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By Robert M. Busche

[Recent developments in the gasification of coal, both by the Bureau of Mines and American industry, have intensified interest in the thermodynamic and kinetic principles necessary for understanding the reaction mechanism and rates and the physical changes that take place. In the course of a Bureau of Mines study of the kinetics of coal gasification at the Synthetic Liquid Fuels Demonstration Plant, Louisiana, Mo., a bibliography of approximately two references was compiled. They are listed n this publication and refer both to American and foreign sources.]

Jan 1, 1952

By A J. H Newell

The background and the basis for conducting a Technical Due Diligence are discussed as well as the source information, typical studies and potential limitations. Typical short comings including ‘show-stoppers’ are presented for the metallurgical area, with examples. Issues found in other areas such as geology, mining, infrastructure and financial evaluations are briefly reviewed, highlighting the input and interaction required by metallurgists with these disciplines. A checklist is provided as a guide to maximise the success of a Due Diligence as well as a check on the quality of a Feasibility Study.CITATION:Newell, A J H, 2015. Fatal flaws in technical due diligences, in Proceedings MetPlant 2015, pp 61–77 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 7, 2015

By J. Astier

The idea of using only one strand for both sintering and cooling of the sinter is not new. In 1952, in the U.S.A. a sintering plant was built at Benson Mine (Star Lake, N.Y.), including : - 68 m2 or 735 sqft (8 wind boxes) for sintering, - 22 m2 or 237 sqft (3 wind boxes) for cooling. In the USSR, a large number of machines have been built allowing for cooling of the sinter on the strand, especially the 4 m (about 13 ft) machines, with : 252 m2 sintering grate area 60 m2 cooling grate area 312 m2 total grate area. However, such ventures did not prove very successful, and the IRSID embarked many years ago on a research program to discover : - what are the problems associated with cooling on a sintering strand ; - what are the possible solutions for industrial plants.

Jan 1, 1974

By J. C. Agarwal

A significant portion of the, coal mined by U. S. Steel is beneficiated to upgrade the quality of the resultant coke to meet blast-furnace requirements. Primarily because of degradation from modern mechanized mining methods, a considerable quantity of the coal to be beneficiated is in the 1/4-inch by 100-mesh size range. In the cleaning plants, this coal is usually cleaned on concentrating tables and then mechanically dewatered in solid-bowl centrifuges to 9 to 14 percent water. At some plants, to further decrease the amount of water shipped with coal, and to improve the coking characteristics of the coal at its destination, mechanical dewatering is followed by thermal drying. At U. S. Steel's-Alpheus preparation plant at Gary, West Virginia, approximately 50 percent of the total coal produced is in this fine size range, and two fluidized-bed dryers are used for the thermal drying step. The two fluidized-bed dryers are 14 feet in diameter and were designed by the Dorr-Oliver Company. Although the original design called for a rate of drying equivalent to 37 tons, of moisture per hour, presently they are removing twice that amount. This paper describes, the major problems encountered' in operating these dryers at the present, high capacities and how they were overcome.

Jan 1, 1963

By Sinha D. K.

As the main source of indigineous energy, coal has a big role to play in the development of national economy of India. Nationalization of the coal mining has brought the entire industry under the unit control of the Central Government following which an ambitious plan for increasing the coal production in the next few five year plans has been undertaken. In order to achieve best all round results, economy-mathematical models of Planning the total system, right from the highest to lowest hierarchial levels of decision making, have been proposed through a Global Model which is detailed in Local Models in stages right up to a mine. Optimum obtained by computer solution of the models would provide basis for objective decision making in the fields of selection of optimum plan for developing the industry, the coal fields and the mines with construction and/or reconstruction of mines, capacity optimization of enterprises and mines therein. Different types of Models and the optimization processes are presented.

