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By Victor Azbe

Introduction Lime enters our daily life in many ways. Our building, chemical, agricultural, sanitary, and industrial endeavours depend on it to such a great extent that it could probably be called the most important inorganic chemical, and the extent to which it is used might be considered an index of industrial development. Industrial limes vary greatly in quality, due to internal structure and other characteristics. They may be good or bad, sensitive or slow to react. While improper manufacture may not greatly alter the appearance of the lime, it may affect its properties considerably and thus its suitability in the many processes in which lime is used. In some of the processes, one kind of lime is wanted, in others another. While the nature of the stone from which it is made has much to do with whether a lime is suitable or not, its burning and hydration are the crux of the matter. Up to not so many years ago, the knowledge of lime burning was rather imperfect and it is only relatively recently that its manufacture is approaching the state of a higher industrial art. This slow development was in part due to lime manufacture being scattered among many small concerns who, independently, either lacked the inclination or could not afford to strive for a higher technical development.

Jan 1, 1946

By Alan E. Gallie

One of the requirements for the successful waging of war is an unlimited supply of iron ore. In the spring of 1941 the demand for iron ore was expected to exceed the supply. This was particularly so in the case of high-grade lump iron ore, essential to the open-hearth process of making steel. The bulk of Canada's iron ore was imported from the United States. At this time, Canada was making every effort to conserve United States funds for more vital purchases. For these reasons, the development of Canadian iron ore resources became of prime importance. Several companies undertook investigations and one of these examined the old Josephine deposit. Location The Josephine property is in the district of Algoma, in the Michipicoten area of the Sault Ste. Marie mining division of Ontario. It is 120 miles north of Sault Ste. Marie and 20 rail-miles east of Michipicoten harbour, on lake Superior (see Figure 1). Transportation in the area is furnished by the Algoma Central and Hudson Bay railway. The Michipicoten branch of this line passes within a mile of the Josephine mine. Michipicoten harbour provides a port through which iron ore is currently shipped. Power in the area is supplied by the Great Lakes Power Company, with generating plants on Michipicoten river, on Montreal river, and on St. Mary's river at Sault Ste. Marie. A series of transmission lines cover the district and one of these is connected to the Josephine mine by a 3 ½-mile branch line. History The Josephine property was staked by Alois Goetz in 1899. Before the claims could be recorded, the township in which they are located was given to the Algoma Central & Hudson Bay railway as part of a land grant. As a result, the ownership remained in dispute until August 24th, 1906, when a settlement was arbitrated by the Honourable Frank Cochrane. His ruling is interesting and is quoted in part.

Jan 1, 1947

By Wignall. T. K., J. De Geoffroy

Statistical models are fitted to the observed distributions of eighteen characteristics of the population of commercial porphyry deposits of North and South America. The statistical base required for the formulation of the statistical models includes 58 commercial porphyry-copper-molybdenum deposits of the Cordilleran Belt from which geological, geometric and economic data were collected. Predictive and composite models are derived from the statistical study to assist explorat10n. planning, engineering studies and fmanc1al analyses as required for the development of new porphyry deposits in the Cordilleran Belt.

