alumina ceramic membrane was prepared via a sol-gel method and subjected to thermal treatment in the temperature range 500-1100 degrees C. Fractal analysis from nitrogen adsorption isotherm is used to study the pore surface roughness of palladium-alumina ceramic membrane with different chemical composition (nitric acid, PVA and palladium) and calcinations process in terms of surface fractal dimension, D. Frenkel-Halsey-Hill (FHH) model was used to determine the D value of palladium-alumina membrane. Following FHH model, the D value of palladium-alumina membrane increased as the calcinations temperature increased from 500 to 700 degrees C but decreased after calcined at 900 and 1100 degrees C. With increasing palladium concentration from 0.5 g Pd/100 ml H(2)O to 2 g Pd/100 ml H(2)O, D value of membrane decreased, indicating to the smoother surface. Addition of higher amount of PVA and palladium reduced the surface fractal of the membrane due to the heterogeneous distribution of pores. However, the D value increased when nitric acid concentration was increased from 1 to 15 M. The effect of calcinations temperature, PVA ratio, palladium and acid concentration on membrane surface area, pore size and pore distribution also studied.

25. CONSTRUCTION PROGRESS AERIAL VIEW OF WASTE CALCINING FACILITY TAKEN ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

25. CONSTRUCTION PROGRESS AERIAL VIEW OF WASTE CALCINING FACILITY TAKEN WHEN STRUCTURE WAS 99 PERCENT COMPLETE. INEEL PHOTO NUMBER NRTS-60-5409. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Water-assisted crystallization of mesoporous anatase TiO2 nanospheres

NASA Astrophysics Data System (ADS)

Li, Na; Zhang, Qiao; Joo, Ji Bong; Lu, Zhenda; Dahl, Michael; Gan, Yang; Yin, Yadong

2016-04-01

We report a facile water-assisted crystallization process for the conversion of amorphous sol-gel derived TiO2 into mesoporous anatase nanostructures with a high surface area and well-controlled porosity and crystallinity. As an alternative to conventional calcination methods, this approach works under very mild conditions and is therefore much desired for broad biological, environmental and catalytic applications.We report a facile water-assisted crystallization process for the conversion of amorphous sol-gel derived TiO2 into mesoporous anatase nanostructures with a high surface area and well-controlled porosity and crystallinity. As an alternative to conventional calcination methods, this approach works under very mild conditions and is therefore much desired for broad biological, environmental and catalytic applications. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01892k

Well-crystallized mesoporous TiO2 shells for enhanced photocatalytic activity: prepared by carbon coating and silica-protected calcination.

PubMed

Zhang, Zewu; Zhou, Yuming; Zhang, Yiwei; Zhou, Shijian; Shi, Junjun; Kong, Jie; Zhang, Sicheng

2013-04-14

Mesoporous anatase-phase TiO2 hollow shells were successfully fabricated by the solvothermal and calcination process. This method involves preparation of SiO2@TiO2 core-shell colloidal templates, sequential deposition of carbon and then silica layers through solvothermal and sol-gel processes, crystallization of TiO2 by calcination and finally removal of the inner and outer silica to produce hollow anatase TiO2 shells. The prepared samples were characterized by transmission electron microscopy, X-ray diffraction, N2 adsorption-desorption isotherms and UV-vis absorption spectroscopy. The results show that a uniform carbon layer is coated on the core-shell particles through the solvothermal process. The combustion of carbon offers the space for the TiO2 to further grow into large crystal grains, and the outer silica layer serves as a barrier against the excessive growth of anatase TiO2 nanocrystals. Furthermore, the initial crystallization of TiO2 generated in the carbon coating step and the heat generated by the combustion of the carbon layer allow the crystallization of TiO2 at a relatively low temperature without changing the uniform structure. When used as photocatalysts for the oxidation decomposition of Rhodamine B in aqueous solution under UV irradiation, the hollow TiO2 shells showed enhanced catalytic activity. Moreover, the TiO2 hollow shells prepared with optimal crystallinity by this method showed a higher performance than commercial P25 TiO2.

Catalytic property of fiber media supported palladium containing alloy nanoparticles and electrospun ceramic fibers biodurability study

NASA Astrophysics Data System (ADS)

Shin, Hyeon Ung

The nanoscale of the supporting fibers may provide enhancements such as restricting the migration of metal catalyst particles. In this work, palladium nanoparticle doped alumina fibers were electrospun into template submicron fibers. These fibers were calcined at temperatures between 650°C and 1150°C to vary the crystal structures of the calcined fibers with the Pd particle size. Higher calcination temperatures led to higher reaction temperatures from 250 to about 450°C for total conversion, indicating the effective reactivity of the fiber-supported catalysts decreased with increase in calcination temperature. Pd-Au alloy nanoparticle doped titania fibers were also fabricated using an electrospinning method and assembled into a fibrous porous medium structure by a vacuum molding process. In reactor tests, the fiber media with Pd-Au alloy nanoparticle catalyst had greater reactivity in conversion of NO and CO gases than that of fiber media with Pd monometallic catalyst alone, attributed to a lower activation energy of the Pd-Au catalyst particles. In carbon monoxide oxidation reaction tests, the results showed that the performance was optimal for a catalyst of composition Pd2Au1 molar ratio that was active at 125°C, which had higher dispersion of active components and better catalytic performance compared to monometallic particle Au/TiO 2 and Pd/TiO2 fiber media. Moreover, the improved reaction activity of Pd2Au1/TiO2 fiber medium was attributed to a decreased in the activation energy. Further experiments were conducted using the electrospun ceramic fibers biodurability study. The properties of nano-sized fiber structures have attracted the attention of recent research on ceramic nanostructures as nonwoven media for applications in hazardous chemical and high temperature environments. However, health and safety concerns of micro and nano scale ceramic materials have not been fully investigated. Little is known about the physicochemical effects of the properties of small alumina fibers, including fiber sizes, surface morphologies, crystalline, phases, and surface areas with respect to submicron sized alumina fibers formed by calcination of electrospun polymeric fibers. Therefore, in this work, sub-micron sized alumina fibers were fabricated by electrospinning and calcination of a polymer template fiber. In the calcination step, different controlled temperature heating cycles were conducted to obtain fibers of different crystalline structures. Their biodurabilities were evaluated in two types of artificial lung fluids (i.e., mimicking the airway and alveolar macrophages). Though the variation in the soak temperature, their dissolution half times were not significantly affected. The solubility half-times of the alumina fibers were shortest for fibers calcined at the fastest temperature ramp rate (though soak temperature did not have an effect).

Effect of calcination temperature on phase transformation and crystallite size of copper oxide (CuO) powders

NASA Astrophysics Data System (ADS)

Ratnawulan, Fauzi, Ahmad; AE, Sukma Hayati

2017-08-01

Copper oxide powder was prepared from Copper iron from South Solok, Indonesia. The samples was dried and calcined for an hour at temperatures of 145°C, 300°C,850°C, 1000°C. Phase transformation and crystallite size of the calcined powders have been investigated as a function of calcination temperature by room-temperature X-ray diffraction (XRD). It was seen that the tenorite, CuO was successfully obtained. With increasing calcining temperature, CuO transformed from malachite Cu2(CO3)(OH)2 to tenorite phase (CuO) and crystallite size of prepared samples increased from 36 nm to 76 nm.

Conversion of Conventional Rotary Kiln Into Effective Sandy Alumina Calciner

NASA Astrophysics Data System (ADS)

Ishihara, M.; Hirano, T.; Yajima, H.

Using conventional rotary kiln for calcining sandy alumina in potlines, remakable heat-saving and capacity-improving can be achieved. 83 liters of oil per tonne of alumina (3200MJ/tonne) were required for calcining 800 m.t.p.d. of sandy alumina in the rotary kiln at Shimizu Works. The kiln is installed with two stages of flash dryers and planetary coolers, and was originally designed for calcining floury alumina at 550 m.t.p.d. This improvement in capacity and unit oil consumption was achieved mainly through shortening the flame by using a special burner and effective heat recovery. The quality of sandy alumina calcined by the kiln is good enough for potlines.

HEPA filter dissolution process

DOEpatents

Brewer, K.N.; Murphy, J.A.

1994-02-22

A process is described for dissolution of spent high efficiency particulate air (HEPA) filters and then combining the complexed filter solution with other radioactive wastes prior to calcining the mixed and blended waste feed. The process is an alternate to a prior method of acid leaching the spent filters which is an inefficient method of treating spent HEPA filters for disposal. 4 figures.

Structural and Magnetic Properties Evolution of Co-Nd Substituted M-type Hexagonal Strontium Ferrites Synthesized by Ball-Milling-Assisted Ceramic Process

NASA Astrophysics Data System (ADS)

Chen, Wen; Wu, Wenwei; Zhou, Chong; Zhou, Shifang; Li, Miaoyu; Ning, Yu

2018-03-01

M-type hexagonal Sr1- x Co x Nd x Fe12- x O19 ( x = 0, 0.08, 0.16, and 0.24) has been synthesized by ball milling, followed by calcination in air. The calcined products have been characterized by x-ray powder diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectra, and vibrating sample magnetometry. XRD and SEM analyses confirm the formation of M-type Sr hexaferrite with platelet-like morphology when Sr1- x Co x Nd x Fe12- x O19 ( x = 0, 0.08, 0.16, and 0.24) precursors are calcined at 950°C in air for 2.5 h. Lattice parameters " a" and " c" values of Sr1- x Co x Nd x Fe12- x O19 reflect a very small variation after doping of Nd3+ and Co2+ ions. Average crystallite size of Sr1- x Co x Nd x Fe12- x O19 sample, calcined at 1150°C, decreased obviously after doping of Co2+ and Nd3+ ions. This is because the bond energy of Nd3+-O2- is much larger than that of Sr2+-O2-. Magnetic characterization indicates that all the samples exhibit good magnetic properties. Substitution of Sr2+ and Fe3+ ions by Nd3+ and Co2+ ions can improve the specific saturation magnetizations and remanence of Sr1- x Co x Nd x Fe12- x O19. Sr0.84Co0.16Nd0.16Fe11.84O19, calcined at 1050°C, has the highest specific saturation magnetization value (74.75 ± 0.60 emu/g), remanence (45.15 ± 0.32 emu/g), and magnetic moment (14.34 ± 0.11 μ B); SrFe12O19, calcined at 1150°C, has the highest coercivity value (4037.01 ± 42.39 Oe). These magnetic parameters make this material a promising candidate for applications such as high-density magnetic recording and microwave absorbing materials.

[Based on Curing Age of Calcined Coal Gangue Fine Aggregate Mortar of X-Ray Diffraction and Scanning Electron Microscopy Analysis].

PubMed

Dong, Zuo-chao; Xia, Jun-wu; Duan, Xiao-mu; Cao, Ji-chang

2016-03-01

By using X-ray diffraction (XRD) and environmental scanning electron microscope (SEM) analysis method, we stud- ied the activity of coal gangue fine aggregate under different calcination temperature. In view of the activity of the highest-700 degrees C high temperature calcined coal gangue fine aggregate mortar of hydration products, microstructure and strength were discussed in this paper, and the change laws of mortar strength with curing age (3, 7, 14, 28, 60 and 90 d) growth were analyzed. Test results showed that coal gangue fine aggregate with the increase of calcination temperature, the active gradually increases. When the calcination temperature reaches 700 degrees C, the activity of coal gangue fine aggregate is the highest. When calcining temperature continues to rise, activity falls. After 700 degrees C high temperature calcined coal gangue fine aggregate has obvious ash activity, the active components of SiO2 and Al2 O3 can be with cement hydration products in a certain degree of secondary hydration reaction. Through on the top of the activity of different curing age 700 degrees C high temperature calcined coal gangue fine aggregate mortar, XRD and SEM analysis showed that with the increase of curing age, secondary hydration reaction will be more fully, and the amount of hydration products also gradually increases. Compared with the early ages of the cement mortar, the products are more stable hydration products filling in mortar microscopic pore, which can further improve the microstructure of mortar, strengthen the interface performance of the mortar. The mortar internal structure is more uniform, calcined coal gangue fine aggregate and cement mortar are more of a strong continuous whole, which increase the later strength of hardened cement mortar, 700 degrees C high temperature calcined coal gangue fine aggregate pozzolanic effect is obvious.

29. FLOOR PLAN OF WASTE CALCINATION FACILITY SHOWING MAIN ABOVEGRADE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

29. FLOOR PLAN OF WASTE CALCINATION FACILITY SHOWING MAIN ABOVE-GRADE FLOOR LEVEL. INEEL DRAWING NUMBER 200-0633-00-287-106354. FLUOR NUMBER 5775-CPP-633-A-4. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Green Synthesis of ZnO Nanoparticles by an Alginate Mediated Ion-Exchange Process and a case study for Photocatalysis of Methylene Blue Dye

NASA Astrophysics Data System (ADS)

Keong, Choo Cheng; Sunitha Vivek, Yamini; Salamatinia, Babak; Amini Horri, Bahman

2017-04-01

In this study, zinc oxide (ZnO) was prepared via extrusion-dripping method through an ion exchange mediated process using sodium alginate. The samples were synthesized at 500 °C and 600 °C to study the effect of calcination temperature. The morphology, microstructure and optical activity of the calcined ZnO nanoparticles were analyzed by TGA, FESEM and XRD. It was found that ZnO nanoparticles synthesized at 600 °C was of higher purity with high crystallinity. To enhance the photocatalytic efficiency of zinc oxide, ZnO/NCC films were synthesized at varying ZnO loading fractions of 10 wt%, 15 wt%, 20 wt% and 25 wt% and were evaluated by photodegradation of Methylene blue dye and the highest dye percentage removal is found to be 96% which is obtained at ZnO loadings of 25 wt%. The usage of ion-exchange process has shown promising results in producing ZnO of desirable characteristics.

Using multiple bed load measurements: Toward the identification of bed dilation and contraction in gravel-bed rivers

NASA Astrophysics Data System (ADS)

Marquis, G. A.; Roy, A. G.

2012-02-01

This study examines bed load transport processes in a small gravel-bed river (Béard Creek, Québec) using three complementary methods: bed elevation changes between successive floods, bed activity surveys using tags inserted into the bed, and bed load transport rates from bed load traps. The analysis of 20 flood events capable of mobilizing bed material led to the identification of divergent results among the methods. In particular, bed elevation changes were not consistent with the bed activity surveys. In many cases, bed elevation changes were significant (1 to 2 times the D50) even if the bed surface had not been activated during the flood, leading to the identification of processes of bed dilation and contraction that occurred over 10% to 40% of the bed surface. These dynamics of the river bed prevent accurate derivation of bed load transport rates from topographic changes, especially for low magnitude floods. This paper discusses the mechanisms that could explain the dilation and contraction of particles within the bed and their implications in fluvial dynamics. Bed contraction seems to be the result of the winnowing of the fine sediments under very low gravel transport. Bed dilation seems to occur on patches of the bed at the threshold of motion where various processes such as fine sediment infiltration lead to the maintenance of a larger sediment framework volume. Both processes are also influenced by flood history and the initial local bed state and in turn may have a significant impact on sediment transport and morphological changes in gravel-bed rivers.

Apparatus and process for controlling fluidized beds

DOEpatents

Rehmat, Amirali G.; Patel, Jitendra G.

1985-10-01

An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

Easily recycled Bi2O3 photocatalyst coatings prepared via ball milling followed by calcination

NASA Astrophysics Data System (ADS)

Cheng, Lijun; Hu, Xumin; Hao, Liang

2017-06-01

Bi2O3 photocatalyst coatings derived from Bi coatings were first prepared by a two-step method, namely ball milling followed by the calcination process. The as-prepared samples were characterized by XRD, SEM, XPS and UV-Vis spectra, respectively. The results showed that monoclinic Bi2O3 coatings were obtained after sintering Bi coatings at 673 or 773 K, while monoclinic and triclinic mixed phase Bi2O3 coatings were obtained at 873 or 973 K. The topographies of the samples were observably different, which varied from flower-like, irregular, polygonal to nanosized particles with the increase in calcination temperature. Photodegradation of malachite green under simulated solar irradiation for 180 min showed that the largest degradation efficiency of 86.2% was achieved over Bi2O3 photocatalyst coatings sintered at 873 K. The Bi2O3 photocatalyst coatings, encapsulated with Al2O3 ball with an average diameter around 1 mm, are quite easily recycled, which provides an alternative visible light-driven photocatalyst suitable for practical water treatment application.

Synthesis process and photocatalytic properties of BiOBr nanosheets for gaseous benzene.

PubMed

Liu, Yu; Yin, Yongquan; Jia, Xueqing; Cui, Xiangyu; Tian, Canrui; Sang, Yuanhua; Liu, Hong

2016-09-01

A series of nano-BiOBr were prepared by an effective hydrothermal method in the presence of cetyltrimethyl ammonium bromide (CTAB) and ethanol at different calcination temperatures. The as-prepared nano-BiOBr samples were characterized by measuring the specific area (S BET), UV-Vis diffuse reflectance spectrum, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD). The results show that the calcination temperature has an important impact on the morphology and microstructure of BiOBr. The nano-BiOBr calcined at 120 °C showed excellent photocatalytic degradation properties for benzene, with photocatalytic degradation rate of 75 % for benzene under UV irradiation for 90 min, and removal efficiency of benzene was significantly enhanced by using nano-BiOBr catalyst compared to UV irradiation alone. BiOBr catalyst possessed good photocatalytic activity even after three consecutive photocatalytic reaction cycles, illustrating its excellent stability. The photocatalytic degradation of benzene followed the first-order kinetics, and the good catalytic capability of nano-BiOBr catalyst can be attributed to its crystalline, hierarchical nanostructure and nanosheet thickness.

Synthesis-microstructure-performance relationship of layered transition metal oxides as cathode for rechargeable sodium batteries prepared by high-temperature calcination.

PubMed

Xie, Man; Luo, Rui; Lu, Jun; Chen, Renjie; Wu, Feng; Wang, Xiaoming; Zhan, Chun; Wu, Huiming; Albishri, Hassan M; Al-Bogami, Abdullah S; El-Hady, Deia Abd; Amine, Khalil

2014-10-08

Research on sodium batteries has made a comeback because of concern regarding the limited resources and cost of lithium for Li-ion batteries. From the standpoint of electrochemistry and economics, Mn- or Fe-based layered transition metal oxides should be the most suitable cathode candidates for affordable sodium batteries. Herein, this paper reports a novel cathode material, layered Na1+x(Fey/2Niy/2Mn1-y)1-xO2 (x = 0.1-0.5), synthesized through a facile coprecipitation process combined with subsequent calcination. For such cathode material calcined at 800 °C for 20 h, the Na/Na1+x(Fey/2Niy/2Mn1-y)1-xO2 (x = 0.4) electrode exhibited a good capacity of 99.1 mAh g(-1) (cycled at 1.5-4.0 V) and capacity retention over 87% after 50 cycles. Optimization of this material would make layered transition metal oxides a strong candidate for the Na-ion battery cathode.

3. CONTEXTUAL VIEW OF WASTE CALCINING FACILITY, CAMERA FACING NORTHEAST. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

3. CONTEXTUAL VIEW OF WASTE CALCINING FACILITY, CAMERA FACING NORTHEAST. SHOWS RELATIONSHIP BETWEEN DECONTAMINATION ROOM, ADSORBER REMOVAL HATCHES (FLAT ON GRADE), AND BRIDGE CRANE. INEEL PROOF NUMBER HD-17-2. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

31. FLOOR PLANS OF WASTE CALCINATION FACILITY. SHOWS ACCESS CORRIDOR ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

31. FLOOR PLANS OF WASTE CALCINATION FACILITY. SHOWS ACCESS CORRIDOR AT MEZZANINE AND LOWER LEVELS. INEEL DRAWING NUMBER 200-0633-00-287-106352. FLUOR NUMBER 5775-CPP-633-A-2. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Nanometric study of nickel oxide prepared by sol gel process

NASA Astrophysics Data System (ADS)

Dessai, R. Raut; Desa, J. A. E.; Sen, D.; Babu, P. D.

2018-04-01

Nickel oxide nanopowder was synthesized by sol gel method using nickel nitrate as the starting material. Nickel oxide nanoparticles with a grain size of 15-90 nm have been studied by; small angle neutron scattering; scanning electron microscopy; and vibrating sample magnetometry. A combination of Ferro and paramagnetic behaviour of the particles after calcination at 800 °C is observed while for powder calcined at 400 °C, soft magnetic character with saturation is seen. The system of nanoparticles ofNiO embedded in a silica matrix is also studied for the structural change. Weak magnetic ordering is observed in this case with the likely-hood of particles being evenly distributed in the silica.

Synthesis of nano-sized lithium cobalt oxide via a sol-gel method

NASA Astrophysics Data System (ADS)

Li, Guangfen; Zhang, Jing

2012-07-01

In this study, nano-structured LiCoO2 thin film were synthesized by coupling a sol-gel process with a spin-coating method using polyacrylic acid (PAA) as chelating agent. The optimized conditions for obtaining a better gel formulation and subsequent homogenous dense film were investigated by varying the calcination temperature, the molar mass of PAA, and the precursor's molar ratios of PAA, lithium, and cobalt ions. The gel films on the silicon substrate surfaces were deposited by multi-step spin-coating process for either increasing the density of the gel film or adjusting the quantity of PAA in the film. The gel film was calcined by an optimized two-step heating procedure in order to obtain regular nano-structured LiCoO2 materials. Both atomic force microscopy (AFM) and scanning electron microscopy (SEM) were utilized to analyze the crystalline and the morphology of the films, respectively.

Electrosprayed Cerium Oxide Nanoparticles

NASA Astrophysics Data System (ADS)

Azar, Pedram Bagherzadeh; Tavanai, Hossein; Allafchian, Ali Reza

2018-04-01

Cerium oxide nanoparticles were fabricated via the calcination of electrosprayed polyvinyl alcohol (PVA)/cerium nitrate nanoparticles. The effect of material variables of PVA/cerium nitrate electrospraying solution, i.e. viscosity, surface tension and electrical conductivity, as well as important process variables like voltage, nozzle-collector distance and feed rate on cerium oxide nanoparticle size, are investigated. Scanning electron microscopy and Fourier-transform infrared (FTIR) spectroscopy analysis have also been carried out. The results showed that electrospraying of PVA/cerium nitrate (25% w/v) was only possible with PVA concentrations in the range of 5-8% w/v. With other conditions constant, decreasing PVA concentration, decreasing feed rate, increasing nozzle-collector distance and increasing voltage decreased the size of the final cerium oxide nanoparticles. The gross average size of all cerium oxide nanoparticles obtained in this work was about 80 nm. FTIR analysis proved the formation of cerium oxide after the calcination process.

Lead acetate trihydrate precursor route to synthesize novel ultrafine lead oxide from spent lead acid battery pastes

NASA Astrophysics Data System (ADS)

Sun, Xiaojuan; Yang, Jiakuan; Zhang, Wei; Zhu, Xinfeng; Hu, Yuchen; Yang, Danni; Yuan, Xiqing; Yu, Wenhao; Dong, Jinxin; Wang, Haifeng; Li, Lei; Vasant Kumar, R.; Liang, Sha

2014-12-01

A novel green recycling process is investigated to prepare lead acetate trihydrate precursors and novel ultrafine lead oxide from spent lead acid battery pastes. The route contains the following four processes. (1) The spent lead pastes are desulphurized by (NH4)2CO3. (2) The desulphurized pastes are converted into lead acetate solution by leaching with acetic acid solution and H2O2; (3) The Pb(CH3COO)2·3H2O precursor is crystallized and purified from the lead acetate solution with the addition of glacial acetic acid; (4) The novel ultrafine lead oxide is prepared by the calcination of lead acetate trihydrate precursor in N2 or air at 320-400 °C. Both the lead acetate trihydrate and lead oxide products are characterized by TG-DTA, XRD, and SEM techniques. The calcination products are mainly α-PbO, β-PbO, and a small amount of metallic Pb. The particle size of the calcination products in air is significantly larger than that in N2. Cyclic voltammetry measurements of the novel ultrafine lead oxide products show good reversibility and cycle stability. The assembled batteries using the lead oxide products as cathode active materials show a good cyclic stability in 80 charge/discharge cycles with the depth of discharge (DOD) of 100%.

Macroscopic and microscopic observations of particle-facilitated mercury transport from New Idria and Sulphur Bank mercury mine tailings

USGS Publications Warehouse

Lowry, G.V.; Shaw, S.; Kim, C.S.; Rytuba, J.J.; Brown, Gordon E.

2004-01-01

Mercury (Hg) release from inoperative Hg mines in the California Coast Range has been documented, but little is known about the release and transport mechanisms. In this study, tailings from Hg mines located in different geologic settings-New Idria (NI), a Si-carbonate Hg deposit, and Sulphur Bank (SB), a hot-spring Hg deposit-were characterized, and particle release from these wastes was studied in column experiments to (1) investigate the mechanisms of Hg release from NI and SB mine wastes, (2) determine the speciation of particle-bound Hg released from the mine wastes, and (3) determine the effect of calcinations on Hg release processes. The physical and chemical properties of tailings and the colloids released from them were determined using chemical analyses, selective chemical extractions, XRD, SEM, TEM, and X-ray absorption spectroscopy techniques. The total Hg concentration in tailings increased with decreasing particle size in NI and SB calcines (roasted ore), but reached a maximum at an intermediate particle size in the SB waste rock (unroasted ore). Hg in the tailings exists predominantly as low-solubility HgS (cinnabar and metacinnabar), with NI calcines having >50% HgS, SB calcines having >89% HgS, and SB waste rock having ???100% HgS. Leaching experiments with a high-ionic-strength solution (0.1 M NaCl) resulted in a rapid but brief release of soluble and particulate Hg. Lowering the ionic strength of the leach solution (0.005 M NaCl) resulted in the release of colloidal Hg from two of the three mine wastes studied (NI calcines and SB waste rock). Colloid-associated Hg accounts for as much as 95% of the Hg released during episodic particle release. Colloids generated from the NI calcines are produced by a breakup and release mechanism and consist of hematite, jarosite/alunite, and Al-Si gel with particle sizes of 10-200 nm. ATEM and XAFS analyses indicate that the majority (???78%) of the mercury is present in the form of HgS. SB calcines also produced HgS colloids. The colloids generated from the SB waste rock were heterogeneous and varied in composition according to the column influent composition. ATEM and XAFS results indicate that Hg is entirely in the HgS form. Data from this study identify colloidal HgS as the dominant transported form of Hg from these mine waste materials.

39. CALCINER CELL PLANS. TOGETHER WITH HAER ID33C37 ILLUSTRATES COMPLEXITY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

39. CALCINER CELL PLANS. TOGETHER WITH HAER ID-33-C-37 ILLUSTRATES COMPLEXITY OF PIPING. INEEL DRAWING NUMBER 200-0633-00-287-106445. FLUOR NUMBER 5775-CPP-633-P-50 - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

40. CALCINER CELL SECTIONS. TOGETHER WITH HAER ID33C37 ILLUSTRATES COMPLEXITY ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

40. CALCINER CELL SECTIONS. TOGETHER WITH HAER ID-33-C-37 ILLUSTRATES COMPLEXITY OF PIPING. INEEL DRAWING NUMBER 200-0633-00-287-106446. FLUOR NUMBER 5775-CPP-P-51. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

30. FLOOR PLANS OF WASTE CALCINATION FACILITY. SHOWS LEVELS ABOVE ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

30. FLOOR PLANS OF WASTE CALCINATION FACILITY. SHOWS LEVELS ABOVE GRADE AND AT LEVEL OF OPERATING CORRIDOR. INEEL DRAWING NUMBER 200-0633-00-287-106351. FLUOR NUMBER 5775-CPP-633-A-1. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Biotemplated synthesis of high specific surface area copper-doped hollow spherical titania and its photocatalytic research for degradating chlorotetracycline

NASA Astrophysics Data System (ADS)

Bu, Dan; Zhuang, Huisheng

2013-01-01

Copper-doped titania (Cu/TiO2) hollow microspheres were fabricated using the rape pollen as biotemplates via an improved sol-gel method and a followed calcinations process. In the fabricated process, a titanium(IV)-isopropoxide-based sol directly coated onto the surface of rape pollen. Subsequently, after calcinations, rape pollen was removed by high temperature and the hollow microsphere structure was retained. The average diameter of as-obtained hollow microspheres is 15-20 μm and the thickness of shell is approximately 0.6 μm. Knowing from XRD results, the main crystal phase of microspheres is anatase, coupled with rutile. The specific surface area varied between 141.80 m2/g and 172.51 m2/g. This hollow sphere photocatalysts with high specific surface area exhibited stronger absorption ability and higher photoactivity, stimulated by visible light. The degradation process of chlortetracycline (CTC) solution had been studied. The degradated results indicate that CTC could be effective degradated by fabricated hollow spherical materials. And the intermediate products formed in the photocatalytic process had been identified.

Effect of calcination temperature on formaldehyde oxidation performance of Pt/TiO2 nanofiber composite at room temperature

NASA Astrophysics Data System (ADS)

Xu, Feiyan; Le, Yao; Cheng, Bei; Jiang, Chuanjia

2017-12-01

Catalytic oxidation at room temperature over well-designed catalysts is an environmentally friendly method for the abatement of indoor formaldehyde (HCHO) pollution. Herein, nanocomposites of platinum (Pt) and titanium dioxide (TiO2) nanofibers with various phase compositions were prepared by calcining the electrospun TiO2 precursors at different temperatures and subsequently depositing Pt nanoparticles (NPs) on the TiO2 through a NaBH4-reduction process. The phase compositions and structures of Pt/TiO2 can be easily controlled by varying the calcination temperature. The Pt/TiO2 nanocomposites showed a phase-dependent activity towards the catalytic HCHO oxidation. Pt/TiO2 containing pure rutile phase showed enhanced activity with a turnover frequency (TOF) of 16.6 min-1 (for a calcination temperature of 800 °C) as compared to those containing the anatase phase or mixed phases. Density functional theory calculation shows that TiO2 nanofibers with pure rutile phase have stronger adsorption ability to Pt atoms than anatase phase, which favors the reduction of Pt over rutile phase TiO2, leading to higher contents of metallic Pt in the nanocomposite. In addition, the Pt/TiO2 with rutile phase possesses more abundant oxygen vacancies, which is conducive to the activation of adsorbed oxygen. Consequently, the Pt/rutile-TiO2 nanocomposite exhibited better catalytic activity towards HCHO oxidation at room temperature.

Effects of calcining temperature on formation of hierarchical TiO2/g-C3N4 hybrids as an effective Z-scheme heterojunction photocatalyst

NASA Astrophysics Data System (ADS)

Lu, Lianying; Wang, Guohong; Zou, Min; Wang, Juan; Li, Jun

2018-05-01

Hierarchical TiO2/g-C3N4 heterojunction photocatalysts with well-defined multiscale porous TiO2 framework are synthesized by simply calcinating tetrabutyl titanate and melamine precursors. The samples have been characterized by XRD, XPS, SEM, TEM, FTIR, nitrogen absorption-desorption equipment and TGA. The photocatalytic activity of these samples has been investigated in photo-degradation of Rhodamine B (RhB). The results show that calcining temperature critically affects the microstructure, surface area, interface structure and catalytic properties of the prepared samples. At the optimal calcining temperature of 550 °C, the apparent reaction rate constant of the catalyst is 55.0 × 10-3 min-1, which is 16.2 fold of pure TiO2 (3.4 × 10-3 min-1) and 3.4 fold of pure g-C3N4 (16.4 × 10-3 min-1), respectively. The strengthened visible-light-driven photocatalytic activity is attributed to the formation of a unique Z-scheme TiO2/g-C3N4 heterojunction due to C- or N-doping at the surface of the porous TiO2 framework. This mechanism explains the observation in a series of radical trapping experiments that superoxide ions and photo-generated holes play major roles in the photo-decolorizing process while hydroxyl radicals are also involved with a minor role.

CALCINATION AND SINTERING OF SORBENTS DURING BOILER INJECTION FOR DRY SULFUR DIOXIDE CONTROL

EPA Science Inventory

The paper discusses the calcination and sintering of sorbents during boiler injection for dry sulfur dioxide (S02) control, with emphasis on calcium hydroxide--Ca(OH)2--because of its superior reactivity with S02 and its wide commercial availability. Calcination and sintering are...

Development of a SREX Flowsheet for the Separation of Strontium from Dissolved INEEL Zirconium Calcine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Law, Jack Douglas; Wood, David James; Todd, Terry Allen

1999-02-01

Laboratory experimentation has indicated that the SREX process is effective for partitioning 90 Sr from acidic radioactive waste solutions located at the Idaho Nuclear Technology and Engineering Center. These laboratory results were used to develop a flowsheet for countercurrent testing of the SREX process with dissolved pilot plant calcine. Testing was performed using 24 stages of 2-cm diameter centrifugal contactors which are installed in the Remote Analytical Laboratory hot cell. Dissolved Run #64 pilot plant calcine spiked with 85 Sr was used as feed solution for the testing. The flowsheet tested consisted of an extraction section (0.15 M 4',4'(5')-di-(tert-butylcyclohexo)-18-crown-6 andmore » 1.5 M TBP in Isopar-L.), a 1.0 M NaNO3 scrub section to remove extracted K from the SREX solvent, a 0.01 M HNO3 strip section for the removal of Sr from the SREX solvent, a 0.25 M Na2CO3 wash section to remove degradation products from the solvent, and a 0.1 M HNO3 rinse section. The behavior of 85 Sr, Na, K, Al, B, Ca, Cr, Fe, Ni, and Zr was evaluated. The described flowsheet successfully extracted 85 Sr from the dissolved pilot plant calcine with a removal efficiency of 99.6%. Distribution coefficients for 85 Sr ranged from 3.6 to 4.5 in the extraction section. With these distribution coefficients a removal efficiency of approximately >99.99% was expected. It was determined that the lower than expected removal efficiency can be attributed to a stage efficiency of only 60% in the extraction section. Extracted K was effectively scrubbed from the SREX solvent with the 1.0 M NaNO3 resulting in only 6.4% of the K in the HLW strip product. Sodium was not extracted from the dissolved calcine by the SREX solvent; however, the use of a 1.0 M NaNO3 scrub solution resulted in a Na concentration of 70 mg/L (12.3% of the feed concentration) in the HLW strip product. Al, B, Ca, Cr, Fe, Ni, and Zr were determined to be essentially inextractable.« less

Development of a SREX flowsheet for the separation of strontium from dissolved INEEL zirconium calcine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Law, J.D.; Wood, D.J.; Todd, T.A.

1999-01-01

Laboratory experimentation has indicated that the SREX process is effective for partitioning {sup 90}Sr from acidic radioactive waste solutions located at the Idaho Nuclear Technology and Engineering Center. These laboratory results were used to develop a flowsheet for countercurrent testing of the SREX process with dissolved pilot plant calcine. Testing was performed using 24 stages of 2-cm diameter centrifugal contactors which are installed in the Remote Analytical Laboratory hot cell. Dissolved Run No.64 pilot plant calcine spiked with {sup 85}Sr was used as feed solution for the testing. The flowsheet tested consisted of an extraction section (0.15 M 4{prime},4{prime}(5{prime})-di-(tert-butylcyclohexo)-18-crown-6 andmore » 1.5 M TBP in Isopar-L.), a 1.0 M NaNO{sub 3} scrub section to remove extracted K from the SREX solvent, a 0.01 M HNO{sub 3} strip section for the removal of Sr from the SREX solvent, a 0.25 M Na2CO{sub 3} wash section to remove degradation products from the solvent, and a 0.1 M HNO{sub 3} rinse section. The behavior of {sup 85}Sr, Na, K, Al, B, Ca, Cr, Fe, Ni, and Zr was evaluated. The described flowsheet successfully extracted {sup 85}Sr from the dissolved pilot plant calcine with a removal efficiency of 99.6%. Distribution coefficients for {sup 85}Sr ranged from 3.6 to 4.5 in the extraction section. With these distribution coefficients a removal efficiency of approximately >99.99% was expected. It was determined that the lower than expected removal efficiency can be attributed to a stage efficiency of only 60% in the extraction section. Extracted K was effectively scrubbed from the SREX solvent with the 1.0 M NaNO{sub 3} resulting in only 6.4% of the K in the HLW strip product. Sodium was not extracted from the dissolved calcine by the SREX solvent; however, the use of a 1.0 M NaNO{sub 3} scrub solution resulted in a Na concentration of 70 mg/L (12.3% of the feed concentration) in the HLW strip product. Al, B, Ca, Cr, Fe, Ni, and Zr were determined to be essentially inextractable.« less

XANES analysis of dried and calcined bones.

PubMed

Rajendran, Jayapradhi; Gialanella, Stefano; Aswath, Pranesh B

2013-10-01

The structure of dried and calcined bones from chicken, bovine, deer, pig, sheep and chamois was examined using X-ray Absorption Near Edge Structure (XANES) spectroscopy. The oxygen K-edge absorption edge indicates that the surface of dried bone has a larger proportion of carbonate than the interior that is made up of phosphates. The phosphorus L and K edge clearly indicate that pyrophosphates, α-tricalcium phosphate (α-TCP) and hydrogen phosphates of Ca do not exist in either the dried bone or calcined bone and phosphorus exists as either β-tricalcium phosphate (β-TCP) or hydroxyapatite, both in the dried and calcined conditions. The Ca K-edge analysis indicates that β-TCP is the likely form of phosphate in both the dried and calcined conditions. Copyright © 2013 Elsevier B.V. All rights reserved.