Jan 1, 1977

By K. Nassau

The Effect of tin and hydrogen on the C0 parameter of a titanium. specimens were capsule cooled in water to eliminate contamination by water. Deybe-Scherrer photograms were obtained in a 114.6 mm camera with CuKa radiation. The parameters shown in Table I and Fig. 1 were calculated from the 213 (8569°) and 302 (8173.5°) reflections? no attempt being made to correct for systematic errors. The principal difference in method of preparation of specimens between this investigation and that of Worner was the use of pickling by the latter to produce X-ray diffraction samples. The possibility that hydrogen introduced by pickling was responsible for the lower a and c-parameters was investigated with the same 80 pct HNO3- 20 pct HF solutions used by Worner. The 6 and 10 at. pct specimens, the parameters of which had already been determined, were pickled and the c-parameters obtained are also shown in Fig. 1. The a-parameters, not shown, are also diminished. The quality of the lines obtained from the unetched and etched samples was unchanged, being quite sharp in both cases. It is quite possible that if corrections for systematic error carried out that the parameters obtained for the unetched samples would approach the data of Worner. In any event, the parameters of the etched samples would be still lower. The data obtained here is evidence that hydrogen in solution has contracted the c and a -parameters. Crystallographic Angles of Calcium Tung-state (Tetragonal, c/a = 2.169) K. Nassau In connection with the preparation and orientation of single crystals of calcium tungstate (Scheelite -CaWO4), the need arose for a stereographic projection for this tetragonal material. There appear to be no tetragonal projections with a c/a ratio above that of indium1 (c/a = 1.522) in the literature. In addition to its use for calcium tungstate, such a projection might find other more general applications and is accordingly presented below. The most recent X-ray diffraction work on CaWO4 is that of Swanson, Gilfrich, and Cook,2 where a summary of previous work is also found. Lattice parameters given are: a = 5.242A, c = 11.372A, and c/a = 2.169. The material is tetragonal with space group Table I, giving angles between crystallographic planes (HKL) and (hkl), was calculated from the formula3

Jan 1, 1961

By Daniel M. Bass, Paul B. Crawford

Laboratory investigations have been made to study the effect of variations in fluid characteristics, gas saturation, water saturation, and water injection rate on oil recovery by water flooding. Three synthetic gas-saturated crude oils having bubble points of 860, 1,540 and 1,885 psi were used as reservoir fluids. Repeated tests were made in which a and pack, saturated with water and synthetic oil, was produced by solution gas drive followed by water flooding at various pressure levels. Oil recovery by solution gas drive and subsequent water injection is shown to vary with the pressure and rate at which the water flood is conducted. The pressure at which optimum flooding conditions exist is shown to be a functiotl of the physical characteristics of the reservoir fluid. For the systems studied, increases in oil recoveries of near 10 per cent were obtained by flooding at the most desirable conditions. Va- riations in initial water saturations gave results similar to those in the literature. INTRODUCTION Most of the waterflooding studies investigating means of improving present exploitation processes have been conducted at low pressures with little effort to simulate reservoir conditions. Holmgren and Morse' performed a waterflooding study at 300 to 500 psi wherein the gas saturation was created by injecting gas, letting dissolved gas evolve from the oil, and then flushing the core with "live" oil until the desired gas saturation was obtained. Their results show increasing oil recoveries with increasing gas saturations. Data presented by Guerrero' and Kennedy, et al, indicate that in some instances water flooding at approximately 500 psi below the original bubble point results in a lower residual oil saturation than is obtained when water flooding above the bubble point. In their work gas saturations were created by primary depletion. By correcting low pressure flooding data for fluid shrinkage, Dyes found that a maximum oil recovery may be obtained by flooding with initial gas saturations of from 7 to 12 per cent. The purpose of this work was to determine the variations in oil recovery caused by initiating a waterflooding program at various stages of primary depletion of a core. This is a part of a more comprehensive study of obtaining criteria for determining when to initiate a pressure maintenance program and what fluids to in-ject. EQUIPMENT A schematic diagram of the apparatus is shown in Fig. 1. Fluid transfer was accomplished with metering pumps. Pressure control was ob-