Jan 1, 1973

By Ivan Malinsky, Gérard Castonguay

"On a développé un procédé qui donne une fonte (2,3% C, 0,07% V) du V2O5 (99%) et un rutile synthétique (94% TiO2) à partir d'un minerai, dont les réserves au Québec sont importantes. Le procédé comprend les opérations suivantes: 1) la concentration magnétique du minerai (30% Fe, 9% TiO2 et 0,65% V2O5) pour produire un concentré (65% Fe, 7% TiO2 et 1,6% V2O5); 2) le smeltage du concentré aggloméré dans un four à arc, sans fondant, pour produire une fonte et une scorie (30% FeO, 40% TiO2 et 8,0% V2O5) qui contient plus de 95% du vanadium et du titane présents dans le concentré; 3) le grillage alcalin (37% Na2CO3) de la scorie suivi d'une lixiviation à l'eau et de la précipitation de l'hexavanadate d'ammonium à partir du filtrat; 4) la lixiviation du résidu par l'acide sulfurique pur ou usagé pour produire un rutile synthétique. Un estimé préliminaire de la valeur économique du projet laisse croire à sa rentabilité à la condition que l'investissement pour le smeltage soit inférieur à environ 400$/tonne de fer.IntroductionLes gisements de magnétites titanifères sont nombreux dans le monde. Ils consistent en une magnétite étroitement liée a l'ilménite, La teneur trop élevée en TiO2 empêche l'exploitation de ces gisements pour la production de fer. Cependant, dans certains cas, la magnétite a une teneur intéressante en vanadium qui peut rendre l'exploitation de ces gisements rentable. Aujourd'hui, les magnétites titanifères constituent la plus importante source de production de vanadium. On estime qu'environ 70% du vanadium produit provient de ces sources."

Jan 1, 1983

By Willem P. C. Duyvesteyn

"Scandium International Mining Corp (SCY) has been involved in the commercial development of its Nyngan Scandium Project for about ten years. Various studies at a variety of global R&D organizations have been carried out in an attempt to define the deportment of scandium in both the limonite as well as the saprolite phases of Nyngan ore to assist with process development. Technologies such as sulfuric acid baking, high pressure acid leaching, sulfuric and hydrochloric acid atmospheric leaching and heap leaching have been extensively investigated both at the bench and pilot scale level to arrive at the most economic process flow sheet that will be discussed in some detail in this paper. Solvent extraction, ion exchange and other refining technologies have been tested and an optimum configuration has been established for the Nyngan project which is expected to be the first primary scandium mine and metallurgical plant in the world.Because of a lack of product availability the current scandium market is limited to less than 20 tons per year. Technologies have been identified to produce product with different specifications for aluminum alloys and solid oxide fuel cell applications. Preliminary economics have identified that Nyngan will be a robust and low capital cost project that can readily be expanded as the size of the scandium market increases."

Jan 1, 2016

By J. Esson, R. A. D. Pattrick, M. K. Nimfopoulos, D. A. Polya, K. M. Michailidis

"Economic Mn-oxide ore deposits of commercial grade occur in the Rhodope massif near Kato Nevrokopi in the Drama region, Northern Greece. The Mn-oxide mineralization has developed by weathering of continental hypogene rhodochrosite-sulphide veins. The vein mineralization is con-?ned by tectonic shear zones between marble and metapelites, extending laterally into the marble astabular, pod or lenticular oreshoots (up to 50 m x 20 m x 5-10 m). Supergene oxidation of the hypogene mineralization led to the formation of in-situ residual Mn-oxide ore deposits, and secondary infills of Mn-oxide ore in embryonic and well developed karst cavities.Whole rock geochemical pro?les across mineralized zones con?rm the role of thrusts and faults as solution passageways and stress the importance of these structures in the development of hydrothermal and supergene mineralization at Kato Nevrokopi. Three zones are recognized in the in-situ supergene veins: (A) a stable zone of oxidation, where immobile elements form (or substitute in) stable oxide mineral phases, and mobile elements are leached; (B) a transitional (active) zone in which element behavior is strongly in?uenced by seasonal ?uctuations of the groundwater table and variations in pH-Eh conditions; and (C) a zone of permanent ?ooding, where variations in pH-Eh conditions are minimal. Zone (B) is considered as the source zone for the karst cavity mineralization. During weathering, meteoric waters, which were CO2-rich (PCO2~10-3.8 to 10-1.4) and oxygenated (fO2~10-17 for malachite), percolated downward within the veins, causing breakdown and dissolution of sul?des and marble, and oxidation of rhodochrosite to Mn-oxides. Karst cavity formation was favored by the high permeability along thrust zones. Dissolved Mn2+was transportedinto karst cavities in reduced meteoric waters at the beginning of weathering (pH~4-5), and as Mn(HCO3)2in slightly alkaline groundwaters during advanced weathering (pH~6-8). Mn4+-oxide precipitation took place by fO2increase in ground waters, or pH increase by continuous hydrolysis and carbonate dissolution. In the well developed karst setting, some mobility of elements occurred during and after karst ore formation in the order Na>K>Mg>Sr>Mn>As>Zn>Ba>Al>Fe>Cu>Cd>Pb."

