Sample records for sintered iron ore

  1. Influencing factor of sinter body strength and its effects on iron ore sintering indexes

    NASA Astrophysics Data System (ADS)

    Zhang, Guo-liang; Wu, Sheng-li; Su, Bo; Que, Zhi-gang; Hou, Chao-gang; Jiang, Yao

    2015-06-01

    Sinter body strength, which reflects the strength of sinter, plays an important role in the improvement of sinter. In this study, the sinter body strengths of iron ores were measured using a microsintering method. The relationship between the chemical composition and sinter body strength was discussed. Moreover, sinter-pot tests were performed. The effects of sinter body strength on the sintering indexes were then elucidated, and the bottom limit of sinter body strength of blending ores was confirmed. In the results, the compressive strengths (CSs) of iron ores are observed to decrease with the increasing of the contents of loss on ignition (LOI), SiO2, and Al2O3; however, LOI of less than 3wt% does not substantially influence the CSs of fine ores. In the case of similar mineral composition, the porosity, in particular, the ratio between the number of large pores and the total number of pores, strongly influences the sinter body strength. With an increase of the blending-ore CSs used in sinter-pot tests, the yield, productivity, and tumbler strength increase, and the solid fuel consumption decreases. The CSs of the blending ores only slightly affect the sintering time. The CS bottom limit of the blending ores is 310 N. When the CSs of the blending ores increase by 10%, the yield, productivity, and tumbler index increase by 1.9%, 2.8%, and 2.0%, respectively, and the solid fuel consumption decreases by 1.9%.

  2. High-temperature performance prediction of iron ore fines and the ore-blending programming problem in sintering

    NASA Astrophysics Data System (ADS)

    Yan, Bing-ji; Zhang, Jian-liang; Guo, Hong-wei; Chen, Ling-kun; Li, Wei

    2014-08-01

    The high-temperature performance of iron ore fines is an important factor in optimizing ore blending in sintering. However, the application of linear regression analysis and the linear combination method in most other studies always leads to a large deviation from the desired results. In this study, the fuzzy membership functions of the assimilation ability temperature and the liquid fluidity were proposed based on the fuzzy mathematics theory to construct a model for predicting the high-temperature performance of mixed iron ore. Comparisons of the prediction model and experimental results were presented. The results illustrate that the prediction model is more accurate and effective than previously developed models. In addition, fuzzy constraints for the high-temperature performance of iron ore in this research make the results of ore blending more comparable. A solution for the quantitative calculation as well as the programming of fuzzy constraints is also introduced.

  3. NO x reduction by coupling combustion with recycling flue gas in iron ore sintering process

    Microsoft Academic Search

    Yan-Guang Chen; Zhan-Cheng Guo; Gen-Sheng Feng

    2011-01-01

    A new process called ‘NO\\u000a x\\u000a reduction by coupling combustion with recycling flue gas (RCCRF)’ was proposed to decrease NO\\u000a x\\u000a emission during the iron ore sintering process. The simulation test of NO\\u000a x\\u000a reduction was performed over sintered ore and in the process of coke combustion. Experimentally, NO\\u000a x\\u000a reduction was also carried out by sintering pot test. For

  4. Characteristics of fly ash from the dry flue gas desulfurization system for iron ore sintering plants

    Microsoft Academic Search

    Guanghong Sheng; Peng Huang; Yaqin Mou; Chenhui Zhou

    2011-01-01

    The characteristics of fly ash from the flue gas desulfurization (FGD) system are important for its reuse and are mainly depend on the desulfurization process. The physical and chemical properties of DSF ash, which refers to fly ash from the dry FGD system for the iron ore sintering process, were investigated. Its mineralogical contents were determined by X-ray diffraction and

  5. Characteristics of fly ash from the dry flue gas desulfurization system for iron ore sintering plants

    Microsoft Academic Search

    Guanghong Sheng; Peng Huang; Yaqin Mou; Chenhui Zhou

    2012-01-01

    The characteristics of fly ash from the flue gas desulfurization (FGD) system are important for its reuse and are mainly depend on the desulfurization process. The physical and chemical properties of DSF ash, which refers to fly ash from the dry FGD system for the iron ore sintering process, were investigated. Its mineralogical contents were determined by X-ray diffraction and

  6. Positive pulsed corona discharge process for simultaneous removal of SO2 and NOx from iron-ore sintering flue gas

    Microsoft Academic Search

    Young Sun Mok; In-Sik Nam

    1999-01-01

    We investigated the application of pulsed corona discharge process to the removal of SO2 and NOx from industrial flue gas of an iron-ore sintering plant. The study was performed on a pilot scale, which is the most advanced demonstration of this process. The flow rate of 5000 m3\\/h of the flue gas was successfully treated. The electrode structure of the

  7. Polycyclic aromatic hydrocarbon emission profiles and removal efficiency by electrostatic precipitator and wetfine scrubber in an iron ore sintering plant.

    PubMed

    Guerriero, Ettore; Lutri, Antonina; Mabilia, Rosanna; Scianò, Maria Concetta Tomasi; Rotatori, Mauro

    2008-11-01

    A monitoring campaign of polychlorinated dibenzo-p-dioxins and dibenzofurans, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyl was carried out in an Italian iron ore sintering plant by sampling the combustion gases at the electrostatic precipitator (ESP) outlet, at the Wetfine scrubber (WS) outlet, and by collecting the ESP dust. Few data are available on these micropollutants produced in iron ore sintering plants, particularly from Italian plants. This study investigates the PAH emission profiles and the removal efficiency of ESPs and WS. PAHs were determined at the stack, ESP outlet flue gases, and in ESP dust to characterize the emission profiles and the performance of the ESP and the WS for reducing PAH emission. The 11 PAHs monitored are listed in the Italian legislative decree 152/2006. The mean total PAH sum concentration in the stack flue gases is 3.96 microg/N x m3, in ESP outlet flue gases is 9.73 microg/N x m3, and in ESP dust is 0.53 microg/g. Regarding the emission profiles, the most abundant compound is benzo(b)fluoranthene, which has a relative low BaP toxic equivalency factors (TEF) value, followed by dibenzo(a,l)pyrene, which has a very high BaP(TEF) value. The emission profiles in ESP dust and in the flue gases after the ESP show some changes, whereas the fingerprint in ESP and stack flue gases is very similar. The removal efficiency of the ESP and of WS on the total PAH concentration is 5.2 and 59.5%, respectively. PMID:19044155

  8. Influence of CeO 2 on NO x emission during iron ore sintering

    Microsoft Academic Search

    Yanguang Chen; Zhancheng Guo; Zhi Wang

    2009-01-01

    The evolution of NOx during coke combustion in the presence and absence of CeO2 was studied in a quartz fixed bed reactor. The distribution of CeO2 in the coke was examined by SEM, and the effects of CeO2 loading and CeO2 particle size on NOx emission were discussed. NOx emission was also investigated by sintering pot tests with CeO2 modified

  9. Microbial reduction of iron ore

    DOEpatents

    Hoffmann, M.R.; Arnold, R.G.; Stephanopoulos, G.

    1989-11-14

    A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry. 11 figs.

  10. Microbial reduction of iron ore

    DOEpatents

    Hoffmann, Michael R. (Pasadena, CA); Arnold, Robert G. (Pasadena, CA); Stephanopoulos, Gregory (Pasadena, CA)

    1989-01-01

    A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry.

  11. Biologically induced iron ore at Gunma iron mine, Japan

    Microsoft Academic Search

    JUNJI AKAI; KURUMI AKAI; MAKOTO ITO; SATOSHI NAKANO; YONOSUKE MAKI; ICHIRO SASAGAWA

    1999-01-01

    The mineralogy of sedimentary iron ores from the Gunma iron mine are described to evaluate the role of microorganisms and plants in ore formation. The iron ore is composed of nanocrystalline goethite, well-crystallized jarosite and very small amounts of strengite. The ore characteristically occurs as thick-bands of alternating goethite and jarosite bands, thin-bands of different goethite grain sizes, and fossil-aggregate

  12. The sources of our iron ores. II

    USGS Publications Warehouse

    Burchard, E.F.

    1933-01-01

    In this instalment** the iron ore deposits of the Lake Superior States, which normally furnish about 80 per cent, of the annual output of the United States, are described together with historical notes on discovery and transportation of ore. Deposits in the Mississippi Valley and Western States are likewise outlined and the sources of imported ore are given. Reviewing the whole field, it is indicated that the great producing deposits of the Lake Superior and southern Appalachian regions are of hematite in basin areas of sedimentary rocks, that hydrated iron oxides and iron carbonates are generally found in undisturbed comparatively recent sediments, and that magnetite occurs in metamorphic and igneous rocks; also that numerical abundance of deposits is not a criterion as to their real importance as a source of supply. Statistics of production of iron ore and estimates of reserves of present grade conclude the paper.

  13. Processing of Goethitic Iron Ore Fines

    NASA Astrophysics Data System (ADS)

    Sharma, J.; Sharma, T.; Mandre, N. R.

    2015-05-01

    In the present investigation an attempt has been made to beneficiate goethitic iron ore containing 59.02 % Iron, 6.51 % Alumina, 4.79 % Silica, 0.089 % Phosphorus with 7.11 % loss on ignition. For this purpose, different beneficiation techniques such as gravity and magnetic separation processes have been employed. During the process two conceptual flow sheets were also developed for the beneficiation of goethite iron ore fines. In the prsent work it was possible to enhance grade of iron to 63.35, 63.18, and 65.35 % from Jigging, Multi Gravity Separation (MGS) and Wet High Intensity Magnetic Separator (WHIMS) respectively.

  14. Leaching of the residue from the dry off-gas de-dusting and desulfurization process of an iron ore sinter plant

    NASA Astrophysics Data System (ADS)

    Lanzerstorfer, Christof; Xu, Qi; Neuhold, Robert

    2015-02-01

    The residue from a second-stage dry sinter plant off-gas cleaning process contains both the fine dust from the sinter plant and the sorbent used. Recycling of the material that is usually handled by landfills to the sinter plant feed is not possible because of its chloride content. Leaching of the chlorides allow the recycling of remaining solids. The saline leachate produced contains some heavy metals and must be treated before it is discharged into the sea. In laboratory experiments, leaching tests with the subsequent treatment of the leachate were conducted. After the process was optimized, all heavy-metal concentrations were below the permissible values. The optimum treatment conditions for heavy-metal precipitation were observed to be the filtration of the suspended solids followed by the dosing of liquid with lime milk (pH 10) and the subsequent precipitation using sodium sulfide.

  15. Direct Biohydrometallurgical Extraction of Iron from Ore

    SciTech Connect

    T.C. Eisele

    2005-10-01

    A completely novel approach to iron extraction was investigated, based on reductive leaching of iron by anaerobic bacteria. Microorganisms were collected from an anaerobic bog where natural seepage of dissolved iron was observed. This mixed culture was used to reduce insoluble iron in a magnetite ore to the soluble ferrous (Fe{sup +2}) state. While dissolution rates were slow, concentrations of dissolved iron as high as 3487 mg/l could be reached if sufficient time was allowed. A factorial study of the effects of trace nutrients and different forms of organic matter indicated that the best dissolution rates and highest dissolved iron concentrations were achieved using soluble carbohydrate (sucrose) as the bacterial food source, and that nutrients other than nitrogen, phosphorus, potassium, sodium, and acetate were not necessary. A key factor in reaching high levels of dissolved iron was maintaining a high level of carbon dioxide in solution, since the solubility of iron carbonates increases markedly as the quantity of dissolved carbon dioxide increases. Once the iron is dissolved, it has been demonstrated that the ferrous iron can then be electroplated from solution, provided that the concentration of iron is sufficiently high and the hydrogen ion concentration is sufficiently low. However, if the leaching solution is electrolyzed directly, organic matter precipitates at the cathode along with the metallic iron. To prevent this problem, the ferrous iron should be separated from the bulk solution in a more concentrated, purified form. One route to accomplishing this is to take advantage of the change in solubility of ferrous iron as a function of carbon dioxide concentration. By cycling the concentration of carbon dioxide in solution, it is possible to produce an iron-rich concentrate that should be suitable for electrolysis. This represents the first viable hydrometallurgical method for leaching iron directly from ore and producing metallic iron.

  16. CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE ...

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

    CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE CARS TOWARDS WESTERN SIDE OF CLEVELAND BULK TERMINAL BUILDINGS AND A SELF-UNLOADING IRON ORE SHIP AT DOCK. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  17. Investigation of Conventional- and Induction-Sintered Iron and Iron-Based Powder Metal Compacts

    NASA Astrophysics Data System (ADS)

    Çavdar, U?ur; Atik, Enver

    2014-06-01

    Induction sintering was developed as an alternative method to conventional sintering to sinter iron-based powder metal (PM) compacts. Several compositions of compact such as pure iron, 3 wt.% copper mixed iron, or 3 wt.% bronze mixed iron were sintered by using induction sintering machines with 12 kW power and 30 kHz frequency. The mechanical properties, microstructural properties, densities, and microhardness values were investigated for both processes. Iron-based PM compacts sintered at 1120°C by induction in 8.33 min (500 s) were found to be similar to those sintered conventionally in 30 min. The results were compared with the experimental studies.

  18. 40 CFR 440.10 - Applicability; description of the iron ore subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...false Applicability; description of the iron ore subcategory. 440.10 Section...MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions...

  19. 40 CFR 440.10 - Applicability; description of the iron ore subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...false Applicability; description of the iron ore subcategory. 440.10 Section...MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions...

  20. 40 CFR 440.10 - Applicability; description of the iron ore subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...false Applicability; description of the iron ore subcategory. 440.10 Section...MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions...

  1. 40 CFR 440.10 - Applicability; description of the iron ore subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...false Applicability; description of the iron ore subcategory. 440.10 Section...MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions...

  2. Rare earth-iron-boron sintered magnets

    SciTech Connect

    Ghandehari, M.H.

    1991-05-14

    This paper describes a method for a permanent magnet comprising a heavy lanthanide metal near the grain boundaries of light rare earth-iron-boron particles. It comprises: mixing a particulate alloy containing at least one light rare earth metal, iron, boron, a ferromagnetic metal selected from the group consisting of nickel, cobalt, and mixtures thereof with at least one particulate metal additive containing a heavy lanthanide metal, the particulate alloy comprising a main magnetic phase having an empirical formula of about Nd{sub 2}(FeCo){sub 14}B; aligning magnetic domains of the mixture in a magnetic field; compacting the aligned mixture to form a shape; and sintering the compacted shape for sufficient time to produce the permanent magnet having the heavy lanthanide metal near the grain boundaries of particles of the main magnetic phase.

  3. Hyperspectral Mapping of Bif and Iron Ores

    NASA Astrophysics Data System (ADS)

    Ramanaidou, E. R.; Schodlok, M.

    2012-12-01

    INTRODUCTION In the last 20 years, hyperspectral reflectance in the visible and near infrared (VNIR), shortwave infrared (SWIR) and thermal infrared (TIR) wavelength ranges have emerged as an objective and quick method to map minerals. The combination of these wavelength ranges is ideal to characterize most of the minerals occurring in banded iron-formation (BIF) and BIF-hosted high grade iron ores. VNIR is ideal for characterizing and mapping the abundance of hematite and goethite. The SWIR provides information on OH-bearing silicates and carbonates. TIR shows specific spectral absorption for anhydrous minerals. INSTRUMENTS AND SAMPLES Three hyperspectral sensors were used: (1) the NEO HYSPEX, (2) the SPECIM TIR and the CSIRO HyLogging™ systems. Samples include drill core and hand samples of Australian BIF and iron ore. RESULTS AND CONCLUSION In the VNIR and SWIR, magnetite has a very low reflectance and a featureless spectrum. The main diagnostic feature for hematite and goethite is the wavelength of the ferric oxide absorption near 900 nm. The shift of the minimum wavelength and the width of the feature are correlated to the hematite goethite ratio. In the TIR range magnetite shows a significant spectral peak at around 17.5 ?m and an increase in reflectance between 6 and 14.5 ?m ranging from 5 to 10%. Hematite shows an absorption at 6.5 ?m. Goethite has a reflectance peak doublet; the first at 11.3 ?m and the second at 12.6 ?m. In the VNIR and SWIR, quartz shows no diagnostic feature. In the TIR, quartz has been identified by an absorption feature at 8.625 ?m. The spectral shape of the main quartz feature shows high variability due to surface scattering. The second characteristic quartz feature is the doublet peaks at 12.5 ?m and 12.8 ?m. In the VNIR and SWIR, the carbonates are detected by their reflectance absorption at around 2.33 ?m, a wavelength region already occupied by OH bearing Fe-Mg minerals. On the other end, in the TIR, carbonates show a strong reflectance peak at around 6.5 ?m and a weaker peak located around 11.3 ?m. In the studied samples, riebeckite was the dominant hydroxyl-silicate. In the VNIR and SWIR the diagnostic feature is the doublet absorption at 2.33 and 2.4 ?m, In the TIR, riebeckite shows a combination of a small but significant reflection peak at 10.38 ?m and an absorption trough at 12.62 ?m. Quartz, carbonates and riebeckite distributions and their relative abundances were successfully mapped by using a combination of VNIR-SWIR and TIR. Quartz was detected in six samples. Additionally two variations of quartz could be discriminated namely chert and chalcedony. Two populations of carbonates, respectively dolomite and siderite, were identified in the BIF samples based on TIR well cross validated with the SWIR. The definite determination of riebeckite was done using a combination of SWIR and TIR, as in the TIR overlap with other minerals can hide the riebeckite features at 10.38 ?m and 12.62 ?m. This study showed that a combination of VNIR SWIR and TIR improved the accuracy of spectral characterization of BIF and high iron ores.

  4. Coulometric investigation of the drying conditions of high-grade iron ores for chemical analysis.

    PubMed

    Yoshimori, T; Asano, Y; Harada, T

    1978-03-01

    Drying conditions for several iron ores have been investigated by the coulometric microdetermination of water. Samples, which were heated in an atmosphere of dry argon at 110 degrees for 3-4 hr and cooled, usually evolved less than 0.015% of water during a further 1 hr of heating. Therefore the difference in water content of the sample thus treated did not significantly influence the analytical results for total iron. Some magnetites and sintered pellet could be dried readily by heating for 2 hr in dry argon. Heating of samples of high water content for too long is not advisable as they may evolve some combined water. PMID:18962233

  5. Sintering of elemental carbonyl iron and carbonyl nickel powder mixtures

    Microsoft Academic Search

    TIEN-YIN CHAN; SHUN-TIAN LIN

    1997-01-01

    Iron-nickel alloys with compositions ranging from pure iron to pure nickel at increments of 10 wt% have been prepared by mixing\\u000a fine elemental carbonyl iron and nickel powders, and sintering at temperatures between 1200–1350C. The addition of nickel\\u000a to iron promoted densification and avoided abnormal grain growth at low concentrations. However the densification was retarded\\u000a when the iron and nickel

  6. Siderite formation and evolution of sedimentary iron ore deposition in the Earth's history

    NASA Astrophysics Data System (ADS)

    Kholodov, V. N.; Butuzova, G. Yu.

    2008-08-01

    The role of siderite in Phanerozoic and Precambrian iron formations is discussed. Various types of iron formations are characterized, and their place in the evolution of sedimentary iron ore deposition is outlined. In Precambrian iron ore deposition, siderite is a primary mineral, whereas in Phanerozoic iron formations it becomes a secondary mineral and is commonly related to diagenetic and catagenetic processes.

  7. Cs immobilization by sintered lead iron phosphate glasses

    Microsoft Academic Search

    S. T Reis; J. R Martinelli

    1999-01-01

    Lead iron phosphate glass frits were obtained from a mixture of NH4H2PO4, PbO and Fe2O3 melted in an induction furnace. After milling, the material was pressed in a die, sintered, and sintered a second time. Three amorphous X-ray diffraction halos were observed in samples produced from non-homogenized powders while two halos were observed from homogeneous ones. These halos were assigned

  8. China's emergence as the world's leading iron-ore-consuming country

    USGS Publications Warehouse

    Kirk, W.S.

    2004-01-01

    China has become the leading iron ore consuming nation, and, based on recent steel production capacity increases and plans for more, its consumption will almost certainly to continue to grow. China's iron ore industry, however, faces a number of problems. China's iron ore is low-grade, expensive to process, and its mines are being depleted. For many Chinese steelmakers, particularly in the coastal regions, the delivered cost of domestic iron ore, is more than the delivered cost of foreign ore. Thus China's iron ore imports are expected to increase. As China's growth continues, it will almost certainly surpass Japan to become the leading iron ore importing country as well. Without China's increasing appetite for iron ore, the world iron ore market would be flat or declining. China's recent imports largely offset the slump in demand in North America and Europe. China is regarded by the iron ore industry as the growth sector for the next decade. Although Chinese imports are expected to continue their rapid increase and imports in other Asian countries are expected to continue growing, there appears to be enough greenfield and expansion projects to meet future demand for iron ore worldwide. Present suppliers of iron ore, Australia, Brazil, India, and South Africa, will probably be the chief beneficiaries of China's increasing consumption of iron ore. How long China can continue its extraordinary growth is the primary issue for the future of the iron ore industry. Based on the number and size of planned blast furnaces it appears that China's growth could continue for several more years. ?? 2004 Taylor and Francis.

  9. Cancer of the lung in iron ore (haematite) miners

    PubMed Central

    Boyd, J. T.; Doll, R.; Faulds, J. S.; Leiper, J.

    1970-01-01

    Boyd, J. T., Doll, R., Faulds, J. S., and Leiper, J.(1970).Brit. J. industr. Med.,27, 97-105. Cancer of the lung in iron ore (haematite) miners. The mortality of Cumberland iron-ore miners has been studied by examining the death certificates of 5 811 men resident in two local authority areas (Ennerdale R.D. and Whitehaven M.B.) who died between 1948 and 1967. Comparison of the iron miners' experience with (1) that of other local men and (2) the relevant national experience has provided an assessment of the suspected occupational risk of lung cancer associated with haematite mining. During the 20-year period there were 42 deaths attributed to lung cancer among iron mine employees resident in the study area: 36 of these occurred in miners working underground, which was significantly greater than that expected from local non-mining (20·6 deaths) or national (21·5 deaths) experience. In contrast to these findings, there was no evidence of any excess mortality from lung cancer among surface workers and, for iron miners as a whole, mortality from other cancers was close to the national experience. A parallel analysis of mortality among coal miners showed a deficit of deaths from lung cancer in line with other studies. The patterns of other respiratory mortality in the two local mining groups were also in line with previous experience, and confirmed the existence of a substantial silicotic hazard associated with haematite mining in Cumberland. These findings strengthen previous necropsy evidence and indicate that West Cumberland iron-ore miners who work underground experience an occupational hazard of lung cancer. They suggest that the miners suffer a lung cancer mortality about 70% higher than `normal'. The risk may be due to radioactivity in the air of the mines (average radon concentration of 100 p Ci/litre) or to a carcinogenic effect of iron oxide. PMID:5448525

  10. Ore-car coupler performance at BHP-Billiton Iron Ore

    Microsoft Academic Search

    Robert Boelen; Paul Curcio; Alex Cowin; Russell Donnelly

    2004-01-01

    The world-class railway operated by BHP-Billiton Iron Ore now runs the highest axle loads globally. Loads have increased an average 16% to 37 tonnes\\/axle in the past 15 years. A single 330-car train is now being run daily, with a view to eventually increase the number of long trains to further improve productivity; currently 220-car trains form the major traffic.

  11. Direct reduction of iron ore by biomass char

    NASA Astrophysics Data System (ADS)

    Zuo, Hai-bin; Hu, Zheng-wen; Zhang, Jian-liang; Li, Jing; Liu, Zheng-jian

    2013-06-01

    By using thermogravimetric analysis the process and mechanism of iron ore reduced by biomass char were investigated and compared with those reduced by coal and coke. It is found that biomass char has a higher reactivity. The increase of carbon-to-oxygen mole ratio (C/O) can lead to the enhancement of reaction rate and reduction fraction, but cannot change the temperature and trend of each reaction. The reaction temperature of hematite reduced by biomass char is at least 100 K lower than that reduced by coal and coke, the maximum reaction rate is 1.57 times as high as that of coal, and the final reaction fraction is much higher. Model calculation indicates that the use of burden composed of biomass char and iron ore for blast furnaces can probably decrease the temperature of the thermal reserve zone and reduce the CO equilibrium concentration.

  12. Production of Iron-Ore Pellets with an Organic Binder

    Microsoft Academic Search

    V. M. Chizhikova; R. M. Vainshtein; S. N. Zorin; T. I. Zainetdinov; G. A. Zinyagin; A. A. Shevchenko

    2003-01-01

    Limestone is used as the flux in the production of iron-ore pellets, while bentonite clays are used as the binder. The consumption of these clays is within the range 0.4?3.0% [2]. Organic binders based on polyacrylamide can serve as a substitute for bentonite that makes it possible to reduce the consumption of binder and increase the Fe content of the

  13. Experimental research on the characteristics of softening and melting of iron ores as significant factor of influence on gas permeability of blast furnace charge

    NASA Astrophysics Data System (ADS)

    Branescu, E.; Blajan, A. O.; Constantin, N.

    2015-06-01

    It is widely accepted as a cohesive zone is directly influenced by softening and melting properties of iron ores, preparations (crowded, pellets, which represents about 90%, of the loads with metal furnace intake), or uncooked (raw ores ranked). Important results can be obtained through the study of behavior of ferrous materials at temperatures above 1000 ° C. Starting from research methods presented in the literature, this paper presents itself in carrying out their own laboratory experiments, conducted with the aim of analysing the softening and melting properties of sinter iron cores.

  14. Simulation of primary-slag melting behavior in the cohesive zone of a blast furnace, considering the effect of Al{sub 2}O{sub 3}, Fe{sub t}O, and basicity in the sinter ore

    SciTech Connect

    Hino, Mitsutaka; Nagasaka, Tetsuya; Katsumata, Akitoshi [Tohoku Univ., Sendai (Japan). Dept. of Metallurgy; Higuchi, Kenichi; Yamaguchi, Kazuyoshi; Kon-No, Norimitsu [Nippon Steel Corp., Futts (Japan). Process Technology Research Labs.

    1999-08-01

    The alumina content in the iron ore imported to Japan is increasing year by year, and some problems in blast furnace operation, due to the use of the high-alumina-containing sinter, have already been reported. In order to clarify the mechanism of the harmful effect of alumina on the blast furnace operation, the behavior of the primary melt, which is formed in the sinter at the cohesive zone of the blast furnace, has been simulated by dripping slag through an iron or oxide funnel. The effects of basicity, Al{sub 2}O{sub 3}, and Fe{sub t}O contents in the five slag systems on the dripping temperature and weight of slag remaining on the funnel have been discussed. It was found that the eutectic melt formed in the sinter would play an important role in the dripping behavior of the slag in the blast furnace through the fine porosity of the reduced iron and ore particles. Al{sub 2}O{sub 3} increased the weight of the slag remaining on the funnel, and its effect became very significant in the acidic and low-Fe{sub t}O-containing slag. It was estimated that the increase of the weight of the slag remaining on the funnel by Al{sub 2}O{sub 3} in the ore could result in a harmful effect on the permeability resistance and an indirect reduction rate of the sinter in the blast furnace.

  15. Characterization of an iron-based laser sintered material

    Microsoft Academic Search

    Y. Wang; J. Bergström; C. Burman

    2006-01-01

    Direct Metal Laser Sintering (DMLS) is a relatively new rapid tooling technique to fabricate near net-shaped parts. Properties of DMLS parts are governed by their microstructure. Hence, characterization of microstructure is of significant importance. In this study, a new iron-based DMLS material was characterized to unveil its metallic microstructure to support the prediction of end-user performance and the development of

  16. Synthesis process of forsterite refractory by iron ore tailings.

    PubMed

    Li, Jing; Wang, Qi; Liu, Jihui; Li, Peng

    2009-01-01

    With mineral resources becoming gradually more deficient, as well as the issue of mine tailings causing environmental pollution, more and more people have realized the great significance of tailings utilization. Iron ore tailings, as a kind of secondary resource, have been developed in recycling industries. The feasibility to produce forsterite refractory from high-silicon iron tailings and high-magnesium raw materials were discussed. Also, the synthesis reaction processes were studied from the results of the laboratory experiments. The experiments showed that the synthesis processes can be separated into three steps when using iron tailings to synthesize forsterite: (1) produce magnesium iron sosoloid (Mg1-XFeXO) and magnesium metasilicate (MgSiO3), (2) form the fayalite, and (3) create the forsterite. The synthetic productions are primarily forsterite, hortonolite, and small amounts of magnesium metasilicate (MgSiO3). The hortonolite is wrapped around the surface of the forsterite particles and formed the cementing phase. In addition, the method to produce forsterite refractory and lightweight forsterite refractory from iron tailings were offered. PMID:25084443

  17. Innovative methodology for comprehensive utilization of iron ore tailings: part 2: The residues after iron recovery from iron ore tailings to prepare cementitious material.

    PubMed

    Li, Chao; Sun, Henghu; Yi, Zhonglai; Li, Longtu

    2010-02-15

    In order to comprehensive utilization of iron ore tailings, this experimental research was to investigate the possibility of using the residues after iron recovery from iron ore tailings as raw materials for the preparation of cementitious material, abbreviated as TSC, including analyses of its mechanical properties, physical properties and hydration products. The TSC1 was prepared by blending 30% the residues, 34% blast-furnace slag, 30% clinker and 6% gypsum. Meanwhile, the raw iron ore tailings (before iron recovery) with the same proportion of TSC1 were selected to compare the cementitious activity of raw tailings and the residues after magnetizing roasting, denoted by TSC0. The hydration products of them were mostly ettringite, calcium hydroxide and C-S-H gel, characterized by XRD, IR and SEM. It was found that ettringite and C-S-H gel were principally responsible for the strength development of TSC mortars with curing time. The results showed that the kaolinite of the tailings was decomposed completely after magnetizing roasting, which promoted the cementitious property of TSC1. Moreover, the mechanical properties of TSC1 are well comparable with those of 42.5 ordinary Portland cement according to Chinese GB175-2007 standard. PMID:19782471

  18. Non-coke smelting reduction of iron ores: Process modelling

    NASA Astrophysics Data System (ADS)

    Pichestapong, Pipat

    The scarcity of coking coals and the high cost entailed in minimizing the emissions from the coke-making process as well as the relative inflexibility of large production capacity of the conventional blast-furnace ironmaking are the main reasons for the development of non-coke smelting reduction processes with the economical and ecological compatibility. The main objectives of the alternative processes development are to use ordinary coals directly, extend the range of usable raw materials, and allow the operation at a small scale. While most of smelting reduction processes are still in various stages of development, only the COREX ironmaking has successfully reached the industrial application with its first 300000 tpa plant operated in Pretoria, South Africa. The COREX process is composed of two main reactors: the vertical shaft furnace for the gaseous reduction of iron ore to sponge iron, and the melter-gasifier for the gasification of coal and smelting of iron. The gasification process generates the reducing gas mixture (CO and Hsb2) for use in the reduction furnace and also produces heat for smelting of the direct reduced iron. In the present work, the operating data of the COREX process are studied and process material and energy balances are prepared. The coal consumption rate of the COREX process is found higher than the coke consumption rate of the conventional process; however, the total energy consumption for the COREX process compares well with that of the blast furnace. The COREX process also generates surplus gas of high heating value which is suitable for many applications. A reduction model employing the diffusion-limited mass-transfer coupled with virtual equilibrium at core-interface is developed to determine the reduction of iron oxide pellets. The rate of oxygen-transfer between the solid and gas phases is computed by combining the Stefan-Maxwell multi-component diffusion formalism with the iterative equilibrium constant method. The computed results agree well with the observed data and the model is extended to simulate the reduction profiles in the reduction shaft of the COREX process. It is seen that the reduction process is mainly influenced by the pore-size and pore-structure of the reduced product layers.

  19. Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

    NASA Astrophysics Data System (ADS)

    Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

    2015-04-01

    India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled with kaolinite and gibbsite, which make it low grade. Massive iron ores are devoid of any lamination and usually associated with BHJ and lower shale. The thickness of the massive ore layer varies with the location. The massive iron ore grades in to well-developed bedded BHJ in depth. Blue dust occurs in association with BHJ as pockets and layers. Although blue dust and friable ore are both powdery ores, and subjected to variable degree of deformation, leading to the formation of folding, faulting and joints of complex nature produce favourable channels. Percolating water play an important role in the formation of blue dust and the subterranean solution offers the necessary acidic environment for leaching of quartz from the BHJ. The dissolution of silica and other alkalis are responsible for the formation of blue dust. The friable and powdery ore on the other hand are formed by soft laminated ore. As it is formed from the soft laminated ore, its alumina content remains high similar to soft laminated ore compaired to blue dust. Mineralogy study suggests that magnetite was the principal iron oxide mineral, now a relict phase whose depositional history is preserved in BHJ, where it remains in the form of martite. The platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Hard laminated ores, martite-goethite ore and soft laminated ore are resultant of desilicification process through the action of hydrothermal fluids. Geochemistry of banded iron-formations of the Noamundi-Koira iron ore deposits shows that they are detritus-free chemical precipitates. The mineralogical and geochemical data suggest that the hard laminated, massive, soft laminated ores and blue dust had a genetic lineage from BIF's aided with certain input from hydrothermal activity. The comparative study of major elemental composition of the basin samples and while plotting a binary diagram, it shows a relation between major oxides against iron oxides, in which iron oxides is taken as a reference oxide (Mirza, 2011). On the other hand

  20. Iron ore and coal: pricing and volume up for these key export commodities

    SciTech Connect

    NONE

    2006-01-15

    Australia's huge coal and iron ore industries are booming. Up until now, the majors have benefited handsomely, but smaller players are beginning to muscle in. The article discusses development in both industries. 1 fig., 4 photos.

  1. Magnetite mineral nanoparticles synthesized naturally in an iron ore deposit

    NASA Astrophysics Data System (ADS)

    Rivas-Sanchez, M. L.; Alva-Valdivia, L. M.

    2013-05-01

    We performed a mineralogical characterization and mineral magnetism study of the Peña Colorada iron ore, Mexico. The ore is formed partly by intergranular magnetite intergrowed with berthierine (Fe,Mg,Al)6(Si,Al)4O10(OH)8. The magnetite nanoparticles are forming aggregates of wide grain size spectra, from micro to nanometer scale. The smallest aggregates are formed by magnetite nanoparticles 2 to 30 grain size range, showing unusual physical and chemical behavior. The continuous agglomeration of nanoparticles formed more denser and compact magnetite microparticles. A magnetite concentrate to micrometric scale was reduced and divided into distinct range sizes: 85-56 ?m, 56-30 ?m, 30-22 ?m, 22-15 ?m, 15-10 ?m, 10-7 ?m and 7-1 ?m. Nanometric-scale magnetite 2-30 nm was identified by using high resolution Transmission Electron Microscopy (HRTEM). The magnetite and minerals associated were characterized by X-ray diffraction, transmitted and reflected light polarization, microscope and electron probe X-ray micro-analyzer, differential thermal analysis, gravimetric thermal analysis, and high-resolution transmission electron microscopy. Besides, results of Mössbauer spectroscopy, frequency-dependent magnetic susceptibility, isothermal remanent magnetization and magnetic susceptibility versus temperature were important in the research related to the origin of this deposit. To study magnetite nanoparticles, agglomeration processes and temperature effect implications, we developed an experimental process to re-create the environmental conditions that originated this nanoparticles. These processes start with direct precipitation to synthesize magnetite nanoparticles through a thermal and dehydration treatment of the berthierine base mineral, using diverse temperature ranges, from 360 °C to 750 °C and treatment time of two hours. This process allowed the nucleation and crystalline growth of a high number of magnetite nano-crystals with average size of 2 to 6 nm, homogeneous distribution in the colloidal matrix and a superparamagnetic behavior. Increase temperature provoke new magnetite nano-cores and constant growth of the ones already present. The union to magnetite nanoparticles favored the formation of aggregates nano-micrometric strongly compacted with the acquisition of ferromagnetic behavior. The mineralogical-textural characteristic of magnetite nanoparticles and its magnetic properties were an important guide to explain the environmental conditions for iron deposition, suggesting a marine sedimentary exhalative (SEDEX) origin assisted by bacterial.

  2. Phosphorus Removal of High Phosphorus Iron Ore by Gas-Based Reduction and Melt Separation

    Microsoft Academic Search

    Hui-qing TANG; Zhan-cheng GUO; Zhi-long ZHAO

    2010-01-01

    A new method (gas-based separation plus melt separation) has been proposed to remove phosphorus of the high phosphorus iron ore which was 1.25% of phosphorus content and 50.0% of iron content. HSC chemistry package and the coexistence theory of slag structure were adopted for theoretical analysis. The gas-based reduction was carried out using a lixed bed reactor and the ore

  3. Phosphorus retention capacity of iron-ore and blast furnace slag in subsurface flow constructed wetlands

    Microsoft Academic Search

    B. grüneberg; J. Kern

    Abstract The suitability of iron-ore and blast furnace slag for subsurface flow (SSF) constructed wetlands was studied over a period of four months. Dairy farm wastewater,(TP 45 mg l,) was promoted,by predominantly anaerobic,conditions due to continuous formation of amorphous,ferrous hydroxides. None of the substrates had adverse affects on reed growth. Keywords Phosphorus retention; constructed wetlands; iron-ore; blast furnace slag; dairy

  4. High temperature compatibility of nitrate salts, granite rock and pelletized iron ore

    Microsoft Academic Search

    V. P. Burolla; J. J. Bartel

    1979-01-01

    Under the direction of the Department of Energy, high-temperature (550°C) thermal energy storage concepts are being studied for application with second-generation solar central receiver thermal power systems. The report evaluates the compatibility of the current choice of working fluids with common granite rock and a pelletized iron ore. Results indicate that the long-term stability of iron-ore pellets in binary mixtures

  5. Integrated process for thermal cracking of heavy oil and reduction of iron ores

    SciTech Connect

    Koizumi, K.; Miura, E.; Mori, K.; Nishida, R.

    1982-06-15

    Vacuum distillation residue oil having a conradson carbon value of 5 to 40% and a specific gravity of 0.9 to 1.10 is thermally cracked in the presence of iron ore particles in fluidized state in a thermal cracking reactor thereby to produce light oils and cracked gases and to form by-product carbon, which is caused to deposit on the iron ore particles, which are then transferred to and heated at 800 to 1200/sup 0/ C in a reducing furnace to be reduced in a solid state reaction, into sponge iron. Thus, heavy oil is thermally cracked and sponge iron is produced by an economical, integrated process.

  6. Modeling of counter current moving bed gas-solid reactor used in direct reduction of iron ore

    Microsoft Academic Search

    Daniel R. Parisi; Miguel A. Laborde

    2004-01-01

    In this work, the shaft furnace reactor of the MIDREX® process is simulated. This is a counter current gas-solid reactor, which transforms iron ore pellets into sponge iron.Simultaneous mass and energy balance along the reactor leads to a set of ordinary differential equation with two points boundary conditions. The iron ore reduction kinetics was modelated with the unreacted shrinking core

  7. Sintering of ceramet iron in hydrogen with additions of hydrogen chloride

    Microsoft Academic Search

    R. A. Andriyevskiy; V. V. Panichkin; I. M. Fedorchenko

    1961-01-01

    Conclusions l.The optimum concentration of hydrogen chloride in the process of sintering cermet iron amounts to 5–10%. An intensive blowing with hydrogen at the end of the sintering cycle averts the harmful effect of HCl on the rust-resisting properties of sintered compacts.2.The effect produced by HCl additions becomes manifest only if the holding periods were longer than 10–15 min. The

  8. Thermal fatigue behavior of an iron-based laser sintered material

    Microsoft Academic Search

    Y. Wang; J. Bergström; C. Burman

    2009-01-01

    Direct metal laser sintering is a rapid manufacturing technique to make intricate and near net-shaped parts. An iron-based laser sintered metal was studied to evaluate its thermal fatigue properties. The test was performed using cylindrical specimens in a high power induction heating system equipped with a laser strain gauge for a contactless surface strain measurement. Initiation of thermal fatigue cracks

  9. Phytostabilisation potential of lemon grass (Cymbopogon flexuosus (Nees ex Stend) Wats) on iron ore tailings.

    PubMed

    Mohanty, M; Dhal, N K; Patra, P; Das, B; Reddy, P S R

    2012-01-01

    The present pot culture study was carried out for the potential phytostabilisation of iron ore tailings using lemon grass (Cymbopogon flexuosus) a drought tolerant, perennial, aromatic grass. Experiments have been conducted by varying the composition of garden soil (control) with iron ore tailings. The various parameters, viz. growth of plants, number of tillers, biomass and oil content of lemon grass are evaluated. The studies have indicated that growth parameters of lemon grass in 1:1 composition of garden soil and iron ore tailings are significantly more (-5% increase) compared to plants grown in control soil. However, the oil content of lemon grass in both the cases more or less remained same. The results also infer that at higher proportion of tailings the yield of biomass decreases. The studies indicate that lemongrass with its fibrous root system is proved to be an efficient soil binder by preventing soil erosion. PMID:23741871

  10. Graphite immobilisation in iron phosphate glass composite materials produced by microwave and conventional sintering routes

    NASA Astrophysics Data System (ADS)

    Mayzan, M. Z. H.; Stennett, M. C.; Hyatt, N. C.; Hand, R. J.

    2014-11-01

    An investigation of microwave and conventional processing of iron phosphate based graphite glass composite materials as potential wasteforms for the immobilisation of irradiated graphite is reported. For the base iron phosphate glass, full reaction of the raw materials and formation of a glass melt occurs with consequent removal of porosity at 8 min microwave processing. When graphite is present, iron phosphate crystalline phases are formed with higher levels of residual porosity than in the sample prepared using conventional sintering under argon. It is found that graphite reacts with the microwave field when in powder form but this reaction is minimised when the graphite is incorporated into a pellet, and that the graphite also impedes sintering of the glass. Mössbauer spectroscopy indicates that reduction of iron also occurs with concomitant graphite oxidation. Conventionally sintered samples had lower porosities than the equivalent microwaved ones.

  11. Structural controls on the formation and transposition of the Malmberget apatite iron ore deposit, northern Sweden

    NASA Astrophysics Data System (ADS)

    Bauer, Tobias; Sarlus, Zimer; Andersson, Joel; Kearney, Thomas

    2015-04-01

    The Malmberget mine is the World's second largest underground iron ore operation. It is composed of approximately 20 apatite iron ore bodies, whereas 13 ore bodies with 5-245 Mt each are presently mined. The massive magnetite ore is hosted within volcanic and volcaniclastic rocks. Host rocks within the entire area were subject to intense hydrothermal alteration. The ore reserves at beginning of 2012 totalled 290 Mt at 44 percent iron. Together with Kiruna and Svappavaara these three deposits stands for more than 90 percent of the iron ore production in Europe. An on-going collaborative research project aims at unravelling the structural geometries, relationships and control on ore formation and ore body transposition at different scales in the Gällivare district in general and in the Malmberget mine in particular. Recent results show the three-dimensional crustal architecture of the Malmberget deposit which has undergone at least two separate deformation events. The first deformation event (D1) resulted in the formation of a strong and penetrative cleavage (S1) forming a varyingly intense banding within the volcanic rocks. The D1-event coincides with the amphibolite facies peak metamorphism in the area. Distinct, biotite-rich D1 shear zones are spatially related to the majority of the S1-parallel massive magnetite bodies. These D1 shear zones seem to be responsible for a strong strain partitioning during D1. A second compressional event (D2) resulted in open to close folding of the S1 fabric, the D1 shear zones and the related ore bodies. The result is an asymmetric F2-synform with moderately south-west-plunging fold axis. Furthermore, distinct D2 high strain zones are responsible for local transposition of S1 fabrics, tight to isoclinal folding and channeling or re-mobilization of hydrothermal alteration minerals. Both deformation events are accompanied by syn- and late-tectonic granitic intrusions forming both foliated and unfoliated and commonly boudinaged granitic sheets and dikes. Strong hydrothermal alteration occurred during several phases and is spatially and temporally related to D1 and D2 structures. Based on the structural observations a robust three-dimensional framework model is currently constructed using MOVE by Midland Valley Exploration. The resulting 3D-model visualizes the F2 folding pattern, the spatial distribution of D1 and D2 high strain zones and the structural controls on both primary and remobilized ore minerals. This framework model can act as a base for further modelling actions as well as for production and near mine exploration purposes.

  12. Method for the production of mineral wool and iron from serpentine ore

    DOEpatents

    O'Connor, William K. (Albany, OR); Rush, Gilbert E. (Scio, OR); Soltau, Glen F. (Lebanon, OR)

    2011-10-11

    Magnesium silicate mineral wools having a relatively high liquidus temperature of at least about 1400.degree. C. and to methods for the production thereof are provided. The methods of the present invention comprise melting a magnesium silicate feedstock (e.g., comprising a serpentine or olivine ore) having a liquidus temperature of at least about 1400.degree. C. to form a molten magnesium silicate, and subsequently fiberizing the molten magnesium silicate to produce a magnesium silicate mineral wool. In one embodiment, the magnesium silicate feedstock contains iron oxide (e.g., up to about 12% by weight). Preferably, the melting is performed in the presence of a reducing agent to produce an iron alloy, which can be separated from the molten ore. Useful magnesium silicate feedstocks include, without limitation, serpentine and olivine ores. Optionally, silicon dioxide can be added to the feedstock to lower the liquidus temperature thereof.

  13. Determination of titanium and iron in ilmenite ores by cerate titrimetry 

    E-print Network

    Gainer, Alvis Beryl

    1959-01-01

    ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ ~ SUNNARY AND CONCLUSIONS SISLI~ ~ 16 17 19 23 26 28 LIST OF ILMSTRATIOHS Figure Page 1 Liquid Zinc Amalgaa Reduction Apparatus . . . . . . . . . . . . . . . 28 2 Aluninua Metal Foil Reduction Apparatus . . . . . . ~. . . . ~. . . 29 ABSTRACT... snd then the iron with cerium(IV) sulfate. A simple, rapidi snd accurate volumetric method has been developed for the simultaneous determination of titanium and iron coexisting in solution. Seven ilmenite ore samples obtained from New Jersey Zinc...

  14. The effect of copper on iron reduction and its application to the determination of total iron content in iron and copper ores by potassium dichromate titration.

    PubMed

    Hu, Hanjun; Tang, Yang; Ying, Haisong; Wang, Minghai; Wan, Pingyu; Jin Yang, X

    2014-07-01

    The International Standard Organization (ISO) specifies two titrimetric methods for the determination of total iron content in iron ores using potassium dichromate as titrant after reduction of the iron(III) by tin(II) chloride and/or titanium(III) chloride. These two ISO methods (ISO2597-1 and ISO2597-2) require nearly boiling-point temperature for iron(III) reduction and suffer from copper interference and/or mercury pollution. In this study, potassium borohydride was used for reduction of iron(III) catalyzed by copper ions at ambient temperatures. In the absence of copper, iron(III) reduction by potassium borohydride was sluggish while a trace amount of copper significantly accelerated the reduction and reduced potassium borohydride consumption. The catalytic mechanism of iron(III) reduction in sulfuric acid and hydrochloric acid was investigated. Potassium borohydride in sodium hydroxide solution was stable without a significant degradation within 24h at ambient conditions and the use of potassium borohydride prepared in sodium hydroxide solution was safe and convenient in routine applications. The applicability of potassium borohydride reduction for the determination of total iron content by potassium dichromate titration was demonstrated by comparing with the ISO standard method using iron and copper ore reference materials and iron ore samples. PMID:24840467

  15. Airway inflammation in iron ore miners exposed to dust and diesel exhaust

    Microsoft Academic Search

    E. Adelroth; U. Hedlund; A. Blomberg; R. Helleday; M. C. Ledin; J. O. Levin; J. Pourazar; T. Sandstrom; B. Jarvholm

    2006-01-01

    The aim of the present study was to investigate if underground miners exposed to dust and diesel exhaust in an iron ore mine would show signs of airway inflammation as reflected in induced sputum. In total, 22 miners were studied, once after a holiday of at least 2 weeks and the second time after 3 months of regular work. Control

  16. Consolidation and DC magnetic properties of nanocrystalline Supermalloy/iron composite cores prepared by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Neam?u, B. V.; Chicina?, I.; Isnard, O.; Ciascai, I.; Popa, F.; Marinca, T. F.

    2014-03-01

    The spark plasma sintering technique is used to prepare composite compacts starting from nanocrystalline Supermalloy and iron powder. The sintered compacts are investigated by X-ray diffraction, scanning electron microscopy, X-ray microanalysis, electrical resistivity and DC magnetic measurements. It is found that iron addition leads to an enhanced sintering process, the relative density of the compacts increases upon increasing iron content. The mean crystallite size of Supermalloy increases from 19 to 27±2 nm with increasing the iron content from 0% to 50 wt% (for identical sintering conditions). The interface created during the sintering process between iron and Supermalloy particles has a wide range of chemical composition including that corresponding to Rhometal like alloys. This leads to an increase of the electrical resistivity and coercivity of the compacts. The saturation induction and maximum relative permeability increase by 58% and 143% respectively, when the iron content increases up to 50 wt%.

  17. Utilization of Coke Oven Gas and Converter Gas in the Direct Reduction of Lump Iron Ore

    NASA Astrophysics Data System (ADS)

    Mousa, Elsayed Abdelhady; Babich, Alexander; Senk, Dieter

    2014-04-01

    The application of off-gases from the integrated steel plant for the direct reduction of lump iron ore could decrease not only the total production cost but also the energy consumption and CO2 emissions. The current study investigates the efficiency of reformed coke oven gas (RCOG), original coke oven gas (OCOG), and coke oven gas/basic oxygen furnace gas mixtures (RCOG/BOFG and OCOG/BOFG) in the direct reduction of lump iron ore. The results were compared to that of reformed natural gas (RNG), which is already applied in the commercial direct reduction processes. The reduction of lump ore was carried out at temperatures in the range of 1073 K to 1323 K (800 °C to 1050 °C) to simulate the reduction zone in direct reduction processes. Reflected light microscopy, scanning electron microscopy, and X-ray diffraction analysis were used to characterize the microstructure and the developed phases in the original and reduced lump iron ore. The rate-controlling mechanism of the reduced lump ore was predicted from the calculation of apparent activation energy and the examination of microstructure. At 1073 K to 1323 K (800 °C to 1050 °C), the reduction rate of lump ore was the highest in RCOG followed by OCOG. The reduction rate was found to decrease in the order RCOG > OCOG > RNG > OCOG-BOF > RCOG-BOFG at temperatures 1173 K to 1323 K (900 °C to 1050 °C). The developed fayalite (Fe2SiO4), which resulted from the reaction between wüstite and silica, had a significant effect on the reduction process. The reduction rate was increased as H2 content in the applied gas mixtures increased. The rate-determining step was mainly interfacial chemical reaction with limitation by gaseous diffusion at both initial (20 pct reduction) and moderate (60 pct reduction) stages of reduction. The solid-state diffusion mechanism affected the reduction rate only at moderate stages of reduction.

  18. Laser sintering of separated and uniformly distributed multiwall carbon nanotubes integrated iron nanocomposites

    NASA Astrophysics Data System (ADS)

    Lin, Dong; Richard Liu, C.; Cheng, Gary J.

    2014-03-01

    Uniform distribution of carbon nanotubes (CNTs) in metal matrix during additive manufacturing of nanocomposites is always a challenge since the CNTs tend to aggregate in the molten pool. In this study, Multiwall carbon nanotubes (MWNTs) were separated and distributed uniformly into iron matrix by laser sintering process. MWNTs and iron powders were mixed together by magnetic stir, coated on steel 4140 surface, followed by laser sintering. Due to the fast heating and cooling rate, the CNTs are evenly distributed in the metal matrix. The temperature field was calculated by multiphysics simulation considering size effects, including size dependent melting temperature, thermal conductivity, and heat capacity. The SEM, TEM, and XRD were used to understand the laser sintering of CNT integrated nanocomposites. The results proved the feasibility of this technique to synthesize MWNTS integrated metal matrix nanocomposites.