Jan 1, 1957

By J. B. Wagner, B. Swaroop

The atomic ratios of oxygen to iron in zlarious corn-posilions of wustite in the vicinity oj the reported p to n transformation were determined in the temperalure range between 950" and 1250°C. For these conditions, equilibrium vacancy concenrations have also been determined at vatious mixtures of C0,-CO. The data show a continuos introduction of iron vacancies as oxygen is introduced into wuistite. No phase change is observed with in the wuustite field. However, the value of n in the isothermal oxygen pressure dependence, the weight change shifts to 1ower values as the concentration of oxygen increases. WUSTITE is a metal deficit semiconductor with the majority lattice disorder being cation vacancies. Using the notation similar to that of Kroger and ink,' the dissolution of oxygen into wiistite using C02-CO mixtures is represented by, WHere v+! denotes a cation vacancy with k effective negative charges and kh • denotes k electron holes, h -. Applying the law of mass action and assuming a dilute solution of defects in the wiistite yields Where the square brackets denote concentrations. Furthermore, when k = 2 the cation vacancies are completely ionized, and both the concentration of cation vacancies and the concentration of electron holes are proportional to the third root of the ratio, PC /PCo. This analysis is valid for one particular mael based on an ideal solution at elevated temperatures (in this case t > 1000°C). At lower temperatures, it has been shown2 that the pressure dependence of the electronic conductivity changes in a manner which suggests that vacancies interact with or "trap" electron holes. At the very high concentrations of defects, 10'' to 10" per cu cm, these simple models no longer hold. Recently Tannhauser,3 Geiger et a1.' Bransky and Tannhauser; and Hillegas' have found an apparent p to n transformation in wiistite in the temperature range of 950" to 1300°C. This junction was found by thermoelectric and electronic conductivity measurements. Geiger eta1.' found that the electronic conductivity became almost independent of the oxygen pressure at high temperatures and oxygen concentrations within the experimental error. In addition, Vallet, Raccah, and coworkers6'7 have reported the existence of several "varieties" of wiistite which were reported to exist within what was heretofor presumed to be a

Jan 1, 1968

By F. M. Yans, A. D. Donaldson, A. R. Kaufmann

Beryllium was mixed by powder. metallurgical techniques with copper, nickel, iron, and chromium, respectively, to form beryllium -rich binary alloys which Mere then extyuded and rolled transtverse to the extrusion direction. The effect of each alloying element was determined by tensile testing. In solid solution, small amounts of iron and nickel had an embrittling effect, while copper in solution increased the strength but had no effect on ductility. The effect of chromium was complicated and not readily explainable. Observations concerning the planes and modes of fracture were made. BERYLLIUM possesses some very attractive properties for general design applications, especially its strength to weight ratio which is approximately twice that of aluminum and three times that of stainless steel. Equally significant, however, is its combination of high moduli , high strength (approximately 70,000 psi tension and 40,000 psi shear), and low density (0.0658 Ib per in.3), which has made it a potentially important structural material for use in high-speed aircraft and missiles. The main attractions of beryllium are most marked when compared to other constructional alloys now in use. For example, while its density is approximateiy that of magnesium, its modulus of elasticity is approximately seven times that of magnesium, three times that of titanium, four times that of aluminum, and 1 1/3 times that of steel. Furthermore, its relatively high strength and high melting temperature permit design for service temperatures to about 1100°F. It is felt by the aircraft industry in general,' that the high cost of beryllium can easily be amortized by the savings in fuel costs, and increases in aircraft payload and range. The only factor which has prevented the use of the metal in structural applications is its lack of sufficient ductility. It is this property that has retarded the development and utilization of beryllium. Beryllium's modes of deformation, Fig. 1 indicate that the main fracture planes at room temperature in a randomly oriented sample are the (0001) basal planes; the (1150) prism planes are the planes of secondary fracture.' Klein, Macres, Woodard, and Greenspan3 obtained elongations of up to 40 pct in beryllium sheet rolled above 700°C when the (0001) basal planes were oriented parallel to the plane of the sheet (see Fig. 2).