The calcination temperature dependence of microstructural, vibrational spectra and magnetic properties of nanocrystalline Mn0.5Zn0.5Fe2O4

NASA Astrophysics Data System (ADS)

Indrayana, I. P. T.; Siregar, N.; Suharyadi, E.; Kato, T.; Iwata, S.

2016-11-01

Effect of calcination temperature on microstructural, vibrational, and magnetic properties of Mn0.5Zn0.5Fe2O4 nanoparticles have been successfully investigated. The nanoparticles were synthesized via coprecipitation method and calcined at different temperatures varying from 400, 600, 800, and 1000°C. The X-ray diffraction (XRD) pattern confirmed the formation of cubic spinel structure Mn0.5Zn0.5Fe2O4 with crystallite size ranging from 18.3 nm to 24.8 nm. The TEM micrograph showed the morphology of nanoparticles change from nearly spherical to cubic form after calcination. The FTIR spectra confirmed the existence of vibrations at 416.6 cm-1 - 455.2 cm-1 and 555.5 cm-1 -578.6 cm-1 which corresponds to the intrinsic stretching vibration of metal-oxygen at octahedral and tetrahedral sites, respectively. The maximum specific magnetization and coercivity increase with increasing calcination temperature. The maximum specific magnetization value of 54.7emu/gram was obtained for sample calcined at 1000°C. The results showed that calcination treatment will facilitate the tunability of microstructural and magnetic properties of nanoparticles for expanding the field of application.

Effect of thermal treatment on the nano-structure and phase transformation of metakaolin-based geopolymers.

PubMed

Kim, Yongsung; Kang, Seunggu

2014-11-01

Enhancement of the mechanical strength of metakaolin-based geopolymers activated with NaOH was attempted by calcining metakaolin at a higher temperature than that commonly reported. Increasing the calcination temperature from 750 degrees C to 1150 degrees C promoted the recrystallization of mullite. Two type of zeolite of sodium aluminum silicate hydrates were found in the geopolymers made of metakaolin calcined at 750 degrees C-1050 degrees C. The h-zeolite [Na6(AlSiO4)6 x H2O] was not found in the geopolymer made of metakaolin calcined above 900 degrees C, while Z-zeolite [Na2O x Al2O3 x SiO2 x H2O] remained in specimens calcined at up to 1050 degrees C, All zeolite disappeared above 1150 degrees C. The pozzolanic reaction generates very small particles of 10-30 nm on the surface of metakaolin grains of 0.2-0.6 μm, rendering the matrix denser by binding the grains. The maximum compressive strength was revealed with the geopolymer made of metakaolin calcined at 1050 degrees C. The reason for the increased strength of the geopolymer obtained using higher calcination temperature is thought to be the combined effects of matrix hardening by geopolymeric reaction and reinforcement by mullite crystal phases.

Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas

DOEpatents

Siriwardane, R.V.

1999-02-02

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form, usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas

DOEpatents

Siriwardane, R.V.

1997-12-30

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Subcarbonyl species of molybdenum hexacarbonyl supported on silica: A DRIFT study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kurhinen, M.; Venaelaeinen, T.; Pakkanen, T.A.

1994-10-06

Subspecies of partially decarbonylated molybdenum hexacarbonyl supported on silica were studied by diffuse reflectance IR spectroscopy. Mo(CO)[sub 6]/SiO[sub 2] was prepared in a fluidized bed reactor by vapor-phase adsorption of molybdenum hexacarbonyl under nitrogen flow. Decarbonylation begins when Mo(CO)[sub 6] has adsorbed onto the silica. Dehydroxylation of the support during calcination facilitates the formation of subspecies of Mo(CO)[sub 6]. The activation energy needed for bond formation between a transition metal and silica and for decarbonylation is lower than the desorption energy of physisorbed Mo(CO)[sub 6], and this was seen in the IR spectra as a disappearance of bands due tomore » subspecies. When the supported Mo(CO)[sub 6] was reheated the physisorption bands were the last to disappear from the IR spectra. 37 refs., 6 figs., 2 tabs.« less

Durable regenerable sorbent pellets for removal of hydrogen sulfide from coal gas

DOEpatents

Siriwardane, Ranjani V.

1997-01-01

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Durable regenerable sorbent pellets for removal of hydrogen sulfide coal gas

DOEpatents

Siriwardane, Ranjani V.

1999-01-01

Pellets for removing hydrogen sulfide from a coal gasification stream at an elevated temperature are prepared in durable form, usable over repeated cycles of absorption and regeneration. The pellets include a material reactive with hydrogen sulfide, in particular zinc oxide, a binder, and an inert material, in particular calcium sulfate (drierite), having a particle size substantially larger than other components of the pellets. A second inert material and a promoter may also be included. Preparation of the pellets may be carried out by dry, solid-state mixing of components, moistening the mixture, and agglomerating it into pellets, followed by drying and calcining. Pellet size is selected, depending on the type of reaction bed for which the pellets are intended. The use of inert material with a large particle size provides a stable pellet structure with increased porosity, enabling effective gas contact and prolonged mechanical durability.

Synthesis of porous sheet-like Co{sub 3}O{sub 4} microstructure by precipitation method and its potential applications in the thermal decomposition of ammonium perchlorate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lu Shanshan; Jing Xiaoyan; Liu Jingyuan

2013-01-15

Porous sheet-like cobalt oxide (Co{sub 3}O{sub 4}) were successfully synthesized by precipitation method combined with calcination of cobalt hydroxide precursors. The structure, morphology and porosity properties of the products were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and nitrogen adsorption-desorption measurement. The as-prepared sheet-like microstructures were approximately 2-3 {mu}m in average diameter, and the morphology of the cobalt hydroxide precursors was retained after the calcination process. However, it appeared a large number of uniform pores in the sheets after calcination. In order to calculate the potential catalytic activity, the thermal decomposition of ammoniummore » perchlorate (AP) has been analyzed, in which cobalt oxide played a role of an additive and the porous sheet-like Co{sub 3}O{sub 4} microstructures exhibited high catalytic performance and considerable decrease in the thermal decomposition temperature of AP. Moreover, a formation mechanism for the sheet-like microstructures has been discussed. - Graphical abstract: Porous sheet-like Co{sub 3}O{sub 4} were synthesized by facile precipitation method combined with calcination of {beta}-Co(OH){sub 2} precursors. Thermogravimetric-differential scanning calorimetric analysis indicates potential catalytic activity in the thermal decomposition of ammonium perchlorate. Highlights: Black-Right-Pointing-Pointer Synthesis of sheet-like {beta}-Co(OH){sub 2} precursors by precipitation method. Black-Right-Pointing-Pointer Porous sheet-like Co{sub 3}O{sub 4} were obtained by calcining {beta}-Co(OH){sub 2} precursors. Black-Right-Pointing-Pointer The possible formation mechanism of porous sheet-like Co{sub 3}O{sub 4} has been discussed. Black-Right-Pointing-Pointer Porous sheet-like Co{sub 3}O{sub 4} decrease the thermal decomposition temperature of ammonium perchlorate.« less

Agarose encapsulated mesoporous carbonated hydroxyapatite nanocomposites powder for drug delivery.

PubMed

Kolanthai, Elayaraja; Abinaya Sindu, P; Thanigai Arul, K; Sarath Chandra, V; Manikandan, E; Narayana Kalkura, S

2017-01-01

The powder composites are predominantly used for filling of voids in bone and as drug delivery carrier to prevent the infection or inflammatory reaction in the damaged tissues. The objective of this work was to study the synthesis of agarose encapsulation on carbonated hydroxyapatite powder and their biological and drug delivery properties. Mesoporous, nanosized carbonated hydroxyapatite/agarose (CHAp/agarose) powder composites were prepared by solvothermal method and subsequently calcined to study the physico-chemical changes, if it subjected to thermal exposure. The phase of the as-synthesized powder was CHAp/agarose whereas the calcinated samples were non-stoichiometric HAp. The CHAp/agarose nanorods were of length 10-80nm and width 40-190nm for the samples synthesized at temperatures 120°C (ST120) and 150°C (ST150). The calcination process produced spheres (10-50nm) and rods with reduced size (40-120nm length and 20-30nm width). Composites were partially dissolved in SBF solution followed by exhibited better bioactivity than non-stoichiometric HAp confirmed by gravimetric method. Hemo and biocompatibility remained unaffected by presence of agarose or carbonate in the HAp. Specific surface area of the composites was high and exhibited an enhanced amoxicillin and 5-fluorouracil release than the calcined samples. The composites demonstrated a strong antimicrobial activity against E. coli, S. aureus and S. epidermidis. The ST120 showed prolonged drug (AMX and 5-Fcil) release and antimicrobial efficacy than ST150 and calcined samples. This technique would be simple and rapid for composites preparation, to produce high quality crystalline, resorbable, mesoporous and bioactive nanocomposite (CHAp/agarose) powders. This work provides new insight into the role of agarose coated on bioceramics by solvothermal technique and suggests that CHAp/agarose composites powders are promising materials for filling of void in bone and drug delivery applications. Copyright © 2016 Elsevier B.V. All rights reserved.

32. SECTIONS AA, BB, CC, DD, AND EE WASTE CALCINATION ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

32. SECTIONS A-A, B-B, C-C, D-D, AND E-E WASTE CALCINATION FACILITY SHOWING RELATIONSHIPS OF DIFFERENT FLOOR LEVELS TO ONE ANOTHER. INEEL DRAWING NUMBER 200-0633-00-287-106353. FLUOR NUMBER 5775-CPP-633-A-3. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

40 CFR 98.213 - Calculating GHG emissions.

Code of Federal Regulations, 2010 CFR

2010-07-01

... calcination fractions with Equation U-1 of this section. ER30OC09.077 Where: ECO2 = Annual CO2 mass emissions... ton carbonate consumed. Fi = Fraction calcination achieved for each particular carbonate type i (decimal fraction). As an alternative to measuring the calcination fraction, a value of 1.0 can be used. n...

Effect of calcination temperatures on microstructures and photocatalytic activity of tungsten trioxide hollow microspheres.

PubMed

Yu, Jiaguo; Qi, Lifang; Cheng, Bei; Zhao, Xiufeng

2008-12-30

Tungsten trioxide hollow microspheres were prepared by immersing SrWO4 microspheres in a concentrated HNO3 solution, and then calcined at different temperatures. The prepared tungsten oxide samples were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, Fourier transform infrared spectra, differential thermal analysis-thermogravimetry, UV-visible spectrophotometry, scanning electron microscopy, N2 adsorption/desorption measurements. The photocatalytic activity of the samples was evaluated by photocatalytic decolorization of rhodamine B aqueous solution under visible-light irradiation. It was found that with increasing calcination temperatures, the average crystallite size and average pore size increased, on the contrary, Brunauer-Emmett-Teller-specific surface areas decreased. However, pore volume and porosity increased firstly, and then decreased. Increasing calcination temperatures resulted in the changes of surface morphology of hollow microspheres. The un-calcined and 300 degrees C-calcined samples showed higher photocatalytic activity than other samples. At 400 degrees C, the photocatalytic activity decreased greatly due to the decrease of specific surface areas. At 500 degrees C, the photocatalytic activity of the samples increased again due to the junction effect of two phases.

Removal of Dissolved Silica using Calcinated Hydrotalcite in Real-life Applications.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sasan, Koroush; Brady, Patrick Vane.; Krumhansl, James L.

Water shortages are a growing global problem. Reclamation of industrial and municipal wastewater will be necessary in order to mitigate water scarcity. However, many operational challenges, such as silica scaling, prevent large scale water reuse. Previously, our team at Sandia has demonstrated the use of selective ion exchange materials, such as calcinated hydrotalcite (HTC, (Mg 6 Al 2 (OH) 16 (CO 3 )*4H 2 O)), for the low cost removal of silica from synthetic cooling tower water. However, it is not currently know if calcinated HTC has similar capabilities in realistic applications. The purpose of this study was to investigatemore » the ability of calcinated HTC to remove silica from real cooling tower water. This was investigated under both batch and continuous conditions, and in the presence of competing ions. It was determined that calcinated HTC behaved similarly in real and synthetic cooling tower water; the HTC is highly selective for the silica even in the presence of competing cations. Therefore, the data concludes that calcinated HTC is a viable anti-scaling pretreatment for the reuse of industrial wastewaters.« less

Passivation of pigment particles for thermal control coatings

NASA Technical Reports Server (NTRS)

Farley, E. P.; Sancier, K. M.; Morrison, S. R.

1973-01-01

Five powders were received for plasma calcining during this report period. The particle size using a fluid energy mill, and obtained pigments that could be plasma calcined. Optimum results are obtained in the plasma calcining of zinc orthotitanate when finely dispersed particles are subjected to a calculated plasma temperature of 1670 C. Increasing the plasma calcining time by using multiple passes through the plasma stabilized the pigment to vacuum UV irradiation was evidenced by the resulting ESR spectra but slightly decreased the whiteness of the pigment. The observed darkening is apparently associated with the formation of Ti(+3) color centers.

40 CFR 98.213 - Calculating GHG emissions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... emissions. You must determine CO2 process emissions from carbonate use in accordance with the procedures specified in either paragraphs (a) or (b) of this section. (a) Calculate the process emissions of CO2 using calcination fractions with Equation U-1 of this section. ER30OC09.077 Where: ECO2 = Annual CO2 mass emissions...

40 CFR 98.213 - Calculating GHG emissions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... emissions. You must determine CO2 process emissions from carbonate use in accordance with the procedures specified in either paragraphs (a) or (b) of this section. (a) Calculate the process emissions of CO2 using calcination fractions with Equation U-1 of this section. ER30OC09.077 Where: ECO2 = Annual CO2 mass emissions...

40 CFR 98.213 - Calculating GHG emissions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... emissions. You must determine CO2 process emissions from carbonate use in accordance with the procedures specified in either paragraphs (a) or (b) of this section. (a) Calculate the process emissions of CO2 using calcination fractions with Equation U-1 of this section. ER30OC09.077 Where: ECO2 = Annual CO2 mass emissions...

40 CFR 98.213 - Calculating GHG emissions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... emissions. You must determine CO2 process emissions from carbonate use in accordance with the procedures specified in either paragraphs (a) or (b) of this section. (a) Calculate the process emissions of CO2 using calcination fractions with Equation U-1 of this section. ER30OC09.077 Where: ECO2 = Annual CO2 mass emissions...

Methane adsorption capacity on graphene derived from glucose and ferric chloride

NASA Astrophysics Data System (ADS)

Ismail, M. S.; Yusof, N.; Yusop, M. Zamri; Ismail, A. F.; Nasri, N. S.; Othman, F. E. Che

2018-05-01

This study examines the methane adsorption capacity using graphene derived from glucose and ferric chloride (FeCl3). The graphene was prepared via simple method by dissolution of glucose and FeCl3 in water, vaporization of water in oven, and calcination process in quartz furnace. Graphene was successfully produced with impregnation ratio of glucose and FeCl3 at 1:1 and calcination temperature of 650 °C. The prepared graphene subsequently underwent a volumetric adsorption setup, to measure the adsorption capacity of methane (CH4). The highest CH4 adsorption capacity obtained was 6.37 mmol/g at 3.5 bar and 298 K for 40 minutes. These result shows that the prepared graphene displayed good adsorption characteristic for CH4.

Research on the Treatment of Wastewater by Waste Ceramic Adsorption

NASA Astrophysics Data System (ADS)

He, Lingfeng; Zhang, Yongli; Shi, Liang

2018-03-01

The process of preparing porous ceramic with waste porcelain powder as aggregate was researched. The affect of assimilate time on cuprum removal efficiency in wastewater containing copper was investigated. The results show the water copper removal rate increased along with the augment of assimilate time, and the assimilate time is suitable for 35 min; XRD characterizations show the porous ceramic catalyst before and after calcination in active components of X ray diffraction peak position almost had no changes, and the diffraction intensity slightly changed with calcination and absorption, and diffraction peaks became sharper, and its crystallinity was improved. Baking leads to the growth of crystal particles, and the performance of porous ceramics is stable before and after adsorption.

The effect of calcination temperature on the formation and magnetic properties of ZnMn2O4 spinel

NASA Astrophysics Data System (ADS)

Hermanto, B.; Ciswandi; Afriani, F.; Aryanto, D.; Sudiro, T.

2018-03-01

The spinel based on transition-metal oxides has a typical composition of AB2O4. In this study, the ZnMn2O4 spinel was synthesized using a powder metallurgy technique. The Zn and Mn metallic powders with an atomic ratio of 1:2 were mechanically alloyed for 3 hours in aqueous solution. The mixed powder was then calcined in a muffle furnace at elevated temperature of 400, 500 and 600 °C. The X-ray Diffractometer (XRD) was used to evaluate the formation of a ZnMn2O4 spinel structure. The magnetic properties of the sample at varying calcination temperatures were characterized by a Vibrating Sample Magnetometer (VSM). The results show that the fraction of ZnMn2O4 spinel formation increases with the increase of calcination temperature. The calcination temperature also affects the magnetic properties of the samples.

Development of high T(sub c) (greater than 110 K) Bi, Tl, and Y-based materials as superconducting circuit elements

NASA Technical Reports Server (NTRS)

Haertling, Gene H.; Grabert, Gregory; Gilmour, Phillip

1992-01-01

Experimental work has continued on the development and characterization of bulk and hot pressed powders and tapecast materials in the Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O systems. A process for producing warp-free, sintered, superconducting tapes of Bi composition Bi2Sr2Ca2Cu3O(x) with a mixed oxide process was established. This procedure required a triple calcination at 830 C for 24 hours and sintering at 845 C from 20 to 200 hours. Hot pressing the triple calcined powder at 845 C for 6 hours at 5000 psi yielded a dense material which on further heat treatment at 845 C for 24 hours exhibited a Tc of 108.2 K. A further improvement in the processing of the bismuth materials was achieved via a chemical coprecipitation process wherein the starting nitrate materials were coprecipitated with oxalic acid, thus yielding a more chemically homogeneous, more reactive powder. With the coprecipitated powders, only one calcine at 830 C for 12 hours and a final sinter at 845 C for 30 hours was sufficient to produce a bulk superconducting material with a Tc of 108.4 K. SAFIRE-type grounding links were successfully fabricated from sintered, tapecast, coprecipitated BSCCO 2223 powders. Compositional and processing investigations were continued on the Tl-based superconductors. Manganese and lithium additions and sintering temperature and time were examined to determine their influence on superconducting properties. It was found that lithium substitutions for copper enhance the transition temperatures while manganese additions produced deleterious effects on the superconducting properties. A suitable procedure for producing reproducible bulk and tapecast material of Tl composition Tl2Ba2Ca2Cu3O(x) was developed and used in fabricating uniform superconducting tapes. The highest transition temperature for Tl-based tapes was measured at 110.2 K. Thallium superconducting SAFIRE-type grounding links were fabricated from the tapes.

Synthesis of strontium hexaferrite nanoparticles prepared using co-precipitation method and microemulsion processing

NASA Astrophysics Data System (ADS)

Drmota, A.; Žnidaršič, A.; Košak, A.

2010-01-01

Strontium hexaferrite (SrFe12O19) nanoparticles have been prepared with co-precipitation in aqueous solutions and precipitation in microemulsion system water/SDS/n-butanol/cyclohexane, using iron and strontium nitrates in different molar rations as a starting materials. The mixed Sr2+, Fe3+ hydroxide precursors obtained during the reaction between corresponding metal nitrates and tetramethylammonium hydroxide (TMAH), which served as a precipitating reagent, were calcined in a wide temperature range, from 350 °C to 1000 °C in a static air atmosphere. The influence of the Sr2+/Fe3+ molar ratio and the calcination temperature to the chemistry of the product formation, its crystallite size, morphology and magnetic properties were investigated. It was found that the formation of single phase SrFe12O19 with relatively high specific magnetization (54 Am2/kg) was achieved at the Sr2+/Fe3+ molar ration of 6.4 and calcination at 800 °C for 3h with heating/cooling rate 5 °C/min. The prepared powders were characterized using X-ray diffractometry (XRD) and specific surface area measurements (BET). The specific magnetization (DSM-10, magneto-susceptometer) of the prepared samples was measured.

Operation of a 25 KWth Calcium Looping Pilot-plant with High Oxygen Concentrations in the Calciner.

PubMed

Erans, María; Jeremias, Michal; Manovic, Vasilije; Anthony, Edward J

2017-10-25

Calcium looping (CaL) is a post-combustion CO2 capture technology that is suitable for retrofitting existing power plants. The CaL process uses limestone as a cheap and readily available CO2 sorbent. While the technology has been widely studied, there are a few available options that could be applied to make it more economically viable. One of these is to increase the oxygen concentration in the calciner to reduce or eliminate the amount of recycled gas (CO2, H2O and impurities); therefore, decreasing or removing the energy necessary to heat the recycled gas stream. Moreover, there is a resulting increase in the energy input due to the change in the combustion intensity; this energy is used to enable the endothermic calcination reaction to occur in the absence of recycled flue gases. This paper presents the operation and first results of a CaL pilot plant with 100% oxygen combustion of natural gas in the calciner. The gas coming into the carbonator was a simulated flue gas from a coal-fired power plant or cement industry. Several limestone particle size distributions are also tested to further explore the effect of this parameter on the overall performance of this operating mode. The configuration of the reactor system, the operating procedures, and the results are described in detail in this paper. The reactor showed good hydrodynamic stability and stable CO2 capture, with capture efficiencies of up to 70% with a gas mixture simulating the flue gas of a coal-fired power plant.

Structural and fractal characterization of tungstophosphoric acid modified titanium dioxide photocatalyst

NASA Astrophysics Data System (ADS)

Petrović, S.; Rožić, Lj; Vuković, Z.; Grbić, B.; Radić, N.; Stojadinović, S.; Vasilić, R.

2017-04-01

This article presents the comparison of structural and fractal properties of nanocrystalline titanium dioxide (TiO2) and TiO2 modified with tungstophosphoric acid (TiO2/HPW) and their impact on the photocatalytic degradation of hazardous water pollutants. TiO2 and TiO2/HPW samples were synthesized by a combined sol-gel and hydrothermal processing. The XRD analysis of pure TiO2 samples revealed that phase composition was mainly dependent on the calcination temperature, changing from amorphous TiO2 to crystalline anatase and rutile by increasing the temperature. On the other hand, the XRD of TiO2/HPW samples calcined at temperatures above 600 °C showed crystalline peaks associated to formation of WO3 and WO2.92 crystalline domains. The N2 adsorption-desorption isotherm and pore size distribution of TiO2/HPW samples detected the existence of mesoporous characteristic with very narrow bimodal pores in the mesoporous region. The structural heterogeneity of samples was analyzed by means of pore size distribution functions, while the variation in fractal dimension were determined from the nitrogen adsorption isotherms, using the modified Frenkel-Halsey-Hill method. The results demonstrate that the approach is capable of characterizing complex textures such as those present in the TiO2 and TiO2/HPW photocatalysts. Besides, the effect of calcinations condition on photocatalytic properties of the samples was also investigated. The highest efficiency with respect to methyl orange photodecomposition was observed for TiO2/HPW photocatalysts calcined at 700 °C.

Feasibility of CO₂/SO₂ uptake enhancement of calcined limestone modified with rice husk ash during pressurized carbonation.

PubMed

Chen, Huichao; Zhao, Changsui; Ren, Qiangqiang

2012-01-01

The calcination/carbonation cycle using calcium-based sorbents appears to be a viable method for carbon dioxide (CO₂) capture from combustion gases. Recent attempts to improve the CO₂/SO₂ uptake of a calcium-based sorbent modified by using rice husk ash (RHA) in the hydration process have succeeded in enhancing its effectiveness. The optimal mole ratio of RHA to calcined limestone (M(Si/Ca)) was adjusted to 0.2. The cyclic CO₂ capture characteristics and the SO₂ uptake activity of the modified sorbent were evaluated in a calcination/pressurized carbonation reactor system. Scanning electron microscope (SEM) images and X-ray diffraction (XRD) spectrum of the sorbent were also taken to supplement the study. The results showed that the carbonation conversion was greatly increased for the sorbent with M(Si/Ca) ratio of 0.2. For this sorbent formulation the optimal operating conditions were 700-750 °C and 0.5-0.7 MPa. CO₂ absorption was not proportional to CO₂ concentration in the carbonation atmosphere, but was directly related to reaction time. The CO₂ uptake decreased in the presence of SO₂. SO₂ uptake increased, and the total calcium utilization was maintained over multiple cycles. Analysis has shown that the silicate component is evenly or well distributed, and this serves as a framework to prevent sintering, thus preserving the available microstructure for reaction. The sorbent also displayed high activity to SO₂ absorption and could be used to capture CO₂ and SO₂ simultaneously. Copyright © 2011 Elsevier Ltd. All rights reserved.

A new gel route to synthesize LiCoO{sub 2} for lithium-ion batteries

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, N.; Ge, X.W.; Chen, C.H.

2005-09-01

A new synthetic route, i.e. the radiated polymer gel (RPG) method, has been developed and demonstrated for the production of LiCoO{sub 2} powders. The process involved two processes: (1) obtaining a gel by polymerizing a mixed solution of an acrylic monomer and an aqueous solution of lithium and cobalt salts under {gamma}-ray irradiation conditions and (2) obtaining LiCoO{sub 2} powders by drying and calcining the gel. Thermogravimetric analysis (TGA), X-ray diffraction (XRD) and electron scanning microscopy (SEM) were employed to study the reaction process and the structures of the powders. Galvanostatic cell cycling, cyclic voltammetry and ac impedance spectroscopy weremore » used to evaluate the electrochemical properties of the LiCoO{sub 2} powders. It was found that a pure phase of LiCoO{sub 2} can be obtained at the calcination temperature of 800 deg. C. Both the particle size (micrometer range) and specific charge/discharge capacity of an RPG-LiCoO{sub 2} powder increase with increasing the concentration of its precursor solution.« less

Magnetic nanocomposites based on phosphorus-containing polymers—structural characterization and thermal analysis

NASA Astrophysics Data System (ADS)

Alosmanov, R. M.; Szuwarzyński, M.; Schnelle-Kreis, J.; Matuschek, G.; Magerramov, A. M.; Azizov, A. A.; Zimmermann, R.; Zapotoczny, S.

2018-04-01

Fabrication of magnetic nanocomposites containing iron oxide nanoparticles formed in situ within a phosphorus-containing polymer matrix as well as its structural characterization and its thermal degradation is reported here. Comparative structural studies of the parent polymer and nanocomposites were performed using FTIR spectroscopy, x-ray diffraction, and atomic force microscopy. The results confirmed the presence of dispersed iron oxide magnetic nanoparticles in the polymer matrix. The formed composite combines the properties of porous polymer carriers and magnetic particles enabling easy separation and reapplication of such polymeric carriers used in, for example, catalysis or environmental remediation. Studies on thermal degradation of the composites revealed that the process proceeds in three stages while a significant influence of the embedded magnetic particles on that process was observed in the first two stages. Magnetic force microscopy studies revealed that nanocomposites and its calcinated form have strong magnetic properties. The obtained results provide a comprehensive characterization of magnetic nanocomposites and the products of their calcination that are important for their possible applications as sorbents (regeneration conditions, processing temperature, disposal, etc).

Impact of support calcination and competitive adsorbate in Fe/Mo-Al2O3 catalyst for synthesis of carbon nanotubes by V-flame

NASA Astrophysics Data System (ADS)

Sun, Ya-Ping; Sun, Bao-Min; Zhai, Gang; Guo, Yong-Hong; Jia, Xiao-Wei; Kang, Zhi-Zhong

2018-05-01

Carbon nanotubes (CNTs) were synthesized via carbon monoxide decomposition with aid of various Fe/Mo-Al2O3 catalysts by V-type flame method. The influences of support calcination and competitive adsorbates on the morphology and properties of CNTs were studied. SEM, HRTEM, TPO and Raman spectroscopy were applied to investigate the morphology and microstructure of CNT products. XRD, H2-TPR were employed to characterize catalysts. The obtained results indicate that calcinated support can increase production and promote the formation of CNTs with small diameter. Utilizing citric acid as a competitive adsorbate is successful in improving the quality of CNTs. Besides, the addition of citric acid and calcinated support in catalyst enhances the catalytic growth activity. The obtained CNTs have a diameter around 4–6 nm within a narrow diameter distribution range. Raman spectrum analysis also illustrates that highly graphitized CNTs are produced on the catalyst with calcinated support and citric acid. These results suggest that support calcination and competitive adsorbate have pronounced effect on the average diameter, diameter distribution, and graphitization of CNTs, which provides a simple and effective way to tune the properties of CNTs.

Apparatus for controlling fluidized beds

DOEpatents

Rehmat, Amirali G.; Patel, Jitendra G.

1987-05-12

An apparatus and process for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance.

Synthetic process for preparation of high surface area electroactive compounds for battery applications

DOEpatents

Evenson, Carl; Mackay, Richard

2013-07-23

A process is disclosed for the preparation of electroactive cathode compounds useful in lithium-ion batteries, comprising exothermic mixing of low-cost precursors and calcination under appropriate conditions. The exothermic step may be a spontaneous flameless combustion reaction. The disclosed process can be used to prepare any lithium metal phosphate or lithium mixed metal phosphate as a high surface area single phase compound.

Assessment of the technological reliability of a hybrid constructed wetland for wastewater treatment in a mountain eco-tourist farm in Poland.

PubMed

Jucherski, Andrzej; Nastawny, Maria; Walczowski, Andrzej; Jóźwiakowski, Krzysztof; Gajewska, Magdalena

2017-06-01

The aim of the present study was to assess the technological reliability of a domestic hybrid wastewater treatment installation consisting of a classic three-chambered (volume 6 m 3 ) septic tank, a vertical flow trickling bed filled with granules of a calcinated clay material (KERAMZYT), a special wetland bed constructed on a slope, and a permeable pond used as a receiver. The test treatment plant was located at a mountain eco-tourist farm on the periphery of the spa municipality of Krynica-Zdrój, Poland. The plant's operational reliability in reducing the concentration of organic matter, measured as biochemical oxygen demand (BOD 5 ) and chemical oxygen demand (COD), was 100% when modelled by both the Weibull and the lognormal distributions. The respective reliability values for total nitrogen removal were 76.8% and 77.0%, total suspended solids - 99.5% and 92.6%, and PO 4 -P - 98.2% and 95.2%, with the differences being negligible. The installation was characterized by a very high level of technological reliability when compared with other solutions of this type. The Weibull method employed for statistical evaluation of technological reliability can also be used for comparison purposes. From the ecological perspective, the facility presented in the study has proven to be an effective tool for protecting local aquifer areas.

A new synthesis route to high surface area sol gel bioactive glass through alcohol washing

PubMed Central

M. Mukundan, Lakshmi; Nirmal, Remya; Vaikkath, Dhanesh; Nair, Prabha D.

2013-01-01

Bioactive glass is one of the widely used bone repair material due to its unique properties like osteoconductivity, osteoinductivity and biodegradability. In this study bioactive glass is prepared by the sol gel process and stabilized by a novel method that involves a solvent instead of the conventional calcinations process. This study represents the first attempt to use this method for the stabilization of bioactive glass. The bioactive glass stabilized by this ethanol washing process was characterized for its physicochemical and biomimetic property in comparison with similar composition of calcined bioactive glass. The compositional similarity of the two stabilized glass powders was confirmed by spectroscopic and thermogravimetric analysis. Other physicochemical characterizations together with the cell culture studies with L929 fibroblast cells and bone marrow mesenchymal stem cells proved that the stabilization was achieved with the retention of its inherent bioactive potential. However an increase in the surface area of the glass powder was obtained as a result of this ethanol washing process and this add up to the success of the study. Hence the present study exhibits a promising route for high surface area bioactive glass for increasing biomimicity. PMID:23512012

Use of a fluidized bed for the thermal and chemicothermal treatment of metals

NASA Astrophysics Data System (ADS)

Varygin, N. N.; Ol'shanov, E. Ya.

1971-06-01

An investigation of the heat processes in a fluidized bed shows that this unit has a high heating rate and cooling rate, and allows direct control in the process of heat treatment; chemicothermal processing is speeded up 3-5 times. Examples of experimental-industrial and industrial use show the advantages of using the fluidized bed for rapid nonoxidative heating for thermal processing and pressure processing, and also for replacing expensive salt and metal baths. The use of the fluidized bed is promising for heating temperature-sensitive aluminum and other nonferrous alloys, and for heat processing refractory metals, and alloys [45], etc. It is desirable to use the fluidized bed as the cooling medium to achieve optimum cooling with reduced stresses in components of especially complex configuration. It would be promising to use the fluidized bed for carrying out chemicothermal processing and for creating new processes (including surface saturation with rare metals), especially with the application of electrical, and possibly strong magnetic, fields.

Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed.

PubMed

Sun, Rui; Ismail, Tamer M; Ren, Xiaohan; Abd El-Salam, M

2015-05-01

In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on the combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k-ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW. Copyright © 2015 Elsevier Ltd. All rights reserved.

40 CFR 60.401 - Definitions.

Code of Federal Regulations, 2011 CFR

2011-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock Plants § 60.401 Definitions. (a) Phosphate rock plant means any plant which produces or prepares phosphate rock product by any or..., calcining, and grinding. (b) Phosphate rock feed means all material entering the process unit, including...

40 CFR 60.401 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock Plants § 60.401 Definitions. (a) Phosphate rock plant means any plant which produces or prepares phosphate rock product by any or..., calcining, and grinding. (b) Phosphate rock feed means all material entering the process unit, including...

40 CFR 60.401 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock Plants § 60.401 Definitions. (a) Phosphate rock plant means any plant which produces or prepares phosphate rock product by any or..., calcining, and grinding. (b) Phosphate rock feed means all material entering the process unit, including...

40 CFR 60.401 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-07-01

... PERFORMANCE FOR NEW STATIONARY SOURCES Standards of Performance for Phosphate Rock Plants § 60.401 Definitions. (a) Phosphate rock plant means any plant which produces or prepares phosphate rock product by any or..., calcining, and grinding. (b) Phosphate rock feed means all material entering the process unit, including...

40 CFR 98.314 - Monitoring and QA/QC requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... accounting purposes including direct measurement weighing the petroleum coke fed into your process (by belt... line dioxide using plant instruments used for accounting purposes including direct measurement weighing... used to ensure the accuracy of monthly calcined petroleum coke consumption measurements. (c) You must...

Surface modification and characterization of basalt fibers as potential reinforcement of concretes

NASA Astrophysics Data System (ADS)

Iorio, M.; Santarelli, M. L.; González-Gaitano, G.; González-Benito, J.

2018-01-01

Basalt fibers were surface treated with silane coupling agents as a method to enhance the adhesion and durability of fiber-matrix interfaces in concrete based composite materials. In particular, this work has been focused on the study of basalt fibers chemical coatings with aminosilanes and their subsequent characterization. Surface treatments were carried out after removing the original sizing applied by manufacturer and pretreating them with an activation process of surface silanol regeneration. Different samples were considered to make convenient comparisons: as received fibers (commercial), calcinated fibers (without commercial sizing), activated samples (calcinated fibers subjected to an acid process for hydroxyl regeneration), and silanized fibers with γ-aminopropiltriethoxysilane, γ-aminopropilmethyldiethoxysilane and a mixture of 50% by weight of both silanes. A deep characterization was carried out in terms of structure using X-ray diffraction, XRD, and Fourier transform infrared spectroscopy, FTIR, thermal properties by thermogravimetric analysis, TGA, coupled with single differential thermal analysis, SDTA, and morphology by scanning electron microscopy, SEM, and atomic force microscopy, AFM.

Encapsulation of ultrafine metal-oxide nanoparticles within mesopores for biomass-derived catalytic applications† †Electronic supplementary information (ESI) available: Experimental section, additional characterization and reaction results. See DOI: 10.1039/c7sc04724j

PubMed Central

Fang, Ruiqi; Tian, Panliang; Yang, Xianfeng

2018-01-01

The development of efficient encapsulation strategies has attracted intense interest for preparing highly active and stable heterogeneous metal catalysts. However, issues related to low loadings, costly precursors and complex synthesis processes restrict their potential applications. Herein, we report a novel and general strategy to encapsulate various ultrafine metal-oxides nanoparticles (NPs) into the mesoporous KIT-6. The synthesis is facile, which only involves self-assembly of a metal–organic framework (MOF) precursor in the silica mesopores and a subsequent calcination process to transform the MOF into metal-oxide NPs. After the controlled calcination, the metal-oxide NPs produced from MOF decomposition are exclusively confined and uniformly distributed in the mesopores of KIT-6 with high metal loadings. Benefitting from the encapsulation effects, as-synthesized Co@KIT-6 materials exhibit superior catalytic activity and recycling stability in biomass-derived HMF oxidation under mild reaction conditions. PMID:29675231

Preparation of a porous Sn@C nanocomposite as a high-performance anode material for lithium-ion batteries

NASA Astrophysics Data System (ADS)

Zhang, Yanjun; Jiang, Li; Wang, Chunru

2015-07-01

A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries.A porous Sn@C nanocomposite was prepared via a facile hydrothermal method combined with a simple post-calcination process, using stannous octoate as the Sn source and glucose as the C source. The as-prepared Sn@C nanocomposite exhibited excellent electrochemical behavior with a high reversible capacity, long cycle life and good rate capability when used as an anode material for lithium ion batteries. Electronic supplementary information (ESI) available: Detailed experimental procedure and additional characterization, including a Raman spectrum, TGA curve, N2 adsorption-desorption isotherm, TEM images and SEM images. See DOI: 10.1039/c5nr03093e

Synthesis of cage-like LiFePO4/C microspheres for high performance lithium ion batteries

NASA Astrophysics Data System (ADS)

Deng, Honggui; Jin, Shuangling; Zhan, Liang; Wang, Yanli; Qiao, Wenming; Ling, Licheng

2012-12-01

Cage-like LiFePO4 microspheres are synthesized by a solvothermal reaction-calcination process, using Fe(NO3)3·9H2O as iron source and ethylene glycol/water as co-solvent medium. The microsphere is the assembly of LiFePO4 nanoparticles with an open porous structure, thus the carbon coating can be easily introduced on the surface of the nanoparticles by the chemical vapor deposition of C2H4 during calcination process. When used as the cathode materials for the lithium-ion batteries, the resultant cage-like LiFePO4/C microsphere shows high capacity and good cycle stability (160 mAh g-1 at 0.1 C over 300 cycles), as well as good rate capability (120 mAh g-1 at 10 C). The desirable electrochemical performance can be attributed to high rate of ionic/electronic conduction and the high structural stability arising from the interconnected open pores, carbon-coated nanoparticles and microsized structure.