  19. Closed system Fischer-Tropsch synthesis over meteoritic iron, iron ore and nickel-iron alloy. [deuterium-carbon monoxide reaction catalysis

    NASA Technical Reports Server (NTRS)

    Nooner, D. W.; Gibert, J. M.; Gelpi, E.; Oro, J.

    1976-01-01

    Experiments were performed in which meteoritic iron, iron ore and nickel-iron alloy were used to catalyze (in Fischer-Tropsch synthesis) the reaction of deuterium and carbon monoxide in a closed vessel. Normal alkanes and alkenes and their monomethyl substituted isomers and aromatic hydrocarbons were synthesized. Iron oxide and oxidized-reduced Canyon Diablo used as Fischer-Tropsch catalysts were found to produce aromatic hydrocarbons in distributions having many of the features of those observed in carbonaceous chondrites, but only at temperatures and reaction times well above 300 C and 6-8 h.

  20. Iron and manganese removal by using manganese ore constructed wetlands in the reclamation of steel wastewater.

    PubMed

    Xu, Jing-Cheng; Chen, Gu; Huang, Xiang-Feng; Li, Guang-Ming; Liu, Jia; Yang, Na; Gao, Sai-Nan

    2009-09-30

    To reclaim treated steel wastewater as cooling water, manganese ore constructed wetland was proposed in this study for the removal of iron and manganese. In lab-scale wetlands, the performance of manganese ore wetland was found to be more stable and excellent than that of conventional gravel constructed wetland. The iron and manganese concentration in the former was below 0.05 mg/L at hydraulic retention time of 2-5 days when their influent concentrations were in the range of 0.16-2.24 mg/L and 0.11-2.23 mg/L, respectively. Moreover, its removals for COD, turbidity, ammonia nitrogen and total phosphorus were 55%, 90%, 67% and 93%, respectively, superior to the corresponding removals in the gravel wetland (31%, 86%, 58% and 78%, respectively). The good performance of manganese ore was ascribed to the enhanced biological manganese removal with the aid of manganese oxide surface and the smaller size of the medium. The presence of biological manganese oxidation was proven by the facts of good manganese removal in wetlands at chemical unfavorable conditions (such as ORP and pH) and the isolation of manganese oxidizing strains from the wetlands. Similar iron and manganese removal was later observed in a pilot-scale gravel-manganese-ore constructed wetland, even though the manganese ore portion in total volume was reduced from 100% (in the lab-scale) to only 4% (in the pilot-scale) for the sake of cost-saving. The quality of the polished wastewater not only satisfied the requirement for cooling water but also suitable as make-up water for other purposes. PMID:19443107

  1. POLLUTION EFFECTS OF ABNORMAL OPERATIONS IN IRON AND STEEL MAKING. VOLUME II. SINTERING, MANUAL OF PRACTICE

    EPA Science Inventory

    The report is one in a six-volume series considering abnormal operating conditions (AOCs) in the primary section (sintering, blast furnace ironmaking, open hearth, electric furnace, and basic oxygen steelmaking) of an integrated iron and steel plant. Pollution standards, generall...

  2. Magneto-Mineralogical and Physico-Chemical Characterization of the Peña Colorada Iron-Ore, México: Genetic Implications

    NASA Astrophysics Data System (ADS)

    Rivas, M. L.; Alva-Valdivia, L. M.; Urrutia, J.; Gogitchaichvili, A.

    2004-05-01

    Peña Colorada iron-ores represented by massive-disseminated ore and intergranular magnetite ore. Mössbauer spectroscopy shows differences in both magnetite-ores. Magnetite of massive-disseminated ore has a stable structure, with Fe in oxidation state III (Fe2O3) and Fe in oxidation state II (FeO). Magnetite of intergranular ore has a micro-margin of replacement with particular properties, because have radicals (OH-) in positions corresponding to oxygen, shifting alternatively Fe II by Fe III. Chlorite associated to intergranular magnetite is classified as chamosite (berthierine variety). Berthierine presents structural differences by X-ray diffraction at 550 oC temperature loosing its cristallinity becoming amorphous. Differential and gravimetric thermal analyses of berthierine show typical endo-thermal reactions at 430 oC and 510 oC by dehydratation, and endo-thermal reaction at 980 oC by structural change. We propose contact metamorphism and a hydrothermal phase, pursued by disseminated-massive magnetite deposition as the main processes acting in the formation of the Peña Colorada iron-ore deposit. Intergranular ore is sedimentary exhalative origin deposited together with berthierine. Massive-disseminated and intergranular ore have similar geochemical evolution and different conditions of deposit. Curie temperatures are mostly 580 ± 5oC typical of magnetite. Hysteresis parameters indicate that most samples present PSD to MD behavior. AF demagnetization and isothermal remanent magnetization (IRM) acquisition curves show that NRM and laboratory remanence are carried by MD magnetite in iron ores and PSD-SD magnetite in host rocks. Magnetic Force Microscope images for both ore minerals show good and diffuse magnetic domain definition, respectively. Lack of clarity of the intergranular ore image is due to environment, temperature and formation conditions related to magnetostatic changes and magnetocrystalline anisotropy of grains.

  3. Coproduction of clean syngas and iron from woody biomass and natural goethite ore

    Microsoft Academic Search

    Shinji Kudo; Keigo Sugiyama; Koyo Norinaga; Chun-Zhu Li; Tomohiro Akiyama; Jun-ichiro Hayashi

    Conversion of biomass into clean syngas was studied considering application of low-grade iron ore to reforming of tar. Chipped cedar with moisture content of 0.1–10.1wt% was continuously pyrolysed at 550°C, and the nascent volatiles were subjected to reforming at 690–800°C in a bed of mesoporous hematite derived from a type of natural goethite. The yield of heavy tar (b.p.>350°C) decreased

  4. Studies on the influence of a flotation collector reagent on iron ore green pellet properties

    Microsoft Academic Search

    S. P. E. Forsmo; B. M. T. Björkman; P.-O. Samskog

    2008-01-01

    The properties of iron ore green pellets with varying additions of a surface-active flotation collector reagent (Atrac) were studied by small-scale balling. The compression strength and plasticity were measured with a semi-automatic measuring device and the pressure curves were saved and subjected to further mathematical treatment. The green pellet breakage was also filmed with a high-speed camera. Adding Atrac to

  5. Effects of iron-ore mining and processing on metal bioavailability in a tropical coastal lagoon

    Microsoft Academic Search

    Adriana Alves Pereira; Bert van Hattum; Abraham Brouwer; Peter Michiel van Bodegom; Carlos Eduardo Rezende; Wim Salomons

    2008-01-01

    Background, aim, and scope  In water systems, water quality and geochemical properties of sediments determine the speciation of trace metals, metal transport,\\u000a and sediment–water exchange, influencing metal availability and its potential effects on biota. Studies from temperate climates\\u000a have shown that iron-ore mining and tailing wastewaters, besides being a source of trace metals, usually show high levels\\u000a of dissolved ions and

  6. Experimental evaluation of sorptive removal of fluoride from drinking water using iron ore

    NASA Astrophysics Data System (ADS)

    Kebede, Beekam; Beyene, Abebe; Fufa, Fekadu; Megersa, Moa; Behm, Michael

    2014-06-01

    High concentrations of fluoride in drinking water is a public health concern globally and of critical importance in the Rift Valley region. As a low-cost water treatment option, the defluoridation capacity of locally available iron ore was investigated. Residence time, pH, agitation rate, particle size of the adsorbent, sorbent dose, initial fluoride concentration and the effect of co-existing anions were assessed. The sorption kinetics was found to follow pseudo-first-order rate and the experimental equilibrium sorption data fitted reasonably well to the Freundlich model. The sorption capacity of iron ore for fluoride was 1.72 mg/g and the equilibrium was attained after 120 min at the optimum pH of 6. The sorption study was also carried out at natural pH conditions using natural ground water samples and the fluoride level was reduced from 14.22 to 1.17 mg/L (below the WHO maximum permissible limit). Overall, we concluded that iron ore can be used in water treatment for fluoride removal in the Rift Valley region and beyond.

  7. Chelatometric determination of calcium and magnesium in iron ores, slags, anorthosite, limestone, copper-nickel-lead-zinc ores and divers materials.

    PubMed

    Hitchen, A; Zechanowitsch, G

    1980-03-01

    Chelatometric methods for the determination of calcium and magnesium in iron ores, slags, anorthosite, copper-nickel-lead-zinc ores and various other materials are described. Potential interfering elements are masked with triethanolamine and potassium cyanide. In one aliquot calcium is titrated at pH > 12, with calcein and thymolphthalein mixed indicator and in another aliquot calcium and magnesium are titrated in ammonia buffer, with o-cresolphthalein complexone screened with Naphthol Green B as indicator. The results compare favourably with certified values for reference materials of diverse nature. PMID:18962661

  8. On the influence of porosity on the portevin-le chatelier effect in sintered iron

    NASA Astrophysics Data System (ADS)

    Palma, Es

    1996-10-01

    Sintered irons of four different porosities were strained in tension at temperatures between 295 (room temperature) and 873 K. Serrated stress-strain curves and high work hardening in the temperature range from 333 to 693 K, for all porosities, were characteristic of dynamic strain aging. The activation energy for the onset of serration was ±0.82 eV and was independent of porosity. On the contrary, the parameter ? from the relation for dislocation density increased with increasing porosity.

  9. Pressurized chemical-looping combustion of coal with an iron ore-based oxygen carrier

    SciTech Connect

    Xiao, Rui; Song, Min; Zhang, Shuai; Shen, Laihong [School of Energy and Environment, Southeast University, Sipailou No. 2, Nanjing 210096 (China); Song, Qilei [School of Energy and Environment, Southeast University, Sipailou No. 2, Nanjing 210096 (China); Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Lu, Zuoji [School of Energy and Environment, Southeast University, Sipailou No. 2, Nanjing 210096 (China); GCL Engineering Limited, Zhujiang No. 1, Nanjing 210008 (China)

    2010-06-15

    Chemical-looping combustion (CLC) is a new combustion technology with inherent separation of CO{sub 2}. Most of the previous investigations on CLC of solid fuels were conducted under atmospheric pressure. A pressurized CLC combined cycle (PCLC-CC) system is proposed as a promising coal combustion technology with potential higher system efficiency, higher fuel conversion, and lower cost for CO{sub 2} sequestration. In this study pressurized CLC of coal with Companhia Valedo Rio Doce (CVRD) iron ore was investigated in a laboratory fixed bed reactor. CVRD iron ore particles were exposed alternately to reduction by 0.4 g of Chinese Xuzhou bituminous coal gasified with 87.2% steam/N{sub 2} mixture and oxidation with 5% O{sub 2} in N{sub 2} at 970 C. The operating pressure was varied between 0.1 MPa and 0.6 MPa. First, control experiments of steam coal gasification over quartz sand were performed. H{sub 2} and CO{sub 2} are the major components of the gasification products, and the operating pressure influences the gas composition. Higher concentrations of CO{sub 2} and lower fractions of CO, CH{sub 4}, and H{sub 2} during the reduction process with CVRD iron ore was achieved under higher pressures. The effects of pressure on the coal gasification rate in the presence of the oxygen carrier were different for pyrolysis and char gasification. The pressurized condition suppresses the initial coal pyrolysis process while it also enhances coal char gasification and reduction with iron ore in steam, and thus improves the overall reaction rate of CLC. The oxidation rates and variation of oxygen carrier conversion are higher at elevated pressures reflecting higher reduction level in the previous reduction period. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX) analyses show that particles become porous after experiments but maintain structure and size after several cycles. Agglomeration was not observed in this study. An EDX analysis demonstrates that there is very little coal ash deposited on the oxygen carrier particles but no appreciable crystalline phases change as verified by X-ray diffraction (XRD) analysis. Overall, the limited pressurized CLC experiments carried out in the present work suggest that PCLC of coal is promising and further investigations are necessary. (author)

  10. The Effect of Microwave Treatment on Dry Grinding Kinetics of Iron Ore

    Microsoft Academic Search

    S. M. Javad Koleini; K. Barani; B. Rezaei

    2012-01-01

    The effect of microwave treatment on the grinding kinetics of an iron ore was assessed using mono-sized materials of ?2.360 + 2.0 mm, ?1.400 + 1.180 mm, ?1.0 + 0.850 mm, and ?0.355 + 0.300 mm as feed. Microwave-treated samples were kept in a multimode microwave oven with 1100 W input power. The grinding tests were conducted using a laboratory ball mill under identical conditions to allow a comparative analysis of the results.

  11. The Effect of Microwave Treatment upon Dry Grinding Kinetics of Iron Ore

    Microsoft Academic Search

    S. M. Javad Koleini; K. Barani; B. Rezaei

    2011-01-01

    The effect of microwave treatment on the grinding kinetics of an iron ore was assessed using mono-sized materials of ?2.360 + 2.0 mm, ?1.400 + 1.180 mm, ?1.0 + 0.850 mm and ?0.355 + 0.300 mm as feed. Microwave-treated samples were treated in a multimode microwave oven with 1100 W input power. The grinding tests were conducted using a laboratory ball mill under identical conditions to allow a comparative analysis of the results.

  12. Integrated magnetic studies of the El Romeral iron-ore deposit, Chile: implications for ore genesis and modeling of magnetic anomalies

    NASA Astrophysics Data System (ADS)

    Alva-Valdivia, L. M.; Rivas-Sánchez, M. L.; Goguitchaichvili, A.; Urrutia-Fucugauchi, J.; Gonzalez, A.; Vivallo, W.

    2003-08-01

    Mineralogical and rock-magnetic studies of iron ores and host rocks in El Romeral Mine are carried out to characterize the magnetic mineralogy and the processes that affect the natural remanent magnetization during emplacement and evolution of the iron-ore deposit. Extremely important is the identification of magnetic mineralogical composition (magnetite and/or titanomagnetite, hematite and/or titanohematite, and titanomaghemite) and grain size. These data permit investigation of magnetic domain state and magnetization acquisition processes and to assess their significance as a source of magnetic anomalies. Chemical remanent magnetization (CRM) seems to be present in most of investigated ore and wall-rock samples, substituting completely or partially the original thermoremanent magnetization (TRM). Magnetite (or Ti-poor titanomagnetite) and titanohematite are commonly found in the ores. Although hematite may carry a stable CRM, no secondary components are detected above 580 °C, which probably attests that oxidation occurred soon after the extrusion and cooling of the ore-bearing magma. The microscopy study under reflected light shows that magnetic carriers are mainly titanomagnetite with significant amounts of ilmenite-hematite minerals. Magmatic titanomagnetite, found in igneous rocks, shows trellis texture, which is compatible with high temperature (deuteric) oxy-exsolution processes. Hydrothermal alteration in ore deposits is indicated by goethite and hematite oxide minerals. Grain sizes range from a few microns to >100 ?m, and possible magnetic states from single to multidomain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and isothermal remanent magnetization acquisition suggest a predominance of spinels as magnetic carriers, most probably titanomagnetites with low-Ti content. For quantitative modeling of the magnetic anomaly, we used data on bulk susceptibility and natural remanent intensity for quantifying the relative contributions of induced and remanent magnetization components, and this allows greater control of the geometry of source bodies. The position and geometry of these magnetic sources are shown as ENE-striking tabular bodies, one steeply inclined (75°) to the south and another lying horizontal.

  13. Phosphorus retention capacity of iron-ore and blast furnace slag in subsurface flow constructed wetlands.

    PubMed

    Grüneberg, B; Kern, J

    2001-01-01

    The suitability of iron-ore and blast furnace slag for subsurface flow (SSF) constructed wetlands was studied over a period of four months. Dairy farm wastewater (TP 45 mg l(-1)) was percolated through buckets planted with reed (volume 9.1 l; hydraulic load 151 m(-2) d(-1)). One group of buckets was kept under aerobic conditions and the other group under anaerobic conditions, monitored by continuous redox potential measurements. Even at high mass loading rates of 0.65 g P m(-1) d(-1) the slag provided 98% removal efficiency and showed no decrease in performance with time. However, phosphorus fractionation data indicate that the high phosphorus retention capacity under aerobic conditions is to a great extent attributable to unstable sorption onto calcium compounds (NH4Cl-P). Phosphorus sorption of both the slag (200 microg P g(-1)) and the iron-ore (140 microg P g(-1)) was promoted by predominantly anaerobic conditions due to continuous formation of amorphous ferrous hydroxides. None of the substrates had adverse affects on reed growth. PMID:11804160

  14. Magnetometric surveys over some iron-ore occurrences in the Eastern Ghats belt of Godavari Districts, Andhra Pradesh

    NASA Astrophysics Data System (ADS)

    Bhaskara Rao, V.; Lakshmipathi Raju, A.

    1984-07-01

    Iron-ore with magnetite as the chief ore mineral occurs in the Precambrians of Eastern Ghats. Vertical magnetometric surveys were carried out to delineate some of the ore bands, in the Ghats belt of Godavari Districts, Andhra Pradesh, around Addatigala, Devipatnam and Tekuru. Interpretation of the magnetic anomalies was based on the tabular models. Ore bands are at shallow depths of around 5m. The deduced inclinations of magnetisation suggest that the magnetisation is largely remanent. The intensities of magnetisation are in the range of 5 to 10·5×10-3 emu and agree well with the laboratory measurements on the ore samples. At Devipatnam and Tekuru the magnetic background seems to be high. At Tekuru the ore band appears to be very limited in depth extent. The limited depth extent coupled with high magnetic background explains the anomaly which is not so prominent. It is concluded that in such areas, it is only the high grade magnetite ore bands of considerable depth extent that can be successfully delineated by the magnetic method.

  15. Mineralogy and trace-element geochemistry of the high-grade iron ores of the Águas Claras Mine and comparison with the Capão Xavier and Tamanduá iron ore deposits, Quadrilátero Ferrífero, Brazil

    NASA Astrophysics Data System (ADS)

    Spier, Carlos Alberto; de Oliveira, Sonia Maria Barros; Rosière, Carlos Alberto; Ardisson, José Domingos

    2008-02-01

    Several major iron deposits occur in the Quadrilátero Ferrífero (QF), southeastern region of Brazil, where metamorphosed and heterogeneously deformed banded iron formation (BIF) of the Cauê Formation, regionally called itabirite, was transformed into high- (Fe >64%) and low-grade (30% < Fe < 64%) hematite ores. Based on their mineralogical composition, three major types of itabirites occur in the QF: siliceous, dolomitic, and amphibolitic itabirite. Unlike other mines in the QF, the Águas Claras Mine contained mainly high-grade ores hosted within dolomitic itabirite. Two distinct types of high-grade ore occurred at the mine: soft and hard. The soft ore was the most abundant and represented more than 85% of the total ore mined until it was mined out in 2002. Soft and hard ores consist essentially of hematite, occurring as martite, anhedral to granular/tabular hematite and, locally, specularite. Gangue minerals are rare, consisting of dolomite, sericite, chlorite, and apatite in the hard and soft ores, and Mn-oxides and ferrihydrite in the soft ore where they are concentrated within porous bands. Chemical analyses show that hard and soft ores consist almost entirely of Fe2O3, with a higher amount of detrimental impurities, especially MnO, in the soft ore. Both hard and soft ores are depleted in trace elements. The high-grade ores at the Águas Claras Mine have at least a dual origin, involving hypogene and supergene processes. The occurrence of the hard, massive high-grade ore within “fresh” dolomitic itabirite is evidence of its hypogene origin. Despite the contention about the origin of the dolomitic itabirite (if this rock is a carbonate-rich facies of the Cauê Formation or a hematite-carbonate precursor of the soft high-grade ore), mineralogical and geochemical features of the soft high-grade ore indicate that it was formed by leaching of dolomite from the dolomitic itabirite by meteoric water. The comparison of the Águas Claras, Capão Xavier and Tamanduá orebodies shows that the original composition of the itabiritic protore plays a major role in the genesis of high- and low-grade soft ores in the QF. Under the same weathering and structural conditions, the dolomitic itabirite is the more favorable to form high-grade deposits than siliceous itabirite. Field relations at the Águas Claras and Capão Xavier deposits suggest that it is not possible to form huge soft high-grade supergene deposits from siliceous itabirite, unless another control, such as impermeable barriers, had played an important role. The occurrence in the Tamanduá Mine of a large, soft, high-grade orebody formed from siliceous itabirite and closely associated with hypogene hard ore suggests that large, soft, high-grade orebodies of the Quadrilátero Ferrífero, which occur within siliceous itabirite, have a hypogene contribution in their formation.

  16. Iron ore beneficiation using roll-type high-intensity electric field separators

    SciTech Connect

    Morar, R.; Iuga, A.; Muntean, O. [Technical Univ. of Cluj-Napoca (Romania). Electrical Engineering Dept.] [Technical Univ. of Cluj-Napoca (Romania). Electrical Engineering Dept.; Cuglesan, I. [Inst. of Research and Development for the Mining Industry, Cluj-Napoca (Romania)] [Inst. of Research and Development for the Mining Industry, Cluj-Napoca (Romania); Dascalescu, L. [Inst. Univ. de Technologie d`Angouleme (France). Lab. de Technologies Electriques et Electroniques Avancees] [Inst. Univ. de Technologie d`Angouleme (France). Lab. de Technologies Electriques et Electroniques Avancees

    1999-01-01

    This paper aims to demonstrate that high-intensity electric fields can be employed for the separation of artificial magnetite processed from an iron mineral containing siderite FeCO{sub 3} and ankerite (FeCaMg)CO{sub 3}. All the tests were carried out on a roll-type laboratory separator (roll diameter: 250 mm; roll speed: 175 r/min), provided with an over-tray heater, to ensure the thermal conditioning of the samples at +120 C, and a system of high-voltage electrodes, consisting of a needle-type corona electrode and either a second corona electrode or a tubular (electrostatic) electrode. The samples were collected from the technological process presently employed for the beneficiation of the iron ore deposit at Teliuc, Romania. The grain size was typically in the 0.09--0.315-mm range. Separation in high-intensity electric field ensured the increase of the Fe content in the samples from about 35--55%, for an iron recovery of up to 80%. This paper discusses these results in relation to the mineralogical characteristics of the samples and concludes that electrostatic separation could be employed either as an additional operation in an existing technological process, or as an alternative to the currently employed magnetic separation. Pilot-plant tests are needed prior to industry application.

  17. A risk assessment for exposure to grunerite asbestos (amosite) in an iron ore mine

    PubMed Central

    Nolan, R. P.; Langer, A. M.; Wilson, Richard

    1999-01-01

    The potential for health risks to humans exposed to the asbestos minerals continues to be a public health concern. Although the production and use of the commercial amphibole asbestos minerals—grunerite (amosite) and riebeckite (crocidolite)—have been almost completely eliminated from world commerce, special opportunities for potentially significant exposures remain. Commercially viable deposits of grunerite asbestos are very rare, but it can occur as a gangue mineral in a limited part of a mine otherwise thought asbestos-free. This report describes such a situation, in which a very localized seam of grunerite asbestos was identified in an iron ore mine. The geological occurrence of the seam in the ore body is described, as well as the mineralogical character of the grunerite asbestos. The most relevant epidemiological studies of workers exposed to grunerite asbestos are used to gauge the hazards associated with the inhalation of this fibrous mineral. Both analytical transmission electron microscopy and phase-contrast optical microscopy were used to quantify the fibers present in the air during mining in the area with outcroppings of grunerite asbestos. Analytical transmission electron microscopy and continuous-scan x-ray diffraction were used to determine the type of asbestos fiber present. Knowing the level of the miner’s exposures, we carried out a risk assessment by using a model developed for the Environmental Protection Agency. PMID:10097051

  18. An Innovative Magnetic Charging Chute to Improve Productivity of Sinter Machine at Rourkela Steel Plant

    NASA Astrophysics Data System (ADS)

    Selvam, Sambandham Thirumalai; Chaudhuri, Subhasis; Das, Arunaba; Singh, Mithilesh Kumar; Mahanta, H. K.

    Sintering is a process in sinter machine for agglomeration of iron ore and other raw material fines into a compact porous mass, i.e., sinter, used in Blast Furnaces as an iron bearing input charge material for hot metal production. 'Permeability' of sinter-bed on sinter machine i.e., the porosity in sinter-bed of charged materials, facilitates atmospheric air passes from the top to bottom across the depth of sinter-bed, when suction created from the bottom of the bed, for efficient heat carry over from top to bottom of the bed for complete burning of charged materials for effective sintering process controls the productivity of the sinter machine. The level of 'permeability' in sinter-bed is depending upon the effectiveness of 'charging chute' in size-wise 'segregation' of charge materials across the depth in sinter-bed, achieved due to differences in the sliding velocities of particles during charging into the moving sinter-bed. The permeability achieved by the earlier conventional 'charging chute' was limited due to its design and positional constraints in sinter machine. Improving the productivity of sinter machine, through increased permeability of sinter bed is successfully achieved through implementation of an innovatively designed and developed, "Magnetic Charging Chute" at Sinter Plant no. 2 of Rourkela Steel Plant. The induced magnetic force on the charged materials while the charge materials dropping down through the charge chute has improved the permeability of sinter bed through an unique method of segregating the para-magnetic materials and the finer materials of the charge materials to top layer of sinter bed along with improved size-wise segregation of charge materials. This has increased the productivity of the sinter machine by 3% and also reduced the solid fuel consumption i.e., coke breeze in input charge materials by 1 kg/t of sinter.

  19. A characteristic feature of the solution of carbon in iron during the initial stage of sintering of iron-graphite composites

    Microsoft Academic Search

    O. V. Roman; S. Basu; T. K. Garkavaya; G. N. Dubrovskaya

    1974-01-01

    In the manufacture of iron-graphite composite parts by the powder metallurgy technique the sintering operation usually lasts from 40 to 120 min, a period of time enabling all processes to become stabilized and ensuring that the resultant structure of the material is comparatively stable. In contrast to this, hot pressing and particularly dynamic hot pressing and also analogous processes such

  20. The effects of iron ore dust on mangroves in Western Australia: Lack of evidence for stomatal damage

    Microsoft Academic Search

    E. I. Paling; G. Humphries; I. McCardle; G. Thomson

    2001-01-01

    Anecdotal evidence suggests that iron ore dust derived from industrialshiploading activities in north-western Australia may be more injurious tomangroves than is naturally-derived dust, because of its more angularstructure and presumed ability to damage stomatal cells. Abaxial hairs onthe most common mangrove, Avicennia marina (Forfk). Vierh., havebeen thought to exacerbate this effect through trapping and retaining dust.This study examined this hypothesis.

  1. THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY

    SciTech Connect

    Gary Gartenberg

    2003-12-01

    This report represents the thirteenth Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this semi annual reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the Green Pond Mine site at the Township's Jacobs Road Compost Storage Facility, construction was completed during this reporting period and surface monitoring began. Surface monitoring was conducted periodically at the Mt. Hope Road subsidence work area and adjacent areas after the January 2000 construction effort.

  2. THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TONWSHIP, NEW JERSEY

    SciTech Connect

    Gary Gartenberg

    2003-02-01

    This report represents the tenth Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government-Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the Green Pond Mine site at the Township Compost Storage Facility, engineering continued during this reporting period toward development of the Construction Plans and Technical Specifications for the remediation work. At the Mt. Hope Road subsidence, surface monitoring was conducted periodically at the work area and adjacent areas after the January 2000 construction effort.

  3. A comparative study of the wear behaviour of sintered and laser surface melted AISI M42 high speed steel diluted with iron

    Microsoft Academic Search

    R. Colaço; E. Gordo; E. M. Ruiz-Navas; M. Otasevic; R. Vilar

    2006-01-01

    Powders of AISI M42 high-speed steel (HSS) were blended with different proportions of water-atomised iron powders. The powders were subsequently submitted to uniaxial pressing and then divided in three lots. The first was submitted to sintering, the second was submitted to sintering plus laser surface melting (LSM) and the third was submitted to sintering plus LSM plus double tempering at

  4. Effect of the catalyzing combustion of coke breeze on the energy saving in sinter process

    Microsoft Academic Search

    De-qing Zhu; Guan-zhou Qiu; Tao Jiang; Bao-jun Zhu

    2001-01-01

    The mechanism of additive ZC-1 for catalyzing combustion of coke breeze in sintering of iron ore fines was studied by using\\u000a X-ray Diffraction, TGA and GC(Gas Chromatographer), by which energy saving was achieved on sinter pot test. The results show\\u000a that the distance between cleavage planes is enlarged and the ?-electrons are re-distributed because of the insertion of cations\\/molecules\\u000a of

  5. Petrogenesis and Fluid inclusions of the Band-e Narges skarn iron ore, Central Iran

    NASA Astrophysics Data System (ADS)

    Nazari, Maliheh; Lotfi, Mohammad; Omran, Neematollah R. N.

    2015-04-01

    The Band Narges iron deposit is located approximately 205km NE of Isfhan and is a small area in the NE of Urumieh- Dokhtar Magmatic Arc, Iran. The skarn hosted in a Cretaceous limestone, intruded by granite and granodiorite. The calcic skarn has experienced two stages of metamorphism: 1) prograde stage, which include endoskarn and exoskarnfacies with clinopyroxene, garnet, scapolite and albite mineralization, and 2) retrograde stage which produced actinolite, epidote, chlorite and apatite assemblage through retrograde alteration. The ore minerals in Band-e Nargesskarn are magnetite, with minor chalcopyrite, pyrrhotite and pyrite. Gange minerals are predominantly diopside, andradite, epidote, chlorite, quartz and calcite. Micro-thermometric measurements yield a homogenization temperature range for skarn alteration of 414 to 448°C, with a salinity of 11 to 13.186 wt.%NaCl equivalent. Fluid inclusions in calcite associated with mineralization generally consist of a vapor bubble and a liquid phase with a rare occurrence of three-phase inclusions. Homogenization temperatures for two phase inclusions vary from 168 °C to 203 °C with a salinity of 0.5 to 2 wt% NaCl equivalent. Homogenization of three phase inclusions was observed between 162 °C to 278 °C with salinity of 4 to 23 wt.%NaCl equivalent. The high-temperature and high-salinity of fluids indicate magmatic nature of the trapped fluids within progradeskarn mineral assemblages in contrast the fluids with lower temprature and lower salinity displaying a possible meteoric source within the retrograde skarn assemblages. Therefore moderate temperature and high-salinity fluids could infer to possible isothermal mixing between the fluids. Key word:Skarn,Band-e Narges,fluid inclusion

  6. THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY

    SciTech Connect

    Gary Gartenberg, P.E., P.P.

    2001-04-01

    This report represents the seventh Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the Green Pond Mine site at the Township Compost Storage Facility, research and preliminary design was performed during this reporting period toward development of the engineering plans and Technical Specifications for the remediation work. At the White Meadow Mine site, the remediation project was conducted last reporting period by others, out of the responsibility of Rockaway Township under this Cooperators Agreement. At the Mt. Hope Road subsidence, surface monitoring was conducted at the work area and adjacent areas after the January 2000 construction effort.

  7. THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY

    SciTech Connect

    Gary Gartenberg, P.E., P.P.

    1999-10-01

    This report represents the fourth Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. During this reporting period the Engineering Design for remediation of the surface safety hazards associated with the White Meadow Mine was completed. Construction Plans and Technical Specifications were completed and competitive bids were solicited by the Township for completion of the work. The electrical resistivity survey analysis and report was completed for the Green Pond Mines site at the Township Compost Storage Facility. The geophysical survey results confirmed evidence of abandoned mining activity at the Green Pond Mine site which was previously identified. During this reporting period, the time frame of the Cooperative Agreement between the Township and the Department of Energy was extended. An additional site of subsidence with in the Township related to abandoned mining activity at Mount Hope Road was selected by Rockaway Township to be considered for remediation and inclusion under the Cooperative Agreement.

  8. The Remediation of Abandoned Iron Ore Mine Subsidence in Rockaway Township, New Jersey

    SciTech Connect

    Gartenberg, Gary; Poff, Gregory

    2010-06-30

    This report represents the twenty-seventh and Final Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this last reporting period ending June 30, 2010 and a summary of the work accomplished since the agreement inception in 1997. This report is issued as part of the project reporting provisions set forth in the Cooperatorâ??s Agreement between the United States Government - Department of Energy, and Rockaway Township. The purpose of the Cooperatorâ??s Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800â??s, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the Green Pond Mine site at the Townshipâ??s Jacobs Road Compost Storage Facility, surface monitoring continued after completion of construction in September 2003. Surface monitoring was conducted periodically at the Mt. Hope Road subsidence work area and adjacent areas after the January 2000 construction effort. In March 2007, a seventh collapse occurred over a portion of the White Meadow Mine in a public roadway at the intersection of Iowa and Erie Avenues in Rockaway Township. After test drilling, this portion of the mine was remediated by drilling and grouting the stopes.

  9. THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY

    SciTech Connect

    Gary Gartenberg, P.E., P.P.

    2001-04-01

    This report represents the sixth Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the White Meadow Mine site, after amended specifications were prepared and continued negotiations took place with the Property Owner, the property ownership was transferred during the reporting period. As a result in the change in property ownership, the remediation project was then to be done by the new Property Owner out of the responsibility of Rockaway Township under this Cooperators Agreement. At the Mt. Hope Road subsidence, surface monitoring was conducted at the work area and adjacent areas after the January 2000 construction effort. At the Green Pond Mine site at the Township Compost Storage Facility, no additional field work was undertaken during this reporting period subsequent to the previous completion of the geophysical survey. With the termination of the White Meadow Mine project, work began toward development of a remedial design for the Green Pond Mines.

  10. Laser sintering of magnesia with nanoparticles of iron oxide and aluminum oxide

    NASA Astrophysics Data System (ADS)

    García, L. V.; Mendivil, M. I.; Roy, T. K. Das; Castillo, G. A.; Shaji, S.

    2015-05-01

    Nanoparticles of iron oxide (Fe2O3, 20-40 nm) and aluminum oxide (Al2O3, 50 nm) were mixed in different concentrations (3, 5 and 7 wt%) in a magnesium oxide (MgO) matrix. The mixture pellet was irradiated with 532 nm output from a Q-switched Nd:YAG laser using different laser fluence and translation speed for sintering. The refractory samples obtained were analyzed using X-ray diffraction technique, scanning electron microscopy and X-ray photoelectron spectroscopy. The results showed that the samples irradiated at translation speed of 110 ?m/s and energy fluence of 1.7 J/cm2 with a concentration of 5 and 7 wt% of Fe2O3 presented the MgFe2O4 spinel-type phase. With the addition of Al2O3 nanoparticles, at a translation speed of 110 ?m/s and energy fluence of 1.7 J/cm2, there were the formations of MgAl2O4 spinel phase. The changes in morphologies and microstructure due to laser irradiation were analyzed.

  11. The influence of the density of a gas–solid fluidized bed on the dry dense medium separation of lump iron ore

    Microsoft Academic Search

    Jun Oshitani; Tetsuya Kawahito; Mikio Yoshida; Kuniaki Gotoh; George V. Franks

    A gas–solid fluidized bed was used for dry dense medium separation of lump iron ore particles based on their floating and sinking in the fluidized bed. The density of the bed was adjusted to different values using mixtures of zircon sand and iron powder as the fluidized media. Float–sink experiments using 30mm diameter density adjusted spheres in the range of

  12. Banded Iron Formations from the Eastern Desert of Egypt: A new type of Ore? KHALIL, Khalil Isaac1 and EL-SHAZLY, Aley K.2

    E-print Network

    El-Shazly, Aley

    Banded Iron Formations from the Eastern Desert of Egypt: A new type of Ore? KHALIL, Khalil Isaac1 and EL-SHAZLY, Aley K.2 1 Department of Geology, University of Alexandria, Egypt 2 Geology Department localities in an area approximately 30,000 km2 within the eastern desert of Egypt. With the exception

  13. Production of free radicals arising from the surface activity of minerals and oxygen. Part I. Iron mine ores

    SciTech Connect

    Costa, D.; Guignard, J.; Zalma, R.; Pezerat, H. (Universite P. et M. Curie, Paris (France))

    1989-12-01

    The excess incidence of lung cancers observed in many metal mines probably is not only correlated with radioactivity but also with the inhaled dusts. In an attempt to determine a possible mechanism of carcinogenicity related to the surface activity of dusts, using the spin-trapping agent and ESR spectroscopy, one can demonstrate that some mineral dusts from iron ore mines are very active in an oxidative process in aqueous medium, implying the formation of radical oxygen species on reducing surface sites of the solid. This reducing surface activity of the dusts depends on the presence of Fe{sup 2+} ion in the lattice and on the process of activation and passivation of the surface sites. The more simple process of activation is the dissolution of the oxidized coating on the particle surface. Among the oxides, oxyhydroxides, carbonates, and silicates, the magnesium-iron phyllosilicates (chlorite, biotite, berthierine) appear the most active. The siderite FeCO{sub 3} is also active, but the iron oxides and oxyhydroxides are generally nonactive.

  14. Os isotopic composition of steels: Constraints on sources of Os in steel & crustal isotopic evolution of iron ores

    NASA Astrophysics Data System (ADS)

    Chatterjee, R. N.; Lassiter, J. C.

    2013-12-01

    Metal contamination during sample processing is a potential concern in Os-isotope studies. We examined Os concentrations and Os isotopes in industrial steels. Samples include high Cr stainless steels (>10.5% Cr), low alloy steels (>=92% Fe) and high alloy steels (<92% Fe). The chief components used to make steel are iron ore, chromites and coke. Coke is derived from coals that have low Os concentration (~36 ppt) [1]. Chromites in steels are mined from chromitites, which have high average Os concentrations and mantle-like 187Os/188Os ratios (~88 ppb Os, 187Os/188Os ? 0.127×24) [2]. Iron ores used in US steel manufacturing derive chiefly from magnetites mined from iron-bearing formations such as Banded Iron Formations (BIF), which have median Os concentration of ~4.8 ppb and radiogenic 187Os/188Os ? 0.358×388 [3]. Os concentrations in the measured steels span a wide range, from 0.03 to 22 ppb. The 187Os/188Os ratios vary from 0.144-4.12. Such high Os concentrations and radiogenic isotopic compositions confirm that metal contamination can affect Os-isotope compositions during sample processing, particularly for low-[Os] samples. There is no correlation between C and Os concentration in steel, indicating that coke is not a major Os source in steels. Os concentrations in steels are positively correlated with Cr content, suggesting that chromite-derived Os dominates the Os budget in stainless steels. 187Os/188Os is negatively correlated with Cr content, ranging from 0.144-0.195 in high-Cr (>10.5 % Cr) steels but from 0.279-4.12 in low-Cr steels. In addition, there is a positive correlation between 1/Os and 187Os/188Os, consistent with two-component mixing of Os derived from magnetite ore and chromites. Lower Os concentrations in steels than expected from simple mixing of magnetite and chromitite suggest some volatile Os loss during smelting. Although the current data is limited, the 186Os-187Os trend defined by the steel analyses can be utilized to extrapolate compositions of the end-member chromite and BIF components. 186Os/188Os values in steels range from 0.119830×5 to 0.119842×42, indistinguishable from the upper mantle. Extrapolation of the 186Os-187Os trend to 187Os/188Os values typical for chromites results in an estimated 186Os/188Os value of 0.119832×4, within error of values previously reported for chromites [4,5]. Extrapolation of the chromite-steel trend to the highly radiogenic (continental crust-like) 187Os values found in BIFs results in much greater uncertainty, but the extrapolated value (0.119834×11) is also indistinguishable from the upper mantle. We estimate an upper bound for the initial ?186Os of the 1.8 Ga BIF source of magnetite ore of ~0.3, similar to initial ?186Os in black shales (0.3-0.5) and freshwater Mn-nodule (1.6), but lower than in loess (1-2.4) [6]. Aqueous deposits and precipitates may sample Os derived from crustal sources with systematically lower time-integrated Pt/Os than the sources for loess. [1] Baioumy H.M et al., Chem Geo 2011 [2] Walker R.J et al., GCA 2002 [3] Ripley E.M et al., Chem Geo 2008 [4] Walker R.J et al., EPSL 2005 [5] Brandon A.D et al., Science 1998 [6] McDaniel D.K et al., GCA 2004

  15. Monitoring Sintering Burn-Through Point Using Infrared Thermography

    PubMed Central

    Usamentiaga, Rubén; Molleda, Julio; Garcia, Daniel F.; Bulnes, Francisco G.

    2013-01-01

    Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burn-through point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process. PMID:23939585

  16. Antifriction properties of sintered iron with additions of carbon, silicon, boron, and titanium

    Microsoft Academic Search

    V. E. Oliker; A. S. Klimanov; G. A. Bovkun

    1987-01-01

    Cast-iron eutectic alloys are one of the most common contemporary structural materials [i]. Good mechanical properties of these alloys depend in many respects on their structural properties which are characterized by the presence of strongly interlinked structural components of the iron matrix and hard inclusions (carbides and borides) which possess high hardness and wear resistance [2, 3]. Recently, a large

  17. Rare earth elements, S and Sr isotopes and origin of barite from Bahariya Oasis, Egypt: Implication for the origin of host iron ores

    NASA Astrophysics Data System (ADS)

    Baioumy, Hassan M.

    2015-06-01

    Based on their occurrences and relation to the host iron ores, barites are classified into: (1) fragmented barite occurs as pebble to sand-size white to yellowish white barite along the unconformity between the Bahariya Formation and iron ores, (2) interstitial barite is present as pockets and lenses of large and pure crystals inside the iron ores interstitial barite inside the iron ores, and (3) disseminated barite occurs at the top of the iron ores of relatively large crystals of barite embedded in hematite and goethite matrix. In the current study, these barites have been analyzed for their rare earth elements (REE) as well as strontium and sulfur isotopes to assess their source and origin as well as the origin of host iron ores. Barite samples from the three types are characterized by low ?REE contents ranging between 12 and 21 ppm. Disseminated barite shows relatively lower ?REE contents (12 ppm) compared to the fragmented (19 ppm) and interstitial (21 ppm) barites. This is probably due to the relatively higher Fe2O3 in the disseminated barite that might dilute its ?REE content. Chondrite-normalized REE patterns for the three barite mineralizations exhibit enrichment of light rare earth elements (LREE) relative to heavy rare earth elements (HREE) as shown by the high (La/Yb)N ratios that range between 14 and 45 as well as pronounced negative Ce anomalies varying between 0.03 and 0.18. The 87Sr/86Sr ratios in the analyzed samples vary between 0.707422 and 0.712237. These 87Sr/86Sr values are higher than the 87Sr/86Sr ratios of the seawater at the time of barite formation (Middle Eocene with 87Sr/86Sr ratios of 0.70773 to 0.70778) suggesting a contribution of hydrothermal fluid of high Sr isotope ratios. The ?34S values in the analyzed barites range between 14.39‰ and 18.92‰. The lower ?34S ratios in the studied barites compared with those of the seawater at the time of barite formation (Middle Eocene with ?34S ratios of 20-22‰) is attributed to a possible contribution of hydrothermal fluid of low ?34S values that lowered the ?34S values in the studied barites. Rare earth elements distribution and patterns, as well as strontium and sulfur isotopes suggest a mixing of seawater and a hydrothermal fluid as possible sources for barite mineralizations in the Bahariya Oasis. The seawater source is suggested from the low Ce/La ratios, "V" shape of the rare earth patterns and pronounced negative Ce anomalies. On the other hand, the hydrothermal fluid contribution is evident from the low concentrations of rare earth and the deviation in both S and Sr isotopic compositions from those of the seawater during the time of barites formation (Middle Eocene). The relatively heterogeneous Sr and S isotope ratios among the studied barites suggest the Bahariya Formation and Basement Complex as possible sources of the hydrothermal fluids. The similarity in the REE as well as S and Sr isotopic compositions of the three types of barite suggest that they form simultaneously. As the geology and occurrence of the barites suggest a genetic relationship between these barites and the host iron ores, the mixed seawater and hydrothermal sources model of the barites is still applicable for the source of the host iron ores.

  18. Implications of Pb isotope signatures of rocks and iron oxide Cu-Au ores in the Candelaria-Punta del Cobre district, Chile

    Microsoft Academic Search

    Robert Marschik; Massimo Chiaradia; Lluís. Fontboté

    2003-01-01

    Lead isotope ratios of ores of the Candelaria-Punta del Cobre iron oxide Cu-Au deposits and associated Early Cretaceous volcanic and batholithic rocks have been determined. For the igneous rocks, a whole-rock acid attack technique based on the separate analyses of a leachate and the residual fraction of a sample was used. The lead isotope systematics of leachate–residue pairs are significantly

  19. Preparation and characterization of novel glass-ceramic tile with microwave absorption properties from iron ore tailings

    NASA Astrophysics Data System (ADS)

    Yao, Rui; Liao, SongYi; Dai, ChangLu; Liu, YuChen; Chen, XiaoYu; Zheng, Feng

    2015-03-01

    A novel glass-ceramic tile consisting of one glass-ceramic layer (GC) attaining microwave absorption properties atop ceramic substrate was prepared through quench-heat treatment route derived from iron ore tailings (IOTs) and commercial raw materials (purity range 73-99%). X-ray diffraction (XRD), SEM, Energy dispersive X-ray spectroscopy (EDS), Fourier transform infrared spectroscopy (FTIR), Physical property measurement system (PPMS) and Vector network analyzer (VNA) measurements were carried out to investigate phase, microstructure, magnetic and microwave absorption aspects of the glass-ceramic layer. Roughly 80.6±1.7 wt% borosilicate glass and 19.4±1.7 wt% spinel ferrite with chemical formula of (Zn2+0.17Fe3+0.83)[Fe3+1.17Fe2+0.06Ni2+0.77]O4 were found among the tested samples. Absorption of Electromagnetic wave by 3 mm thick glass-ceramic layer at frequency of 2-18 GHz reached peak reflection loss (RL) of -17.61 dB (98.27% microwave absorption) at 10.31 GHz. Altering the thickness of the glass-ceramic layer can meet the requirements of different level of microwave absorption.

  20. Sintering of powder mixtures and the growth of ferrous powder metallurgy

    Microsoft Academic Search

    K. S Narasimhan

    2001-01-01

    Advances in the understanding of sintering of powder mixtures contributed significantly to the growth of ferrous powder metallurgy industry. Solid-state sintering and liquid-phase activated sintering play an important role in the sintering of powder mixtures. In this paper, sintering of iron powder with graphite; iron powder with copper and graphite; iron powder with nickel and graphite; iron powder with phosphorus;

  1. Application of the genetic algorithm to estimate the parameters related to the kinetics of the reduction of the iron ore, coal mixture

    SciTech Connect

    Kumar, A.; Roy, G.G. [Indian Institute of Technology, Kharagpur (India)

    2005-12-01

    A novel methodology has been developed to calculate the kinetic parameters associated with reduction of ore-coal composite mixtures and to describe the time course of reduction of hematite to iron. The empirical parameters, namely, the three sets of activation energies and frequency factors, have been estimated by employing an evolutionary optimization tool, the genetic algorithm (GA). The model prediction matches well with the experimental literature data. The estimated activation energies are higher than the corresponding intrinsic values, indicating the role of heat transfer in the process.

  2. Diffusion chromizing of sintered steels

    Microsoft Academic Search

    F. G. Lovshenko; L. S. Lyakhovich; V. T. Vysotskii; Z. M. Lovshenko

    1976-01-01

    The object of the work described below was to study the process of diffusion chromizing of steels produced by sintering iron-graphite composites and to determine some physicomechaniea l properties of sintered steels subjected to this treatment. As starting materials PZh2M2 iron powder* and powdered ZKB pencil-grade graphite were used. Sintering was performed for 2 h at 1150~ in a dissociated

  3. Ore Minerals

    NSDL National Science Digital Library

    Dexter Perkins

    This three part lab introduces sulfides and other ore minerals. Part one - Ore Minerals: Students fill in a table giving the metal, formula, and mineral group of several ore minerals. Part two - Box of Rocks: Students examine trays of ore minerals and record their physical properties, composition, habit, occurence, economic value, and use and answer questions about color, luster, density, transparency, and availability. Part three - Famous Digs: Students answer a series of questions related to famous ore deposits.

  4. New Process of Pellets-Metallized Sintering Process (PMSP) to Treat Zinc-Bearing Dust from Iron and Steel Company

    NASA Astrophysics Data System (ADS)

    Chun, Tiejun; Zhu, Deqing

    2015-02-01

    An innovative process of pellets-metallized sintering process (PMSP) to prepare pre-reduced ironmaking burden using zinc-bearing dust has been developed. The pre-reduced sinter product, assaying 60.53 pct Fe with the metallization degree of 45.23 pct, and the Zn and Pb content of 0.18 and 0.02 pct with the removal rate of 92.78 and 96.37 pct were obtained at the productivity of 0.471 t m-2 h-1 and tumble index of 81.31 pct. PMSP has opened a new way to utilize the zinc-bearing dust efficiently.

  5. Assessment of Vegetation Establishment on Tailings Dam at an Iron Ore Mining Site of Suburban Beijing, China, 7 Years After Reclamation with Contrasting Site Treatment Methods

    NASA Astrophysics Data System (ADS)

    Yan, Demin; Zhao, Fangying; Sun, Osbert Jianxin

    2013-09-01

    Strip-mining operations greatly disturb soil, vegetation and landscape elements, causing many ecological and environmental problems. Establishment of vegetation is a critical step in achieving the goal of ecosystem restoration in mining areas. At the Shouyun Iron Ore Mine in suburban Beijing, China, we investigated selective vegetation and soil traits on a tailings dam 7 years after site treatments with three contrasting approaches: (1) soil covering (designated as SC), (2) application of a straw mat, known as "vegetation carpet", which contains prescribed plant seed mix and water retaining agent (designated as VC), on top of sand piles, and (3) combination of soil covering and application of vegetation carpet (designated as SC+VC). We found that after 7 years of reclamation, the SC+VC site had twice the number of plant species and greater biomass than the SC and VC sites, and that the VC site had a comparable plant abundance with the SC+VC site but much less biodiversity and plant coverage. The VC site did not differ with the SC site in the vegetation traits, albeit low soil fertility. It is suggested that application of vegetation carpet can be an alternative to introduction of topsoil for treatment of tailings dam with fine-structured substrate of ore sands. However, combination of topsoil treatment and application of vegetation carpet greatly increases vegetation coverage and plant biodiversity, and is therefore a much better approach for assisting vegetation establishment on the tailings dam of strip-mining operations. While application of vegetation carpet helps to stabilize the loose surface of fine-structured mine wastes and to introduce seed bank, introduction of fertile soil is necessary for supplying nutrients to plant growth in the efforts of ecosystem restoration of mining areas.

  6. Ore metals through geologic history.

    PubMed

    Meyer, C

    1985-03-22

    The ores of chromite, nickel, copper, and zinc show a wide distribution over geologic time, but those of iron, titanium, lead, uranium, gold, silver, molybdenum, tungsten, and tin are more restricted. Many of the limitations to specific time intervals are probably imposed by the evolving tectonic history of Earth interacting with the effects of the biomass on the evolution of the earth's s surface chemistry. Photosynthetic generation of free oxygen and "carbon" contributes significantlly to the diversity of redox potentials in both sedimentary and igneous-related processes of ore formation, influencing the selection of metals at the source, during transport, and at the site of ore deposition. PMID:17777763

  7. The enhancement effect of pre-reduction using zero-valent iron on the solidification of chromite ore processing residue by blast furnace slag and calcium hydroxide.