Jan 1, 1997

By Paul L. Broughton

"IntroductionThe coal deposits, all of lignite rank, of economic interest in Saskatchewan are associated with the Ravenscrag Formation (Paleocene). Several Cretaceous formations have less significant lignite accumulations (Broughton, Irvine and W'hitaker, 1974). The Swan River Group (lower Cretaceous) and Judith River Formation (upper Cretaceous) have the only coalbearing strata in the shallow subsurface of central Saskatchewan. The Swan River Group coalfield is relatively small and underlies only 15 sq km of the surface approximately 40 km south of La Ronge, Saskatchewan. An estimated 36 billion short tons are within 45 m of the surface. No reserve estimates are known to have been calculated for the coal-bearing Judith River Formation exposed at the surface in the vicinity of the South Saskatchewan River valley in west-central Saskatchewan. Although no coalfields have been delineated, lignite beds up to 1.8 m thick have been intersected in test holes. The coal-bearing upper Cretaceous and lower Tertiary strata of the northern Williston Basin extends the full width of southern Saskatchewan for 650 km, and from the United States border 120 km north to 50° latitude (Fig. 1). Only the coalfields of the Ravenscrag Formation, because of their economic interest, will be considered further. There are four major coalfields. They are, from east to west: Estevan, Willow Bunch, Wood Mountain and Shaunavon (Cypress) coalfields. Cumulative lignite seam thickness for each basin is 10 -15 m (Figs. 2 and 3). The origin of each coal basin, resource calculations, seam stratigraphy, and mining activity are discussed. Regional Setting The Williston Basin is an ellipsoidal depression in the Precambrian basement, centered in western North Dakota and marginal to the exposed craton of northern Saskatchewan and central Manitoba (Fig. 1). The sediments of the basin range from Cambrian to Pleistocene in age and have a maximum known thickness of 4614 min western North Dakota. A maximum of 3200 m is recorded in southern Saskatchewan. Most structural deformation is late Cretaceous to early Tertiary (Paleocene) in age, coinciding with the Laramide Orogeny. The pre-Laramide Williston Basin, with a depocenter near Williston, North Dakota, began developing during the middle Ordovician, or possibly earlier."

Jan 1, 1985

By J. Esson, R. A. D. Pattrick, M. K. Nimfopoulos, D. A. Polya, K. M. Michailidis

"Abstract-Economic Mn-oxide ore deposits of commercial grade occur in the Rhodope massif near Kato Nevrokopi in the Drama region, Northern Greece. The Mn-oxide mineralization has developed by weathering of continental hypogene rhodochrosite-sulphide veins. The vein mineralization is confined by tectonic shear zones between marble and metapelites, extending laterally into the marble as tabular, pod or lenticular oreshoots (up to 50 m ?? 20 m ?? 5-10 m). Supergene oxidation of the hypogene mineralization led to the formation of in-situ residual Mn-oxide ore deposits, and secondary infills of Mn-oxide ore in embryonic and well developed karst cavities.Whole rock geochemical profiles across mineralized zones confirm the role of thrusts and faults as solution passageways and stress the importance of these structures in the development of hydrothermal and supergene mineralization at Kato Nevrokopi. Three zones are recognized in the insitu supergene veins: (A) a stable zone of oxidation, where immobile elements form (or substitute in) stable oxide mineral phases, and mobile elements are leached; (B) a transitional (active) zone in which element behavior is strongly influenced by seasonal fluctuations of the groundwater table and variations in pH-Eh conditions; and (C) a zone of permanent flooding, where variations in pH-Eh conditions are minimal. Zone (B) is considered as the source zone for the karst cavity mineralization. During weathering, meteoric waters, which were CO2-rich (PCO2 ~10-3.8 to 10-1.4) and oxygenated (fO2 ~10-17 for malachite), percolated downward within the veins, causing breakdown and dissolution of sulfides and marble, and oxidation of rhodochrosite to Mn-oxides. Karst cavity formation was favored by the high permeability along thrust zones. Dissolved Mn2+ was transported into karst cavities in reduced meteoric waters at the beginning of weathering (pH~4-5), and as Mn(HCO3)2 in slightly alkaline groundwaters during advanced weathering (pH~6-8). Mn4+-oxide precipitation took place by fO2 increase in ground waters, or pH increase by continuous hydrolysis and carbonate dissolution. In the well developed karst setting, some mobility of elements occurred during and after karst ore formation in the order Na>K>Mg>Sr>Mn>As>Zn>Ba>Al>Fe>Cu>Cd>Pb."