Numerical and experimental studies on effects of moisture content on combustion characteristics of simulated municipal solid wastes in a fixed bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sun, Rui, E-mail: Sunsr@hit.edu.cn; Ismail, Tamer M., E-mail: temoil@aucegypt.edu; Ren, Xiaohan

Highlights: • The effects of moisture content on the burning process of MSW are investigated. • A two-dimensional mathematical model was built to simulate the combustion process. • Temperature distributions, process rates, gas species were measured and simulated. • The The conversion ratio of C/CO and N/NO in MSW are inverse to moisture content. - Abstract: In order to reveal the features of the combustion process in the porous bed of a waste incinerator, a two-dimensional unsteady state model and experimental study were employed to investigate the combustion process in a fixed bed of municipal solid waste (MSW) on themore » combustion process in a fixed bed reactor. Conservation equations of the waste bed were implemented to describe the incineration process. The gas phase turbulence was modeled using the k–ε turbulent model and the particle phase was modeled using the kinetic theory of granular flow. The rate of moisture evaporation, devolatilization rate, and char burnout was calculated according to the waste property characters. The simulation results were then compared with experimental data for different moisture content of MSW, which shows that the incineration process of waste in the fixed bed is reasonably simulated. The simulation results of solid temperature, gas species and process rate in the bed are accordant with experimental data. Due to the high moisture content of fuel, moisture evaporation consumes a vast amount of heat, and the evaporation takes up most of the combustion time (about 2/3 of the whole combustion process). The whole bed combustion process reduces greatly as MSW moisture content increases. The experimental and simulation results provide direction for design and optimization of the fixed bed of MSW.« less

Apparatus for controlling fluidized beds

DOEpatents

Rehmat, A.G.; Patel, J.G.

1987-05-12

An apparatus and process are disclosed for control and maintenance of fluidized beds under non-steady state conditions. An ash removal conduit is provided for removing solid particulates from a fluidized bed separate from an ash discharge conduit in the lower portion of the grate supporting such a bed. The apparatus and process of this invention is particularly suitable for use in ash agglomerating fluidized beds and provides control of the fluidized bed before ash agglomeration is initiated and during upset conditions resulting in stable, sinter-free fluidized bed maintenance. 2 figs.

Integrated Mg/TiO2-ionic liquid system for deep desulfurization

NASA Astrophysics Data System (ADS)

Yin, Yee Cia; Kait, Chong Fai; Fatimah, Hayyiratul; Wilfred, Cecilia

2014-10-01

A series of Mg/TiO2 photocatalysts were prepared using wet impregnation method followed by calcination at 300, 400 and 500°C for 1 h. The photocatalysts were characterized using Thermal Gravimetric Analysis, Fourier-Transform Infrared Spectroscopy, X-Ray Diffraction, and Field Emission Scanning Electron Microscopy. The performance for deep desulfurization was investigated using model oil with 100 ppm sulfur (in the form of dibenzothiophene). The integrated system involves photocatalytic oxidation followed by ionic liquid-extraction processes. The best performing photocatalyst was 0.25wt% Mg loaded on titania calcined at 400°C (0.25Mg400), giving 98.5% conversion of dibenzothiophene to dibenzothiophene sulfone. The highest extraction efficiency of 97.8% was displayed by 1,2-diethylimidazolium diethylphosphate. The overall total sulfur removal was 96.3%.

Preparation and characterization of nanosilica from oil shale ash.

PubMed

Li, Jinhong; Qian, Tingting; Tong, Lingxin; Shen, Jie

2014-05-01

Nano-sized silica powders was prepared using oil shale ash (OSA) as starting materials. A combined process was proposed for the utilization of OSA in the production of the nanosilica, including three stages: calcination, alkaline leaching and carbon dioxide separation. Effects of the calcining temperature, sodium hydroxide concentration and holding time on the desilication ratio were investigated. The microstructure and morphologies of the nano-sized silica were characterized by X-ray diffraction, transmission electron microscopy, and Brunauer-Emmett-Teller nitrogen-gas adsorption method. The results indicated that the obtained powders with particle size of about 40 nm are homegeneously dispersed and its specific surface area is 387 m2/g. The properties of the nano-sized silica powder meet the requirements of the Chinese Chemical Industry Standard HG/T 3061-1999.

Removal of oxytetracycline from aqueous solutions by hydroxyapatite as a low-cost adsorbent

NASA Astrophysics Data System (ADS)

Harja, Maria; Ciobanu, Gabriela

2017-11-01

The present paper involved a study of the adsorption process of the oxytetracycline drug from aqueous medium by using the hydroxyapatite nanopowders as adsorbent materials. The batch adsorption experiments were performed by monitoring the solution pH, contact time, adsorbent dosage and drug solution concentration. At pH 8 and ambient temperature, high oxytetracycline removal rates of about 97.58% and 89.95% for the uncalcined and calcined nanohydroxyapatites, respectively, were obtained. The kinetic studies indicate that the oxytetracycline adsorption onto nanohydroxyapatite samples follows a pseudo-second order kinetic model. The maximum adsorption capacities of 291.32 mg/g and 278.27 mg/g for uncalcined and calcined nanohydroxyapatite samples, respectively, have been found. So, the conclusion can be drawn that the hydroxyapatite shows good adsorption ability towards oxytetracycline.

The effect of heat treatment on the performance of the Ni/(Zr-Sm oxide) catalysts for carbon dioxide methanation

NASA Astrophysics Data System (ADS)

Takano, Hiroyuki; Izumiya, Koichi; Kumagai, Naokazu; Hashimoto, Koji

2011-07-01

The active catalysts for methane formation from the gas mixture of CO 2 + 4H 2 with almost 100% methane selectivity were prepared by reduction of the oxide mixture of NiO and ZrO 2 prepared by calcination of aqueous ZrO 2 sol with Sm(NO 3) 3 and Ni(NO 3) 2. The 50 at%Ni-50 at%(Zr-Sm oxide) catalyst consisting of 50 at%Ni-50 at%(Zr + Sm) with Zr/Sm = 5 calcined at 650 or 800 °C showed the highest activity for methanation. The active catalysts were Ni supported on tetragonal ZrO 2, and the activity for methanation increased by an increase in inclusion of Sm 3+ ions substituting Zr 4+ ions in the tetragonal ZrO 2 lattice as a result of an increase in calcination temperature. However, the increase in calcination temperature decreased BET surface area, metal dispersion and hydrogen uptake due to grain growth. Thus, the optimum calcination temperature existed.

Silica-associated limited systemic sclerosis after occupational exposure to calcined diatomaceous earth.

PubMed

Moisan, Stéphanie; Rucay, Pierre; Ghali, Alaa; Penneau-Fontbonne, Dominique; Lavigne, Christian

2010-10-01

Silica-associated systemic sclerosis can occur in persons using calcined diatomaceous earth for filtration purpose. A limited systemic sclerosis was diagnosed in a 52-year-old male winegrower who had a combination of Raynaud's phenomenon, oesophageal dysfunction, sclerodactyly and telangectasia. The anti-centromere antibodies titre was 1/5000. The patient was frequently exposed to high atmospheric concentrations of calcined diatomaceous earth when performing the filtration of wines. Calcined diatomaceous earth is almost pure crystalline silica under the cristobalite form. The diagnosis of silica-associated limited systemic sclerosis after exposure to calcined diatomaceous earth was made. The patient's disease met the medical, administrative and occupational criteria given in the occupational diseases list 22 bis of the agriculture Social Security scheme and thence was presumed to be occupational in origin, without need to be proved. The diagnosis of occupational disease had been recognized by the compensation system of the agricultural health insurance. Copyright © 2010 Société française de rhumatologie. Published by Elsevier SAS. All rights reserved.

The effect of precipitation and calcination parameters on oxalate derived ThO2 pellets

NASA Astrophysics Data System (ADS)

Wangle, Tadeas; Tyrpekl, Vaclav; Cagno, Simone; Delloye, Thierry; Larcher, Olivier; Cardinaels, Thomas; Vleugels, Jozef; Verwerft, Marc

2017-11-01

Thorium oxalate is easy to prepare, but the derived oxide powders retain the platelet morphology of the primary oxalate. This negatively impacts packing and sintering. If powder milling is to be avoided, powder synthesis needs to be optimized. That is the goal of this paper, where different precipitation strategies were used and their effect on powder characteristics and pellet synthesis was investigated. Oxalates prepared by adding a thorium nitrate solution to an oxalic acid solution proved most promising. Further optimizing of the calcination temperature revealed that with increasing calcination temperature the packing density improved significantly. This came at the cost of decreased early stage sintering and a higher frequency of end-capping during compaction. The calcination temperature at which the highest final density can be reached was dependent on the sintering cycle. Furthermore, the ThO2 powders had less surface area and thus adsorbed less gases during storage when calcined at higher temperatures.

Surface structural evolution of AuAg/TiO2 catalyst in the transformation of benzyl alcohol to sodium benzoate

NASA Astrophysics Data System (ADS)

Cui, Yuanyuan; Wang, Ying; Fan, Kangnian; Dai, Wei-Lin

2013-08-01

A series of AuAg/TiO2 catalysts calcined at different temperatures were used for single-pot, solvent-free synthesis of sodium benzoate and benzoic acid through the green oxidation of benzyl alcohol. The best catalytic performance, which produced a sodium benzoate yield of up to 85%, was obtained over the AuAg/TiO2 catalyst calcined at 623 K. Systematic characterizations including BET, XRD, TEM, XPS, and UV-vis DRS and ICP were carried out to investigate the influence of calcined temperature on the structural evolution of the bimetallic AuAg/TiO2 catalysts. TEM images showed that both low (473 K) and high calcinations temperatures (973 K) resulted in larger particles. The smallest particles (8.2 nm) were obtained at 623 K. This decrease in particle size may have been induced by the re-dispersion and interaction of the bimetallic species. XRD and XPS results showed that proper calcination temperature (623 K) could promote interactions between the bimetallic particles and the TiO2 support as well as the dispersion of active bimetallic species. The higher catalytic performance of the 623 K calcined catalyst could be attributed to the smaller particle size and the synergetic interaction between nano-bimetallic gold and silver species.

The effect of calcination temperature on the microstructure and photocatalytic activity of TiO2-based composite nanotubes prepared by an in situ template dissolution method

NASA Astrophysics Data System (ADS)

Fan, Jiajie; Zhao, Li; Yu, Jiaguo; Liu, Gang

2012-09-01

TiO2-based composite nanotubes, based on an in situ template dissolution method, were one-step fabricated in a mixed aqueous solution of ammonium hexafluorotitanate and boric acid using ZnO nanorods as templates, and then the samples were calcined at different temperatures. The photocatalytic activity of the samples was evaluated by photocatalytic decoloration of Methyl Orange (MO) aqueous solution at ambient temperature under UV light. The results showed that the prepared sample possessed nanoscale tubular morphology with a wall thickness of ca. 30-50 nm, inner diameters of ca. 50-150 nm and lengths of ca. 400-2000 nm. The calcined samples exhibited excellent stabilization of the anatase phase in a wide temperature range of 300-800 °C. The un-calcined and calcined samples possessed hierarchically macro-mesoporous structures. The sample calcined at 600 °C exhibited the highest photocatalytic activity, corresponding to the maximal formation rate of \\z.rad OH on the photocatalyst. This is attributed to the improvement of anatase TiO2 crystallization, the formation of multi-phase structures including anatase, cubic Zn2TiO4, hexagonal ZnTiO3 and cubic ZnTiO3, and the presence of hierarchically macro-mesoporous structures.

Preparation, Characterization and Thermo-Chromic Properties of EVA/VO2 Laminate Films for Smart Window Applications and Energy Efficiency in Building

PubMed Central

Srirodpai, Onruthai; Wootthikanokkhan, Jatuphorn; Nawalertpanya, Saiwan; Yuwawech, Kitti; Meeyoo, Vissanu

2017-01-01

Thermochromic films based on vanadium dioxide (VO2)/ethylene vinyl acetate copolymer (EVA) composite were developed. The monoclinic VO2 particles was firstly prepared via hydrothermal and calcination processes. The effects of hydrothermal time and tungsten doping agent on crystal structure and morphology of the calcined metal oxides were reported. After that, 1 wt % of the prepared VO2 powder was mixed with EVA compound, using two different mixing processes. It was found that mechanical properties of the EVA/VO2 films prepared by the melt process were superior to those of which prepared by the solution process. On the other hand, percentage visible light transmittance of the solution casted EVA/VO2 film was greater than that of the melt processed composite film. This was related to the different gel content of EVA rubber and state of dispersion and distribution of VO2 within the polymer matrix phase. Thermochromic behaviors and heat reflectance of the EVA/VO2 film were also verified. In overall, this study demonstrated that it was possible to develop a thermochromic film using the polymer composite approach. In this regard, the mixing condition was found to be one of the most important factors affecting morphology and thermo-mechanical properties of the films. PMID:28772413

Preparation, Characterization and Thermo-Chromic Properties of EVA/VO₂ Laminate Films for Smart Window Applications and Energy Efficiency in Building.

PubMed

Srirodpai, Onruthai; Wootthikanokkhan, Jatuphorn; Nawalertpanya, Saiwan; Yuwawech, Kitti; Meeyoo, Vissanu

2017-01-11

Thermochromic films based on vanadium dioxide (VO₂)/ethylene vinyl acetate copolymer (EVA) composite were developed. The monoclinic VO₂ particles was firstly prepared via hydrothermal and calcination processes. The effects of hydrothermal time and tungsten doping agent on crystal structure and morphology of the calcined metal oxides were reported. After that, 1 wt % of the prepared VO₂ powder was mixed with EVA compound, using two different mixing processes. It was found that mechanical properties of the EVA/VO₂ films prepared by the melt process were superior to those of which prepared by the solution process. On the other hand, percentage visible light transmittance of the solution casted EVA/VO₂ film was greater than that of the melt processed composite film. This was related to the different gel content of EVA rubber and state of dispersion and distribution of VO₂ within the polymer matrix phase. Thermochromic behaviors and heat reflectance of the EVA/VO₂ film were also verified. In overall, this study demonstrated that it was possible to develop a thermochromic film using the polymer composite approach. In this regard, the mixing condition was found to be one of the most important factors affecting morphology and thermo-mechanical properties of the films.

Surface Structure and Photocatalytic Activity of Nano-TiO2 Thin Film

EPA Science Inventory

Controlled titanium dioxide (TiO2) thin films were deposited on stainless steel surfaces using flame aerosol synthetic technique, which is a one-step coating process, that doesn’t require further calcination. Solid state characterization of the coatings was conducted by different...

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

This document contains information about the research programs being conducted at the Savannah River Plant. Topics of discussion include: thermal cycling absorption process, development of new alloys, ion exchange, oxalate precipitation, calcination, environmental research, remedial action, ecological risk assessments, chemical analysis of salt cakes, natural phenomena hazards assessment, and sampling of soils and groundwater.

PROCESSING OF RADIOACTIVE WASTE

DOEpatents

Johnson, B.M. Jr.; Barton, G.B.

1961-11-14

A process for treating radioactive waste solutions prior to disposal is described. A water-soluble phosphate, borate, and/or silicate is added. The solution is sprayed with steam into a space heated from 325 to 400 deg C whereby a powder is formed. The powder is melted and calcined at from 800 to 1000 deg C. Water vapor and gaseous products are separated from the glass formed. (AEC)

Synthesis and antibacterial evaluation of calcinated Ag-doped nano-hydroxyapatite with dispersibility.

PubMed

Furuzono, Tsutomu; Motaharul, Mazumder; Kogai, Yasumichi; Azuma, Yoshinao; Sawa, Yoshiki

2015-05-01

Dispersible hydroxyapatite (HAp) nanoparticles are very useful for applying a monolayer to implantable medical devices using the nano-coating technique. To improve tolerance to infection on implanted medical devices, silver-doped HAp (Ag-HAp) nanoparticles with dispersiblity and crystallinity were synthesized, avoiding calcination-induced sintering, and evaluated for antibacterial activity. The Ca10-xAgx(PO4)6(OH)2 with x = 0 and 0.2 were prepared by wet chemical processing at 100°C. Before calcination at 700°C for 2 h, two kinds of anti-sintering agents, namely a Ca(NO3)2 (Ca salt) and a polyacrylic acid/Ca salt mixture (PAA-Ca), were used. Escherichia coli was used to evaluate the antibacterial activity of the nanopowder. When PAA-Ca was used as an anti-sintering agent in calcination to prepare the dispersible nanoparticles, strong metallic Ag peaks were observed at 38.1° and 44.3° (2θ) in the X-ray diffraction (XRD) profile. However, the Ag peak was barely observed when Ca salt was used alone as the anti-sintering agent. Thus, using Ca salt alone was more effective for preparation of dispersible Ag-HAp than PAA-Ca. The particle average size of Ag-HAp with 0.5 mol% of Ag content was found to be 325 ± 70 nm when the formation of large particleaggregations was prevented, as determined by dynamic light scattering instrument. The antibacterial activity of the Ag-HAp nanoparticles possessing 0.5 mol% against E. coli was greater than 90.0%. Dispersible and crystalline nano Ag-HAp can be obtained by using Ca salt alone as an anti-sintering agent. The nanoparticles showed antibacterial activity.

Characterization of the enhancement effect of Na2CO3 on the sulfur capture capacity of limestones.

PubMed

Laursen, Karin; Kern, Arnt A; Grace, John R; Lim, C Jim

2003-08-15

It has been known for a long time that certain additives (e.g., NaCl, CaCl2, Na2CO3, Fe2O3) can increase the sulfur dioxide capture-capacity of limestones. In a recent study we demonstrated that very small amounts of Na2CO3 can be very beneficial for producing sorbents of very high sorption capacities. This paper explores what contributes to these significant increases. Mercury porosimetry measurements of calcined limestone samples reveal a change in the pore-size from 0.04-0.2 microm in untreated samples to 2-10 microm in samples treated with Na2CO3--a pore-size more favorable for penetration of sulfur into the particles. The change in pore-size facilitates reaction with lime grains throughout the whole particle without rapid plugging of pores, avoiding premature change from a fast chemical reaction to a slow solid-state diffusion controlled process, as seen for untreated samples. Calcination in a thermogravimetric reactor showed that Na2CO3 increased the rate of calcination of CaCO3 to CaO, an effect which was slightly larger at 825 degrees C than at 900 degrees C. Peak broadening analysis of powder X-ray diffraction data of the raw, calcined, and sulfated samples revealed an unaffected calcite size (approximately 125-170 nm) but a significant increase in the crystallite size for lime (approximately 60-90 nm to approximately 250-300 nm) and less for anhydrite (approximately 125-150 nm to approximately 225-250 nm). The increase in the crystallite and pore-size of the treated limestones is attributed to an increase in ionic mobility in the crystal lattice due to formation of vacancies in the crystals when Ca is partly replaced by Na.

Feasibility of sulfate-calcined eggshells for removing pathogenic bacteria and antibiotic resistance genes from landfill leachates.

PubMed

Ye, Mao; Sun, Mingming; Chen, Xu; Feng, Yanfang; Wan, Jinzhong; Liu, Kuan; Tian, Da; Liu, Manqiang; Wu, Jun; Schwab, Arthur P; Jiang, Xin

2017-05-01

High abundance of human pathogen and antibiotic resistance genes (ARGs) in landfill leachate has become an emerging threat against human health. Therefore, sulfate- and calcination-modified eggshells as green agricultural bioresource were applied to test the feasibility of removing pathogenic bacteria and ARGs from leachate. The highest removal of Escherichia coli (E. coil) and gentamycin resistant gene (gmrA) from artificial contaminated landfill leachate was achieved by the application of eggshell with combined treatment of sulfate and calcination. The 16S and gmrA gene copies of E. coil declined significantly from 1.78E8±8.7E6 and 4.12E8±5.9E6 copies mL -1 to 1.32E7±2.6E6 and 2.69E7±7.2E6 copies mL -1 , respectively, within 24h dynamic adsorption equilibrium process (p<0.05). Moreover, according to the Langmuir kinetic model, the greatest adsorption amount (1.56×10 9 CFU E. coil per gram of modified eggshells) could be obtained at neutral pH of 7.5. The optimal adsorption eggshells were then screened to the further application in three typical landfill leachates in Nanjing, eastern China. Significant decrease in species and abundance of pathogenic bacteria and ARGs (tet, sul, erm, qnr, and ampC) indicated its great efficiency to purify landfill leachates. This study demonstrated that sulfate-calcined eggshells can be an environmentally-friendly and highly efficient bioadsorbent to the management of reducing dissemination risk of pathogen and ARGs in landfill leachate. Copyright © 2017 Elsevier Ltd. All rights reserved.

Small-scale studies of roasted ore waste reveal extreme ranges of stable mercury isotope signatures

NASA Astrophysics Data System (ADS)

Smith, Robin S.; Wiederhold, Jan G.; Jew, Adam D.; Brown, Gordon E.; Bourdon, Bernard; Kretzschmar, Ruben

2014-07-01

Active and closed Hg mines are significant sources of Hg contamination to the environment, mainly due to large volumes of mine waste material disposed of on-site. The application of Hg isotopes as source tracer from such contaminated sites requires knowledge of the Hg isotope signatures of different materials potentially released to the environment. Previous work has shown that calcine, the waste residue of the on-site ore roasting process, can exhibit distinct Hg isotope signatures compared with the primary ore. Here, we report results from a detailed small-scale study of Hg isotope variations in calcine collected from the closed New Idria Hg mine, San Benito County, CA, USA. The calcine samples exhibited different internal layering features which were investigated using optical microscopy, micro X-ray fluorescence, micro X-ray absorption spectroscopy (μ-XAS), and stable Hg isotope analysis. Significant Fe, S, and Hg concentration gradients were found across the different internal layers. Isotopic analyses revealed an extreme variation with pronounced isotopic gradients across the internal layered features. Overall, δ202Hg (±0.10‰, 2 SD) describing mass-dependent fractionation (MDF) ranged from -5.96 to 14.49‰, which is by far the largest range of δ202Hg values reported for any environmental sample. In addition, Δ199Hg (±0.06‰, 2 SD) describing mass-independent fractionation (MIF) ranged from -0.17 to 0.21‰. The μ-XAS analyses suggested that cinnabar and metacinnabar are the dominant Hg-bearing phases in the calcine. Our results demonstrate that the incomplete roasting of HgS ores in Hg mines can cause extreme mass-dependent Hg isotope fractionations at the scale of individual calcine pieces with enrichments in both light and heavy Hg isotopes relative to the primary ore signatures. This finding has important implications for the application of Hg isotopes as potential source tracers for Hg released to the environment from closed Hg mines and highlights the need for detailed source signature identification.

7. WASTE CALCINING FACILITY, LOOKING AT NORTH END OF BUILDING. ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

7. WASTE CALCINING FACILITY, LOOKING AT NORTH END OF BUILDING. CAMERA FACING SOUTH. TENT-ROOFED COVER IN RIGHT OF VIEW IS A TEMPORARY WEATHER-PROOFING SHELTER OVER THE BLOWER PIT IN CONNECTION WITH DEMOLITION PROCEDURES. SMALL BUILDING CPP-667 IN CENTER OF VIEW WAS USED FOR SUPPLEMENTARY OFFICE SPACE BY HEALTH PHYSICISTS AND OTHERS. INEEL PROOF SHEET NOT NUMBERED. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Application of CaO-Based Bed Material for Dual Fluidized Bed Steam Biomass Gasification

NASA Astrophysics Data System (ADS)

Koppatz, S.; Pfeifer, C.; Kreuzeder, A.; Soukup, G.; Hofbauer, H.

Gasification of biomass is a suitable option for decentralized energy supply based on renewable sources in the range of up to 50 MW fuel input. The paper presents the dual fluidized bed (DFB) steam gasification process, which is applied to generate high quality and nitrogen-free product gas. Essential part of the DFB process is the bed material used in the fluidized reactors, which has significant impact on the product gas quality. By the use of catalytically active bed materials the performance of the overall process is increased, since the bed material favors reactions of the steam gasification. In particular, tar reforming reactions are favored. Within the paper, the pilot plant based on the DFB process with 100kW fuel input at Vienna University of Technology, Austria is presented. Actual investigations with focus on CaO-based bed materials (limestone) as well as with natural olivine as bed material were carried out at the pilot plant. The application of CaO-based bed material shows mainly decreased tar content in the product gas in contrast to experiments with olivine as bed material. The paper presents the results of steam gasification experiments with limestone and olivine, whereby the product gas composition as well as the tar content and the tar composition are outlined.

A modified sulfate process to lunar oxygen

NASA Technical Reports Server (NTRS)

Sullivan, Thomas A.

1992-01-01

A modified sulfate process which produces oxygen from iron oxide-bearing minerals in lunar soil is under development. Reaction rates of ilmenite in varying strength sulfuric acid have been determined. Quantitative conversion of ilmenite to ferrous sulfate was observed over a range of temperatures and concentrations. Data has also been developed on the calcination of by-product sulfates. System engineering for overall operability and simplicity has begun, suggesting that a process separating the digestion and sulfate dissolution steps may offer an optimum process.

Mesoporous titanium dioxide (TiO2) with hierarchically 3D dendrimeric architectures: formation mechanism and highly enhanced photocatalytic activity.

PubMed

Li, Xiao-Yun; Chen, Li-Hua; Rooke, Joanna Claire; Deng, Zhao; Hu, Zhi-Yi; Wang, Shao-Zhuan; Wang, Li; Li, Yu; Krief, Alain; Su, Bao-Lian

2013-03-15

Mesoporous TiO(2) with a hierarchically 3D dendrimeric nanostructure comprised of nanoribbon building units has been synthesized via a spontaneous self-formation process from various titanium alkoxides. These hierarchically 3D dendrimeric architectures can be obtained by a very facile, template-free method, by simply dropping a titanium butoxide precursor into methanol solution. The novel configuration of the mesoporous TiO(2) nanostructure in nanoribbon building units yields a high surface area. The calcined samples show significantly enhanced photocatalytic activity and degradation rates owing to the mesoporosity and their improved crystallinity after calcination. Furthermore, the 3D dendrimeric architectures can be preserved after phase transformation from amorphous TiO(2) to anatase or rutile, which occurs during calcination. In addition, the spontaneous self-formation process of mesoporous TiO(2) with hierarchically 3D dendrimeric architectures from the hydrolysis and condensation reaction of titanium butoxide in methanol has been followed by in situ optical microscopy (OM), revealing the secret on the formation of hierarchically 3D dendrimeric nanostructures. Moreover, mesoporous TiO(2) nanostructures with similar hierarchically 3D dendrimeric architectures can also be obtained using other titanium alkoxides. The porosities and nanostructures of the resultant products were characterized by SEM, TEM, XRD, and N(2) adsorption-desorption measurements. The present work provides a facile and reproducible method for the synthesis of novel mesoporous TiO(2) nanoarchitectures, which in turn could herald the fabrication of more efficient photocatalysts. Copyright © 2012 Elsevier Inc. All rights reserved.

40 CFR 63.605 - Monitoring requirements.

Code of Federal Regulations, 2011 CFR

2011-07-01

... the mass flow of phosphorus-bearing feed material to the process. The monitoring system shall have an... either the mass flow of phosphorus-bearing feed material to the dryer or calciner, or the mass flow of... total mass rate in metric ton/hour of phosphorus bearing feed using a monitoring system for measuring...

40 CFR 63.605 - Monitoring requirements.

Code of Federal Regulations, 2010 CFR

2010-07-01

... the mass flow of phosphorus-bearing feed material to the process. The monitoring system shall have an... either the mass flow of phosphorus-bearing feed material to the dryer or calciner, or the mass flow of... total mass rate in metric ton/hour of phosphorus bearing feed using a monitoring system for measuring...

Eco-friendly Synthesis of Ceria Foam via Carboxymethylcellulose Gelation: Application for the Epoxidation of Chalcone

EPA Science Inventory

A simple and innovative process is described for the eco-friendly preparation of ceria foams via the carboxymethylcellulose gelation by Ce4+ cations; heat treatment of the ensuing xerogels produces ceria foams. The influence of the concentration of cerium and of the calcination t...

Process for solidifying high-level nuclear waste

DOEpatents

Ross, Wayne A.

1978-01-01

The addition of a small amount of reducing agent to a mixture of a high-level radioactive waste calcine and glass frit before the mixture is melted will produce a more homogeneous glass which is leach-resistant and suitable for long-term storage of high-level radioactive waste products.

Synthesis of Monodispersed Tantalum(V) oxide Nanospheres by an Ethylene Glycol Mediated Route

EPA Science Inventory

Tantalum(V) oxide (Ta2O5) nanospheres have been synthesized by a very simple ethylene glycol mediated route. The two-step process involves the formation of glycolate nanoparticles and their subsequent hydrolysis and calcination to generate the final Ta2O5 nanospheres. The synthes...

Development of Highly Durable and Reactive Regenerable Magnesium-Based Sorbents for CO2 Separation in Coal Gasification Process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Javad Abbasian; Armin Hassanzadeh Khayyat; Rachid B. Slimane

The specific objective of this project was to develop physically durable and chemically regenerable MgO-based sorbents that can remove carbon dioxide from raw coal gas at operating condition prevailing in IGCC processes. A total of sixty two (62) different sorbents were prepared in this project. The sorbents were prepared either by various sol-gel techniques (22 formulations) or modification of dolomite (40 formulations). The sorbents were prepared in the form of pellets and in granular forms. The solgel based sorbents had very high physical strength, relatively high surface area, and very low average pore diameter. The magnesium content of the sorbentsmore » was estimated to be 4-6 % w/w. To improve the reactivity of the sorbents toward CO{sub 2}, The sorbents were impregnated with potassium salts. The potassium content of the sorbents was about 5%. The dolomite-based sorbents were prepared by calcination of dolomite at various temperature and calcination environment (CO{sub 2} partial pressure and moisture). Potassium carbonate was added to the half-calcined dolomite through wet impregnation method. The estimated potassium content of the impregnated sorbents was in the range of 1-6% w/w. In general, the modified dolomite sorbents have significantly higher magnesium content, larger pore diameter and lower surface area, resulting in significantly higher reactivity compared to the sol-gel sorbents. The reactivities of a number of sorbents toward CO{sub 2} were determined in a Thermogravimetric Analyzer (TGA) unit. The results indicated that at the low CO{sub 2} partial pressures (i.e., 1 atm), the reactivities of the sorbents toward CO{sub 2} are very low. At elevated pressures (i.e., CO{sub 2} partial pressure of 10 bar) the maximum conversion of MgO obtained with the sol-gel based sorbents was about 5%, which corresponds to a maximum CO{sub 2} absorption capacity of less than 1%. The overall capacity of modified dolomite sorbents were at least one order of magnitude higher than those of the sol-gel based sorbents. The results of the tests conducted with various dolomite-based sorbent indicate that the reactivity of the modified dolomite sorbent increases with increasing potassium concentration, while higher calcination temperature adversely affects the sorbent reactivity. Furthermore, the results indicate that as long as the absorption temperature is well below the equilibrium temperature, the reactivity of the sorbent improves with increasing temperature (350-425 C). As the temperature approaches the equilibrium temperature, because of the significant increase in the rate of reverse (i.e., regeneration) reaction, the rate of CO{sub 2} absorption decreases. The results of cyclic tests show that the reactivity of the sorbent gradually decreases in the cyclic process. To improve long-term durability (i.e., reactivity and capacity) of the sorbent, the sorbent was periodically re-impregnated with potassium additive and calcined. The results indicate that, in general, re-treatment improves the performance of the sorbent, and that, the extent of improvement gradually decreases in the cyclic process. The presence of steam significantly enhances the sorbent reactivity and significantly decreases the rate of decline in sorbent deactivation in the cyclic process.« less

Effects of Coal Gangue on Cement Grouting Material Properties

NASA Astrophysics Data System (ADS)

Liu, J. Y.; Chen, H. X.

2018-05-01

The coal gangue is one of the most abundant industrial solid wastes and pollute source of air and water. The use of coal gangue in the production of cement grouting material comforms to the basic state policy of environment protection and the circular using of natural resources. Through coal gangue processing experiment, coal gangue cement grouting materials making test, properties detection of properties and theoretical analysis, the paper studied the effects of coal gangue on the properties of cement grouting materials. It is found that at the range of 600 to 700 °C, the fluidity and the compressive and flexural strengths of the cement grouting materials increase with the rising up of the calcination temperatures of coal gangue. The optimum calcination temperature is around 700 °C. The part substitution of cement by the calcined coal gangue in the cement grouting material will improve the mechanical properties of the cement grouting material, even thought it will decrease its fluidity. The best substitution amount of cement by coal gangue is about 30%. The fluidity and the long term strength of the ordinary silicate cement grouting material is obviously higher than that of the sulphoaluminate cement one as well as that of the silicate-sulphoaluminate complex cement one.

Characteristics of nano-sized yttria powder synthesized by a polyvinyl alcohol solution route at low temperature.

PubMed

Lee, Sang-Jin; Jung, Choong-Hwan

2012-01-01

Nano-sized yttria (Y2O3) powders were successfully synthesized at a low temperature of 400 degrees C by a simple polymer solution route. PVA polymer, as an organic carrier, contributed to an atom-scale homogeneous precursor gel and it resulted in fully crystallized, nano-sized yttria powder with high specific surface area through the low temperature calcination. In this process, the content of PVA, calcination temperature and heating time affected the microstructure and crystallization behavior of the powders. The development of crystalline phase and the final particle size were strongly dependant on the oxidation reaction from the polymer burn-out step and the PVA content. In this paper, the PVA solution technique for the fabrication of nano-sized yttria powders is introduced. The effects of PVA content and holding time on the powder morphology and powder specific surface area are also studied. The characterization of the synthesized powders is examined by using XRD, DTA/TG, SEM, TEM and nitrogen gas adsorption. The yttria powder synthesized from the PVA content of 3:1 ratio and calcined at 400 degrees C had a crystallite size of about 20 nm or less with a high surface areas of 93.95-120.76 m2 g(-1).

Properties of carbonate rocks related to SO2 reactivity

USGS Publications Warehouse

Borgwardt, R.H.; Harvey, R.D.

1972-01-01

Petrographic examination and grain size-distribution measurements were made on 11 specimens representing a broad spectrum of limestones and dolomites. The SO2 reaction kinetics of calcines prepared from each rock type were determined at 980??C. Stones of various geological types yield calcines of distinctly different physical structures that show correspondingly large differences in both rate of reaction and capacity for SO2 sorption. Pore size and particle size together determine the extent to which the interiors of individual particles react. Particles smaller than 0.01 cm with pores larger than 0.1 ?? react throughout their internal pore structure at a rate directly proportional to the BET surface. The rate decays exponentially as sulfation proceeds until the pores are filled with reaction product. The ultimate capacity of small particles is determined by the pore volume available for product accumulation, which is generally equivalent to about 50% conversion of the CaO in limestones. Variations in effectiveness of carbonate rocks for flue gas desulfurization are explained by the physical properties of their calcines, which are related to the crystal structure of the original rock. The high reaction rates achieved in the limestone injection process apparently result from the large surface area existing for short periods immediately following the dissociation of CaCO3.

Macroporous Calcium Phosphate/Chitosan Composites Prepared via Unidirectional Ice Segregation and Subsequent Freeze-Drying

PubMed Central

Aranaz, Inmaculada; Martínez-Campos, Enrique; Moreno-Vicente, Carolina; Civantos, Ana; García-Arguelles, Sara; del Monte, Francisco

2017-01-01

Calcium phosphate chitosan-based composites have gained much interest in recent years for biomedical purposes. In this paper, three-dimensional calcium phosphate chitosan-based composites with different mineral contents were produced using a green method called ice segregation induced self-assembly (ISISA). In this methodology, ice crystals were used as a template to produce porous structures from an aqueous solution of chitosan (CS) and hydroxyapatite (Hap) also containing acetic acid (pH = 4.5). For better characterization of the nature of the inorganic matter entrapped within the resulting composite, we performed either oxygen plasma or calcination processes to remove the organic matter. The nature of the phosphate salts was studied by XRD and NMR studies. Amorphous calcium phosphate (ACP) was identified as the mineral phase in the composites submitted to oxygen plasma, whereas crystalline Hap was obtained after calcination. SEM microscopy revealed the formation of porous structures (porosity around 80–85%) in the original composites, as well as in the inorganic matrices obtained after calcination, with porous channels of up to 50 µm in diameter in the former case and of up to 20 µm in the latter. The biocompatibility of the composites was assessed using two different cell lines: C2C12GFP premyoblastic cells and MC3T3 preosteoblastic cells. PMID:28772874

Study of TiO2 anatase nano and microstructures with dominant {001} facets for NO oxidation.