    PubMed

    Li, Jinchunzi; Chen, Zhonglin; Shen, Jimin; Wang, Binyuan; Fan, Leitao

    2015-09-01

    A bench scale study was performed to assess the effectiveness of the solidification of chromite ore processing residue (COPR) by blast furnace slag and calcium hydroxide, and investigate the enhancement effect of pre-reduction using zero-valent iron (ZVI) on the solidification treatment. The degree of Cr immobilization was evaluated using the Toxicity Characteristic Leaching Procedure (TCLP) as well as the solid waste-extraction procedure for leaching toxicity-sulfuric acid & nitric acid method (Chinese standard HJ/T299-2007). Strength tests and semi-dynamic leaching tests were implemented to investigate the potential for reusing the final treatment product as a readily available construction material. The experimental results showed that the performance of pre-reduction/solidification (S/S) was superior to that of solidification alone. After pre-reduction, all of the S/S treated COPR samples met the TCLP limit for total Cr (5mgL(-1)), whereas the samples with a COPR content below 40% met the pollution control limit of bricks and building block products (Chinese standard HJ/T 301-2007) produced with COPR for total Cr (0.3mgL(-1)). At the same time, all of the S/S treated specimens tested were suitable for utilization at certain levels. PMID:25929874

  8. Preparation of pure iron/Ni-Zn ferrite high strength soft magnetic composite by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Wang, Minggang; Zan, Zhao; Deng, Na; Zhao, Zhankui

    2014-06-01

    A dense microcellular structure is fabricated using micron-sized pure iron powder cladded with 10 wt% Zn0.5Ni0.5Fe2O4 nanopowder by filling the pure iron with Ni-Zn-ferrites composite and subjecting the mixture to a temperature of 600 °C. The SEM image shows that the thickness of cell wall is in the range of 1.0-2.0 ?m, and the inner dimension of the alloy is in the range of 15-40 ?m. By coating Ni-Zn-ferrites, the electrical resistivity is increased. The composite exhibits not only good soft magnetic properties but also good mechanical strength.

  9. Sintered soft magnetic materials. Properties and applications

    Microsoft Academic Search

    J. A Bas; J. A Calero; M. J Dougan

    2003-01-01

    A comparison is presented of the characteristics and production requirements of a variety of materials used to produce sintered soft magnetic parts. These include pure iron, phosphorous–iron, silicon–iron, nickel–iron, and cobalt–iron, together with new coated materials based on encapsulated iron powders. In these bonded materials an organic and\\/or inorganic insulator is used to coat the metallic powder particles giving a

  10. Mathematical modeling of the kinetics of carbothermic reduction of iron oxides in ore-coal composite pellets

    SciTech Connect

    Sun, K.; Lu, W.K. [McMaster University, Hamilton, ON (Canada). Dept. for Material Science and Engineering

    2009-02-15

    The kinetics of the carbothermic reduction of iron oxides in a composite pellet made of taconite concentrate and high-volatility coal has been studied by means of mathematical modeling that simultaneously takes into account the transfer rates of both the mass and the heat, and the rates of chemical reactions. The computational results, which have been validated with experimental data in the literature, confirm that the overall rate of the carbothermic reduction, which is strongly endothermic, is limited by heat-transfer steps. From a kinetics viewpoint, the optimum composition of the composite pellet is approximately in accordance with the stoichiometry, when CO is assumed to be the sole oxide of carbon in the gas. To raise the temperature of the pellet from its ambient value to furnace temperature, the heat required is greater than that needed for sustaining all chemical reactions, including the Boudouard reaction. The gaseous product consists mainly of CO and H{sub 2}, except in the very initial stage. The overall observable reaction rate, in terms of the volumetric rate of the generation of gases, peaks at approximately 30 seconds of reaction time.

  11. Chromium Remediation or Release? Effect of Iron(II) Sulfate Addition on Chromium(VI) Leaching from Columns of Chromite Ore Processing Residue 

    E-print Network

    Geelhoed, Jeanine S; Meeussen, Johannes CL; Roe, Martin J; Hillier, Stephen; Thomas, Rhodri P; Farmer, John G; Paterson, Edward

    2003-01-01

    Chromite ore processing residue (COPR), derived from the so-called high lime processing of chromite ore, contains high levels of Cr(III) and Cr(VI) and has a pH between 11 and 12. Ferrous sulfate, which is used for ...

  12. Ore and coal beneficiation method

    SciTech Connect

    Abadi, K.

    1987-10-27

    This patent describes a method for the separation of iron pyrite from a pulverized mineral ore comprising iron pyrites as a first constituent and a second constituent selected from the group consisting of coal and non-ferrous metal ores by air froth flotation of an aqueous pulp of the pulverized mineral ore. The improvement comprises incorporating in the pulp from about 0.02 to about 1 pound per ton of mineral of a composition comprising hydroxyacetic acid, xanthan gum, sodium silicate, and water wherein the acid content of the composition is from about 0.1 to about 69 percent by weight of the composition, the xanthan gum is from about 0.01 to about 10 percent by weight of the composition; and the ratio by weight of sodium silicate to hydroxyacetic acid is in the range of from about 0 to about 0.5.

  13. Microwave sintering of tungsten carbide cobalt hardmetals

    SciTech Connect

    Gerdes, T.; Willert-Porada, M. [Univ. of Dortmund (Germany). Dept. Chemical Engineering; Roediger, K. [WIDIA GmbH, Essen (Germany)

    1996-12-31

    The variety of possible microstructures obtained upon microwave sintering of hardmetals is described with regard to microwave specific heating mechanisms. While the reduction of processing time and temperature is evident, the influence of the microwave sintering process on the microstructure is not fully understood. From microwave sintering experiments at different power levels processes that depends on the local field strength are identified. The mechanical properties of microwave sintered tool bits are compared with commercial WC-Co hardmetals. An incising wear resistance of MW-sintered hardmetals for speed turning of cast iron is found.

  14. Effect of powder reactivity on fabrication and properties of NiAl/Al2O3 composite coated on cast iron using spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Beyhaghi, Maryam; Kiani-Rashid, Ali-Reza; Kashefi, Mehrdad; Khaki, Jalil Vahdati; Jonsson, Stefan

    2015-07-01

    Powder mixtures of Ni, NiO and Al are ball milled for 1 and 10 h. X-ray diffractometry and differential thermal analysis show that while ball milling for 1 h produced mechanically activated powder; 10 h ball milling produced NiAl and Al2O3 phases. Dense NiAl/Al2O3 composite coatings are formed on gray cast iron substrate by spark plasma sintering (SPS) technique. The effect of powder reactivity on microstructure, hardness and scratch hardness of NiAl/Al2O3 coatings after SPS is discussed. Results show that in the coating sample made of mechanically activated powder in situ synthesis of NiAl/Al2O3 composite coating is fulfilled and a thicker well-formed diffusion bond layer at the interface between coating and substrate is observed. The diffusion of elements across the bond layers and phase evolution in the bond layers were investigated. No pores or cracks were observed at the interface between coating layer and substrate in any of samples. Higher Vickers hardness and scratch hardness values in coating made of 10 h ball milled powder than in coating fabricated from 1 h ball milled powder are attributed to better dispersion of Al2O3 reinforcement particles in NiAl matrix and nano-crystalline structure of NiAl matrix. Scratched surface of coatings did not reveal any cracking or spallation at coating-substrate interface indicating their good adherence at test conditions.

  15. Reduction of iron-oxide-carbon composites: part I. Estimation of the rate constants

    SciTech Connect

    Halder, S.; Fruehan, R.J. [Praxair Inc., Tonawanda, NY (United States). Technological Center

    2008-12-15

    A new ironmaking concept using iron-oxide-carbon composite pellets has been proposed, which involves the combination of a rotary hearth furnace (RHF) and an iron bath smelter. This part of the research focuses on studying the two primary chemical kinetic steps. Efforts have been made to experimentally measure the kinetics of the carbon gasification by CO{sub 2} and wustite reduction by CO by isolating them from the influence of heat- and mass-transport steps. A combined reaction model was used to interpret the experimental data and determine the rate constants. Results showed that the reduction is likely to be influenced by the chemical kinetics of both carbon oxidation and wustite reduction at the temperatures of interest. Devolatilized wood-charcoal was observed to be a far more reactive form of carbon in comparison to coal-char. Sintering of the iron-oxide at the high temperatures of interest was found to exert a considerable influence on the reactivity of wustite by virtue of altering the internal pore surface area available for the reaction. Sintering was found to be predominant for highly porous oxides and less of an influence on the denser ores. It was found using an indirect measurement technique that the rate constants for wustite reduction were higher for the porous iron-oxide than dense hematite ore at higher temperatures (> 1423 K). Such an indirect mode of measurement was used to minimize the influence of sintering of the porous oxide at these temperatures.

  16. Iron

    MedlinePLUS

    Iron is a mineral that our bodies need for many functions. For example, iron is part of hemoglobin, a protein which carries ... It helps our muscles store and use oxygen. Iron is also part of many other proteins and ...

  17. Geology of the Eymir iron mine, Edremit, Turkey

    USGS Publications Warehouse

    Jacobson, Herbert Samuel; Turet, Erdogan

    1972-01-01

    The Eymir mine near Edremit on Turkey's Aegean coast (long 27?30'E.,1at 39?36'N.) was investigated as part of the Maden Tetkik ve Arama Enstitutsu (MTA)-U. S. Geological Survey (USGS) mineral exploration and training project, for the purpose of increasing the known mineral reserves. Geologic mapping of the mine area indicates that hematite is restricted to argillized, silicified, and pyritized dacite and possibly andesite. Hematite is present as massive replacements, impregnations, disseminations, and fracture fillings. Most of the upper part of the iron deposit consists of a breccia composed mostly of silicifiled dacite fragments in a hematite matrix. The iron deposit was apparently formed in three steps: 1. Argillation, silicification, and pyritization of the andesitic lava and dacite units as a result of a regional intrusion. 2. Intrusion of the Dere Oren dacite stock, with associated faulting, fracturing, and breccia formation at the surface. 3. Deposition of hematite by oxidation of pyrite, and transfer of iron via fractures and faults by hydrothermal or meteoric fluids. The Eymir iron deposit is a blanketlike deposit on the crest of the Sivritepe-Eymir ridge. It is 1300 meters long, 80 to 450 meters wide, and has an average thickness of 18.6 meters. Drill holes in the deposit show the iron content to range from 32.0 to 57.6 percent, and to average 46.5 percent. Most of the gangue is silica, and an arsenic impurity averaging 0.39 percent is present. Most of the deposit cannot be utilized as iron ore because of low iron content, high silica content, and high arsenic content. Ore-dressing tests have shown that it is feasible to concentrate the low-grade material, producing a concentrate having increased iron content and reduced silica content. Tests have shown also that the arsenic content of the ore can be reduced substantially by sintering. Further tests and economic feasibility studies are necessary to determine whether an economic marketable iron ore can be produced. If such studies indicate the technical and economic feasibility of utilizing all the Eymir iron deposit, detailed additional studies are recommended including: 1. A detailed drilling and sampling program to include 60 drill holes averaging 40 meters in depth and detailed sampling of mine dumps. 2. Pilot-plant testing of concentration and sintering procedures. 3. A detailed pre-investment economic feasibility study.

  18. Biogenic nano-magnetite and nano-zero valent iron treatment of alkaline Cr(VI) leachate and chromite ore processing residue

    PubMed Central

    Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; Pattrick, Richard A.D.; Thomas, Russell A.P.; Kalin, Robert; Lloyd, Jonathan R.

    2015-01-01

    Highly reactive nano-scale biogenic magnetite (BnM), synthesized by the Fe(III)-reducing bacterium Geobacter sulfurreducens, was tested for the potential to remediate alkaline Cr(VI) contaminated waters associated with chromite ore processing residue (COPR). The performance of this biomaterial, targeting aqueous Cr(VI) removal, was compared to a synthetic alternative, nano-scale zero valent iron (nZVI). Samples of highly contaminated alkaline groundwater and COPR solid waste were obtained from a contaminated site in Glasgow, UK. During batch reactivity tests, Cr(VI) removal from groundwater was inhibited by ?25% (BnM) and ?50% (nZVI) when compared to the treatment of less chemically complex model pH 12 Cr(VI) solutions. In both the model Cr(VI) solutions and contaminated groundwater experiments the surface of the nanoparticles became passivated, preventing complete coupling of their available electrons to Cr(VI) reduction. To investigate this process, the surfaces of the reacted samples were analyzed by TEM-EDX, XAS and XPS, confirming Cr(VI) reduction to the less soluble Cr(III) on the nanoparticle surface. In groundwater reacted samples the presence of Ca, Si and S was also noted on the surface of the nanoparticles, and is likely responsible for earlier onset of passivation. Treatment of the solid COPR material in contact with water, by addition of increasing weight % of the nanoparticles, resulted in a decrease in aqueous Cr(VI) concentrations to below detection limits, via the addition of ?5% w/w BnM or ?1% w/w nZVI. XANES analysis of the Cr K edge, showed that the % Cr(VI) in the COPR dropped from 26% to a minimum of 4–7% by the addition of 5% w/w BnM or 2% w/w nZVI, with higher additions unable to reduce the remaining Cr(VI). The treated materials exhibited minimal re-mobilization of soluble Cr(VI) by re-equilibration with atmospheric oxygen, with the bulk of the Cr remaining in the solid fraction. Both nanoparticles exhibited a considerable capacity for the remediation of COPR related Cr(VI) contamination, with the synthetic nZVI demonstrating greater reactivity than the BnM. However, the biosynthesized BnM was also capable of significant Cr(VI) reduction and demonstrated a greater efficiency for the coupling of its electrons towards Cr(VI) reduction than the nZVI. PMID:26109747

  19. Ore Melting and Reduction in Silicomanganese Production

    NASA Astrophysics Data System (ADS)

    Ringdalen, Eli; Gaal, Sean; Tangstad, Merete; Ostrovski, Oleg

    2010-12-01

    The charge for silicomangansese production consists of manganese ore (often mixed with ferromanganese slag) dolomite or calcite, quartz, and in some cases, other additions. These materials have different melting properties, which have a strong effect on reduction and smelting reactions in the production of a silicomanganese alloy. This article discusses properties of Assman, Gabonese, and Companhia Vale do Rio Doce (CVRD) ores, CVRD sinter and high-carbon ferromanganese (HC FeMn) slag, and their change during silicomanganese production. The melting and reduction temperatures of these manganese sources were measured in a carbon monoxide atmosphere, using the sessile drop method and a differential thermal analysis/thermogravimetric analysis. Equilibrium phases were analyzed using FACTSage (CRCT, Montreal, Canada and GTT, Aachen, Germany) software. Experimental investigations and an analysis of equilibrium phases revealed significant differences in the melting behavior and reduction of different manganese sources. The difference in smelting of CVRD ore and CVRD sinter was attributed to a faster reduction of sinter by the graphite substrate and carbon monoxide. The calculation of equilibrium phases in the reduction process of manganese ores using FACTSage correctly reflects the trends in the production of manganese alloys. The temperature at which the manganese oxide concentration in the slag was reduced below 10 wt pct can be assigned to the top of the coke bed in the silicomanganese furnace. This temperature was in the range 1823 K to 1883 K (1550 °C to 1610 °C).

  20. Phase II Calderon Process to Produce Direct Reduced Iron Research and Development Project

    SciTech Connect

    Albert Calderon

    2007-03-31

    This project was initially targeted to the making of coke for blast furnaces by using proprietary technology of Calderon in a phased approach, and Phase 1 was successfully completed. The project was then re-directed to the making of iron units. In 2000, U.S. Steel teamed up with Calderon for a joint effort to produce directly reduced iron with the potential of converting it into molten iron or steel consistent with the Roadmap recommendations of 1998 prepared by the Steel Industry in cooperation with the Department of Energy by using iron ore concentrate and coal as raw materials, both materials being appreciably lower in cost than using iron pellets, briquettes, sinter and coke.

  1. By Thomas S. Jones Manganese (Mn) is essential to iron and silicomanganese increased about 7%. consisted of, in tons, natural battery-grade ore,

    E-print Network

    Torgersen, Christian

    about 7%. consisted of, in tons, natural battery-grade ore, steel production by virtue of its sulfur aluminum alloys and is used in oxide form in dry cell batteries. The overall level and nature of manganese consumption in batteries was denoted by the expansion on schedule of domestic capacity for production

  2. Iron

    MedlinePLUS

    ... disease and restless leg syndrome. Taking iron with levothyroxine can reduce this medication’s effectiveness. Levothyroxine (Levothroid®, Levoxyl®, Synthroid®, Tirosint®, and Unithroid®) is used ...

  3. Effects of Alloy Composition on Microstructure and Mechanical Properties of Iron-Based Materials Fabricated by Ball Milling and Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Ye, Yongquan; Li, Xiaoqiang; Hu, Ke; Qu, Shengguan; Li, Yuanyuan

    2015-01-01

    Three PM steels, Fe-0.8C, Fe-2Cu-1.5Ni-0.5Mo-0.8C, and Fe-2Cu-2Ni-1Mo-1C, were fabricated by mechanical milling and spark plasma sintering. Dense sintered samples with fine and homogeneous microstructure were obtained. According to the results of X-ray diffraction, differential scanning calorimetry, and scanning electron microscopy, it is suggested that the temperature of the sample can be ~50 K (50 °C) greater than that recorded. The microstructures of the as-sintered samples are divided into two groups. One consists of both ferritic and martensitic structures, and the others are of a ferritic structure. A considerable amount of martensite exists only in those high alloy Fe-2Cu-2Ni-1Mo-1C samples. The hardness of the sintered samples mainly depends on microstructure and composition. It shows that the hardness enhances with the volume fraction of martensite. However, a lower compressive strength is observed in the samples with higher volume fraction of martensite. The analysis of the deformation behavior demonstrates that the yield strength and ultimate strength are solely correlated to the properties of ferritic structure. Discontinuously yielding phenomenon, initial work hardening exponent, and decreasing rate of strain hardening exponent with strain are considered to be sensitive to the morphology of carbides formed in the ferritic structure.

  4. Iron and Steel Phosphate Rock

    E-print Network

    Torgersen, Christian

    Phosphate Rock Platinum Potash Pumice Quartz Crystal Rare Earths Rhenium Rubidium Salt Sand and Gravel Cadmium Iodine Pumice Thorium Cement Iron Ore Quartz Crystal Tin Cesium Iron and Steel Rare Earths

  5. Sources of ores of the ferroalloy metals

    USGS Publications Warehouse

    Burchard, E.F.

    1933-01-01

    Since all steel is made with the addition of alloying elements, the record of the metallic raw materials contributory to the steel industry would be far from complete without reference to the ferroalloy metals. This paper, therefore, supplements two preceding arvicles on the sources of our iron ores. The photographs, with the exception of those relating to molybdenum and vanadium, are by the author.

  6. Research on the Technology of Integrated Recovery and Collaborative Power Generation for Sintering Dual Waste Heat Source

    Microsoft Academic Search

    Bin Zhao; Yuzhu Zhang; Changqing Hu; Shibin Wan

    2010-01-01

    With the establishment of national iron and steel project and the urgent demand of energy-saving and emission-reducing, Integrated recovering the sensible heat of sintering machine's flue gas and sintering mine effectively to generate power has become problems that are starve for figuring out. Regarding the work process of sintering in iron and steel industry as the target of research, this

  7. Pilot plant production of ferronickel from nickel oxide ores and dusts in a DC arc furnace

    Microsoft Academic Search

    I. J Kotzé

    2002-01-01

    Laterites and other oxidized nickel ores constitute a very important part of world-wide nickel reserves. The development of nickel oxide ore smelting has drawn heavily on iron and steel metallurgy. In ferronickel production, the nickel oxide and part of the iron oxide are reduced to metal in an electric furnace to form immiscible layers of slag and metal. The crude

  8. In situ X-ray diffraction of pyrolite to 40 GPa using Kawai-type apparatus with sintered diamond anvils: possibility for the existence of iron-rich metallic particles in the lower mantle

    SciTech Connect

    Kubo, A.; Ito, E.; Katsura, T.; Fujino, K.; Funakoshi, K. (Hokkaido); (JASRI); (UC); (Okayama)

    2008-11-12

    We investigated phase relations in pyrolite at -33--40 GPa and -1800--2150 K by in situ X-ray diffraction using Kawai-type apparatus with sintered diamond anvils. The results demonstrated that MgSiO{sub 3}-rich orthorhombic perovskite (mpv), CaSiO{sub 3}-rich cubic perovskite (cpv) and (Mg,Fe)O ferropericlase (fp) are the stable phases in pyrolite bulk composition at the conditions corresponding to the lower mantle. However, chemical analyses of a run product recovered from -34 GPa by an analytical transmission electron microscope showed the coexistence of metallic iron particles with mpv, fp, and SiO{sub 2}-rich amorphous phase. Also, Fe/Mg partitioning coefficient between mpv and fp was found to be 0.66(31), which is consistent with previous results for pyrolite bulk composition at 26--30 GPa and -1900 K. These results indicate that iron-rich metallic particles can exist in the lower mantle as a stable phase to the depth of at least -900 km.

  9. Influence of intermediate-heat treatment on the structure and magnetic properties of iron-rich Sm(CoFeCuZr)Z sintered magnets

    NASA Astrophysics Data System (ADS)

    Horiuchi, Yosuke; Hagiwara, Masaya; Endo, Masaki; Sanada, Naoyuki; Sakurada, Shinya

    2015-05-01

    In this study, we investigated intermediate-heat treatment (IHT) at temperatures between those of sintering and solution treatment, and evaluated the effects on the macrostructure, microstructure, and magnetic properties of Sm(Cobal.Fe0.35Cu0.06Zr0.018)7.8. We found that squareness was clearly improved by adopting the IHT, which promotes grain growth. These results indicate that reducing the fraction of grain boundaries by increasing the grain size affects the behavior of domain-wall motion. Magnetic properties of Mr 1.22 T, HcJ 1580 kA/m, and (BH)max 282 kJ/m3 (>35 MGOe) were obtained for Sm(Cobal.Fe0.35Cu0.06Zr0.018)7.8 subjected to IHT at 1453 K.

  10. Fungal bio-leaching of low grade laterite ores

    Microsoft Academic Search

    M Valix; F Usai; R Malik

    2001-01-01

    In this study, the mineral leaching ability of heterotrophic fungi, through secretion of organic acids, of various laterite ores was studied. Ores subjected to the leaching process included saprolite, weathered saprolite, limonite and nontronite. Strains of Aspergillus and Penicillium were found to be the most efficient organisms. Nickel extraction of up to 36wt%, cobalt of 54wt% and iron of 0.76wt%

  11. Ores and Climate Change - Primary Shareholders

    NASA Astrophysics Data System (ADS)

    Stein, Holly J.; Hannah, Judith L.

    2015-04-01

    Many in the economic geology community concern themselves with details of ore formation at the deposit scale, whether tallying fluid inclusion data to get at changes in ore-forming fluids or defining structures that aid and abet mineralization. These compilations are generally aimed at interpretation of events at the site of ore formation, with the goal being assignment of the deposit to a sanctioned ore deposit model. While providing useful data, this approach is incomplete and does not, by itself, serve present-day requirements for true interdisciplinary science. The ore-forming environment is one of chaos and disequilibrium at nearly all scales (Stein, 2014). Chaos and complexity are documented by variably altered rocks, veins or disseminated mineralization with multi-generational fluid histories, erratic and unusual textures in host rocks, and the bitumen or other hydrocarbon products entwined within many ore deposits. This should give pause to our drive for more data as a means to find "the answer". The answer lies in the kind of data collected and more importantly, in the way we interpret those data. Rather than constructing an ever-increasing catalog of descriptive mutations on sanctioned ore deposit models (e.g., IOGC or Iron-Oxide Copper Gold deposits), the way forward is to link source and transport of metals, sulfur, and organic material with regional and ultimately whole Earth chemical evolution. Important experimental work provides chemical constraints in controlled and behaved environments. To these data, we add imagination and interpretation, always tying back to field observations. In this paper, several key points are made by way of ore deposit examples: (1) many IOCG deposits are outcomes of profound changes in the chemistry of the Earth's surface, in the interplay of the atmosphere, hydrosphere, biosphere, and lithosphere; (2) the redox history of Fe in deep earth may be ultimately expressed in the ore-forming sequence; and (3) the formation of many giant Cu-Mo-Au ore deposits may be arrested when the surface is catastrophically breached, as multiple km-scale breccia pipes empty their volatile and metal contents into the atmosphere. The new equation for studying ore geology should be one that reconstructs ore formation from beginning to end, that is, from source, release, and transport, to breach. Of course, detailed measurements and mapping of ore bodies remains essential, but a full understanding of metal migration and budgets can only be achieved if we model what might have been left behind in deeper Earth, and what may have been lost to the atmosphere. To do this, we need to understand much more than the geology at our ore deposit of interest. Stein, H.J. (2014) Dating and Tracing the History of Ore Formation. Treatise on Geochemistry 13: 87-118. Elsevier. Support for time to think - CHRONOS, funded by a consortium of Norwegian petroleum companies.

  12. P-V-T equation of state for ?-iron up to 80 GPa and 1900 K using the Kawai-type high pressure apparatus equipped with sintered diamond anvils

    NASA Astrophysics Data System (ADS)

    Yamazaki, D.; Ito, E.; Yoshino, T.; Yoneda, A.; Guo, X.; Shimojuku, A.; Tsujino, N.; Kunimoto, T.; Higo, Y.; Funakoshi, K.

    2012-12-01

    The earth's core is considered to be predominantly composed of iron alloy [e.g., Birch, 1952]. Although, it was clarified that the inner core is solid from the seismological observation in early 20th century, the crystal structure of iron in the inner core condition has long been open question. However, recent progress in high pressure experiment using the diamond anvil cell (DAC) have revealed that the iron and its Ni-alloy assumes the hexagonal closed packed structure (hcp, ?-iron) under the inner core conditions [Tateno et al., 2010, 2012]. Therefore, the P-V-T equation of state of ?-iron is crucial information to understand the nature of the inner core. Despite many studies on the direct volume measurement by X-ray diffraction study of ?-iron at high pressure [Mao and Bell, 1979; Jephcoat et al., 1986; Huang et al., 1987; Mao et al., 1990; Funamori et al., 1996; Dubrovinsky et al., 1998, 2000; Uchida et al., 2001; Dewaele et al., 2006; Boehler et al., 2008; Ono et al., 2010], P-V-T relationship of ?-iron has not been well determined yet. This is mainly due to the limitations in experimental P-T ranges and lack of precision of X-ray diffraction data. In this study, we used a KMA equipped with sintered diamond (SD) anvils which enable us to generate pressure to ~100 GPa at present [Yamazaki, 2011]. The KMA allows stable and uniform sample temperature and high quality data because of the large sample volume and wide d-value range (~0.85~3 Å) with a polychromatic X-ray beam for diffraction. We precisely measured volumes of ?-iron up to 80 GPa and 1900 K, which enables us to derive more reliable thermoelastic parameters by fitting to suitable equation of state. The P-V-T data set of ?-iron was fitted to a single EOS model based on the Mie-Grüneisen equation and we obtained unit cell volume V0=22.15(5) Å^3, KT0=202(7) GPa, K0'=4.5(2), ?0=3.2(2), ?0=1173(62) K and q=0.8(3) when third-order Birch-Murnaghan equation was used, whereas we obtained V0=22.17(6) Å^3, KT0=196(8) GPa, K0'=4.8(2), ?0=3.2(2), ?0=1168(61) K and q=0.8(3) when Vinet equation was used. The thermal expansion coefficient at ambient pressure was determined to be ?0(K^-1)=3.7(2)*10^-5+7.2(6)*10^-8*(T-300) and Anderson-Grüneisen parameter ?T=6.2(3). Density of the inner core at around the inner and outer core boundary region (~330 GPa) is estimated to be 12.76 g/cm^3 from seismic observation (e.g., PREM [Dziewonski and Anderson, 1981]). In the comparison with the density of iron, thermal expansion derived from the volume data of iron at high temperature is a key factor. In this study, we successfully obtained volume data at high temperature, and we calculated the density of iron at 330 GPa and 6000K to be 13.12 and 13.18 g/cm^3 using a third-order Birch-Murnaghan equation and Vinet equation, respectively, corresponding to the density deficits of 2.7 and 3.1 %, respectively. These estimations are similar to those by Dubrovinsky et al [2000], Uchida et al. [2001] and Dewaele et al. [2006]. Because Ni-alloying into ?-iron is expected to increase its density, by approximately 0.4% [Mao et al., 1990], it is highly likely that the inner core contains certain amounts of light elements such as Si, C, O, S, and H, as same situation as the outer core but definitely smaller amount.

  13. Iron and Steel Phosphate Rock

    E-print Network

    Torgersen, Christian

    Phosphate Rock Platinum Potash Pumice Quartz Crystal Rare Earths Rhenium Rubidium Salt Sand and Gravel Platinum Tellurium Bromine Indium Potash Thallium Cadmium Iodine Pumice Thorium Cement Iron Ore Quartz

  14. Sintering Theory and Practice

    Microsoft Academic Search

    Randall M. German

    1996-01-01

    Although sintering is an essential process in the manufacture of ceramics and certain metals, as well as several other industrial operations, until now, no single book has treated both the background theory and the practical application of this complex and often delicate procedure. In Sintering Theory and Practice, leading researcher and materials engineer Randall M. German presents a comprehensive treatment

  15. LIQUID PHASE SINTERED METAL MATRIX COMPOSITE MATERIALS

    Microsoft Academic Search

    S. J. Yankee; G. M. Janowski; B. J. Pletka

    1990-01-01

    Iron-base and aluminum-base composite materials reinforced with various ceramic particulates have been fabricated via powder metallurgy and liquid phase sintering. The advantage of this manufacturing route is that conventional powder metallurgy processing equipment can be used to fabricate metal matrix\\/ceramic composites. Furthermore, this approach makes it possible to manufacture these composites to near-net-shape. A number of matrix\\/ceramic combinations have been

  16. 14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...

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

    14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE 'GEORGE M. CAR.' VIEW LOOKING EAST. (Also see OH-18-38, OH-18-39, and OH-18-40.) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  17. 38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...

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

    38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE GEORGE M. CARL.' VIEW LOOKING EAST. (Also see OH-18-14, OH-18-39, and OH-18-40) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  18. Sintering Reaction of Pseudoleucite Syenite: Thermodynamic Analysis and Process Evaluation

    NASA Astrophysics Data System (ADS)

    TAN, Danjun; MA, Hongwen; LI, Ge; LIU, Hao; ZOU, Dan

    On the basis of comprehensive analysis of the modal composition of a pseudoleucite syenite ore sample, collected from the Zijin Hill of Lin County, Shanxi Province, thermodynamic analysis of the pseudoleucite syenite sintering process with sodium carbonate as the additive was carried out. It indicated that when the pseudoleucite syenite was sintered at 760-880°C for 1.0-1.5 h, with sodium carbonate as the additive. The decomposition rate of minerals in the pseudoleucite syenite could reach 97.1%. The thermodynamic calculation shows that it needs to consume Na 2CO 3, i.e., 0.65 t treating per ton pseudoleucite syenite ore and approximately 95% of Na 2CO 3 could be recycled. This process consumes heat energy (2.29-2.48)×10 -6 kJ, corresponding to standard coal 190.97-206.82 kg as the thermal efficiency was 40% and CO 2 emission was 0.77-0.81 t. Compared with the Russian limestone-sintering technique, the natural mineral resources and energy consumptions and greenhouse gas emissions of the soda-sintering technique were reduced by 65%, 63%, and 65%, respectively. It is, therefore, feasible that the procedure suggested in this article could be industrialized providing both economic benefit and environmental conservation.

  19. Sintering titanium powders

    SciTech Connect

    Gerdemann, Stephen J.; Alman, David E.

    2005-09-01

    Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press-and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350°C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics, with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

  20. Computer finds ore

    Microsoft Academic Search

    Peter M. Bell

    1982-01-01

    Artificial intelligence techniques are being used for the first time to evaluate geophysical, geochemical, and geologic data and theory in order to locate ore deposits. After several years of development, an intelligent computer code has been formulated and applied to the Mount Tolman area in Washington state. In a project funded by the United States Geological Survey and the National

  1. A Novel Sintering Gas Desulphurization Technology Applied in the Sintering Plants in China

    NASA Astrophysics Data System (ADS)

    Ting, Jin; Tingyu, Zhu; Pengfei, Jing; Meng, Ye

    2010-05-01

    The emission of sulfur dioxide (SO2) produced by the sinter machine takes up more than 50% of the total SO2 emission of the iron and steel industry in China. So it is necessary to take effective measures to strengthen the control of sintering gas desulphurization. A novel sintering gas desulphurization technology, the inner and outer circulating fluidized bed (IOCFB) which is suitable for retrofitting the existing metallurgical industry plants in China will be introduced in this paper. The novel composite internals which can improve the removal efficiency of SO2 is also described. Current research and development needs for IOCFB are to further increase desulphurization efficiency and improve the reliability of plant components. To solve these problems, a pilot plant emulating IOCFB desulfurization processes had been built.

  2. Ore-fluid evolution at the Getchell Carlin-type gold deposit, Nevada, USA

    USGS Publications Warehouse

    Cline, J.S.; Hofstra, A.A.

    2000-01-01

    Minerals and fluid-inclusion populations were examined using petrography, microthermometry, quadrupole mass-spectrometer gas analyses and stable-isotope studies to characterize fluids responsible for gold mineralization at the Getchell Carlin-type gold deposit. The gold-ore assemblage at Getchell is superimposed on quartz-pyrite vein mineralization associated with a Late-Cretaceous granodiorite stock that intruded Lower-Paleozoic sedimentary rocks. The ore assemblage, of mid-Tertiary age, consists of disseminated arsenian pyrite that contains submicrometer gold, jasperoid quartz, and later fluorite and orpiment that fill fractures and vugs. Late ore-stage realgar and calcite enclose ore-stage minerals. Pre-ore quartz trapped fluids with a wide range of salinities (1 to 21 wt.% NaCl equivalent), gas compositions (H2O, CO2, and CH4), and temperatures (120 to >360??C). Oxygen- and hydrogen-isotope ratios indicate that pre-ore fluids likely had a magmatic source, and were associated with intrusion of the granodiorite stock and related dikes. Ore-stage jasperoid contains moderate salinity, aqueous fluid inclusions trapped at 180 to 220??C. Ore fluids contain minor CO2 and trace H2S that allowed the fluid to react with limestone host rocks and transport gold, respectively. Aqueous inclusions in fluorite indicate that fluid temperatures declined to ~175??C by the end of ore-stage mineralization. As the hydrothermal system collapsed, fluid temperatures declined to 155 to 115??C and realgar and calcite precipitated. Inclusion fluids in ore-stage minerals have high ??D(H2O) and ??18O(H2O) values that indicate that the fluid had a deep source, and had a metamorphic or magmatic origin, or both. Late ore-stage fluids extend to lower ??D(H2O) values, and have a wider range of ??18O(H2O) values suggesting dilution by variably exchanged meteoric waters. Results show that deeply sourced ore fluids rose along the Getchell fault system, where they dissolved carbonate wall rocks and deposited gold-enriched pyrite and jasperoid quartz. Gold and pyrite precipitated together as H2S in the ore fluids reacted with iron in the host rocks. As ore fluids mixed with local aquifer fluids, ore fluids became cooler and more dilute. Cooling caused precipitation of ore-stage fluorite and orpiment, and late ore-stage realgar. Phase separation and/or neutralization of the ore fluid during the waning stages of the hydrothermal ore system led to deposition of late ore-stage calcite.

  3. 77 FR 44204 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Control of Iron and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ...Implementation Plans; Maryland; Control of Iron and Steel Production Installations; Sintering...Maryland SIP's regulation for the Control of Iron and Steel Production Installations as they...section of the regulation for the Control of Iron and Steel Production Installations...

  4. Accuracy in Powder Diffraction IV NIST, Gaithersburg MD, USA

    E-print Network

    Magee, Joseph W.

    , magnetite Fe3O4, goethite FeOOH) ­ Al content (increases viscosity of the slag in blast furnace) ­ Plus Austenite) Intermediate products Sinter, blast furnace Pellets, DRI Steel plant #12;Mining of iron ore applications in the iron making process: ­ Iron ore ­ Iron ore sinter ­ DRI (sponge iron) ­ Steel ­ Slag #12

  5. Effect of the powder characteristics of Sisub3Nsub4 on the microstructure of sintered bodies

    NASA Technical Reports Server (NTRS)

    Woetting, G.; Hausner, H.

    1981-01-01

    Silicon nitride powders sintered with the addition of 2 wt% Mg0 to 95% theoretical density after attrition milling and subsequent purification were evaluated. Preparation of the powders is described. The powder characteristics (specific surfaces, iron concentration, and oxygen content), and density, weight loss, and phase state of the sinter bodies as a function of powder preparation are presented.

  6. Sintered wire annode

    DOEpatents

    Falce, Louis R. (Surprise, AZ); Ives, R. Lawrence (Saratoga, CA)

    2007-12-25

    A plurality of high atomic number wires are sintered together to form a porous rod that is parted into porous disks which will be used as x-ray targets. A thermally conductive material is introduced into the pores of the rod, and when a stream of electrons impinges on the sintered wire target and generates x-rays, the heat generated by the impinging x-rays is removed by the thermally conductive material interspersed in the pores of the wires.

  7. Single-Step Ironmaking from Ore to Improve Energy Efficiency

    SciTech Connect

    S.K. Kawatra; B. Anamerie; T.C. Eisele

    2005-10-01

    The pig iron nugget process was developed as an alternative to the traditional blast furnace process by Kobe Steel. The process aimed to produce pig iron nuggets, which have similar chemical and physical properties to blast furnace pig iron, in a single step. The pig iron nugget process utilizes coal instead of coke and self reducing and fluxing dried green balls instead of pellets and sinters. In this process the environmental emissions caused by coke and sinter production, and energy lost between pellet induration (heat hardening) and transportation to the blast furnace can be eliminated. The objectives of this research were to (1) produce pig iron nuggets in the laboratory, (2) characterize the pig iron nugget produced and compare them with blast furnace pig iron, (3) investigate the furnace temperature and residence time effects on the pig iron nugget production, and (4) optimize the operational furnace temperatures and residence times. The experiments involved heat treatment of self reducing and fluxing dried green balls at various furnace temperatures and residence times. Three chemically and physically different products were produced after the compete reduction of iron oxides to iron depending on the operational furnace temperatures and/or residence times. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and pig iron nuggets. The increase in the carbon content of the system as a function of furnace temperature and/or residence time dictated the formation of these products. The direct reduced iron, transition direct reduced iron, and pig iron nuggets produced were analyzed for their chemical composition, degree of metallization, apparent density, microstructure and microhardness. In addition, the change in the carbon content of the system with the changing furnace temperature and/or residence time was detected by optical microscopy and Microhardness measurements. The sufficient carbon dissolution required for the production of pig iron nuggets was determined. It was determined that pig iron nuggets produced had a high apparent density (6.7-7.2 gr/cm3), highly metallized, slag free structure, high iron content (95-97%), high microhardness values (> 325 HVN) and microstructure similar to white cast iron. These properties made them a competitive alternative to blast furnace pig iron.

  8. Management of solid wastes in the iron and steel industry

    SciTech Connect

    El-Gohary, F.; El-khouly, M.S.

    1983-03-01

    Wastes from a local iron and steel factory operations are agglomeration of iron ore and sintering, pig iron manufacture, steel making, rolling mill operations, and pickling. Liquid slag, produced in the blast furnace, is granulated in water and used as a concrete additive. Other wastes are directed separately to sedimentation tanks. The settleable solids are reused, and the treated effluents are pumped to a cooling tower for recycling. As a result of the new manufacturing expansion, existing waste treatment facilities are not adequate, and it was found necessary to provide additional treatment techniques. Departmental, as well as composite wastes were treated using plain sedimentation, centrifugal sedimentation, or chemical coagulation, or a combination of these methods. The results obtained showed that the use of the hydrocyclone for solid-liquid separation is much more efficient than plain sedimentation. When this process was followed by coagulation, very promising results were obtained. The use of pickling liquor as a coagulant gave comparable results with alum and ferric chloride.

  9. ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE ...

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

    ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE MINES ABOVE AT THE RIDGELINE AND TO THE RIGHT WAS CONVEYED TO THIS AREA AND DUMPED INTO THE SHAFT AT CENTER. THIS SHAFT OPENS INTO THE ADIT AT BOTTOM CENTER. THERE IS ANOTHER SHAFT OPENING INTO THE ADIT JUST ABOVE THE ADIT BEHIND THE STONE WALL. THE ORE WAS LOADED INTO TRAM CARS INSIDE THE ADIT AND CONVEYED ON TRACKS TO THE TRESTLE LEADING TO THE PRIMARY ORE BIN AT THE TRAM TERMINAL. TRACKS CAN BE SEEN LEADING FROM THE ADIT AND TO THE LEFT. THE ORE WAS THEN DUMPED INTO A CHUTE AT THE END OF THE TRESTLE CARRYING IT INTO THE ORE BIN AT THE TRAM TERMINAL(SEE CHUTE ON CA-291-30). - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  10. Sintering Theory and Practice

    NASA Astrophysics Data System (ADS)

    German, Randall M.

    1996-01-01

    Although sintering is an essential process in the manufacture of ceramics and certain metals, as well as several other industrial operations, until now, no single book has treated both the background theory and the practical application of this complex and often delicate procedure. In Sintering Theory and Practice, leading researcher and materials engineer Randall M. German presents a comprehensive treatment of this subject that will be of great use to manufacturers and scientists alike. This practical guide to sintering considers the fact that while the bonding process improves strength and other engineering properties of the compacted material, inappropriate methods of control may lead to cracking, distortion, and other defects. It provides a working knowledge of sintering, and shows how to avoid problems while accounting for variables such as particle size, maximum temperature, time at that temperature, and other problems that may cause changes in processing. The book describes the fundamental atomic events that govern the transformation from particles to solid, covers all forms of the sintering process, and provides a summary of many actual production cycles. Building from the ground up, it begins with definitions and progresses to measurement techniques, easing the transition, especially for students, into advanced topics such as single-phase solid-state sintering, microstructure changes, the complications of mixed particles, and pressure-assisted sintering. German draws on some six thousand references to provide a coherent and lucid treatment of the subject, making scientific principles and practical applications accessible to both students and professionals. In the process, he also points out and avoids the pitfalls found in various competing theories, concepts, and mathematical disputes within the field. A unique opportunity to discover what sintering is all about--both in theory and in practice What is sintering? We see the end product of this thermal process all around us--in manufactured objects from metals, ceramics, polymers, and many compounds. From a vast professional literature, Sintering Theory and Practice emerges as the only comprehensive, systematic, and self-contained volume on the subject. Covering all aspects of sintering as a processing topic, including materials, processes, theories, and the overall state of the art, the book Offers numerous examples, illustrations, and tables that detail actual processing cycles, and that stress existing knowledge in the field Uses the specifics of various consolidation cycles to illustrate the basics Leads the reader from the fundamentals to advanced topics, without getting bogged down in various mathematical disputes over treatments and measurements Supports the discussion with critically selected references from thousands of sources Examines the sintering behavior of a wide variety of engineered materials--metals, alloys, oxide ceramics, composites, carbides, intermetallics, glasses, and polymers Guides the reader through the sintering processes for several important industrial materials and demonstrates how to control these processes effectively and improve present techniques Provides a helpful reference for specific information on materials, processing problems, and concepts For practitioners and researchers in ceramics, powder metallurgy, and other areas, and for students and faculty in materials science and engineering, this book provides the know-how and understanding crucial to many industrial operations, offers many ideas for further research, and suggests future applications of this important technology. This book offers an unprecedented opportunity to explore sintering in both practical and theoretical terms, whether at the lab or in real-world applications, and to acquire a broad, yet thorough, understanding of this important technology.

  11. Computer finds ore

    NASA Astrophysics Data System (ADS)

    Bell, Peter M.

    Artificial intelligence techniques are being used for the first time to evaluate geophysical, geochemical, and geologic data and theory in order to locate ore deposits. After several years of development, an intelligent computer code has been formulated and applied to the Mount Tolman area in Washington state. In a project funded by the United States Geological Survey and the National Science Foundation a set of computer programs, under the general title Prospector, was used successfully to locate a previously unknown ore-grade porphyry molybdenum deposit in the vicinity of Mount Tolman (Science, Sept. 3, 1982).The general area of the deposit had been known to contain exposures of porphyry mineralization. Between 1964 and 1978, exploration surveys had been run by the Bear Creek Mining Company, and later exploration was done in the area by the Amax Corporation. Some of the geophysical data and geochemical and other prospecting surveys were incorporated into the programs, and mine exploration specialists contributed to a set of rules for Prospector. The rules were encoded as ‘inference networks’ to form the ‘expert system’ on which the artificial intelligence codes were based. The molybdenum ore deposit discovered by the test is large, located subsurface, and has an areal extent of more than 18 km2.

  12. Reductive leaching of ilmenite ore in hydrochloric acid for preparation of synthetic rutile

    Microsoft Academic Search

    M. H. H. Mahmoud; A. A. I. Afifi; I. A. Ibrahim

    2004-01-01

    The reactivity of ilmenite ore during leaching with hydrochloric acid can be greatly enhanced by reduction in solution using metallic iron. Addition of a particular amount of iron powder after a certain time of reaction will reduce all the dissolved Fe3+ to Fe2+ and reduce a portion of the dissolved Ti4+ to Ti3+. As the leaching continues, any further dissolved

  13. Sintering of Lunar and Simulant Glass

    NASA Technical Reports Server (NTRS)

    Cooper, Bonnie L.

    2007-01-01

    Most oxygen-extraction techniques are temperature-dependent, with higher temperatures resulting in higher oxygen yield. An example is hydrogen reduction, in which the optimum process temperature is 1050 C. However, glass-rich lunar soil begins to show the effects of sintering at temperatures of 900 C or lower. Sintering welds particles together due to viscous relaxation of the glass in the sample. One approach to avoid problems related to sintering, such as difficulty in removing waste material from the reactor, is to keep the soil in motion. One of several methods being studied to accomplish this is fluidized-bed processing techniques, in which the grains are kept in motion by the action of flowing reductant gas. The spent material can be removed from the chamber while still fluidized, or the fluidizing motion can continue until the material has cooled below approx. 500 C. Until end-to-end prototypes are built that can remove the heated soil, the most practical option is to keep the bed fluidized while cooling the waste material. As ISRU technology advances, another option will become valuable, which is to intentionally sinter the material to a great enough extent that it becomes a brick. The free iron in lunar soil is magnetic, and ferromagnetic bricks can be manipulated by robotic systems using electromagnetic end effectors. Finally, if an electromagnetic field is applied to the soil while the brick is being formed, the brick itself will become a magnet. This property can be used to create self-aligning bricks or other building materials that do not require fasteners. Although sintering creates a challenge for early lunar surface systems, knowledge gained during prototype development will be valuable for the advanced lunar outpost.

  14. Sintering of Synroc D

    NASA Astrophysics Data System (ADS)

    Robinson, Gaythia

    1982-06-01

    Sintering was investigated as a method for the mineralization and densification of high-level nuclear defense waste powder. Studies were conducted on Synroc D composite powder LS04. Optimal densification was found to be highly dependent on the characteristics of the starting material. Powder subjected to milling, which was believed to reduce the level of agglomeration and possibly particle size, was found to densify better than powder not subjected to this milling. Densities of greater than 95% of theoretical could be achieved for samples sintered at 1150 to 1200 C. Mineralogy was found to be as expected for Synroc D.

  15. SinterHab

    NASA Astrophysics Data System (ADS)

    Rousek, Tomáš; Eriksson, Katarina; Doule, Ond?ej

    2012-05-01

    This project describes a design study for a core module on a Lunar South Pole outpost, constructed by 3D printing technology with the use of in-situ resources and equipped with a bio-regenerative life support system. The module would be a hybrid of deployable (CLASS II) and in-situ built (CLASS III) structures. It would combine deployable membrane structures and pre-integrated rigid elements with a sintered regolith shell for enhanced radiation and micrometeorite shielding. The closed loop ecological system would support a sustainable presence on the Moon with particular focus on research activities. The core module accommodates from four to eight people, and provides laboratories as a test bed for development of new lunar technologies directly in the environment where they will be used. SinterHab also includes an experimental garden for development of new bio-regenerative life support system elements. The project explores these various concepts from an architectural point-of-view particularly, as they constitute the building, construction and interior elements. The construction method for SinterHab is based on 3D printing by sintering of the lunar regolith. Sinterator robotics 3D printing technology proposed by NASA JPL enables construction of future generations of large lunar settlements with little imported material and the use of solar energy. The regolith is processed, placed and sintered by the Sinterator robotics system which combines the NASA ATHLETE and the Chariot remotely controlled rovers. Microwave sintering creates a rigid structure in the form of walls, vaults and other architectural elements. The interior is coated with a layer of inflatable membranes inspired by the TransHab project. The life-support system is mainly bio-regenerative and several parts of the system are intrinsically multifunctional and serve more than one purpose. The plants for food production are also an efficient part of atmosphere revitalization and water treatment. Moreover, the plants will be used as a "winter garden" for psychological and recreational purposes. The water in the revitalization system has a multifunctional use, as radiation shielding in the safe-haven habitat core. The garden module creates an artificial outdoor environment mitigating the notion of confinement on the lunar surface. Fiber optics systems and plasma lamps are used for transmission of natural and artificial light into the interior.

  16. Effect of heating mode on sinterability of Fe-Ni steels.

    PubMed

    Annamalai, A Raja; Kumar, Rajiv; Upadhyaya, Anish; Agrawal, Dinesh

    2011-01-01

    The present study examines the effect of heating mode on the densification, microstructure, and mechanical properties of iron-nickel steel with graphite and phosphorus addition. The compacts were sintered in conventional (radiatively-heated) and microwave (2.45 GHz, multimode) furnaces at 1120 degrees C for 1 hour in forming gas (dissociated ammonia atmosphere, 95% N2-5% H2). The experimental results show that microwave sintered alloy has better properties compared with the conventionally sintered counterparts. Detailed analyses by using optical microscopy and scanning electron microscopy (SEM) reveal that microwave sintered sample has finer microstructure. SEM examination of the fractured surfaces indicate that a mixed mode fracture containing both, ductile and brittle types, is present in microwave sintered alloy, in contrast with the brittle fracture only in conventional sintered counterpart. PMID:24428106

  17. Uranium Ore Uranium is extracted

    E-print Network

    Milling of Uranium Ore Uranium is extracted from ore with strong acids or bases. The uranium is concentrated in a solid substance called"yellowcake." Chemical Conversion Plants convert the uranium in yellowcake to uranium hexafluoride (UF6 ), a compound that can be made into nuclear fuel. Enrichment

  18. New mechanism of the formation of the uranium-titanium association in ores of paleovalley deposits

    Microsoft Academic Search

    S. F. Vinokurov; M. V. Nesterova

    2010-01-01

    Uranium-titanium association in ores of paleoval? ley deposits demonstrates space and genetic control of uranium mineralization by clastogene iron-titanium oxides (typically modified ilmenites); this link is more preferable than that to carbonaceous matter and iron sulfides. Orebearing uranium-titanium association is most widely abundant in paleovalley deposits of North America (sandstone type) located in alluvial sandstone enriched in iron-titanium oxides with

  19. O-ring insertion tool

    NASA Astrophysics Data System (ADS)

    Zannini, Frank

    1991-09-01

    A tool for installing an O-ring in an inwardly facing O-ring groove in an electrical connection includes a guide shaft and a contact member slidably and rotatably received in the guide shaft. The guide shaft includes an elongated cylindrical shaft portion and a flared end portion on the shaft portion. The contact member includes an attachment portion for slidably and rotatably securing the contact member on the shaft portion and a contact finger on the attachment portion which extends in a direction toward the flared end portion of the guide shaft. The tool is operable by assembling an O-ring on the shaft portion between the flared end portion and the contact finger, inserting the flared end portion into a connection and then manipulating the contact member to advance the O-ring into an O-ring groove in the connector with the contact finger.

  20. REMOVAL OF ARSENIC FROM GROUNDWATER USING NATURALLY OCCURRING IRON OXIDES IN RURAL REGIONS OF MONGOLIA

    EPA Science Inventory

    We have found that the iron oxide particles produced by grinding naturally occurring iron ores are very effective in removing arsenic from water. The arsenic adsorption isothermal of the particles h...

  1. Sintering of fine oxide powders. 2: Sintering mechanisms

    SciTech Connect

    Chen, P.L.; Chen, I.W. [Univ. of Michigan, Ann Arbor, MI (United States)

    1997-03-01

    Conventional and new sintering mechanisms have been investigated using fine powders of CeO{sub 2} and Y{sub 2}O{sub 3} of excellent sinterability. The authors have verified the validity of Herring`s scaling law for 60--84% relative density and found that it is consistent with grain-boundary-diffusion control. At lower densities, they have found that pores larger than the critical size, in the sense of Kingery and Francois, can still be sintered readily. This is rationalized by a new sintering mechanism based on particle repacking concurrent with particle coarsening, resulting in a higher packing factor. Very fine, surface-active powders that coarsen rapidly are uniquely capable of taking advantage of this new sintering mechanism, which along with their propensity to homogenization, accounts for their remarkable sinterability even at very low green densities.