Jan 1, 1997

By R. J. Hundermark, K. van der Merwe, L. R. Nelson

Taphole integrity is critical to all furnaces, but it is especially important in high intensity electric furnaces processing matte and metal of high superheat. Key furnace dimensions are the electrode proximity to the taphole, hearth sump below the taphole and the shape and location of the taphole in the furnace wall (e.g., circular versus rectangular furnace). In addition, electric furnace power density needs to be matched appropriately to any configuration to achieve operational reliability and furnace integrity. The role of furnace dimensioning is generically reviewed across many pyrometallurgical processes to explore potential impact on furnace taphole performance. Some empirical furnace dimensions and power density ratios of industrial furnaces are then compared to explore to what extent they may indeed influence taphole integrity.

Jan 1, 2015

By C. D. Rowe, H. S. Mitri, J. Malki, I. Vennes

Ore extraction at great depths creates high stresses around mine openings, which can result in violent rock failure in one of various forms of strainburst. This is especially true with strong and brittle rocks, which can store a large amount of strain energy that is suddenly released at failure. The strength and brittleness of rocks have been extensively investigated in the past. The most widely accepted method for the determination of rock burstability is the strain energy storage index obtained from a non-destructive uniaxial load–unload test. However, the results of this method are not always conclusive, showing less repeatability when the target test load is changed. This study concerns itself with the introduction of microscopic analysis as a tool to help validate the strain energy index results when burstability cannot be warranted based on mechanical property tests alone. In this study, two types of rocks, namely, basaltic komatiite (BK) and felsic norite (FNOR) obtained from Canadian underground mines are examined. The selection is based on the premise that felsic norite is known to be burstable from the mine experience, whereas basaltic komatiite is not necessarily burstable. A total of 60 mechanical properties tests were conducted including uniaxial compressive strength, Brazilian tensile strength, and load-unload tests. Laboratory tests on FNOR consistently exhibit high burstability; however, the results for the BK tests are not conclusive. To seek explanations for the mechanical rock behavior, 18 thin sections were examined with optical microscopy and image analysis. The findings show the tested BK specimens are dominated by alteration products, and all primary igneous minerals are lost. There is minor quartz, garnet, carbonate minerals, talc, and serpentine, which give the rock its ductile properties. The FNOR specimens are found to be relatively fresh and supported by a strong network of plagioclase with minor pyroxene, biotite, and secondary micas, explaining the higher stiffness. This study demonstrates how optical microscopy can complement mechanical property tests to evaluate burstability of rocks.