PubMed

Sofianou, Maria-Veronica; Trapalis, Christos; Psycharis, Vassils; Boukos, Nikos; Vaimakis, Tiverios; Yu, Jiaguo; Wang, Wenguang

2012-11-01

TiO(2) anatase nanoplates and hollow microspheres were fabricated by a solvothermal-hydrothermal method using titanium isopropoxide as a titanium precursor and hydrofluoric acid as a capping agent in order to enhance the formation of the {001} crystal facets of the anatase nanocrystals. These different morphological structures of TiO(2) anatase can be achieved by only changing the solvent, keeping the amount of the precursor and of the capping agent identical during the solvothermal-hydrothermal process. After calcination of the samples, the adsorbed fluoride atoms on the {001} crystal facets of the TiO(2) anatase nanocrystals were completely removed from their surface according to XPS analysis. The calcined TiO(2) anatase structures were higher crystallized and the specific surface area of the catalysts increased, enhancing their photocatalytic activity in comparison to the non-calcined TiO(2) anatase structures. All TiO(2) anatase samples with adsorbed as well as non-adsorbed fluoride atoms on their {001} crystal facets, exhibited a higher photonic efficiency than Degussa P25, which was used as a reference. The fluoride free TiO(2) anatase nanoplates exhibited the best photocatalytic activity in oxidizing the NO gas to NO(2) and NO(3) (-).

Reactivity improvement of Ca(OH)2 sorbent using diatomaceous earth (DE) from Aceh Province

NASA Astrophysics Data System (ADS)

Mariana, M.; Mahidin, M.; Mulana, F.; Agam, T.; Hafdiansyah, F.

2018-04-01

In this study, the diatomaceous earth (DE) from Aceh Province was used to increase the reactivity of Ca(OH)2sorbent. The high silica (SiO2) content of about 97% in the diatomaceous earth allows the increasing reactivity of Ca(OH)2sorbent by forming calcium silicate hydrate (CSH). The CSH improved the porosity characteristic of the sorbent. The improvement process was performed by mixing Ca(OH)2sorbent, diatomaceous earth and water in a beaker glass at the Ca(OH)2/DE weight ratio of 1:10 for 2 hand then dried at 120 °C for 24 h. The dried sorbent was calcined at 500 °C and 800 °C for 2 h. The activated sorbent was characterized using Scanning Electron Microscopy (SEM) for the morphological properties; X- Ray Diffraction (XRD) for the materials characteristics. The adsorption capacity of thesorbent was tested by methylene blue adsorption. The results showed that the Ca(OH)2/DEsorbent had a higher porosity than the Ca(OH)2 adsorbent.The results also showed that Ca(OH)2/DE which was calcined at higher temperature of 800 °C had a higher adsorption capacity compared to Ca(OH)2/DE which was calcined at lower temperature of 500 °C.

Hexagonal ZnO porous plates prepared from microwave synthesized layered zinc hydroxide sulphate via thermal decomposition

DOE Office of Scientific and Technical Information (OSTI.GOV)

Machovsky, Michal, E-mail: machovsky@ft.utb.cz; Polymer Centre, Faculty of Technology, Tomas Bata University in Zlin, Nam. T.G. Masaryka 275, 762 72 Zlin; Kuritka, Ivo, E-mail: ivo@kuritka.net

2013-10-15

Graphical abstract: - Highlights: • Zinc hydroxy sulphate was synthesized in 3 min via microwave hydrothermal route. • Zinc hydroxy sulphate was converted into mesh like porous ZnO by calcining at 900°. • The process of transformation is topotactic. - Abstract: Layered zinc hydroxide sulphate (ZHS) was prepared by microwave-assisted hydrothermal precipitation of zinc sulphate monohydrate with hexamethylenetetramine. Under ambient conditions, the structure of ZHS determined by X-ray diffraction (XRD) was found to be a mixture of zinc hydroxide sulphate pentahydrate Zn{sub 4}SO{sub 4}(OH){sub 6}·5H{sub 2}O and tetrahydrate Zn{sub 4}SO{sub 4}(OH){sub 6}·4H{sub 2}O. Fourier transform infrared (FTIR) spectroscopy was usedmore » for characterization of the prepared materials. Based on the interpretation of ZHS's thermal decomposition profile obtained by thermogravimetric analysis, ZnO of high purity was prepared by calcination at 900 °C for 2 h. The structure of the resulting ZnO was confirmed by the XRD. The morphology examination by scanning electron microscopy revealed a porous mesh-like ZnO structure developed from the ZHS precursor at the expense of mass removal due to the release of water and sulphate during the calcination.« less

40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 22 2012-07-01 2012-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 21 2011-07-01 2011-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment... and Calciner Emissions Factors for Fossil Fuel-Based CH4 and N2O Fuel Fossil fuel-based emissions...

Integrated photooxidative-extractive desulfurization system for fuel oil using Cu, Fe and Cu-Fe/TiO2 and eutectic based ionic liquids: Effect of calcination temperature and duration

NASA Astrophysics Data System (ADS)

Zaid, Hayyiratul Fatimah Mohd; Kait, Chong Fai; Mutalib, Mohamed Ibrahim Abdul

2014-10-01

Photocatalyts TiO2 doped with Cu, Fe and Cu-Fe metal at different calcination temperature and duration were successfully prepared and characterized. Photocatalytic oxidative desulfurization of model oil containing dibenzothiophene as the sulfur compound (100 ppm) using the prepared photocatalyst was investigated. The photocatalyst calcined at 500°C and duration of 1 h showed the best performance.

40 CFR Table Aa-2 to Subpart Aa of... - Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Kraft Lime Kiln and Calciner Emissions Factors for CH4 and N2O AA Table AA-2 to Subpart AA of Part 98 Protection of Environment ENVIRONMENTAL... Manufacturing Pt. 98, Subpt. AA, Table AA -2 Table AA-2 to Subpart AA of Part 98—Kraft Lime Kiln and Calciner...

Evaluation of blends bauxite-calcination-method red mud with other industrial wastes as a cementitious material: properties and hydration characteristics.

PubMed

Zhang, Na; Liu, Xiaoming; Sun, Henghu; Li, Longtu

2011-01-15

Red mud is generated from alumina production, and its disposal is currently a worldwide problem. In China, large quantities of red mud derived from bauxite calcination method are being discharged annually, and its utilization has been an urgent topic. This experimental research was to evaluate the feasibility of blends red mud derived from bauxite calcination method with other industrial wastes for use as a cementitious material. The developed cementitious material containing 30% of the bauxite-calcination-method red mud possessed compressive strength properties at a level similar to normal Portland cement, in the range of 45.3-49.5 MPa. Best compressive strength values were demonstrated by the specimen RSFC2 containing 30% bauxite-calcination-method red mud, 21% blast-furnace slag, 10% fly ash, 30% clinker, 8% gypsum and 1% compound agent. The mechanical and physical properties confirm the usefulness of RSFC2. The hydration characteristics of RSFC2 were characterized by XRD, FTIR, (27)Al MAS-NMR and SEM. As predominant hydration products, ettringite and amorphous C-S-H gel are principally responsible for the strength development of RSFC2. Comparing with the traditional production for ordinary Portland cement, this green technology is easier to be implemented and energy saving. This paper provides a key solution to effectively utilize bauxite-calcination-method red mud. Copyright © 2010 Elsevier B.V. All rights reserved.

Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports

PubMed Central

Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H.

2013-01-01

Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/AlS.G.) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/AlS.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/AlS.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size. PMID:28809270

Hydrogen Production by Steam Reforming of Ethanol over Nickel Catalysts Supported on Sol Gel Made Alumina: Influence of Calcination Temperature on Supports.

PubMed

Yaakob, Zahira; Bshish, Ahmed; Ebshish, Ali; Tasirin, Siti Masrinda; Alhasan, Fatah H

2013-05-30

Selecting a proper support in the catalyst system plays an important role in hydrogen production via ethanol steam reforming. In this study, sol gel made alumina supports prepared for nickel (Ni) catalysts were calcined at different temperatures. A series of (Ni/Al S.G. ) catalysts were synthesized by an impregnation procedure. The influence of varying the calcination temperature of the sol gel made supports on catalyst activity was tested in ethanol reforming reaction. The characteristics of the sol gel alumina supports and Ni catalysts were affected by the calcination temperature of the supports. The structure of the sol gel made alumina supports was transformed in the order of γ → (γ + θ) → θ-alumina as the calcination temperature of the supports increased from 600 °C to 1000 °C. Both hydrogen yield and ethanol conversion presented a volcano-shaped behavior with maximum values of 4.3 mol/mol ethanol fed and 99.5%, respectively. The optimum values were exhibited over Ni/Al S.G800 (Ni catalyst supported on sol gel made alumina calcined at 800 °C). The high performance of the Ni/Al S.G800 catalyst may be attributed to the strong interaction of Ni species and sol gel made alumina which lead to high nickel dispersion and small particle size.

Compositional inhomogeneityand segregation in (K 0.5Na 0.5)NbO 3 ceramics

DOE PAGES

Chen, Kepi; Tang, Jing; Chen, Yan

2016-03-11

The effects of the calcination temperature of (K 0.5Na 0.5)NbO 3 (KNN) powder on the sintering and piezoelectric properties of KNN ceramics have been investigated in this report. KNN powders are synthesized via the solid-state approach. Scanning electron microscopy and X-ray diffraction characterizations indicate that the incomplete reaction at 700 °C and 750 °C calcination results in the compositional inhomogeneity of the K-rich and Na-rich phases while the orthorhombic single phase is obtained after calcination at 900 °C. During the sintering, the presence of the liquid K-rich phase due to the lower melting point has a significant impact on themore » densification, the abnormal grain growth and the deteriorated piezoelectric properties. From the standpoint of piezoelectric properties, the optimal calcination temperature obtained for KNN ceramics calcined at this temperature is determined to be 800 °C, with piezoelectric constant d 33=128.3 pC/N, planar electromechanical coupling coefficient k p=32.2%, mechanical quality factor Q m=88, and dielectric loss tan δ=2.1%.« less

Conductivity dependence of lithium diffusivity and electrochemical performance for electrospun TiO2 fibers

NASA Astrophysics Data System (ADS)

Qing, Rui; Liu, Li; Bohling, Christian; Sigmund, Wolfgang

2015-01-01

TiO2 is one of the most exciting anode candidates for safe application in lithium ion batteries. However, its low intrinsic electronic conductivity limits application. In this paper, a simple sol-gel based route is presented to produce nanosize TiO2 fibers with 119 ± 27 nm diameters via electrospinning. Subsequent calcination in various atmospheres was applied to achieve anatase and anatase-rutile mixed phase crystallites with and without carbon coating. The crystallite size was 5 nm for argon calcined fibers and 13-20 nm for air calcined fibers. Argon calcined TiO2 nanofibers exhibited electronic conductivity orders of magnitude higher than those of air-calcined samples. Lithium diffusivity was increased by one time and specific capacity by 26.9% due to the enhanced conductivity. It also had a different intercalation mechanism of lithium. Hydrogen post heat-treatment was found to benefit electronic conductivity (by 3-4.5 times), lithium diffusivity (1.5-2 times) and consequently the high rate performance of the TiO2 nanofibers (over 80%). The inner mechanism and structure-property relations among these parameters were also discussed.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Chen, Kepi; Tang, Jing; Chen, Yan

The effects of the calcination temperature of (K 0.5Na 0.5)NbO 3 (KNN) powder on the sintering and piezoelectric properties of KNN ceramics have been investigated in this report. KNN powders are synthesized via the solid-state approach. Scanning electron microscopy and X-ray diffraction characterizations indicate that the incomplete reaction at 700 °C and 750 °C calcination results in the compositional inhomogeneity of the K-rich and Na-rich phases while the orthorhombic single phase is obtained after calcination at 900 °C. During the sintering, the presence of the liquid K-rich phase due to the lower melting point has a significant impact on themore » densification, the abnormal grain growth and the deteriorated piezoelectric properties. From the standpoint of piezoelectric properties, the optimal calcination temperature obtained for KNN ceramics calcined at this temperature is determined to be 800 °C, with piezoelectric constant d 33=128.3 pC/N, planar electromechanical coupling coefficient k p=32.2%, mechanical quality factor Q m=88, and dielectric loss tan δ=2.1%.« less

Au@Y 2O 3:Eu 3+ rare earth oxide hollow sub-microspheres with encapsulated gold nanoparticles and their optical properties

NASA Astrophysics Data System (ADS)

Min, Yu-Lin; Wan, Yong; Yu, Shu-Hong

2009-01-01

A facile method to synthesize novel Au@Y 2O 3:Eu 3+ hollow sub-microspheres encapsulated with moveable gold nanoparticle core and Y 2O 3:Eu 3+ as shell via two-step coating processes and a succeeding calcination process has been developed. Silica coating on citrate-stabilized gold nanoparticles with a size of 25 nm can be obtained through a slightly modified Stöber process. Gold particles coated with double shell silica and Eu doped Y(OH) 3 can be obtained by coating on the Au@SiO 2 spheres through simply adding Y(NO 3) 3, Eu(NO 3) 3 and an appropriate quantity of NH 3·H 2O. Au@Y 2O 3:Eu 3+ hollow sub-microspheres with moveable individual Au nanoparticle as core can be obtained after calcination of Au@Y 2O 3:Eu 3+ particles at 600 °C for 2 h. These new core-shell structures with encapsulated gold nanoparticles have combined optical properties of both the Au nanoparticles and the Y 2O 3:Eu 3+ phosphor materials which might have potential applications.

Treatment options for low-level radiologically contaminated ORNL filtercake

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lee, Hom-Ti; Bostick, W.D.

1996-04-01

Water softening sludge (>4000 stored low level contaminated drums; 600 drums per year) generated by the ORNL Process Waste Treatment Plant must be treated, stabilized, and placed in safe storage/disposal. The sludge is primarily CaCO{sub 3} and is contaminated by low levels of {sup 90}Sr and {sup 137}Cs. In this study, microwave sintering and calcination were evaluated for treating the sludge. The microwave melting experiments showed promise: volume reductions were significant (3-5X), and the waste form was durable with glass additives (LiOH, fly ash). A commercial vendor using surrogate has demonstrated a melt mineralization process that yields a dense monolithicmore » waste form with a volume reduction factor (VR) of 7.7. Calcination of the sludge at 850-900 C yielded a VR of 2.5. Compaction at 4500 psi increased the VR to 4.2, but the compressed form is not dimensionally stable. Addition of paraffin helped consolidate fines and yielded a VR of 3.5. In conclusion, microwave melting or another form of vitrification is likely to be the best method; however for immediate implementation, the calculation/compaction/waxing process is viable.« less

Spectroscopic observations of nanosized TiO2 by the hydrothermal method

NASA Astrophysics Data System (ADS)

Zikriya, Mohamed; Nadaf, Y. F.; Bharathy, P. Vijai; Renuka, C. G.

2018-05-01

Metal oxides are useful materials that have various applications in advanced field such as, in view of their different properties, hardness, thermal dependability and compound resistance. Novel utilizations of the nanostructures of these oxides are drawing in critical enthusiasm as new preparation process are created and new structures are described. Hydrothermal synthesis is a fruitful procedure to prepare different sensitive structures of metal oxides on the scales from a couple to several nanometres, particularly, the hugely scattered middle structures which are hardly through pyro-preparation. Titanium dioxide nanocrystals are synthesis by a hydrolysis procedure of metatitanic acid. Nano precious crystal of different sizes is procure in the after calcinations from 150 to 225°C. Raman scattering was utilized to examine the advancement of the anatase stage in the nano crystal during calcinations.

Data on calcium oxide and cow bone catalysts used for soybean biodiesel production.

PubMed

Ayodeji, Ayoola A; Blessing, Igho E; Sunday, Fayomi O

2018-06-01

Biodiesel was produced from soybean oil using calcium oxide and cow bone as heterogeneous catalysts, through transesterification process. The soybean oil used was characterized using gas chromatography mass spectrometer (GCMS) and the cow bone catalyst produced was characterized X-ray fluorescence (XRF) spectrometer. The effects of the variation of methanol/oil mole ratio, catalyst concentration and reaction temperature on biodiesel yield during the transesterification of soybean oil were investigated. Reaction time of 3 h and stirring rate of 500 rpm were kept constant. Using Response Optimizer (Minitab 17), the optimum conditions for biodiesel production were established. It was observed that the calcination of cow bone catalyst enhanced its conversion to apatite-CaOH. Also, the results obtained showed that the performance trends of calcined cow bone catalyst and the conventional CaO catalyst were similar.

Calcinated tea and cellulose composite films and its dielectric and lead adsorption properties.

PubMed

Jayaramudu, Tippabattini; Varaprasad, Kokkarachedu; Kim, Hyun Chan; Kafy, Abdullahil; Kim, Jung Woong; Kim, Jaehwan

2017-09-01

In this paper, calcinated tea and cellulose composite (CTCC) films were fabricated via solution casting method. Chemical structure, morphology, crystallinity and thermal stability of the fabricated films were characterized by using Fourier transform infrared spectroscopy, scanning electron microscopy, X-ray diffraction and thermogravimetric analysis. The effect of calcinated tea loading on the properties of the prepared CTCC films was studied. The results suggest that the prepared CTCC films show higher mechanical properties, thermal stability and dielectric constant than the neat cellulose film. In addition, the CTCC films adsorb Pb 2+ ions and its adsorption performance depends on the calcinated tea content and pH level. The CTCC films are useful for sensors, flexible capacitor as well as lead adsorption applications. Copyright © 2017 Elsevier Ltd. All rights reserved.

Advanced Ceramic Technology for Space Applications at NASA MSFC

NASA Technical Reports Server (NTRS)

Alim, Mohammad A.

2003-01-01

The ceramic processing technology using conventional methods is applied to the making of the state-of-the-art ceramics known as smart ceramics or intelligent ceramics or electroceramics. The sol-gel and wet chemical processing routes are excluded in this investigation considering economic aspect and proportionate benefit of the resulting product. The use of ceramic ingredients in making coatings or devices employing vacuum coating unit is also excluded in this investigation. Based on the present information it is anticipated that the conventional processing methods provide identical performing ceramics when compared to that processed by the chemical routes. This is possible when sintering temperature, heating and cooling ramps, peak temperature (sintering temperature), soak-time (hold-time), etc. are considered as variable parameters. In addition, optional calcination step prior to the sintering operation remains as a vital variable parameter. These variable parameters constitute a sintering profile to obtain a sintered product. Also it is possible to obtain identical products for more than one sintering profile attributing to the calcination step in conjunction with the variables of the sintering profile. Overall, the state-of-the-art ceramic technology is evaluated for potential thermal and electrical insulation coatings, microelectronics and integrated circuits, discrete and integrated devices, etc. applications in the space program.

Cognitive Food Processing in Binge-Eating Disorder: An Eye-Tracking Study.

PubMed

Sperling, Ingmar; Baldofski, Sabrina; Lüthold, Patrick; Hilbert, Anja

2017-08-19

Studies indicate an attentional bias towards food in binge-eating disorder (BED); however, more evidence on attentional engagement and disengagement and processing of multiple attention-competing stimuli is needed. This study aimed to examine visual attention to food and non-food stimuli in BED. In n = 23 participants with full-syndrome and subsyndromal BED and n = 23 individually matched healthy controls, eye-tracking was used to assess attention to food and non-food stimuli during a free exploration paradigm and a visual search task. In the free exploration paradigm, groups did not differ in their initial fixation position. While both groups fixated non-food stimuli significantly longer than food stimuli, the BED group allocated significantly more attention towards food than controls. In the visual search task, groups did not differ in detection times. However, a significant detection bias for food was found in full-syndrome BED, but not in controls. An increased initial attention towards food was related to greater BED symptomatology and lower body mass index (BMI) only in full-syndrome BED, while a greater maintained attention to food was associated with lower BMI in controls. The results suggest food-biased visual attentional processing in adults with BED. Further studies should clarify the implications of attentional processes for the etiology and maintenance of BED.

Cognitive Food Processing in Binge-Eating Disorder: An Eye-Tracking Study

PubMed Central

Sperling, Ingmar; Lüthold, Patrick; Hilbert, Anja

2017-01-01

Studies indicate an attentional bias towards food in binge-eating disorder (BED); however, more evidence on attentional engagement and disengagement and processing of multiple attention-competing stimuli is needed. This study aimed to examine visual attention to food and non-food stimuli in BED. In n = 23 participants with full-syndrome and subsyndromal BED and n = 23 individually matched healthy controls, eye-tracking was used to assess attention to food and non-food stimuli during a free exploration paradigm and a visual search task. In the free exploration paradigm, groups did not differ in their initial fixation position. While both groups fixated non-food stimuli significantly longer than food stimuli, the BED group allocated significantly more attention towards food than controls. In the visual search task, groups did not differ in detection times. However, a significant detection bias for food was found in full-syndrome BED, but not in controls. An increased initial attention towards food was related to greater BED symptomatology and lower body mass index (BMI) only in full-syndrome BED, while a greater maintained attention to food was associated with lower BMI in controls. The results suggest food-biased visual attentional processing in adults with BED. Further studies should clarify the implications of attentional processes for the etiology and maintenance of BED. PMID:28825607

The Research Process on Converter Steelmaking Process by Using Limestone

NASA Astrophysics Data System (ADS)

Tang, Biao; Li, Xing-yi; Cheng, Han-chi; Wang, Jing; Zhang, Yun-long

2017-08-01

Compared with traditional converter steelmaking process, steelmaking process with limestone uses limestone to replace lime partly. A lot of researchers have studied about the new steelmaking process. There are much related research about material balance calculation, the behaviour of limestone in the slag, limestone powder injection in converter and application of limestone in iron and steel enterprises. The results show that the surplus heat of converter can meet the need of the limestone calcination, and the new process can reduce the steelmaking process energy loss in the whole steelmaking process, reduce carbon dioxide emissions, and improve the quality of the gas.

Use of soft hydrothermal processing to improve and recycle bedding for laboratory animals.

PubMed

Miyamoto, T; Li, Z; Kibushi, T; Yamasaki, N; Kasai, N

2008-10-01

Cage bedding for laboratory rodents can influence animal wellbeing and thus the experimental data. In addition, a large amount of used bedding containing excrement is discharged as medical waste from life science institutes and breeding companies. We developed a ground-breaking system to improve fresh bedding and recycle used bedding by applying a soft hydrothermal process with high-temperature and high-pressure dry steam. The system removes both harmful organic components and aromatic hydrocarbons that can affect animals' metabolism. The purpose of the present study was to evaluate the chemical and physical properties of the improved fresh bedding and the recycled used bedding treated by the system. The results showed that 68-99% of the predominant aromatic hydrocarbons were removed from fresh bedding treated at 0.35 MPa and 140 degrees C for 120 min ('improved bedding'). In addition, 59.4-99.0% of predominant harmful organic compounds derived from excrement were removed from used bedding treated at 0.45 MPa and 150 degrees C for 60 min ('recycled bedding'). The soft hydrothermal treatment increased the number of acidic functional groups on the bedding surface and gave it the high adsorptive efficiency of ammonia gas. Harmful substances such as microorganisms, heavy metals and pesticides decreased below the detection limit. The results clearly showed that the improved and recycled bedding is safer for laboratory rodents and has the potential to ameliorate conditions in primary and secondary enclosures (e.g. cages and animal rooms) used for maintaining laboratory animals. This process may be one of the most advanced techniques in providing an alternative to softwood and other bedding, economizing through the recycling of used bedding and reducing bedding waste from animal facilities.

Behavior of radioactive iodine and technetium in the spray calcination of high-level waste

NASA Astrophysics Data System (ADS)

Knox, C. A.; Farnsworth, R. K.

1981-08-01

The Remote Laboratory-Scale Waste Treatment Facility (RLSWTF) was designed and built as a part of the High-Level Waste Immobilization Program (now the High-Level Waste Process Development Program) at the Pacific Northwest Laboratory. In facility, installed in a radiochemical cell, is described in which installed in a radiochemical cell is described in which small volumes of radioactive liquid wastes can be solidified, the process off gas can be analyzed, and the methods for decontaminating this off gas can be tested. During the spray calcination of commercial high-level liquid waste spiked with Tc-99 and I-131 and 31 wt% loss of I-131 past the sintered-metal filters. These filters and venturi scrubber were very efficient in removing particulates and Tc-99 from the the off-gas stream. Liquid scrubbers were not efficient in removing I-131 as 25% of the total lost went to the building off-gas system. Therefore, solid adsorbents are needed to remove iodine. For all future operations where iodine is present, a silver zeolite adsorber is to be used.

Effect of microwave-assisted sintering on dielectric properties of CaCu3Ti4O12 ceramic

NASA Astrophysics Data System (ADS)

Rani, Suman; Ahlawat, Neetu; Punia, R.; Kundu, R. S.; Ahlawat, N.

2016-05-01

In this present work, CaCu3Ti4O12 (CCTO) was synthesized by conventional solid-state reaction technique. The synthesis process was carried out in two phases; by conventional process (calcination and sintering at 1080°C for 10 hours) and phase II involves the micro assisted pre sintering of conventionally calcined CCTO for very short soaking time of 30 min at 1080°C in a microwave furnace followed by sintering at 1080°C for 10 hours in conventional furnace. X-ray diffraction (XRD) patterns confirmed the formation of single phase ceramic. Dielectric properties were studied over the frequency range from 50Hz -5MHz at temperatures (273K-343K). It was observed that pre- microwave sintering enhance the dielectric constant values from 10900 to 11893 and respectively reduces the dielectric loss values from 0.49 to 0.34 at room temperature(1 KHz). CCTO ceramics which are found desirable for many technological applications. The effect is more pronounced at low frequencies of applied electric field.

Development of high Tc (greater than 110K) Bi, Tl and Y-based materials as superconducting circuit elements

NASA Technical Reports Server (NTRS)

Haertling, Gene; Grabert, Gregory; Gilmour, Phillip

1991-01-01

Experimental work was continued on the development and characterization of bulk and hot pressed powders and tapecast materials in the Bi-Sr-Ca-Cu-O and Tl-Ba-Ca-Cu-O systems. A process for producing warp-free, sintered, superconducting tapes of Bi composition Bi1Sr2Ca2 Cu3O(x) was established. The procedure requires a triple calcination at 830 C for 24 hours and sintering at 845 C from 20 to 200 hours. Hot pressing the triple calcined powder at 845 C for 6 hours at 5000 psi yielded a dense material, which on further heat treatment at 845 C for 24 hours, exhibited a Tc of 108.2K. The Bi compositions were found to be much less oxygen sensitive than the Y compositions. This was especially noted in the case of the hot pressed materials which were superconducting as hot pressed, a condition that could not be achieved in the Y compositions. Safire-type grounding links are in the process of being fabricated from these materials.

Synthesis and photocatalytic activity of sepiolite supportednano-TiO2 composites prepared by a mild solid-state sintering process

NASA Astrophysics Data System (ADS)

Liao, L. M.; Wang, Z. Q.; Liang, H.; Feng, J.; Zhang, D.

2016-08-01

Supported nano-TiO2photocatalysts play an important role in water environment restoration because of their potential application to photocatalytic degradation of organic contaminants in waste water. With sepiolite as the support, the nano-TiO2/sepiolite composite photocatalysts were synthesized by an easily operated and mild solid-state sintering process.The microstructureand photocatalytic property of the sepiolite supportednano-TiO2 composites were characterized and analyzed by X-ray diffraction spectroscopy, UV-Visible spectroscopy and fluorescence spectroscopy. In addition, the influences of calcination temperature and load ratios on the photocatalytic activity of sepiolite supported nano-TiO2 composites were studied.The results indicated that appropriate ratios of sepiolite supports to nano-TiO2contributed to uniform dispersion of nanoparticles, and enhanced the absorption ability within the UV-Vis range, and consequently increased the photocatalytic activity of the composites.Under the preparation conditions of 90 wt. % TiO2 loading and calcinated at 400 °C, a maximum in photocatalytic activity ofnano-TiO2 sepiolite composite was obtained.

Nonaqueous solution synthesis process for preparing oxide powders of lead zirconate titanate and related materials

DOEpatents

Voigt, J.A.; Sipola, D.L.; Tuttle, B.A.; Anderson, M.T.

1999-06-01

A process is disclosed for producing powders of perovskite-type compounds which comprises mixing a metal alkoxide solution with a lead acetate solution to form a homogeneous, clear metal solution, adding an oxalic acid/n-propanol solution to this metal solution to form an easily filterable, free-flowing precursor powder and then calcining this powder. This process provides fine perovskite-phase powders with ferroelectric properties which are particularly useful in a variety of electronic applications. 4 figs.

Nonaqueous solution synthesis process for preparing oxide powders of lead zirconate titanate and related materials

DOEpatents

Voigt, James A.; Sipola, Diana L.; Tuttle, Bruce A.; Anderson, Mark T.

1999-01-01

A process for producing powders of perovskite-type compounds which comprises mixing a metal alkoxide solution with a lead acetate solution to form a homogeneous, clear metal solution, adding an oxalic acid/n-propanol solution to this metal solution to form an easily filterable, free-flowing precursor powder and then calcining this powder. This process provides fine perovskite-phase powders with ferroelectric properties which are particularly useful in a variety of electronic applications.

Effects of pH and calcination temperature on structural and optical properties of alumina nanoparticles

NASA Astrophysics Data System (ADS)

Amirsalari, A.; Farjami Shayesteh, S.

2015-06-01

In this study, we describe the synthesis of alumina nanoparticles using a chemical wet method in at varying pH. The optimized prepared particles with pH equals to 9 were calcined at various temperatures. For characterization of structural and optical properties of nanoparticles had been used X-ray diffraction, Infrared Fourier transform spectroscopy, field effect-scanning electron microscopy, photoluminescence and ultraviolet-visible spectroscopy. The results revealed that the nanoparticles calcined at 500 °C consist of an Al2O3 tetragonal structure and tetragonal distortion decreases with increasing calcination temperature up to 750 °C then increased with increasing temperature. Another phase similar to γ-Al2O3 was formed instead of δ-Al2O3 in the transition sequence from the γ to θ phase. FT-IR analysis; suggests that there are a few different types of functional groups on the surface of the alumina nanoparticles such as hydroxy groups and oxy groups. The transmittance spectra showed that the absorption bands in the UV region strongly depend on the calcination temperature. Moreover, the results showed that alumina has an optical direct band gap and that the energy gap decreases with increasing the calcination temperature and pH of the reaction. Luminescence spectra showed that some luminescent centers such as OH-related radiative centers and oxygen vacancies (F, F22+ and F2 centers) centers exist in the nanoparticles.

Catalytic dehydration of fructose to 5-hydroxymethylfurfural over Nb2O5 catalyst in organic solvent.

PubMed

Wang, Fenfen; Wu, Hai-Zhen; Liu, Chun-Ling; Yang, Rong-Zhen; Dong, Wen-Sheng

2013-03-07

The catalytic dehydration of fructose to 5-hydroxymethylfurfural (HMF) in DMSO was performed over Nb2O5 derived from calcination of niobic acid at various temperatures (300-700 °C). The catalysts were characterized by powder X-ray diffraction, N2 physical adsorption, temperature-programed desorption of NH3, n-butylamine titration using Hammett indicators, infrared spectroscopy of adsorbed pyridine, and X-ray photoelectron spectroscopy. It was found that both catalytic activity and surface acid sites decrease with increasing calcination temperatures. The Nb2O5 derived from calcination of niobic acid at 400 °C reveals the maximum yield of HMF among all the catalysts, although the amount of acid sites on the catalyst is lower than that on the sample calcined at 300 °C. The results suggest that the presence of larger amounts of strong acid sites on the surface of the Nb2O5 calcined at 300 °C may promote side reactions. The Nb2O5 prepared at 400 °C shows 100% fructose conversion with 86.2% HMF yield in DMSO at 120 °C after 2 h. The activity of the catalyst decreases gradually during recycle because of coke deposition; however, it can be fully recovered by calcination at 400 °C for 2 h, suggesting that this catalyst is of significance for practical applications. Copyright © 2012 Elsevier Ltd. All rights reserved.

Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization.

PubMed

Yan, Liyun; Lu, Xiaofeng; Wang, Quanhai; Guo, Qiang

2014-11-01

An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO 2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO 2 from by-products was summarized. Results showed that the SO 2 content in the calciner gas was increased by more than 10 times under a lower excess air coefficient, a higher feed rate, a lower crystal water in by-products, and a higher feed port position. For the tests conducted under the excess air coefficient above and below one, the effect of the furnace temperature on the SO 2 content in the calciner gas was reversed. Results of activity analysis indicate that particles of MgO generated under the calcination temperature of 900-1,000°C had a high activity. In contrast, due to the slight sintering, MgO generated under the calcination temperature of 1,100°C had a low activity. To recycle SO 2 as well as MgO, a temperature range of 900-927°C for TE103 is proposed. These studies will prompt the desulfurization market diversification, reduce the sulfur's dependence on imports for making sulfuric acid, be meaningful to balance the usage of the natural resource in China, and be regarded as a reference for the development of this technology for other similar developing countries.

Additional Effects of Silver Nanoparticles on Bactericidal Efficiency Depend on Calcination Temperature and Dip-Coating Speed▿

PubMed Central

Le, Nhung Thi Tuyet; Nagata, Hirofumi; Aihara, Mutsumi; Takahashi, Akira; Okamoto, Toshihiro; Shimohata, Takaaki; Mawatari, Kazuaki; Kinouchi, Yhosuke; Akutagawa, Masatake; Haraguchi, Masanobu

2011-01-01

There is an increasing interest in the application of photocatalytic properties for disinfection of surfaces, air, and water. Titanium dioxide is widely used as a photocatalyst, and the addition of silver reportedly enhances its bactericidal action. However, the synergy of silver nanoparticles and TiO2 is not well understood. The photocatalytic elimination of Bacillus atrophaeus was examined under different calcination temperatures, dip-coating speeds, and ratios of TiO2, SiO2, and Ag to identify optimal production conditions for the production of TiO2- and/or TiO2/Ag-coated glass for surface disinfection. Photocatalytic disinfection of pure TiO2 or TiO2 plus Ag nanoparticles was dependent primarily on the calcination temperature. The antibacterial activity of TiO2 films was optimal with a high dip-coating speed and high calcination temperature (600°C). Maximal bacterial inactivation using TiO2/Ag-coated glass was also observed following high-speed dip coating but with a low calcination temperature (250°C). Scanning electron microscopy (SEM) showed that the Ag nanoparticles combined together at a high calcination temperature, leading to decreased antibacterial activity of TiO2/Ag films due to a smaller surface area of Ag nanoparticles. The presence of Ag enhanced the photocatalytic inactivation rate of TiO2, producing a more pronounced effect with increasing levels of catalyst loading. PMID:21724887

Sorting it out: bedding particle size and nesting material processing method affect nest complexity.

PubMed

Robinson-Junker, Amy; Morin, Amelia; Pritchett-Corning, Kathleen; Gaskill, Brianna N

2017-04-01

As part of routine husbandry, an increasing number of laboratory mice receive nesting material in addition to standard bedding material in their cages. Nesting material improves health outcomes and physiological performance in mice that receive it. Providing usable nesting material uniformly and efficiently to various strains of mice remains a challenge. The aim of this study was to determine how bedding particle size, method of nesting material delivery, and processing of the nesting material before delivery affected nest building in mice of strong (BALB/cAnNCrl) and weak (C3H/HeNCrl) gathering abilities. Our data suggest that processing nesting material through a grinder in conjunction with bedding material, although convenient for provision of bedding with nesting material 'built-in', negatively affects the integrity of the nesting material and subsequent nest-building outcomes. We also found that C3H mice, previously thought to be poor nest builders, built similarly scored nests to those of BALB/c mice when provided with unprocessed nesting material. This was true even when nesting material was mixed into the bedding substrate. We also observed that when nesting material was mixed into the bedding substrate, mice of both strains would sort their bedding by particle size more often than if it were not mixed in. Our findings support the utility of the practice of distributing nesting material mixed in with bedding substrate, but not that of processing the nesting material with the bedding in order to mix them.

The preparation and characterization of La doped TiO 2 nanoparticles and their photocatalytic activity

NASA Astrophysics Data System (ADS)

Liqiang, Jing; Xiaojun, Sun; Baifu, Xin; Baiqi, Wang; Weimin, Cai; Honggang, Fu

2004-10-01

In this paper, pure and La doped TiO2 nanoparticles with different La content were prepared by a sol-gel process using Ti (OC4H9)4 as raw material, and also were characterized by XRD, TG-DTA, TEM, XPS, DRS and Photoluminescence (PL) spectra. We mainly investigated the effects of calcining temperature and La content on the properties and the photocatalytic activity for degrading phenol of as-prepared TiO2 samples, and also discussed the relationships between PL spectra and photocatalytic activity as well as the mechanisms of La doping on TiO2 phase transformation. The results showed that La3+ did not enter into the crystal lattices of TiO2 and was uniformly dispersed onto TiO2 as the form of La2O3 particles with small size, which possibly made La dopant have a great inhibition on TiO2 phase transformation; La dopant did not give rise to a new PL signal, but it could improve the intensity of PL spectra with a appropriate La content, which was possibly attributed to the increase in the content of surface oxygen vacancies and defects after doping La; La doped TiO2 nanoparticles calcined at 600°C exhibited higher photocatalytic activity, indicating that 600°C was an appropriate calcination temperature. The order of photocatalytic activity of La doped TiO2 samples with different La content was as following: 1>1.5>3>0.5>5>0 mol%, which was the same as the order of their PL intensity, namely, the stronger the PL intensity, the higher the photocatalytic activity, demonstrating that there were certain relationships between PL spectra and photocatalytic activity. This could be explained by the points that PL spectra mainly resulted from surface oxygen vacancies and defects during the process of PL, while surface oxygen vacancies and defects could be favorable in capturing the photoinduced electrons during the process of photocatalytic reactions.