  2. Constrained Sintering Stress -Review

    NASA Astrophysics Data System (ADS)

    Taub, Samuel; Kim, Jung-Sik

    When a thin film is sintered on a rigid substrate, the film will become constrained in its plane. Densification can therefore only occur in one direction, that being perpendicular to the plane of the substrate. The constraint will lead to the development of an in-plane tensile stress in the film, which exactly opposes the tendency for shrinkage in the plane. The magnitude of these stresses has been of much technological interest.

  3. Sintered antifriction materials

    Microsoft Academic Search

    A. G. Kostornov; O. I. Fushchich

    2007-01-01

    Some classes of sintered antifriction materials that form the basis for the development of new materials are discussed. Metal-and\\u000a nonmetal-based materials with high wear resistance, low friction coefficient, and maximum lifetime are described. They differ\\u000a in composition, structure (microheterogeneous, macroheterogeneous, layered, fibrous), carrying capacity, and potential for\\u000a operation under various loads, at sliding rates, and in various conditions (high and

  4. Zone sintering of ceramic fuels

    DOEpatents

    Matthews, R. Bruce (Falls Church, VA); Chidester, Kenneth M. (Los Alamos, NM); Moore, H. Gene (Los Alamos, NM)

    1994-01-01

    Cold pressed UC.sub.2 fuel compacts are sintered at temperatures greater than about 1850.degree. C. while in contact with a sintering facilitator material, e.g., tantalum, niobium, tungsten or a metal carbide such as uranium carbide, thereby allowing for a reduction in the overall porosity and leaving the desired product, i.e., a highly dense, large-grained uranium dicarbide. The process of using the sintering facilitator materials can be applied in the preparation of other carbide materials.

  5. Leaching of aluminum and iron from boiler slag generated from a typical Chinese Steel Plant

    Microsoft Academic Search

    Jinping Li; Jinhua Gan; Xianwang Li

    2009-01-01

    This paper presents a new way of recycling aluminum and iron in boiler slag derived from coal combustion plants, which integrates efficient extraction and reuse of the leached pellets together. The boiler slag was pelletised together with washed coal and lime prior to sintering and then was sintered at 800–1200°C for different periods to produce sintered pellets for the leaching

  6. Upgrading Metals Via Direct Reduction from Poly-metallic Titaniferous Magnetite Ore

    NASA Astrophysics Data System (ADS)

    Samanta, Saikat; Mukherjee, Siddhartha; Dey, Rajib

    2015-02-01

    Pre-reduction is the thermo-chemical beneficiation process which is very useful technique for upgradation of metal values from complex low grade ore. The isothermal reduction behaviour of eastern Indian titaniferous magnetite lump ore without pre-treatment, pre-treated and ore-coke composite briquettes has been investigated in the present study. During pre-reduction of lump ore at 1473 K, magnetite and some part of ilmenite are transformed to metallic iron but most of the ilmenite has not reduced. Pre-treatment by multiple heating to high temperature (1373 K and 1473 K, respectively) and subsequently sudden cooling to room temperature by water successfully increase the porosity as well as many fissures in dense grain, which significantly enhance the degree of reduction. Ilmenite and magnetite phases are transformed to pseudobrookite and hematite during high temperature air soaking, and metallic iron is the dominant phase after reduction. Metallic iron and titanium dioxide are the major phases after reduction at 1373 K, but treatments above 1413 K lead to the formation of ferrous pseudobrookite (FeTi2O5). Finally, the different constitutes are separated by magnetic separation. The phases of reduced pre-treated and briquettes samples cannot be separated by magnetic separation, whereas reduced lump ore is separated successfully. The cause is perhaps due to association and interlocking of high intensity magnetic metallic iron with titanium oxide. Fe:TiO2 is upgraded about to 7.06:1 in the magnetic fraction of reduced lump ore which is formerly 2.14:1 in the case of raw ore. Vanadium is simultaneously distributed at a 3.81:1 ratio in magnetic and non-magnetic fraction.

  7. Mineral Phases and Release Behaviors of As in the Process of Sintering Residues Containing As at High Temperature

    PubMed Central

    Wang, Xingrun; Zhang, Fengsong; Nong, Zexi

    2014-01-01

    To investigate the effect of sintering temperature and sintering time on arsenic volatility and arsenic leaching in the sinter, we carried out experimental works and studied the structural changes of mineral phases and microstructure observation of the sinter at different sintering temperatures. Raw materials were shaped under the pressure of 10?MPa and sintered at 1000~1350°C for 45?min with air flow rate of 2000?mL/min. The results showed that different sintering temperatures and different sintering times had little impact on the volatilization of arsenic, and the arsenic fixed rate remained above 90%; however, both factors greatly influenced the leaching concentration of arsenic. Considering the product's environmental safety, the best sintering temperature was 1200°C and the best sintering time was 45?min. When sintering temperature was lower than 1000°C, FeAsS was oxidized into calcium, aluminum, and iron arsenide, mainly Ca3(AsO4)2 and AlAsO4, and the arsenic leaching was high. When it increased to 1200°C, arsenic was surrounded by a glass matrix and became chemically bonded inside the matrix, which lead to significantly lower arsenic leaching. PMID:24723798

  8. 2. Photocopied June 1978 'THE IRON DAM.' VIEW OF THE ...

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

    2. Photocopied June 1978 'THE IRON DAM.' VIEW OF THE IRON DAM, THE OUTCROPPING OF THE ORE FOUND IN 1826 BY HENDERSON. FURNISHED WATER TO SAWMILL. SOURCE: BENSON LOSSING, THE HUDSON, FROM THE WILDERNESS TO THE SEA, TROY, NEW YORK, 1866, p. 25 - Adirondack Iron & Steel Company, New Furnace, Hudson River, Tahawus, Essex County, NY

  9. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    United States. The majority of ore consumption was related to steel production, directly in pig iron: Domestic manganese demand was bolstered by increased raw steel production through at least the first one Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 1998

  10. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    United States. The majority of ore consumption was related to steel production, directly in pig iron.2 Electrolytic metal 9 0.5 9 2 1r Events, Trends, and Issues: Although raw steel production, a major determinant Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 1997

  11. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly 91 -- Ferromanganese, high-carbon 356 356 91 34 Events, Trends, and Issues: U.S. steel production Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  12. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    United States. The majority of ore consumption was related to steel production, directly in pig iron metal 10 0.02 10 2 Events, Trends, and Issues: A slight further advance in raw steel production Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 1996

  13. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly to affect the manganese market in 2009. U.S. steel production in 2009 was 40% less than that in 2008 Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  14. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly), coincided with the growth in the manganese market during 2010. U.S. steel production in 2010 was projected Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  15. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese has not been produced

    E-print Network

    Torgersen, Christian

    . Most ore consumption was related to steel production, directly in pig iron manufacture and indirectly, and Issues: U.S. steel production in 2012 was projected to be 4% more than that in 2011. Imports of manganese Production and Use: Manganese ore containing 35% or more manganese has not been produced domestically since

  16. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    and the Midwestern United States. Most ore consumption was related to steel production, directly in pig iron 2 Events, Trends, and Issues: Through September, steel production, the principal determinant Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 2002

  17. Anisotropy of magnetic susceptibility versus lattice-and shape-preferred orientation in the Lac Tio hemo-ilmenite ore body

    E-print Network

    Bascou, Jérôme

    Keywords: Magnetic fabric EBSD Image analysis Iron­titanium ore Anorthosite The Lac Tio hemo-ilmenite ore body crops out in the outer portion of the 1.06 Ga Lac Allard anorthosite, a member of the Havre-Saint-Pierre anorthosite suite from the Grenville province of North America. It is made up of ilmenitite (commonly

  18. Microwave sintering of multiple articles

    DOEpatents

    Blake, Rodger D. (Santa Fe, NM); Katz, Joel D. (Los Alamos, NM)

    1993-01-01

    Apparatus and method for producing articles of alumina and of alumina and silicon carbide in which the articles are sintered at high temperatures using microwave radiation. The articles are placed in a sintering container which is placed in a microwave cavity for heating. The rates at which heating and cooling take place is controlled.

  19. Microwave sintering of multiple aritcles

    SciTech Connect

    Blake, R.D.; Katz, J.D.

    1992-12-31

    Disclosed are apparatus and method for producing articles of alumina and of alumina and silicon carbide in which the articles are sintered at high temperatures using microwave radiation. The articles are placed in a sintering container which is placed in a microwave cavity for heating. The rates at which heating and cooling take place is controlled.

  20. Electrochemical processes in recovering metals from ores

    SciTech Connect

    Felker, D.L. (Hypalon Technical Polymer Product Dept., DuPont, Beaumont, TX (US)); Bautista, R.G. (Nevada Univ., Reno, NV (USA). Dept. of Chemical and Metallurgical Engineering)

    1990-04-01

    Chalcopyrite (CuFeS{sub 2}) is one of the most abundant copper-bearing minerals in the U.S. Oxidative leaching and smelting and refining are the most common methods used for recovering copper from chalcopyrite. One of the problems associated with oxidative leaching is the formation of an elemental sulfur product layer around the unreacted chalcopyrite core. The sulfur coating slows the reaction by inhibiting both the diffusion of the oxidant to the unreacted core, and the diffusion of the copper and iron species to the bulk solution. Another problem with leaching is that the iron and copper are oxidized simultaneously. Both appear in the bulk solution in their most oxidized states. The direct electrodissolution of copper sulfide ore slurries could reduce the number of steps involved in the copper recovery process, possibly leading to significant reductions in energy consumption and operating costs. The potential application of electrodissolution processes in hydrometallurgy has been reviewed. This paper reviews investigations of the electrochemical dissolution of chalcopyrite, digenite (Cu{sub 1.8}S), chalcocite (Cu{sub 2}S) and covellite (CuS).

  1. Siliceous sedimentary rock-hosted ores and petroleum

    SciTech Connect

    Hein, J.R.

    1987-01-01

    Geological, biological, oceanographic, and geochemical principles involved in forming mineral deposits associated with siliceous rocks are integrated in this collection. The book emerged from a decade of research by 142 scientists from 33 countries who worked with the International Geological Correlations Project under editor James R. Hein. It reveals how several economic ores and petroleum were formed in siliceous sediments in coastal ocean basins. This collection places each ore-deposit type into a genetic model emphasizing coastal upwelling; displays all chert occurrences on paleographic maps for each period of the Phanerozoic; covers phosphate, uranium, diatomite, manganese, iron, barite, and petroleum deposits; and gives the first evidence of a bacterially mediated, diagenetic origin for manganese deposits.

  2. Using tailings from the enrichment of zircon-ilmenite ores

    SciTech Connect

    Suleimenov, S.T.; Saibulatov, S.Zh.; Togzhanov, I.A.; Suleimenov, K.T.; Abdrakhimov, V.Z.; Vasil'chenko, N.A.

    1988-07-01

    X-ray methods, IR-spectroscopy, and microscopic techniques were used to investigate the phase inversions occurring during the firing of the clay part of the tailings from the gravitation enrichment of zircon-ilmenite ores from the Karotkel'sk deposit to evaluate the wastes as ceramic raw materials. Results showed the development of a liquid phase at a temperature below 950 C, intense crystallization of mullite at 1000-1050 C, the formation of a solid solution of the substitution type, replacing the mullite by oxides of iron and titanium, and the polymorphic inversion of beta-quartz to alpha-cristobalate. The properties of facing tiles from (%) 50 clay part of the KhGR ores, 30 light fraction ash and 20 wollastonite are shown and compared with the properties of tiles made from factory bodies of the Tselinogradsk ceramic combine.

  3. Properties of iron-graphite materials made with pencil graphite

    Microsoft Academic Search

    L. A. Zhukovskaya; Yu. F. Bokii; A. K. Gaiduchenko; A. G. Bol' shechenko; I. D. Zinchenko

    1969-01-01

    1.The nature of the variation of the mechanical properties and hardness of iron-graphite compositions has been determined as a function of sintering temperature and it was shown that its mechanical properties and hardness increase nonlinearly with the sintering temperature. If the sintering temperature is lowered, the strength curve becomes more parabolic and the degree of curvature increases.2.The nature of the

  4. Magmatic Conduit Metallogenic System - A New Model for the Origin of Ore-deposits

    NASA Astrophysics Data System (ADS)

    Su, S.; Tang, Z.; Wu, G.; Deng, J.; Xiao, Q.; Luo, Z.; Cui, Y.

    2013-12-01

    Origin and emplacement processes of ore-deposits connected with intrusions remains poorly understood. Here we propose a new model 'Magmatic Conduit Metallogenic System' to explain the origin of ore-deposits. Magmatic flow (or Melt-fluid flow) bearing metals will finally settle in the conduits at later stage of magma evolved in magma metallogenic system. Magmatic flow (or Melt-fluid flow) bearing metals include many types, such as sulfide melts and iron melts bearing fluids. Conduits will form along the zones of structural weakness, such as fault zone and interface of two different types of rocks. These conduits are usually very complicated in the magmatic system, exemplified by two typical ore-deposits, detailed as follows. The Jinchuan sulfide deposit, located in Gansu Province, China, is the third largest magmatic Cu-Ni Platinum Group Elements (PGE) in the world. There are mainly four orebodies (orebody 58, 24, 1, and 2) from west to east, with Ni/Cu value at 1.24, 1.56, 1.83 and 2.06 respectively; the content of Pt+Pd ranges from 0.4 to 10.3 ppm, with the highest value occurs in the west. This suggests that the direction of the melt flow bearing sulfide is from west to east and the front of the conduit system is in the east part of the deposit. Sulfide segregation in the magmatic chamber or in the conduits might have caused ore content to change in different part of the conduit systems. Another typical example is the Xishimen iron deposit, which is located in the South of Hebei Province, China. It has been considered as a skarn-type iron deposit conventionally. However, many geological evidence suggests that Xishimen iron deposit is a magmatic iron deposit instead. Such evidence includes: 1. The boundaries between iron orebodies and country rocks are obvious, no transitional relationship; 2. Iron ore body injected into the country rocks (including genesis, diorite, and marble); 3. There are some vesicular in the iron ores; 4. Magnetite as an interstitial mineral occurs among the pyroxenes/amphiboles. The content of titanium in the iron ores changes from 0.14% to 0.20 wt. % gradually from southeast to northwest (NW), suggesting the direction of melt-fluid flow bearing iron is from SE to NW. These characteristics in the Xishimen iron deposit indicate that melt-fluid flow bearing iron controls the distribution of iron orebodies. Several key points in 'Magmatic Conduit Metallogenic System' are concluded here: 1. All melt or melt-fluid bearing metals formed in the staging chamber are finally settled in the conduits based on their differences in density; 2. We can determine the direction of the melt or melt-fluid flow according to the content and textures of ores in the conduits. We propose that 'Magmatic Conduit Metallogenic System' could serve as a new exploring model for the ore-deposits connected with intrusions.

  5. Bog iron formation in the Nassawango Creek watershed, Maryland, USA

    USGS Publications Warehouse

    Bricker, O.P.; Newell, W.L.; Simon, N.S.

    2004-01-01

    The Nassawango bog ores in the modern environment for surficial geochemical processes were studied. The formation of Nassawango bog ores was suggested to be due to inorganic oxidation when groundwater rich in ferrous iron emerges into the oxic, surficial environment. It was suggested that the process, providing a phosphorus sink, may be an unrecognized benefit for mitigating nutrient loading from agricultural lands. It is found that without the effect of iron fixing bacteria, bog deposites could not form at significant rates.

  6. Nutrient Effect on the Biological Leaching of a Black-Schist Ore

    PubMed Central

    Niemelä, Seppo I.; Riekkola-Vanhanen, Marja; Sivelä, Carita; Viguera, Felipe; Tuovinen, Olli H.

    1994-01-01

    The purpose of the study was to examine the influence of inorganic N (NH4+, NO3-) and phosphate on the biological oxidation of a sulfidic black-schist ore which contained pyrrhotite as the main iron sulfide. Iron was initially solubilized as Fe2+ from the ore and subsequently oxidized to Fe3+ in shake flask experiments. Under these experimental conditions, iron dissolution from pyrrhotite was mainly a chemical reaction, with some enhancement by bacteria, whereas the subsequent Fe2+ oxidation was bacterially mediated, with negligible contribution from chemical oxidation. Phosphate amendment did not enhance Fe2+ oxidation. Chemical analysis of leach solutions with no exogenous phosphate revealed that phosphate was solubilized from the black-schist ore. Ammonium amendment (6 mM) enhanced Fe2+ oxidation, whereas the addition of nitrate (6 and 12 mM) had a negative effect. An increase in the temperature from 30 to 35°C slightly enhanced Fe2+ oxidation, but the effect was statistically not significant. The precipitation of potassium jarosite was indicative of Fe2+ oxidation and was absent in nitrate-inhibited cultures because of the lack of Fe2+ oxidation. The black-schist ore also contained phlogopite, which was altered to vermiculite in iron-oxidizing cultures. PMID:16349236

  7. The effects of mineralogy on the biological leaching of nickel laterite ores

    Microsoft Academic Search

    M. Valix; J. Y. Tang; W. H. Cheung

    2001-01-01

    The amenability of limonite ore, the iron rich nickel laterite phase, was observed to be less than saprolite, the silicate rich phase, when subjected to biological leaching with heterotrophic microorganisms. To understand this difference, controlled leaching of the various nickel laterite minerals was conducted using citric acid to mimic the chemical action of the organisms and subsequent characterisation of the

  8. Utilizing a Value of Information Framework to Improve Ore Collection and Classification Procedures

    E-print Network

    decisions and increase the overall profitability of the mine. This case study provides a framework of information methodology to analyze a mine company's decision to purchase ore grade scanners. We demonstrate-term contractual agreements. The Loussavaara-Kiirunavarra Aktiebolag (LKAB) company operates an underground iron

  9. [Structural changes in mineral phases and environmental release behavior of arsenic during sintering of arsenic-containing waste].

    PubMed

    Wang, Xing-Run; Nong, Ze-Xi; Wang, Qi

    2012-12-01

    An experimental work was carried out to investigate the effect of sintering temperature on arsenic volatility, arsenic leaching of the sinter and structural changes in mineral phases of arsenic in the sinter. The raw materials were shaped under the pressure of 10 MPa and sintered at 1 000-1 350 degrees C for 60 min with the air flow rate of 2 000 mL x min(-1). The results showed that there was little impact between the volatilization of arsenic before and after sintering, and arsenic fixed-rate remained above 90%, however, the sintering temperature had an important influence on the leaching concentration of arsenic. When sintering temperature was lower than 1 000 degrees C, FeAsS was oxidized into calcium arsenate, aluminum arsenate, and iron-arsenate. Ca3 (AsO4)2 was the main compound, and the release of arsenic leaching was high. When sintering temperature was up to 1 200 degrees C, the arsenic was surrounded by a glass matrix and became chemically bonded inside the matrix. Arsenates can be converted into silicoarsenates during sintering, which led to the leaching of arsenic was significantly lower. Considering the product's environmental safety, the best sintering temperature was 1 200 degrees C. PMID:23379173

  10. Heap bioleaching of a complex sulfide ore: Part II. Effect of temperature on base metal extraction and bacterial compositions

    Microsoft Academic Search

    Anna-Kaisa Halinen; Nelli Rahunen; Anna H. Kaksonen; Jaakko A. Puhakka

    2009-01-01

    The effect of low to moderate temperatures (7 to 50 °C) on the bioleaching of a low-grade, multi-metal black schist ore from Finland in which pentlandite was the main valuable mineral, was studied using columns at set temperatures. The iron and sulfur-oxidizing microbial culture used were enriched from the ore deposit water samples. At 7 °C and 21 °C, the leach liquor redox

  11. ORE POLYNOMIALS IN SAGE MANUEL KAUERS

    E-print Network

    Schneider, Carsten

    ORE POLYNOMIALS IN SAGE MANUEL KAUERS , MAXIMILIAN JAROSCHEK , FREDRIK JOHANSSON Abstract. We present a Sage implementation of Ore algebras. The main features for the most common instances include an implementation of a collection of algorithms related to Ore algebras for the computer algebra system Sage [14

  12. O-ring gasket test fixture

    NASA Technical Reports Server (NTRS)

    Turner, James Eric (inventor); Mccluney, Donald Scott (inventor)

    1991-01-01

    An apparatus is presented for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring.

  13. Recovery of sulfur from native ores

    SciTech Connect

    Womack, J.T.; Wiewiorowski, T.K.; Astley, V.C.; Perez, J.W.; Headington, T.A.

    1992-03-17

    This patent describes a process for removing elemental sulfur from ores containing elemental sulfur. It comprises crushing a sulfur-containing ore to a coarse particle size wherein ore particles produced during crushing enable substantially all of the sulfur to be liberated during a heating step and to produce an ore gangue that is substantially not susceptible to flotation: forming an aqueous ore slurry containing about 50-80% by weight of solids from the crushed ore and adjusting the pH to at least a pH of about 8.0; heating the aqueous ore slurry formed in step (b) under elevated pressure to a temperature of about 240{degrees} - 315{degrees} F. for sufficient time to melt and liberate elemental sulfur contained in the ore to produce liberated molten sulfur and ore gangue, wherein the slurry is heated while agitating the slurry at sufficient velocity to substantially maintain the ore, ore gangue and liberated molten sulfur in suspension; cooling the heated slurry sufficiently to resolidify the liberated molten sulfur; conditioning the aqueous slurry of step (d) with a flotation aid; separating the condition aqueous slurry of ore gangue and resolidified sulfur in a flotation unit to produce a sulfur-rich flotation concentrate overstream; and recovering the sulfur-rich flotation concentrate and separating the sulfur therefrom.

  14. Improving the production of chrome sinter

    Microsoft Academic Search

    E. V. Maksimov; M. F. Vitushchenko; I. A. Verner; B. N. Nurmaganbetova; A. K. Torgovets; Zh. O. Nurmaganbetov

    2010-01-01

    The chemical and mineralogical composition of sintering batch is determined by chemical and differential thermal analysis.\\u000a Local clay is found to melt at the lowest temperatures and may be used to obtain chrome sinter. Mathematical modeling of the\\u000a sintering of chrome fines permits the determination of the optimal sintering parameters. On the basis of this research, high-quality\\u000a chrome sinter is

  15. Ceramic powder for sintering materials

    NASA Technical Reports Server (NTRS)

    Akiya, H.; Saito, A.

    1984-01-01

    Surface activity of ceramic powders such as MgO and Al2O3, for use in sintering with sp. emphasis on their particle size, shape, particle size distribution, packing, and coexisting additives and impurities are reviewed.

  16. Method of sintering ceramic materials

    DOEpatents

    Holcombe, Cressie E. (Knoxville, TN); Dykes, Norman L. (Oak Ridge, TN)

    1992-01-01

    A method for sintering ceramic materials is described. A ceramic article is coated with layers of protective coatings such as boron nitride, graphite foil, and niobium. The coated ceramic article is embedded in a container containing refractory metal oxide granules and placed within a microwave oven. The ceramic article is heated by microwave energy to a temperature sufficient to sinter the ceramic article to form a densified ceramic article having a density equal to or greater than 90% of theoretical density.

  17. Sintering theory for crystalline solids

    SciTech Connect

    Searcy, A.W.

    1986-11-01

    A thermodynamic model for vacancy partitioning among sites of different bonding environments, yields a more satisfactory expression for the driving forces for sintering and for grain growth at constant temperature than traditional theories. This expression is shown to be also a logical consequence of classical thermodynamic theory for faceted particles. Then the driving force for sintering in a temperature gradient is evaluated in terms of gradients in equilibrium vapor pressures. 26 refs., 6 figs.

  18. Viscous sintering of volcanic ash

    NASA Astrophysics Data System (ADS)

    Wadsworth, F. B.; Scheu, B.; Vasseur, J.; Tuffen, H.; von Aulock, F. W.; Lavallée, Y.; Hess, K. U.; Dingwell, D. B.

    2014-12-01

    Volcanic ash is often deposited in a hot state. Volcanic ash containing glass, deposited above the glass transition interval, has the potential to sinter viscously both to itself (particle-particle) and to exposed surfaces. Here, we constrain the kinetics of this process experimentally under isothermal and non-isothermal conditions using standard glasses and volcanic ash. In the absence of external load, this process is dominantly driven by surface relaxation. In such cases the sintering process is rate-limited by the melt viscosity, the size of the particles and the melt-vapour interfacial tension. We propose a polydisperse continuum model that describes the transition from a packing of particles to a dense pore-free melt and evaluate its efficacy in describing the kinetics of volcanic viscous sintering. We apply our model to viscous sintering scenarios for cooling crystal-poor rhyolitic ash using the 2008 eruption of Chaitén volcano as a case example. We predict that moderate cooling rates result in the common observation of incomplete sintering and the preservation of pore networks. Finally we discuss the effect of crystallisation, external loading and volatile degassing or regassing during viscous sintering and assert that such complexities must be considered in the volcanic scenario.

  19. Magnetization curves of sintered heavy tungsten alloys for applications in MRI-guided radiotherapy

    SciTech Connect

    Kolling, Stefan [Sydney Medical School, University of Sydney, NSW 2006 (Australia)] [Sydney Medical School, University of Sydney, NSW 2006 (Australia); Oborn, Bradley M. [Illawarra Cancer Care Centre (ICCC), Wollongong, NSW 2500, Australia and Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2500 (Australia)] [Illawarra Cancer Care Centre (ICCC), Wollongong, NSW 2500, Australia and Centre for Medical Radiation Physics (CMRP), University of Wollongong, Wollongong, NSW 2500 (Australia); Keall, Paul J., E-mail: paul.keall@sydney.edu.au [Sydney Medical School, University of Sydney, NSW 2006, Australia and Ingham Institute for Applied Medical Research, Liverpool, NSW 2170 (Australia); Horvat, Joseph [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2500, Australia and School of Physics, University of Wollongong, Wollongong, NSW 2500 (Australia)] [Institute for Superconducting and Electronic Materials, University of Wollongong, Wollongong, NSW 2500, Australia and School of Physics, University of Wollongong, Wollongong, NSW 2500 (Australia)

    2014-06-15

    Purpose: Due to the current interest in MRI-guided radiotherapy, the magnetic properties of the materials commonly used in radiotherapy are becoming increasingly important. In this paper, measurement results for the magnetization (BH) curves of a range of sintered heavy tungsten alloys used in radiation shielding and collimation are presented. Methods: Sintered heavy tungsten alloys typically contain >90?% tungsten and <10?% of a combination of iron, nickel, and copper binders. Samples of eight different grades of sintered heavy tungsten alloys with varying binder content were investigated. Using a superconducting quantum interference detector magnetometer, the induced magnetic momentm was measured for each sample as a function of applied external field H{sub 0} and the BH curve derived. Results: The iron content of the alloys was found to play a dominant role, directly influencing the magnetizationM and thus the nonlinearity of the BH curve. Generally, the saturation magnetization increased with increasing iron content of the alloy. Furthermore, no measurable magnetization was found for all alloys without iron content, despite containing up to 6% of nickel. For two samples from different manufacturers but with identical quoted nominal elemental composition (95% W, 3.5% Ni, 1.5% Fe), a relative difference in the magnetization of 11%–16% was measured. Conclusions: The measured curves show that the magnetic properties of sintered heavy tungsten alloys strongly depend on the iron content, whereas the addition of nickel in the absence of iron led to no measurable effect. Since a difference in the BH curves for two samples with identical quoted nominal composition from different manufacturers was observed, measuring of the BH curve for each individual batch of heavy tungsten alloys is advisable whenever accurate knowledge of the magnetic properties is crucial. The obtained BH curves can be used in FEM simulations to predict the magnetic impact of sintered heavy tungsten alloys.

  20. Massive deep-sea sulphide ore deposits discovered on the East Pacific Rise

    USGS Publications Warehouse

    Francheteau, Jean; Needham, H.D.; Choukroune, P.; Juteau, Tierre; Seguret, M.; Ballard, Richard D.; Fox, P.J.; Normark, William; Carranza, A.; Cordoba, D.; Guerrero, J.; Rangin, C.; Bougault, H.; Cambon, P.; Hekinian, R.

    1979-01-01

    Massive ore-grade zinc, copper and iron sulphide deposits have been found at the axis of the East Pacific Rise. Although their presence on the deep ocean-floor had been predicted there was no supporting observational evidence. The East Pacific Rise deposits represent a modern analogue of Cyprus-type sulphide ores associated with ophiolitic rocks on land. They contain at least 29% zinc metal and 6% metallic copper. Their discovery will provide a new focus for deep-sea exploration, leading to new assessments of the concentration of metals in the upper layers of the oceanic crust. ?? 1979 Nature Publishing Group.

  1. Method of making bonded or sintered permanent magnets

    DOEpatents

    McCallum, R.W.; Dennis, K.W.; Lograsso, B.K.; Anderson, I.E.

    1993-08-31

    An isotropic permanent magnet is made by mixing a thermally responsive, low viscosity binder and atomized rare earth-transition metal (e.g., iron) alloy powder having a carbon-bearing (e.g., graphite) layer thereon that facilitates wetting and bonding of the powder particles by the binder. Prior to mixing with the binder, the atomized alloy powder may be sized or classified to provide a particular particle size fraction having a grain size within a given relatively narrow range. A selected particle size fraction is mixed with the binder and the mixture is molded to a desired complex magnet shape. A molded isotropic permanent magnet is thereby formed. A sintered isotropic permanent magnet can be formed by removing the binder from the molded mixture and thereafter sintering to full density.

  2. Method of making bonded or sintered permanent magnets

    DOEpatents

    McCallum, R.W.; Dennis, K.W.; Lograsso, B.K.; Anderson, I.E.

    1995-11-28

    An isotropic permanent magnet is made by mixing a thermally responsive, low viscosity binder and atomized rare earth-transition metal (e.g., iron) alloy powder having a carbon-bearing (e.g., graphite) layer thereon that facilitates wetting and bonding of the powder particles by the binder. Prior to mixing with the binder, the atomized alloy powder may be sized or classified to provide a particular particle size fraction having a grain size within a given relatively narrow range. A selected particle size fraction is mixed with the binder and the mixture is molded to a desired complex magnet shape. A molded isotropic permanent magnet is thereby formed. A sintered isotropic permanent magnet can be formed by removing the binder from the molded mixture and thereafter sintering to full density. 14 figs.

  3. Method of making bonded or sintered permanent magnets

    DOEpatents

    McCallum, R. William (Ames, IA); Dennis, Kevin W. (Ames, IA); Lograsso, Barbara K. (Ames, IA); Anderson, Iver E. (Ames, IA)

    1995-11-28

    An isotropic permanent magnet is made by mixing a thermally responsive, low viscosity binder and atomized rare earth-transition metal (e.g., iron) alloy powder having a carbon-bearing (e.g., graphite) layer thereon that facilitates wetting and bonding of the powder particles by the binder. Prior to mixing with the binder, the atomized alloy powder may be sized or classified to provide a particular particle size fraction having a grain size within a given relatively narrow range. A selected particle size fraction is mixed with the binder and the mixture is molded to a desired complex magnet shape. A molded isotropic permanent magnet is thereby formed. A sintered isotropic permanent magnet can be formed by removing the binder from the molded mixture and thereafter sintering to full density.

  4. Sintering characteristics of Fe and FeCo alloy ultrafine powders

    Microsoft Academic Search

    Y. Sakka; T. Uchikoshi; E. Ozawa

    1993-01-01

    Sintering characteristics of three kinds of iron and FeCo alloy ultrafine powders (UFPs) in vacuum and a hydrogen atmosphere were examined by continuously measuring their dimensions, and observing their structural changes. The UFPs exposed to air contain mixtures of oxide and hydroxide phases. The oxide phase increased during heating in vacuum. The compacts of the UFPs shrunk slightly at temperatures

  5. Effect of fillers in lubricating oil and of structure on the operating performance of parts from sintered materials

    Microsoft Academic Search

    A. M. Avakov; É. N. Popov; I. B. Saiko; Yu. I. Pustovoit; L. P. Brener; V. K. Krivonosov

    1978-01-01

    1.The useful life of a self-lubricating sintered part from an iron powder can be substantially increased by introducing a polymer and graphite into the lubricant and from 1 to 1.5 wt.% graphite into the starting charge.2.In the absence of an external lubricant supply the operating performance of a system composed of a sintered skeleton and a filler depends mainly on

  6. Cold and hot deformation and densification studies on sintered Fe-C-Cr-Ni low alloy P\\/M steels

    Microsoft Academic Search

    D. Shanmugasundaram; R. Chandramouli; T. K. Kandavel

    2009-01-01

    The present research work pertains to the study of the densification behaviour of sintered low alloy P\\/M steels with Ni and\\u000a Cr during cold and hot deformation processing. Elemental powders of atomized iron, graphite, chromium and nickel were mixed\\u000a in suitable proportions using a ball mill, compacted and sintered in order to yield the following alloy compositions: Fe-0.2%\\u000a C, Fe-0.2%

  7. The seal reliability analysis of oring seals

    Microsoft Academic Search

    Faguo Sun; Tianxiang Yu; Weimin Cui; Xiao Zong

    2009-01-01

    First, the seal reliability function of the O-ring, that is the maximum contact stress between O-ring and plunger must be greater than the fluid pressure, is established, then on the basis of the nonlinear constitutive equation Mooney-Rivlin of rubber material, the finite element model of the O-ring is built using commercial software ABAQUS, according to the finite element model, the

  8. Tourmaline in the central Swedish ore district

    Microsoft Academic Search

    R. H. Hellingwerf; K. Gatedal; V. Gallagher; J. H. Baker

    1994-01-01

    More than 40 recently discovered tourmaline occurrences have been investigated in the Mid-Proterozoic Bergslagen ore district of central Sweden. Some are spatially associated with ores, others with zones of leaching, remobilization and migmatization. Among the tourmaline-bearing ore deposits are the Dammberg ZnPb-Fe sulphide deposit, the Sala Pb-Zn-Ag deposit, the Dalkarlsberg, Pershyttan and Håksberg Fe oxide deposits, the Leja Cu deposit,

  9. Making low-alloy steel from phosphorus pig iron

    Microsoft Academic Search

    P. S. Kharlashin; O. V. Nosochenko; E. A. Ivanov; V. I. Ganoshenko; V. M. Baklanskii

    1991-01-01

    In order to expand the range of grades of converter steel that can be made from arsenic-bearing phosphorus pig iron, attempts have been made to convert pig iron from Kerchensk ores to quality low-alloy steel by a technology developed at the \\

  10. A Linear Programming Model of Integrated Iron and Steel Production

    Microsoft Academic Search

    Tibor Fabian

    1958-01-01

    Integrated steel mills usually have a choice over the use of various materials and production processes. Different ores may be used in the production of iron; steel scrap and iron can be used in different proportions in the production of steel. The economical usage rate of all materials is a function of numerous variables, among which the market price of

  11. Environmental impact of mining activity in the Rud?any Ore Field, Slovak Ore Mountains

    Microsoft Academic Search

    Peter Bajtoš

    The Rud?any Ore Field is known by the long-run underground exploitation of Fe, Cu, BaSO4 and Hg ore fixed on the ore veins. Mining activity caused a significant intervention on environmental conditions in this area. The worked-out spoils were stacked near the shafts, where make the expressive morphological elements - pit tips. Through blows the mined-out parts of ore veins

  12. Optimization of flotation variables for the recovery of hematite particles from BHQ ore

    NASA Astrophysics Data System (ADS)

    Rath, Swagat S.; Sahoo, Hrushikesh; Das, B.

    2013-07-01

    The technology for beneficiation of banded iron ores containing low iron value is a challenging task due to increasing demand of quality iron ore in India. A flotation process has been developed to treat one such ore, namely banded hematite quartzite (BHQ) containing 41.8wt% Fe and 41.5wt% SiO2, by using oleic acid, methyl isobutyl carbinol (MIBC), and sodium silicate as the collector, frother, and dispersant, respectively. The relative effects of these variables have been evaluated in half-normal plots and Pareto charts using central composite rotatable design. A quadratic response model has been developed for both Fe grade and recovery and optimized within the experimental range. The optimum reagent dosages are found to be as follows: collector concentration of 243.58 g/t, dispersant concentration of 195.67 g/t, pH 8.69, and conditioning time of 4.8 min to achieve the maximum Fe grade of 64.25% with 67.33% recovery. The predictions of the model with regard to iron grade and recovery are in good agreement with the experimental results.

  13. Spark Plasma Sintering (SPS) of NASICON Ceramics

    Microsoft Academic Search

    Ji-Sun Lee; Chae-Myung Chang; Young IL Lee; Jong-Heun Lee; Seong-Hyeon Hong

    2004-01-01

    Spark plasma sintering (SPS) method was used to obtain dense NASICON ceramics with a high-electrical conductivity, which was compared with conventional solid-state sintering. The fully dense NASICON was achieved at a relatively low- sintering temperature of 1100°C, whereas the apparent density of the specimen prepared by conventional sintering was 74% of the theoretical density. The highest conductivity of 1.8 103

  14. Measuring Elastic Modulus of Sintered Metal

    NASA Technical Reports Server (NTRS)

    Fedors, R. F.; Eastman, A. F.

    1983-01-01

    Technique minimizes effect of substrate on thin sintered coating. Uniaxial tension test yields approximate value for elastic modulus of sintered material on thin substrate. Electrode composed of central perforated nickel plated steel sheet about 4 mils (0.1mm) thick, coated on each face by porous sintered nickel about 8 mils (0.2mm) thick.

  15. Dislocation generation during early stage sintering.

    NASA Technical Reports Server (NTRS)

    Sheehan, J. E.; Lenel, F. V.; Ansell, G. S.

    1973-01-01

    Discussion of the effects of capillarity-induced stresses on dislocations during early stage sintering. A special version of Hirth's (1963) theoretical calculation procedures modified to describe dislocation nucleation on planes meeting the sintering body's neck surface obliquely is shown to predict plastic flow at stress levels know to exist between micron size metal particles in the early stages of sintering.

  16. Resins and asphaltenes in sintering petroleum coke

    Microsoft Academic Search

    E. V. Koshkarov; P. G. Danilyan; V. Ya. Koshkarov

    1987-01-01

    One of the directions in utilization of sintering coke breeze that may be effective is its addition to a coal or coal briquet charge to coke ovens in place of sintering and weakly sintering coals in coal-tar chemical production. For their investigation they took commercial samples of petroleum coke breeze (0-25 mm) obtained from different types of raw material: (1)

  17. Microwave hybrid fast sintering of porcelain bodies

    Microsoft Academic Search

    Romualdo R. Menezes; Pollyane M. Souto; Ruth. H. G. A. Kiminami

    2007-01-01

    Microwave heating offers many advantages over conventional heating methods, such as saving energy, very rapid heating rates and considerably reduced processing times. However, few studies have used microwave energy to sinter traditional ceramics. Thus, the aim of this work is microwave hybrid fast sintering of porcelain bodies. Bodies of sanitary ware, dental and electrical porcelain were sintered quickly. The control

  18. Sintering of tungsten powder with and without tungsten carbide additive by field assisted sintering technology

    Microsoft Academic Search

    S. Chanthapan; A. Kulkarni; J. Singh

    Tungsten powder (0.6–0.9?m) was sintered by field assisted sintering technology (FAST) at various processing conditions. The sample sintered with in-situ hydrogen reduction pretreatment and pulsed electric current during heating showed the lowest amount of oxygen. The maximum relative density achieved was 98.5%, which is from the sample sintered at 2000°C, 85MPa for 30min. However, the corresponding sintered grain size was

  19. Microwave sintering of boron carbide

    DOEpatents

    Blake, R.D.; Katz, J.D.; Petrovic, J.J.; Sheinberg, H.

    1988-06-10

    A method for forming boron carbide into a particular shape and densifying the green boron carbide shape. Boron carbide in powder form is pressed into a green shape and then sintered, using a microwave oven, to obtain a dense boron carbide body. Densities of greater than 95% of theoretical density have been obtained. 1 tab.

  20. Who invented the O-ring?

    Microsoft Academic Search

    Allan A. Mills

    1996-01-01

    As a commercial product the O-ring is ideal: simple, effective, and easily mass-produced; yet hard to make oneself on a one-off basis. With so many millions in past and present use the inventor of the O-ring deserves to be both rich and famous, but in fact the origin of the device is far from clear.

  1. Determining impact routes for sulfide ore transportation

    E-print Network

    Chow, Tzeekiu Edwin

    Determining impact routes for sulfide ore transportation Objective: To identify least cost/impact routes based on given parameters (population, federal land, wild life preserves) for transport of sulfide to the Kirtland's Warbler and a rare breeding population of brook trout. Sulfide ores exposed to the air

  2. Direct Flotation of Niobium Oxide Minerals from Carbonatite Niobium Ores

    NASA Astrophysics Data System (ADS)

    Ni, Xiao

    Currently the recovery of niobium oxide minerals from carbonatite niobium ores relies on the use of non-selective cationic collectors. This leads to complicated process flowsheets involving multiple desliming and multiple reverse flotation stages, and low niobium recovery. In this research, anionic collectors that are capable of strong chemisorption on the niobium minerals were studied with the objective of directly floating the niobium oxide minerals from the carbonatite ores. In the flotation of both high purity minerals and Niobec ores, it was shown that the combination of hydroxamic acid and sodium metaphosphate was an effective reagent scheme for the direct flotation of niobium oxide from its ores. Batch flotation on the Niobec Mill Feed showed that over 95% of niobium oxide was recovered into a rougher concentrate that was less than 47% of the original feed mass. Preliminary cleaning tests showed that the reagent scheme could also be used to upgrade the rougher concentrate, although the depression of iron oxide minerals required further study. X-ray photoelectron spectroscopic (XPS) measurement results confirm that OHA (octyl hydroxamic acid) could chemisorb on pyrochlore surface while only physically adsorb on calcite, judging by the chemical shifts of electron binding energies in the elements in both OHA and the mineral surfaces. When hydroxamic acid was adsorbed on calcite surface, the binding energies of the N 1s electrons, at 400.3 eV, did not shift. However, after adsorption on pyrochlore, the N 1s binding energy peak split into two peaks, one at a binding energy of around 399 eV, representing chemically adsorbed OHA, the other at between 400 and 401 eV. The experimental data suggested a strong chemisorption of the OHA on pyrochlore surface in the form of a vertical head-on orientation of the OHA molecules so that the pyrochlore was strongly hydrophobized even at low OHA concentrations, followed by possibly randomly oriented physisorbed OHA molecules. On the other hand, OHA only physisorbed on calcite forming a horizontally oriented monolayer of OHA. The results explain the observed selectivity of hydroxamic acid in the flotation of niobium oxide minerals from carbonatite niobium ores.

  3. Liquefaction of bituminous coals using disposable ore catalysts and hydrogen. Final report, February 7, 1982-July 31, 1982

    SciTech Connect

    Mathur, V.K.

    1982-09-01

    There are a number of problems associated with the production of liquid fuels from coal. The most complex is the use of commercial catalysts which are expensive, with short life, and cannot be recovered or regenerated. The objective of this study was to conduct experiments on coal hydrogenation using low cost mineral ores as disposable catalysts. Coal samples from Blacksville Mine, Pittsburgh Bed were hydrogenated using a number of ores, ore concentrates and industrial waste products as catalysts. Experiments were also conducted using a commercial catalyst (Harshaw Chemicals, 0402T) and no catalyst at all to compare the results. Since iron pyrite has been reported to be a good disposable catalyst, experiments were also conducted using pyrite individually as well as in admixture with other ores or concentrates. The liquefaction was conducted at 425/sup 0/C under 2000 psig (13,790 kPa) hydrogen pressure for a reaction time of 30 minutes using SRC-II heavy distillate as a vehicle oil. The conclusions of this study are as follows: (a) Results of liquefaction using two cycle technique showed that the catalytic activity of iron pyrite could be enhanced by adding materials like limonite, laterite or red mud. Iron pyrite in admixture with limonite ore or molybdenum oxide concentrate gave the best results among all the binary mixtures studied. (b) Iron pyrite with molybdenum oxide concentrate and cobaltic hydroxide cake (metal loading in each case the same as in Harshaw catalyst) gave results which compared favorably with those obtained using the Harshaw catalyst. It is recommended that work on this project should be continued exploring other ores and their mixtures for their catalytic activity for coal liquefaction.

  4. 77 FR 44146 - Approval and Promulgation of Air Quality Implementation Plans; Maryland; Control of Iron and...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-07-27

    ...Maryland; Control of Iron and Steel Production Installations; Sintering Plants AGENCY...regulation for the Control of Iron and Steel Production Installations only as they apply to...regulation for the Control of Iron and Steel Production Installations contingent upon the...

  5. Prediction of Elastic Behavior of Sintered Metal Powder from the Ultrasonic Velocities of Green Compacts

    NASA Astrophysics Data System (ADS)

    Phani, K. K.; Sanyal, Dipayan

    2008-04-01

    A novel procedure for the estimation of the elastic properties of the sintered and compacted metal powders from the ultrasonic velocities of the green compact alone has been proposed in this article. The methodology has been validated for sintered iron powder and copper powder compacts as well as for consolidated silver powder compacts of various processing histories, powder sizes, and pore morphology. The predicted elastic moduli, including the derived modulus (Poisson’s ratio), are found to be in reasonably good agreement with the measured data reported in the literature. The proposed method can be developed as a potent tool for the quantitative nondestructive evaluation (QNDE) of powder metallurgy products.

  6. Application of solution-mineral equilibrium chemistry to solution mining of uranium ores

    Microsoft Academic Search

    A. C. Riese; C. J. Propp

    1980-01-01

    Modern methods of uranium solution mining are typically accompanied by gains and losses of mass through reagent consumption by rock-forming minerals, with subsequent formation of clay minerals, gypsum, carbonates, and iron oxyhydroxides. A systematic approach to alleviate such problems involves the application of leach solutions that are in equilibrium with the host-rock minerals but in disequilibrium with the ore-forming minerals.

  7. A kinetic study of the leaching of a Nigerian ilmenite ore by hydrochloric acid

    Microsoft Academic Search

    Edward Olanipekun

    1999-01-01

    A kinetic study of the leaching of powdered ilmenite ore by hydrochloric acid has been investigated. The effects of (a) stirring speed ranging from 100 to 500 min?1, (b) particle size ranging from 20 to 74 ?m, (c) acid concentration ranging from 7.2 to 9.6 M and (d) temperature ranging from 70 to 90°C on titanium and iron dissolution are

  8. Iron impurities in Si3N4 processing

    NASA Technical Reports Server (NTRS)

    Bouldin, C. E.; Stern, E. A.; Donley, M. S.; Stoebe, T. G.

    1985-01-01

    The atomic environment of iron impurities is investigated during the processing cycle of reaction-bonding silicon nitride (RBSN). Several analysis techniques are utilized, including X-ray photoelectron spectroscopy (XPS), extended X-ray absorption fine structure (EXAFS), and electron spin resonance (ESR), to examine iron impurities in the starting silicon powder, in sintered silicon compacts, and in RBSN materials. Results indicate that iron impurities in as-received metallurgical grade silicon powder are incorporated in the silicon bulk as a highly distorted FeSi2 compound. No surface iron or iron-based particulate is observed in the starting material. Upon sintering, the iron environment becomes an ordered FeSi2 structure. In the RBNS material, the FeSi2 structure is again distorted, as observed by both EXAFS and ESR.

  9. Principles of laser micro sintering

    Microsoft Academic Search

    P. Regenfuss; A. Streek; L. Hartwig; S. Klötzer; Th. Brabant; M. Horn; R. Ebert; H. Exner

    2007-01-01

    Purpose – The purpose of the paper is the elucidation of certain mechanisms of laser material processing in general and laser micro sintering in particular. One major intention is to emphasize the synergism of the various effects of q-switched laser pulses upon metal and ceramic powder material and to point out the non-equilibrium character of reaction steps. Design\\/methodology\\/approach – Recent

  10. Sintered titanium carbide hard alloys

    Microsoft Academic Search

    G. V. Samsonov; N. N. Sergeev; G. T. Dzodziev; V. K. Vitryanyuk; L. V. Latyaeva

    1971-01-01

    1.A study was made of the preparation of titanium carbide hard alloys with a nickel binder. It is shown that satisfactory mechanical properties (bend strength 107–115 kg\\/mm2, hardness 90–90.5 HRA) are exhibited by 80% TiC-20% Ni alloys produced from fine-milled mixtures by sintering in a vacuum of 5·10-3 mm Hg at a temperature of 1300‡C and an isothermal holding time

  11. Non-Sintered Nickel Electrode

    DOEpatents

    Bernard, Patrick (Massy, FR); Dennig, Corinne (Asnieres sur Seine, FR); Cocciantelli, Jean-Michel (Bordeaux, FR); Alcorta, Jose (Bordeaux, FR); Coco, Isabelle (Dax, FR)

    2002-01-01

    A non-sintered nickel electrode contains a conductive support and a paste comprising an electrochemically active material containing nickel hydroxide and a binder which is a mixture of an elastomer and a crystalline polymer. The proportion of the elastomer is in the range 25% to 60% by weight of the binder and the proportion of the crystalline polymer is in the range 40% to 75% by weight of the binder.

  12. Fast Sintering of Nanocrystalline Copper

    Microsoft Academic Search

    Alessandro Fais; Matteo Leoni; Paolo Scardi

    2011-01-01

    The behavior of nanocrystalline (nc) copper specimens obtained by high energy ball milling (HEBM) and electromagnetic field-assisted\\u000a sintering under stress and mechanical compression is explored. High yield stress values combined with plastic behavior are\\u000a observed. The basic densification mechanisms involved in the production process and the peculiar action on the dislocation\\u000a network are discussed.

  13. Sintering kinetics of large pores

    Microsoft Academic Search

    J. Pan; H. N. Ch’ng; A. C. F. Cocks

    2005-01-01

    The sintering kinetics of large pores in a dense polycrystalline solid is studied using computer simulation. Coupled grain-boundary diffusion, surface diffusion and grain-boundary migration are assumed as the underlying mechanisms for the microstructural evolution. A numerical method developed by Ch’ng and Pan [Ch’ng, H.N., Pan, J., 2004. Cubic spline elements for modelling microstructural evolution of materials controlled by solid state

  14. Influence of manganese on sintering processes in the Ti-Fe system. 1. Volume changes in sintering of Ti-Fe-Mn compacts

    SciTech Connect

    Kivalo, L.I.; Skorokhod, V.V.

    1986-05-01

    An investigation was made of the influence of manganese on the sintering processes in the titanium-iron system in the area of temperatures of existence of the first ternary eutectic point. Powders of titanium obtained by hydride-calcium reduction, ferromanganese, and types PZh4M2 and V3 iron were used. A figure presents data on the character of the volume changes in sintering of compacts of mixtures of titanium and iron powders with and without manganese. The x-ray analysis was made on a DRON-0.5 instrument. The profiles of intensities of the x-ray lines of Ti(Fe, Mn) phase present in specimens of mixture II are shown. With an increase in sintering temperature the line, which is diffuse at 1050 degrees C, gradually narrows, and at 1250 degrees C a doublet appears. At the time, the lattice parameter changes from 0.2976 for unalloyed TiFe to 0.2991 nm for Ti(Fe, Mn) obtained at 1250 degrees C. To obtain Ti(Fe, Mn) compounds of the required composition, it is necessary to take into account the amount of evaporated manganese.

  15. Prospecting For Magnetite Ore Deposits With A Innovative Sensor's of Unique Fundamentally New Magnetometer.

    NASA Astrophysics Data System (ADS)

    Emelianenko, T. I.; Tachaytdinov, R. S.; Sarichev, V. F.; Kotov, B. V.; Susoeva, G. N.