May 4, 2025

By L. Vinnett, I. Panire, J. Yianatos, F. Ruiz

"The effect of operating variables on the flotation performance at steady-state has been extensively used for modelling and simulation of separation processes. However, the dynamic characterization of key variables such as gas dispersion (Sauter mean diameter of bubbles, D32, and bubble surface area flux, SB) and froth discharge rate is rather scarce. In this paper, an experimental design allowed identifying the dynamic response of the flotation process in a laboratory scale flotation cell, using a two-phase system, airwater. The installation included automatic control for the superficial gas rate, JG, and the pulp level. Gas dispersion was evaluated in terms of the Sauter mean diameter of a bubble population and the bubble surface area flux, SB = 6·JG/D32. The D32 was measured using the McGill Bubble Size Analyzer (MBSA) along with a semiautomated algorithm. In addition, the froth discharge velocity was measured in real-time using a Visiofroth system. The control variables were the superficial gas rate and the frother concentration (Teefroth). The dynamic characterization of the flotation process is useful to design algorithms that allow the direct or indirect control of metallurgical variables such as flotation rate, concentrate grade and mineral recovery.INTRODUCTIONGas dispersion indicates the way the gas entering a flotation machine is dispersed throughout the volume of the equipment (Schwarz & Alexander, 2006). The gas dispersion is typically characterized in terms of the bubble size (dB), gas holdup (eG), superficial gas rate (JG), and bubble surface area flux (SB =6·JG/dB) (Finch et al., 2000). All these variables have significant impact on the metallurgical performance of flotation machines. For example, Perez-Garibay et al. (2014) investigated the effect of the particle size, bubble size distribution, superficial gas rate and collector dosage on the flotation performance, for the separation of a sphalerite mineral. The authors observed that recovery increased with the superficial gas rate ranging from JG = 0.04 to JG = 0.08 cm/s and also a maximum recovery was obtained for bubble size close to 300 µm. Gorain et al. (1998) reported a strong correlation between the flotation rate constant and the bubble surface area flux in a zinc cleaner circuit. Both variables were directly proportional at three froth depths in the range of hF =7 - 45 cm. Dobby & Finch (1986) incorporated the effect of the superficial gas rate and the bubble size on the flotation efficiency by means of a kinetic model for the rate constants. Yianatos & Contreras (2010) developed a model to estimate the carrying capacity in large flotation cells by including the bubble surface area flux."

Jan 1, 2016

By E. Dernedde

Cell rooms of aluminium smelters have large openings in the sidewalls and in the roof. These openings provide a high ventilation rate, which removes heat and contaminants emitted by the reduction cells and thereby ensures acceptable working conditions inside the cell room. However the large openings make the airflows through the smelter building sensitive to the wind. In this study equations for the airflow through the openings of a smelter building exposed to crosswinds were developed and verified against plant measurements. The equations were then used to estimate the airflows through a two-storeyed smelter building containing VS Soderberg cells. Wind protection by wind-covers over the sidewall openings and by upwind buildings made the airflows through the building less sensitive to the wind. Physical and mathematical modelling showed that working conditions inside the wind-protected cell room would be acceptable for crosswinds at speeds up to 16 km/h. These predictions were confirmed by measurements taken in a VS Soderberg smelter.

Jan 1, 2007

By P. F. Berry

X-ray fluorescence analytical techniques are fairly well established in the mining and metallurgical industries. In recent years, instruments utilizing radioactive isotopes have been developed which, owing to their more compact size, greater reliability and independence of substantial power supplies, are often preferred to X-ray tube installations. Analyses can now readily be carried out in the field, on the factory floor and in otherwise difficult locations. This paper describes many examples of radioisotope X-ray fluorescence for the analysis of metallic minerals, finished metals and alloys and also for the continuous measurement of metallic coatings, such as tin and zinc, on steel. Radiation scatter techniques are also described for certain analyses and for thickness and density measurements.