[Preparation of porous ceramics based on waste ceramics and its Ni2+ adsorption characteristics].

PubMed

Zhang, Yong-Li; Wang, Cheng-Zhi; Shi, Ce; Shang, Ling-Ling; Ma, Rui; Dong, Wan-Li

2013-07-01

The preparation conditions of porous ceramics were determined by SEM, XRD and FT-IR characterizations as well as the nickel removal ability of porous ceramics to be: the mass fraction w of sesbania powder doped was 4%, and the calcination temperature was 800 degrees C. SEM and pore structure characterization illustrated that calcination caused changes in the structure and morphology of waste ceramics. With the increase of calcination temperature, the specific surface area and pore volume decreased, while the aperture increased. EDS analyses showed that the main elements of both the original waste porcelain powder and the porous ceramics were Si, Al and O. The SEM, XRD and FT-IR characterization of porous ceramics illustrated that the structure of porous ceramics was stable before and after adsorption. The series of experiments of Ni2+ adsorption using these porous ceramics showed that when the dosage of porous ceramics was 10 g x L(-1), the adsorption time was 60 min, the pH value was 6.32, and the concentration of nickel-containing wastewater was below 100 mg x L(-1), the Ni2+ removal of wastewater reached 89.7%. Besides, the porous ceramics showed higher removal efficiency on nickel in the wastewater. The Ni(2+)-containing wastewater was processed by the porous ceramics prepared, and the adsorption dynamics and adsorption isotherms of Ni2+ in wastewater by porous ceramics were investigated. The research results showed that the Ni2+ adsorption process of porous ceramics was in accordance with the quasi second-order kinetic model (R2 = 0.999 9), with Q(e) of 9.09 mg x g(-1). The adsorption process can be described by the Freundlich equation and Langmuir equation, and when the temperature increased from 20 degrees C to 40 degrees C, the maximum adsorption capacity Q(m) increased from 14.49 mg x g(-1) to 15.38 mg x g(-1).

Structural morphology, upconversion luminescence and optical thermometric sensing behavior of Y2O3:Er(3+)/Yb(3+) nano-crystalline phosphor.

PubMed

Joshi, C; Dwivedi, A; Rai, S B

2014-08-14

Infrared-to-visible upconverting rare earths Er(3+)/Yb(3+) co-doped Y2O3 nano-crystalline phosphor samples have been prepared by solution combustion method followed by post-heat treatment at higher temperatures. A slight increase in average crystallite size has been found on calcinations verified by X-ray analysis. Transmission electron microscopy (TEM) confirms the nano-crystalline nature of the as-prepared and calcinated samples. Fourier transform infrared (FTIR) analysis shows the structural changes in as-prepared and calcinated samples. Upconversion and downconversion emission recorded using 976 and 532 nm laser sources clearly demonstrates a better luminescence properties in the calcinated samples as compared to as-prepared sample. Upconversion emission has been quantified in terms of standard chromaticity diagram (CIE) showing a shift in overall upconversion emission of as-prepared and calcinated samples. Temperature sensing behaviour of this material has also been investigated by measurement of fluorescence intensity ratio (FIR) of various signals in green emission in the temperature range of 315 to 555 K under 976 nm laser excitation. Copyright © 2014 Elsevier B.V. All rights reserved.

Crystallite Size-Lattice Strain Estimation and Optical Properties of Mn0.5Zn0.5Fe2O4 Nanoparticles

NASA Astrophysics Data System (ADS)

Indrayana, I. P. T.; Suharyadi, E.

2018-04-01

In the present work, we performed William-Hall plot using uniform deformation model (UDM) to estimate the crystallite size and lattice strain of Mn0.5Zn0.5Fe2O4 with various calcination temperature. The calculated crystallite sizes are 25.86 nm, 29.55 nm and 24.97 nm for nanoparticles which were calcined at a temperature of 600°C, 800°C and 1000°C, consecutively. The strain of nanoparticles has value in the order of 10-3. Controlling the calcination temperature will facilitate a change in crystallinity of nanoparticles and influence their crystallite size and strain of the crystal lattice. The optical band gap energy of samples nanoparticles is in a range of 1.09 eV – 3.30 eV. Increasing calcination temperature increased the direct and indirect band gap energy. The Urbach energy was found to increase with increased of gap energy. These results demonstrated that higher structural and optical properties of Mn0.5Zn0.5Fe2O4 can be obtained from a higher calcination temperature.

Magnetically separable maghemite/montmorillonite composite as an efficient heterogeneous Fenton-like catalyst for phenol degradation.

PubMed

Jin, Mingjie; Long, Mingce; Su, Hanrui; Pan, Yue; Zhang, Qiuzhuo; Wang, Juan; Zhou, Baoxue; Zhang, Yanwu

2017-01-01

To develop highly efficient and conveniently separable iron containing catalysts is crucial to remove recalcitrant organic pollutants in wastewater through a heterogeneous Fenton-like reaction. A maghemite/montmorillonite composite was synthesized by a coprecipitation and calcination method. The physiochemical properties of catalysts were characterized by XRD, TEM, nitrogen physisorption, thermogravimetric analysis/differential scanning calorimetry (TG/DSC), zeta potential, and magnetite susceptibility measurements. The influence of calcination temperatures and reaction parameters was investigated. The calcined composites retain magnetism because the presence of montmorillonite inhibited the growth of γ-Fe 2 O 3 nanoparticles, as well as their phase transition. The catalytic activities for phenol degradation were significantly enhanced by calcinations, which strengthen the interaction between iron oxides and aluminosilicate framework and result in more negatively charged surface. The composite (73 m 2 /g) calcined at 350 °C had the highest catalytic activities, with more than 99 % phenol reduction after only 35 min reaction at pH 3.6. Simultaneously, this catalyst exhibited high stability, low iron leaching, and magnetically separable ability for consecutive usage, making it promising for the removal of recalcitrant organic pollutants in wastewater.

Near-infrared spectroscopy monitoring and control of the fluidized bed granulation and coating processes-A review.

PubMed

Liu, Ronghua; Li, Lian; Yin, Wenping; Xu, Dongbo; Zang, Hengchang

2017-09-15

The fluidized bed granulation and pellets coating technologies are widely used in pharmaceutical industry, because the particles made in a fluidized bed have good flowability, compressibility, and the coating thickness of pellets are homogeneous. With the popularization of process analytical technology (PAT), real-time analysis for critical quality attributes (CQA) was getting more attention. Near-infrared (NIR) spectroscopy, as a PAT tool, could realize the real-time monitoring and control during the granulating and coating processes, which could optimize the manufacturing processes. This article reviewed the application of NIR spectroscopy in CQA (moisture content, particle size and tablet/pellet thickness) monitoring during fluidized bed granulation and coating processes. Through this review, we would like to provide references for realizing automated control and intelligent production in fluidized bed granulation and pellets coating of pharmaceutical industry. Copyright © 2017 Elsevier B.V. All rights reserved.

Preparation of a new Fenton-like catalyst from red mud using molasses wastewater as partial acidifying agent.

PubMed

Wei, Guangtao; Shao, Luhua; Mo, Jihua; Li, Zhongmin; Zhang, Linye

2017-06-01

Using molasses wastewater as partial acidifying agent, a new Fenton-like catalyst (ACRM sm ) was prepared through a simple process of acidification and calcination using red mud as main material. With molasses wastewater, both the free alkali and the chemically bonded alkali in red mud were effectively removed under the action of H 2 SO 4 and molasses wastewater, and the prepared ACRM sm was a near-neutral catalyst. The ACRM sm preparation conditions were as follows: for 3 g of red mud, 9 mL of 0.7 mol/L H 2 SO 4 plus 2 g of molasses wastewater as the acidifying agent, calcination temperature 573 K, and calcination time 1 h. Iron phase of ACRM sm was mainly α-Fe 2 O 3 and trace amount of carbon existed in ACRM sm . The addition of molasses wastewater not only effectively reduced the consumption of H 2 SO 4 in acidification of red mud but also resulted in the generation of carbon and significantly improved the distribution of macropore in prepared ACRM sm . It was found that near-neutral pH of catalyst, generated carbon, and wide distribution of macropore were the main reasons for the high catalytic activity of ACRM sm . The generated carbon and wide distribution of macropore were entirely due to the molasses wastewater added. In degradation of orange II, ACRM sm retained most of its catalytic stability and activity after five recycling times, indicating ACRM sm had an excellent long-term stability in the Fenton-like process. Furthermore, the performance test of settling showed ACRM sm had an excellent settleability. ACRM sm was a safe and green catalytic material used in Fenton-like oxidation for wastewater treatment.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ding, Kun; Wang, Dan; Yang, Ping

Graphical abstract: Anatase TiO{sub 2} nanocaps prepared by HF-assisted chemical etching method exhibit enhanced photocatalytic activity compared with commercial P25 because of HF served as an etching agent to remove doped impurities. - Highlights: • Anatase TiO{sub 2} nanocaps were synthesized by HF etching process. • The optimal conditions of experiment are 700 °C calcination and 0.2 mL HF solution. • The photocatalytic properties was studied upon UV and Visible irradiation. • The unique TiO{sub 2} nanocaps structure shows excellent photocatalytic activity. - Abstract: Anatase titanium dioxide (TiO{sub 2}) nanocaps were created via a four-step process including the preparation ofmore » SiO{sub 2} spheres, the deposition of a TiO{sub 2} layer to fabricate SiO{sub 2}@TiO{sub 2} composite spheres, the calcination for obtaining the crystal structure of anatase phase, and hydrofluoric acid (HF) etching to dissolve SiO{sub 2} cores. The SiO{sub 2}@TiO{sub 2} spheres calcined at 700 °C revealed fine photocatalytic activity. Interestingly, most of samples transformed into TiO{sub 2} nanocaps via HF etching, and TiO{sub 2} nanocaps prepared using optimal conditions exhibited quick degradation (k is 0.052 min{sup −1}) compared with commercial P25 (k is 0.030 min{sup −1}) and the TiO{sub 2} nanostructures etched by a NaOH solution. The excellent photocatalytic performance is attributed to its unique hollow hemispherical nanocaps structure, which is in favor of making full use of incident light. The photocatalysis phenomenon in visible light was also observed after depositing Au nanoparticles on anantase TiO{sub 2} nanocaps.« less

A Comparison of the Greenhouse Impacts of Magnesium Produced By Electrolytic and Pidgeon Processes

NASA Astrophysics Data System (ADS)

Ramakrishnan, Subramania; Koltun, Paul

With a focus on the global warming impact, this paper deals with the cradle-to-gate life cycle study of the following two practical production systems for producing magnesium ingots: (i) Magnesite ore is processed using the Australian Magnesium process to produce anhydrous magnesium chloride, which is then electrolysed to produce magnesium; and (ii) Dolomite ore is calcined to produce magnesium oxide, which is then thermally reduced with ferrosilicon using the Pidgeon process, based on the current practice used in China for magnesium production

Process Technology for Tunable Fischer Tropsch Synthesis Towards Middle Distillate Fuel Fractions

DTIC Science & Technology

2008-08-04

Catalyst Preparation (III) ● Incipient Wetness Used to impregnate Potassium Solution onto Iron (K / Fe atomic ratio = .02). Catalyst dried overnight at T...80oC then calcined for 1 hour at T = 350oC ● Incipient Wetness Used to impregnate Copper Solution onto Iron ( Cu / Fe atomic ratio = .01...Fischer Tropsch technologies that target the production of TP SBF through process, catalyst , and reactor improvements. Investigate Supercritical

40 CFR 60.734 - Monitoring of emissions and operations.

Code of Federal Regulations, 2014 CFR

2014-07-01

... fuller's earth rotary dryer, a gypsum rotary dryer, a gypsum flash calciner, gypsum kettle calciner, an... water column gauge pressure at the level of operation. The liquid flow rate monitoring device must be...

40 CFR 60.734 - Monitoring of emissions and operations.

Code of Federal Regulations, 2013 CFR

2013-07-01

... fuller's earth rotary dryer, a gypsum rotary dryer, a gypsum flash calciner, gypsum kettle calciner, an... water column gauge pressure at the level of operation. The liquid flow rate monitoring device must be...

40 CFR 60.734 - Monitoring of emissions and operations.

Code of Federal Regulations, 2012 CFR

2012-07-01

... fuller's earth rotary dryer, a gypsum rotary dryer, a gypsum flash calciner, gypsum kettle calciner, an... water column gauge pressure at the level of operation. The liquid flow rate monitoring device must be...

40 CFR 60.734 - Monitoring of emissions and operations.

Code of Federal Regulations, 2011 CFR

2011-07-01

... fuller's earth rotary dryer, a gypsum rotary dryer, a gypsum flash calciner, gypsum kettle calciner, an... water column gauge pressure at the level of operation. The liquid flow rate monitoring device must be...

What controls channel form in steep mountain streams?

NASA Astrophysics Data System (ADS)

Palucis, M. C.; Lamb, M. P.

2017-07-01

Steep mountain streams have channel morphologies that transition from alternate bar to step-pool to cascade with increasing bed slope, which affect stream habitat, flow resistance, and sediment transport. Experimental and theoretical studies suggest that alternate bars form under large channel width-to-depth ratios, step-pools form in near supercritical flow or when channel width is narrow compared to bed grain size, and cascade morphology is related to debris flows. However, the connection between these process variables and bed slope—the apparent dominant variable for natural stream types—is unclear. Combining field data and theory, we find that certain bed slopes have unique channel morphologies because the process variables covary systematically with bed slope. Multiple stable states are predicted for other ranges in bed slope, suggesting that a competition of underlying processes leads to the emergence of the most stable channel form.

Characterization of Copper-Manganese-Aluminum-Magnesium Mixed Oxyhydroxide and Oxide Catalysts for Redox Reactions

NASA Astrophysics Data System (ADS)

Baksi, Arnab; Cocke, David L.; Gomes, Andrew; Gossage, John; Riggs, Mark; Beall, Gary; McWhinney, Hylton

Complex multi-metal catalysts require several stages in their preparation. These are: co-mixing, co-precipitation, milling and sol-gel, drying, dehydroxylation, and calcination and sometimes regeneration of the hydroxide by rehydration. These processes require thermal analysis (DTA, TGA, DSC) and accompanying off gas analysis, plus one or more of these: XRD, XPS, SEMEDS, FTIR and UV-VIS. In this study, hydrotalcite, hopcalite and mixed systems were prepared and guided by the above characterization techniques. The systems were initiated by mixing the chlorides or nitrates followed by hydrothermal treatments to produce the hydroxides which were further treated by washing, drying, and calcination. The thermal analysis was critical to guide the preparation through these stages and when combined with structural determination methods considerable understanding of their chemical and physical changes was obtained. The correlations between preparation and characterization will be discussed.

Highly transparent, flexible, and thermally stable superhydrophobic ORMOSIL aerogel thin films.

PubMed

Budunoglu, Hulya; Yildirim, Adem; Guler, Mustafa O; Bayindir, Mehmet

2011-02-01

We report preparation of highly transparent, flexible, and thermally stable superhydrophobic organically modified silica (ORMOSIL) aerogel thin films from colloidal dispersions at ambient conditions. The prepared dispersions are suitable for large area processing with ease of coating and being directly applicable without requiring any pre- or post-treatment on a variety of surfaces including glass, wood, and plastics. ORMOSIL films exhibit and retain superhydrophobic behavior up to 500 °C and even on bent flexible substrates. The surface of the films can be converted from superhydrophobic (contact angle of 179.9°) to superhydrophilic (contact angle of <5°) by calcination at high temperatures. The wettability of the coatings can be changed by tuning the calcination temperature and duration. The prepared films also exhibit low refractive index and high porosity making them suitable as multifunctional coatings for many application fields including solar cells, flexible electronics, and lab on papers.

Positron annihilation lifetime spectroscopy (PALS) study of the as prepared and calcined MFI zeolites

NASA Astrophysics Data System (ADS)

Bosnar, Sanja; Vrankić, Martina; Bosnar, Damir; Ren, Nan; Šarić, Ankica

2017-11-01

The synthesis of high silica zeolites in many cases implies the usage of organic structural direction agents (SDA). However, to manifest their functionalities, the SDA occluded inside the channels of the as-synthesized structure should be removed, usually by a high temperature treatment (calcination). In this paper, the positron annihilation lifetime spectroscopy (PALS) was used to monitor the development of accessible spaces, their sizes and distributions in MFI zeolites, ZSM-5 and silicalite-1 in order to give an additional insight in the process of the SDA removal. For that purpose, a conventional PALS setup with 22Na positron source was applied. It was established that there is a pronounced difference between positron annihilation data for these two zeolites of the same structural type. The samples were additionally analysed by X-ray powder diffraction at room temperature with a crystal structure refinement and thermogravimetry.

Scientific Insights in the Preparation and Characterisation of a Lead-based Naga Bhasma.

PubMed

Nagarajan, S; Krishnaswamy, S; Pemiah, Brindha; Rajan, K S; Krishnan, Umamaheswari; Sethuraman, S

2014-01-01

Naga bhasma is one of the herbo-metallic preparations used in Ayurveda, a traditional Indian System of Medicine. The preparation of Naga bhasma involves thermal treatment of 'Naga' (metallic lead) in a series of quenching liquids, followed by reaction with realgar and herbal constituents, before calcination to prepare a fine product. We have analysed the intermediates obtained during different stages of preparation to understand the relevance and importance of different steps involved in the preparation. Our results show that 'Sodhana' (purification process) removes heavy metals other than lead, apart from making it soft and amenable for trituration. The use of powders of tamarind bark and peepal bark maintains the oxidation state of lead in Jarita Naga (lead oxide) as Pb(2+). The repeated calcination steps result in the formation of nano-crystalline lead sulphide, the main chemical species present in Naga bhasma.

Scientific Insights in the Preparation and Characterisation of a Lead-based Naga Bhasma

PubMed Central

Nagarajan, S.; Krishnaswamy, S.; Pemiah, Brindha; Rajan, K. S.; Krishnan, Umamaheswari; Sethuraman, S.

2014-01-01

Naga bhasma is one of the herbo-metallic preparations used in Ayurveda, a traditional Indian System of Medicine. The preparation of Naga bhasma involves thermal treatment of ‘Naga’ (metallic lead) in a series of quenching liquids, followed by reaction with realgar and herbal constituents, before calcination to prepare a fine product. We have analysed the intermediates obtained during different stages of preparation to understand the relevance and importance of different steps involved in the preparation. Our results show that ‘Sodhana’ (purification process) removes heavy metals other than lead, apart from making it soft and amenable for trituration. The use of powders of tamarind bark and peepal bark maintains the oxidation state of lead in Jarita Naga (lead oxide) as Pb2+. The repeated calcination steps result in the formation of nano-crystalline lead sulphide, the main chemical species present in Naga bhasma. PMID:24799737

Virtual Design of a Four-Bed Molecular Sieve for Exploration

NASA Technical Reports Server (NTRS)

Giesy, T. J.; Coker, R. F.; O'Connor, B. F.; Knox, J. C.

2017-01-01

Aboard the International Space Station, CO2 is removed from the cabin atmosphere by a four-bed molecular sieve (4BMS) process called the Carbon Dioxide Removal Assembly (CDRA).1 This 4BMS process operates by passing the CO2-laden air through a desiccant bed to remove any humidity and then passing the dried air through a sorbent bed to remove the CO2. While one pair of beds is in use, the other pair is thermally regenerated to allow for continuous CO2 removal.

Model-free adaptive control of supercritical circulating fluidized-bed boilers

DOEpatents

Cheng, George Shu-Xing; Mulkey, Steven L

2014-12-16

A novel 3-Input-3-Output (3.times.3) Fuel-Air Ratio Model-Free Adaptive (MFA) controller is introduced, which can effectively control key process variables including Bed Temperature, Excess O2, and Furnace Negative Pressure of combustion processes of advanced boilers. A novel 7-input-7-output (7.times.7) MFA control system is also described for controlling a combined 3-Input-3-Output (3.times.3) process of Boiler-Turbine-Generator (BTG) units and a 5.times.5 CFB combustion process of advanced boilers. Those boilers include Circulating Fluidized-Bed (CFB) Boilers and Once-Through Supercritical Circulating Fluidized-Bed (OTSC CFB) Boilers.

Improving bed turnover time with a bed management system.

PubMed

Tortorella, Frank; Ukanowicz, Donna; Douglas-Ntagha, Pamela; Ray, Robert; Triller, Maureen

2013-01-01

Efficient patient throughput requires a high degree of coordination and communication. Opportunities abound to improve the patient experience by eliminating waste from the process and improving communication among the multiple disciplines involved in facilitating patient flow. In this article, we demonstrate how an interdisciplinary team at a large tertiary cancer center implemented an electronic bed management system to improve the bed turnover component of the patient throughput process.

Fluidized-bed bioreactor process for the microbial solubiliztion of coal

DOEpatents

Scott, Charles D.; Strandberg, Gerald W.

1989-01-01

A fluidized-bed bioreactor system for the conversion of coal into microbially solubilized coal products. The fluidized-bed bioreactor continuously or periodically receives coal and bio-reactants and provides for the production of microbially solubilized coal products in an economical and efficient manner. An oxidation pretreatment process for rendering coal uniformly and more readily susceptible to microbial solubilization may be employed with the fluidized-bed bioreactor.

Effect of pulsation on black liquor gasification. Final report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zinn, B.T.; Jagoda, J.; Jeong, H.

1998-12-01

Pyrolysis is an endothermic process. The heat of reaction is provided either by partial combustion of the waste or by heat transfer from an external combustion process. In one proposed system black liquor is pyrolized in a fluidized bed to which heat is added through a series of pulse combustor tail pipes submerged in the bed material. This system appears promising because of the relatively high heat transfer in pulse combustors and in fluidized beds. Other advantages of pulse combustors are discussed elsewhere. The process is, however, only economically viable if a part of the pyrolysis products can be usedmore » to fire the pulse combustors. The overall goals of this study were to determine: (1) which is the limiting heat transfer rate in the process of transferring heat from the hot combustion products to the pipe, through the pipe, from the tail pipe to the bed and through the bed; i.e., whether increased heat transfer within the pulse combustor will significantly increase the overall heat transfer rate; (2) whether the heat transfer benefits of the pulse combustor can be utilized while maintaining the temperature in the bed within the narrow temperature range required by the process without generating hot spots in the bed; and (3) whether the fuel gas produced during the gasification process can be used to efficiently fire the pulse combustor.« less

77 FR 12491 - Revisions to the California State Implementation Plan, Antelope Valley Air Quality Management...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-03-01

... Coke Calcining Operations-- 01/18/11 06/20/11 Oxides of Sulfur. SJVUAPCD Synthesized Pharmaceutical.... (a) * * * (6) * * * (ix) Petroleum Coke Calcining Operations--Oxides of Sulfur submitted on June 20...

The alcohol-sensing behaviour of SnO2 nanorods prepared by a facile solid state reaction

NASA Astrophysics Data System (ADS)

Gao, F.; Ren, X. P.; Wan, W. J.; Zhao, Y. P.; Li, Y. H.; Zhao, H. Y.

2017-02-01

SnO2 nanorods with the range of 12-85 nm in diameter were fabricated by a facile solid state reaction in the medium of NaCl-KCl mixture at room temperature and calcined at 600, 680, 760 and 840 oC, respectively. The XRD, TEM and XPS were employed to characterize the structure and morphology of the SnO2 nanorods. The influence of the calcination temperature on the gas sensing behaviour of the SnO2 nanorods with different diameter was investigated. The result showed that all the sensors had good response to alcohol. The response of the gracile nanorods prepared at a low calcined temperature demonstrated significantly better than the thick nanorods prepared at a high calcined temperature. The mechanism was attributed to the nonstoichiometric ratio of Sn/O and larger surface area of the gracile nanorods to enhance the oxygen surface adsorption.

Preparation of ZrO II/nano-TiO II composite powder by sol-gel method

NASA Astrophysics Data System (ADS)

Baharvandi, H. R.; Mohammadi, E.; Abdizadeh, H.; Hadian, A. M.; Ehsani, N.

2007-07-01

The effects of concentration of TTIP, amount of distilled water, and calcination temperature on morphology and particle size distribution of ZrO II/nano-TiO II catalysts were investigated. Mixed ZrO II/nano-TiO II powders were prepared by a modified sol-gel method by varying the mole fraction of TTIP from 0.002 to 0.01, H IIO/TTIP fraction from 2 to 8, and various stirring time (2, 4, and 10 h). The prepared ZrO II/nano-TiO II powders have been characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD), and TG/DTA. Each oxide was calcined at the temperature between 110 and 1000°C. The results showed that the calcinations temperature has a pronounced effect on the phase formation and particle size of the calcined zirconium titanate (ZT) powders.

Photooxidative desulfurization for diesel using Fe / N - TiO2 photocatalyst

NASA Astrophysics Data System (ADS)

Khan, Muhammad Saqib; Kait, Chong Fai; Mutalib, Mohd Ibrahim Abdul

2014-10-01

A series of N - TiO2 with different mol% N was synthesized via sol-gel method and characterized using thermal gravimetric analyzer and raman spectroscopy. 0.2 wt% Fe was incorporated onto the calcined (200°C) N - TiO2 followed by calcination at 200°C, 250°C and 300°C. Photooxidative desulfurization was conducted in the presence of 0.2wt% Fe / N - TiO2 with different mol% N with and without oxidant (H2O2). Oxidative desulfurization was only achieved when H2O2 was used while without H2O2 no major effect on the sulfur removal. 0.2Fe -30N - H2O2 photocatalysts showed best performance at all calcination temperatures as compared to other mol% N - H2O2 photocatalysts. 16.45% sulfur removal was achieved using photocatalysts calcined at 300 °C.

Effect of calcinations temperature of CuO nanoparticle on the kinetics of decontamination and decontamination products of sulphur mustard.

PubMed

Mahato, T H; Singh, Beer; Srivastava, A K; Prasad, G K; Srivastava, A R; Ganesan, K; Vijayaraghavan, R

2011-09-15

Present study investigates the potential of CuO nanoparticles calcined at different temperature for the decontamination of persistent chemical warfare agent sulphur mustard (HD) at room temperature (30 ± 2 °C). Nanoparticles were synthesized by precipitation method and characterized by using SEM, EDAX, XRD, and Raman Spectroscopy. Synthesized nanoparticles were tested as destructive adsorbents for the degradation of HD. Reactions were monitored by GC-FID technique and the reaction products characterized by GC-MS. It was observed that the rate of degradation of HD decreases with the increase in calcination temperature and there is a change in the percentage of product of HD degradation. GC-MS data indicated that the elimination product increases with increase in calcination temperature whereas the hydrolysis product decreases. Copyright © 2011 Elsevier B.V. All rights reserved.

Synthesis of Hydroxyapatite through Ultrasound and Calcination Techniques

NASA Astrophysics Data System (ADS)

Akindoyo, John O.; Beg, M. D. H.; Ghazali, Suriati; Akindoyo, Edward O.; Jeyaratnam, Nitthiyah

2017-05-01

There is a growing demand for hydroxyapatite (HA) especially in medical applications, production of HA which is totally green is however a challenge. In this research, HA was produced from biowaste through ultrasound followed by calcination techniques. Pre-treatment of the biowaste was effectively achieved through the help of ultrasound. After calcination at 950°C, the obtained HA was characterized through Thermogravimetric (TGA) analysis, X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR). Spectrum of the produced HA was compared with standard HA index. The spectrum is in agreement with the standard HA as confirmed through FTIR, XRD and TGA result. Furthermore, morphological study of the HA through Field emission scanning electron microscope (FESEM) shows almost uniform spherical shape for the HA as expected. Based on the results obtained herein, combining ultrasound with calcination can help to produce pure HA with potential medical applications without the use of any organic solvent.

Preparation and optical properties of trivalent europium doped into cordierite using the sol-gel process

NASA Astrophysics Data System (ADS)

Thim, Gilmar P.; Brito, Hermi F.; Silva, Sandra A.; Oliveira, Maria A. S.; Felinto, Maria C. F. C.

2003-02-01

The photoluminescence properties of the Eu3+ ion doped into α-cordierite were studied based on the excitation and emission spectra and lifetime measurements. These samples were prepared by the sol-gel method and calcined by heating the xerogel at different temperatures: 873, 1133, 1223 and 1473 K. X-ray diffraction patterns were used to characterize the luminescent material. The 5D0→7F0 transition of the samples exhibits only one broad peak arising from the inhomogeneous linewidth of the amorphous phase, except for the ceramic material obtained at 1473 K that presents two peaks. Also, in the latter case the luminescence decay lifetime exhibits a bi-exponential fit when excited at 280 nm, corroborating that the Eu3+ ion exists in two sites of symmetry. The experimental intensity parameter Ω2 (10.0×10-20 cm2) indicates a moderately polarizable chemical environment around the Eu3+ ion. The emission spectra of the Mg2Al4Si5O18:Eu3+ samples calcined at 873, 1133 and 1223 K also presented inhomogeneous profiles for the 5D0→7FJ transitions suggesting disorder of the material. On the other hand, the sample calcined at 1473 K shows narrow bands indicating the crystalline form. The emission quantum efficiency (η) of the α-cordierite system is also discussed.

Highly Visible Light Activity of Nitrogen Doped TiO2 Prepared by Sol-Gel Approach

NASA Astrophysics Data System (ADS)

Than, Le Dien; Luong, Ngo Sy; Ngo, Vu Dinh; Tien, Nguyen Manh; Dung, Ta Ngoc; Nghia, Nguyen Manh; Loc, Nguyen Thai; Thu, Vu Thi; Lam, Tran Dai

2017-01-01

A simple approach was explored to prepare N-doped anatase TiO2 nanoparticles (N-TiO2 NPs) from titanium chloride (TiCl4) and ammonia (NH3) via sol-gel method. The effects of important process parameters such as calcination temperatures, NH3/TiCl4 molar ratio ( R N) on crystallite size, structure, phase transformation, and photocatalytic activity of titanium dioxide (TiO2) were thoroughly investigated. The as-prepared samples were characterized by ultraviolet-visible spectroscopy, x-ray diffraction, transmission electron microscopy, energy dispersive x-ray spectroscopy, and x-ray photoelectron spectroscopy. The photocatalytic activity of the samples was evaluated upon the degradation of methylene blue aqueous solution under visible-light irradiation. The results demonstrated that both calcination temperatures and NH3/TiCl4 molar ratios had significant impacts on the formation of crystallite nanostructures, physicochemical, as well as catalytic properties of the obtained TiO2. Under the studied conditions, calcination temperature of 600°C and NH3/TiCl4 molar ratio of 4.2 produced N-TiO2 with the best crystallinity and photocatalytic activity. The high visible light activity of the N-TiO2 nanomaterials was ascribed to the interstitial nitrogen atoms within TiO2 lattice units. These findings could provide a practical pathway capable of large-scale production of a visible light-active N-TiO2 photocatalyst.

Enhanced removal of natural organic matters by calcined Mg/Al layered double hydroxide nanocrystalline particles: Adsorption, reusability and mechanism studies

NASA Astrophysics Data System (ADS)

Fang, Liping; Hou, Jingwei; Xu, Cuihong; Wang, Yaru; Li, Ji; Xiao, Feng; Wang, Dongsheng

2018-06-01

Natural organic matters (NOMs) can generate disinfection by-products during water treatment process, threatening to human health. However, the removal of NOM is still unsatisfactory in water treatment. Hence, this work investigated the removal efficiency of humic and fulvic acids (HA and FA) by layered double hydroxide (LDH) and its calcined forms under different conditions. Our results show that calcination of LDH at 500 °C can effectively enhance the NOM removal with adsorption capacities of 98.8 mg/g for HA and 97.6 mg/g for FA at pH 9.5. The removal efficiency of HA and FA notably increases by decreasing pH. The presence of SO42- and CO32- significantly suppresses the removal of HA or FA by CLDHs. The release of Al from LDH and CLDH is negligible and safe to aquatic organisms at pH > 6.5. Moreover, CLDH shows a good reusability for NOM removal in water treatment. The removal of HA and FA by CLDH is governed through electrostatic interactions and intercalation into the interlayers of LDH was not observed. Fluorescence and molecular weight analyses show that the microbial by-products with mid-molecular weight are more difficult to be removed than HA and FA. This study provides a new insight into the NOM removal using LDH and CLDH.

CaO-based CO2 sorbents: from fundamentals to the development of new, highly effective materials.

PubMed

Kierzkowska, Agnieszka M; Pacciani, Roberta; Müller, Christoph R

2013-07-01

The enormous anthropogenic emission of the greenhouse gas CO2 is most likely the main reason for climate change. Considering the continuing and indeed growing utilisation of fossil fuels for electricity generation and transportation purposes, development and implementation of processes that avoid the associated emissions of CO2 are urgently needed. CO2 capture and storage, commonly termed CCS, would be a possible mid-term solution to reduce the emissions of CO2 into the atmosphere. However, the costs associated with the currently available CO2 capture technology, that is, amine scrubbing, are prohibitively high, thus making the development of new CO2 sorbents a highly important research challenge. Indeed, CaO, readily obtained through the calcination of naturally occurring limestone, has been proposed as an alternative CO2 sorbent that could substantially reduce the costs of CO2 capture. However, one of the major drawbacks of using CaO derived from natural sources is its rapidly decreasing CO2 uptake capacity with repeated carbonation-calcination reactions. Here, we review the current understanding of fundamental aspects of the cyclic carbonation-calcination reactions of CaO such as its reversibility and kinetics. Subsequently, recent attempts to develop synthetic, CaO-based sorbents that possess high and cyclically stable CO2 uptakes are presented. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Feasibility Study of the Geotextile Waste Filtration Unit.

DTIC Science & Technology

2000-02-10

Treatment Module 3-32 Figure 3-20. THE SCHEMATIC OF THE MOVING BED BIOFILM REACTOR ( MBBR ) 3൪ Figure 4-1. The Original Distributed Concept for WFUs...Moving Bed Biofilm Reactor ( MBBR ) process appears to be one of the most feasible processes available to meet Force Provider liquid waste stream...Moving Bed Biofilm Reactor ( MBBR ) process was then examined.31 In this system, both activated sludge and fixed-film processes occur in a bioreactor

Recovery of SO2 and MgO from By-Products of MgO Wet Flue Gas Desulfurization

PubMed Central

Yan, Liyun; Lu, Xiaofeng; Wang, Quanhai; Guo, Qiang

2014-01-01

Abstract An industrial demonstration unit using natural gas as a heat source was built to calcine the by-products of MgO wet flue gas desulfurization from power plants; influencing factors on the SO2 content in calciner gas were comprehensively analyzed; and an advantageous recycling condition of MgO and SO2 from by-products was summarized. Results showed that the SO2 content in the calciner gas was increased by more than 10 times under a lower excess air coefficient, a higher feed rate, a lower crystal water in by-products, and a higher feed port position. For the tests conducted under the excess air coefficient above and below one, the effect of the furnace temperature on the SO2 content in the calciner gas was reversed. Results of activity analysis indicate that particles of MgO generated under the calcination temperature of 900–1,000°C had a high activity. In contrast, due to the slight sintering, MgO generated under the calcination temperature of 1,100°C had a low activity. To recycle SO2 as well as MgO, a temperature range of 900–927°C for TE103 is proposed. These studies will prompt the desulfurization market diversification, reduce the sulfur's dependence on imports for making sulfuric acid, be meaningful to balance the usage of the natural resource in China, and be regarded as a reference for the development of this technology for other similar developing countries. PMID:25371652

IDAHO CHEMICAL PROCESSING PLANT TECHNICAL PROGRESS REPORT FOR APRIL THROUGH JUNE 1958

DOE Office of Scientific and Technical Information (OSTI.GOV)

Stevenson, C.E.