Jan 1, 1962

By David J. Lowell

The gold content of porphyry copper deposits ranges from less than 0.05 g/t to more than I g/t ((0.0017 to 0.035 oz per st) and the average is about 0.05 g/t (0.0017 oz per st) gold. Perhaps the highest grade mineralization found near a porphyry cop¬per deposit is the Ok Tedi Gold Cap ore body whose grade falls in the 2 to 3 g/t (0.07 to 0.1 oz per st) range. It is difficult to define a gold-rich por¬phyry copper deposit. All porphyry copper ore bodies contain some gold, but there seems to be a fairly sharp break in the gold content at about 0.1 g/t (0.003 oz per st) gold. There is also a problem in identifying dis¬seminated gold deposits that may have an indirect relationship to porphyry copper systems. This relationship is clear cut in deposits such as the Ok Tedi Gold Cap, the El Hueso deposit, the Fortitude and West de¬posits at Battle Mountain, NV, and the Sur¬prise deposit at Ely, NV. There are many other bulk disseminated, epithermal-type gold deposits - McCoy, NV, for example - that might be related to a porphyry system but where this relationship is remains very uncertain. In such places as the Goldfields and Tonapah district in Ne¬vada and in the El Indio, Chile district, there may be a vertically stacked ore deposit rela¬tionship between near surface epithermal deposits and disseminated molybdenite and chalcopyrite enargite mineralization at depth that may represent a deep porphyry system. This, however, has not been positively demonstrated. Most of the bulk epithermal gold deposits are probably not related to porphyry copper systems. Exceptions would probably be Ok Tedi, El Indio, El Hueso, Battle Mountain, and Lepanto where vertical or lateral zoning relationships are more apparent. This author believes that porphyry copper systems are related to a relatively unique type of intrusion that is probably distinct from, for example, the McCoy intrusivebody. For that reason, deposits such as McCoy, Chimney Creek, and the like will not be included in the definition of gold-rich por¬phyry copper deposits for this article. The interpretation of the origin of several of the deposits previously mentioned are subject to an unusual amount of contro¬versy. For example, geologists seem to be equally divided about the presence of a porphyry copper deposit below the El Indio deposit. Geologic setting Continental vs. island arc Several geologists have speculated that the gold-rich, moly-poor, porphyries are

Jan 1, 1989

By E. T. Turkdogan

This paper deals with an analysis of the conditions leading to the formation of blowholes and surface and subsurface defects in cast low-carbon steels. The theoretical analysis of the problem is based on the concept of the occurrence of deoxidation reactions during cooling of liquid steel and during its solidification. The reaction equilibrium data are given on deoxidation of steel by carbon, silicon, and manganese. The details of the calculations are given on the simultaneous deoxidation of steel by silico-manganese additions to produce a desired level of deoxidation at certain residual concentrations. Based on an idealized model, an attempt is made to calculate the enrichment of solutes in the solidifying liquid entrapped within the interdendritic cells which are known to be less than 200 µ thick. Formulae are derived for the calculation of the change in the residual oxygen content of the enriched liquid steel, controlled by Si/Mn deoxidation. It is shown that for every particular initial silicon, manganese, and oxygen concentration in steel (as residuals in liquid solution at the beginning of solidification) there is a particular carbon concentration below which carbon monoxide, leading to blowholes or pinholes, is not expected to form. There are a number of independent variables which have a decisive influence on the formation of blowholes. For example, it is shown that the position of the curve depicting the critical relation between initial silicon and carbon content for suppression of the evolution of carbon monoxide) can be shifted to lower silicon or higher carbon levels by: increasing manganese content; decreasing oxygen, hydrogen, or nitrogen content; or increasing external pressure on the solidifying mass. FOR the production of sound castings it is essential to prevent the formation of interdendritic worm-holes or pinholes brought about by gas evolution during solidification. Another major problem encountered in solidification of ingots is the formation of surface defects. These problems are thought to be closely associated with the deoxidation reaction occurring in liquid steel during cooling and subsequent solidification. As the liquid becomes richer in impurities during dendritic solidification of steel, a series of reactions may occur in the liquid phase trapped within the branches of growing dendrite platelets. Because of the strong interaction between dissolved oxygen and impurities in liquid steel, the reactions most likely to occur are of the deoxidation type. However, inherent to the extreme complexity of the problem in question, numerous simplifying assump-

Jan 1, 1965

By Edmund J. Cardoza

The paper describes the design, construction and quality control aspects of the installation of a cement-bentonite (CB) cut off wall to impede seepage through a flood control dike. Special emphasis is placed upon the development of a proper specification, distinguishing the CB method from the Soil-Bentonite technique. The importance of the pre-construction laboratory testing program and field quality control procedures is emphasized by the fact that the in-place properties and characteristics of the CB cut off may not be known until after a majority of the work is complete. Sections are included which describe the construction method, the specialty equipment and personnel requirements and the quality control/quality assurance aspects of the project.