Jan 1, 1967

By J. E. Williamson

Introduction 1. Factors on Which the Design of the Roaster Plant was Based The roasting operation at Lake Shore, it was realized from the outset, would be profitable only if costs and losses could be reduced to a low figure. It was absolutely imperative that the operation should be self roasting over the whole range of tonnages and sulphur grades which might obtain during the life of the mine. The roasting operation could not bear the cost in fuel and labour of even a partially fired roast. To meet this requirement, it was necessary to resort to additional insulation in the construction of the roaster and to provide a more flexible means of rabble cooling than the conventional water jacket (see p. 31). A second basic consideration was that of handling a wet, putty-like concentrate. The operating costs of a drier ruled out the possibility of drying the charge before feeding it to the roaster. Moreover, the dusting which would result from charging a dry product virtually all -40 micron (325 mesh) in size would seriously handicap the use of a dryer. Dust lubrication (p. 3S) due to the back-mixing action of the Edwards rabbles, and the use of a Sullivan slapper ( p. 27) on the concentrate filter, completely solved the problem of handling the roast feed. The third consideration was the reduction of dusting to a sufficiently low point that a Cottrell or other dust collecting system was unnecessary. The Edwards roaster when properly supervised, it is believed, can be operated to give the minimum possible dusting. At Lake Shore, the evidence has been that less than 1 per cent dusting occurs at any time and that the greater part of the dust produced is recovered either in the spray tower or in the dust chambers.

Jan 1, 1947

By M. Sahoo, P. Burke, Y. Fasoyinu, J. P. Thomson

The effects of grain refinement, mold temperature and chemical composition on the hot tearing resistance of aluminum alloys 535.0 and 206.0 has been studied by pouring constrained rod castings in metal molds. In addition, two prototype components that could be used in automotive applications were also poured from both alloys by gravity tilt-pour and low pressure permanent mold casting processes. This paper summarizes the results and issues encountered during the casting trials. It was shown that grain refinement and mold temperature ::::: 400°C reduced, and sometimes eliminated hot tear cracks in both alloys. The two prototype engineering components could be cast successfully from both alloys in metal molds. The metallurgical issues related to molten metal treatment and processing temperatures were well controlled. However, issues related to the control of hot tearing, casting and mold design must be addressed in future studies to guarantee the production of defect free castings.

Jan 1, 2006

By Richard W. Hutchinson, Christopher Osterman

Abstract -The Selebi-Phikwe deposits are hosted by amphibolite to granulite facies gneisses of the Limpopo belt. The sulfide orebodies are generally stratiform and conformable to the foliation of the wallrock gneiss. Sulfide remobilization has occurred during metamorphism and has produced discordant sulfide veins, called piercement structures, which project into the hanging wall and foot­ wall gneisses. These piercement structures are compositionally similar to the stratiform sulfides, consisting mainly of pyrrhotite, pentlandite and chalcopyrite. However, texturally the piercement sulfides are coarse grained and inclusion-free, whereas the stratiform sulfides are fine grained and packed with tectonically produced wallrock inclusions. The piercement structure sulfides and adjacent stratabound sulfides were sampled and analyzed for major base metals and PGE's for comparative purposes. Most of the piercement structures were enriched in Cu, Ag and Au, whereas they were generally depleted in Ni, Co, Fe and PGE's. Changing elemental associations were observed from the stratabound sulfides and along the length of the piercement structures. This and the degree of depletion or enrichment of various major and minor elements in the sulfide piercement structures may reflect the relative mobilities of metals under metamorphic conditions. The similarities between sulfide piercement structures and the footwall Cu-POE veins in some Sudbury deposits are reviewed.

Jan 1, 1994

By M. F. Ameur, M. Habak, H. Aouici, M. Kenane

Present study interest by aluminium alloy (Al 7175-T5173) drilled without cooling fluid. The influence of the machining parameters (spindle speed and feed rate) on the holes quality was analyzed. Drilling tools are made of carbide (WC); high speed steel (HSS) and TiN coated carbide (WC-Ti).The Experiment design was reinforced by the application of statistical analysis of variance (ANOVA).The results show that the thrust force is influenced principally by the spindle speed and feed rate. Though, both feed rate and tool materials have statistical significance on the surface roughness. In addition, the objective of correlations between spindle speed and feed rate with the evolution of the machining parameters was established. These correlations were obtained by quadratic regression using the response surface methodology. Finally, useful to select optimum values of drilling parameters, that would minimize thrust force, torque, cutting temperature and surface roughness.