1958-11-01

Processing of uranium -aluminum alloy was continued with slight process modifications. Means for recovering rare gases from dissolver off-gas are described. Results of extensive decontamination procedures required to enable entrance to the continuous dissolver cell are also indicated. Pilot plant studies of dissolving aluminum continuously showed that rates of dissolution were decreased by factors of 2 to 4 as the concentration of nitric acid fed was increased from 5.4 to 11N. The rate of aluminum dissolution was found to be proportional to initial area exposed for pieces of different shape. It was found possible to produce a highly basic aluminummore » nitrate solution at a reasonable rate by dissolving to low concentration in dilute acid, followed by evaporation to the desired level. Uranium exchange rate measurements for the TBP extraction process are described. A canned rotor pump under test with graphite bearings operated 6000 hours with nominal wear. Difficulties were experienced in testing a nutating disc pump. Measurements of the potential of zirconium in hydrofluoric acid as a function of pH confirmed the predicted equation. In teflon vessels, zirconium dissolves a little more rapidly in nitric-hydrofluoric acid mixtures than in glass vessels, presumably due to reaction of fluoride with silica. Titunium alloy Types 55A and 75A were found to resist corrosion by certain boiling nitric-hydrochloric acid mixtures. Initial tests have commenced with a NaK-heated 100 liter/hour pilot plant aluminum nitrate calciner to continue process demonstration. In tests in the smaller pilot plant unit, increasing feed spray air ratio was found to increase particle loading in the cyclone effluent. Laboratory studies indicated that a venturi scrubber using dilute nitric acid at 80 C should remove ruthenium effectively from calciner off-gas. In a pilot plant test in which a significant fraction of ruthenium feed was retained by the alumina, substantial absorption of volatilized ruthenium was obtained. Thermal conductivity of alumina near 3000 F was about 0.26 Btu/hr)(ft)( F). In leaching studies, very little strontium or plutonium was removed by water from alumina calcined at 550 C. Dilute nitric acid, however, extracted strontium from this material to the same degree (~ 50 percent) as from material calcined at 400 C. Concentrated basic aluminum nitrate was produced from simulated aluminum nitrate waste by slow hydrolysis with urea followed by evaporation. Aluminum was efficiently extracted from buffered aluminum nitrate solution by acetylacetone and was stripped back into nitric acid. A filterable aluminum phosphate was precipituted from aluminum nitrate solution by urea hydrolysis; the phosphate effectively carried fission products, however. Spectrophotometric methods were developed for macro and micro quantities of uranium, in the presence of high concentrations of other ions, based on tetrapropylammonium nitrate extraction. (For preceding period see ID0-14443.) (auth)« less

40 CFR 98.82 - GHGs to report.

Code of Federal Regulations, 2014 CFR

2014-07-01

... (General Stationary Fuel Combustion Sources) by following the requirements of subpart C. (d) CO2, CH4, and... GREENHOUSE GAS REPORTING Cement Production § 98.82 GHGs to report. You must report: (a) CO2 process emissions from calcination in each kiln. (b) CO2 combustion emissions from each kiln. (c) CH4 and N2O combustion...

40 CFR 98.82 - GHGs to report.

Code of Federal Regulations, 2013 CFR

2013-07-01

... (General Stationary Fuel Combustion Sources) by following the requirements of subpart C. (d) CO2, CH4, and... GREENHOUSE GAS REPORTING Cement Production § 98.82 GHGs to report. You must report: (a) CO2 process emissions from calcination in each kiln. (b) CO2 combustion emissions from each kiln. (c) CH4 and N2O combustion...

40 CFR 98.82 - GHGs to report.

Code of Federal Regulations, 2012 CFR

2012-07-01

... (General Stationary Fuel Combustion Sources) by following the requirements of subpart C. (d) CO2, CH4, and... GREENHOUSE GAS REPORTING Cement Production § 98.82 GHGs to report. You must report: (a) CO2 process emissions from calcination in each kiln. (b) CO2 combustion emissions from each kiln. (c) CH4 and N2O combustion...

40 CFR Appendix I to Part 265 - Recordkeeping Instructions

Code of Federal Regulations, 2014 CFR

2014-07-01

... T10Infrared furnace incinerator T11Molten salt destructor T12Pyrolysis T13Wet Air oxidation T14Calcination... T21Chemical fixation T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination... Chloride Process Oxidation Reactor T89Methane Reforming Furnace T90Pulping Liquor Recovery Furnace...

40 CFR Appendix I to Part 265 - Recordkeeping Instructions

Code of Federal Regulations, 2011 CFR

2011-07-01

... T10Infrared furnace incinerator T11Molten salt destructor T12Pyrolysis T13Wet Air oxidation T14Calcination... T21Chemical fixation T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination... Chloride Process Oxidation Reactor T89Methane Reforming Furnace T90Pulping Liquor Recovery Furnace...

40 CFR Appendix I to Part 265 - Recordkeeping Instructions

Code of Federal Regulations, 2013 CFR

2013-07-01

... T10Infrared furnace incinerator T11Molten salt destructor T12Pyrolysis T13Wet Air oxidation T14Calcination... T21Chemical fixation T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination... Chloride Process Oxidation Reactor T89Methane Reforming Furnace T90Pulping Liquor Recovery Furnace...

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2011 CFR

2011-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2012 CFR

2012-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2013 CFR

2013-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

40 CFR Appendix I to Part 265 - Recordkeeping Instructions

Code of Federal Regulations, 2012 CFR

2012-07-01

... T10Infrared furnace incinerator T11Molten salt destructor T12Pyrolysis T13Wet Air oxidation T14Calcination... T21Chemical fixation T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination... Chloride Process Oxidation Reactor T89Methane Reforming Furnace T90Pulping Liquor Recovery Furnace...

40 CFR Appendix I to Part 264 - Recordkeeping Instructions

Code of Federal Regulations, 2014 CFR

2014-07-01

... incinerator T11Molten salt destructor T12Pyrolysis T13Wet air oxidation T14Calcination T15Microwave discharge... T22Chemical oxidation T23Chemical precipitation T24Chemical reduction T25Chlorination T26Chlorinolysis... Furnace T87Smelting, Melting, or Refining Furnace T88Titanium Dioxide Chloride Process Oxidation Reactor...

Virtual Design of a 4-Bed Molecular Sieve for Exploration

NASA Technical Reports Server (NTRS)

Giesy, Timothy J.; Coker, Robert F.; O'Connor, Brian F.; Knox, James C.

2017-01-01

Simulations of six new 4-Bed Molecular Sieve configurations have been performed using a COMSOL (COMSOL Multiphysics - commercial software) model. The preliminary results show that reductions in desiccant bed size and sorbent bed size when compared to the International Space Station configuration are feasible while still yielding a process that handles at least 4.0 kilograms a day CO2. The results also show that changes to the CO2 sorbent are likewise feasible. Decreasing the bed sizes was found to have very little negative effect on the adsorption process; breakthrough of CO2 in the sorbent bed was observed for two of the configurations, but a small degree of CO2 breakthrough is acceptable, and water breakthrough in the desiccant beds was not observed. Both configurations for which CO2 breakthrough was observed still yield relatively high CO2 efficiency, and future investigations will focus on bed size in order to find the optimum configuration.

Virtual Design of a 4-Bed Molecular Sieve for Exploration

NASA Technical Reports Server (NTRS)

Giesy, Timothy J.; Coker, Robert F.; O'Connor, Brian F.; Knox, James C.

2017-01-01

Simulations of six new 4-Bed Molecular Sieve configurations have been performed using a COMSOL model. The preliminary results show that reductions in desiccant bed size and sorbent bed size when compared to the International Space Station configuration are feasible while still yielding a process that handles at least 4.0 kg/day CO2. The results also show that changes to the CO2 sorbent are likewise feasible. Decreasing the bed sizes was found to have very little negative effect on the adsorption process; breakthrough of CO2 in the sorbent bed was observed for two of the configurations, but water breakthrough in the desiccant beds was not observed. Nevertheless, both configurations for which CO2 breakthrough was observed still yield relatively high CO2 efficiency, and future investigations will focus on bed size in order to find the optimum configuration.

Preparation, characterization and dye adsorption of Au nanoparticles/ZnAl layered double oxides nanocomposites

NASA Astrophysics Data System (ADS)

Zhang, Yu Xin; Hao, Xiao Dong; Kuang, Min; Zhao, Han; Wen, Zhong Quan

2013-10-01

In this work, Au/ZnAl-layer double oxides (LDO) nanocomposties were prepared through a facile calcination process of AuCl4- intercalated ZnAl-layered double hydroxides (LDHs) nanocomposites. The morphology and crystal structure of these nanocomposites were characterized by Scanning electron microscopy (SEM), transmission electron microscopy (TEM), powder X-ray diffraction (XRD), and N2 sorption analysis. By tailoring the process parameter, such as calcination temperature, heating time and the component composition, the adsorption properties of methyl orange (MO) on the Au/ZnAl-LDO nanocomposites were investigated in this work. In a typical adsorption process, it was found that 0.985 mg of MO (0.01 g L-1, 100 mL, 1 mg of MO in total) can be removed in 60 min by utilizing only 2.5 mg of Au/ZnAl-LDO (Au content, 1%) as adsorbents. Our adsorption data obtained from the Langmuir model also gave good values of the determination coefficient, and the saturated adsorption capacity of Au/ZnAl-LDO nanocomposites for MO was found to be 627.51 mg/g under ambient condition (e.g., room temperature, 1 atm). In principle, these hybrid nanostructures with higher adsorption abilities could be very promising adsorbents for wastewater treatment.

The mechanism of vapor phase hydration of calcium oxide: implications for CO2 capture.

PubMed

Kudłacz, Krzysztof; Rodriguez-Navarro, Carlos

2014-10-21

Lime-based sorbents are used for fuel- and flue-gas capture, thereby representing an economic and effective way to reduce CO2 emissions. Their use involves cyclic carbonation/calcination which results in a significant conversion reduction with increasing number of cycles. To reactivate spent CaO, vapor phase hydration is typically performed. However, little is known about the ultimate mechanism of such a hydration process. Here, we show that the vapor phase hydration of CaO formed after calcination of calcite (CaCO3) single crystals is a pseudomorphic, topotactic process, which progresses via an intermediate disordered phase prior to the final formation of oriented Ca(OH)2 nanocrystals. The strong structural control during this solid-state phase transition implies that the microstructural features of the CaO parent phase predetermine the final structural and physicochemical (reactivity and attrition) features of the product hydroxide. The higher molar volume of the product can create an impervious shell around unreacted CaO, thereby limiting the efficiency of the reactivation process. However, in the case of compact, sintered CaO structures, volume expansion cannot be accommodated in the reduced pore volume, and stress generation leads to pervasive cracking. This favors complete hydration but also detrimental attrition. Implications of these results in carbon capture and storage (CCS) are discussed.

Dispersed-nanoparticle loading synthesis for monodisperse Au-titania composite particles and their crystallization for highly active UV and visible photocatalysts.

PubMed

Sakamoto, Takeshi; Nagao, Daisuke; Noba, Masahiro; Ishii, Haruyuki; Konno, Mikio

2014-06-24

Submicrometer-sized amorphous titania spheres incorporating Au nanoparticles (NPs) were prepared in a one-pot synthesis consisting of a sol-gel reaction of titanium(IV) isopropoxide in the presence of chloroauric acid and a successive reduction with sodium borohydride in a mixed solvent of ethanol/acetonitrile. The synthesis was allowed to prepare monodisperse titania spheres that homogeneously incorporated Au NPs with sizes of ca. 7 nm. The Au NP-loaded titania spheres underwent different crystallization processes, including 500 °C calcination in air, high-temperature hydrothermal treatment (HHT), and/or low-temperature hydrothermal treatment (LHT). Photocatalytic experiments were conducted with the Au NP-loaded crystalline titania spheres under irradiation of UV and visible light. A combined process of LHT at 80 °C followed by calcination at 500 °C could effectively crystallize titania spheres maintaining the dispersion state of Au NPs, which led to photocatalytic activity higher than that of commercial P25 under UV irradiation. Under visible light irradiation, the Au NP-titania spheres prepared with a crystallization process of LHT at 80 °C for 6 h showed photocatalytic activity much higher than a commercial product of visible light photocatalyst. Structure analysis of the visible light photocatalysts indicates the importance of prevention of the Au NPs aggregation in the crystallization processes for enhancement of photocatalytic activity.

Facile synthesis and microwave absorbability of C@Ni–NiO core–shell hybrid solid sphere and multi-shelled NiO hollow sphere

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wu, Hongjing, E-mail: wuhongjing@mail.nwpu.edu.cn; Wu, Guanglei, E-mail: wuguanglei@mail.xjtu.edu.cn; Wu, Qiaofeng

2014-11-15

We reported the preparation of C@Ni–NiO core–shell hybrid solid spheres or multi-shelled NiO hollow spheres by combining a facile hydrothermal route with a calcination process in H{sub 2} or air atmosphere, respectively. The synthesized C@Ni–NiO core–shell solid spheres with diameters of approximately 2–6 μm were in fact built from dense NiO nanoparticles coated by random two-dimensional metal Ni nanosheets without any visible pores. The multi-shelled NiO hollow spheres were built from particle-like ligaments and there are a lot of pores with size of several nanometers on the surface. Combined Raman spectra with X-ray photoelectron spectra (XPS), it suggested that themore » defects in the samples play a limited role in the dielectric loss. Compared with the other samples, the permeability of the samples calcined in H{sub 2} and air was increased slightly and the natural resonance frequency shifted to higher frequency (7, 11 and 14 GHz, respectively), leading to an enhancement of microwave absorption property. For the sample calcined in H{sub 2}, an optimal reflection loss less than − 10 was obtained at 7 GHz with a matching thickness of 5.0 mm. Our study demonstrated the potential application of C@Ni–NiO core–shell hybrid solid sphere or multi-shelled NiO hollow sphere as a more efficient electromagnetic (EM) wave absorber. - Highlights: • C@Ni–NiO core–shell hybrid solid sphere was synthesized by a facile method. • Multi-shelled NiO hollow sphere was synthesized by a facile method. • It suggested that the defects in the samples play a limited role in dielectric loss. • The permeability of the samples calcined in H{sub 2} and air was increased. • Microwave absorbability of C@Ni–NiO core–shell hybrid solid sphere was investigated.« less

Preparation and properties of calcium oxide from eggshells via calcination

NASA Astrophysics Data System (ADS)

Tangboriboon, N.; Kunanuruksapong, R.; Sirivat, A.

2012-12-01

Duck eggs are one of the most versatile cooking ingredients in which residue eggshells are discarded. Raw duck eggshells were calcined at temperatures between 300 to 900 °C, for 1, 3, and 5 h. Both the raw and calcined duck eggshells were characterized by FTIR, STA, XRD, XRF, TEM, BET, a particle size analyzer, and an impedance analyzer. The proper calcination conditions are: 900 °C and 1 h, yielding calcium oxide with a purity of 99.06 % w/w. The calcium carbonate of the rhombohedral form (CaCO3) transforms completely into the calcium oxide or lime of the face centered cubic form (CaO) at 900 °C, as shown by XRD diffraction patterns. The transmission electron microscopy (TEM) images of the calcium oxide reveal a moderately good dispersion of nearly uniform particles. The calcium oxide has a white color, a spherical shape, high porosity, and narrow particles size distribution. The percentage of ceramic yield of the calcium oxide is 53.53, as measured by STA (TG-DTA-DTG). The calcium oxide has a N2 adsorption-desorption isotherm indicating the meso-porosity range. The dielectric constant and the electrical conductivity of the calcined calcium oxide are 35 and 1:0×10-6(Ω·m)-1, respectively, at the frequency of 500 Hz.

Effect of sulfuric acid concentration of bentonite and calcination time of pillared bentonite

NASA Astrophysics Data System (ADS)

Mara, Ady; Wijaya, Karna; Trisunaryati, Wega; Mudasir

2016-04-01

An activation of natural clay has been developed. Activation was applied by refluxing the natural bentonite in variation of the sulfuric acid concentration and calcination time of pillared bentonite (PLC). Calcination was applied using oven in microwave 2,45 GHz. Determination of acidity was applied by measuring the amount of adsorbed ammonia and pyridine. Morphological, functional groups and chrystanility characterizations were analyzed using SEM, TEM, FTIR and XRD. Porosity was analyzed using SSA. The results showed that the greater of the concentration of sulfuric acid and calcination time was, the greater the acidity of bentonite as well as the pore diameter were. FTIR spectra showed no fundamental changes in the structure of the natural bentonite, SEM, and TEM images were showing an increase in space or field due to pillarization while the XRD patterns showed a shift to a lower peak. Optimization was obtained at a concentration of 2 M of sulfuric acid and calcination time of 20 minutes, keggin ion of 2.2 and suspension of 10 mmol, respectively each amounted to 11.7490 mmol/gram of ammonia and 2.4437 mmol/gram of pyridine with 154.6391 m2/gram for surface area, 0.130470 m3/gram of pore volume and 3.37484 nm of pore diameter.

Effect of fly ash calcination in geopolymer synthesis

NASA Astrophysics Data System (ADS)

Samadhi, Tjokorde Walmiki; Jatiningrum, Mirna; Arisiani, Gresia

2015-12-01

Geopolymer, a largely amorphous class of inorganic polymer consisting of aluminosilicate repeat units, is an environmentally attractive engineering material due to its ability to consume aluminosilicate waste as raw materials. This work studies the effect of the calcination temperature of a coal fly ash generated by a low-efficiency boiler on the mechanical strength of geopolymer mortar synthesized using a mixture of the fly ash, potassium hydroxide as the alkali activator, and locally available sand as the filler aggregate. The calcination temperature is varied between 500-700 °C, with a calcination period of 2 hours in an electric furnace. Two sand samples with different particle size distributions are used. The key response variable is the compressive strength at room temperature, measured after curing at 80 °C for 7 and 14 days. Uncalcined ash, with a carbon content of approximately 31.0%, is not amenable for geopolymer synthesis. Analysis of experimental data using the ANOVA method for general factorial design identifies significant main effects for all three experimental variables. Two-way interactions are significant, except that between sand type and curing period. Higher calcination temperature significantly improves the strength of the mortar. However, the strength of the obtained geopolymer mortars are still significantly lower than that of ordinary Portland cement mortar.

Fluidized bed gasification of industrial solid recovered fuels.

PubMed

Arena, Umberto; Di Gregorio, Fabrizio

2016-04-01

The study evaluates the technical feasibility of the fluidized bed gasification of three solid recovered fuels (SRFs), obtained as co-products of a recycling process. The SRFs were pelletized and fed to a pilot scale bubbling fluidized bed reactor, operated in gasification and co-gasification mode. The tests were carried out under conditions of thermal and chemical steady state, with a bed of olivine particles and at different values of equivalence ratio. The results provide a complete syngas characterization, in terms of its heating value and composition (including tars, particulates, and acid/basic pollutants) and of the chemical and physical characterization of bed material and entrained fines collected at the cyclone outlet. The feasibility of the fluidized bed gasification process of the different SRFs was evaluated with the support of a material and substance flow analysis, and a feedstock energy analysis. The results confirm the flexibility of fluidized bed reactor, which makes it one of the preferable technologies for the gasification of different kind of wastes, even in co-gasification mode. The fluidized bed gasification process of the tested SRFs appears technically feasible, yielding a syngas of valuable quality for energy applications in an appropriate plant configuration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Updraft Fixed Bed Gasification Aspen Plus Model

DOE Office of Scientific and Technical Information (OSTI.GOV)

2007-09-27

The updraft fixed bed gasification model provides predictive modeling capabilities for updraft fixed bed gasifiers, when devolatilization data is available. The fixed bed model is constructed using Aspen Plus, process modeling software, coupled with a FORTRAN user kinetic subroutine. Current updraft gasification models created in Aspen Plus have limited predictive capabilities and must be "tuned" to reflect a generalized gas composition as specified in literature or by the gasifier manufacturer. This limits the applicability of the process model.

Composition and process for making an insulating refractory material

DOEpatents

Pearson, A.; Swansiger, T.G.

1998-04-28

A composition and process are disclosed for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4--2.6 g/cm{sup 3} with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness.

Method and apparatus for a combination moving bed thermal treatment reactor and moving bed filter

DOEpatents

Badger, Phillip C.; Dunn, Jr., Kenneth J.

2015-09-01

A moving bed gasification/thermal treatment reactor includes a geometry in which moving bed reactor particles serve as both a moving bed filter and a heat carrier to provide thermal energy for thermal treatment reactions, such that the moving bed filter and the heat carrier are one and the same to remove solid particulates or droplets generated by thermal treatment processes or injected into the moving bed filter from other sources.

Three-dimensional rotation electron diffraction: software RED for automated data collection and data processing

PubMed Central

Wan, Wei; Sun, Junliang; Su, Jie; Hovmöller, Sven; Zou, Xiaodong

2013-01-01

Implementation of a computer program package for automated collection and processing of rotation electron diffraction (RED) data is described. The software package contains two computer programs: RED data collection and RED data processing. The RED data collection program controls the transmission electron microscope and the camera. Electron beam tilts at a fine step (0.05–0.20°) are combined with goniometer tilts at a coarse step (2.0–3.0°) around a common tilt axis, which allows a fine relative tilt to be achieved between the electron beam and the crystal in a large tilt range. An electron diffraction (ED) frame is collected at each combination of beam tilt and goniometer tilt. The RED data processing program processes three-dimensional ED data generated by the RED data collection program or by other approaches. It includes shift correction of the ED frames, peak hunting for diffraction spots in individual ED frames and identification of these diffraction spots as reflections in three dimensions. Unit-cell parameters are determined from the positions of reflections in three-dimensional reciprocal space. All reflections are indexed, and finally a list with hkl indices and intensities is output. The data processing program also includes a visualizer to view and analyse three-dimensional reciprocal lattices reconstructed from the ED frames. Details of the implementation are described. Data collection and data processing with the software RED are demonstrated using a calcined zeolite sample, silicalite-1. The structure of the calcined silicalite-1, with 72 unique atoms, could be solved from the RED data by routine direct methods. PMID:24282334

Three-dimensional rotation electron diffraction: software RED for automated data collection and data processing.

PubMed

Wan, Wei; Sun, Junliang; Su, Jie; Hovmöller, Sven; Zou, Xiaodong

2013-12-01

Implementation of a computer program package for automated collection and processing of rotation electron diffraction (RED) data is described. The software package contains two computer programs: RED data collection and RED data processing. The RED data collection program controls the transmission electron microscope and the camera. Electron beam tilts at a fine step (0.05-0.20°) are combined with goniometer tilts at a coarse step (2.0-3.0°) around a common tilt axis, which allows a fine relative tilt to be achieved between the electron beam and the crystal in a large tilt range. An electron diffraction (ED) frame is collected at each combination of beam tilt and goniometer tilt. The RED data processing program processes three-dimensional ED data generated by the RED data collection program or by other approaches. It includes shift correction of the ED frames, peak hunting for diffraction spots in individual ED frames and identification of these diffraction spots as reflections in three dimensions. Unit-cell parameters are determined from the positions of reflections in three-dimensional reciprocal space. All reflections are indexed, and finally a list with hkl indices and intensities is output. The data processing program also includes a visualizer to view and analyse three-dimensional reciprocal lattices reconstructed from the ED frames. Details of the implementation are described. Data collection and data processing with the software RED are demonstrated using a calcined zeolite sample, silicalite-1. The structure of the calcined silicalite-1, with 72 unique atoms, could be solved from the RED data by routine direct methods.

Mercury isotope fractionation during ore retorting in the Almadén mining district, Spain

USGS Publications Warehouse

Gray, John E.; Pribil, Michael J.; Higueras, Pablo L.

2013-01-01

Almadén, Spain, is the world's largest mercury (Hg) mining district, which has produced over 250,000 metric tons of Hg representing about 30% of the historical Hg produced worldwide. The objective of this study was to measure Hg isotopic compositions of cinnabar ore, mine waste calcine (retorted ore), elemental Hg (Hg0(L)), and elemental Hg gas (Hg0(g)), to evaluate potential Hg isotopic fractionation. Almadén cinnabar ore δ202Hg varied from − 0.92 to 0.15‰ (mean of − 0.56‰, σ = 0.35‰, n = 7), whereas calcine was isotopically heavier and δ202Hg ranged from − 0.03‰ to 1.01‰ (mean of 0.43‰, σ = 0.44‰, n = 8). The average δ202Hg enrichment of 0.99‰ between cinnabar ore and calcines generated during ore retorting indicated Hg isotopic mass dependent fractionation (MDF). Mass independent fractionation (MIF) was not observed in any of the samples in this study. Laboratory retorting experiments of cinnabar also were carried out to evaluate Hg isotopic fractionation of products generated during retorting such as calcine, Hg0(L), and Hg0(g). Calcine and Hg0(L) generated during these retorting experiments showed an enrichment in δ202Hg of as much as 1.90‰ and 0.67‰, respectively, compared to the original cinnabar ore. The δ202Hg for Hg0(g) generated during the retorting experiments was as much as 1.16‰ isotopically lighter compared to cinnabar, thus, when cinnabar ore was roasted, the resultant calcines formed were isotopically heavier, whereas the Hg0(g) generated was isotopically lighter in Hg isotopes.

Preparation of LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphors by a facile precursor method and their luminescent properties

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Xia; Liang, Pan; Huang, Hong-Sheng

2014-04-01

Graphical abstract: LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor was obtained by calcining the precursor which was synthesized by boric acid melting method. It (a) exhibits much stronger PL intensity than that (b) prepared by conventional solid state reaction method. - Highlights: • A calcining precursor method was used for preparation of LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor. • Precursor was prepared by boric acid melting method. • The luminescence intensity of LaB{sub 3}O{sub 6}:Eu{sup 3+} was enhanced by the present method. - Abstract: The LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphors were prepared by calcining the precursors which were synthesized by boric acid meltingmore » method using rare earth oxide and boric acid as raw materials, and they were characterized by EDS, XRD, IR, SEM and PL. The influences of reaction temperature for the preparation of precursor and subsequent calcination temperature and time of precursor on the luminescence properties of LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor were investigated. The results showed that the LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphors with maximum luminescent intensity were obtained by calcining precursor at 1000 °C for 6 h, in which the precursor was prepared at 200 °C for 72 h. Compared with the conventional high temperature solid-state reaction method, the pure LaB{sub 3}O{sub 6}:Eu{sup 3+} phosphor can be obtained at relatively lower calcination temperature by the precursor method and exhibits much stronger emission intensity.« less

Effect of TiO2 calcination temperature on the photocatalytic oxidation of gaseous NH3.

PubMed

Wu, Hongmin; Ma, Jinzhu; Zhang, Changbin; He, Hong

2014-03-01

Carbon-modified titanium dioxide (TiO2) was prepared by a sol-gel method using tetrabutyl titanate as precursor, with calcination at various temperatures, and tested for the photocatalytic oxidation (PCO) of gaseous NH3 under visible and UV light. The test results showed that no samples had visible light activity, while the TiO2 calcined at 400°C had the best UV light activity among the series of catalysts, and was even much better than the commercial catalyst P25. The catalysts were then characterized by X-ray diffractometry, Brunauer-Emmett-Teller adsorption analysis, Raman spectroscopy, thermogravimetry/differential scanning calorimetry coupled with mass spectrometry, ultraviolet-visible diffuse reflectance spectra, photoluminescence spectroscopy and in situ diffuse reflectance infrared Fourier transform spectroscopy. It was shown that the carbon species residuals on the catalyst surfaces induced the visible light adsorption of the samples calcined in the low temperature range (< 300°C). However, the surface acid sites played a determining role in the PCO of NH3 under visible and UV light over the series of catalysts. Although the samples calcined at low temperatures had very high SSA, good crystallinity, strong visible light absorption and also low PL emission intensity, they showed very low PCO activity due to their very low number of acid sites for NH3 adsorption and activation. The TiO2 sample calcined at 400°C contained the highest number of acid sites among the series of catalysts, therefore showing the highest performance for the PCO of NH3 under UV light. Copyright © 2014 The Research Centre for Eco-Environmental Sciences, Chinese Academy of Sciences. Published by Elsevier B.V. All rights reserved.

Mercury and methylmercury contents in mine-waste calcine, water, and sediment collected from the Palawan Quicksilver mine, Philippines

USGS Publications Warehouse

Gray, J.E.; Greaves, I.A.; Bustos, D.M.; Krabbenhoft, D.P.

2003-01-01

The Palawan Quicksilver mine, Philippines, produced about 2,900 t of mercury during mining of cinnabar ore from 1953 to 1976. More than 2,000,000 t of mine-waste calcines (retorted ore) were produced during mining, much of which were used to construct a jetty in nearby Honda Bay. Since 1995, high Hg contents have been found in several people living near the mine, and 21 of these people were treated for mercury poisoning. Samples of mine-waste calcine contain high total Hg concentrations ranging from 43-660 ??g/g, whereas total Hg concentrations in sediment samples collected from a mine pit lake and local stream vary from 3.7-400 ??g/g. Mine water flowing through the calcines is acidic, pH 3.1-4.3, and total Hg concentrations ranging from 18-31 ??g/l in this water significantly exceed the 1.0-??g/l drinking water standard for Hg recommended by the World Health Organization (WHO). Total Hg contents are generally lower in water samples collected from surrounding domestic wells, the mine pit lake, Honda Bay, and the nearby stream, varying from 0.008-1.4 ??g/l. Methylmercury concentrations in water draining mine calcines range from <0.02-1.4 ng/l, but methylmercury is highest in the pit lake water, ranging from 1.7-3.1 ng/l. Mercury methylation at the Palawan mine is similar to or higher than that found in other mercury mines worldwide. Much of the methylmercury generated in Palawan mine-waste calcines and those in Honda Bay is transferred to water, and then to marine fish and seafood. A food source pathway of Hg to humans is most likely in this coastal, high fish-consuming population.

Bed load transport in gravel-bed rivers

Treesearch

Jeffrey J. Barry

2007-01-01

Bed load transport is a fundamental physical process in alluvial rivers, building and maintaining a channel geometry that reflects both the quantity and timing of water and the volume and caliber of sediment delivered from the watershed. A variety of formulae have been developed to predict bed load transport in gravel-bed rivers, but testing of the equations in natural...

Research on acting mechanism and behavior of a gas bubble in the air dense medium fluidized bed

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tao, X.; Chen, Q.; Yang, Y.

1996-12-31

Coal dry beneficiation with air-dense medium fluidized bed has now been established as a high efficiency dry separation technology, it is the application of fluidization technology to the coal preparation field. The tiny particle media forms an uniform and stable fluidized bed with a density acted by airflow, which is used to separate 80{micro}m to {approximately}6mm size coal. This technology has achieved satisfied industrialization results, and attracted the expert`s attention in the field. In fluidized bed, the interaction between gas and solid was mainly decided by the existence state of heavy media particles mass (position and distance) relative velocity ofmore » gas-solid two phase, as well turbulent action. A change of vertical gas-solid fluidizing state essentially is the one of a energy transforming process. For a coal separating process with air-dense medium fluidized bed, the gas bubble, producing a turbulent and stirring action in the bed, leads to two effects. It can promote a uniform distribution of heavy media particles, and a uniform and stability of a bed density. Otherwise it will decrease effective contacts between gas-solids two phases, producing a bigger gas bubble. Therefore controlling a gas bubble size in bed should be optimized. This paper analyzes mutual movement between gas-solid, and studies the gas bubble behavior in the bed. A mechanic mode and a separating process of coal in the bed is discussed. It aims to research the coal separating mechanism with air-dense fluidized bed.« less

Method for producing refractory nitrides

DOEpatents

Quinby, Thomas C.

1989-01-24

A process for making fine, uniform metal nitride powders that can be hot pressed or sintered. A metal salt is placed in a solvent with Melamine and warmed until a metal-Melamine compound forms. The solution is cooled and the metal-Melamine precipitate is calcined at a temperature below 700.degree. C. to form the metal nitrides and to avoid formation of the metal oxide.

Americium recovery from reduction residues

DOEpatents

Conner, W.V.; Proctor, S.G.

1973-12-25

A process for separation and recovery of americium values from container or bomb'' reduction residues comprising dissolving the residues in a suitable acid, adjusting the hydrogen ion concentration to a desired level by adding a base, precipitating the americium as americium oxalate by adding oxalic acid, digesting the solution, separating the precipitate, and thereafter calcining the americium oxalate precipitate to form americium oxide. (Official Gazette)

Ultrafine manganese dioxide nanowire network for high-performance supercapacitors.

PubMed

Jiang, Hao; Zhao, Ting; Ma, Jan; Yan, Chaoyi; Li, Chunzhong

2011-01-28

Ultrafine MnO(2) nanowires with sub-10 nm diameters have been synthesized by a simple process of hydrothermal treatment with subsequent calcinations to form networks that exhibit an enhanced specific capacitance (279 F g(-1) at 1 A g(-1)), high rate capability (54.5% retention at 20 A g(-1)) and good cycling stability (1.7% loss after 1000 cycles).

12. PHOTOGRAPH OF A PHOTOGRAPH OF A SCALE MODEL OF ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

12. PHOTOGRAPH OF A PHOTOGRAPH OF A SCALE MODEL OF THE WASTE CALCINER FACILITY, SHOWING WEST ELEVATION. (THE ORIGINAL MODEL HAS BEEN LOST.) INEEL PHOTO NUMBER 95-903-1-3. - Idaho National Engineering Laboratory, Old Waste Calcining Facility, Scoville, Butte County, ID

Hydrogen production from carbonaceous material

DOEpatents

Lackner, Klaus S.; Ziock, Hans J.; Harrison, Douglas P.

2004-09-14

Hydrogen is produced from solid or liquid carbon-containing fuels in a two-step process. The fuel is gasified with hydrogen in a hydrogenation reaction to produce a methane-rich gaseous reaction product, which is then reacted with water and calcium oxide in a hydrogen production and carbonation reaction to produce hydrogen and calcium carbonate. The calcium carbonate may be continuously removed from the hydrogen production and carbonation reaction zone and calcined to regenerate calcium oxide, which may be reintroduced into the hydrogen production and carbonation reaction zone. Hydrogen produced in the hydrogen production and carbonation reaction is more than sufficient both to provide the energy necessary for the calcination reaction and also to sustain the hydrogenation of the coal in the gasification reaction. The excess hydrogen is available for energy production or other purposes. Substantially all of the carbon introduced as fuel ultimately emerges from the invention process in a stream of substantially pure carbon dioxide. The water necessary for the hydrogen production and carbonation reaction may be introduced into both the gasification and hydrogen production and carbonation reactions, and allocated so as transfer the exothermic heat of reaction of the gasification reaction to the endothermic hydrogen production and carbonation reaction.

Effect of microwave-assisted sintering on dielectric properties of CaCu{sub 3}Ti{sub 4}O{sub 12} ceramic

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rani, Suman, E-mail: sumanranigju@gmail.com; Ahlawat, Neetu; Punia, R.

2016-05-23

In this present work, CaCu{sub 3}Ti{sub 4}O{sub 12} (CCTO) was synthesized by conventional solid-state reaction technique. The synthesis process was carried out in two phases; by conventional process (calcination and sintering at 1080°C for 10 hours) and phase II involves the micro assisted pre sintering of conventionally calcined CCTO for very short soaking time of 30 min at 1080°C in a microwave furnace followed by sintering at 1080°C for 10 hours in conventional furnace. X-ray diffraction (XRD) patterns confirmed the formation of single phase ceramic. Dielectric properties were studied over the frequency range from 50Hz -5MHz at temperatures (273K-343K). It wasmore » observed that pre- microwave sintering enhance the dielectric constant values from 10900 to 11893 and respectively reduces the dielectric loss values from 0.49 to 0.34 at room temperature(1 KHz). CCTO ceramics which are found desirable for many technological applications. The effect is more pronounced at low frequencies of applied electric field.« less

Ceramic-like open-celled geopolymer foam as a porous substrate for water treatment catalyst

NASA Astrophysics Data System (ADS)

Kovářík, T.; Křenek, T.; Pola, M.; Rieger, D.; Kadlec, J.; Franče, P.

2017-02-01

This paper presents results from experimental study on microstructural and mechanical properties of geopolymer-based foam filters. The process for making porous ceramic-like geopolymer body was experimentally established, consists of (a) geopolymer paste synthesis, (b) ceramic filler incorporation, (c) coating of open-celled polyurethane foam with geopolymer mixture, (d) rapid setting procedure, (e) thermal treatment. Geopolymer paste was based on potassium silicate solution n(SiO2)/n(K2O)=1.6 and powder mixture of calcined kaolin and precipitated silica. Various types of ceramic granular filler (alumina, calcined schistous clay and cordierite) were tested in relation to aggregate gradation design and particle size distribution. The small amplitude oscillatory rheometry in strain controlled regime 0.01% with angular frequency 10 rad/s was applied for determination of rheology behavior of prepared mixtures. Thermal treatment conditions were applied in the temperature range 1100 - 1300 °C. The developed porous ceramic-like foam effectively served as a substrate for highly active nanoparticles of selected Fe+2 spinels. Such new-type of nanocomposite was tested as a heterogeneous catalyst for technological process of advanced oxidative degradation of resistive antibiotics occurring in waste waters.

Biodiesel synthesis using calcined layered double hydroxide catalysts

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schumaker, J. Link; Crofcheck, Czarena; TAckett, S. Adam

2008-01-01

The catalytic properties of calcined Li-Al, Mg-Al and Mg-Fe layered double hydroxides (LDHs) were examined in two transesterification reactions, namely, the reaction of glyceryl tributyrate with methanol, and the reaction of soybean oil with methanol. While the Li-Al catalysts showed high activity in these reactions at the reflux temperature of methanol, the Mg-Fe and Mg-Al catalysts exhibited much lower methyl ester yields. CO2 TPD measurements revealed the presence of sites of weak, medium and strong basicity on both Mg-Al and Li-Al catalysts, the latter showing higher concentrations of medium and strong base sites; by implication, these are the main sitesmore » active in transesterification catalyzed by calcined Li-Al LDHs. Maximum activity was observed for the Li-Al catalysts when a calcination temperature of 450-500 aC was applied, corresponding to decomposition of the layered double hydroxide to the mixed oxide without formation of crystalline lithium aluminate phases.« less

Bismuth doping effect on crystal structure and photodegradation activity of Bi-TiO2 nanoparticles

NASA Astrophysics Data System (ADS)

Wu, Ming-Chung; Chang, Yin-Hsuan; Lin, Ting-Han

2017-04-01

The bismuth precursor is adopted as dopant to synthesize bismuth doped titanium dioxide nanoparticles (Bi-TiO2 NPs) with sol-gel method following by the thermal annealing treatment. We systematically developed a series of Bi-TiO2 NPs at several calcination temperatures and discovered the corresponding crystal structure by varying the bismuth doping concentration. At a certain 650 °C calcination temperature, the crystal structure of bismuth titanate (Bi2Ti2O7) is formed when the bismuth doping concentration is as high as 10.0 mol %. The photocatalytic activity of Bi-TiO2 NPs is increased by varying the doping concentration at the particular calcination temperature. By the definition X-ray diffraction (XRD) structural identification, a phase diagram of Bi-TiO2 NPs in doping concentration versus calcination temperature is provided. It can be useful for further study in the crystal structure engineering and the development of photocatalyst.