    After careful study of principles and abilities of all existing magnetmeters of all three revolutions in magnetic prospecting we have come to the conclusion that they cannot solve local guestions of the magnetic prospecting or determine centre coordinates of magnetite ore body before drilling Electromagnetism lows and achievents magnetprospectings and radioelectronics of all 20th century serve as a theoretical base of the "locator". While creating this cardinally new magnetmeter , we borrowed different things from radio-prospectors, magnetprospectors, wireless operators and combined all of them while creating the "locators''. The "locators' construction is bas ed on the "magnetic intensification" principle ,owing to which this "locators" are characterised by hight sensitiveness and ability to determine centers of even little commercial magnetite ore deposits with relatively weak magnetic anomalies. The main advantage of the "locators" over existing ones is that it can solve local questions determine centre coordinates. A remarkably simple locator construction determine direction of the on-surface measurings towards the ore body centre and gives approximate prognosis resourses before/withour/ drilling. The "locators" were worked out for the first time in history , they have 2 licences. The fundamental design and drawbacks of the existing magnetometers have been inherited from the original magnetometre dating back two or three hundred years. The developers of the existing magnetometres have all gone along the same well- beaten track of replacing the primitive sensor in the form of a piece of ore hung on a string at first by an arrow sensor and later by magnetically oriented protons and quanta, with amplification of the sensors' OUTPUT signal. Furthermore, all the existing magnetometres are imperfect in that they, lacking the directivity of the ground-level magnetic measurements, only record the overall magnetic vector field generated by all the ore bodies around the measurement point. The result is often misleading as an intense magnetic anomaly may be registered in a place where is no ore, and vice versa. Such false anomalies and maps may serve as the only guide in iron ore prospecting. The reserves' forecast based on such magnetic maps are also false as they may yield figures exceeding the actual reserves by tens or even hundreds of times. The existing magnetometres are often insufficiently sensitive and incapable of detecting small commercial processable ore bodies with a weak magnetic anomaly (less than 0.1% of the Earth's field). As regards new large iron ore deposits with strong anomalies, the probabilities of encountering them nowadays are becoming increasingly smaller. Confidence in the good performance and the advantages of the new magnetometres patented by the Magnitogorsk Iron and Steel Works is based on the following considerations: The anomalies' magnetic field is several times stronger than the magnetic field of the Earth; To cite two historical instances, the Sokolovskoye ore deposit in Kazakhstan was discovered in 1949 not by prospectors but by a civil aviation pilot, M.Surgutanov, using an ordinary airplane compass. The Kursk Magnetic Anomaly was discovered in 1778 by Professor I.Inozemtsev using a piece of ore hung on a string. The magnetometres patented by the MMK team, are based on the electromagnetism laws of Ampere, Ohm, Weber, Maxwell and Tesla. The history of magnetic prospecting can be divided into three periods, each of them preceded by a revolution of sorts. The first one occurred in 1910 when the German scientist Schmidt developed an optic mechanical magnetometre which came to be known in Russia as M-2 or "Fanzelau". The second revolution came about in 1936 with the invention by the Russian scientist A.Logachov of an AM-9L aeromagnetometre. The third revolution happened in 1953 when Pickard in the Unuted States (and Tsyrell in 1957 in the Soviet Union) invented a proton and quantum magnetometre. But, having examined the fundam

  16. 36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ...

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

    36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ORE BOAT. BY LATE WINTER, THE ORE STORAGE YARD SEEN AT LEFT WILL BE DEPLETED. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  17. Spark plasma sintering on nanometer scale WC–Co powder

    Microsoft Academic Search

    Cheng-Chang Jia; Hua Tang; Xue-Zhen Mei; Fa-Zhang Yin; Xuan-Hui Qu

    2005-01-01

    Nanometer scale WC–11Co powder was sintered by spark plasma sintering (SPS) process in order to improve the properties of the cemented carbides. Properties such as density and hardness were measured. The microstructures of sintered WC–11Co cemented carbides were observed. The grain size of WC in alloys was also obtained. The results showed that spark plasma sintering could lower the sintering

  18. Sintering behaviour of cobalt ferrite ceramic

    Microsoft Academic Search

    A. Rafferty; T. Prescott; D. Brabazon

    2008-01-01

    Pure cobalt ferrite ceramic powder was prepared using standard solid-state ceramic processing. Uniaxially pressed pure cobalt ferrite discs, sintered under isothermal ramp rate and single dwell time conditions, yielded a maximum theoretical density (%Dth) of <90%. Discs made from finer particle size powder yielded a %Dth of 91.5%. Based on dilatometry analysis, a sintering profile comprising non-isothermal sintering, and two-step

  19. Numerical Analysis of the Effect of Reduction Gas Composition and Temperature on the Quality of Sponge Iron Product

    Microsoft Academic Search

    Bayu Alamsari; Shuichi Torii; Yazid Bindar; Azis Trianto

    2010-01-01

    Reduction zone of iron ore reactor have been simulated. This is a part of counter current gas-solid reactor for producing sponge iron. The aim of this research is to study the effect of reduction gas composition and temperature on quality and product capacity of sponge iron products through mathematical modeling arrangement and simulation. Simultaneous mass and energy balances along the

  20. 8. EAST ELEVATION OF SKIDOO MILL AND UPPER ORE BIN, ...

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

    8. EAST ELEVATION OF SKIDOO MILL AND UPPER ORE BIN, LOOKING WEST FROM ACCESS ROAD. THE ROADWAY ON THIS LEVEL (CENTER) WAS USED FOR UNLOADING ORE BROUGHT ON BURROWS INTO THE ORE BIN AT THE TOP LEVEL OF THE MILL. THE ORE BIN IN THE UPPER LEFT WAS ADDED LATER WHEN ORE WAS BROUGHT TO THE MILL BY TRUCKS. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

  1. Project StORe: Social Science report 

    E-print Network

    Burton, Guy

    There was widespread support across the social science research community regarding the aims of the StORe Project Nearly half of social science respondents claimed that both source-to-output and out-put-to source repositories ...

  2. Open Scholarship 2006 StORe poster 

    E-print Network

    Pryor, Graham

    2006-01-01

    StORe is a project within the JISC digital repositories programme. It has a declared mission to enhance the value of academic research output by enabling direct interaction between source and output repositories

  3. Project StORe: Biosciences report 

    E-print Network

    Biegon, Dagmar

    2006-09-15

    This report was written as part of the first phase of the national higher education research project StORe (Source-to-Output Repositories). The project included a large scale analysis of repository user behaviour, with ...

  4. A comparative study of ZnS powders sintering by Hot Uniaxial Pressing (HUP) and Spark Plasma Sintering (SPS)

    Microsoft Academic Search

    C. Chlique; G. Delaizir; O. Merdrignac-Conanec; C. Roucau; M. Dollé; P. Rozier; V. Bouquet; X. H. Zhang

    2011-01-01

    The sintering of two different polycrystalline zinc sulphide powders has been investigated by two different techniques. Conventional sintering technique (Hot Uniaxial Pressing, HUP) and the Spark Plasma Sintering (SPS) also known as electric field-assisted sintering technique (FAST) have been compared in terms of sintering parameters (temperature, pressure) and optical properties of the prepared ZnS ceramics. This study demonstrates the potentiality

  5. A REAL-TIME COAL CONTENT/ORE GRADE (C2OC) SENSOR

    SciTech Connect

    Rand Swanson

    2005-04-01

    This is the final report of a three year DOE funded project titled ''A real-time coal content/ore grade (C{sub 2}OG) sensor''. The sensor, which is based on hyperspectral imaging technology, was designed to give a machine vision assay of ore or coal. Sensors were designed and built at Resonon, Inc., and then deployed at the Stillwater Mining Company core room in southcentral Montana for analyzing platinum/palladium ore and at the Montana Tech Spectroscopy Lab for analyzing coal and other materials. The Stillwater sensor imaged 91' of core and analyzed this data for surface sulfides which are considered to be pathfinder minerals for platinum/palladium at this mine. Our results indicate that the sensor could deliver a relative ore grade provided tool markings and iron oxidation were kept to a minimum. Coal, talc, and titanium sponge samples were also imaged and analyzed for content and grade with promising results. This research has led directly to a DOE SBIR Phase II award for Resonon to develop a down-hole imaging spectrometer based on the same imaging technology used in the Stillwater core room C{sub 2}OG sensor. The Stillwater Mining Company has estimated that this type of imaging system could lead to a 10% reduction in waste rock from their mine and provide a $650,000 benefit per year. The proposed system may also lead to an additional 10% of ore tonnage, which would provide a total economic benefit of more than $3.1 million per year. If this benefit could be realized on other metal ores for which the proposed technology is suitable, the possible economic benefits to U.S. mines is over $70 million per year. In addition to these currently lost economic benefits, there are also major energy losses from mining waste rock and environmental impacts from mining, processing, and disposing of waste rock.

  6. New silver contact pastes from high pressure sintering to low pressure sintering

    Microsoft Academic Search

    W. Schmitt; W. C. Heraeus

    2010-01-01

    Heraeus has developed a novel concept for silver sinter pastes. The new concept uses micro scale silver particles combined with sinter additives. The novel pastes have high sinter activity and a can be used in pressure free or less pressure bonding processes. The physical properties like shear strength at temperature above 200°C, electrical and thermal conductivity are outstanding compared to

  7. Friction Forces in O-ring Sealing

    Microsoft Academic Search

    In the present study the focus was on developing a relationship as practical and convenient option for computing the friction force in O-ring sealing elements as used in the hydraulic and pneumatic equipments. For low-pressure applications, the developed relationship was applied for a different number of O-ring diameters, by investigating the obtained results, a good agreement has been observed for

  8. Biomining: metal recovery from ores with microorganisms.

    PubMed

    Schippers, Axel; Hedrich, Sabrina; Vasters, Jürgen; Drobe, Malte; Sand, Wolfgang; Willscher, Sabine

    2014-01-01

    Biomining is an increasingly applied biotechnological procedure for processing of ores in the mining industry (biohydrometallurgy). Nowadays the production of copper from low-grade ores is the most important industrial application and a significant part of world copper production already originates from heap or dump/stockpile bioleaching. Conceptual differences exist between the industrial processes of bioleaching and biooxidation. Bioleaching is a conversion of an insoluble valuable metal into a soluble form by means of microorganisms. In biooxidation, on the other hand, gold is predominantly unlocked from refractory ores in large-scale stirred-tank biooxidation arrangements for further processing steps. In addition to copper and gold production, biomining is also used to produce cobalt, nickel, zinc, and uranium. Up to now, biomining has merely been used as a procedure in the processing of sulfide ores and uranium ore, but laboratory and pilot procedures already exist for the processing of silicate and oxide ores (e.g., laterites), for leaching of processing residues or mine waste dumps (mine tailings), as well as for the extraction of metals from industrial residues and waste (recycling). This chapter estimates the world production of copper, gold, and other metals by means of biomining and chemical leaching (bio-/hydrometallurgy) compared with metal production by pyrometallurgical procedures, and describes new developments in biomining. In addition, an overview is given about metal sulfide oxidizing microorganisms, fundamentals of biomining including bioleaching mechanisms and interface processes, as well as anaerobic bioleaching and bioleaching with heterotrophic microorganisms. PMID:23793914

  9. Antimony ore in the Fairbanks district, Alaska

    USGS Publications Warehouse

    Killeen, Pemberton Lewis; Mertie, John B., Jr.

    1951-01-01

    Antimony-bearing ores in the Fairbanks district, Alaska, are found principally in two areas, the extremities of which are at points 10 miles west and 23 miles northeast of Fairbanks; and one of two minor areas lies along this same trend 30 miles farther to the northeast. These areas are probably only local manifestations of mineralization that affected a much broader area and formed antimony-bearing deposits in neighboring districts, the closest of which is 50 miles away. The ores were exposed largely as a result of lode gold mining, but at two periods in the past, high prices for antimony ore warranted an independent production and about 2500 tons of stibnite ore was shipped. The sulfide deposits occupy the same fractures along which a gold-quartz mineralization of greater economic importance occurred; and both are probably genetically related to igneous rocks which intrude the schistose country rock. The sulfide is in part contemporaneous with some late-stage quartz in which it occurs as disseminated crystals; and in part the latest filling in the mineralized zones where it forms kidney-shaped masses of essentially solid sulfide. One extremely long mass must have contained nearly 100 tons of ore, but the average of the larger kidneys is closer to several tons. Much of the ore is stibnite, with quartz as a minor impurity, and assays show the tenor to vary from 40 to 65 percent antimony. Sulphantimonites are less abundant but likewise occur as disseminated crystals and as kidney-shaped bodies. Antimony oxides appear on the weathered surface and along fractures within the sulfide ore. Deposits containing either stibnite or sulphantimonite are known at more than 50 localities, but only eighteen have produced ore and the bulk of this came from the mines. The geology of the deposit, and the nature, extent, and period of the workings are covered in the detailed descriptions of individual occurrences. Several geologic and economic factors, which greatly affect prospecting and mining for stibnite ore in the area, are outlined. The principal available ore and reserves are considered to be ores earlier mined but never shipped, ore minable from near-surface deposits, and ores recoverable as a by-product of future gold mining. The outlook for stibnite production in the district is very uncertain. Apparently the greater portion of stibnite ore has already been recovered and present operations will strip the two principal areas of the district. This conclusion is based on the scanty discoveries since the last war and the fact that the areas are so pock-marked with prospects that there is little likelihood that any other large near-surface bodies remain to be discovered. Future prospecting would essentially be limited to attempts to seek the continuation of lodes previously having high yields of stibnite.

  10. Method of sintering materials with microwave radiation

    DOEpatents

    Kimrey, Jr., Harold D. (Knoxville, TN); Holcombe, Jr., Cressie E. (Farragut, TN); Dykes, Norman L. (Oak Ridge, TN)

    1994-01-01

    A method of sintering ceramic materials following: A compacted article comprising inorganic particles coated with carbon is provided, the carbon providing improved microwave coupling. The compacted article is then heated by microwave radiation to a temperature and for a period of time sufficient to sinter the compacted article.

  11. DESULFURIZATION OF STEEL MILL SINTER PLANT GASES

    EPA Science Inventory

    The report gives results of an evaluation of the technical and economic feasibility of using limestone scrubbing technology to control sinter plant emissions. Data from Soviet and Japanese sinter plants employing limestone scrubbing technology were used to develop a realistic des...

  12. Advances in sintering of hard metals

    Microsoft Academic Search

    A. Upadhyaya; D. Sarathy; G. Wagner

    2001-01-01

    Among the various advances in the processing of cemented carbides, this study emphasizes on the strategies to reduce the sintering time and improving the properties. It has been shown that the cycle time for consolidating metal cutting grades can be reduced by as much as 70% by employing a fast dewaxing-rapid sintering approach. For mining and metal-forming grade hard metals,

  13. Effect of Process Parameter on Barium Titanate Stannate (BTS) Materials Sintered at Low Sintering

    NASA Astrophysics Data System (ADS)

    Shukla, Alok; Bajpai, P. K.

    2011-11-01

    Ba(Ti1-xSnx)O3 solid solutions with (x = 0.15, 0.20, 0.30 and 0.40) are synthesized using conventional solid state reaction method. Formation of solid solutions in the range 0 ? x ?0.40 is confirmed using X-ray diffraction technique. Single phase solid solutions with homogeneous grain distribution are observed at relatively low sintering by controlling process parameters viz. sintering time. Composition at optimized temperature (1150 °C) sintered by varying the sintering time, stabilize in cubic perovskite phase. The % experimental density increase with increasing the time of sintering instead of increasing sintering temperature. The lattice parameter increases by increasing the tin composition in the material. This demonstrates that process parameter optimization can lead to single phase at relatively lower sintering-a major advantage for the materials used as capacitor element in MLCC.

  14. Manufacture of high-density ceramic sinters

    NASA Technical Reports Server (NTRS)

    Hibata, Y.

    1986-01-01

    High density ceramic sinters are manufactured by coating premolded or presintered porous ceramics with a sealing material of high SiO2 porous glass or nitride glass and then sintering by hot isostatic pressing. The ceramics have excellent abrasion and corrosion resistances. Thus LC-10 (Si3N2 powder) and Y2O3-Al2O3 type sintering were mixed and molded to give a premolded porous ceramic (porosity 37%, relative bulk density 63%). The ceramic was dipped in a slurry containing high SiO2 porous glass and an alcohol solution of cellulose acetate and dried. The coated ceramic was treated in a nitrogen atmosphere and then sintered by hot isostatic pressing to give a dense ceramic sinter.

  15. Exploring the engine of anthropogenic iron cycles

    PubMed Central

    Müller, Daniel B.; Wang, Tao; Duval, Benjamin; Graedel, T. E.

    2006-01-01

    Stocks of products in use are the pivotal engines that drive anthropogenic metal cycles: They support the lives of people by providing services to them; they are sources for future secondary resources (scrap); and demand for in-use stocks generates demand for metals. Despite their great importance and their impacts on other parts of the metal cycles and the environment, the study of in-use stocks has heretofore been widely neglected. Here we investigate anthropogenic and geogenic iron stocks in the United States (U.S.) by analyzing the iron cycle over the period 1900–2004. Our results show the following. (i) Over the last century, the U.S. iron stock in use increased to 3,200 Tg (million metric tons), which is the same order of magnitude as the remaining U.S. iron stock in identified ores. On a global scale, anthropogenic iron stocks are less significant compared with natural ores, but their relative importance is increasing. (ii) With a perfect recycling system, the U.S. could substitute scrap utilization for domestic mining. (iii) The per-capita in-use iron stock reached saturation at 11–12 metric tons in ?1980. This last finding, if applicable to other economies as well, could allow a significant improvement of long-term forecasting of steel demand and scrap availability in emerging market economies and therefore has major implications for resource sustainability, recycling technology, and industrial and governmental policy. PMID:17053079

  16. Machine vision system for ore sizing

    NASA Astrophysics Data System (ADS)

    Eichelberger, Christopher L.; Blair, Steven M.; Khorana, Brij M.

    1991-03-01

    A machine vision systelu has been developed to size and count ore as it passes down a conveyor belt. The imaging system consists of a line scan camera a zoom lens and a structured lighting arrangenient. The structured lighting produces a line of light which is projected onto the conveyor belt at an angle with respect to the caniera. When a piece of ore is present the line of light covering the piece is displaced out of the field of view of the camera. This method is used to overcome the poor contrast between the ore and the conveyor belt. Iniages are acquired using an iiaage processor which performs real-tiiae thresholding of the iraage before it is passed to a frame buffer. A coniputer progrant locates the ore pieces in the image and identifies the boundaries between those pieces which are touching. Chords corresponding to the approximate major and minor axes of each piece are calculated. Using these measurements the size distribution for a population of ore is determined. 1.

  17. Photochemical changes in cyanide speciation in drainage from a precious metal ore heap.

    PubMed

    Johnson, Craig A; Leinz, Reinhard W; Grimes, David J; Rye, Robert O

    2002-03-01

    In drainage from an inactive ore heap at a former gold mine, the speciation of cyanide and the concentrations of several metals were found to follow diurnal cycles. Concentrations of the hexacyanoferrate complex, iron, manganese, and ammonium were higher at night than during the day, whereas weak-acid-dissociable cyanide, silver, gold, copper, nitrite, and pH displayed the reverse behavior. The changes in cyanide speciation, iron, and trace metals can be explained by photodissociation of iron and cobalt cyanocomplexes as the solutions emerged from the heap into sunlight-exposed channels. At midday, environmentally significant concentrations of free cyanide were produced in a matter of minutes, causing trace copper, silver, and gold to be mobilized as cyanocomplexes from solids. Whether rapid photodissociation is a general phenomenon common to other sites will be important to determine in reaching a general understanding of the environmental risks posed by routine or accidental water discharges from precious metal mining facilities. PMID:11918005

  18. Photochemical changes in cyanide speciation in drainage from a precious metal ore heap

    USGS Publications Warehouse

    Johnson, C.A.; Leinz, R.W.; Grimes, D.J.; Rye, R.O.

    2002-01-01

    In drainage from an inactive ore heap at a former gold mine, the speciation of cyanide and the concentrations of several metals were found to follow diurnal cycles. Concentrations of the hexacyanoferrate complex, iron, manganese, and ammonium were higher at night than during the day, whereas weak-acid-dissociable cyanide, silver, gold, copper, nitrite, and pH displayed the reverse behavior. The changes in cyanide speciation, iron, and trace metals can be explained by photodissociation of iron and cobalt cyanocomplexes as the solutions emerged from the heap into sunlight-exposed channels. At midday, environmentally significant concentrations of free cyanide were produced in a matter of minutes, causing trace copper, silver, and gold to be mobilized as cyanocomplexes from solids. Whether rapid photodissociation is a general phenomenon common to other sites will be important to determine in reaching a general understanding of the environmental risks posed by routine or accidental water discharges from precious metal mining facilities.

  19. Nondestructive evaluation of sintered ceramics

    NASA Technical Reports Server (NTRS)

    Baaklini, George Y.; Klima, Stanley J.; Sanders, William A.

    1988-01-01

    Radiography and several acoustic and thermoacoustic microscopy techniques are investigated for application to structural ceramics for advanced heat engines. A comparison is made of the results obtained from the use of scanning acoustic microscopy (SAM), scanning laser acoustic microscopy (SLAM), and thermoacoustic microscopy (TAM). These techniques are evaluated on research samples of green and sintered monolithic silicon nitrides and silicon carbides in the form of modulus-of-rupture (MOR) bars containing deliberately introduced flaws. Strengths and limitations of the techniques are described, with the emphasis being on statistics of detectability of flaws that constitute potential fracture origins. Further, it is shown that radiographic evaluation and guidance helped develop uniform high-density Si3N4 MOR bars with improved four-point flexural strength (875, 544, and 462 MPa at room temperature, 1200 C, 1370 C, respectively) and reduced scatter in bend strength.

  20. Tribological properties of sintered polycrystalline and single crystal silicon carbide

    NASA Technical Reports Server (NTRS)

    Miyoshi, K.; Buckley, D. H.; Srinivasan, M.

    1982-01-01

    Tribological studies and X-ray photoelectron spectroscopy analyses were conducted with sintered polycrystalline and single crystal silicon carbide surfaces in sliding contact with iron at various temperatures to 1500 C in a vacuum of 30 nPa. The results indicate that there is a significant temperature influence on both the friction properties and the surface chemistry of silicon carbide. The main contaminants on the as received sintered polycrystalline silicon carbide surfaces are adsorbed carbon, oxygen, graphite, and silicon dioxide. The surface revealed a low coefficient of friction. This is due to the presence of the graphite on the surface. At temperatures of 400 to 600 C graphite and copious amount of silicon dioxide were observed on the polycrystalline silicon carbide surface in addition to silicon carbide. At 800 C, the amount of the silicon dioxide decreased rapidly and the silicon carbide type silicon and carbon peaks were at a maximum intensity in the XPS spectra. The coefficients of friction were high in the temperature range 400 to 800 C. Small amounts of carbon and oxygen contaminants were observed on the as received single crystal silicon carbide surface below 250 C. Silicon carbide type silicon and carbon peaks were seen on the silicon carbide in addition to very small amount of graphite and silicon dioxide at temperatures of 450 to 800 C.

  1. Evaluation of feasibility of static tests applied to Küre VMS ore deposits

    NASA Astrophysics Data System (ADS)

    Demirel, Cansu; Çelik Balci, Nurgül; ?eref Sönmez, M.

    2015-04-01

    Küre volcanogenic massive sulfide (VMS) ore deposits have been mined for its copper content for over centuries. However, there is no published data on AMD around Küre VMS ore deposits. This study investigates the sources of acid producing mechanisms in Küre, using field and laboratorial approaches. Geochemical static tests to predict AMD generation are widely applied to mining sites for assessing potential environmental consequences. However, there are well known limitations of these methods particularly resulting from assumptions used for calculations. To test the feasibility of the methods to predict potential of AMD generation of Küre (VMS) copper deposits, for the first time, acid production and neutralization potential of various mine wastes of Küre (VMS) copper deposits were determined. To test our static test results, in situ and laboratory geochemical data were also obtained from the groundwater discharges from Bakibaba underground mining tunnels. Feasibility study showed that, despite a few inconsistencies, static tests were suitable for predicting generation of AMD around Küre copper mining site and reflected well the site conditions. The current study revealed that pulp density, defined as solid/liquid ratio and used for static tests, is an important limiting factor to predict reliable data for AMD generation. In this study, we also determined surface waters affected by AMD are predicted to have a pH value between 3 and 5, with an average of pH 4. Excessive concentrations of manganese, copper, cobalt and sulfate are also noted with considerable amounts of iron and zinc, which can reach to toxic levels. Moreover, iron and zinc were found to be the controlling the fate of metals by precipitation and co-precipitation, due to their relatively depleted concentrations at redox shifting zones. Key words: Küre pyritic copper ore, Bakibaba mining tunnels, volcanogenic massive sulfide ore deposits, acid production potential, neutralization potential, feasibility, groundwater chemistry

  2. 4. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO ...

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

    4. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO EAST. - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

  3. 3. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO ...

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

    3. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO WEST. - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

  4. 1. VIEW TO SOUTH (RETAINING WALL OF ORE RECEIVING PLATFORM ...

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

    1. VIEW TO SOUTH (RETAINING WALL OF ORE RECEIVING PLATFORM TO LEFT). - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

  5. 2. VIEW TO NORTHEAST (ORE RECEIVING PLATFORM OUT OF VIEW ...

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

    2. VIEW TO NORTHEAST (ORE RECEIVING PLATFORM OUT OF VIEW TO RIGHT). - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

  6. CONTEXT VIEW ACROSS ORE YARD AT MODERN SELFUNLOADING BOOM IN ...

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

    CONTEXT VIEW ACROSS ORE YARD AT MODERN SELF-UNLOADING BOOM IN FRONT OF HULETTS. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  7. 4. From west side of boat slip; ore piles, unloaders, ...

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

    4. From west side of boat slip; ore piles, unloaders, blast furnaces, tube conveyors, ore conveyors, stock house, powerhouse. Looking north/northeast - Rouge Steel Company, 3001 Miller Road, Dearborn, Wayne County, MI

  8. CONTEXT VIEW ACROSS ORE YARD AT MODERN SELFUNLOADING SHIP UNLOADING ...

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

    CONTEXT VIEW ACROSS ORE YARD AT MODERN SELF-UNLOADING SHIP UNLOADING IN FRONT OF HULETTS. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  9. AERIAL OVERVIEW, LOOKING NORTH, WITH FORMER TCIUS STEEL ORE MINE ...

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

    AERIAL OVERVIEW, LOOKING NORTH, WITH FORMER TCI-US STEEL ORE MINE HEADQUARTERS (BOTTOM) AND SUPERINTENDENT'S AND FOREMAN HOUSING ALONG MINNESOTA AVENUE AT CREST OF RED MOUNTAIN (TOP LEFT). - Muscoda Red Ore Mining Community, Bessemer, Jefferson County, AL

  10. AMT survey in the Outokumpu ore Belt, Eastern Finland

    NASA Astrophysics Data System (ADS)

    Lahti, Ilkka; Kontinen, Asko; Aatos, Soile; Smirnov, Maxim

    2015-04-01

    The Outokumpu ore belt comprises Paleoroterozoic turbiditic deep-water sediments enclosing fault-bound ophiolitic slices composed dominantly of serpentinites derived from oceanic upper mantle peridotites. These together form the allochthonous Outokumpu suite that was emplaced onto the Karelian Craton margin during the early stages of the Svecofennian Orogeny. The area which has been over 100 years among the most important mining regions in Finland is still supporting active mining and exploration. The main prospectivity is for polymetallic (Cu-Co-Zn-Ni-Ag-Au) sulfide ores that are hosted by carbonate, calc-silicate and quartz rocks fringing serpentinite bodies embedded in extensive formations of electrically conductive iron sulfide and graphite-bearing black schists that are showing no geochemical vectors to the ores (e.g. Peltonen et al., 2008). The presence of conductive schists makes also electromagnetic exploration of the sulfide ores challenging. However, the detection of the black schists at depth would be useful in locating new environments with potential for the serpentinites and prospective Outokumpu rock assemblage. Audiomagnetotelluric (AMT) data has been recently collected to image subsurface conductivity structure of the belt. These data were acquired along five profiles transecting several key-features, including the Miihkali serpentinite, Archean Sotkuma gneiss window and the area SE from the Outokumpu mine. Altogether 91 sites were measured with the site spacing of 300 m - 2 km. AMT data (f = 1 - 10 000 Hz) were acquired during daytime whereas night-recordings enabled to obtain data at the frequency range of 0.01 - 10 000 Hz. Measurements were done using two Metronix 24bit ADU-07e broadband electromagnetic acquisition systems. Robust remote reference processing yielded mostly good data quality, particularly for data recorded during night-time. The survey area is favorable for 2-D modeling as it is characterized by thin, laterally extensive conductors indicated by airborne electromagnetic data and regional strike analysis of acquired impedance tensor data. Two-dimensional inversion was done jointly for TE, TM- and Tipper data using the inversion code by Rodi and Mackie (2001). Results are visualized as sounding curves, sections of electrical conductivity and induction vectors. Results show dipping and sub-horizontal conductors southeast of the Outokumpu town. One c. 1 km deep sub-horizontal conductor is verified by a drill hole located approximately 8 km from the town. Gently eastwards dipping conductor was detected in the Miihkali serpentinite area. Conductors are absent in the uppermost ~ 7 km below the Sotkuma gneisses, which consequently represent rather a uplifted fault block than a thrust sheet of the Archaean basement rocks, thus resolving an old debate concerning the crustal structure at Sotkuma. In addition to AMT, high resolution seismic and airborne ZTEM surveys have been recently carried out in the study area providing a good opportunity to compare results from different deep penetrating geophysical methods. References Peltonen, P., Kontinen, A., Huhma, H. and Kuronen, U. 2008. Outokumpu revisited: New mineral deposit model for the mantle peridotite-associated Cu-Co-Zn-Ni-Ag-Au sulphide deposits: Ore Geology Reviews, 33, no. 3-4, 559-617. Rodi, W. and Mackie, R. 2001. Nonlinear conjugate gradients algorithm for 2-D magnetotelluric inversion. Geophysics, 66, 174-187.

  11. Liquid phase sintering of silicon carbide

    DOEpatents

    Cutler, R.A.; Virkar, A.V.; Hurford, A.C.

    1989-05-09

    Liquid phase sintering is used to densify silicon carbide based ceramics using a compound comprising a rare earth oxide and aluminum oxide to form liquids at temperatures in excess of 1,600 C. The resulting sintered ceramic body has a density greater than 95% of its theoretical density and hardness in excess of 23 GPa. Boron and carbon are not needed to promote densification and silicon carbide powder with an average particle size of greater than one micron can be densified via the liquid phase process. The sintered ceramic bodies made by the present invention are fine grained and have secondary phases resulting from the liquid phase. 4 figs.

  12. Liquid-phase sintering of ceramics

    SciTech Connect

    Marion, J.E.; Hsueh, C.H.; Evans, A.G.

    1987-10-01

    Expressions for the sintering rate in liquid-phase sintering are derived for coupled-interface dissolution and liquid-phase diffusion. The analysis reveals the important role of stress gradients in the grain boundary phase and also shows that such gradients cannot be supplied by liquid-phase flow. Stress-supporting structure in the grain boundary phase is thus implied. The probable existence of such structure is revealed by diffuse dark-field scattering studies, using transmission electron microscopy, on partially sintered alumina/anorthite bodies.

  13. (Data in thousand metric tons, gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced

    E-print Network

    Torgersen, Christian

    and the Midwestern United States. Most ore consumption was related to steel production, directly in pig iron the highest level since 1981. Through the first 9 months of 2004, domestic steel production was 8% higher than that for the same period in 2003. Rising crude steel production in response to economic growth in North America

  14. (Data in thousand metric tons gross weight unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced domestically

    E-print Network

    Torgersen, Christian

    consumption was related to steel production, directly in pig iron manufacture and indirectly through upgrading in producer and consumer stock releases. Through September 2008, domestic steel production was 4% higher than Production and Use: Manganese ore containing 35% or more manganese was not produced domestically in 2008

  15. (Data in thousand metric tons, gross weight, unless otherwise specified) Domestic Production and Use: Manganese ore containing 35% or more manganese was not produced

    E-print Network

    Torgersen, Christian

    and the Midwestern United States. Most ore consumption was related to steel production, directly in pig iron for manganese ferroalloy demand usually falls in the range of 1% to 2% and is tied to steel production. Through the first 8 months of 2003, however, domestic steel production was the same as that for the same period

  16. TREATMENT OF HEXAVALENT CHROMIUM IN CHROMITE ORE PROCESSING SOLID WASTE USING A MIXED REDUCTANT SOLUTION OF FERROUS SULFATE AND SODIUM DITHIONITE

    EPA Science Inventory

    We developed a method for disseminating ferrous iron in the subsurface to enhance chemical reduction of hexavalent chromium (Cr(VI)) in a chromite ore processing solid waste derived from the production of ferrochrome alloy. The method utilizes ferrous sulfate (FeSO4) in combinati...

  17. Properties, microstructure and leaching of sintered sewage sludge ash

    Microsoft Academic Search

    C. R Cheeseman; C. J Sollars; S McEntee

    2003-01-01

    Sewage sludge incinerator ash has been compacted and fired at different temperatures to produce a range of sintered ceramic materials. The effects of sintering temperature and pressing pressure on density, water adsorption and shrinkage have been determined and the microstructure of material sintered at 1040°C for 1h characterised by X-ray diffraction (XRD) and scanning electron microscopy. Sintering produces potentially useful

  18. In situ measurement of the shrinkage during microwave sintering

    Microsoft Academic Search

    Sylvain Marinel; Etienne Savary

    2009-01-01

    The sintering of advanced ceramics requires very fast sintering method in order to avoid both grain growth and inter-diffusion. In this context, the microwave sintering is a very powerful method since it enables sintering in a very short time. However, up to now the trial error method is usually used to find the best parameters (incident power, resonance mode, etc.)

  19. Infiltration as post-processing of laser sintered metal parts

    Microsoft Academic Search

    J Dück; F Niebling; T Neeße; A Otto

    2004-01-01

    Laser sintering of metal parts is an additive production method applied in the field of rapid prototyping and rapid tooling. Direct metal laser sintering (DMLS) is a variant of the laser sintering processes. Metal powder is locally molten in this process and parts are built from layers. A fast laser sintering process, which is economically favourable, results in porous metal

  20. A comparative study of conventionally sintered and microwave sintered nickel zinc ferrite

    SciTech Connect

    Rani, Rekha [Electroceramics Research Lab, GVM Girls College, Sonepat-131001, India and School of Physics and Materials Science, Thapar University, Patiala-147004 (India); Juneja, J. K. [Department of Physics, Hindu College, Sonepat-131001 (India); Raina, K. K. [School of Physics and Materials Science, Thapar University, Patiala-147004 (India); Kotnala, R. K. [National Physical Laboratory, New Delhi -110012 (India); Prakash, Chandra, E-mail: cprakash2014@gmail.com [Solid State Physics Laboratory, Timarpur, Delhi - 110054 (India)

    2014-04-24

    For the present work, nickel zinc ferrite having compositional formula Ni{sub 0.8}Zn{sub 0.2}Fe{sub 2}O{sub 4} was synthesized by conventional solid state method and sintered in conventional and microwave furnaces. Pellets were sintered with very short soaking time of 10 min at 1150 °C in microwave furnace whereas 4 hrs of soaking time was selected for conventional sintering at 1200 °C. Phase formation was confirmed by X-ray diffraction analysis technique. Scanning electron micrographs were taken for microstructural study. Dielectric properties were studied as a function of temperature. To study magnetic behavior, M-H hysteresis loops were recorded for both samples. It is observed that microwave sintered sample could obtain comparable properties to the conventionally sintered one in lesser soaking time at lower sintering temperature.

  1. Process for recovering hydrocarbons from a diatomite-type ore

    SciTech Connect

    Davis, B.W.

    1983-02-15

    A process for recovering hydrocarbons from a diatomite-type ore which comprises contacting the diatomite ore with a C/sub 4/-C/sub 10/ alcohol and thereafter contacting the diatomite ore-alcohol mixture with an aqueous alkaline solution to separate a hydrocarbon-alcohol phase and an alkaline aqueous phase containing the stripped diatomite ore. Thereafter, the alcohol is distilled off from the hydrocarbon phase and recycled back into the initial process.

  2. Cognome e nome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ALGA 2 febbraio 2012 Compitino (2 ore)

    E-print Network

    Robbiano, Lorenzo

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ALGA 2 febbraio 2012­ Compitino (2 ore) Giustificare ogni affermazione Salvare il file CoCoA come

  3. Cognome e nome . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ALGA 14 novembre 2011 Compitino (2 ore)

    E-print Network

    Robbiano, Lorenzo

    . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ALGA 14 novembre 2011­ Compitino (2 ore) Giustificare ogni affermazione Salvare il file CoCoA come

  4. Placement Of O-Rings In Solid Rocket Booster

    NASA Technical Reports Server (NTRS)

    Wood, Charles

    1991-01-01

    Brief report proposes to modify placement of O-ring seals in joints of Solid Rocket Booster of Space Shuttle. Modified joint and seal essentially "inside-out" version of old joint and seal. O-rings placed between outer side of tang and clevis. Joint rotation pushes tang harder against O-rings, thereby making even tighter seal. Proposal derived from analysis of Space Shuttle Challenger disaster, attributed to failure of these O-ring seals.

  5. Effect of chemical composition and sintering conditions on the mechanical properties of sintered duplex stainless steels

    Microsoft Academic Search

    F. Martín; C. García; Y. Blanco

    2011-01-01

    Duplex stainless steels were obtained through powder metallurgy technology from austenitic AISI 316L and ferritic AISI 430L powders mixed in different amounts to obtain ratios of austenite\\/ferrite of 25\\/75, 50\\/50 and 75\\/25. Prepared powder mixes were compacted at 650 or 750MPa and sintered in N2–H2 atmosphere (95%-5%) at several sintering conditions and with three sintering cooling rates (furnace, gas and

  6. Preventing oxidation of iron sulfide minerals by polyethylene polyamines

    E-print Network

    Belzile, Nelson

    Preventing oxidation of iron sulfide minerals by polyethylene polyamines Yu-Wei Chen a,*, Yuerong provide an effective protective layer for sulfidic ores and significantly reduce the penetration an important catalyzing role in the oxidation of sulfides and acid mine generation. Polyethylene polyamines

  7. Geology and ore deposits of the Whitepine area, Tomichi mining district, Gunnison County, Colorado

    USGS Publications Warehouse

    Robinson, Charles Sherwood

    1956-01-01

    The Tomichi mining district is on the western slope of the Continental Divide near the southern end of the Sawatch Range in southeastern Gunnison County, Colorado. The most productive part of the Tomichi district was the Whitepine area. It is estimated that since the discovery of ore in 1879 the area has produced approximately $7,000,000, principally in lead and zinc, with lesser amounts of silver, copper, and gold. Geologically, the Whitepine area is a faulted syncline of Paleozoic rocks that was intruded by Tertiary igneous rocks. The oldest rock of the area is the Silver Plume granite of pre-Cambrian age. Deposited upon this successively were the Sawatch quartzite (Late Cambrian), Manitou dolomite (Early Ordovician), Harding quartzite (Middle Ordovician), Fremont dolomite (Lade Ordovician), Chaffee formation (Late Devonian), Leadville limestone (Late Mississippian), and Beldon shale (Late Pennsylvanian); a total thickness of about 1,450 feet. During the Laramide Revolution, the sedimentary rocks were folded into a broad northward-plunging syncline, faulted, and intruded by a series of igneous rocks. The igneous rocks, in order of relative age from oldest to youngest, are: a rhyolite stock, the Princeton quartz monzonite batholith, quartz monzonite or quartz latite porphyry dikes, and rhyolite or pitchstone porphyry dikes. The ore deposits of the Whitepine area may be classified into replacement deposits, vein deposits, and contact metamorphic deposits. The replacement deposits may be further subdivided into deposits along faults and bedded deposits. Of the types of deposits, the most productive have been the replacement deposits along faults. The major replacement deposits along faults are those of the Akron, Morning Star, and Victor mines. The ore deposits of these mines are in the foot wall of the Star faults in the Akron mine in the Manitou dolomite and in the Morning Star and Victor mines in the Leadville limestone. The chief bedded replacement deposits are those of the Erie, North Star, and Tenderfoot mines. In the Erie mine the ore deposits are in the Leadville limestone at, or just below, its contact with the Belden shale. In the North Star and Tenderfoot mines the ore bodies are in the Manitou dolomite along the crest of an anticline and the trough of a syncline, respectively. The vein deposits occur in the Silver Plume granite, Princeton quartz monzonite, and Paleozoic sedimentary rocks. The only vein of commercial importance was that of the Spar Copper mine, which is in the Silver Plume granite. Contact metamorphic minerals are found chiefly in the top of the Leadville limestone in the vicinity of the Erie mine, and in the limestone of the Belden shale. Magnetite is the only ore mineral and it was produced only from the Iron King mine. The replacement deposits consist, in general, of sphalerite, galena, pyrite, and chalcopyrite in a gangue of siliclfied limestone or dolomite, quartz, and calcite. The veins, for the most part, consist of pyrite and quartz with only minor amounts of galena, sphalerite, and chalcopyrite. In both types of deposits gold is believed to be associated with the pyrite and sphalerite and silver with the galena. Oxidized ore was the chief product of the early mining. This ore consists of calamine, cerussite, smithsonite, or anglesite, or a combination of these minerals, in a gangue of siliceous limestone or silicified limestone or dolomite. Oxidation did not extend, in most cases, for more than 150 feetbelow the surface. The ore deposits are believed to be genetically related to the Princeton quartz monzonite batholith. Ore-bearing solutions derived from the cooling of magma are believed to have migrated upwards along the pre-existing faults replacing favorable zones in the sedimentary rocks, or depositing quartz and ore minerals in open fissures in the igneous rocks.

  8. 17. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN ...

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

    17. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN BUILT IN 1911-1912, THIS WAS THE LARGEST ORE-UNLOADING DOCK ON THE GREAT LAKES. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  9. 29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE ...

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

    29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE M. HUMPHREY'S' CARGO OF 25,000. TONS OF ORE. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  10. 18. VIEW OF CRUDE ORE BINS FROM WEST. WEST CRUDE ...

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

    18. VIEW OF CRUDE ORE BINS FROM WEST. WEST CRUDE ORE BIN AND TRESTLE FROM TWO JOHNS TRAMLINE TO SOUTH, CRUDE ORE BIN IN FOREGROUND. MACHINE SHOP IN BACKGROUND. THE TRAM TO PORTLAND PASSED TO NORTH OF MACHINE SHOP. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  11. The Kiruna-type apatite-iron oxide system in central Sweden: geology and geochemical character

    NASA Astrophysics Data System (ADS)

    Högdahl, K.; Jonsson, E.; Nilsson, K.; Troll, V.

    2012-04-01

    The only apatite-iron oxide ores in the classic Palaeoproterozoic Bergslagen ore province, central Sweden, occur semi-continuously between Grängesberg and Idkerberget. Together, they represent the largest concentration of iron ore in this part of the Fennoscandian shield. Their mineralogy, geochemistry, geometry and host rock relations all suggest that they belong to the Kiruna-type class of deposits. The apatite-iron oxide ores in Bergslagen are hosted by 1.9 Ga variably altered, metavolcanic to meta-subvolcanic rocks ranging from rhyolitic to andesitic in composition. The region has been affected by three episodes of deformation (D1-3) and regional, greenschist to amphibolite facies metamorphism during the c. 1.9-1.8 Ga Svecokarelian orogeny. The Grängesberg deposits occur as narrow, moderately SE-dipping lenses that are concordant to S0 surfaces in the host rocks. Magnetic anomaly data indicate that they extend to a depth of at least 1.7 km. The lens geometry is mainly controlled by deformation during D2. Reverse, oblique, top-to-the NNW shear is evident in the footwall, and strain partitioning due to competence contrasts between the ore and altered host rocks resulted in flattening at competent ore lens crests, leading to asymmetrical folds with opposite vergence towards pinch areas where prolate strain prevailed. D1 is evident as a crenulated cleavage and D3 appears as gentle, large-scale open folds. Geochemical data on host rocks show a systematic enrichment in REE from the least to the most altered rocks. The ore-associated alteration assemblages and the apatite-iron oxide ore feature similar and elevated REE concentrations and profiles, suggesting a link between hydrothermal alteration and oxide ore formation. However, most ore magnetite has ?18O values between +0.3 and +3.4 ‰ (ranging from -0.4 to +4.9 ‰), consistent with fractionation of oxygen between magnetite and a felsic to intermediate magma at high temperatures (Jonsson et al. 2011). These values partly overlap with published data from the Kiruna ores, as well as with young Chilean deposits of a comparable type (Nyström et al. 2008). The lighter values can be explained by either (or a combination of both) later oxidation of the ores and a hydrothermal process of formation. A majority of moderately altered host rock ?18O (+5 to +10 ‰ (V-SMOW)), plot within the normal spectrum of igneous rocks. Based on isotope systematics, geochemistry and geological observations, we conclude that formation of these ores included a hydrothermal component, most likely directly related to an orthomagmatic process.

  12. Estimation of the activation energy of sintering in KNN ceramics using master sintering theory

    NASA Astrophysics Data System (ADS)

    Singh, Rajan; Patro, P. K.; Kulkarni, Ajit R.; Harendranath, C. S.

    2014-04-01

    The master sintering curve (MSC) of K0.5Na0.5NbO3 (KNN) ceramics was constructed using constant heating rate dilatometry data based on the combined stage sintering model. The linear shrinkage was recorded using three heating rates 5 °C, 7 °C and 11 °C/ min. The obtained results suggest that in MSC, the sintered density is a unique function of the integral of a temperature function over time and it is independent of the sintering history. The MSC theory can be applied to predict shrinkage and final density. Also, it can be used to design a reproducible process to fabricate ceramics with required density.

  13. Pressureless sintering of whiskered-toughened ceramic composites

    DOEpatents

    Tiegs, Terry N. (Lenoir City, TN)

    1994-01-01

    A pressureless sintering method is disclosed for use in the production of whisker-toughened ceramic composites wherein the sintered density of composites containing up to about 20 vol. % SiC whiskers is improved by reducing the average aspect ratio of the whiskers to from about 10 to about 20. Sintering aids further improve the density, permitting the production of composites containing 20 vol. % SiC with sintered densities of 94% or better of theoretical density by a pressureless sintering method.

  14. Pressureless sintering of whisker-toughened ceramic composites

    DOEpatents

    Tiegs, Terry N. (Lenoir City, TN)

    1993-01-01

    A pressureless sintering method is disclosed for use in the production of whisker-toughened ceramic composites wherein the sintered density of composites containing up to about 20 vol. % SiC whiskers is improved by reducing the average aspect ratio of the whiskers to from about 10 to about 20. Sintering aids further improve the density, permitting the production of composites containing 20 vol. % SiC with sintered densities of 94% or better of theoretical density by a pressureless sintering method.

  15. Bioleaching of zinc from low-grade complex sulfide ores in an airlift by isolated Leptospirillum ferrooxidans

    Microsoft Academic Search

    A. Giaveno; L. Lavalle; P. Chiacchiarini; E. Donati

    2007-01-01

    Bioleaching of low-grade complex sulfide ores from La Silvita and La Resbalosa (Patagonia Argentina) were carried out in a reverse flow airlift reactor by a native strain of Leptospirillum ferrooxidans (Lf-LS04). The reactor was filled with iron free 9K medium pH 1.8, with mineral particle size of –74 ?m, pulp density of 1% and a superficial air velocity of 0.01m s?

  16. Surface phenomena during the early stages of sintering in steels modified with Fe–Mn–Si–C master alloys

    SciTech Connect

    Oro, Raquel, E-mail: raqueld@chalmers.se [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE-41296 Gothenburg (Sweden); Campos, Mónica, E-mail: campos@ing.uc3m.es [Department of Materials Science and Engineering, IAAB, Universidad Carlos III de Madrid, Av. Universidad 30, 28911 Leganés, Madrid (Spain); Hryha, Eduard, E-mail: hryha@chalmers.se [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE-41296 Gothenburg (Sweden); Torralba, José Manuel, E-mail: torralba@ing.uc3m.es [Department of Materials Science and Engineering, IAAB, Universidad Carlos III de Madrid, Av. Universidad 30, 28911 Leganés, Madrid (Spain); IMDEA Materials Institute, C/Eric Kandel, 2, 28906 Getafe, Madrid (Spain); Nyborg, Lars, E-mail: lars.nyborg@chalmers.se [Department of Materials and Manufacturing Technology, Chalmers University of Technology, Rännvägen 2A, SE-41296 Gothenburg (Sweden)

    2013-12-15

    The characteristics of the metallic powder surface play a critical role in the development of strong bonds between particles during sintering, especially when introducing elements with a high affinity for oxygen. In this study, Mn and Si have been combined in a Fe–Mn–Si–C master alloy powder in order to reduce their chemical activity and prevent oxidation during the heating stage of the sintering process. However, when this master alloy powder is mixed with an iron base powder, differences in chemical activity between both components can lead to an oxygen transfer from the iron base powder to the surface of the master alloy particles. The present research is focused on studying the evolution of the master alloy particle surface during the early stages of sintering. Surface characterization by X-ray Photoelectron Spectroscopy (XPS) shows that the master alloy powder surface is mostly covered by a thin easily reducible iron oxide layer (? 1 nm). Mn–Si particulate oxides are found as inclusions in specific areas of the surface. Evolution of oxides during sintering was studied on green compacts containing iron powder, graphite and Fe–Mn–Si–C master alloy powder that were heat treated in vacuum (10{sup ?6} mbar) at different temperatures (from 400, 600, 800 to 1000 °C) and analyzed by means of XPS. Vacuum sintering provides the necessary conditions to remove manganese and silicon oxides from the powder surface in the range of temperatures between 600 °C and 1000 °C. When sintering in vacuum, since the gaseous products from reduction processes are continuously eliminated, oxidation of master alloy particles due to oxygen transfer through the atmosphere is minimized. - Highlights: • Mn and Si were introduced in sintered steels using a master alloy powder. • Surface of the master alloy is mainly covered by an easily reducible iron oxide. • Temperature ranges for oxidation/reduction are identified. • Vacuum conditions avoid oxygen transfer to oxidation sensitive elements. • Chemical activity of Mn and Si is lowered when combined in a form of master alloy.

  17. Sintered electrode for solid oxide fuel cells

    DOEpatents

    Ruka, Roswell J. (Pittsburgh, PA); Warner, Kathryn A. (Bryan, TX)

    1999-01-01

    A solid oxide fuel cell fuel electrode is produced by a sintering process. An underlayer is applied to the electrolyte of a solid oxide fuel cell in the form of a slurry, which is then dried. An overlayer is applied to the underlayer and then dried. The dried underlayer and overlayer are then sintered to form a fuel electrode. Both the underlayer and the overlayer comprise a combination of electrode metal such as nickel, and stabilized zirconia such as yttria-stabilized zirconia, with the overlayer comprising a greater percentage of electrode metal. The use of more stabilized zirconia in the underlayer provides good adhesion to the electrolyte of the fuel cell, while the use of more electrode metal in the overlayer provides good electrical conductivity. The sintered fuel electrode is less expensive to produce compared with conventional electrodes made by electrochemical vapor deposition processes. The sintered electrodes exhibit favorable performance characteristics, including good porosity, adhesion, electrical conductivity and freedom from degradation.

  18. High performance O-ring sealed joints

    Microsoft Academic Search

    R. Metcalfe; R. Wensel

    1994-01-01

    An integrated engineering approach to high performance sealing with O-rings is described. Sealing principles are explained, then used to illustrate the advantages of non-conventional geometries over handbook designs. The selection and qualification of optimal elastomer material for space shuttle applications is described, along with detection methods and rejection criteria for defects. The effects of lubrication, surface finish, squeeze, stretch and

  19. In brief: Project StORe 

    E-print Network

    Pryor, Graham

    Project StORe is one of twenty-five projects supported in the UK by the JISC (http://www.jisc.ac.uk) Digital Repositories Programme, which aims to bring together people and practices from across the domains of research, learning, information...

  20. Project StORe: Biosciences interviews 

    E-print Network

    Biegon, Dagmar

    2006-11-08

    This report was written as part of the first phase of the national higher education research project StORe (Source-to-Output Repositories). Data was acquired through a series of individual interviews which are presented here in full. The anonymous...