Jan 1, 2015

By Robert A. Creaser, David R. Lentz

Abstract - The Moss molybdenite deposit, which was mined during both world wars, is hosted in late Grenvillian granitic pegmatite dikes. These dikes are locally aplitic, and intrude the late tectonic Onslow syenite (probably correlative with the ~1090-1070 Ma Kensington suite), which is in turn intrusive into the 1170-1155 Ma Chevreuil intrusive suite of southwestern Quebec. A Re-Os model age of 1053 ± 4 Ma (8.3 ppm Re) was obtained for molybdenite from a pegmatitic veinlet within an aplitic phase of the dike. A much younger Re-Os date of 860.9 ± 9.2 Ma (6.9 ppm Re) obtained previously from a pyrrhotiteand pyrite-rich metasomatic vein might reflect Os diffusion during slow cooling of the Grenville province, because this age is consistent with K-Ar dates reported from the region. Alternatively, the similarity between these younger dates may be fortuitous, and may instead relate to sampling issues for molybdenite. The Mo-rich granitic dikes at the Moss deposit are similar to other Mo-rich A-type pegmatite-aplite granitic dike systems that formed immediately after the peak of the Ottawan orogeny (1070-1090 Ma), and possibly are more closely related to the Kensington suite than previously thought.

Jan 1, 2005

By V. Thangadurai

The critical problems in commercialization of the present solid oxide fuel cells (SOFCs) and useful electrical and physical properties of IT-SOFCs electrolytes are discussed briefly. The conductivity behavior of the perovskite-type and perovskite-related structure metal oxides are summarized. Perovskite-type La0.9Sr0.10ao.8Mgo.203_8 (LSGM) exhibits high ionic conductivity of 0.1 S/cm at 800 °C. In order to improve the electrical conductivity of LSGM and the In analogue of LSGM, substitutions have been made at the A-and B-sites. Substitution of trivalent La3+ by isovalent Pr3+ in LSGM and La09Sro ilno.sMgo.202.85 (LSIM), yield new mixed conductors. Among the investigated compounds in the present study, La0APro.4Sro.21no sMgo.2028 exhibits the highest total electrical conductivity of 3.2 x 10-5 S/cm at 200 °C in air with the lowest activation energy of 0.44 eV (200-700 °C). LSIM and Pr-substituted LSGM and LSIM perovskites show p-type electronic conductivity in the oxygen partial pressure range 10-5 ? 0.21 atm at 750 °C. The perovskite-type solid solution SrSn1-xFex03 exhibits compositionally driven phase transitions. For example, compound of the composition x = 0 to 0.3 crystallizes in an orthorhombic GdFeO3-like perovskite structure, where as that of x = 0.4-0.9 crystallizes in simple cubic SrTiO3-like, and that of x = 1 in orthorhombic structure. The electrical conductivity of SrSn1_xFex03 increases with the increasing Fe content and reaches a value of about 10-1 S/cm at 25 °C in air for x = 1. Compounds with low Fe content exhibit both ionic and electronic conductivity, while the higher Fe content 0.5) perovskites are electronic conductors over a wide range of oxygen partial pressure of 10-22? 0.21 atm at 750 °C.

Jan 1, 2005

ABSTRACT Understanding process histories and worker exposures in nickel production operations is critical in determining the role nickel compounds play in respiratory cancer incidence. As part of a series on Vale Canada’s (previously known as Inco) nickel processing operations, this paper includes descriptions of Ni electrolytic operations at refineries in Port Colborne, Ontario (1922–1984), and Thompson, Manitoba (1961–present). Industrial hygiene measurements, by area and personal sampling, of workplace aerosols at these operations are reported.

Jan 1, 2014