Calcined Eggshell Waste for Mitigating Soil Antibiotic-Resistant Bacteria/Antibiotic Resistance Gene Dissemination and Accumulation in Bell Pepper.

PubMed

Ye, Mao; Sun, Mingming; Feng, Yanfang; Li, Xu; Schwab, Arthur P; Wan, Jinzhong; Liu, Manqiang; Tian, Da; Liu, Kuan; Wu, Jun; Jiang, Xin

2016-07-13

The combined accumulation of antibiotics, heavy metals, antibiotic-resistant bacteria (ARB)/antibiotic resistance genes (ARGs) in vegetables has become a new threat to human health. This is the first study to investigate the feasibility of calcined eggshells modified by aluminum sulfate as novel agricultural wastes to impede mixed contaminants from transferring to bell pepper (Capsicum annuum L.). In this work, calcined eggshell amendment mitigated mixed pollutant accumulation in bell pepper significantly, enhanced the dissipation of soil tetracycline, sulfadiazine, roxithromycin, and chloramphenicol, decreased the water-soluble fractions of antibiotics, and declined the diversity of ARB/ARGs inside the vegetable. Moreover, quantitative polymerase chain reaction analysis detected that ARG levels in the bell pepper fruits significantly decreased to 10(-10) copies/16S copies, indicating limited risk of ARGs transferring along the food chain. Furthermore, the restoration of soil microbial biological function suggests that calcined eggshell is an environmentally friendly amendment to control the dissemination of soil ARB/ARGs in the soil-vegetable system.

(Bi, Pb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x} superconductor and method of making same utilizing sinter-forging

DOEpatents

Chen, N.; Goretta, K.C.; Lanagan, M.T.

1998-10-13

A (BiPb){sub 2}Sr{sub 2}Ca{sub 2}Cu{sub 3}O{sub x}(Bi223) superconductor with high J{sub c}, phase purity, density and mechanical strength is formed from Bi2223 powder which is synthesized from a mixture of Bi{sub 2}O{sub 3}, PbO, SrCO{sub 3}, CaCo{sub 3} and CuO. The mixture is milled, then dried and calcined to synthesize the Bi2223 powder with the desired phase purity. The calcination is performed by heating the dried mixture for 50 hours at 840 C. The partially synthesized powder is then milled for 1--4 hours before calcining further for another 50 hours at 855 C to complete the synthesis. After calcination, the Bi2223 powder is cold pressed to a predetermined density and sinter forged under controlled temperature and time to form a Bi2223 superconductor with the desired superconducting properties. 5 figs.

(Bi, Pb).sub.2, Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x superconductor and method of making same utilizing sinter-forging

DOEpatents

Chen, Nan; Goretta, Kenneth C.; Lanagan, Michael T.

1998-01-01

A (BiPb).sub.2 Sr.sub.2 Ca.sub.2 Cu.sub.3 O.sub.x (Bi223) superconductor with high J.sub.c, phase purity, density and mechanical strength is formed from Bi2223 powder which is synthesized from a mixture of Bi.sub.2 O.sub.3, PbO, SrCO.sub.3, CaCo.sub.3 and CuO. The mixture is milled, then dried and calcined to synthesize the Bi2223 powder with the desired phase purity. The calcination is performed by heating the dried mixture for 50 hours at 840.degree. C. The partially synthesized powder is then milled for 1-4 hours before calcining further for another 50 hours at 855.degree. C. to complete the synthesis. After calcination, the Bi2223 powder is cold pressed to a predetermined density and sinter forged under controlled temperature and time to form a Bi2223 superconductor with the desired superconducting properties.

Electrochemical performance of LiV3O8 micro-rod at various calcination temperatures as cathode materials for lithium ion batteries

NASA Astrophysics Data System (ADS)

Noerochim, Lukman; Ginanjar, Edith Setia; Susanti, Diah; Prihandoko, Bambang

2018-04-01

Lithium vanadium oxide (LiV3O8) has been successfully synthesized by hydrothermal method followed by calcination via the reaction of Lithium hydroxide (LiOH) and ammonium metavanade (NH4VO3). The precursors were heated at hydrothermal at 200 °C and then calcined at different calcination temperature in 400, 450, and 500 °C. The characterization by X-ray diffraction (XRD) and scanning electron microscope (SEM) is indicated that LiV3O8 micro-rod have been obtained by this method. The cyclic voltammetry (CV) result showed that redox reaction occur in potential range between 2.42 - 3.57 V for the reduction reaction and oxidation reaction in potential range between 2.01 V-3.69 V. The highest result was obtained for sample 450 °C with specific discharge capacity of 138 mA/g. The result showed that LiV3O8 has a promising candidate as a cathode material for lithium ion batteries.

Statistical description of flume experiments on mixed-size bed-load transport and bed armoring processes

NASA Astrophysics Data System (ADS)

Chen, D.; Zhang, Y.

2008-12-01

The objective of this paper is to describe the statistical properties of experiments on non-uniform bed-load transport as well as the mechanism of bed armoring processes. Despite substantial effort made over the last two decades, the ability to compute the bed-load flux in a turbulent system remains poor. The major obstacles include the poor understanding of the formation of armor lays on bed surfaces. Such a layer is much flow-resistible than the underlying material and therefore significantly inhibits sediment transport from the reach. To study the problem, we conducted a flume study for mixed sand/gravel sediments. We observed that aggregated sediment blocks were the most common characters in armor layers - the largest sizes resist hydraulic forces, while the smaller sizes add interlocking support and prevent loss of fine material through gaps between the larger particles. Fractional transport rates with the existing of armor layers were measured with time by sediment trapping method at the end of flume. To address the intermittent and time-varying behavior of bed-load transport during bed armoring processes, we investigated the probability distribution of the fractional bed-load transport rates, and the underlying dynamic model derived from the continuous time random walk framework. Results indicate that it is critical to consider the impact of armor layers when a flow is sufficient to move some of the finer particles and yet insufficient to move all the larger particles on a channel bed.

Hydrothermal synthesis and influence of later heat treatment on the structural evolution, optical and electrical properties of nanostructured α-MoO3 single crystals

NASA Astrophysics Data System (ADS)

Badr, A. M.; El-Anssary, E. H.; Elshaikh, H. A.; Afify, H. H.

2017-12-01

In the current study, α-MoO3 nanocrystals were successfully synthesized from ammonium heptamolybdate tetrahydrate using a simple hydrothermal route. The influence of calcination temperature on the structural, optical and electrical properties was systematically investigated for the MoO3 powder products. The XRD results were analyzed for these powders, revealing the formation of a mixed phase (β- and α-MoO3) at calcination temperatures ranging from 350 °C-450 °C, and hence a residual monoclinic phase still exists in the samples at the calcination temperature of 450 °C. Subsequently, the mixed phase was completely converted to a pure single phase of α-MoO3 at a calcination temperature of 500 °C. The optical properties of the MoO3 powders were investigated using the transformed diffuse reflectance technique according to Kubelka-Munk theory. For such a powder product, the results of the optical measurements demonstrated the realization of indirect and direct allowed transitions at the spectral ranges 3.31-3.91 eV and 3.66-4.27 eV, respectively. The indirect- and direct-allowed band-gaps of the MoO3 products were found to increase from 2.69-3.12 eV and from 3.43-3.64 eV, respectively, by increasing the calcination temperature from 350 °C-600 °C. The MoO3 powders calcined at different temperatures were converted into five dense tablets for performing the electrical measurements. These measurements were carried out at different working temperatures using a system operating under high vacuum conditions. The results revealed that the dc-conductivity of such a tablet typically increases by more than five orders of magnitude with an increase in the working temperature from 77-300 K. These results also demonstrated a high dependence of dc-conductivity on the calcination temperature for the MoO3 products. The dc-conductivity as a function of the operating temperature revealed the presence of at least three different electrical conduction mechanisms for the same MoO3 tablet.

Refractory concentrate gold leaching: Cyanide vs. bromine

NASA Astrophysics Data System (ADS)

Dadgar, Ahmad

1989-12-01

Gold extraction, recovery and economics for two refractory concentrates were investigated using cyanide and bromine reagents. Gold extractions for cyanide leaching (24-48 hours) and bromine leaching (six hours) were the same and ranged from 94 to 96%. Gold recoveries from bromine pregnant solutions using carbon adsorption, ion exchange, solvent extraction, and zinc and aluminum precipitation methods were better than 99.9%. A preliminary economic analysis indicates that chemical costs for cyanidation and bromine process are 11.70 and 11.60 respectively, per tonne of calcine processed.

Heat pump apparatus

DOEpatents

Nelson, Paul A.; Horowitz, Jeffrey S.

1983-01-01

A heat pump apparatus including a compact arrangement of individual tubular reactors containing hydride-dehydride beds in opposite end sections, each pair of beds in each reactor being operable by sequential and coordinated treatment with a plurality of heat transfer fluids in a plurality of processing stages, and first and second valves located adjacent the reactor end sections with rotatable members having multiple ports and associated portions for separating the hydride beds at each of the end sections into groups and for simultaneously directing a plurality of heat transfer fluids to the different groups. As heat is being generated by a group of beds, others are being regenerated so that heat is continuously available for space heating. As each of the processing stages is completed for a hydride bed or group of beds, each valve member is rotated causing the heat transfer fluid for the heat processing stage to be directed to that bed or group of beds. Each of the end sections are arranged to form a closed perimeter and the valve member may be rotated repeatedly about the perimeter to provide a continuous operation. Both valves are driven by a common motor to provide a coordinated treatment of beds in the same reactors. The heat pump apparatus is particularly suitable for the utilization of thermal energy supplied by solar collectors and concentrators but may be used with any source of heat, including a source of low-grade heat.

Influence of thermally activated paper sludge on the behaviour of blended cements subjected to saline and non-saline environments.

PubMed

García, Rosario; Rubio, Virginia; Vegas, Iñigo; Frías, Moisés

2009-05-01

One of the problems to affect Portland cement matrices is low resistance to aggressive agents, due principally to the presence of a high content of portlandite in the hydrated cements. Pozzolanic materials have played an important role in the improving the durability of cement-based materials for decades. This work studies the behaviour of cement mortar matrices blended with 10% calcined paper sludge (source for metakaolinite) and exposed to different environmental conditions (saline and non-saline environments) after 6 and 12 months of exposure. Two cements were studied: an ordinary Portland cement (CEM 1, 42.5R), acting as reference cement, and a blended cement formulated by mixing 90% (by mass) of CEM 1, 42.5R with 10% (by mass) of paper sludge calcined at 700 degrees C for 2 h. The specimens were exposed 1 year to saline and non-saline environments. All the mineralogy samples were studied through X-ray diffraction and scanning electron microscopy (SEM) equipped with an energy dispersive X-ray analyser. The in-depth study on ionic mobility was performed on samples subjected to natural exposure (coast and tableland) for 6 and 12 months. Portland cement was composed of quartz, calcite, calcium hydroxide and tobermorite gels. The pozzolanic cement (10% calcined paper sludge) is of the same composition but a high calcite concentration and barium carbonate. SEM analysis from coastline show deposits of variable composition. The deposits are identified on the surface of different mineral components. The minerals from tableland are much fractured, i.e. calcite and feldspars. Inside the fractures, the deposits and the ions are located and trapped superficially. SEM analysis of control cement Portland and 10% calcined paper sludge shows deposits on quartz and calcite with a very high concentration of Pb, Zn, Cl and barium sulphate. A very porous aspect is due to the presence of the different aggregate types. This porous configuration permits retention of the ion environment. The pozzolanic cement in environments subject to the saline mist favours the retention and transport of ions observed. Something similar also happens with the increase in exposure to outdoor weather. Non-saline samples show temperature changes (ice or thaw cycles). Barium retention is kept on the surface in fracture lines by the gelification processes. In general, it may be inferred that an increase in exposure time increases the diffusion of ions towards test piece interiors. The chemical composition profiles show that the ions present different penetration speeds. The results indicate the better vulnerability of pozzolanic cements from calcined paper sludge in saline and non-saline environments. The cements with a 10% addition of calcined paper sludge favour retention and transport of ion has been observed. Today, projects are centred on a new recycling line for industrial waste of this kind, with special attention on its incorporation in cement manufacture as a pozzolanic material, setting the most appropriate activation conditions of the mineralogical compound in this waste (kaolinite and metakaolinite) and taking them as a starting point for this project. The use of pozzolanic cement with 10% addition of calcined paper sludge is a system which favours ionic retention.

In vitro cytotoxicity and quantitative silica analysis of diatomaceous earth products.

PubMed

Bye, E; Davies, R; Griffiths, D M; Gylseth, B; Moncrieff, C B

1984-05-01

Mouse peritoneal macrophages were used to evaluate the relative cytotoxicity of a series of diatomaceous earth products in vitro. The amorphous and crystalline silica content of the products was determined by a combination of infrared spectroscopy and x ray powder diffraction techniques. The cytotoxicities of the high cristobalite content flux calcined materials were similar to that of the standard cristobalite ; both the natural and straight calcined materials had significantly greater activities than the flux calcined materials. Thus within the limitations of the macrophage cytotoxicity test the hypothesis that crystalline content is the only determinant of fibrogenicity of diatomaceous earth is not supported.

In vitro cytotoxicity and quantitative silica analysis of diatomaceous earth products.

PubMed Central

Bye, E; Davies, R; Griffiths, D M; Gylseth, B; Moncrieff, C B

1984-01-01

Mouse peritoneal macrophages were used to evaluate the relative cytotoxicity of a series of diatomaceous earth products in vitro. The amorphous and crystalline silica content of the products was determined by a combination of infrared spectroscopy and x ray powder diffraction techniques. The cytotoxicities of the high cristobalite content flux calcined materials were similar to that of the standard cristobalite ; both the natural and straight calcined materials had significantly greater activities than the flux calcined materials. Thus within the limitations of the macrophage cytotoxicity test the hypothesis that crystalline content is the only determinant of fibrogenicity of diatomaceous earth is not supported. Images PMID:6326795

Effect of different alcohols, gelatinizing times, calcination and microwave on characteristics of TiO2 nanoparticles synthesized by sol-gel method

NASA Astrophysics Data System (ADS)

Bahar, Mahmoud; Mozaffari, Masoud; Esmaeili, Sahar

2017-03-01

In this work, nanoparticles of titanium dioxide (TiO2) were synthesized by means of TiCl4 as precursor. Effects of alcohol type, calcination, gelatinizing time and microwave exposure on the particle size, morphology, crystallinity and particle phase are studied using XRD patterns and SEM images. Results showed that alcohols such as ethanol increased the particle size; calcination increased the particle size and improved the crystallinity of particles. Microwave exposure of particles resulted in smaller particles; adding water increased the impact of microwave. Effect of microwave exposure in rutile phase formation is also observed during this study.

Heat and mass transfer within partially wetted packed fractured granular beds

DOE Office of Scientific and Technical Information (OSTI.GOV)

Khalil, E.B.; Karim, G.A.

1996-10-01

Fractured granular beds heated by hot gaseous streams have been the subject of numerous investigations in recent years due to their importance in many applications such as in in-situ and enhanced oil recovery. In a previous paper (Khalil and Karim, 1995) the results of an investigation of some aspects of the transport processes that occur within dry granular beds were reported. The present contribution examines similar beds when partially wetted. The granular beds were cylindrical in shape containing an axial central small diameter circular channel representing a fracture which can have different permeability from that of the main bed. Itmore » is shown that the mass flow rate of the hot gases, the relative permeability of the bed and the central channel as well as the initial liquid content of the bed control the drying rate. The results of an analytical model formulated to simulate the drying process in unobstructed channel beds showed good agreement with experimental results at low temperatures, however deviations occurred as the drying proceeds at higher temperatures.« less

Enhancement of the sulfur capture capacity of limestones by the addition of Na2CO3 and NaCl.

PubMed

Laursen, K; Grace, J R; Lim, C J

2001-11-01

The ability of Na2CO3 and NaCl to enhance the sulfur capture capacity of three limestones was evaluated via fixed-bed calcination and sulfation experiments. The tested limestones represent three different sulfation morphologies: unreacted-core, network, and uniformly sulfated. Treatment with aqueous or powdered Na2CO3 significantly increased the Ca-utilization for two stones which normally sulfate in an unreacted-core pattern (20% to 45%) and network pattern (33% to 49%). The increase was lower for the uniformly sulfated stone (44% to 48%). Na2CO3 treatment increased the number of macropores leading to uniform sulfation of all particles, nearly eliminating the normal strong dependence of utilization on limestone type and particle size. The effect of Na2CO3 is believed to be associated with formation of a eutectic melt which enhances ionic diffusion and accelerates molecular rearrangement of the CaO. Treatment with aqueous NaCl solution caused a decrease in utilization, probably due to formation of large grains and plugging of pores caused by formation of a large amount of eutectic melt. The effect of Na2CO3 is less sensitive than that of NaCl to the amount added and the combustion environment (temperature and gas composition). In addition, Na2CO3 neither promotes corrosion nor forms chlorinated byproducts, which are main concerns associated with NaCl. Thus, Na2CO3 appears to have significant advantages over NaCl for enhancement of limestone sulfur capture capacity in fluidized-bed combustors.

Nitrogen cycling processes and microbial community composition in bed sediments in the Yukon River at Pilot Station

USGS Publications Warehouse

Repert, Deborah A.; Underwood, Jennifer C.; Smith, Richard L.; Song, Bongkeun

2014-01-01

Information on the contribution of nitrogen (N)-cycling processes in bed sediments to river nutrient fluxes in large northern latitude river systems is limited. This study examined the relationship between N-cycling processes in bed sediments and N speciation and loading in the Yukon River near its mouth at the Bering Sea. We conducted laboratory bioassays to measure N-cycling processes in sediment samples collected over distinct water cycle seasons. In conjunction, the microbial community composition in the bed sediments using genes involved in N-cycling (narG, napA, nosZ, and amoA) and 16S rRNA gene pyrosequences was examined. Temporal variation was observed in net N mineralization, nitrate uptake, and denitrification rate potentials and correlated strongly with sediment carbon (C) and extractable N content and microbial community composition rather than with river water nutrient concentrations. The C content of the bed sediment was notably impacted by the spring flood, ranging from 1.1% in the midst of an ice-jam to 0.1% immediately after ice-out, suggesting a buildup of organic material (OM) prior to scouring of the bed sediments during ice break up. The dominant members of the microbial community that explained differences in N-processing rates belonged to the genera Crenothrix,Flavobacterium, and the family of Comamonadaceae. Our results suggest that biogeochemical processing rates in the bed sediments appear to be more coupled to hydrology, nutrient availability in the sediments, and microbial community composition rather than river nutrient concentrations at Pilot Station.

Cements for Structural Concrete in Cold Regions.

DTIC Science & Technology

1977-10-01

ability to reduce the early evolu- tion of heat: slag and obsidian, pumicite and calcined shale, fly-ash , tuff and calcined diatomite , natural cement...and uncalcined diatomite . Variations in initial set times of cements can be controlled ‘cy varying the percentages of different cement mixtures . Wh it

Incorporation of polyoxotungstate complexes in silica spheres and in situ formation of tungsten trioxide nanoparticles.

PubMed

Zhao, Yuanyuan; Fan, Haimei; Li, Wen; Bi, Lihua; Wang, Dejun; Wu, Lixin

2010-09-21

In this paper, we demonstrated a new convenient route for in situ fabrication of well separated small sized WO(3) nanoparticles in silica spheres, through a predeposition of surfactant encapsulated polyoxotungates as tungsten source, and followed by a calcination process. In a typical procedure, selected polyoxotungates with different charges were enwrapped with dioctadecyldimethylammonium cations through electrostatic interaction. Elemental analysis, thermogravimetric analysis, and spectral characterization confirmed the formation of prepared complexes with the anticipated chemical structure. The complexes were then phase-transferred into aqueous solution that predissolved surfactant cetyltrimethylammonium bromide, and finally incorporated into silica spheres through a joint sol-gel reaction with tetraethyl orthosilicate in a well dispersed state under the protection of organic layer for polyoxotungates from the alkaline reaction condition. Transmission electron microscopic images illustrated the well dispersed WO(3) nanoparticles in the size range of ca. 2.2 nm in the silica spheres after the calcination at 465 °C. The sizes of both the silica spheres and WO(3) nanoparticles could be adjusted independently through changing the doping content to a large extent. Meanwhile, the doped polyoxotungate complexes acted as the template for the mesoporous structure in silica spheres after the calcination. Along with the increase of doping content and surfactant, the mesopore size changed little (2.0-2.9 nm), but the specific surface areas increased quite a lot. Importantly, the WO(3)-nanoparticle-doped silica spheres displayed an interesting photovoltaic property, which is favorable for the funtionalization of these nanomaterials.

Synthesis of highly efficient α-Fe{sub 2}O{sub 3} catalysts for CO oxidation derived from MIL-100(Fe)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cui, Lifeng; Zhao, Di; Yang, Yang

Mesoporous hollow α-Fe{sub 2}O{sub 3} bricks were synthesized via a hydrothermal method to create a precursor MIL-100(Fe) and a subsequent calcination process was applied to prepare the Fe{sub 2}O{sub 3} phase. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) results showed the morphology of hollow α-Fe{sub 2}O{sub 3} bricks which inherited from the MIL-100(Fe) template. The catalytic activities of hollow α-Fe{sub 2}O{sub 3} bricks for CO oxidation are studied in this work. Due to better low temperature reduction behavior, mesoporous hollow α-Fe{sub 2}O{sub 3} bricks obtained at calcination temperature of 430 °C displayed high catalytic activity and excellent stabilitymore » with a complete CO conversion temperature (T{sub 100}) of 255 °C. - Graphical abstract: Synthesis of highly efficient α-Fe{sub 2}O{sub 3} catalysts for CO oxidation derived from MIL-100(Fe). - Highlights: • α-Fe{sub 2}O{sub 3} is prepared by the thermolysis of a MIL-100(Fe) template. • The morphology of hollow α-Fe{sub 2}O{sub 3} bricks is inherited from MIL-100(Fe) template. • α-Fe{sub 2}O{sub 3} obtained at calcined temperature of 430 °C displays high activity • Enhanced activity is attributed to crystal plane and reduction behavior.« less

Quantifying Morphological Features of α-U3O8 with Image Analysis for Nuclear Forensics.

PubMed

Olsen, Adam M; Richards, Bryony; Schwerdt, Ian; Heffernan, Sean; Lusk, Robert; Smith, Braxton; Jurrus, Elizabeth; Ruggiero, Christy; McDonald, Luther W

2017-03-07

Morphological changes in U 3 O 8 based on calcination temperature have been quantified enabling a morphological feature to serve as a signature of processing history in nuclear forensics. Five separate calcination temperatures were used to synthesize α-U 3 O 8 , and each sample was characterized using powder X-ray diffraction (p-XRD) and scanning electron microscopy (SEM). The p-XRD spectra were used to evaluate the purity of the synthesized U-oxide; the morphological analysis for materials (MAMA) software was utilized to quantitatively characterize the particle shape and size as indicated by the SEM images. Analysis comparing the particle attributes, such as particle area at each of the temperatures, was completed using the Kolmogorov-Smirnov two sample test (K-S test). These results illustrate a distinct statistical difference between each calcination temperature. To provide a framework for forensic analysis of an unknown sample, the sample distributions at each temperature were compared to randomly selected distributions (100, 250, 500, and 750 particles) from each synthesized temperature to determine if they were statistically different. It was found that 750 particles were required to differentiate between all of the synthesized temperatures with a confidence interval of 99.0%. Results from this study provide the first quantitative morphological study of U-oxides, and reveals the potential strength of morphological particle analysis in nuclear forensics by providing a framework for a more rapid characterization of interdicted uranium oxide samples.

Understanding the effect of surface/bulk defects on the photocatalytic activity of TiO2: anatase versus rutile.

PubMed

Yan, Junqing; Wu, Guangjun; Guan, Naijia; Li, Landong; Li, Zhuoxin; Cao, Xingzhong

2013-07-14

The sole effect of surface/bulk defects of TiO2 samples on their photocatalytic activity was investigated. Nano-sized anatase and rutile TiO2 were prepared by hydrothermal method and their surface/bulk defects were adjusted simply by calcination at different temperatures, i.e. 400-700 °C. High temperature calcinations induced the growth of crystalline sizes and a decrease in the surface areas, while the crystalline phase and the exposed facets were kept unchanged during calcination, as indicated by the characterization results from XRD, Raman, nitrogen adsorption-desorption, TEM and UV-Vis spectra. The existence of surface/bulk defects in calcined TiO2 samples was confirmed by photoluminescence and XPS spectra, and the surface/bulk defect ratio was quantitatively analyzed according to positron annihilation results. The photocatalytic activity of calcined TiO2 samples was evaluated in the photocatalytic reforming of methanol and the photocatalytic oxidation of α-phenethyl alcohol. Based on the characterization and catalytic results, a direct correlation between the surface specific photocatalytic activity and the surface/bulk defect density ratio could be drawn for both anatase TiO2 and rutile TiO2. The surface defects of TiO2, i.e. oxygen vacancy clusters, could promote the separation of electron-hole pairs under irradiation, and therefore, enhance the activity during photocatalytic reaction.

Effect of calcination environments and plasma treatment on structural, optical and electrical properties of FTO transparent thin films

NASA Astrophysics Data System (ADS)

Kafle, Madhav; Kapadi, Ramesh K.; Joshi, Leela Pradhan; Rajbhandari, Armila; Subedi, Deepak P.; Gyawali, Gobinda; Lee, Soo W.; Adhikari, Rajendra; Kafle, Bhim P.

2017-07-01

The dependence of the structural, optical and electrical properties of the FTO thin films on the film thickness (276 nm - 546 nm), calcination environment, and low temperature plasma treatment were examined. The FTO thin films, prepared by spray pyrolysis, were calcinated under air followed by either further heat treatment under N2 gas or treatment in low temperature atmospheric plasma. The samples before and after calcination under N2, and plasma treatment will be represented by Sair, SN2 and SPl, respectively, hereafter. The thin films were characterized by measuring the XRD spectra, SEM images, optical transmittance and reflectance, and sheet resistance of the films before and after calcination in N2 environment or plasma treatment. The presence of sharp and narrow multiple peaks in XRD spectra hint us that the films were highly crystalline (polycrystalline). The samples Sair with the thickness of 471 nm showed as high as 92 % transmittance in the visible range. Moreover, from the tauc plot, the optical bandgap Eg values of the Sair found to be noticeably lower than that of the samples SN2. Very surprisingly, the electrical sheet resistance (Rsh) found to decrease following the trend as Rshair > RshN2 > RshPl. The samples exposed to plasma found to possess the lowest RshPl (for film with thickness 546 nm, the RshPl was 17 Ω /sq.).

Fluidized bed coal desulfurization

NASA Technical Reports Server (NTRS)

Ravindram, M.

1983-01-01

Laboratory scale experiments were conducted on two high volatile bituminous coals in a bench scale batch fluidized bed reactor. Chemical pretreatment and posttreatment of coals were tried as a means of enhancing desulfurization. Sequential chlorination and dechlorination cum hydrodesulfurization under modest conditions relative to the water slurry process were found to result in substantial sulfur reductions of about 80%. Sulfur forms as well as proximate and ultimate analyses of the processed coals are included. These studies indicate that a fluidized bed reactor process has considerable potential for being developed into a simple and economic process for coal desulfurization.

Method and apparatus for enhancing the desulfurization of hot coal gas in a fluid-bed coal gasifier

DOEpatents

Grindley, T.

1988-04-05

A process and apparatus for providing additional desulfurization of the hot gas produced in a fluid-bed coal gasifier, within the gasifier is described. A fluid-bed of iron oxide is located inside the gasifier above the gasification bed in a fluid-bed coal gasifier in which in-bed desulfurization by lime/limestone takes place. The product gases leave the gasification bed typically at 1600 to 1800 F and are partially quenched with water to 1000 to 1200 F before entering the iron oxide bed. The iron oxide bed provides additional desulfurization beyond that provided by the lime /limestone. 1 fig.

Method for enhancing the desulfurization of hot coal gas in a fluid-bed coal gasifier

DOEpatents

Grindley, Thomas

1989-01-01

A process and apparatus for providing additional desulfurization of the hot gas produced in a fluid-bed coal gasifier, within the gasifier. A fluid-bed of iron oxide is located inside the gasifier above the gasification bed in a fluid-bed coal gasifier in which in-bed desulfurization by lime/limestone takes place. The product gases leave the gasification bed typically at 1600.degree. to 1800.degree. F. and are partially quenched with water to 1000.degree. to 1200.degree. F. before entering the iron oxide bed. The iron oxide bed provides additional desulfurization beyond that provided by the lime/limestone.

Transport of nanoparticles with dispersant through biofilm coated drinking water sand filters.

PubMed

Li, Zhen; Aly Hassan, Ashraf; Sahle-Demessie, Endalkachew; Sorial, George A

2013-11-01

This article characterizes, experimentally and theoretically, the transport and retention of engineered nanoparticles (NP) through sand filters at drinking water treatment plants (DWTPs) under realistic conditions. The transport of four commonly used NPs (ZnO, CeO2, TiO2, and Ag, with bare surfaces and coating agents) through filter beds filled with sands from either acid washed and calcined, freshly acquired filter media, and used filter media from active filter media, were investigated. The study was conducted using water obtained upstream of the sand filter at DWTP. The results have shown that capping agents have a determinant importance in the colloidal stability and transport of NPs through the different filter media. The presence of the biofilm in used filter media increased adsorption of NPs but its effects in retaining capped NPs was less significant. The data was used to build a mathematical model based on the advection-dispersion equation. The model was used to simulate the performance of a scale-up sand filter and the effects on filtration cycle of traditional sand filtration system used in DWTPs. Published by Elsevier Ltd.

Attrition Resistant Fischer-Tropsch Catalysts Based on FCC Supports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adeyiga, Adeyinka

2010-02-05

Commercial spent fluid catalytic cracking (FCC) catalysts provided by Engelhard and Albemarle were used as supports for Fe-based catalysts with the goal of improving the attrition resistance of typical F-T catalysts. Catalysts with the Ruhrchemie composition (100 Fe/5 Cu/4.2 K/25 spent FCC on mass basis) were prepared by wet impregnation. XRD and XANES analysis showed the presence of Fe{sub 2}O{sub 3} in calcined catalysts. FeC{sub x} and Fe{sub 3}O{sub 4} were present in the activated catalysts. The metal composition of the catalysts was analyzed by ICP-MS. F-T activity of the catalysts activated in situ in CO at the same conditionsmore » as used prior to the attrition tests was measured using a fixed bed reactor at T = 573 K, P = 1.38 MPa and H{sub 2}:CO ratio of 0.67. Cu and K promoted Fe supported over Engelhard provided spent FCC catalyst shows relatively good attrition resistance (8.2 wt% fines lost), high CO conversion (81%) and C{sub 5}+ hydrocarbons selectivity (18.3%).« less

An efficient TiO2 coated immobilized system for the degradation studies of herbicide isoproturon: durability studies.

PubMed

Verma, A; Prakash, N T; Toor, A P

2014-08-01

The investigation presents the observations on the use of cement beads for the immobilization of TiO2 for the degradation of herbicide isoproturon. The immobilized system was effective in degrading and mineralizing the herbicide for continuous thirty cycles without losing its durability. Catalyst was characterized by SEM-EDAX for checking the durability of the catalyst. The degradation rate followed first order kinetics as measured by change in absorption intensity in UV range as well as HPLC analysis. Two rounds of TiO2 coating on inert cement beads with average diameter 1.5cm at UV Intensity 25Wm(-2) calcined at 400°C were the optimized conditions for the degradation of herbicide isoproturon. More than 90% TOC and COD reduction along with ammonium ions generation (80%) confirmed the mineralization of isoproturon. Fixed bed baffled reactor studies under solar irradiations using the TiO2 immobilized beads confirmed 85% degradation after 6h. LC-MS studies confirmed the intermediates formation and their subsequent degradation using immobilized system. Copyright © 2014 Elsevier Ltd. All rights reserved.

A preliminary study on the reduction of limonite ore by using rice husk as a reducing agent

NASA Astrophysics Data System (ADS)

Maksum, Ahmad; Husein, Michael Kelvin E.; Permana, Sulaksana; Rustandi, Andi; Wahyuadi Soedarsono, Johny

2018-03-01

The abundant of rice husk in Indonesia has encouraged researchers to study the feasibility of rice husk for substituting material that is more expensive or dangerous. In previous study, silica with a purity of 99.9% has been obtained from rice husk with calcinations process. Nevertheless, the gases resulting from the process were not used and left useless. Therefore, in this study, those gases derived from rice husk calcinations process were used as reducing agents during the ferronickel (Fe-Ni) production through a direct reduction process. The objective of this study was to investigate the effect of the amount of rice husk in the pellets on the increase of nickel content in the limonite reduction process. The limonite ore were crushed to the size of less than 150 mesh using disc-mill, and then were mixed with rice husk powder (10, 20, 30 in wt % mass) before being pelletized using bentonite as a binder. The resulted pellets were roasted at 500°C for 60 minutes and then quenched in water media. After drying process, the reduction process of 40g pellets was conducted at 1000°C for 90 minutes with 20g rice husk in furnace. The effects of additional rice husk on the direct reduction of limonite ore pellets were qualitatively analyzed by using X-ray powder diffraction (XRD) and quantitatively by Atomic absorption spectroscopy (AAS). Both analysis results showed that the reduction process followed the reaction scheme: Fe2O3→Fe3O4→FeO and NiO phase was detected in the sample with 20% rice husk addition. The optimum concentration of Ni 1.23% was obtained for 20% rice husk addition.

Dual fluidized bed design for the fast pyrolysis of biomass

USDA-ARS?s Scientific Manuscript database

A mechanism for the transport of solids between fluidised beds in dual fluidised bed systems for the fast pyrolysis of biomass process was selected. This mechanism makes use of an overflow standpipe to transport solids from the fluidised bed used for the combustion reactions to a second fluidised be...

Transient Combustion in Granular Propellant Beds. Part I. Theoretical Modeling and Numerical Solution of Transient Combustion Processes in Mobile Granular Propellant Beds

DTIC Science & Technology

1977-08-01

TR~ANSIENT COMBUSTION PROCESSES IN MOBILE GRANULAR PROPELLANT BEDS Prqprid by The Pennsylvania Stats UnIversiV 197 Dopartme of Nmchanica! EngwineerIng...the ignition and flame spreadinb prc-eases by assuming that the granular propillents are fixed in space; and 3) modeling cf mobile granular beds so...through an aggrtgate of mobile "’actin&, partic~vi. The diffevewsoa Wi derivation of conservation equa~tions betvewu our approacit md this -f a Aivorain

Processes for washing a spent ion exchange bed and for treating biomass-derived pyrolysis oil, and apparatuses for treating biomass-derived pyrolysis oil

DOE Office of Scientific and Technical Information (OSTI.GOV)

Baird, Lance Awender; Brandvold, Timothy A.

Processes and apparatuses for washing a spent ion exchange bed and for treating biomass-derived pyrolysis oil are provided herein. An exemplary process for washing a spent ion exchange bed employed in purification of biomass-derived pyrolysis oil includes the step of providing a ion-depleted pyrolysis oil stream having an original oxygen content. The ion-depleted pyrolysis oil stream is partially hydrotreated to reduce the oxygen content thereof, thereby producing a partially hydrotreated pyrolysis oil stream having a residual oxygen content that is less than the original oxygen content. At least a portion of the partially hydrotreated pyrolysis oil stream is passed throughmore » the spent ion exchange bed. Water is passed through the spent ion exchange bed after passing at least the portion of the partially hydrotreated pyrolysis oil stream therethrough.« less

Synthesis and characterization of nanostructured strontium hexaferrite thin films by the sol-gel method

NASA Astrophysics Data System (ADS)

Masoudpanah, S. M.; Seyyed Ebrahimi, S. A.

2012-07-01

Nanostructured single phase strontium hexaferrite, SrFe12O19, thin films have been synthesized on the (100) silicon substrate using a spin coating sol-gel process. The thin films with various Fe/Sr molar ratios of 8-12 were calcined at different temperatures from 500 to 900 °C. The composition, microstructure and magnetic properties of the SrFe12O19 thin films were characterized using Fourier transform infrared spectroscopy, differential thermal analysis, thermogravimetry, X-ray diffraction, electron microscopy and vibrating sample magnetometer. The results showed that the optimum molar ratio for Fe/Sr was 10 at which the lowest calcination temperature to obtain the single phase strontium hexaferrite thin film was 800 °C. The magnetic measurements revealed that the sample with Fe/Sr molar ratio of 10, exhibited higher saturation magnetization (267.5 emu/cm3) and coercivity (4290 Oe) in comparison with those synthesized under other Fe/Sr molar ratios.