  1. Microbial leaching of lateritic nickel ore

    Microsoft Academic Search

    L. B. Sukla; V. V. Panchanadikar; R. N. Kar

    1993-01-01

    Lateritic nickel ore from the Sukinda Mines, Orissa, India, was leached using Thiobacillus ferrooxidans, Bacillus circulans, Bacillus licheniformis and Aspergillus niger at 5% (w\\/v) solid: liquid ratio for 5–20 days. Maximum leaching of Ni was achieved with B. circulans (85%) and Aspergillus niger (92%) after 20 days. Bacillus circulans showed significantly higher rate of leaching than the other organisms giving

  2. Production of uranium ore in capitalist countries

    Microsoft Academic Search

    N. I. Chesnokov; V. G. Ivanov

    1973-01-01

    The uranium deposits of the USA are concentrated in the sedimentary rocks of the Colorado plateau [2, 12]. The ore bodies are adapted to arkosic sandstones, conglomerates, limestones, and argillites. The reserves are distributed into a rather small number of large deposits and a large number of small deposits. Large deposits, each with reserves of from 50 to 100 thousand

  3. Sintering Behavior of Diboride Based Materials

    NASA Technical Reports Server (NTRS)

    Gasch, Matt; Gusman, Michael; Irby, Edward; Ellerby, Don; Beckman, Sarah; Johnson, Sylvia

    2003-01-01

    A brief history of diboride research, an overview of processing, and sintering studies are covered in this viewgraph presentation. UHTCs are a family of ceramic materials, including diborides of Hf and Zr, with extremely high melting temperatures. Spark Plasma Sintering (SPS) is a novel processing technique useful in consolidating difficult materials. The presentation also contains microphotographs of the microstructure of HfB2 and ZrB2 processed in different ways.

  4. SINTERABILITY STUDIES OF BeO COMPACTS

    Microsoft Academic Search

    Cooperstein

    1962-01-01

    Work was carried out to determine the optimum sintering conditions for ; cold-pressed BeO bodies from specific commercial lots of beryllia powder. The ; effects of 0.1 to 0.5 wt% additions of specific oxides on the sinterability of ; the beryllia powders were also studied. Results indicated that high-density ; bodies can be fabricated from pure sulfate-derived beryllia using a

  5. Effects of Heating Rate and Sintering Temperature on 316 l Stainless Steel Powders Sintered Under Multi-Physical Field Coupling

    Microsoft Academic Search

    Ankang Du; Yi Yang; Yi Qin; Gang Yang

    2012-01-01

    This paper presents an approach to fabricate micro components using multi-physical field sintering technique. In this study, 316 L stainless steel powders were sintered at different heating rates and sintering temperatures to produce cylindrical compacts with diameters of 1.0 mm, and heights of 1.0 mm. The effects of heating rates and sintering temperatures on sintering densification were studied. It shows that both heating

  6. Effect of sintering temperature on the thermoelectric properties of pulse discharge sintered (BiSb)Te alloy

    Microsoft Academic Search

    N. Keawprak; Z. M. Sun; H. Hashimoto; M. W. Barsoum

    2005-01-01

    P-type thermoelectric material (Bi0.24Sb0.76)2Te3 was sintered with pulse discharge sintering (PDS) process at temperatures of 345-495 ? C. The microstructures of sintered materials were found to be well aligned along the basal planes on the transverse direction, particularly when sintered at lower sintering temperatures. The carrier concentration was found to be higher in the transverse direction than in the longitudinal,

  7. 13. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN ...

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

    13. ORE DOCK, LOOKING EAST FROM HULETT NO. 1. WHEN BUILT IN 1911-1912, THIS WAS THE LARGEST ORE-UNLOADING DOCK ON THE GREAT LAKES. THE DOCK FEATURED FOUR HULETT UNLOADERS, EACH WITH A BUCKET CAPACITY OF 17 TONS; A 15-TON CAPACITY ORE STOCKING AND REHANDLING BRIDGE; AND A ONE-MILLION-TON CAPACITY ORE STORAGE YARD. THE WILLIAM-SEAVER-MORGAN COMPANY OF CLEVELAND BUILT THE DOCK EQUIPMENT. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  8. Sintered silicon nitrode recuperator fabrication

    NASA Technical Reports Server (NTRS)

    Gatti, A.; Chiu, W. S.; Mccreight, L. R.

    1980-01-01

    The preliminary design and a demonstration of the feasibility of fabricating submodules of an automotive Stirling engine recuperator for waste heat recovery at 370 C are described. Sinterable silicon nitride (Sialon) tubing and plates were fabricated by extrusion and hydrostatic pressing, respectively, suitable for demonstrating a potential method of constructing ceramic recuperator-type heat exchangers. These components were fired in nitrogen atmosphere to 1800 C without significant scale formation so that they can be used in the as-fired condition. A refractory glass composition (Al2O3 x 4.5 CaO.MgO x 11SiO2) was used to join and seal component parts by a brazing technique which formed strong recuperator submodules capable of withstanding repeated thermal cycling to 1370 C. The corrosion resistance of these materials to Na2SO4 + NaCl carbon mixtures was also assessed in atmospheres of air, hydrogen and CO2-N2-H2O mixtures at both 870 C and 1370 C for times to 1000 hours. No significant reaction was observed under any of these test conditions.

  9. Degradation Characteristics of O-rings on Highly Aged GIS

    NASA Astrophysics Data System (ADS)

    Minagawa, Tadao; Nagao, Eiichi; Tsuchie, Ei; Yonezawa, Hiroshi; Takayama, Daisuke; Yamakawa, Yutaka

    Owing to increasing number of highly aged GIS, the investigation of the remaining lifetimes of those systems are becoming more important. Because a lot of O-rings are used in GIS, the study of degradation mechanism and lifetime estimation method of O-ring is essential. In this paper, the information about O-ring degradation mechanism is described, and the statistical method for estimating the remaining lifetime of O-ring is proposed. The degradation of O-ring is mainly subject to chemical reactions triggered by oxygen. Because there are many factors influencing those chemical reactions, the dispersion of degradation rates of O-rings in GIS is very large. Consequently the statistical analysis is one of the effective techniques for lifetime estimation of O-rings in GIS.

  10. Process for extracting hydrocarbons from hydrocarbon bearing ores

    SciTech Connect

    Friedman, R.H.; Eakin, B.E.

    1986-02-18

    This patent describes a process for recovering hydrocarbons from a diatomite ore consisting of: reducing the size of the ore to less than about 5 mesh to form a reduced ore; combining the reduced ore with liquid to form ore pellets; treating the ore pellets to form extractable ore pellets; contacting a bed of the extractable pellets with extracting solvent in an extraction zone such that the relative velocity of the solvent to the extractable pellets is at least about one-half gallon per square foot per minute or more to thereby extract hydrocarbons from the extractable pellets and form spent pellets and a hydrocarbon rich solvent stream comprising extracting solvent and extracted hydrocarbons. The extracted hydrocarbons have an ash content of about less than 3 weight percent; and recovering extracting solvent from the spent pellets while retaining the spent pellets in pellet form without release of a significant amount of fines.

  11. Extraction process and apparatus for hydrocarbon containing ores

    SciTech Connect

    Friedman, R. H.; Eakin, B. E.

    1985-09-03

    There is provided a hydrocarbon extraction process and apparatus for removing hydrocarbons from a hydrocarbon containing ore such as a diatomite ore. The ore is preprocessed to the extent required to produce an extractable ore and subsequently mixed with a carrier to form an ore stream. The carrier may be a nonaqueous solvent and may further comprise a non-porous granular material such as sand. The ore stream is passed in substantially vertical countercurrent flow through a nonaqueous solvent to produce a product-solvent stream and a spent ore stream. The solvent is subsequently separated from the hydrocarbon stream, which may be further upgraded by removal of a heavy portion. This may be accomplished in the presence of a substantial amount of fines.

  12. DETAIL VIEW OF LOWER TRAM TERMINAL, SECONDARY ORE BIN, CRUSHER ...

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

    DETAIL VIEW OF LOWER TRAM TERMINAL, SECONDARY ORE BIN, CRUSHER FOUNDATION, AND BALL MILL FOUNDATIONS, LOOKING NORTH NORTHWEST. ORE FROM THE MINES WAS DUMPED FROM THE TRAM BUCKETS INTO THE PRIMARY ORE BIN UNDER THE TRAM TERMINAL. A SLIDING CONTROL DOOR INTRODUCED THE INTO THE JAW CRUSHER (FOUNDATIONS,CENTER). THE CRUSHED ORE WAS THEN CONVEYED INTO THE SECONDARY ORE BIN AT CENTER LEFT. A HOLE IN THE FLOOR OF THE ORE BIN PASSED ORE ONTO ANOTHER CONVEYOR THAT BROUGHT IT OUT TO THE BALL MILL(FOUNDATIONS,CENTER BOTTOM). THIS SYSTEM IS MOST LIKELY NOT THE ORIGINAL SET UP, PROBABLY INSTALLED IN THE MINE'S LAST OCCUPATION IN THE EARLY 1940s. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  13. Effects of composition and sintering time on liquid phase sintered Co-Cu samples in microgravity

    Microsoft Academic Search

    Yubin He; Saiyin Ye; J. Naser; J. Chiang; J. E. Smith

    2000-01-01

    Twelve Co-Cu powder compact samples with different liquid volume fractions were processed during microgravity liquid phase sintering on a suborbital sounding rocket and three Space Shuttle missions. The processing times ranged from 2.5 minutes to 66 minutes. The samples exhibited dimension stability after sintering. Microstructural evolutions such as densification, dihedral angle, contact per grain and grain growth rates, indicated a

  14. Sintering of the reaction products of combustion of alloys in nitrogen

    SciTech Connect

    Maksimov, Y.M.; Raskolenko, L.G.; Zepakova, O.K.; Ziatdinov, M.K.

    1986-05-01

    An investigation of the mechanism of compacting of Fe-V alloy with a sigma-phase structure, a low porosity composite material consisting of alpha-iron and a filler of delta-vanadium nitride, is made after the synthesis surge. Alloys containing 50 wt.% Fe were prepared by sintering in a vacuum furnace of powders of type VEL-1 vandium and special purity carbonyl iron. The mechanism of compacting was studied on specimens in hardened water. Metallographic investigations were made on MIM-7 and PMT-3 instruments and the phase analysis on a DRON-2 instrument. Rapid compacting in combustion of sigma-FeV in nitrogen is determined by combining of the solid-liquid drops formed in the combustion front and consisting of molten iron and vanadium nitrides.

  15. Iron chelators and iron toxicity

    Microsoft Academic Search

    Gary M. Brittenham

    2003-01-01

    Iron chelation may offer new approaches to the treatment and prevention of alcoholic liver disease. With chronic excess, either iron or alcohol alone may individually injure the liver and other organs. In combination, each exaggerates the adverse effects of the other. In alcoholic liver disease, both iron and alcohol contribute to the production of hepatic fibrosis through their effects on

  16. Effects of nickel on the sintering behavior of Fe-Ni compacts made from composite and elemental powders

    SciTech Connect

    Hwang, K.S. [National Taiwan Univ., Taipei (Taiwan, Province of China). Inst. of Materials Science and Engineering; Shiau, M.Y. [Team Young Advanced Ceramics Co. Ltd., Taoyuan (Taiwan, Province of China)

    1996-04-01

    Injection-molded Fe-Ni parts made from composite and elemental powders were prepared, and the effect of nickel on the sintering of iron compacts was investigated. Dilatometry analyses showed that the alpha-gamma phase transformation temperature of the Fe-Ni compact changed from a fixed 912 C for pure iron to a temperature range between 700 C and 912 C where two phases coexisted. The microstructure indicated that nickel impeded surface diffusion and slowed down the neck growth rate of iron powder in the early sintering stage. The dual phase and the small neck size at low temperatures suppressed the exaggerated grain growth, which usually occurs on carbonyl iron powders at 912 C. It was also observed that nickel impeded the grain growth of iron at high temperatures. Thus, by reducing the exaggerated grain growth during phase transformation, impeding the grain growth at high temperatures, and with high diffusion rates of iron in Ni-rich areas, enhanced densification was obtained for Fe-Ni systems, particularly for those systems made from composite powders. However, when coarse nickel powder was added, expansion was observed due to the presence of large pores around nickel powders. These pores were formed because of the particle rearrangement which was caused by the Kirkendall effect.

  17. Liquid phase sintering in microgravity

    NASA Astrophysics Data System (ADS)

    Smith, J.; Lundquist, C.; Riley, M.; Robinson, R.

    Liquid Phase Sintering (LPS) experiments have been conducted on four suborbital rockets, six Space Shuttle missions and two missions to the Mir Space Station by our research group. These missions began in 1989, spanning over 10 years. This paper will overview the many separate and interesting research and technical challenges faced in these missions and review the many published models developed to date by our group. The principle finding is that microgravity materials made using typical liquid phase sintering approaches are inferior to those made on earth. This results from pressing the green, presintered compact from their constituent powders, Fe and Co base materials with a Cu additive phase, producing composites that have solid volume fractions of 70-80%, with the balance either vacuum filled pores or entrapped gas. During LPS, the compact is processed above the melting point of the additive phase, producing a three-phase system. On earth, the entrapped gas is rapidly eliminated, and particle rearrangement is principally by buoyancy driven convection. In microgravity, this is not the case. In microgravity systems, all three phases exist concurrently, and the gas phase is not eliminated by buoyancy driven convection. Instead, the gas phase alters the free energy of the composite producing a variety of transport processes not typically seen in the earth based experiments, a positive result. Microgravity experiments slow down the typically fast acting rearrangement phase, permitting detailed study of the rapid processes taking place on earth in the first few seconds to minutes of LPS. Results from space processing have lead to a reconsideration of unit gravity models during the rearrangement stage. It has lead to a new model to explain the initiation of pore metamorphosis in LPS sample processed in microgravity, where pore breakup, coalescence and filling were found. Diffusion controlled grain growth in mutually soluble alloy phase systems, such as Co-Cu, was observed for the first time and a shrinking core model developed that successfully modeled this aspect of grain growth. In the absence of gravity, the grain coarsening model should follow the Lifshitz-Slyozov and Wagner (LSW) theory. Our extensive analysis of over 200 samples has shown that, contrary to expectation, there was an enhancement in particle coarsening with a decrease in the volume fraction of solid. The agglomerated microstructures exhibited a higher grain growth constant consistent with their higher 3D coordination number. Though buoyancy driven convection is eliminated, Brownian motion is not and becomes dominate in microgravity. This driving force leads to agglomeration and the need to use the Lifshitz-Slyozov Encounter Modified (LSEM) model to correctly model the results. Many papers on these phenomena h ve appeared in the literature and will be summarized anda presented along with a discussion of systems and subsystems needed to successfully conduct high temperature microgravity research on the fundamental mechanisms associated with LPS.

  18. Bioleaching of heavy metals from a low-grade mining ore using Aspergillus niger.

    PubMed

    Mulligan, Catherine N; Kamali, Mahtab; Gibbs, Bernard F

    2004-07-01

    The main concern of this study is to develop a feasible and economical technique to microbially recover metals from oxide low-grade ores. Owing to the significant quantities of metals that are embodied in low-grade ores and mining residues, these are potential viable sources of metals. In addition, they potentially endanger the environment, as the metals they contain may be released to the environment in hazardous form. Hence, mining industries are seeking an efficient, economic technique to handle these ores. Pyrometallurgical and hydrometallurgical techniques are either very expensive, energy intensive or have a negative impact on the environment. For these reasons, biohydrometallurgical techniques are coming into perspective. In this study, by employing Aspergillus niger, the feasibility of recovery of metals from a mining residue is shown. A. niger exhibits good potential in generating a variety of organic acids effective for metal solubilization. Organic acid effectiveness was enhanced when sulfuric acid was added to the medium. Different agricultural wastes such as potato peels were tested. In addition, different auxiliary processes were evaluated in order to either elevate the efficiency or reduce costs. Finally, maximum solubilization of 68%, 46% and 34% were achieved for copper, zinc and nickel, respectively. Also iron co-dissolution was minimized as only 7% removal occurred. PMID:15177728

  19. Determination of iron in nuclear grade zirconium oxide by x-ray fluorescence spectrometry using an internal intensity reference

    Microsoft Academic Search

    G. Radha Krishna; H. R. Ravindra; B. Gopalan; S. Syamsunder

    1995-01-01

    Iron forms an important constituent of zirconium alloys that are specially chosen for the fabrication of nuclear reactor core components. The concentration of iron in intermediate products is closely monitored during the manufacture of these alloys starting from the chemical processing of the ore zircon. In order to accomplish this, an x-ray fluorescence spectrometric technique using an internal ratio method

  20. Solid particle erosion behaviour of hardfacing deposits on cast iron—Influence of deposit microstructure and erodent particles

    Microsoft Academic Search

    S. Chatterjee; T. K. Pal

    2006-01-01

    Solid particle erosion (SPE) behaviour of different hardfacing electrodes deposited on gray cast iron (ASTM 2500) was studied using quartz sand and iron ore as erodent particles. Erosion test was carried out as per ASTM G76 test method. Considerable differences in erosion rates were found among different hardfacing electrodes at normal impact. Both volume fraction of carbides and type of

  1. Chromate Reduction in Highly Alkaline Groundwater by Zerovalent Iron: Implications for Its Use in a Permeable Reactive Barrier

    E-print Network

    Burke, Ian

    chromite ore processing residue (COPR). This study compares Cr(VI) removal from COPR leachate and chromate leachate. The reaction is first order with respect to both [Cr(VI)] and the iron surface area, but iron form in COPR leachate. Leachate from highly alkaline COPR contains Ca, Si, and Al that precipitate

  2. Nonisothermal viscous sintering of volcanic ash

    NASA Astrophysics Data System (ADS)

    Wadsworth, Fabian B.; Vasseur, Jérémie; Aulock, Felix W.; Hess, Kai-Uwe; Scheu, Bettina; Lavallée, Yan; Dingwell, Donald B.

    2014-12-01

    Volcanic ash is often deposited in a hot state. Volcanic ash containing glass, deposited above the glass transition interval, has the potential to sinter viscously both to itself (particle-particle) and to exposed surfaces. Here we constrain the kinetics of this process experimentally under nonisothermal conditions using standard glasses. In the absence of external load, this process is dominantly driven by surface relaxation. In such cases the sintering process is rate limited by the melt viscosity, the size of the particles and the melt-vapor interfacial tension. We propose a polydisperse continuum model that describes the transition from a packing of particles to a dense pore-free melt and evaluate its efficacy in describing the kinetics of volcanic viscous sintering. We apply our model to viscous sintering scenarios for cooling crystal-poor rhyolitic ash using the 2008 eruption of Chaitén volcano as a case example. We predict that moderate linear cooling rates of > 0.1°C min-1 can result in the common observation of incomplete sintering and the preservation of pore networks.

  3. Selecting Ore Pass-Finger Raise Configurations in Underground Mines

    NASA Astrophysics Data System (ADS)

    Esmaieli, Kamran; Hadjigeorgiou, John

    2011-05-01

    Material transfer in underground mines often relies on ore and waste pass systems. In mines where ore pass systems transcend multiple production levels, finger raises are used to funnel material into the system. Empirical evidence, from several mines, suggests that the use of finger raises often results in damage in the immediate vicinity of finger raise-ore pass junctions. Of particular concern is damage on the ore pass walls as a result of impact loads generated by material flowing through the fingers on to the ore pass walls. The severity of damage is directly related to the rock mass quality of the excavation walls, material properties of transiting ore and the ore pass-finger raise configuration. This paper examines the influence of different configurations aiming to develop strategies to minimize ore pass wall damage. To these purposes the Particle Flow Code was employed to undertake a series of numerical experiments. This involved dumping a batch of rock fragments, represented by a uniform distribution of disc-shaped particles, into a finger raise and allowed to flow into an ore pass. It has been clearly demonstrated that higher impact loads were generated when the angle of intersection between ore pass and finger raise was 140° to 145°. This configuration results in the most damage. The results of these numerical experiments were collaborated by observations at an underground mine in Canada.

  4. Speciation and characterization of arsenic in gold ores and cyanidation tailings using X-ray absorption spectroscopy

    USGS Publications Warehouse

    Paktunc, D.; Foster, A.; Heald, S.; Laflamme, G.

    2004-01-01

    The knowledge of mineralogy and molecular structure of As is needed to better understand the stability of As in wastes resulting from processing of gold ores. In this study, optical microscopy, scanning electron microscopy, electron microprobe, X-ray diffraction and X-ray absorption fine structure (XAFS) spectroscopy (including both XANES and EXAFS regimes) were employed to determine the mineralogical composition and local coordination environment of As in gold ores and process tailings from bench-scale tests designed to mimic a common plant practice. Arsenic-bearing minerals identified in the ores and tailings include iron (III) oxyhydroxides, scorodite (FeAsO4??2H2O), ferric arsenates, arseniosiderite (Ca2Fe3 (AsO4)3O2??3H2O), Ca-Fe arsenates, pharmacosiderite (KFe4 (AsO4)3(OH)4??6-7H2O), jarosite (K2Fe6(SO4)4 (OH)12) and arsenopyrite (FeAsS). Iron (III) oxyhydroxides contain variable levels of As from trace to about 22 wt% and Ca up to approximately 9 wt%. Finely ground ore and tailings samples were examined by bulk XAFS and selected mineral grains were analyzed by microfocused XAFS (micro-EXAFS) spectroscopy to reconcile the ambiguities of multiple As sources in the complex bulk EXAFS spectra. XANES spectra indicated that As occurs as As5+in all the samples. Micro-EXAFS spectra of individual iron (III) oxyhydroxide grains with varying As concentrations point to inner-sphere bidentate-binuclear arsenate complexes as the predominant form of As. There are indications for the presence of a second Fe shell corresponding to bidentate-mononuclear arrangement. Iron (III) oxyhydroxides with high As concentrations corresponding to maximum adsorption densities probably occur as nanoparticles. The discovery of Ca atoms around As in iron (III) oxyhydroxides at interatomic distances of 4.14-4.17 A?? and the coordination numbers suggest the formation of arseniosiderite-like nanoclusters by coprecipitation rather than simple adsorption of Ca onto iron (III) oxyhydroxides. Correlation of Ca with As in iron (III) oxyhydroxides as determined by electron microprobe analysis supports the coprecipitate origin for the presence of Ca in iron (III) oxyhydroxides. The samples containing higher abundances of ferric arsenates released higher As concentrations during the cyanidation tests. The presence of highly soluble ferric arsenates and Ca-Fe arsenates, and relatively unstable iron (III) oxyhydroxides with Fe/As molar ratios of less than 4 in the ore and process tailings suggests that not only the tailings in the impoundment will continue to release As, but also there is the potential for mobilization of As from the natural sources such as the unmined ore. ?? 2004 Elsevier Ltd.

  5. Amines compounds as inhibitors of PCDD/Fs de novo formation on sintering process fly ash.

    PubMed

    Xhrouet, Céline; Nadin, Caroline; De Pauw, Edwin

    2002-06-15

    The polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs) are highly toxic compounds produced by some natural processes and different human activities. Waste incineration as well as steel and iron industries, in particular, the sintering process, are among the principal sources of these pollutants. In this paper, two inhibitors, triethanolamine (TEA) and monoethanolamine (MEA) are tested relating to their abilityto prevent the de novo formation of PCDD/Fs on sinter plant fly ash. The amounts of both PCDDs and PCDFs, formed by thermal treatment of the fly ash, decrease when inhibitors are added. The best results, up to 90% reduction of the PCDD/ Fs formation, are obtained when MEA is mixed with the fly ash at the highest concentration tested (2 wt %). The addition of inhibitors modifies the PCDFs/PCDDs ratios and, under some experimental conditions, the PCDD/Fs homologue distributions, suggesting that more than one pathway for the de novo formation of PCDD/Fs exist. On the other hand, no modification in the PCDD/Fs isomer distributions is observed as a result of the addition of inhibitors, in accordance with the possible thermodynamic control of these distributions. The temperature tested, 325 and 400 degrees C, does not affect the inhibition activity; however, longer reaction times (4 h instead of 2 h) give better percentages of PCDD/Fs reduction. The results suggest that the two inhibitors and especially MEA can reduce the PCDD/Fs formation on sinter plant fly ash under various conditions of temperature and reaction time, making them suitable for use in the real process. Tests performed in parallel at a real sinter plant are in good agreement with the laboratory experiments and confirm that the use of inhibitors is an appropriate technique for the prevention of PCDD/Fs emissions from sintering processes. PMID:12099476

  6. Raman spectroscopy of efflorescent sulfate salts from Iron Mountain Mine Superfund Site, California.

    PubMed

    Sobron, Pablo; Alpers, Charles N

    2013-03-01

    The Iron Mountain Mine Superfund Site near Redding, California, is a massive sulfide ore deposit that was mined for iron, silver, gold, copper, zinc, and pyrite intermittently for nearly 100 years. As a result, both water and air reached the sulfide deposits deep within the mountain, producing acid mine drainage consisting of sulfuric acid and heavy metals from the ore. Particularly, the drainage water from the Richmond Mine at Iron Mountain is among the most acidic waters naturally found on Earth. The mineralogy at Iron Mountain can serve as a proxy for understanding sulfate formation on Mars. Selected sulfate efflorescent salts from Iron Mountain, formed from extremely acidic waters via drainage from sulfide mining, have been characterized by means of Raman spectroscopy. Gypsum, ferricopiapite, copiapite, melanterite, coquimbite, and voltaite are found within the samples. This work has implications for Mars mineralogical and geochemical investigations as well as for terrestrial environmental investigations related to acid mine drainage contamination. PMID:23464669

  7. Physical-chemical conditions of ore deposition

    USGS Publications Warehouse

    Barton, P.B., Jr.

    1981-01-01

    Ore deposits form under a wide range of physical and chemical conditions, but those precipitating from hot, aqueous fluids-i.e. the hydrothermal deposits-form generally below 700??C and at pressures of only 1 or 2 kbar or less. Natural aqueous fluids in rocks may extract metal and sulfur from a variety of rock types or may acquire them as a residual heritage from a crystallizing silicate magma. Ore-forming hydrothermal fluids never appear as hot springs (except in deep, submarine situations) because they boil, mix with surface waters, and cool, thereby losing their ore-bearing ability before reaching the surface. Mineral systems function as chemical buffers and indicators just as buffers and indicators function in a chemical laboratory. By reading the record written in the buffer/indicator assemblages of minerals one can reconstruct many aspects of the former chemical environment. By studying the record of changing conditions one may deduce information regarding the processes functioning to create the succession of chemical environments and the ore deposits they represent. The example of the OH vein at Creede, Colorado, shows a pH buffered by the K-feldspar + muscovite + quartz assemblage and the covariation of S2 and O2 buffered by the assemblage chlorite + pyrite + quartz. Boiling of the ore fluid led to its oxidation to hematite-bearing assemblages and simultaneously produced an intensely altered, sericitic capping over the vein in response to the condensation of vapors bearing acidic components. The solubility of metals as calculated from experimental and theoretical studies of mineral solubility appears too low by at least one or two powers of ten to explain the mineralization at Creede. In contrast to Creede where the mineral stabilities all point to a relatively consistent chemistry, the Mississippi Valley type deposits present a puzzle of conflicting chemical clues that are impossible to reconcile with any single equilibrium situation. Thus we must seriously consider metastable equilibria; those most likely involve redox disequilibrium among the sulfur species in solution and perhaps also involve organic compounds. ?? 1981.

  8. Violent volcanism, stagnant oceans and some inferences regarding petroleum, strata-bound ores and mass extinctions

    NASA Astrophysics Data System (ADS)

    Keith, M. L.

    1982-12-01

    Past changes from a well-mixed aerated ocean to a stratified stagnant ocean are indicated by decreasing ?13C of limestone (opposite to prior conclusions) as well as by increasing ?34S of marine sulfates. The proposed stagnant ocean model includes a warm CO 2-enriched atmosphere and a bathyal to abyssal marine system dominated by bacterial components in the food web and by consequent 'light' carbon in organic material and biogenic carbonates. Culminations of prolonged stagnant episodes correspond with marine faunal extinctions of Late Permian and Late Cretaceous time, and the protracted changes and correlations provide evidence against any hypothesis of mass extinction by sudden worldwide catastrophe, including the asteroid impact hypothesis. The Cretaceous stagnant ocean, taken as the prime example, is attributed to climatic warming triggered by volcanic CO 2 (greenhouse effect) and several feedbacks, including decreased Earth albedo and increased sinking of warm evaporite brines instead of aerated polar waters. Marine extinctions are attributed to upward expansion of the oxygen minimum zone and to catastrophic mixing of surface waters with poisonous sulfidic waters of the deeps. The stagnant ocean provided a counterbalance between deep reduction and shallow oxidation, conditions that favored maximal formation of black sulfidic shales, protopetroleum and sedimentary sulfide ores and shallow to mid-depth barite, phosphorite, iron ore, cherty iron formation, and sulfate-bearing red-beds. Trace elements concentrated in stagnant ocean sediments include chalcophile and Pt-group metals, negating claims that Ir provides a unique 'fingerprint' of meteorite impact and cosmic accretion.

  9. A circulation mud system used in long-distance ore pipeline transportation

    NASA Astrophysics Data System (ADS)

    Li, Youling; Wang, Hua

    2011-10-01

    The long-distance ore pipeline transportation is a new and high-tech industry, which is non-polluting, zero emissions, and in line with the strategy needs of national low-carbon economy and energy demand reduction. The long-distance ore transport needs multi-station pumping station transportation, however, the low concentration slurry that does not match the technological requirements, such as slurry head and so on. This paper designs a circulation mud system used in long-distance pipeline transportation, which solves the following issues: (1) the technical pool can't storage water during the period of cleaning mine, so can't meet the needs of non-suspension production; (2) slurry spot cool dry easy to bring serious environmental pollution; (3) the refined iron dug out from the process pool need transport to iron and steel industry, trucking transportation needs a huge costs. Experience has shown that the system effectively improve the production efficiency and propagate.

  10. Evolution of glass bubbles in VAD sintering process

    Microsoft Academic Search

    Alireza Hassani I; Nosratollah Granpayeh; Faramarz E. Seraji; Mohammad S. Zabihi

    2003-01-01

    Behavior of the bubbles in the fast and slow heating rate of the sintering process is simulated. In fast sintering, bubbles expand and can be joined together to create bigger bubbles. In slow heating rate, bubbles shrink slowly.

  11. New sintering process adjusts magnetic value of ferrite cores

    NASA Technical Reports Server (NTRS)

    Vinal, A. W.

    1964-01-01

    A two-phase sintering technique based on time and temperature permits reversible control of the coercive threshold of sintered ferrite cores. Threshold coercivity may be controlled over a substantial range of values by selective control of the cooling rate.

  12. ASTER, ALI and Hyperion sensors data for lithological mapping and ore minerals exploration.

    PubMed

    Beiranvand Pour, Amin; Hashim, Mazlan

    2014-01-01

    This paper provides a review of the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER), Advanced Land Imager (ALI), and Hyperion data and applications of the data as a tool for ore minerals exploration, lithological and structural mapping. Spectral information extraction from ASTER, ALI, and Hyperion data has great ability to assist geologists in all disciplines to map the distribution and detect the rock units exposed at the earth's surface. The near coincidence of Earth Observing System (EOS)/Terra and Earth Observing One (EO-1) platforms allows acquiring ASTER, ALI, and Hyperion imagery of the same ground areas, resulting accurate information for geological mapping applications especially in the reconnaissance stages of hydrothermal copper and gold exploration, chromite, magnetite, massive sulfide and uranium ore deposits, mineral components of soils and structural interpretation at both regional and district scales. Shortwave length infrared and thermal infrared bands of ASTER have sufficient spectral resolution to map fundamental absorptions of hydroxyl mineral groups and silica and carbonate minerals for regional mapping purposes. Ferric-iron bearing minerals can be discriminated using six unique wavelength bands of ALI spanning the visible and near infrared. Hyperion visible and near infrared bands (0.4 to 1.0 ?m) and shortwave infrared bands (0.9 to 2.5 ?m) allowed to produce image maps of iron oxide minerals, hydroxyl-bearing minerals, sulfates and carbonates in association with hydrothermal alteration assemblages, respectively. The techniques and achievements reviewed in the present paper can further introduce the efficacy of ASTER, ALI, and Hyperion data for future mineral and lithological mapping and exploration of the porphyry copper, epithermal gold, chromite, magnetite, massive sulfide and uranium ore deposits especially in arid and semi-arid territory. PMID:25674434

  13. Sintering of multi-metallic nanoparticles

    NASA Astrophysics Data System (ADS)

    Mukundan, Vineetha; Wanjala, Birgid; Loukrakpam, Rameshwori; Luo, Jin; Yin, Jun; Zhong, Chuan-Jian; Malis, Oana

    2012-02-01

    During the thermal treatment employed to activate the Pt-based nano catalysts used in fuel cell applications, the particles undergo structural transformations that affects their chemical performance. The mechanisms of coalescence and grain growth in bimetallic/trimetallic nanoparticles supported on planar silica on silicon are investigated using in-situ synchrotron based X-ray diffraction in the temperature regime 400-900C. The sintering process was found to be accompanied by lattice contraction and L10 chemical ordering. The mass transport involved in sintering is attributed to grain boundary diffusion and its corresponding activation energy is estimated from data analysis.

  14. Fusibility and sintering characteristics of ash

    SciTech Connect

    Ots, A. A., E-mail: aots@sti.ttu.ee [Tallinn University of Technology (Estonia)

    2012-03-15

    The temperature characteristics of ash fusibility are studied for a wide range of bituminous and brown coals, lignites, and shales with ratios R{sub B/A} of their alkaline and acid components between 0.03 and 4. Acritical value of R{sub B/A} is found at which the fusion temperatures are minimal. The sintering properties of the ashes are determined by measuring the force required to fracture a cylindrical sample. It is found that the strength of the samples increases sharply at certain temperatures. The alkali metal content of the ashes has a strong effect on their sintering characteristics.

  15. PROVA ORALE 1 MAGNISI RICCARDO 1 Febbraio 2012 ORE 15.00

    E-print Network

    Guidoni, Leonardo

    Febbraio 2012 ORE 15.00 56 TURELLA ENRICO MARIA 7 Febbraio 2012 ORE 15.00 57 VENTURI VANESSA 7 Febbraio 2012 ORE 15.00 #12;58 VENTURI THOMAS 7 Febbraio 2012 ORE 15.00 59 VENUTI ALESSANDRA 7 Febbraio 2012 ORE

  16. Agglomeration and defluidization in fluidized beds due to thermally induced sintering

    SciTech Connect

    Compo, P.; Pfeffer, R.; Tardos, G.I.

    1987-01-01

    The surfaces of fluidizable particles often soften at temperatures well below the material's bulk solid melting point. When particles come into contact at elevated temperatures, there is a tendency for material bridges to form resulting in an interparticle adhesive force. This phenomenon, known as sintering, is driven by the reduction of excess surface energy and for each material is dependent on factors such as particle size and morphology, the interparticle compression force and most importantly, temperature. High temperature fluidization of cohesive powders results in agglomeration, thereby increasing the effective diameter and changing the hydrodynamic properties of the particles. If interparticle forces become significantly greater than forces generated by particle motion, defluidization will occur. In industrial practice, agglomeration is usually undesirable and must be avoided, although there are cases where controlled agglomeration is useful as in fluid-bed coal gasification where the mineral matter agglomerates and is removed from the reactor. The experimental work reported here consists of dilatometry to determine the sintering behavior of a powder as a function of temperature and high temperature fluidization in a pilot size unit to measure the minimum fluidization velocity (defluidization limit) and the voidage at minimum fluidization in the cohesive temperature range of the material. A wide variety of particles have been studied ranging from pure substances including polymers, salts and glass beads to ores and cracking catalysts obtained from industrial reactors where problematic agglomeration at high temperature fluidization was encountered.

  17. Sintering characteristics of highly active UO2 powder

    SciTech Connect

    Saiki, Wataru; Onoue, Takeshi; Hasegawa, Shinichi [Mitsubishi Metal Company, Ibaraki (Japan)] [and others

    1995-12-31

    A highly active UO{sub 2} powder of 5 to 15m{sup 2}/g specific surface area can be obtained by a conversion process we have developed. This powder can be sintered to high density at a lower temperature than conventional powder; thus, the sintering temperature can be lowered in the manufacturing plant. In this study, sintering characteristics of the active powder, such as correlation of density with temperature, grain growth with sintering time, etc., have been evaluated.

  18. Room Temperature Aging Study of Butyl O-rings

    Microsoft Academic Search

    Mark Wilson

    2009-01-01

    During testing under the Enhanced Surveillance Campaign in 2001, preliminary data detected a previously unknown and potentially serious concern with recently procured butyl o-rings. All butyl o-rings molded from a proprietary formulation throughout the period circa 1999 through 2001 had less than a full cure. Tests showed that sealing force values for these suspect o-rings were much lower than expected

  19. Degradation Characteristics of O-rings on Highly Aged GIS

    Microsoft Academic Search

    Tadao Minagawa; Eiichi Nagao; Ei Tsuchie; Hiroshi Yonezawa; Daisuke Takayama; Yutaka Yamakawa

    2005-01-01

    Owing to increasing number of highly aged GIS, the investigation of the remaining lifetimes of those systems are becoming more important. Because a lot of O-rings are used in GIS, the study of degradation mechanism and lifetime estimation method of O-ring is essential. In this paper, the information about O-ring degradation mechanism is described, and the statistical method for estimating

  20. Microwave sintering of single plate-shaped articles

    DOEpatents

    Katz, Joel D. (Los Alamos, NM); Blake, Rodger D. (Tucson, AZ)

    1995-01-01

    Apparatus and method for high temperature sintering of plate-shaped articles of alumina, magnesia, silica, yttria, zirconia, and mixtures thereof using microwave radiation. An article is placed within a sintering structure located within a sintering container which is placed in a microwave cavity for heating. The rates at which heating and cooling take place is controlled.

  1. Microwave sintering of Yb:YAG transparent laser ceramics

    NASA Astrophysics Data System (ADS)

    Esposito, Laura; Piancastelli, Andreana; Bykov, Yury; Egorov, Sergei; Eremeev, Anatolii

    2013-02-01

    Reactive sintering of YAG based ceramics is generally performed under high vacuum in graphite-free furnaces in order to guarantee the elimination of pores and absence of any contamination. An alternative densification technique is the field assisted process such as spark plasma sintering and microwave sintering. Both of these methods are characterized by very fast heating rates, low sintering temperatures and short sintering times. The microwave sintering process is different from electric resistance heating since heat is generated in the bulk of the powder compact through electromagnetic radiation absorption and creates within its body uniform temperature distribution. Microwave sintering of laser ceramics is advantageously distinguished by the absence of any elements having high temperature such as electric heaters or dies which materials can contaminate the sintered parts. In addition, the inverse temperature distribution that exists within the body under volumetric microwave heating is favorable for elimination of porosity. Microwave sintering of Yb:YAG samples were tested and the obtained results are presented. The samples were sintered on a gyrotron-based system operating at a frequency of 24 GHz with microwave power up to 6 kW. Reactive sintering of YAG doped with 1.0, 5.0, and 9.8 at.% Yb2O3 was performed in different temperature-time regimes. The microstructure and the optical transmittance of the obtained samples were compared to those of samples obtained by conventional high vacuum sintering.

  2. Monte Carlo Simulation of Sintering on Multiprocessor Systems

    E-print Network

    Maguire Jr., Gerald Q.

    Monte Carlo Simulation of Sintering on Multiprocessor Systems Jens R. Lind Master of Science Thesis of Sintering on Multiprocessor Systems Author: Jens R. Lind Examiner: Vladimir Vlassov Master of Science Thesis great time and memory constraints. A metallurgy process called sintering, by which powders are formed

  3. Sealing Out-Of-Round Tubes With O-Rings

    NASA Technical Reports Server (NTRS)

    Shlichta, Paul J.

    1991-01-01

    Glass or ceramic tubes out-of-round sealed effectively by ordinary O-rings in caps of modified hydraulic fittings. In typical connection, O-ring squeezed between two surfaces having inward-opening slants of 5 degrees or 10 degrees. Slanted surfaces force ring inward, compressing it around tube. Connector metal fitting, tightened by hand around O-ring, seals O-ring against tube as much as 1/16 in. out of round. Modified connectors seal glass or ceramic tubes against gas or vacuum leakage in furnaces, vacuum systems, and tubes for glassblowing equipment.

  4. Experimenting With Ore: Creating the Taconite Process; flow chart of ...

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

    Experimenting With Ore: Creating the Taconite Process; flow chart of process - Mines Experiment Station, University of Minnesota, Twin Cities Campus, 56 East River Road, Minneapolis, Hennepin County, MN

  5. ‘Ultra’-low-temperature sintering of PZT: A synergy of nano-powder synthesis and addition of a sintering aid

    Microsoft Academic Search

    R. Mazumder; A. Sen

    2008-01-01

    It has been found that under certain conditions, PZT [Pb(Zr0.52Ti0.48)O3] can be sintered at a temperature as low as 715°C, whereas the conventional sintering temperature is around 1200°C. The conditions for such ‘ultra’-low-temperature sintering are the synthesis of PZT nano-powder through autocombustion route and addition of a small amount of LiBiO2 as a sintering aid. Interestingly, the dielectric and piezoelectric

  6. Ultrasonic and dielectric characterization of microwave-sintered and conventionally sintered zinc oxide

    SciTech Connect

    Martin, L.P.; Dadon, D.; Rosen, M. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Materials Science and Engineering; Gershon, D.; Birman, A.; Levush, B.; Carmel, Y. [Univ. of Maryland, College Park, MD (United States). Lab. for Plasma Research

    1996-10-01

    Zinc oxide samples were prepared by microwave- and conventional-sintering processes using identical time-temperature profiles. Comparison of postsintering properties as a function of residual porosity over the range of 0%--35% indicated no significant difference in the ultrasonic velocity-porosity relations or the elastic moduli for the samples prepared by the two techniques. The real and imaginary parts of the permittivity of the samples processed by the two techniques were measured over a wide frequency range. In both cases, there was an increase in the measured permittivity values with decreasing porosity; however, the microwave-sintered samples had considerably higher values. Porosity levels were evaluated using bulk density measurements and scanning electron microscopy analysis. Significantly more densification was observed at intermediate temperatures for microwave sintering than for conventional sintering.

  7. Sintered electrode for solid oxide fuel cells

    DOEpatents

    Ruka, R.J.; Warner, K.A.

    1999-06-01

    A solid oxide fuel cell fuel electrode is produced by a sintering process. An underlayer is applied to the electrolyte of a solid oxide fuel cell in the form of a slurry, which is then dried. An overlayer is applied to the underlayer and then dried. The dried underlayer and overlayer are then sintered to form a fuel electrode. Both the underlayer and the overlayer comprise a combination of electrode metal such as nickel, and stabilized zirconia such as yttria-stabilized zirconia, with the overlayer comprising a greater percentage of electrode metal. The use of more stabilized zirconia in the underlayer provides good adhesion to the electrolyte of the fuel cell, while the use of more electrode metal in the overlayer provides good electrical conductivity. The sintered fuel electrode is less expensive to produce compared with conventional electrodes made by electrochemical vapor deposition processes. The sintered electrodes exhibit favorable performance characteristics, including good porosity, adhesion, electrical conductivity and freedom from degradation. 4 figs.

  8. Sintering of ash during fluidized bed combustion

    Microsoft Academic Search

    B. J. Bkrifvars; Mikko Hupa; Matti Hiltunen

    1992-01-01

    Agglomeration of bed material and fuel ash may sometimes cause problems during fluidized bed combustion. In this paper a laboratory test method has been applied on different coal ashes to predict how they behave in temperatures typical for circulating fluidized bed boilers. The method is also useful when the influence of the different bed compounds on the sintering is studied

  9. Contact material for pressure-sintering ferrites

    NASA Technical Reports Server (NTRS)

    Wentworth, C.

    1970-01-01

    Pressure-sintering, in which the unfired laminated ferrite plane is placed between two flat punches and pressed during firing, reduces lateral firing shrinkage to less than one percent. A decrease in thickness of the laminate produces the required volume shrinkage. Phlogopite is the most suitable contact material investigated.

  10. SINTERED ALUMINUM PRODUCTS FOR REACTOR APPLICATION

    Microsoft Academic Search

    1961-01-01

    Preliminary examination on sintered aluminum product (SAP) alloys for ; reactor application was carried out by the Metallurgical Laboratory of the AEK. ; The mechanical properties of SAP at elevated temperatures are only slightly ; altered by prolonged heating. Its structural stability is shown to be affected ; by heat treatment at 400 deg C and above. Blistering starts at

  11. Reactive sintering of plutonium-bearing titanates.

    SciTech Connect

    Hash, M. C.

    1999-06-24

    Titanate ceramics are being developed for the immobilization of weapons-grade plutonium. These multi-phase ceramics are intended to be both corrosion and proliferation resistant. Reactive sintering techniques were refined to reproducibly provide titanate ceramics for further characterization and testing. Plutonium-bearing pyrochlore-rich composites were consolidated to greater than 90% of their theoretical density.

  12. Mixing from below in hydrothermal ore deposits

    NASA Astrophysics Data System (ADS)

    Bons, Paul D.; Gomez-Rivas, Enrique; Markl, Gregor; Walter, Bejamin

    2014-05-01

    Unconformity-related hydrothermal ore deposits typically show indications of mixing of two end-member fluids: (a) hot, deep, rock-buffered basement brines and (b) colder fluids derived from the surface or overlying sediments. The hydromechanics of bringing these fluids together from above and below remain unclear. Classical percolative Darcy-flow models are inconsistent with (1) fluid overpressure indicated by fracturing and brecciation, (2) fast fluid flow indicated by thermal disequilibrium, and (3) strong fluid composition variations on the mm-scale, indicated by fluid inclusion analyses (Bons et al. 2012; Fusswinkel et al. 2013). We propose that fluids first descend, sucked down by desiccation reactions in exhumed basement. Oldest fluids reach greatest depths, where long residence times and elevated temperatures allow them the extensively equilibrate with their host rock, reach high salinity and scavenge metals, if present. Youngest fluids can only penetrate to shallower depths and can (partially) retain signatures from their origin, for example high Cl/Br ratios from the dissolution of evaporitic halite horizons. When fluids are released from all levels of the crustal column, these fluids mix during rapid ascent to form hydrothermal ore deposits. Mixing from below provides a viable hydromechanical mechanism to explain the common phenomenon of mixed shallow and deep fluids in hydrothermal ore deposits. Bons, P.D., Elburg, M.A., Gomez-Rivas, E. 2012. A review of the formation of tectonic veins and their microstructures. J. Struct. Geol. doi:10.1016/j.jsg.2012.07.005 Fusswinkel, T., Wagner, T., Wälle, M., Wenzel, T., Heinrich, C.A., Markl, M. 2013. Fluid mixing forms basement-hosted Pb-Zn deposits: Insight from metal and halogen geochemistry of individual fluid inclusions. Geology. doi:10.1130/G34092.1

  13. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Applicability; description of the aluminum ore subcategory. 440.20 Section...AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

  14. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Applicability; description of the aluminum ore subcategory. 440.20 Section...AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

  15. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Applicability; description of the aluminum ore subcategory. 440.20 Section...AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

  16. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Applicability; description of the aluminum ore subcategory. 440.20 Section...AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

  17. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Applicability; description of the aluminum ore subcategory. 440.20 Section...AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

  18. 40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

  19. 40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

  20. 40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

  1. 40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

  2. 40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

  3. 40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Applicability; description of the vanadium ore subcategory. 440.80 Section...MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not... Applicability; description of the vanadium ore subcategory. The...

  4. 40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Applicability; description of the vanadium ore subcategory. 440.80 Section...MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not... Applicability; description of the vanadium ore subcategory. The...

  5. 40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Applicability; description of the vanadium ore subcategory. 440.80 Section...MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not... Applicability; description of the vanadium ore subcategory. The...

  6. 40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Applicability; description of the vanadium ore subcategory. 440.80 Section...MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not... Applicability; description of the vanadium ore subcategory. The...

  7. Uranium ore rolls in the United States

    USGS Publications Warehouse

    Harshman, E.N.

    1970-01-01

    About 40% of the uranium ore reserves in the United States, minable at $8 per pound of contained U3O8, are in roll-type deposits in the State of Wyoming. The host rocks are arkosic sandstones, deposited in intermontane basins under fluvial conditions, and derived from the granitic cores of mountain ranges that flank the basins. The host rocks are Eocene and possibly Paleocene in age and are, or were, overlain by a sequence of continental tuffaceous siltstones, sandstones and conglomerates 400 - 700 m thick.

  8. Sedimentary exhalative nickel-molybdenum ores in south China

    USGS Publications Warehouse

    Lott, D.A.; Coveney, R.M., Jr.; Murowchick, J.B.; Grauch, R.I.

    1999-01-01

    Unique bedded Ni-Mo ores hosted by black shales were discovered in localized paleobasins along the Yangzte platform of southern China in 1971. Textural evidence and radiometric dates imply ore formation during sedimentation of black shales that grade into readily combustible beds, termed stone coals, which contain 10 to 15 percent organic carbon. Studies of 427 fluid inclusions indicate extreme variation in hydrothermal brine salinities that were contained by Proterozoic dolostones underlying the ore zone in Hunan and Guizhou. Variations of fluid inclusion salinities, which range from 0.1 to 21.6 wt percent NaCl equiv, are attributed to differences in the compositions of brines in strata underlying the ore bed, complicated by the presence of seawater and dilute fluids that represent condensates of vapors generated by boiling of mineralizing fluids or Cambrian meteoric water. The complex processes of ore deposition led to scattered homogenization temperatures ranging from 100??to 187??C within the Hunan ore zone and from 65??to 183??C within the Guizhou ore zone. While living organisms probably did not directly accumulate metals in situ in sufficient amounts to explain the unusually high grades of the deposits, sulfur isotope ratios indicate that bacteria, now preserved as abundant microfossils, provided sufficient sulfide for the ores by reduction of seawater sulfate. Such microbiota may have depended on vent fluids and transported organic matter for key nutrients and are consistent with a sedex origin for the ores. Vent fluids interacted with organic remains, including rounded fragments of microbial mats that were likely transported to the site of ore deposition by the action of waves and bottom currents prior to replacement by ore minerals.

  9. Pressureless sintering of whiskered-toughened ceramic composites

    DOEpatents

    Tiegs, T.N.

    1994-12-27

    A pressureless sintering method is disclosed for use in the production of whisker-toughened ceramic composites wherein the sintered density of composites containing up to about 20 vol. % SiC whiskers is improved by reducing the average aspect ratio of the whiskers to from about 10 to about 20. Sintering aids further improve the density, permitting the production of composites containing 20 vol. % SiC with sintered densities of 94% or better of theoretical density by a pressureless sintering method. 6 figures.

  10. Comparative sinterability of combustion synthesized and commercial titanium carbides

    SciTech Connect

    Manley, B.W.

    1984-11-01

    The influence of various parameters on the sinterability of combustion synthesized titanium carbide was investigaged. Titanium carbide powders, prepared by the combustion synthesis process, were sintered in the temperature range 1150 to 1600/sup 0/C. Incomplete combustion and high oxygen contents were found to be the cause of reduced shrinkage during sintering of the combustion syntheized powders when compared to the shrinkage of commercial TiC. Free carbon was shown to inhibit shrinkage. The activation energy for sintering was found to depend on stoichiometry (C/Ti). With decreasing C/Ti, the rate of sintering increased. 29 references, 16 figures, 13 tables.

  11. Load reduction sintering for increasing productivity and decreasing fuel consumption

    NASA Astrophysics Data System (ADS)

    Zuo, Hai-bin; Zhang, Jian-liang; Hu, Zheng-wen; Yang, Tian-jun

    2013-02-01

    The technical and economical indexes and the physical properties of load reduction sintering processes with the supporting stands of installation at different height levels (300, 350, and 400 mm) in a sintering bed were studied under the same conditions of raw material, bed height, and sintering parameters. Sintering pot tests with different bed heights and fuel ratios of the mixture with or without supporting stands were performed to decrease the fuel consumption. The airflow rate through the sintering bed was measured with an anemoscope fixed on the bed surface to reveal the effects of supporting stands. The utilization of load reduction sintering can improve the permeability of the sintering bed, and the airflow rate through the sintering bed is increased. When the stand height is half of the sintering bed, the productivity increases by 27.9%, and the drum index slightly decreases. Keeping at the same productivity level with normal sintering, the utilization of load reduction sintering can decrease the solid fuel consumption by 9.2%.

  12. Neutron diffraction study of the interaction of iron with amorphous fullerite

    NASA Astrophysics Data System (ADS)

    Borisova, P. A.; Agafonov, S. S.; Blanter, M. S.; Somenkov, V. A.

    2014-01-01

    The amorphous fullerite C60 has been prepared by mechanical activation (grinding in a ball mill), and its interaction with iron during sintering of powders with 0-95 at % Fe has been studied. After sintering in the range 800-1200°C under a pressure of 70 MPa, the samples have nonequilibrium structures different from the structures of both annealed and quenched steels. In this case, the carbon phase, i.e., amorphous fullerite, undergoes a polyamorphous transition to amorphous graphite. It has also been shown that the interaction of amorphous fullerite with iron is weaker compared to crystalline fullerite or crystalline graphite.

  13. ARSENOPYRITE MELTING DURING METAMORPHISM OF SULFIDE ORE DEPOSITS

    Microsoft Academic Search

    ANDREW G. TOMKINS; B. RONALD FROST; DAVID R. M. PATTISON

    2006-01-01

    Arsenopyrite is present as a minor phase in many different types of ore deposits. Here we investigate a number of ore deposits metamorphosed to mid-amphibolite facies and above to show that in some environments, arsenopyrite is likely to melt during metamorphism, but in others it will persist until it is converted to löllingite + pyrrhotite. The fate of arsenopyrite is

  14. Routine quantitative phase analysis of niobium-bearing lateritic ores

    Microsoft Academic Search

    Dona Kampata; Jean Naud; Philippe Sonnet

    Routine quantitative analyses by Rietveld full-pattern fitting have been carried out on more than one thousand niobium ore samples originating from four pyrochlore deposits: Lueshe and Bingo (D.R. Congo), Mabounie (Gabon), and Sokli (Finland). The ore samples were characterized by a highly variable mineral content, the presence of mineral phases with a wide range of compositions and a high amorphous

  15. Combined Bridgman and O-Ring Static Pressure Seal

    Microsoft Academic Search

    1960-01-01

    tially square in cross section, resting on a conical portion of the plug. The O-ring provides the initial pressure seal, but when the pressure reaches a sufficient level the last ring starts to flow against the shoulder, giving the usual type of unsupported area seal. The last ring has taken over the sealing job before the O-ring fails. This seal

  16. 25. INTERIOR VIEW LOOKING SOUTH IN THE ORE RECEIVING LEVEL ...

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

    25. INTERIOR VIEW LOOKING SOUTH IN THE ORE RECEIVING LEVEL SHOWING THE TRAMWAY TRACKS IN THE FLOOR, ORE CHUTES IN THE FLOOR, NEWER TRACKS COMING IN FROM THE TRESTLE ON THE EAST SIDE OF THE MILL., AND THE WINDING DRUM THE TRAMWAY IN THE BACKGROUND. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

  17. 40. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also ...

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

    40. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also see OH-18-14, OH-18-38, and OH-18-39) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  18. 39. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also ...

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

    39. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also see OH-18-14, OH-18-38, and OH-18-40) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  19. 24. REAR ELEVATION, HULETT ORE UNLOADERS. TRACKS CARRYING THE FRONT ...

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

    24. REAR ELEVATION, HULETT ORE UNLOADERS. TRACKS CARRYING THE FRONT END AND REAR LEGS OF THE HULETT UNLOADERS ARE LAID ON THE DOCK AND REAR WALLS, RESPECTIVELY; BOTH WALLS ARE MADE OF REINFORCED CONCRETE SUPPORTED ON CONCRETE PILES. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  20. 27. HULETT ORE UNLOADERS TEMPORARILY IN REPOSE, AS A NEW ...

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

    27. HULETT ORE UNLOADERS TEMPORARILY IN REPOSE, AS A NEW SKIP TIES UP AT DOCK. THE UNLOADERS OPERATE ALMOST CONTINUOUSLY DURING THE SHIPPING SEASON, WHICH USUALLY RUNS FROM APRIL UNTIL LATE DECEMBER OR EARLY JANUARY. VIEW HERE IS LOOKING NORTHEAST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

  1. 25. View looking southwest from furnaces shows the ore end ...

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

    25. View looking southwest from furnaces shows the ore end limestone storage bins. Ore and limestone were carried by conveyor, seen at far left, to the tripper car, which in turn distributed them into the trestle bins. - Central Furnaces, 2650 Broadway, east bank of Cuyahoga River, Cleveland, Cuyahoga County, OH

  2. 64. NORTH WALL OF CRUSHED OXIDIZED ORE BIN. THE PRIMARY ...

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

    64. NORTH WALL OF CRUSHED OXIDIZED ORE BIN. THE PRIMARY MILL FEEDS AT BOTTOM. MILL SOLUTION TANKS WERE TO THE LEFT (EAST) AND BARREN SOLUTION TANK TO THE RIGHT (WEST) OR THE CRUSHED ORE BIN. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  3. 19. VIEW OF CRUDE ORE BINS FROM EAST. EAST CRUDE ...

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

    19. VIEW OF CRUDE ORE BINS FROM EAST. EAST CRUDE ORE BIN IN FOREGROUND WITH DISCHARGE TO GRIZZLY AT BOTTOM OF VIEW. CONCRETE RETAINING WALL TO LEFT (SOUTH) AND BOTTOM (EAST EDGE OF EAST BIN). - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  4. TRAM HOUSE INTERIOR, LOOKING SOUTHEAST. NOTE DEPARTING ORE BUCKET "12" ...

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

    TRAM HOUSE INTERIOR, LOOKING SOUTHEAST. NOTE DEPARTING ORE BUCKET "12" AND SUSPENSION CABLE ANGLING DOWN THROUGH FLOOR AT LOWER LEFT. LARGE LEVER ON SIDE OF BUCKET ALLOWS IT TO BE ROTATED FOR DUMPING ORE. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  5. Effects of uranium ore dust on cultured human lung cells.

    PubMed

    Ohshima, S; Xu, Y; Takahama, M

    1998-06-01

    Effects of uranium ore dust on cell proliferation, lipid peroxidation and micronuclei formation were compared with silica (DQ12) and titanium oxide in normal human distal airway epithelial cells (NHDE), human lung cancer cells (A549) and human lung fibroblast cells. Cell proliferation was significantly inhibited with uranium ore dust and silica but not with titanium oxide. Lipid peroxidation was significantly enhanced only with uranium ore dust. Micronuclei formation was significantly stimulated with uranium ore dust in A549 and NHDE cells, but not in fibroblast cells. Silica stimulated micronuclei formation only in A549 cells. The results showed the outstanding effect of uranium ore dust on lipid peroxidation and micronuclei formation in human lung cells compared to silica and titanium dioxide. PMID:21781873

  6. Sintering Phenomena of Lead Magnesium Niobate

    NASA Astrophysics Data System (ADS)

    Costantino, Stephen Allen

    The sintering characteristics of lead magnesium niobate, Pb(Mg_{1/3}Nb _{2/3})O_3 (PMN), were investigated systematically in order to provide an insight into the physical and chemical changes taking place during this process. A controlled-profile sintering technique was used that provided the ability to control sintering profiles to the following extent for heating rates up to 120 ^circC/min: (1) soak temperature: +/-0.5^circC, (2) starting time at temperature (T_0): +/-10 sec, (3) heating rate: +/-2%. This permitted the tracking of densification and microstructural evolution during isothermal sintering, particularly at higher temperatures where the kinetics were rapid. High densities (97-98%) were achieved at temperatures as low as 950^circC when using a heating rate of 120^circC/min. The low sintering temperature is attributed, in part, to the high surface area fissured substructure of the PMN particles resulting from the formation of perovskite PMN via the magnocolumbite method. This led to inhomogeneous densification, and a limit to final density of 98%. It is also proposed that vapor transport influences all stages of sintering and is beneficial to the densification process by providing a source for liquid phase in the early stages, and inhibiting grain growth in all stages. Because of the slow coarsening rates, lower heating rates (investigated down to 5^circC/min.) had no discernable influence on densification kinetics or grain growth. The activation energy for densification in the intermediate stage was 58 kcal/mol and 91 kcal/mol, below and above 85% density, respectively. The change in activation energy is attributed to the preferential removal of the small pore population during inhomogeneous densification. Powders milled for extended periods of time demonstrated more rapid intermediate stage kinetics due to a reduction in the degree of inhomogeneous densification, and an optimization of the densification/grain growth trajectory. Dielectric evaluations demonstrate that dielectric constant is not influenced by grain size in fully dense samples. No influence of thermal profile on the intrinsic contribution to the dielectric constant of dense samples was observed.

  7. Constraints on the composition of ore fluids and implications for mineralising events at the Cleo gold deposit, Eastern Goldfields Province, Western Australia

    USGS Publications Warehouse

    Brown, S.M.; Johnson, C.A.; Watling, R.J.; Premo, W.R.

    2003-01-01

    The Cleo gold deposit, 55 km south of Laverton in the Eastern Goldfields Province of Western Australia, is characterised by banded iron-formation (BIF)-hosted ore zones in the gently dipping Sunrise Shear Zone and high-grade vein-hosted ore in the Western Lodes. There is evidence that gold mineralisation in the Western Lodes (which occurred at ca 2655 Ma) post-dates the majority of displacement along the Sunrise Shear Zone, but it remains uncertain if the ore in both structures formed simultaneously or separately. Overall, the Pb, Nd, Sr, C. O and S isotopic compositions of ore-related minerals from both the Western Lodes and ore zones in the Sunrise Shear Zone are similar. Early low-salinity aqueous-carbonic fluids and late high-salinity fluids with similar characteristics are trapped in inclusions in quartz veins from both the Sunrise Shear Zone and the Western Lodes. The early CO2, CO2-H2O, and H2O- dominant inclusions are interpreted as being related to ore formation, and to have formed from a single low-salinity aqueous-carbonic fluid as a result of intermittent fluid immiscibility. Homogenisation temperatures indicate that these inclusions were trapped at approximately 280??C and at approximately 4 km depth, in the deeper epizonal range. Differences between the ore zones are detected in the trace-element composition of gold samples, with gold from the Sunrise Shear Zone enriched in Ni, Pb, Sn, Te and Zn, and depleted In As, Bi, Cd, Cu and Sb, relative to gold from the Western Lodes. Although there are differences in gold composition between the Sunrise Shear Zone and Western Lodes, and hence the metal content of ore fluids may have varied slightly between the different ore zones, no other systematic fluid or solute differences are detected between the ore zones. Given the fact that the ore fluids in each zone have very similar bulk properties, the considerable differences in gold grade, sulfide mineral abundance, and ore textures between the two ore zones most likely result from different gold-deposition mechanisms. The association of ore zones in the Sunrise Shear Zone with pyrite-replaced BIF suggests that wall-rock sulfidation was the most significant mechanism of gold precipitation, through the destabilisation of gold-bisulfide complexes. The Western Lodes, however, do not exhibit any host-rock preference and multistage veins commonly contain coarse-grained gold. Fluid-inclusion characteristics and breccia textures in veins in the Western Lodes suggest that rapid pressure changes, brought about by intermittent release of overpressured fluids and concomitant phase separation, are likely to have caused the destabilisation of gold-thiocomplexes, leading to formation of higher-grade gold ore zones.

  8. Bacterial iron homeostasis

    Microsoft Academic Search

    Simon C Andrews; Andrea K Robinson; Francisco Rodr??guez-Quiñones

    2003-01-01

    Iron is essential to virtually all organisms, but poses problems of toxicity and poor solubility. Bacteria have evolved various mechanisms to counter the problems imposed by their iron dependence, allowing them to achieve effective iron homeostasis under a range of iron regimes. Highly efficient iron acquisition systems are used to scavenge iron from the environment under iron-restricted conditions. In many

  9. Preparation of high sinterable lithium metasilicate

    NASA Astrophysics Data System (ADS)

    Flipot, A. J.; Diels, P.; Lecocq, R.

    1985-08-01

    A new approach has been developed to produce sinterable lithium metasilicate in order to fabricate high density ( > 90% TD) pellets by cold compaction and sintering. Lithium carbonate and silica are intimately milled, spray-dried, pre-calcined and calcined. Precalcination under wet air at about 430°C has led to the discovery of a hexagonal X-phase, the formation of which is the key to the process. The X-phase can in fact easily be transformed by a calcination below 600°C into a high reactive metasilicate containing no disilicate nor orthosilicate, which is not possible by direct calcination. The effects of temperature, time and atmosphere on the formation of the X-phase are discussed.

  10. Sintering aid for lanthanum chromite refractories

    DOEpatents

    Flandermeyer, Brian K. (Bolingbrook, IL); Poeppel, Roger B. (Glen Ellyn, IL); Dusek, Joseph T. (Downers Grove, IL); Anderson, Harlan U. (Rolla, MO)

    1988-01-01

    An electronically conductive interconnect layer for use in a fuel cell or other electrolytic device is formed with sintering additives to permit densification in a monolithic structure with the electrode materials. Additions including an oxide of boron and a eutectic forming composition of Group 2A metal fluorides with Group 3B metal fluorides and Group 2A metal oxides with Group 6B metal oxides lower the required firing temperature of lanthanum chromite to permit densification to in excess of 94% of theoretical density without degradation of electrode material lamina. The monolithic structure is formed by tape casting thin layers of electrode, interconnect and electrolyte materials and sintering the green lamina together under common densification conditions.

  11. Porous sintered materials from stainless steel

    Microsoft Academic Search

    R. A. Andrievskii; V. S. Pugin; I. M. Fedorchenko; B. Z. Teverovskii

    1965-01-01

    1.A method is proposed for the production of long, high-porosity tubes from nonspherical stainless steel powders.2.A study was made of the mechanical, electrical, and chemical properties of porous stainless steel. From the point of view of permeability, specimens made by die extrusion are approximately equivalent to those made by sintering freely-poured atomized powder.3.A method is proposed for the evaluation of

  12. Microwave sintering of alumina–zirconia nanocomposites

    Microsoft Academic Search

    R. R. Menezes; R. H. G. A. Kiminami

    2008-01-01

    This work involved an investigation of microwave hybrid fast firing of alumina–zirconia nanocomposites aimed at suppressing grain growth, using commercial alumina powder and yttria-stabilized zirconia powder. The nanocomposites studied here contained 1, 3 and 5vol.% of zirconia. The powders were ball-mixed and compacted under cold isostatic pressure at 200MPa. The samples were microwave hybrid fast sintered in a multimode microwave

  13. Liquid phase sintered compacts in space

    NASA Technical Reports Server (NTRS)

    Mookherji, T. K.; Mcanelly, W. B.

    1974-01-01

    A model that will explain the effect of gravity on liquid phase sintering was developed. Wetting characteristics and density segregation which are the two important phenomena in liquid phase sintering are considered in the model development. Experiments were conducted on some selected material combinations to study the gravity effects on liquid phase sintering, and to verify the validity of the model. It is concluded that: (1) The surface tension forces acting on solid particles in a one-g environment are not appreciably different from those anticipated in a 0.00001g/g sub 0 (or lower) environment. (2) The capillary forces are dependent on the contact angle, the quantity of the liquid phase, and the distance between solid particles. (3) The pores (i.e., bubbles) do not appear to be driven to the surface by gravity-produced buoyancy forces. (4) The length of time to produce the same degree of settling in a low-gravity environment will be increased significantly. (5) A low gravity environment would appear to offer a unique means of satisfactorily infiltrating a larger and/or complex shaped compact.

  14. Thermoelectric Coolers with Sintered Silver Interconnects

    NASA Astrophysics Data System (ADS)

    Kähler, Julian; Stranz, Andrej; Waag, Andreas; Peiner, Erwin

    2014-06-01

    The fabrication and performance of a sintered Peltier cooler (SPC) based on bismuth telluride with sintered silver interconnects are described. Miniature SPC modules with a footprint of 20 mm2 were assembled using pick-and-place pressure-assisted silver sintering at low pressure (5.5 N/mm2) and moderate temperature (250°C to 270°C). A modified flip-chip bonder combined with screen/stencil printing for paste transfer was used for the pick-and-place process, enabling high positioning accuracy, easy handling of the tiny bismuth telluride pellets, and immediate visual process control. A specific contact resistance of (1.4 ± 0.1) × 10-5 ? cm2 was found, which is in the range of values reported for high-temperature solder interconnects of bismuth telluride pellets. The realized SPCs were evaluated from room temperature to 300°C, considerably outperforming the operating temperature range of standard commercial Peltier coolers. Temperature cycling capability was investigated from 100°C to 235°C over more than 200 h, i.e., 850 cycles, during which no degradation of module resistance or cooling performance occurred.

  15. Ceramic components manufacturing by selective laser sintering

    NASA Astrophysics Data System (ADS)

    Bertrand, Ph.; Bayle, F.; Combe, C.; Goeuriot, P.; Smurov, I.

    2007-12-01

    In the present paper, technology of selective laser sintering/melting is applied to manufacture net shaped objects from pure yttria-zirconia powders. Experiments are carried out on Phenix Systems PM100 machine with 50 W fibre laser. Powder is spread by a roller over the surface of 100 mm diameter alumina cylinder. Design of experiments is applied to identify influent process parameters (powder characteristics, powder layering and laser manufacturing strategy) to obtain high-quality ceramic components (density and micro-structure). The influence of the yttria-zirconia particle size and morphology onto powder layering process is analysed. The influence of the powder layer thickness on laser sintering/melting is studied for different laser beam velocity V ( V = 1250-2000 mm/s), defocalisation (-6 to 12 mm), distance between two neighbour melted lines (so-called "vectors") (20-40 ?m), vector length and temperature in the furnace. The powder bed density before laser sintering/melting also has significant influence on the manufactured samples density. Different manufacturing strategies are applied and compared: (a) different laser beam scanning paths to fill the sliced surfaces of the manufactured object, (b) variation of vector length (c) different strategies of powder layering, (d) temperature in the furnace and (e) post heat treatment in conventional furnace. Performance and limitations of different strategies are analysed applying the following criteria: geometrical accuracy of the manufactured samples, porosity. The process stability is proved by fabrication of 1 cm 3 volume cube.

  16. Preservation of Microbial Lipids in Geothermal Sinters

    NASA Astrophysics Data System (ADS)

    Kaur, Gurpreet; Mountain, Bruce W.; Hopmans, Ellen C.; Pancost, Richard D.

    2011-04-01

    Lipid biomarkers are widely used to study the earliest life on Earth and have been invoked as potential astrobiological markers, but few studies have assessed their survival and persistence in geothermal settings. Here, we investigate lipid preservation in active and inactive geothermal silica sinters, with ages of up to 900 years, from Champagne Pool, Waiotapu, New Zealand. Analyses revealed a wide range of bacterial biomarkers, including free and bound fatty acids, 1,2-di-O-alkylglycerols (diethers), and various hopanoids. Dominant archaeal lipids include archaeol and glycerol dialkyl glycerol tetraethers (GDGTs). The predominance of generally similar biomarker groups in all sinters suggests a stable microbial community throughout Champagne Pool's history and indicates that incorporated lipids can be well preserved. Moreover, subtle differences in lipid distributions suggest that past changes in environmental conditions can be elucidated. In this case, higher archaeol abundances relative to the bacterial diethers, a greater proportion of cyclic GDGTs, the high average chain length of the bacterial diethers, and greater concentrations of hopanoic acids in the older sinters all suggest hotter conditions at Champagne Pool in the past.

  17. Microwave treatment of a brown coal concentrate from Mugunsk coal for the manufacture of sponge iron

    SciTech Connect

    A.A. Khaidurova; P.N. Konovalov; N.P. Konovalov [Irkutsk State Technical University, Irkutsk (Russia)

    2008-04-15

    A technique for the production of a finely dispersed dry brown coal concentrate with the use of microwave energy is proposed to prepare a charge mixture for the manufacture of sponge iron. The advantages of this technique over analogous industrial processes are demonstrated. The results of experiments on the briquetting of the charge mixture of brown coal and iron ore concentrates without the use of an additional binding agent are described.

  18. Extraction of titanium, vanadium and iron from titanomagnetite deposits at pipestone lake, Manitoba, Canada

    Microsoft Academic Search

    B. C. Jena; W. Dresler; I. G. Reilly

    1995-01-01

    A process has been developed at the laboratory scale for the recovery of titanium, vanadium and iron from the vanadium bearing titanomagnetite deposit at Pipestone Lake, Manitoba, by combined pyro- and hydrometallurgical processing route. The ore which contains 57.5% Fe, 0.66% V and 16.6% TiO2 was subjected to selective reduction smelting so that most of the iron reported to the

  19. Alteration mineral mapping for iron prospecting using ETM+ data, Tonkolili iron field, northern Sierra Leone

    NASA Astrophysics Data System (ADS)

    Mansaray, Lamin R.; Liu, Lei; Zhou, Jun; Ma, Zhimin

    2013-10-01

    The Tonkolili iron field in northern Sierra Leone has the largest known iron ore deposit in Africa. It occurs in a greenstone belt in an Achaean granitic basement. This study focused mainly on mapping areas with iron-oxide and hydroxyl bearing minerals, and identifying potential areas for haematite mineralization and banded iron formations (BIFs) in Tonkolili. The predominant mineral assemblage at the surface (laterite duricrust) of this iron field is haematitegoethite- limonite ±magnetite. The mineralization occurs in quartzitic banded ironstones, layered amphibolites, granites, schists and hornblendites. In this study, Crosta techniques were applied on Enhanced Thematic Mapper (ETM+) data to enhance areas with alteration minerals and target potential areas of haematite and BIF units in the Tonkolili iron field. Synthetic analysis shows that alteration zones mapped herein are consistent with the already discovered magnetite BIFs in Tonkolili. Based on the overlaps of the simplified geological map and the remote sensing-based alteration mineral maps obtained in this study, three new haematite prospects were inferred within, and one new haematite prospect was inferred outside the tenement boundary of the Tonkolili exploration license. As the primary iron mineral in Tonkolili is magnetite, the study concludes that, these haematite prospects could also be underlain by magnetite BIFs. This study also concludes that, the application of Crosta techniques on ETM+ data is effective not only in mapping iron-oxide and hydroxyl alterations but can also provide a basis for inferring areas of potential iron resources in Algoma-type banded iron formations (BIFs), such as those in the Tonkolili field.

  20. Sintering dense NiZn ferrite by two-step sintering process

    NASA Astrophysics Data System (ADS)

    Su, Hua; Tang, Xiaoli; Zhang, Huaiwu; Zhong, Zhiyong; Shen, Jian

    2011-04-01

    A two-step sintering process has been adopted to produce NiZn ferrite with composition of (NiO)0.35(ZnO)0.57(CuO)0.08(Fe2O3). The densification, microstructure, and magnetic properties of the ferrite have been investigated and compared with those of ferrites produced by the traditional final-stage sintering process. It was found that the sample produced by a two-step sintering process with a high temperature of 1200 °C and a lower temperature of 1100 °C attained more than 96% of the theoretical density and had a uniform microstructure with a small average grain size. It also exhibited good performances in terms of permeability and Q-factor. Hence, this would seem to be an effective method for producing dense ferrites with a microstructure composed of small and even grains, which is a very effective strategy for improving the magnetic properties of ferrites.

  1. Sulfur isotope geochemistry of ore and gangue minerals from the Silesian-Cracow Mississippi Valley-type ore district, Poland

    USGS Publications Warehouse

    Leach, D.L.; Vets, J.G.; Gent, C.A.

    1996-01-01

    Studies of the sulfur isotopic composition of ore and gangue minerals from the Silesian-Cracow Zn-Pb district were conducted to gain insights into processes that controlled the location and distribution of the ore deposits. Results of this study show that minerals from the Silesian-Cracow ore district have the largest range of sulfur isotope compositions in sulfides observed from any Mississippi Valley-type ore district in the world. The ??34S values for sulfide minerals range from +38 to -32 per mil for the entire paragenetic sequence but individual stages exhibit smaller ranges. There is a well developed correlation between the sulfur isotope composition and paragenetic stage of ore deposition. The first important ore stage contains mostly positive ??34S values, around 5 per mil. The second stage of ore formation are lower, with a median value of around -5 to -15 per mil, and with some values as low as -32 per mil. Late stage barite contains isotopically heavy sulfur around +32 per mil. The range in sulfur isotope compositions can be explained by contributions of sulfur from a variety of source rocks together with sulfur isotope fractionations produced by the reaction paths for sulfate reduction. Much of the variation in sulfur isotope compositions can be explained by bacterial reduction of sedimentary sulfate and disequilibrium reactions by intermediate-valency sulfur species, especially in the late-stage pyrite and sphalerite. Organic reduction of sulfate and thermal release of sulfur from coals in the Upper Silesian Coal Basin may have been important contributors to sulfur in the ore minerals. The sulfur isotopic data, ore mineral textures, and fluid inclusion data, are consistent with the hypothesis that fluid mixing was the dominant ore forming mechanism. The rather distinct lowering of ?? 34S values in sulfides from stage 2 to stage 3 is believed to reflect some fundamental change in the source of reduced sulfur and/or hydrology of the ore-forming environment. A change in the hydrology of the ore forming environment could be accomplished by extensional faulting that was coeval with ore formation. Late stage barite contains high values of ??34S which may reflect the final collapse of the hydrothermal system.

  2. COLLAPSE/SUBSIDENCE: ROLE AND INFLUENCE OF OVERBURDEN IN LORRAINE IRON MINES CASE

    E-print Network

    Paris-Sud XI, Université de

    COLLAPSE/SUBSIDENCE: ROLE AND INFLUENCE OF OVERBURDEN IN LORRAINE IRON MINES CASE FOUGERON Jérôme1 ore basin, in particular 8 violent collapses and 8 progressive subsidences. It is important to distinguish violent collapses of progressive subsidences, implications in terms of person security being very

  3. Accelerated sintering in phase-separating nanostructured alloys

    PubMed Central

    Park, Mansoo; Schuh, Christopher A.

    2015-01-01

    Sintering of powders is a common means of producing bulk materials when melt casting is impossible or does not achieve a desired microstructure, and has long been pursued for nanocrystalline materials in particular. Acceleration of sintering is desirable to lower processing temperatures and times, and thus to limit undesirable microstructure evolution. Here we show that markedly enhanced sintering is possible in some nanocrystalline alloys. In a nanostructured W–Cr alloy, sintering sets on at a very low temperature that is commensurate with phase separation to form a Cr-rich phase with a nanoscale arrangement that supports rapid diffusional transport. The method permits bulk full density specimens with nanoscale grains, produced during a sintering cycle involving no applied stress. We further show that such accelerated sintering can be evoked by design in other nanocrystalline alloys, opening the door to a variety of nanostructured bulk materials processed in arbitrary shapes from powder inputs. PMID:25901420

  4. Sintered Cu Alloyed Stainless Steels and Their Corrosion Behavior

    NASA Astrophysics Data System (ADS)

    Wang, Jun'an; He, Ying; He, Peng; Zhou, Bangxin

    2008-10-01

    Copper is an effective element to activate the sintering process of stainless steels and to enhance corrosion resistance of the sintered specimens. Ways of introducing Cu into stainless steel powders lead to different consequence in the microstructure and corrosion behavior of sintered Cu alloyed stainless steel. In the present work, two methods, mixing Cu with stainless steel powder and coating stainless steel powder with Cu by electroless plating, were introduced in order to investigate their influence on the sintered specimens. It was found that the sintered specimens from Cu-coated stainless steel powders (1-5 wt.%Cu) produce less porous surfaces with isolated pores than the specimens from mixed powders and the former have obviously high density and relatively even Cu distribution. Potentiodynamic polarization measurements indicate that Cu-electroless plating of 1-5 wt.%Cu improves the corrosion resistance of sintered stainless steel due to the lowering of passivation current density.

  5. XPS characterisation of ceria-stabilised zirconia doped with iron oxide

    NASA Astrophysics Data System (ADS)

    Nascente, Pedro A. P.; de Souza, Dulcina P. F.

    1999-04-01

    The addition of iron oxide on ceria-stabilised zirconia was studied by X-ray photoelectron spectroscopy (XPS). Zirconia presents a monoclinic to tetragonal phase transition at 1443 K, which is accompanied by a volume variation of approximately 3-5%, preventing the formation of a dense polycrystalline monoclinic ceramic. Ceria-stabilised tetragonal zirconia presents high toughness and can be applied as a structural material. However, CeO 2-ZrO 2 has low sinterability, so it is important to investigate the effect of sintering dopants, such as iron, copper and manganese ions, which could improve the sinterability and the mechanical properties of the ceramic. In previous studies, it was shown that the addition of 0.3 mol% of Fe 2O 3 helped in sintering the ceramic, and enhanced the electrical conductivity, although it was not determined if this enhancement was due to ionic or electronic contribution. In this work, we employed XPS to characterise ZrO 2+ x mol% CeO 2+0.3 mol% Fe 2O 3, x=12 and 20, ceramics sintered at 1450 and 1600°C in order to better understand the influence of iron in the stabilisation of the tetragonal phase and electrical conductivity.

  6. Mechanism of Sintering YAG\\/ZrB2 Multiphase Ceramics with Spark Plasma Sintering

    Microsoft Academic Search

    Jieguang Song; Junguo Li; Jianrong Song; Lianmeng Zhang

    2008-01-01

    Although ZrB2 has some excellent performances, it is difficult to prepare the high relative-density ZrB2 ceramics, which limits the application of ZrB2 materials. To obtain higher relative-density ZrB2 ceramics for increasing the good oxidation resistance, YAG\\/ZrB2 multiphase ceramics is prepared with the spark plasma sintering, the sintering mechanism of preparing YAG\\/ZrB2 multiphase ceramic materials is investigated. Al2O3 reacts with Y2O3

  7. Tourmaline as a recorder of ore-forming processes

    USGS Publications Warehouse

    Slack, J.F.; Trumbull, R.B.

    2011-01-01

    Tourmaline occurs in diverse types of hydrothermal mineral deposits and can be used to constrain the nature and evolution of ore-forming fl uids. Because of its broad range in composition and retention of chemical and isotopic signatures, tourmaline may be the only robust recorder of original mineralizing processes in some deposits. Microtextures and in situ analysis of compositional and isotopic variations in ore-related tourmaline provide valuable insights into hydrothermal systems in seafl oor, sedimentary, magmatic, and metamorphic environments. Deciphering the hydrothermal record in tourmaline also holds promise for aiding exploration programs in the search for new ore deposits.

  8. Water leaching of titanium from ore flotation residue

    SciTech Connect

    Jaworska, Malgorzata M.; Guibal, Eric

    2003-07-01

    Copper ore tailings were tested for the stability of titanium submitted to water leaching in three different reactor systems (agitated vessel, bioreactor and percolated fixed-bed column). For each of these systems, titanium extraction did not exceed 1% of the available metal. Biomass removed from ore residue adsorbed a small part of the titanium with sorption capacities below 20-30 mg g{sup -1}, but most of this biomass was sequestered in the ore residue. Oxygen and carbon dioxide concentrations were monitored and changes in concentration correlated with bacteria development at the initial stage of the process and to fungal development in the latter stages.

  9. Evolution of the fractal dimension for simultaneous coagulation and sintering

    Microsoft Academic Search

    Hans-Joachim Schmid; Belal Al-Zaitone; Christian Artelt; Wolfgang Peukert

    2006-01-01

    Simulation results on the evolution of aggregate structure in aerosol processes with coagulation and sintering as the dominant mechanisms are presented. A model for simulation of the three-dimensional morphology of nano-structured aggregates formed by concurrent coagulation and sintering is applied. The model is based on a stochastic diffusion controlled cluster–cluster aggregation algorithm and sintering is modeled as a successive overlapping

  10. A New Monte Carlo Model for Supported-Catalyst Sintering

    Microsoft Academic Search

    Allen G. Sault; Veena Tikare

    2002-01-01

    We present a new 2D Monte Carlo model of supported-catalyst sintering that is capable of generating all known catalyst sintering behaviors, including atom emission and recapture (Ostwald ripening), particle migration and coalescence, and vapor-phase transport. This model differs from previously reported phenomenological models in that no mechanism is presupposed; rather sintering is allowed to arise naturally from atomic-scale interactions among

  11. Contactless Electrical Sintering of Silver Nanoparticles on Flexible Substrates

    Microsoft Academic Search

    Mark Allen; Ari Alastalo; Mika Suhonen; Tomi Mattila; Jaakko Leppaniemi; Heikki Seppa

    2011-01-01

    Contactless rapidelectrical sintering (RES) is demon- strated using microwave power. The method is implemented by coupling the near-field electric field of a sintering head across an underlying nanoparticle layer. We provide appropriate biasing conditions required for controlled powerdeliveryand demonstrate real-time monitoring of the process by measuring the reflected power at 1.8 GHz. A small-scale sintering head is designed and fabricated

  12. Surface oxide debonding in field assisted powder sintering

    Microsoft Academic Search

    K. R Anderson; J. R Groza; M Fendorf; C. J Echer

    1999-01-01

    Field activated sintering techniques (FAST) have been applied to two high-temperature powder materials: tungsten and NiAl. High and atomic resolution electron microscopy (HREM\\/ARM) of tungsten powder sintered via FAST showed essentially clean boundaries. Analytical transmission electron microscopy (TEM) of FAST sintered NiAl also showed boundaries free of surface oxide layer(s). However, small alumina precipitates were found at and near prior

  13. Modelling of the temperature distribution during field assisted sintering

    Microsoft Academic Search

    K. Vanmeensel; A. Laptev; J. Hennicke; J. Vleugels; O. Van der Biest

    2005-01-01

    The evolution of the current density and temperature distribution in the punch-die-sample set-up during field activated sintering (FAST), also known as spark plasma sintering or pulsed electric current sintering, was modelled by finite element calculations supported by in situ measured electrical and thermal input data. The thermal and electrical resistances induced by the contacts of the different constituent parts of

  14. Temperature field distribution in Spark Plasma Sintering of BN

    Microsoft Academic Search

    Wang Yu-cheng; Fu Zheng-yi; Wang Wei-ming; Zhu Han-xiong

    2002-01-01

    This paper studies the temperature distribution of BN, an insulating material, sintered in the Spark Plasma Sintering (SPS)\\u000a system. The temperature distributions of BN at different heating rates were measured, which showed that seeking for an over\\u000a high heating rate in SPS is not as desirable as controlling of a suitable heating rate in order to have a fast sintering

  15. Ore mineralogy of nickel laterites: controls on processing characteristics under simulated heap-leach conditions

    Microsoft Academic Search

    H. R. Watling; A. D. Elliot; H. M. Fletcher; D. J. Robinson; D. M. Sully

    2011-01-01

    The mineral phases in more than 50 Ni laterite ores were determined before and after the ores were acid-leached in columns for more than 120 days. The selected ore samples have wide variations in initial chemical and mineralogical compositions and other properties, and their behaviour during treatment, including the proportions of Ni and Co extracted, exhibit similar extreme variations. Ores

  16. Chemical heat treatment of powder materials based on iron

    Microsoft Academic Search

    A. P. Épik; A. Madzhid

    1993-01-01

    Diffusion chromizing and boriding of iron-base powder materials SP30, SP90, and SP90D3 are studied. The growth kinetics for diffusion layers are determined depending on diffusion impregnation conditions, and material composition and porosity. Comparative bending and tensile strength tests as well as wear- and heat-resistance tests for materials after sintering by standard conditions or boriding and chromizing are performed. It is

  17. Iron and alloys of iron. [lunar resources

    NASA Technical Reports Server (NTRS)

    Sastri, Sankar

    1992-01-01

    All lunar soil contains iron in the metallic form, mostly as an iron-nickel alloy in concentrations of a few tenths of 1 percent. Some of this free iron can be easily separated by magnetic means. It is estimated that the magnetic separation of 100,000 tons of lunar soil would yield 150-200 tons of iron. Agglutinates contain metallic iron which could be extracted by melting and made into powder metallurgy products. The characteristics and potential uses of the pure-iron and iron-alloy lunar products are discussed. Processes for working iron that might be used in a nonterrestrial facility are also addressed.

  18. Effects of Mg doping and sintering temperature on the magnetoresistance of sintered Fe3O4 ferrites

    Microsoft Academic Search

    C. T. Lie; P. C. Kuo; A. C. Sun; C. Y. Chou; S. C. Chen; I. J. Chang; T. H. Wu; J. W. Chen

    2003-01-01

    Fe3O4 powder was mixed with MgO powder and then sintered in an atmosphere of argon at various temperatures for 3 h to form Mg-doped Fe3O4 ferrites. The effects of the sintering temperature, microstructure, and Mg content on the magnetoresistance of sintered Fe3O4 ferrites were investigated. X-ray diffraction and chemical titration analysis of Fe2+ and Fe3+ ions indicate that the nonstoichiometric

  19. Comparison of ultra-fast microwave sintering and conventional thermal sintering in manufacturing of anode support solid oxide fuel cell

    Microsoft Academic Search

    Zhenjun Jiao; Naoki Shikazono; Nobuhide Kasagi

    2010-01-01

    Ultra-fast microwave sintering in a multi-mode domestic microwave oven with selective susceptor and spacer has been proved to be an effective and facile method in the manufacturing of anode support solid oxide fuel cell (SOFC). Two anode support SOFCs were fabricated by using ultra-fast microwave sintering and conventional thermal sintering techniques, separately. The performances of the two cells were measured

  20. Mechanism of fatigue performance enhancement in a laser sintered superhard nanoparticles reinforced nanocomposite followed by laser shock peening

    NASA Astrophysics Data System (ADS)

    Lin, Dong; Ye, Chang; Liao, Yiliang; Suslov, Sergey; Liu, Richard; Cheng, Gary J.

    2013-04-01

    This study investigates the fundamental mechanism of fatigue performance enhancement during a novel hybrid manufacturing process, which combines laser sintering of superhard nanoparticles integrated nanocomposites and laser shock peening (LSP). Through laser sintering, TiN nanoparticles are integrated uniformly into iron matrix to form a nanocomposite layer near the surface of AISI4140 steel. LSP is then performed on the nanocomposite layer to generate interaction between nanoparticles and shock waves. The fundamental mechanism of fatigue performance enhancement is discussed in this paper. During laser shock interaction with the nanocomposites, the existence of nanoparticles increases the dislocation density and also helps to pin the dislocation movement. As a result, both dislocation density and residual stress are stabilized, which is beneficial for fatigue performance.

  1. 53. VIEW OF CRUSHED OXIDIZED ORE BIN FROM EAST. SHOWS ...

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

    53. VIEW OF CRUSHED OXIDIZED ORE BIN FROM EAST. SHOWS ACCESS STAIR TO FEED LEVEL; DUST COLLECTOR ON LEFT. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

  2. 43. PHOTOCOPY OF DRAWING OF THE MINE ORE BIN AND ...

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

    43. PHOTOCOPY OF DRAWING OF THE MINE ORE BIN AND LOADING TERMINAL, CROSS SECTION AND SIDE ELEVATION - Kennecott Copper Corporation, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

  3. 44. PHOTOCOPY OF DRAWING OF THE MINE ORE BIN AND ...

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

    44. PHOTOCOPY OF DRAWING OF THE MINE ORE BIN AND LOADING TERMINAL, CROSS SECTION AND SIDE ELEVATION - Kennecott Copper Corporation, On Copper River & Northwestern Railroad, Kennicott, Valdez-Cordova Census Area, AK

  4. RUSTING ORE TRAIN, ONCE PART OF NEW YORK ELEVATED LINE ...

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

    RUSTING ORE TRAIN, ONCE PART OF NEW YORK ELEVATED LINE (TWO LOCOMOTIVES, SHOWING RAILROAD TRUCKS IN FOREGROUND) - Council City & Solomon River Railroad, Locomotives, Nome Vicinity, Nome, Nome Census Area, AK

  5. VIEW FACING EAST. ORE TRESTLE WINDS AROUND THE INGOT MOLD ...

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

    VIEW FACING EAST. ORE TRESTLE WINDS AROUND THE INGOT MOLD CONDITIONING BUILDING IN FOREGROUND. PITTSBURGH & LAKE ERIE TRACKS WIND THROUGH TOWN TOWARDS PITTSBURGH AT RIGHT. - Pittsburgh Steel Company, Monessen Works, Donner Avenue, Monessen, Westmoreland County, PA

  6. [NOx and SO2 formation in the sintering process and influence of sintering material composition on NOx emissions].

    PubMed

    Ren, Zhong-Pei; Zhu, Tian-Le; Zhu, Ting-Yu; Lü, Dong

    2014-10-01

    NOx and SO2 formation in the sintering process and the influence of coke powder content, moisture content and adding additives on NO emissions were investigated by the sintering pot experimental method. The results showed that the combustion zone moved downward along the sintering pot after the sintering started. The NOx concentrations of all monitoring points below the combustion zone were basically the same. SO2 generated in the combustion zone was adsorbed and accumulated in the sintering materials below the zone. Then, SO2 was released by pyrolysis, and finally discharged from the outlet of sintering pot. So the significant SO2 couldn't be detected before the burning through point, and the relationship between the SO2 concentration and the sintering time displayed an inverted "V" curve. NOx produced from the sintering process was mainly thermal-NOx, and most of it was NO, the NO2 concentration was very low. Reducing the coke powder and moisture contents, or adding sintering additives could effectively reduce NOx emissions. PMID:25693368

  7. Master sintering curves for UO2 and UO2-SiC composite processed by spark plasma sintering

    NASA Astrophysics Data System (ADS)

    Chen, Zhichao; Subhash, Ghatu; Tulenko, James S.

    2014-11-01

    Master sintering curve (MSC) theory has been applied successfully to UO2 and UO2-SiC composite ceramics processed using spark plasma sintering (SPS). By applying the constant heating rate method, where the powder compact was heated at a constant rate to a specified maximum temperature and then cooled naturally, the apparent activation energies for sintering have been determined to be 140 kJ/mol for UO2 and 420 kJ/mol for UO2-SiC composite. The ability of the derived MSCs to control and predict final density in the sintered compact was demonstrated by additional experimental runs using the isothermal heating method, in which the powder is held for a specified time at the maximum sintering temperature. It is shown that the master sintering curve is an effective tool to characterize the densification and sinterability behavior of a given nuclear powder compact during spark plasma sintering. The reason for significantly lower activation energy in SPS processed UO2 pellets compared to conventional sintering has been rationalized on the basis of field activation in SPS process.

  8. Predicting the lifetime of fluorosilicone o-rings

    Microsoft Academic Search

    R. Bernstein; K. T. Gillen

    2009-01-01

    Long-term (up to 1000 days) accelerated oven-aging studies on a commercial fluorosilicone o-ring seal are used to predict the sealing lifetime at room temperature (23 °C). The study follows force decay (relaxation) on squeezed o-ring material using isothermal compression stress relaxation (CSR) techniques. The relaxation is normally a complex mix of reversible physical effects and non-reversible chemical effects but we utilize

  9. Predicting the lifetime of fluorosilicone O-rings

    Microsoft Academic Search

    Kenneth Todd Gillen; Robert Bernstein

    2008-01-01

    Long-term (up to 1000 days) accelerated oven-aging studies on a commercial fluorosilicone o-ring seal are used to predict the sealing lifetime at room temperature (23 C). The study follows force decay (relaxation) on squeezed o-ring material using isothermal compression stress relaxation (CSR) techniques. The relaxation is normally a complex mix of reversible physical effects and non-reversible chemical effects but we

  10. Accelerated thermal ageing studies on nitrile rubber O-rings

    Microsoft Academic Search

    P. R. Morrell; M. Patel; A. R. Skinner

    2003-01-01

    Poly(acrylonitrile-butadiene) rubber (NBR) O-rings have been aged in air whilst under 12.5% compression at temperatures up to 110 °C. The compression set properties together with oxygen uptake of the O-rings under the applied load conditions were measured and results analysed using time-temperature superposition and Arrhenius kinetics. The compression set results suggest a single degradation process with an activation energy of

  11. Making Reliable Large-Diameter O-Rings

    NASA Technical Reports Server (NTRS)

    Larsen, Glade L.; Harvey, Albert R.

    1989-01-01

    Vacuum curing yields joint-free, voidless elastomer seals. Method for manufacturing large-diameter O-rings produces them in single pieces, without bonded joints. Reduces probability trapped gases form flaws. O-rings produced, having diameters as much as 144 in. (3.66m), reliable and of high quality. Nesting upper and lower halves of mold hold elastomer rings for curing. Oil flowing through upper and lower cavities heats elastomer to cure it.

  12. AGING PERFORMANCE OF MODEL 9975 PACKAGE FLUOROELASTOMER O-RINGS

    Microsoft Academic Search

    E. Hoffman; W. Daugherty; E. Skidmore; K. Dunn; D. Fisher

    2011-01-01

    The influence of temperature and radiation on Viton{reg_sign} GLT and GLT-S fluoroelastomer O-rings is an ongoing research focus at the Savannah River National Laboratory. The O-rings are credited for leaktight containment in the Model 9975 shipping package used for transportation of plutonium-bearing materials. At the Savannah River Site, the Model 9975 packages are being used for interim storage. Primary research

  13. LIFETIME PREDICTION FOR MODEL 9975 O-RINGS IN KAMS

    Microsoft Academic Search

    E. Hoffman; E. Skidmore

    2009-01-01

    The Savannah River Site (SRS) is currently storing plutonium materials in the K-Area Materials Storage (KAMS) facility. The materials are packaged per the DOE 3013 Standard and transported and stored in KAMS in Model 9975 shipping packages, which include double containment vessels sealed with dual O-rings made of Parker Seals compound V0835-75 (based on Viton{reg_sign} GLT). The outer O-ring of

  14. Desulfurizing metal with the use of nepheline ore

    Microsoft Academic Search

    S. S. Bryukhovetskii; A. A. Karpenko; Yu. V. Orobtsev; Z. Ya. Tatarinova; I. D. Podoprigora; E. B. Teplitskii; P. G. Terziyan; A. A. Tol'skii

    1978-01-01

    The ore is added to the slag during the refining period, about 20-30 min after melting of the metal. Ore consumption Varies from 120-400 kg per heat, depending on the sulfur content of the melt and the amount of added lime. Samples are taken during the heat to determine the chemical composition of the slag and metal. In all, 250,000

  15. Nanostructured Ti Consolidated via Spark Plasma Sintering

    NASA Astrophysics Data System (ADS)

    Ertorer, Osman; Topping, Troy D.; Li, Ying; Moss, Wes; Lavernia, Enrique J.

    2011-04-01

    Cryomilled nanocrystalline commercially pure (CP)-Ti powders were spark plasma sintered (SPS) using different process parameters (heating rate, temperature, pressure, and dwell time) to study densification, microstructure, and mechanical behavior. The results were rationalized on the basis of the relevant literature and experimental results, and they reveal a strong dependence on SPS parameters. An interesting finding was that the measured high ductility was accompanied by a moderate strength (yield strength [YS] = 770 MPa, ultimate tensile strength [UTS] = 840 MPa with ~27 pct elongation to failure). The combinations of microstructure and mechanical response were attributed to the multistep processing at different temperature ranges as well as to the presence of interstitial solutes.

  16. Laser Surface Treatment of Sintered Alumina

    NASA Astrophysics Data System (ADS)

    Hagemann, R.; Noelke, C.; Kaierle, S.; Wesling, V.

    Sintered alumina ceramics are used as refractory materials for industrial aluminum furnaces. In this environment the ceramic surface is in permanent contact with molten aluminum resulting in deposition of oxidic material on its surface. Consequently, a lower volume capacity as well as thermal efficiency of the furnaces follows. To reduce oxidic adherence of the ceramic material, two laser-based surface treatment processes were investigated: a powder- based single-step laser cladding and a laser surface remelting. Main objective is to achieve an improved surface quality of the ceramic material considering the industrial requirements as a high process speed.

  17. Production of reactive sintered nickel aluminide

    SciTech Connect

    Cooper, R.M.

    1993-01-01

    Effort over the past 3 months was directed at increasing manufacturing capacity (ball milling) and improving product quality. Orders for the powder have increased, mainly for plasma spray powders. NiAl is an excellent coat between a metal and a ceramic, and its use instead of cobalt should extending operating range for carbide tools. The feather phase in the sintered Ni[sub 3]Al was identified to be a Ni-rich phase nucleated on the grain boundaries with 10 wt % Al composition. The ductile to brittle temperature of powder extruded NiAl was found to be between 500 and 600 C, and shows a 50% elongation at 600 C.

  18. Iron and iron derived radicals

    SciTech Connect

    Borg, D.C.; Schaich, K.M.

    1987-04-01

    We have discussed some reactions of iron and iron-derived oxygen radicals that may be important in the production or treatment of tissue injury. Our conclusions challenge, to some extent, the usual lines of thought in this field of research. Insofar as they are born out by subsequent developments, the lessons they teach are two: Think fastexclamation Think smallexclamation In other words, think of the many fast reactions that can rapidly alter the production and fate of highly reactive intermediates, and when considering the impact of competitive reactions on such species, think how they affect the microenvironment (on the molecular scale) ''seen'' by each reactive molecule. 21 refs., 3 figs., 1 tab.

  19. Dielectric Properties and Conductivity of Iron Oxide-Barium Titanate Composites

    Microsoft Academic Search

    A. Kupreviciute; J. Banys; T. Ramoska; R. Sobiestianskas; F. M. M. Alawneh; N. Gharbi; D. C. Lupascu

    2011-01-01

    Sintered composites of iron oxide plus barium titanate in form of core-shell structures are investigated by impedance spectroscopy. The measurements were performed in the frequency and temperature ranges 20 Hz to 1 MHz and 150 K to 510 K, respectively. The composites exhibit strong low-frequency dispersion of electrical modulus and dielectric permittivity which is caused by different mechanisms of electron

  20. Genetics Home Reference: Iron-refractory iron deficiency anemia

    MedlinePLUS

    ... Genetic disorder catalog Conditions > Iron-refractory iron deficiency anemia On this page: Description Genetic changes Inheritance Diagnosis ... July 2014 What is iron-refractory iron deficiency anemia? Iron-refractory iron deficiency anemia is one of ...

  1. Breakaway frictions of dynamic O-rings in mechanical seals

    NASA Astrophysics Data System (ADS)

    Lai, Tom; Kay, Peter

    1993-05-01

    Breakaway friction of a dynamic O-ring affects the mechanical seal's response to large axial shaft movement and face wear. However, little data exist to help designers. Therefore, a test rig was developed to measure breakaway friction. The research quantitatively shows the effects of lubrication with silicone grease and a change of surface finish. By using the Taguchi statistical experimental design method, the significance of test parameters was evaluated with a minimum number of tests. It was found that fluid pressure, dwell time, and O-ring percentage squeeze affect O-ring breakaway friction more than the O-ring cross sectional diameter and axial sliding speed within the range of values tested. The authors showed that breakaway friction increased linearly with pressure. However, O-rings made of different materials had significantly different increase rates, even if they had nominally the same durometer hardness. Breakaway friction also increased with logarithm of dwell time. Again, the increase rate depended strongly on the specific O-ring material tested. These observations led the authors to believe that the typical approach of generalizing data based on generic polymer type and durometer was inappropriate.