Integrated Utilization of Sewage Sludge and Coal Gangue for Cement Clinker Products: Promoting Tricalcium Silicate Formation and Trace Elements Immobilization

PubMed Central

Yang, Zhenzhou; Zhang, Yingyi; Liu, Lili; Seetharaman, Seshadri; Wang, Xidong; Zhang, Zuotai

2016-01-01

The present study firstly proposed a method of integrated utilization of sewage sludge (SS) and coal gangue (CG), two waste products, for cement clinker products with the aim of heat recovery and environment protection. The results demonstrated that the incremental amounts of SS and CG addition was favorable for the formation of tricalcium silicate (C3S) during the calcinations, but excess amount of SS addition could cause the impediment effect on C3S formation. Furthermore, it was also observed that the C3S polymorphs showed the transition from rhombohedral to monoclinic structure as SS addition was increased to 15 wt %. During the calcinations, most of trace elements could be immobilized especially Zn and cannot be easily leached out. Given the encouraging results in the present study, the co-process of sewage sludge and coal gangue in the cement kiln can be expected with a higher quality of cement products and minimum pollution to the environment. PMID:28773400

Synthesis of YAG nanopowder by the co-precipitation method: Influence of pH and study of the reaction mechanisms

NASA Astrophysics Data System (ADS)

Marlot, Caroline; Barraud, Elodie; Le Gallet, Sophie; Eichhorn, Marc; Bernard, Frédéric

2012-07-01

YAG nanopowders with an average grain size of 30 nm have been successfully synthesized by the co-precipitation method using nitrates with precipitant of ammonium hydrogen carbonate. The influence of precipitation conditions such as pH, aging time and calcination temperature on the formation of secondary phases has been studied. The accurate control of pH value at every stage of precipitation process is crucial to avoid the presence of YAM (Yttrium Aluminium Monoclinic, Y4Al2O9) and yttrium oxide (Y2O3) after calcination. The reaction mechanisms have been investigated using different techniques such as infrared spectroscopy, x-ray diffraction and thermal analyses. The YAG phase is formed around 1050 °C passing through an intermediate phase called YAP (Yttrium Aluminium Perovskite, YAlO3). Local chemical heterogeneities are responsible for the deviation of the Y:Al ratio and the formation of YAP during heat treatment.

Direct fabrication of /sup 238/PuO/sub 2/ fuel forms

DOE Office of Scientific and Technical Information (OSTI.GOV)

Burney, G.A.; Congdon, J.W.

1982-07-01

The current process for the fabrication of /sup 238/PuO/sub 2/ heat sources includes precipitation of small particle plutonium oxalate crystals (4 to 6 ..mu..m diameter), a calcination to PuO/sub 2/, ball milling, cold pressing, granulation (60 to 125 ..mu..m), and granule sintering prior to hot pressing the fuel pellet. A new two-step direct-strike Pu(III) oxalate precipitation method which yields mainly large well-developed rosettes (50 to 100 ..mu..m diameter) has been demonstrated in the laboratory and in the plant. These large rosettes are formed by agglomeration of small (2 to 4 ..mu..m) crystals, and after calcining and sintering, were directly hotmore » pressed into fuel forms, thus eliminating several of the powder conditioning steps. Conditions for direct hot pressing of the large heat-treated rosettes were determined and a full-scale General Purpose Heat Source pellet was fabricated. The pellet had the desired granule-type microstructure to provide dimensional stability at high temperature. 27 figures.« less

Gold Leaching Characteristics and Intensification of a High S and As-Bearing Gold Concentrate

NASA Astrophysics Data System (ADS)

Yang, Yong-bin; Liu, Xiao-liang; Jiang, Tao; Li, Qian; Xu, Bin; Zhang, Yan

Some high sulfur and arsenic-bearing gold concentrate has a gold leaching rate less than 80% by oxidation roasting-pickling-cyanidation process. The characteristics and intensification of gold leaching were studied systemically. By combining chemical composition and phase analysis, the low gold leaching rate was found to lie in the capsulation of gold by iron-containing phases including iron oxides, arsenopyrite and pyrite. 96.66% of gold in the industrial leaching residue was capsulated and 95.88% of the capsulated turned out to be in the iron-containing phases. The results of laboratory pickling-cyanidation experiments on the calcine and industrial leaching residue presented further demonstration for the fact that gold capsulated in the iron-containing phases was hard to be leached. However, the gold cyanide leaching rate of calcine could be raised over 95% by a reduction roasting-pickling pretreatment which played such a significant role in exposing the capsulated gold that gold leaching was intensified remarkably.

Thermal characteristic of limonite ore upon calcination and reduction

NASA Astrophysics Data System (ADS)

Febriana, Eni; Manaf, Azwar; Prasetyo, A. B.; Mayangsari, W.

2018-05-01

Thermal characteristics of the limonite laterite ore types have been studied using TG / DTA. There are four endothermic peaks at 250, 646, 900, and 1023 °C with a total mass loss of 10.07wt%. These four peaks correspond to the XRD results on samples calcined at 600-1000 °C. Analysis of TG / DTA to the mixture of limonite and graphite showed two endothermic reaction peaks at 641 and 900 °C and an exothermic peak at 1180 °C. Reduction of the limonite-graphite mixture was done by heating at 800-1100 °C for 1 hour, and the reduced samples were analyzed using XRD. The results indicate that the reduction process proceed completely at higher temperatures, indicated by the increasing intensity of kamacite and Fe metal phase, and the decrease of peak intensity of carbon due to reaction with metal oxides. At 1100 °C, intensity of Fe-metal decreased due to sintering of Fe which may occur because the temperature was too high.

Practical method of CO.sub.2 sequestration

DOEpatents

Goswami, D Yogi [Gainesville, FL; Lee, Man Su [Houston, TX; Kothurkar, Nikhil K [Tampa, FL; Stefanakos, Elias K [Tampa, FL

2011-03-01

A process and device to capture of CO.sub.2 at its originating source, such as a power plant, is disclosed. Absorbent material is recharged by desorbing CO.sub.2, so that it may be sequestered or used in another application. Continual recharging results in loss of absorbent surface area, due to pore plugging and sintering of particles. Calcium oxide or calcium hydroxide was immobilized to a fibrous ceramic-based fabric substrate as a thin film and sintered, creating an absorbent material. The samples were characterized, showing continuous cyclic carbonation conversions between about 62% and 75% under mild calcination conditions at 750.degree. C. and no CO.sub.2 in N.sub.2. Under the more severe calcination condition at 850.degree. C. and 20 wt % CO.sub.2 in N.sub.2, yttria fabric was superior to alumina as a substrate for carbon dioxide capture and the reactivity of the calcium oxide absorbent immobilized to yttria was maintained at the same level in the 12 cycles.

Utilization of waste of coal-mining enterprise in production of building materials

NASA Astrophysics Data System (ADS)

Chugunov, A. D.; Filatova, E. G.; Yakovleva, A. A.

2018-03-01

Wastes of coal producers often include substances allowing treating such wastes as valuable feeds for metallurgy, chemical and construction processes. This study concerned elemental and phase composition of samples obtained by calcination of bottom sediments of the coal producer spoil bank. The research has shown that the samples contain significant amounts of carbon, iron, silicon, aluminum and other valuable components.

Continuum simulation of heat transfer and solidification behavior of AlSi10Mg in Direct Metal Laser Sintering Process

NASA Astrophysics Data System (ADS)

Ojha, Akash; Samantaray, Mihir; Nath Thatoi, Dhirendra; Sahoo, Seshadev

2018-03-01

Direct Metal Laser Sintering (DMLS) process is a laser based additive manufacturing process, which built complex structures from powder materials. Using high intensity laser beam, the process melts and fuse the powder particles makes dense structures. In this process, the laser beam in terms of heat flux strikes the powder bed and instantaneously melts and joins the powder particles. The partial solidification and temperature distribution on the powder bed endows a high cooling rate and rapid solidification which affects the microstructure of the build part. During the interaction of the laser beam with the powder bed, multiple modes of heat transfer takes place in this process, that make the process very complex. In the present research, a comprehensive heat transfer and solidification model of AlSi10Mg in direct metal laser sintering process has been developed on ANSYS 17.1.0 platform. The model helps to understand the flow phenomena, temperature distribution and densification mechanism on the powder bed. The numerical model takes into account the flow, heat transfer and solidification phenomena. Simulations were carried out for sintering of AlSi10Mg powders in the powder bed having dimension 3 mm × 1 mm × 0.08 mm. The solidification phenomena are incorporated by using enthalpy-porosity approach. The simulation results give the fundamental understanding of the densification of powder particles in DMLS process.

Structural Investigation of Alkali Activated Clay Minerals for Application in Water Treatment Systems

NASA Astrophysics Data System (ADS)

Bumanis, G.; Bajare, D.; Dembovska, L.

2015-11-01

Alkali activation technology can be applied for a wide range of alumo-silicates to produce innovative materials with various areas of application. Most researches focuse on the application of alumo-silicate materials in building industry as cement binder replacement to produce mortar and concrete [1]. However, alkali activation technology offers high potential also in biotechnologies [2]. In the processes where certain pH level, especially alkaline environment, must be ensured, alkali activated materials can be applied. One of such fields is water treatment systems where high level pH (up to pH 10.5) ensures efficient removal of water pollutants such as manganese [3]. Previous investigations had shown that alkali activation technology can be applied to calcined clay powder and aluminium scrap recycling waste as a foam forming agent to create porous alkali activated materials. This investigation focuses on the structural investigation of calcined kaolin and illite clay alkali activation processes. Chemical and mineralogical composition of both clays were determined and structural investigation of alkali activated materials was made by using XRD, DTA, FTIR analysis; the microstructure of hardened specimens was observed by SEM. Physical properties of the obtained material were determined. Investigation indicates the essential role of chemical composition of the clay used in the alkali activation process, and potential use of the obtained material in water treatment systems.

Facile preparation and formation mechanism of Sr2Si5N8:Eu2+ red-emitting phosphors

NASA Astrophysics Data System (ADS)

Wang, Yang; Wang, Yunli; Wang, Ming; Shao, Yiran; Zhu, Yingchun

2018-05-01

The red-emitting Sr2Si5N8:Eu2+ phosphors have been synthesized in a new facile process using (oxy)nitride precursors by inductive calcination under N2 atmosphere at ordinary pressure. Different from the prevailing methods, lower cost raw materials, simpler pretreatment, without harsh conditions and a shorter reaction time are achieved. It was found that red-emitting Sr2Si5N8:Eu2+ phosphors were synthesized with high crystallinity and purity after 1 h inductive calcination. The formation mechanism was characterized by XRD, SEM, TEM and Fluorescence microscopy. It was demonstrated that a hexagonal mesophase of Sr-doped α-Si3N4 was primarily formed in the reaction process, which transformed into the final product of the orthorhombic Sr2Si5N8:Eu2+ phosphors. During the reaction process, the color of the samples transforms from greenish-yellow to orange and eventually to red. The as-prepared phosphors have a wide excitation in the range of 250 ∼ 570 nm which matches blue light chips and give a red-light emission peaking at 610 nm. The results indicate a promising prospect for a simple, efficient and inexpensive way to prepare Sr2Si5N8:Eu2+ phosphors for blue/UV-based warm-white LEDs and other fluorescent applications.

In situ characterization of uranium and americium oxide solid solution formation for CRMP process: first combination of in situ XRD and XANES measurements.

PubMed

Caisso, Marie; Picart, Sébastien; Belin, Renaud C; Lebreton, Florent; Martin, Philippe M; Dardenne, Kathy; Rothe, Jörg; Neuville, Daniel R; Delahaye, Thibaud; Ayral, André

2015-04-14

Transmutation of americium in heterogeneous mode through the use of U1-xAmxO2±δ ceramic pellets, also known as Americium Bearing Blankets (AmBB), has become a major research axis. Nevertheless, in order to consider future large-scale deployment, the processes involved in AmBB fabrication have to minimize fine particle dissemination, due to the presence of americium, which considerably increases the risk of contamination. New synthesis routes avoiding the use of pulverulent precursors are thus currently under development, such as the Calcined Resin Microsphere Pelletization (CRMP) process. It is based on the use of weak-acid resin (WAR) microspheres as precursors, loaded with actinide cations. After two specific calcinations under controlled atmospheres, resin microspheres are converted into oxide microspheres composed of a monophasic U1-xAmxO2±δ phase. Understanding the different mechanisms during thermal conversion, that lead to the release of organic matter and the formation of a solid solution, appear essential. By combining in situ techniques such as XRD and XAS, it has become possible to identify the key temperatures for oxide formation, and the corresponding oxidation states taken by uranium and americium during mineralization. This paper thus presents the first results on the mineralization of (U,Am) loaded resin microspheres into a solid solution, through in situ XAS analysis correlated with HT-XRD.

Biodiesel production via the transesterification of soybean oil using waste starfish (Asterina pectinifera).

PubMed

Jo, Yong Beom; Park, Sung Hoon; Jeon, Jong-Ki; Ko, Chang Hyun; Ryu, Changkook; Park, Young-Kwon

2013-07-01

Calcined waste starfish was used as a base catalyst for the production of biodiesel from soybean oil for the first time. A batch reactor was used for the transesterification reaction. The thermal characteristics and crystal structures of the waste starfish were investigated by thermo-gravimetric analysis and X-ray diffraction. The biodiesel yield was determined by measuring the content of fatty acid methyl esters (FAME). The calcination temperature appeared to be a very important parameter affecting the catalytic activity. The starfish-derived catalyst calcined at 750 °C or higher exhibited high activity for the transesterification reaction. The FAME content increased with increasing catalyst dose and methanol-over-oil ratio.

Effect of calcination temperature on the lithiation capacities of carbon-coated titania nanotubes synthesized by anodization

NASA Astrophysics Data System (ADS)

Seo, Min-Su; Lee, Hyukjae

2012-06-01

Carbon-coated titania nanotubes are synthesized via anodization in perchlorate containing electrolyte and subsequent hydrothermal reaction with glucose. Carbon coating improves the lithiation capacity of the titania nanotubes only when calcined at temperatures above 600°C, and the maximum capacity is ˜162 mAhg-1 at the 50th cycle from the titania nanotubes calcined at 700°C. The improved capacity of carbon-coated titania nanotubes is caused by the enhanced conductivity from the carbon. This is different from the role of the carbon coating in the hydrothermally prepared carbon-coated titania nanotubes, in which the coated carbon limits severe agglomeration.

The effect of calcination temperature on the performance of Co3O4-Bi2O3 as a heterogeneous catalyst of peroxymonosulfate

NASA Astrophysics Data System (ADS)

Zhang, Guangshan; Hu, Limin; Wang, Peng; Yuan, Yixing

2017-11-01

In this work, a time-saving microwave-assisted method for synthesis of Co3O4-Bi2O3 was reported. The synthesized Co3O4-Bi2O3 samples were characterized with different techniques to probe their crystalline structures and morphologies. The catalytic performances of synthesized Co3O4-Bi2O3 as peroxymonosulfate activator were evaluated by the degradation of bisphenol A. The effect of calcination temperature on Co3O4-Bi2O3 products was explored and the result showed that the sample calcined at 400 °C possessing superior catalytic activity.

Bedform Dimensions and Suspended Sediment Observations in a Mixed Sand-Mud Intertidal Environment

NASA Astrophysics Data System (ADS)

Lichtman, I. D.; Amoudry, L.; Peter, T.; Jaco, B.

2016-02-01

Small-scale bedforms, such as ripples, can profoundly modify near-bed hydrodynamics, near-bed sediment transport and resuspension, and benthic-pelagic fluxes. Knowledge of their dimensions is important for a number of applications. Fundamentally different processes can occur depending on the dimensions of ripples: for low and long ripples, the bed remains dynamically flat and diffusive processes dominate sediment entrainment; for steep ripples, flow separation occurs above the ripples creating vortices, which are far more efficient at entraining sediment into the water column. Recent laboratory experiments for mixtures of sand and mud have shown that bedform dimensions decrease with increasing sediment mud content. However, these same experiments also showed that mud is selectively taken into suspension when bedforms are created and migrate on the bed, leaving sandy bedforms. This entrainment process, selectively suspending fine sediment, is referred to as winnowing. To improve our understanding of bedform and entrainment dynamics of mixed sediments, in situ observations were made on intertidal flats in the Dee Estuary, United Kingdom. A suite of instruments were deployed collecting co-located measurements of the near-bed hydrodynamics, waves, small-scale bed morphology and suspended sediment. Three sites were occupied consecutively, over a Spring-Neap cycle, collecting data for different bed compositions, tide levels and wind conditions. Bed samples were taken when the flats became exposed at low water and a sediment trap collected suspended load when inundated. This study will combine these measurements to investigate the interactions between small-scale bed morphology, near-bed hydrodynamics and sediment entrainment. We will examine bedform development in the complex hydrodynamic and wave climate of tidal flats, in relation to standard ripple predictors. We will also relate the variability in small-scale bedforms to variation in hydrodynamic and wave conditions, and to suspension and entrainment processes for mixed sediments.

Persistence of exponential bed thickness distributions in the stratigraphic record: Experiments and theory

NASA Astrophysics Data System (ADS)

Straub, K. M.; Ganti, V. K.; Paola, C.; Foufoula-Georgiou, E.

2010-12-01

Stratigraphy preserved in alluvial basins houses the most complete record of information necessary to reconstruct past environmental conditions. Indeed, the character of the sedimentary record is inextricably related to the surface processes that formed it. In this presentation we explore how the signals of surface processes are recorded in stratigraphy through the use of physical and numerical experiments. We focus on linking surface processes to stratigraphy in 1D by quantifying the probability distributions of processes that govern the evolution of depositional systems to the probability distribution of preserved bed thicknesses. In this study we define a bed as a package of sediment bounded above and below by erosional surfaces. In a companion presentation we document heavy-tailed statistics of erosion and deposition from high-resolution temporal elevation data recorded during a controlled physical experiment. However, the heavy tails in the magnitudes of erosional and depositional events are not preserved in the experimental stratigraphy. Similar to many bed thickness distributions reported in field studies we find that an exponential distribution adequately describes the thicknesses of beds preserved in our experiment. We explore the generation of exponential bed thickness distributions from heavy-tailed surface statistics using 1D numerical models. These models indicate that when the full distribution of elevation fluctuations (both erosional and depositional events) is symmetrical, the resulting distribution of bed thicknesses is exponential in form. Finally, we illustrate that a predictable relationship exists between the coefficient of variation of surface elevation fluctuations and the scale-parameter of the resulting exponential distribution of bed thicknesses.

Fluidization quality analyzer for fluidized beds

DOEpatents

Daw, C. Stuart; Hawk, James A.

1995-01-01

A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence.

Fluidization quality analyzer for fluidized beds

DOEpatents

Daw, C.S.; Hawk, J.A.

1995-07-25

A control loop and fluidization quality analyzer for a fluidized bed utilizes time varying pressure drop measurements. A fast-response pressure transducer measures the overall bed pressure drop, or over some segment of the bed, and the pressure drop signal is processed to produce an output voltage which changes with the degree of fluidization turbulence. 9 figs.

Assessment of Service Life for Regenerative ECLSS Resin Beds

NASA Technical Reports Server (NTRS)

Cloud, Dale L.; Keilich, Maria C.; Polis, Peter C.; Yanczura, Stephen J.

2013-01-01

The International Space Station (ISS) Water Processor Assembly (WPA) and Oxygen Generation Assembly (OGA) manage and process water at various levels of cleanliness for multiple purposes. The effluent of theWPA and the influent of the OGA require water at very high levels of purity. The bulk of the water purification that occurs in both systems is performed by consumable activated carbon and ion exchange resin beds. Replacement beds must be available on orbit in order to continue the ISS critical processes of water purification and oxygen generation. Various hurdles exist in order to ensure viable spare resin beds. These include the characteristics of resin beds such as: storage environment, shelf life requirements, microbial growth, and variations in the levels and species of contaminants the beds are required to remove. Careful consideration has been given to match water models, bed capacities and spares traffic models to ensure that spares are always viable. The results of these studies and considerations, in particular, how shelf life requirements affect resin bed life management, are documented in this paper.

PROCESS OF RECOVERING URANIUM

DOEpatents

Carter, J.M.; Larson, C.E.

1958-10-01

A process is presented for recovering uranium values from calutron deposits. The process consists in treating such deposits to produce an oxidlzed acidic solution containing uranium together with the following imparities: Cu, Fe, Cr, Ni, Mn, Zn. The uranium is recovered from such an impurity-bearing solution by adjusting the pH of the solution to the range 1.5 to 3.0 and then treating the solution with hydrogen peroxide. This results in the precipitation of uranium peroxide which is substantially free of the metal impurities in the solution. The peroxide precipitate is then separated from the solution, washed, and calcined to produce uranium trioxide.

Composition and process for making an insulating refractory material

DOEpatents

Pearson, Alan; Swansiger, Thomas G.

1998-04-28

A composition and process for making an insulating refractory material. The composition includes calcined alumina powder, flash activated alumina powder, an organic polymeric binder and a liquid vehicle which is preferably water. Starch or modified starch may also be added. A preferred insulating refractory material made with the composition has a density of about 2.4-2.6 g/cm.sup.3 with reduced thermal conductivity, compared with tabular alumina. Of importance, the formulation has good abrasion resistance and crush strength during intermediate processing (commercial sintering) to attain full strength and refractoriness, good abrasion resistance and crush strength.

46 CFR 148.04-15 - Petroleum coke, uncalcined; petroleum coke, uncalcined and calcined (mixture).

Code of Federal Regulations, 2010 CFR

2010-10-01

... 46 Shipping 5 2010-10-01 2010-10-01 false Petroleum coke, uncalcined; petroleum coke, uncalcined and calcined (mixture). 148.04-15 Section 148.04-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND... Requirements for Certain Material § 148.04-15 Petroleum coke, uncalcined; petroleum coke, uncalcined and...

Attrition resistant Fischer-Tropsch catalyst and support

DOEpatents

Singleton, Alan H.; Oukaci, Rachid; Goodwin, James G.

2004-05-25

A catalyst support having improved attrition resistance and a catalyst produced therefrom. The catalyst support is produced by a method comprising the step of treating calcined .gamma.-alumina having no catalytic material added thereto with an acidic aqueous solution having an acidity level effective for increasing the attrition resistance of the calcined .gamma.-alumina.

Standardization and quality control parameters for Muktā Bhasma (calcined pearl)

PubMed Central

Joshi, Namrata; Sharma, Khemchand; Peter, Hema; Dash, Manoj Kumar

2015-01-01

Background: Muktā Bhasma (MB) is a traditional Ayurvedic preparation for cough, breathlessness, and eye disorders and is a powerful cardiac tonic, mood elevator, and known to promote strength, intellect, and semen production. Objectives: The present research work was conducted to generate fingerprint for raw and processed MB for quality assessment and standardization using classical and other techniques. Setting and Design: Three samples of MB were prepared by purification (śodhana) of Muktā (pearl) followed by repeated calcinations (Māraṇa). Resultant product was subjected to organoleptic tests and Ayurvedic tests for quality control such as rekhāpūrṇatā, vāritaratva, and nirdhūmatva. Materials and Methods: For quality control, physicochemical parameters such as loss on drying, total ash value, acid insoluble ash, specific gravity, pH value, and other tests using techniques such as elemental analysis with energy dispersive X-ray analysis (EDAX), Structural study with powder X-ray diffraction, particle size with scanning electron microscopy (SEM) were carried out on raw Muktā, Śodhita Muktā, and triplicate batches of MB. Results: The study showed that the raw material Muktā was calcium carbonate in aragonite form, which on repeated calcinations was converted into a more stable calcite form. SEM studies revealed that in raw and purified materials the particles were found scattered and unevenly arranged in the range of 718.7–214.7 nm while in final product, uniformly arranged, stable, rod-shaped, and rounded particles with more agglomerates were observed in the range of 279.2–79.93 nm. EDAX analysis revealed calcium as a major ingredient in MB (average 46.32%) which increased gradually in the stages of processing (raw 34.11%, Śodhita 37.5%). Conclusion: Quality control parameters have been quantified for fingerprinting of MB prepared using a particular method. PMID:26600667

Up-conversion monodispersed spheres of NaYF4:Yb3+/Er3+: green and red emission tailoring mediated by heating temperature, and greatly enhanced luminescence by Mn2+ doping.

PubMed

Zhu, Qi; Song, Caiyun; Li, Xiaodong; Sun, Xudong; Li, Ji-Guang

2018-04-09

Submicron sized, monodispersed spheres of Mn2+, Yb3+/Er3+ and Mn2+/Yb3+/Er3+ doped α-NaYF4 were easily autoclaved from mixed solutions of the component nitrates and ammonium fluoride (NH4F), in the presence of EDTA-2Na. Detailed characterizations of the resultant phosphors were obtained using XRD, Raman spectroscopy, FE-SEM, HR-TEM, STEM, PLE/PL spectroscopy, and fluorescence decay analysis. Finer structure and better crystal perfection was observed at a higher calcination temperature, and the spherical shape and excellent dispersion of the original particles was retained at temperatures up to 600 °C. Under the 980 nm infrared excitation, the Yb3+/Er3+-doped sample (calcined at 400 °C) exhibits a stronger green emission centered at ∼524 nm (2H11/2 → 4I15/2 transition of Er3+) and a weaker red emission centered at ∼657 nm (4F9/2 → 4I15/2 transition of Er3+). A 200 °C increase in the temperature from 400 °C to 600 °C resulted in the dominant red emission originating from the 4F9/2 → 4I15/2 transition of Er3+, instead of the previously dominant green one. Mn2+ doping induced a remarkable more enhanced intensity at ∼657 nm and ∼667 nm (red emission area) than that at ∼524 nm and ∼546 nm (green emission area), because of the non-radiative energy transfer between Mn2+ and Er3+. However, a poor thermal stability was induced by Mn2+ doping. The observed upconversion luminescence of the samples calcined at 400 °C and 600 °C followed the two photon process and the four photon process, respectively.

Formation of a vitreous phase at the surface of some commercial diatomaceous earth prevents the onset of oxidative stress effects.

PubMed

Ghiazza, Mara; Gazzano, Elena; Bonelli, Barbara; Fenoglio, Ivana; Polimeni, Manuela; Ghigo, Dario; Garrone, Edoardo; Fubini, Bice

2009-01-01

To understand the effect of the commercial processing of diatomaceous earths (DEs) on their ultimate surface structure and potential toxicity, we investigated the influence of the industrial processing and the nature of the deposit. Two flux calcined specimens from different deposits, DE/1-FC and DE/2-FC, and the simply calcined sample DE/1-C, from the same deposit as DE/1-FC, were compared in both their bulk and their surface properties. X-ray diffraction (XRD) analysis in a heating chamber revealed the presence of cristobalite in all samples, more abundant on the flux calcined ones. The crystal lattice is probably imperfect, as the alpha-beta transition, visible by XRD in DE/1-FC and DE/2-FC, is not detected by differential scanning calorimetry. Progressive etching with HF solutions suggests that most of the crystalline phase is at the core and not at the outer region of the samples. The combined use of spectroscopic (UV-vis and IR) and calorimetric techniques (heat of adsorption of water as a measure of hydrophilicity) reveals that DE/1-FC and DE/2-FC particles have an external layer of glass, absent in DE/1-C, where iron impurities act as network-forming and sodium ions as modifier species, with few patches of a hydrophobic phase, the latter relatable to a heated pure silica phase. When tested on a macrophage cell line (MH-S) in comparison with appropriate positive and negative controls (an active and an inactive quartz dust, respectively), only DE/1-C exhibited a cell damage and activation similar to that of active quartz (measured by lactate dehydrogenase release, peroxidation of membrane lipids and synthesis of NO). It is likely that the presence of a vitreous phase mitigates or even eliminates the cellular responses of silica in DE.

The influence of coating solution and calcination condition on the durability of Ir1-xSnxO2/Ti anodes for oxygen evolution

NASA Astrophysics Data System (ADS)

Kato, Zenta; Kashima, Ryo; Tatsumi, Kohei; Fukuyama, Shinnosuke; Izumiya, Koichi; Kumagai, Naokazu; Hashimoto, Koji

2016-12-01

For oxygen formation without forming chlorine in seawater electrolysis for hydrogen production we have been using the anode consisting of three layers of MnO2-type multiple oxide catalyst, intermediate layer and titanium substrate. The intermediate layer was used for prevention of oxidation of the titanium substrate during anodic polarization for oxygen evolution and was prepared by calcination of butanol solutions of H2IrCl6 and SnCl4 coated on titanium. The protectiveness of Ir1-xSnxO2 layer formed was directly examined using Ir1-xSnxO2/Ti anodes in H2SO4 solution changing the preparation conditions of the layer. When the sum of Ir4+ and Sn4+ was 0.1 M, the highest protectiveness was observed at 0.06 M Sn4+. Although an increase in calcination temperature led to the formation of Ir1-x-ySnxTiyO2 triple oxide with a slightly lower catalytic activity for oxygen evolution, the anode calcined at 450 °C showed the highest protectiveness.

Calcination temperature effect on the microstructure and dielectric properties of M-type strontium hexagonal ferrites

NASA Astrophysics Data System (ADS)

Mohammed, J.; Sharma, Jyoti; Kumar, Sachin; Trudel, T. T. Carol; Srivastava, A. K.

2017-07-01

M-type hexagonal ferrites have found wide application in electronics industry due to the possibility of tuning properties such as dielectric properties. An improved dielectric property is useful in high frequency application. In this paper, we studied the effect of calcination temperature on structural and dielectric properties of Al-Mn substituted M-type strontium hexagonal ferrites with chemical composition Sr1-xAlxFe12-yMnyO19 (x=0.3 and y=0.6) synthesized by sol-gel auto-combustion method. The prepared sample was sintered at four different temperatures (T=750°C, 850°C, 950°C and 1050°C) for 5 hours. Characterisations of the synthesized samples were carried out using X-ray diffraction (XRD), impedance analyser, field emission electron microscope (FE-SEM) and energy dispersive X-ray (EDX) spectroscopy. The dielectric properties were explained on the basis of Koop's phenomenological theory and Maxwell Wagner theory. The sample calcinated at 750°C shows the highest value of dielectric constant and AC conductivity whereas that calcinated at 1050°C exhibit the lowest dielectric losses.

Photoemission and energy gap of MgWO4 particles connecting as nanofibers synthesized by electrospinning-calcination combinations

NASA Astrophysics Data System (ADS)

Wannapop, Surangkana; Thongtem, Titipun; Thongtem, Somchai

2012-03-01

Mixtures of magnesium acetate tetrahydrate ((CH3COO)2Mg·4H2O), ammonium tungstate tetrahydrate ((NH4)6W7O24·4H2O), and poly(vinyl alcohol) with the molecular weight of 72,000 were electrospun through a +15 kV direct voltage to form fibers on ground flat aluminum foils. The electrospun fibers of 1.5, 3.0, and 4.5 mmol of each starting material containing 1.3 g poly(vinyl alcohol) were further calcined at 500-700 °C for 3 h constant length of time. At 500 and 600 °C calcination, both monoclinic and anorthic phases of MgWO4 particles with different sizes connecting as fibrous assemblies were detected. Upon increasing the calcination temperature to 700 °C, only monoclinic phase of facet nanoparticles interconnecting along the fibrous axes with 4.19 eV indirect band gap and 461 nm photoemission was synthesized. In the present research, formation of MgWO4 molecules as well as nucleation and growth of nanoparticles was also proposed.

Molybdenum carbide supported nickel-molybdenum alloys for synthesis gas production via partial oxidation of surrogate biodiesel

NASA Astrophysics Data System (ADS)

Shah, Shreya; Marin-Flores, Oscar G.; Norton, M. Grant; Ha, Su

2015-10-01

In this study, NiMo alloys supported on Mo2C are synthesized by wet impregnation for partial oxidation of methyl oleate, a surrogate biodiesel, to produce syngas. When compared to single phase Mo2C, the H2 yield increases from 70% up to >95% at the carbon conversion of ∼100% for NiMo alloy nanoparticles that are dispersed over the Mo2C surface. Supported NiMo alloy samples are prepared at two different calcination temperatures in order to determine its effect on particle dispersion, crystalline phase and catalytic properties. The reforming test data indicate that catalyst prepared at lower calcination temperature shows better nanoparticle dispersion over the Mo2C surface, which leads to higher initial performance when compared to catalysts synthesized at higher calcination temperature. Activity tests using the supported NiMo alloy on Mo2C that are calcined at the lower temperature of 400 °C shows 100% carbon conversion with 90% H2 yield without deactivation due to coking over 24 h time-on-stream.

A new approach to define surface/sub-surface transition in gravel beds

NASA Astrophysics Data System (ADS)

Haynes, Heather; Ockelford, Anne-Marie; Vignaga, Elisa; Holmes, William

2012-12-01

The vertical structure of river beds varies temporally and spatially in response to hydraulic regime, sediment mobility, grain size distribution and faunal interaction. Implicit are changes to the active layer depth and bed porosity, both critical in describing processes such as armour layer development, surface-subsurface exchange processes and siltation/ sealing. Whilst measurements of the bed surface are increasingly informed by quantitative and spatial measurement techniques (e.g., laser displacement scanning), material opacity has precluded the full 3D bed structure analysis required to accurately define the surface-subsurface transition. To overcome this problem, this paper provides magnetic resonance imaging (MRI) data of vertical bed porosity profiles. Uniform and bimodal (σ g = 2.1) sand-gravel beds are considered following restructuring under sub-threshold flow durations of 60 and 960 minutes. MRI data are compared to traditional 2.5D laser displacement scans and six robust definitions of the surface-subsurface transition are provided; these form the focus of discussion.

In Situ 3D Monitoring of Geometric Signatures in the Powder-Bed-Fusion Additive Manufacturing Process via Vision Sensing Methods.

PubMed

Li, Zhongwei; Liu, Xingjian; Wen, Shifeng; He, Piyao; Zhong, Kai; Wei, Qingsong; Shi, Yusheng; Liu, Sheng

2018-04-12

Lack of monitoring of the in situ process signatures is one of the challenges that has been restricting the improvement of Powder-Bed-Fusion Additive Manufacturing (PBF AM). Among various process signatures.

Immobilization of lead in a Korean military shooting range soil using eggshell waste: an integrated mechanistic approach.

PubMed

Ahmad, Mahtab; Hashimoto, Yohey; Moon, Deok Hyun; Lee, Sang Soo; Ok, Yong Sik

2012-03-30

This study evaluated the effectiveness of eggshell and calcined eggshell on lead (Pb) immobilization in a shooting range soil. Destructive and non-destructive analytical techniques were employed to determine the mechanism of Pb immobilization. The 5% additions of eggshell and calcined eggshell significantly decreased the TCLP-Pb concentration by 68.8% due mainly to increasing soil pH. Eggshell and calcined-eggshell amendments decreased the exchangeable Pb fraction to ≈ 1% of the total Pb in the soil, while the carbonate-associated Pb fraction was increased to 40.0-47.1% at >15% application rates. The thermodynamic modeling on Pb speciation in the soil solution predicted the precipitation of Pb-hydroxide [Pb(OH)(2)] in soils amended with eggshell and calcined eggshell. The SEM-EDS, XAFS and elemental dot mapping revealed that Pb in soil amended with calcined eggshell was associated with Si and Ca, and may be immobilized by entrapping into calcium-silicate-hydrate. Comparatively, in the soil amended with eggshell, Pb was immobilized via formation of Pb-hydroxide or lanarkite [Pb(2)O(SO(4))]. Applications of amendments increased activities of alkaline phosphatase up to 3.7 times greater than in the control soil. The use of eggshell amendments may have potential as an integrated remediation strategy that enables Pb immobilization and soil biological restoration in shooting range soils. Copyright © 2012 Elsevier B.V. All rights reserved.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Manovic, V.; Anthony, E.J.; Loncarevic, D.

CaO-based looping cycles are promising processes for CO{sub 2} Capture from both syngas and flue gas. The technology is based on cyclical carbonation of CaO and regeneration of CaCO{sub 3} in a dual fluidized-bed reactor to produce a pure CO{sub 2} stream suitable for sequestration. Use of spent sorbent from CO{sub 2} looping cycles for SO{sub 2} capture is investigated. Three limestones were investigated: Kelly Rock (Canada), La Blanca (Spain), and Katowice (Poland, Upper Silesia). Carbonation/calcination cycles were performed in a tube furnace with both the original limestones and samples thermally pretreated for different times (i.e., sintered). The spent sorbentmore » samples were sulfated in a thermogravimetric analyzer (TGA). The changes in the resulting sorbent pore structure were then investigated using mercury porosimetry. It has been shown that the sulfation rates of both thermally pretreated and spent sorbent samples are lower in comparison with those of the original samples. However, final conversions of both spent and pretreated sorbents after longer sulfation time were comparable or higher than those observed for the original sorbents under comparable conditions. Maximum sulfation levels strongly depend on sorbent porosity and pore surface area. The results showed that spent sorbent samples from CO{sub 2} looping cycles can be used as sorbents for SO{sub 2} retention in cases where significant porosity loss does not occur during CO{sub 2} reaction cycles. In the case of spent Kelly Rock and Katowice samples, sorbent particles are practically uniformly sulfated, achieving final conversions that are determined by the total pore volume available for the bulky CaSO{sub 4} product.« less