  2. Magnetoresistance and microstructure of the sintered Ni doped Fe3O4 ferrites

    Microsoft Academic Search

    C. Y. Chou; P. C. Kuo; Y. D. Yao; A. C. Sun; S. C. Chen; I. J. Chang; J. W. Chen

    2005-01-01

    Sintered Ni doped Fe3O4 ferrites were prepared by mixing Fe3O4 powder with NiO powder and compressing into pellet, then sintering in argon atmosphere. The contents of Ni in the sintered samples were between 0 at.% and 5.08 at.%. The effects of the Ni content, sintering temperature and sintering time on the magnetoresistance (MR) and microstructure of sintered Fe3O4 ferrites were

  3. Microstructure and magnetic properties of low-temperature sintered CoTi-substituted barium ferrite for LTCC application

    NASA Astrophysics Data System (ADS)

    Chen, Daming; Liu, Yingli; Li, Yuanxun; Zhong, Wenguo; Zhang, Huaiwu

    2011-11-01

    In this article, the influences of the BaCu(B 2O 5) (BCB) additive on sintering behavior, structure and magnetic properties of iron deficient M-type barium ferrite Ba(CoTi) xFe 11.8-2 xO 19 (BaM) have been investigated. It is found that the maximum sintered densities of BaM change from 86% to 94% as the BCB content varies from 1 to 4 wt%. Single-phase BaM can be detected by the XRD analysis in the sample with 3 wt% BCB sintered at 900 °C, and the microstructure is hexagonal platelets with few intragranular pores. This is attributed to the formation of the BCB liquid phase. Meanwhile, the experimental results illuminate that the CoTi ions prefer to occupy the 4f2 and 2b sites and the magnetic properties depend on the amount of CoTi-substitution. In addition, the chemical compatibility between BaM and silver paste is also investigated; it can be seen that BaM is co-fired well with the silver paste and no other second phase is observed. Especially, the 3 wt% BCB-added Ba(CoTi) 0.9Fe 11O 19 sintered at 900 °C has good properties with the sintered density of 4.9 g/cm 3, saturation magnetization of 49.7 emu/g and coercivity of 656.6 Oe. These results indicate that it is cost effective in the production of Low Temperature Co-fired Ceramics (LTCC) multilayer devices.

  4. Influence of Binder in Iron Matrix Composites

    SciTech Connect

    Shamsuddin, S. [Faculty of Applied Science, Universiti Teknologi MARA, 02600 Arau, Perlis (Malaysia); Jamaludin, S. B. [School of Materials Engineering, Universiti Malaysia Perlis, 02600 Jejawi, Arau, Perlis (Malaysia); Hussain, Z.; Ahmad, Z. A. [School of Materials and Mineral Resources Engineering, Universiti Sains Malaysia, Seri Ampangan, 14300 Nibong Tebal, Seberang Prai Selatan, Pulau Pinang, Malaysi (Malaysia)

    2010-03-11

    The ability to use iron and its alloys as the matrix material in composite systems is of great importance because it is the most widely used metallic material with a variety of commercially available steel grades [1]. The aim of this study is to investigate the influence of binder in particulate iron based metal matrix composites. There are four types of binder that were used in this study; Stearic Acid, Gummi Arabisch, Polyvinyl alcohol 15000 MW and Polyvinyl alcohol 22000 MW. Six different weight percentage of each binder was prepared to produce the composite materials using powder metallurgy (P/M) route; consists of dry mixing, uniaxially compacting at 750 MPa and vacuum sintering at 1100 deg. C for two hours. Their characterization included a study of density, porosity, hardness and microstructure. Results indicate that MMC was affected by the binder and stearic acid as a binder produced better properties of the composite.

  5. Influence of Binder in Iron Matrix Composites

    NASA Astrophysics Data System (ADS)

    Shamsuddin, S.; Jamaludin, S. B.; Hussain, Z.; Ahmad, Z. A.

    2010-03-01

    The ability to use iron and its alloys as the matrix material in composite systems is of great importance because it is the most widely used metallic material with a variety of commercially available steel grades [1]. The aim of this study is to investigate the influence of binder in particulate iron based metal matrix composites. There are four types of binder that were used in this study; Stearic Acid, Gummi Arabisch, Polyvinyl alcohol 15000 MW and Polyvinyl alcohol 22000 MW. Six different weight percentage of each binder was prepared to produce the composite materials using powder metallurgy (P/M) route; consists of dry mixing, uniaxially compacting at 750 MPa and vacuum sintering at 1100° C for two hours. Their characterization included a study of density, porosity, hardness and microstructure. Results indicate that MMC was affected by the binder and stearic acid as a binder produced better properties of the composite.

  6. Effect of sintering temperature on the thermoelectric properties of pulse discharge sintered (Bi 0.24Sb 0.76) 2Te 3 alloy

    Microsoft Academic Search

    N. Keawprak; Z. M. Sun; H. Hashimoto; M. W. Barsoum

    2005-01-01

    P-type thermoelectric material (Bi0.24Sb0.76)2Te3 was sintered with pulse discharge sintering (PDS) process at temperatures of 345–495°C. The microstructures of sintered materials were found to be well aligned along the basal planes on the transverse direction, particularly when sintered at lower sintering temperatures. The carrier concentration was found to be higher in the transverse direction than in the longitudinal, and to

  7. IN-SITU MINING OF PHOSPHATE ORES

    SciTech Connect

    H. El-Shall; R. Stana; A. El-Midany; S. Malekzadah

    2004-12-17

    Presently the mining of Florida phosphate requires the movement of over a 100-ton of materials (overburden, sand, clay) for every ton of phosphate concentrate recovered. Not only is this energy intensive, but it also causes significant stress on the environment. In 2003, the Department of Energy solicited ideas for innovative mining ideas that could significantly improve the efficiency of mining. An award was made to the University of Florida Engineering Research Center to evaluate the in situ mining of phosphates using an aqueous CO{sub 2} solution. Tests were carried out in a 15.2 cm (6-inch) diameter column, 1.83 meter (6 feet) long at pressures up to 117.2 kg/cm{sup 2} (40 psi). Results to date demonstrate that initially the MgO is leached from the ore and then the phosphate. While the tests are continuing, so far they have not demonstrated P{sub 2}O{sub 5} concentrations that are economically attractive.

  8. Metal-sulfide mineral ores, Fenton chemistry and disease--particle induced inflammatory stress response in lung cells.

    PubMed

    Harrington, Andrea D; Smirnov, Alexander; Tsirka, Stella E; Schoonen, Martin A A

    2015-01-01

    The inhalation of mineral particulates and other earth materials, such as coal, can initiate or enhance disease in humans. Workers in occupations with high particulate exposure, such as mining, are particularly at risk. The ability of a material to generate an inflammatory stress response (ISR), a measure of particle toxicity, is a useful tool in evaluating said exposure risk. ISR is defined as the upregulation of cellular reactive oxygen species (ROS) normalized to cell viability. This study compares the ISR of A549 human lung epithelial cells after exposure to well-characterized common metal-sulfide ore mineral separates. The evaluation of the deleterious nature of ore minerals is based on a range of particle loadings (serial dilutions of 0.002m(2)/mL stock) and exposure periods (beginning at 30min and measured systematically for up to 24h). There is a wide range in ISR values generated by the ore minerals. The ISR values produced by the sphalerite samples are within the range of inert materials. Arsenopyrite generated a small ISR that was largely driven by cell death. Galena showed a similar, but more pronounced response. Copper-bearing ore minerals generated the greatest ISR, both by upregulating cellular ROS and generating substantial and sustained cell death. Chalcopyrite and bornite, both containing ferrous iron, generated the greatest ISR overall. Particles containing Fenton metals as major constituents produce the highest ISR, while other heavy metals mainly generate cell death. This study highlights the importance of evaluating the chemistry, oxidation states and structure of a material when assessing risk management. PMID:25107347

  9. An innovative method for nondestructive analysis of cast iron artifacts at Hopewell Furnace National Historic Site, Pennsylvania

    USGS Publications Warehouse

    Sloto, R.A.; Helmke, M.F.

    2011-01-01

    Iron ore containing elevated concentrations of trace metals was smelted at Hopewell Furnace during its 113 years of operation (1771-1883). For this study, we sampled iron ore, cast iron furnace products, slag, soil, groundwater, streamflow, and streambed sediment to determine the fate of trace metals released into the environment during the iron-smelting process. Standard techniques were used to sample and analyze all media except cast iron. We analyzed the trace-metal content of the cast iron using a portable X-ray fluorescence spectrometer, which provided rapid, on-site, nondestructive analyses for 23 elements. The artifacts analyzed included eight cast iron stoves, a footed pot, and a kettle in the Hopewell Furnace museum. We measured elevated concentrations of arsenic, copper, lead, and zinc in the cast iron. Lead concentrations as great as 3,150 parts per million were measured in the stoves. Cobalt was detectable but not quantifiable because of interference with iron. Our study found that arsenic, cobalt, and lead were not released to soil or slag, which could pose a significant health risk to visitors and employees. Instead, our study demonstrates these heavy metals remained with the cast iron and were removed from the site.

  10. Die attach using silver sintering practical implementation and analysis

    E-print Network

    Paris-Sud XI, Université de

    of the different implementations, and gives practical details about one of them, based on silver nano- particles are available, based on various silver particles sizes and sintering additives. This paper presents a reviewDie attach using silver sintering practical implementation and analysis Amandine Masson1 , Wissam

  11. Mineralogy and microstructure of sintered lignite coal fly ash

    Microsoft Academic Search

    Marina Ilic; Christopher Cheeseman; Christopher Sollars; Jonathan Knight

    2003-01-01

    Lignite coal fly ash from the ‘Nikola Tesla’ power plant in Yugoslavia has been characterised, milled, compacted and sintered to form monolithic ceramic materials. The effect of firing at temperatures between 1130 and 1190°C on the density, water accessible porosity, mineralogy and microstructure of sintered samples is reported. This class C fly ash has an initial average particle size of

  12. The sintering and crystallization of colloidal silica gel

    Microsoft Academic Search

    Li Hsing Wang; Bor Jou Tsai

    2000-01-01

    The isothermal kinetics of crystallization of cristobalite from silica gel at different sintering temperatures were investigated using quantitative X-ray diffraction (XRD) method. The xerogel crystallized to cristobalite and started at the surface of the glass body during sintering at 1100°C in a He atmosphere. If the xerogel was treated with CCl4, the nucleation and growth processes determined the crystallization during

  13. Microwave sintering of the high-? superconductor Y - Ba - Cu - O

    Microsoft Academic Search

    A. Cherradi; S. Marinel; G. Desgardin; J. Provost; B. Raveau

    1997-01-01

    Use of microwave energy to produce high temperatures for sintering ceramics, especially superconductors, appears to be a technique of great interest. Here, new results are presented dealing with the sintering of high- superconducting Y - Ba - Cu - O samples in a TE102 microwave cavity. It is demonstrated that heating is mainly governed by magnetic induction. A good understanding

  14. Consolidation of amorphous oxide powders using spark plasma sintering

    Microsoft Academic Search

    Daniela Marisa Fredrick

    2009-01-01

    The objective of this study is to synthesize amorphous oxide powders and sinter the systems close to or at theoretical density for optical transparency while retaining the amorphous structure using the Spark Plasma Sintering (SPS) method. In addition, the parameters that govern the formation of these systems were investigated. The main powder processing techniques are sol-gel, flame-spaying and spherodizing. The

  15. Simulation of microwave sintering of ceramic bodies with complex geometry

    Microsoft Academic Search

    A. Birnboim; Y. Carmel

    1999-01-01

    Summary form only given. Microwave sintering is an emerging technology in which the energy is directly applied to the material enabling fast sintering with a potential for synthesis of advanced ceramic materials with superior properties. A dynamic balance between the rate of electromagnetic energy absorbed within the bulk of the sample and the rate of energy loss from its surface

  16. Direct metal laser sintering: a digitised metal casting technology.

    PubMed

    Venkatesh, K Vijay; Nandini, V Vidyashree

    2013-12-01

    Dental technology is undergoing advancements at a fast pace and technology is being imported from various other fields. One such imported technology is direct metal laser sintering technology for casting metal crowns. This article will discuss the process of laser sintering for making metal crowns and fixed partial dentures with a understanding of their pros and cons. PMID:24431766

  17. Preparation of translucent YAG:Ce ceramics by reaction sintering

    Microsoft Academic Search

    D Michalik; M Sopicka-Lizer; T Pawlik; J Chrapo?ski

    2012-01-01

    The paper presents preparation of YAG precursor powders mixture with ability for the reaction sintering at lower temperature. The powder mixture was mechanochemically processed and characterized for the specific surface area and crystallinity (XRD). Sintering experiments were performed on the batched powders, mechanochemically processed powders and as-synthesised YAG powders. XRD measurements and SEM\\/TEM studies were applied for characterization of the

  18. CALCIUM OXIDE SINTERING IN ATMOSPHERES CONTAINING WATER AND CARBON DIOXIDE

    EPA Science Inventory

    The paper gives results of measurements of the effects of water vapor and CO2 on the sintering rate of nascent CaO, as a function of partial pressure and temperature using CaO prepared by rapid decomposition of CaCO3 and CA(OH)2. Each gas strongly catalyzed the sintering process ...

  19. Subsurface Crack Propagation in Rolling Contact Fatigue of Sintered Alloy

    Microsoft Academic Search

    Yukio Miyashita; Yoshihiro Yoshimura; Jin-Quan Xu; Makoto Horikoshi; Yoshiharu Mutoh

    2003-01-01

    Rolling contact fatigue tests of sintered alloy were carried out under two cylinder contacts. Damage of the specimen was detected by using acceleration sensor before occurrence of final failure, namely spalling failure. In order to study the damage process of contact fatigue of sintered alloy, surfaces and cross sections of the specimens were observed after contact fatigue test. Damage on

  20. Method for sintering fuel cell electrodes using a carrier

    DOEpatents

    Donelson, R.; Bryson, E.S.

    1995-03-28

    A carrier is described for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a carbon-based paint, the carbon-based paint comprising an organic binder. The carbon-based paint may be an alcohol or a solvent-based paint or a water-based paint.

  1. Coated metal sintering carriers for fuel cell electrodes

    DOEpatents

    Donelson, Richard (Glen Waverly, AU); Bryson, E. S. (Downers Grove, IL)

    1998-01-01

    A carrier for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a water-based carbon paint, the water-based carbon paint comprising water, powdered graphite, an organic binder, a wetting agent, a dispersing agent and a defoaming agent.

  2. Method for sintering fuel cell electrodes using a carrier

    DOEpatents

    Donelson, Richard (Victoria, AU); Bryson, E. S. (Downers Grove, IL)

    1995-01-01

    A carrier for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a carbon-based paint, the carbon-based paint comprising an organic binder. The carbon-based paint may be an alcohol or a solvent-based paint or a water-based paint.

  3. Coated metal sintering carriers for fuel cell electrodes

    DOEpatents

    Donelson, R.; Bryson, E.S.

    1998-11-10

    A carrier is described for conveying components of a fuel cell to be sintered through a sintering furnace. The carrier comprises a metal sheet coated with a water-based carbon paint, the water-based carbon paint comprising water, powdered graphite, an organic binder, a wetting agent, a dispersing agent and a defoaming agent.

  4. Optimizing of selective laser sintering method

    SciTech Connect

    Guo Suiyan [Beijing Long Yuan Automatic Fabrication System Co. Ltd. (China)

    1996-12-31

    In a SLS process, a computer-controlled laser scanner moves laser beam spot on flat powder bed and the laser beam heat the powder to cause sintering in the specific area. A series of such flat planes is linked together to construct a 3D object. SLS is a complex process which involves many process parameters. The laser beam properties, such as laser beam profile, intensity, and wave length, as well as its scanning speed and scanning path, are very important parameters. Laser properties, powder properties and sintering environment work together in a SLS process to determine whether SLS is successful. The objective of SLS is to make a part which has the same size as the CAD data. The accuracy of the final part from SLS is affected by a lot of parameters as mentioned above. How to control these parameters is a key to produce an acceptable final part. Laser parameters, powder material properties and processing environment can all affect the quality of SLS part. A lot of effort has been made in parametric analysis, material properties and processing environment for SLS by other researchers. The focus of this paper is to optimize laser parameters and scanning path to improve quality of SLS part and the processing speed. A scanning method is discussed to improve the quality and speed together.

  5. Serpentinization of sintered olivine during seawater percolation experiments

    NASA Astrophysics Data System (ADS)

    Luquot, Linda; Andreani, Muriel; Godard, Marguerite; Gouze, Philippe; Gibert, Benoit

    2010-05-01

    Hydration of the mantle lithosphere exposed along detachment faults at slow-spreading ridges leads to strong modification of rock rheological, geophysical and geochemical properties, and to the emission of large amounts of H2 and CH4, and of complex carbon molecules that support primitive ecosystems. The sustainability and efficiency of this hydration process, serpentinisation, and of associated reactions, requires penetration and renewal of fluids at the mineral-fluid interface. However, precipitation of material along flow paths will affect porosity and permeability that, in turn, will have feedbacks effects on the reactions. It is thus necessary to investigate the sustainability of flow paths, and the evolution of reaction rates for a dynamic system under representative conditions. We investigate these processes by percolation experiments carried out under P, T representative conditions, using the ICARE Microlab experimental bench. We present the preliminary results of seawater percolation within samples of sintered San Carlos olivine. The experiments were carried out under a confined pressure of 190 bars and a temperature of 190° C and water flow was set at a constant specific discharge of 0.06 ml/h.. The experiments were performed at very slow flow rate to be more representative of natural systems. ICARE Microlab allows measuring continuously the permeability changes during the percolation experiment and sampling the brine at the outlet of the sample. After 20 days of experiments, poorly crystallized serpentine and iron oxide formed within the micro-cracks while permeability strongly decreases. Such rapid precipitation of serpentine results in clogging of fluid paths. The chemical composition of the outlet fluid is dominated by Si and is depleted in Mg relative to stoechiometric dissolution of olivine during the whole experiment suggesting that brucite possibly formed. SEM and AEM/TEM are used to characterize the reactive interfaces and the neoformed materials.

  6. Thermal evolution and sintering of chondritic planetesimals

    NASA Astrophysics Data System (ADS)

    Henke, S.; Gail, H.-P.; Trieloff, M.; Schwarz, W. H.; Kleine, T.

    2012-01-01

    Aims: Radiometric ages for chondritic meteorites and their components provide information on the accretion timescale of chondrite parent bodies, and on cooling paths within certain areas of these bodies. However, to use this age information for constraining the internal structure, and the accretion and cooling history of the chondrite parent bodies, the empirical cooling paths obtained by dating chondrites must be combined with theoretical models of the thermal evolution of planetesimals. Important parameters in such thermal models include the initial abundances of heat-producing short-lived radionuclides (26Al and 60Fe), which are determined by the accretion timescale and the terminal size, chemical composition and physical properties of the chondritic planetesimals. The major aim of this study is to assess the effects of sintering of initially porous material on the thermal evolution of planetesimals, and to constrain the values of basic parameters that determined the structure and evolution of the H chondrite parent body. Methods: We present a new code for modelling the thermal evolution of ordinary chondrite parent bodies that initially are highly porous and undergo sintering by hot pressing as they are heated by decay of radioactive nuclei. The pressure and temperature stratification in the interior of the bodies was calculated by solving the equations of hydrostatic equilibrium and energy transport. The decrease of porosity of the granular material by hot pressing due to self-gravity was followed by solving a set of equations for the sintering of powder materials. For the heat-conductivity of granular material we combined recently measured data for highly porous powder materials, relevant for the surface layers of planetesimals, with data for heat-conductivity of chondrite material, relevant for the strongly sintered material in deeper layers. Results: Our new model demonstrates that in initially porous planetesimals heating to central temperatures sufficient for melting can occur for bodies a few km in size, that is, a factor of ?10 smaller than for compact bodies. Furthermore, for high initial 60Fe abundances small bodies may differentiate even when they had formed as late as 3-4 Ma after CAI formation. To demonstrate the capability of our new model, the thermal evolution of the H chondrite parent body was reconstructed. The model starts with a porous body that is later compacted first by "cold pressing" at low temperatures and then by "hot pressing" for temperatures above ?700 K, i.e., the threshold temperature for sintering of silicates. The thermal model was fitted to the well-constrained cooling histories of the two H chondrites Kernouvé (H6) and Richardton (H5). The best fit was obtained for a parent body with a radius of 100 km that accreted at t = 2.3 Ma after CAI formation, and had an initial 60Fe/56Fe = 4.1 × 10-7. Burial depths of 8.3 km and 36 km for Richardton and Kernouvé were able to reproduce their empirically determined cooling history. These burial depths are shallower than those derived in previous models. This reflects the strong insulating effect of the residual powder surface layer, which is characterised by a low thermal conductivity.

  7. 2D and 3D SIMS investigations on sintered steels

    NASA Astrophysics Data System (ADS)

    Krecar, Dragan; Zwanziger, Jürgen; Vassileva, Vassilka; Danninger, Herbert; Hutter, Herbert

    2005-09-01

    Powder metallurgy (PM) is a well-established method for manufacturing ferrous precision parts. Sintering is one of the important production steps and can be strongly enhanced (activated) by formation of a liquid phase during the sintering process. The liquid phase can be reached by the addition of alloying elements (e.g., copper) or sintering activators (e.g., phosphorus) and is formed by melting of eutectic phase mixtures or by incipient melting. The main investigations presented in this work are done by secondary ion mass spectrometry (SIMS): 2D and 3D elemental distribution. Additionally, impact energy and hardness measurements were performed in order to study the influence of phosphorus on mechanical properties. The concentration of P in different samples was varied between 0 and 1 weight percent (wt.%), the carbon content was consistently 0.5 wt.%. Nominal specimens were sintered at 1120 and 1250 °C in protective atmosphere of flowing nitrogen to determine the influence of sintering temperature.

  8. Pyrolysis-gas chromatography of carbonate apatites used for sintering.

    PubMed

    Doi, Y; Koda, T; Adachi, M; Wakamatsu, N; Goto, T; Kamemizu, H; Moriwaki, Y; Suwa, Y

    1995-11-01

    Gas chromatography was employed to quasi-continuously determine the amount of carbon dioxide that evolved from carbonate apatite specimens during sintering. Assuming that the carbonate in the specimens decomposed to carbon dioxide on a mole-for-mole basis, the determination of the carbon dioxide evolved allowed for the determination of the amount of carbonate that remained in the specimens during different stages of sintering. Previously, this measurement could be carried out only after sintering was completed. Comparison of data obtained from specimens compacted isostatically at 600 MPa for sintering with powder specimens indicated that the amount of carbonate remaining in the sintered apatite mass strongly depended on heating rates, heating temperatures, and holding-time intervals. PMID:8582914

  9. A Combined Statistical-Microstructural Model for Simulation of Sintering

    SciTech Connect

    BRAGINSKY,MICHAEL V.; DEHOFF,ROBERT T.; OLEVSKY,EUGENE A.; TIKARE,VEENA

    1999-10-22

    Sintering theory has been developed either as the application of complex diffusion mechanisms to a simple geometry or as the deformation and shrinkage of a continuum body. They present a model that can treat in detail both the evolution of microstructure and the sintering mechanisms, on the mesoscale, so that constitutive equations with detail microstructural information can be generated. The model is capable of simulating vacancy diffusion by grain boundary diffusion, annihilation of vacancies at grain boundaries resulting in densification, and coarsening of the microstructural features. In this paper, they review the stereological theory of sintering and its application to microstructural evolution and the diffusion mechanism, which lead to sintering. They then demonstrate how these stereological concepts and diffusion mechanisms were incorporated into a kinetic Monte Carlo model to simulate sintering. Finally, they discuss the limitations of this model.

  10. Sintering and redispersion of platinum in reforming catalyst

    SciTech Connect

    Yaofang Liu; Guoqing Pan; Guanghua Yang [Univ. of Petroleum, Beijing (China)

    1995-12-31

    Platinum sintering and redispersion were systematically investigated with PtRe and PtSn reforming catalysts. It was found that platinum might sinter both in catalyst dehydration for exsiccation during start-of-run and in coke burning during regeneration and had the same sintering mechanism as the followings PtO{sub 2}{r_reversible}Pt+O{sub 2}, except melt of alumina supporter. The sintered platinum could be completely redispersed through regeneration if the alumina had no decrease in its surface area. Otherwise the loss in the platinum dispersion or dehydrogenation activity of the catalyst after regeneration would be proportional to the loss in surface area of alumina. The sintered platinum redispersed quite fast, taking about 10 minutes of chlorination and 30 minutes of oxidation.

  11. Application of geostatistical techniques for evaluation of the reserves of an iron mines using geophysical and geological data

    NASA Astrophysics Data System (ADS)

    Noh, M.; Seokhoon, O.

    2013-12-01

    We performed 3-D geostatistical ore modeling for evaluation of an iron mining deposit using geophysical data((electrical resistivity, MT) and geological data (borehole data, geology data, physical properties of core). MT data were acquired at 50 stations and electrical resistivity data were obtained for 9 lines. Borehole data obtained between 1960~2013's were used to identify rock types and to analyze grade. We performed a correlation analysis on the electrical resistivity and grade using physical properties of cores. As a result, decrease in electrical resistivity values showed the increase of the grade of ore. In this study, a variety of geostatistical techniques are applied to estimate the grade of ore for the study area. The SGS(Sequential Gaussian Simulation)method of geostatistical techniques for the integrated data analysis was applied to study area using electrical resistivity data and MT data. The simulation results showed the electrical resistivity distribution in the study area. And To make an ore model based on the geostatistical modeling, indicator simulation was performed with index value depending on rock type. Through the results, the distribution of ore is illuminated and some location with high grade ore is known as in Figure 1. Figure 1. The result of SGS of geostatistical techniques in ore body model.

  12. Fluorosilicone and silicone o-ring aging study.

    SciTech Connect

    Bernstein, Robert; Gillen, Kenneth T.

    2007-10-01

    Fluorosilicone o-ring aging studies were performed. These studies examined the compressive force loss of fluorosilicone o-rings at accelerated (elevated) temperatures and were then used to make predictions about force loss at room temperature. The results were non-Arrhenius with evidence for a lowering in Arrhenius activation energies as the aging temperature was reduced. The compression set of these fluorosilicone o-rings was found to have a reasonably linear correlation with the force loss. The aging predictions based on using the observed curvature of the Arrhenius aging plots were validated by field aged o-rings that yielded degradation values reasonably close to the predictions. Compression set studies of silicone o-rings from a previous study resulted in good correlation to the force loss predictions for the fluorosilicone o-rings from this study. This resulted in a preliminary conclusion that an approximately linear correlation exists between compression set and force decay values for typical fluorosilicone and silicone materials, and that the two materials age at similar rates at low temperatures. Interestingly, because of the observed curvature of the Arrhenius plots available from longer-term, lower temperature accelerated exposures, both materials had faster force decay curves (and correspondingly faster buildup of compression set) at room temperature than anticipated from typical high-temperature exposures. A brief study on heavily filled conducting silicone o-rings resulted in data that deviated from the linear relationship, implying that a degree of caution must be exercised about any general statement relating force decay and compression set.

  13. Seismic 3D full waveform response of Outokumpu type ore

    NASA Astrophysics Data System (ADS)

    Komminaho, Kari; Hellqvist, Niina; Tuomi, Hilkka; Koivisto, Emilia; Heinonen, Suvi; Heikkinen, Pekka

    2015-04-01

    Outokumpu assemblage (or Outokumpu association) means a regular occurrence of quartzites, skarns and carbonate rocks around serpentinite bodies. The core is serpentine and from there outwards deposit changes to, in this order, carbonate bearing serpentinite to carbonate rock to tremolite skarn to diopside skarn and to quartzite. The ore bodies are hosted by the Outokumpu assemblage and occur on the fringes of the serpentinized peridotites. The Cu-Co-Zn ores form massive or semi-massive sulfide bodies of approx. 10-20 m thickness. In the north-western part of Outokumpu area is a formation of Proterozoic cover sediments and Archaean basement rocks out-cropping about 2 km to northwest from the end of line V7 in the Saarivaara area. These rocks have felsic and mafic lithologies and show good reflectivity. Recent shallow drilling has revealed rapidly alternating 5-50 meters thick layers of Archaean granite gneiss, as well as Proterozoic quartzite, metadiabase, and calc-silicate rocks. In this study the seismic signatures of Outokumpu type ore is calculated in two different host environments: (A) hosted by Outokumpu assemblage within mica schist and (B) in the presence Proterozoic-Archaean rocks. The long history of the Outokumpu ore belt has produced a massive geological and geophysical knowledge base of the district. A 3D geological model is used as a basis, with some simplifications, for seismic full waveform modeling. Elastic finite-difference modeling (SOFI3D/2D) results are presented. Modeling results shows very strong reflective signatures from host rock environment of the deposits compared to surrounding rocks and can be followed through modeled sections. The Outokumpu type massive ore has a strong reflection contrast even to hosting rocks. Reflection/diffraction patterns as well converted phases originating directly from a theoretical ore inclusion are calculated. Modeling results are compared to the real existing high resolution seismic reflection profiles in Outokumpu area (HIRE; HIgh REsolution reflection seismics for ore exploration, 2007-2010 profiles).

  14. Magnetic properties and loss separation in iron powder soft magnetic composite materials

    NASA Astrophysics Data System (ADS)

    De Wulf, Marc; Anestiev, Ljubomir; Dupré, Luc; Froyen, Ludo; Melkebeek, Jan

    2002-05-01

    New developments in powder metallurgical composites make soft magnetic composite (SMC) material interesting for application in electrical machines, when combined with new machine design rules and new production techniques. In order to establish these design rules, one must pay attention to electromagnetic loss characteristics of SMC material. In this work, five different series of iron based SMCs are produced and studied: (1) Pure iron powder with resin; (2) sintered iron based powders; (3) pure iron powder with additions of Zn-st and carbon; (4) iron based powder alloys (Fe,Nb,Si); (5) commercially available iron powder "Somaloy." The specimens were shaped as rectangular rods and characterized on a miniature single sheet tester which was calibrated to Epstein. The measured energy losses are analyzed following the loss separation theory of Bertotti, in which the total energy loss is decomposed into hysteresis loss, classical Foucault loss, and an excess loss component.

  15. Pharmacology of Iron Transport

    PubMed Central

    Byrne, Shaina L.; Krishnamurthy, Divya; Wessling-Resnick, Marianne

    2013-01-01

    Elucidating the molecular basis for the regulation of iron uptake, storage, and distribution is necessary to understand iron homeostasis. Pharmacological tools are emerging to identify and distinguish among different iron transport pathways. Stimulatory or inhibitory small molecules with effects on iron uptake can help characterize the mechanistic elements of iron transport and the roles of the transporters involved in these processes. In particular, iron chelators can serve as potential pharmacological tools to alleviate diseases of iron overload. This review focuses on the pharmacology of iron transport, introducing iron transport membrane proteins and known inhibitors. PMID:23020294

  16. The Sintering, Sintered Microstructure and Mechanical Properties of Ti-Fe-Si Alloys

    NASA Astrophysics Data System (ADS)

    Yang, Y. F.; Luo, S. D.; Schaffer, G. B.; Qian, M.

    2012-12-01

    A systematic study has been conducted of the sintering, sintered microstructure and tensile properties of a range of lower cost Ti-Fe-Si alloys, including Ti-3Fe-(0-4)Si, Ti-(3-6)Fe-0.5Si, and Ti-(3-6)Fe-1Si (in wt pct throughout). Small additions of Si (?1 pct) noticeably improve the as-sintered tensile properties of Ti-3Fe alloy, including the ductility, with fine titanium silicides (Ti5Si3) being dispersed in both the ? and ? phases. Conversely, additions of >1 pct Si produce coarse and/or networked Ti5Si3 silicides along the grain boundaries leading to predominantly intergranular fracture and, hence, poor ductility, although the tensile strength continues to increase because of the reinforcement by Ti5Si3. Increasing the Fe content in the Ti- xFe-0.5/1.0Si alloys above 3 pct markedly increases the average grain size and changes the morphology of the ?-phase phase to much thinner and more acicular laths. Consequently, the ductility drops to <1 pct. Si reacts exothermically with Fe to form Fe-Si compounds prior to the complete diffusion of the Fe into the Ti matrix during heating. The heat thus released in conjunction with the continuous external heat input melts the silicides leading to transient liquid formation, which improves the densification during heating. No Ti-TiFe eutectoid was observed in the as-sintered Ti-Fe-Si alloys. The optimum PM Ti-Fe-Si compositions are determined to be Ti-3Fe-(0.5-1.0)Si.

  17. Sintered ceramic body containing titanium carbonitride

    SciTech Connect

    Watanabe, T.; Enomoto, Y.; Tsuya, Y.

    1985-01-08

    A refractory ceramic body having excellent bending strength and high hardness and with little porosity is obtained by sintering a powdery mixture comprising 5 to 95% by weight of a titanium carbonitride and 95 to 5% by weight of a metal boride such as metal diborides, e.g. titanium diboride, W/sub 2/B/sub 5/ and Mo/sub 2/B/sub 5/ at a temperature of 1700/sup 0/ to 1800/sup 0/ C. Further improvements can be obtained by partial replacement of the above mentioned components with elementary boron, titanium carbide or titanium nitride or when the titanium carbonitride component is a combination of at least two kinds of titanium carbonitrides having different chemical compositions relative to the proportion of the carbon and nitrogen.

  18. Method of manufacturing iron aluminide by thermomechanical processing of elemental powders

    DOEpatents

    Deevi, Seetharama C. (Midlothian, VA); Lilly, Jr., A. Clifton (Chesterfield, VA); Sikka, Vinod K. (Oak Ridge, TN); Hajaligol, Mohammed R. (Richmond, VA)

    2000-01-01

    A powder metallurgical process of preparing iron aluminide useful as electrical resistance heating elements having improved room temperature ductility, electrical resistivity, cyclic fatigue resistance, high temperature oxidation resistance, low and high temperature strength, and/or resistance to high temperature sagging. The iron aluminide has an entirely ferritic microstructure which is free of austenite and can include, in weight %, 20 to 32% Al, and optional additions such as .ltoreq.1% Cr, .gtoreq.05% Zr or ZrO.sub.2 stringers extending perpendicular to an exposed surface of the heating element, .ltoreq.2% Ti, .ltoreq.2% Mo, .ltoreq.1% Zr, .ltoreq.1% C, .ltoreq.0.1% B, .ltoreq.30% oxide dispersoid and/or electrically insulating or electrically conductive covalent ceramic particles, .ltoreq.1 % rare earth metal, .ltoreq.1% oxygen, and/or .ltoreq.3% Cu. The process includes forming a mixture of aluminum powder and iron powder, shaping the mixture into an article such as by cold rolling the mixture into a sheet, and sintering the article at a temperature sufficient to react the iron and aluminum powders and form iron aluminide. The sintering can be followed by hot or cold rolling to reduce porosity created during the sintering step and optional annealing steps in a vacuum or inert atmosphere.

  19. Sintering dense NiZn ferrite by two-step sintering process

    SciTech Connect

    Su Hua; Tang Xiaoli; Zhang Huaiwu; Zhong Zhiyong; Shen Jian [State Key Laboratory of Electronic Thin Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu 610054 (China)

    2011-04-01

    A two-step sintering process has been adopted to produce NiZn ferrite with composition of (NiO){sub 0.35}(ZnO){sub 0.57}(CuO){sub 0.08}(Fe{sub 2}O{sub 3}). The densification, microstructure, and magnetic properties of the ferrite have been investigated and compared with those of ferrites produced by the traditional final-stage sintering process. It was found that the sample produced by a two-step sintering process with a high temperature of 1200 deg. C and a lower temperature of 1100 deg. C attained more than 96% of the theoretical density and had a uniform microstructure with a small average grain size. It also exhibited good performances in terms of permeability and Q-factor. Hence, this would seem to be an effective method for producing dense ferrites with a microstructure composed of small and even grains, which is a very effective strategy for improving the magnetic properties of ferrites.

  20. A comparison of the sintering of various titanium powders

    SciTech Connect

    Gerdemann, Stephen J.; Alman, David E.

    2005-02-01

    Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press- and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350°C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics; with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

  1. Temperature gradients and residual porosity in microwave sintered zinc oxide

    SciTech Connect

    Martin, L.P.; Dadon, D.; Rosen, M. [Johns Hopkins Univ., Baltimore, MD (United States). Dept. of Materials Science and Engineering; Birman, A.; Gershon, D.; Calame, J.P.; Levush, B.; Carmel, Y. [Univ. of Maryland, College Park, MD (United States). Lab. for Plasma Research

    1996-12-31

    ZnO samples were sintered in an overmoded 2.45 GHz microwave applicator. In-situ differential temperature measurements were made to allow comparison of surface and core temperatures during heating. At intermediate temperatures, near 600 C, the sample core was measured to be more than 250 C hotter than the sample surface. As the core temperature approached 1,100 C, however, the difference between the surface and core temperatures diminished. Post-sintering scanning electron microscopy (SEM) showed spatial variations in the residual porosity which were consistent with the measured temperature differential. For samples sintered to intermediate temperatures, where large temperature differences persisted, there were significant gradients in the residual porosity. For samples sintered to higher temperatures, there was little residual porosity and no observable porosity gradient. Local density versus temperature behavior was obtained by correlating porosity levels measured from the micrographs with temperature measurements made during sintering. These data demonstrate a significantly lower activation energy for microwave sintering than for conventional sintering.

  2. Aggregate Morphology Evolution by Sintering: Number & Diameter of Primary Particles.

    PubMed

    Eggersdorfer, Max L; Kadau, Dirk; Herrmann, Hans J; Pratsinis, Sotiris E

    2012-04-01

    The structure of fractal-like agglomerates (physically-bonded) and aggregates (chemically- or sinter-bonded) is important in aerosol synthesis of nanoparticles, and in monitoring combustion emissions and atmospheric particles. It influences also particle mobility, scattering, and eventually performance of nanocomposites, suspensions and devices made with such particles. Here, aggregate sintering by viscous flow of amorphous materials (silica, polymers) and grain boundary diffusion of crystalline ceramics (titania, alumina) or metals (Ni, Fe, Ag etc.) is investigated. A scaling law is found between average aggregate projected area and equivalent number of constituent primary particles during sintering: from fractal-like agglomerates to aggregates and eventually compact particles (e.g. spheres). This is essentially a relation independent of time, material properties and sintering mechanisms. It is used to estimate the equivalent primary particle diameter and number in aggregates. The evolution of aggregate morphology or structure is quantified by the effective fractal dimension (Df ) and mass-mobility exponent (Dfm ) and the corresponding prefactors. The Dfm increases monotonically during sintering converging to 3 for a compact particle. Therefore Dfm and its prefactor could be used to gauge the degree or extent of sintering of agglomerates made by a known collision mechanism. This analysis is exemplified by comparison to experiments of silver nanoparticle aggregates sintered at different temperatures in an electric tube furnace. PMID:23658467

  3. Hydroxyapatite-coated metals: interfacial reactions during sintering.

    PubMed

    Wei, M; Ruys, A J; Swain, M V; Milthorpe, B K; Sorrell, C C

    2005-02-01

    Electrophoretic deposition (EPD) is a low cost flexible process for producing HA coatings on metal implants. Its main limitation is that it requires heating the coated implant in order to densify the HA. HA typically sinters at a temperature below 1150 degrees C, but metal implants are degraded above 1000 degrees C. Further, the metal induces the decomposition of the HA coating upon sintering. Recent developments have enabled EPD of metathesis-synthesised uncalcined HA which sinters at approximately 1000 degrees C. The effects of temperature on HA-coated Ti, Ti6Al4V, and 316L stainless steel were investigated for dual coatings of metathesis HA sintered at 1000 degrees C. The use of dual HA coatings (coat, sinter, coat, sinter) enabled decomposition to be confined to the "undercoat" (HA layer 1), with the surface coating decomposition free. The tensile strength of the three metals was not significantly affected by the high sintering temperatures (925 degrees C < T < 1000 degrees C). XRD/SEM/EDS analyses of the interfacial zones revealed that 316L had a negligible HA:metal interfacial zone (approximately 1 microm) while HA:Ti and HA:Ti6Al4V had large interfacial zones (>10 microm) comprising a TiO2 oxidation zone and a CaTiO2 reaction zone. PMID:15744597

  4. Influence of MâCâ carbides orientation on the wear resistance of 300Kh20DNF white iron

    Microsoft Academic Search

    I. I. Tsypin; V. I. Kantorovich; A. D. Zuev

    1992-01-01

    This research examined the carbides distribution effect relative to the working surface, on the wear of o-ring seals fabricated from 300kh20DNF iron. Wear in the rings was determined with the carbides distributed parallel and perpindicular to th working surface, and in the nonorientated condition.

  5. A STUDY on the OPTIMUM CONDITIONS of the CEMENTATION of COPPER in CHLORINATION SOLUTION of CHALCOPYRITE CONCENTRATE by IRON SCRAPS

    Microsoft Academic Search

    Hakan TEMUR; M. Muhtar KOCAKERIM

    Present study aims an experimental design based on the approach of Taguchi method to optimize of cementation of copper in chlorination solutions of chalcopyrite concentrate neutralized with oxidized copper ore by iron scraps. The concentrations of Fe3+, Cu2+, H+, SO4 2- and Cl- ions in the chlorination solution obtained

  6. Microstructure of Laser-MAG Hybrid Welds of Sintered P/M Steel

    NASA Astrophysics Data System (ADS)

    Liu, Shuangyu; Zhang, Hong; Hu, Jiandong; Shi, Yan

    2013-01-01

    The microstructure and mechanical properties of iron-based powder metallurgical steels jointed by CO2 laser-metal active gas (MAG) hybrid welding were investigated. The cross-sectional morphology of hybrid weld bead consisted of arc zone and laser zone. The microstructure of arc zone consisted of columnar dendrite and fine acicular dendrite between the columnar dendrites, but that of laser zone was composed of fine equiaxed dendrite. The MAG weld had obvious heat-affected zone (HAZ) zone, while hybrid weld had very narrow HAZ zone because of the rapid cooling rate. The phase constitutions of the joint determined by x-ray diffraction were ?-Fe (ferrite) and Cu. The 2? value of ?-Fe (200) peaks of hybrid weld was smaller than that of sintering compact. Compared to MAG weld, hybrid weld had finer grain size, higher micro-hardness, and higher micro-strain, which was caused by the difference of cooling rate and crystallizing.

  7. Effect of copper on the properties of Pr-Dy-Fe-Co-B sintered magnets

    NASA Astrophysics Data System (ADS)

    Kablov, E. N.; Piskorskii, V. P.; Valeev, R. A.; Volkov, N. V.; Davydova, E. A.; Shaikhutdinov, K. A.; Balaev, D. A.; Semenov, S. V.

    2014-01-01

    The effect of copper on the properties of magnets (Pr0.52Dy0.48)13(Fe65Co0.35)80.3 - x Cu x B6.7 ( x = 0-10) has been studied. Alloying with copper is shown to decrease the sintering temperature and to increase the content of the principal (Pr,Dy)2(Fe,Co)14B magnetic phase. For compositions with x = 1.3-3.3, copper is found to affect the value and sign of the temperature induction coefficient (TIC). It is shown that the effect of copper on the TIC is determined by the substitution of copper ions for iron ions in lattice sites, which are coupled via an antiferromagnetic exchange interaction.

  8. Iron and Prochlorococcus/

    E-print Network

    Thompson, Anne Williford

    2009-01-01

    Iron availability and primary productivity in the oceans are intricately linked through photosynthesis. At the global scale we understand how iron addition induces phytoplankton blooms through meso-scale iron-addition ...

  9. Iron deficiency anemia

    MedlinePLUS

    Anemia - iron deficiency ... Iron deficiency anemia is the most common form of anemia. Red blood cells bring oxygen to the ... such as your spleen, remove old blood cells. Iron is a key part of red blood cells. ...

  10. Spark Plasma Sintering of Fuel Cermets for Nuclear Reactor Applications

    SciTech Connect

    Yang Zhong; Robert C. O'Brien; Steven D. Howe; Nathan D. Jerred; Kristopher Schwinn; Laura Sudderth; Joshua Hundley

    2011-11-01

    The feasibility of the fabrication of tungsten based nuclear fuel cermets via Spark Plasma Sintering (SPS) is investigated in this work. CeO2 is used to simulate fuel loadings of UO2 or Mixed-Oxide (MOX) fuels within tungsten-based cermets due to the similar properties of these materials. This study shows that after a short time sintering, greater than 90 % density can be achieved, which is suitable to possess good strength as well as the ability to contain fission products. The mechanical properties and the densities of the samples are also investigated as functions of the applied pressures during the sintering.

  11. A new sintering aid for magnesium aluminate spinel

    Microsoft Academic Search

    I Ganesh; S Bhattacharjee; B. P Saha; R Johnson; Y. R Mahajan

    2001-01-01

    A dense MgAl2O4 sintered spinel has been prepared following a conventional double stage firing process. A new type of sintering aid, AlCl3, can improve the bulk density, apparent porosity and water absorption of MgAl2O4 spinel sintered at 1550°C devoid of any contamination. In order to see the effect of AlCl3 on densification and formation of a MgAl2O4 spinel, 0.01–0.03 mol%

  12. Effects of various additives on sintering of aluminum nitride

    NASA Technical Reports Server (NTRS)

    Komeya, K.; Inoue, H.; Tsuge, A.

    1982-01-01

    Effects of thirty additives on sintering A/N were investigated. The addition of alkali earth oxides and rare earth oxides gave fully densified aluminum nitride. This is due to the formation of nitrogen-containing aluminate liquid in the system aluminum nitride-alkali earth oxides or rare earth oxides. Microstructural studies of the sintered specimens with the above two types of additives suggested that the densification was due to the liquid phase sintering. Additions of silicon compounds resulted in poor densification by the formation of highly refractory compounds such as A/N polytypes.

  13. Microwave reaction sintering of tungsten carbide cobalt hardmetals

    SciTech Connect

    Gerdes, T.; Willert-Porada, M. [Univ. of Dortmund (Germany). Dept. Chemical Engineering; Roediger, K.; Dreyer, K. [WIDIA GmbH, Essen (Germany)

    1996-12-31

    Microwave reaction sintering of tungsten- carbon-, cobalt mixtures is described as a method that combines the liquid phase reaction sintering of tungsten carbide cobalt hardmetals with the enhanced densification behavior of hardmetals in the microwave field. Starting with green parts composed of W-, Co- powder, soot as carbon source and with varying amount of additives a dense and extremely fine grained hardmetal can be obtained in one pressureless microwave reaction sintering step. By this method hardmetals with improved mechanical properties can be obtained in a drastically simplified processing cycle, without time consuming steps such as carburizing and milling.

  14. Preparation of zirconia transparent ceramics by low temperature microwave sintering.

    PubMed

    Luo, Junming; Tu, Haiqing; Deng, Liping; Zhong, Zhenchen

    2014-05-01

    Nanocrystalline yttria-stabilized zirconia (ZrO2-8 mol%Y2O3, 8YSZ) was synthesized by a homogeneous precipitation process using urea as the precipitation agent. Zirconia (ZrO2) transparent ceramics samples have been successfully fabricated by a microwave sintering process at low temperature. The technologies of low-temperature microwave sintering and the relationships of the microstructures and properties of the specified samples have been investigated in detail. We have found out that the low-temperature microwave sintering has its obvious advantages over the other methods in manufacturing zirconia transparent ceramics. PMID:24734674

  15. Densification of nanocrystalline ITO powders in fast firing: effect of specimen mass and sintering atmosphere

    Microsoft Academic Search

    Bong-Chull Kim; Joon-Hyung Lee; Jeong-Joo. Kim; Hee Young Lee; Jai-Sung Lee

    2005-01-01

    Nano-sized indium tin oxide (ITO) powders were prepared by a coprecipitation method, and the sintering characteristics in fast firing were examined. The mass of the specimen, sintering atmosphere and sintering temperature varied. Oxygen atmosphere promoted the densification in normal rate sintering, while oxygen inhibited the densification in fast firing. Fast firing severely retarded densification as the mass of the specimen

  16. The characteristics study on sintering of municipal solid waste incinerator ashes

    Microsoft Academic Search

    Kuen-Sheng Wang; Kung-Yuh Chiang; Jing-Kae Perng; Chang-Jung Sun

    1998-01-01

    The study examines the sintering of incinerator ashes from municipal solid waste while considering the compact pressure, sintering temperature, and sintering time. Experimental results indicate that the compressive strength primarily influences the compact pressure used in forming the specimens. The specimens' strengths increase at a sintering temperature ranging from 1120°C to 1140°C. However, the strength decreases with an increasing ignition

  17. Decomposition of Niobium Ore by Sodium Hydroxide Fusion Method

    NASA Astrophysics Data System (ADS)

    Yang, Xiu-Li; Wang, Xiao-Hui; Wei, Chang; Zheng, Shi-Li; Sun, Qing

    2013-02-01

    The decomposition kinetics of niobium ore in the NaOH system was studied experimentally. The results show that the reaction products are sodium metaniobate and sodium niobate formed by the reaction of pyrochlore with sodium hydroxide under roasting. The effects of temperature, particle size, and mass ratio of alkali-to-ore were studied. The conversion rate of niobium exceeded 99 pct after 20 minutes at 923 K (650 °C) with a mass ratio of alkali-to-ore 1.2:1 and with initial particle size 75 to 106 ?m. The kinetic study indicates that the shrinking core model is applicable and the process is controlled by a chemical reaction. The activation energy was calculated to be 78.82 kJ mol-1.

  18. Note: O-ring stack system for electron gun alignment

    NASA Astrophysics Data System (ADS)

    Park, In-Yong; Cho, Boklae; Han, Cheolsu; Shin, Seungmin; Lee, Dongjun; Ahn, Sang Jung

    2015-01-01

    We present a reliable method for aligning an electron gun which consists of an electron source and lenses by controlling a stack of rubber O-rings in a vacuum condition. The beam direction angle is precisely tilted along two axes by adjusting the height difference of a stack of O-rings. In addition, the source position is shifted in each of three orthogonal directions. We show that the tilting angle and linear shift along the x and y axes as obtained from ten stacked O-rings are ±2.55° and ±2 mm, respectively. This study can easily be adapted to charged particle gun alignment and adjustments of the flange position in a vacuum, ensuring that its results can be useful with regard to electrical insulation between flanges with slight modifications.

  19. TOP VIEW OF UPPER TRAM TERMINAL, PRIMARY ORE BIN, AND ...

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

    TOP VIEW OF UPPER TRAM TERMINAL, PRIMARY ORE BIN, AND ORE CHUTE,LOOKING SOUTHWEST. TRAM MACHINERY AND GEARS ARE AT LOWER CENTER. A SMALL ELECTRIC MOTOR AT THE REAR LEFT OF THE TERMINAL PROBABLY WAS ADDED AFTER THE ORIGINAL CONSTRUCTION. THE MOVING CABLE OF THE TRAM WAS DRIVEN BY THESE GEARS AND THE LARGE WHEEL UNDERNEATH (SEE CA-291-31 FOR DETAIL). EMPTY TRAM BUCKETS CAME IN FROM THE LEFT, SWINGING AROUND TO THE CHUTES FROM THE ORE BIN TO BE LOADED FOR THE TRIP DOWN TO THE MILL (SEE CA-291-35 FOR DETAIL). THE BREAK OVER TOWER CAN BE SEEN IN THE DISTANCE AT TOP LEFT. THE SUPPORT TOWER BETWEEN THE UPPER TERMINAL AND THE BREAK OVER TOWER IS COLLAPSED. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  20. Chemical constituents in particulate emissions from an integrated iron and steel facility.

    PubMed

    Tsai, Jiun-Horng; Lin, Kuo-Hsiung; Chen, Chih-Yu; Ding, Jian-Yuan; Choa, Ching-Guan; Chiang, Hung-Lung

    2007-08-17

    Particle emissions from four integrated iron and steel plant processes, i.e., coke making, sintering, cold forming, and hot forming, were investigated in this study. Particle compositions of 21 element species, 11 ionic species, elemental carbon (EC), organic carbon (OC) and 16 polyaromatic hydrocarbons (PAHs) were analyzed to create "fingerprints" of the particles emitted from various processes in an integrated iron and steel plant. Results indicated that element compositions (0.11-0.42 g/g), water-soluble ions (0.34-0.52 g/g), elemental carbon (0.008-0.14 g/g), organic carbon (0.02-0.06 g/g) and PAHs (0.52-6.2 mg/g) contributed to the particle mass. In general, sulfur had a higher mass contribution than the other elements, which resulted from the use of coal, flux, heavy oil, and many recycled materials in the iron and steel plant. The particle mass contribution of potassium and chlorine in the sinter plant was higher than in other processes; this may be attributed to the lower boiling point and volatility of potassium. In addition, many recycled materials were fed into the sinter plant, causing a high concentration of potassium and chlorine in the particle phase. Eight PAH compounds were analyzed in the four processes. The carcinogenic compound Benzo(a)pyrene (BaP) was detectable only in the sintering process. PMID:17276592