Jan 1, 1992

By William M. Knuth

The objectives of this study were the evaluation of the technical and economical feasibility of utilizing color and color infrared aerial photography to satisfy some informational needs for pre-mine planning, mine progress monitoring, and reclamation monitoring. Seven aerial data collection missions were conducted within a two year period over strip mine sites in Pennsylvania. Scales of 1:6,000; 1:12,000; 1:24,000; and 1:48,000 were flown on the first aerial mission. The 1:12,000 was chosen as the optimal scale for the remaining six flights. An extensive literature and legislative review and discussions with strip mine operators identified the informational parameters that could possibly be obtained from aerial photography. Interpretability accuracies were evaluated for parameters in the broad categories of land use, soils, water, vegetation, and geology. Seasonal interpretation characteristics were noted for infrared photography. Man hours for photointerpretation and costs of aerial data collection were monitored closely and incorporated into a cost benefit analysis. Those parameters that could be mapped, identified, or measured with accuracies =75 percent were incorporated into a photointerpretation training manual. An additional analysis was performed to determine the applicability of the interpretation methodologies and results developed for Eastern sites to Western surface coal mining sites. In addition, a separate aerial photographic interpretation manual was produced during this contract. It is intended to be utilized by eastern and midwestern surface mine operators and regulatory personnel.

Jan 1, 1978

By Donivan L. Gordon

One of the several problems facing society today is that of disposing of its solid waste. Each year this nation spends approximately 4.5 billion dollars to collect, transport and dispose of some 360 million tons of domestic and industrial solid waste. Although considerable sums of time and money have been spent in researching various techniques for solid waste disposal, it is presently agreed that sanitary landfilling represents the most economic and universally adaptable solution to the problem of solid waste disposal. However, regardless of the factors favoring sanitary landfilling as the waste disposal method of choice, it should be recognized as carrying with it a potential for the degradation of ground- and surfacewater resources. Through an interdisciplinary effort regulations were promulgated during 1971 in the State of Iowa to govern sanitary disposal projects. Consistent with a set of rationales developed to preserve environmental quality, these regulations set forth hydrologic and geologic standards designed to protect Iowa's water resources. Minimum requirements have been outlined in the regulations through which the natural favorability of potential landfill sites may be evaluated. Natural favorability is primarily defined in terms of the hydrologic and geologic relationships between a proposed landfill site and those in the locality of the site. The regulations specify that leakage from a landfill to a subcropping aquifer must be less than 0.04 cu ft/day/sq ft at the base of the landfill. This factor is offered to quantify the maximum allowable leakage for all sites in unconsolidated sequences underlain by subcropping bedrock aquifers, Based on groundwater research in Iowa, the assumption is made that 50 feet of till will be sufficient to inhibit the downward flow of liquids from a landfill into bedrock aquifers. This assumes a difference of no greater than 40 feet in hydrostatic head between the water table in the unconsolidated sequence and that in the bedrock aquifer. Owing to the fact that bedrock aquifers in many areas of the state are mantled by less than 50 feet of till the regulations provide for site modification, through engineering, to meet the specified leakage standard, In such instances the leakage factor is evaluated by means of the generalized Darcy's Law Q = PIA where:

Jan 1, 1974

By F. D. Stevenson

Thermodynamic properties of metal halides and, in particular, vapor pressures have become of great importance in recent years owing to increased application of chemical processing to extraction of metals from their ores. Vapor pressure data serve not only as a valuable source of latent heat of vaporization and fusion values but also differences in metal-halide vapor pressures often provide the basis for their separation by conventional mass transfer operations. This literature search was made to provide a ready reference to experimental vapor-pressure data of metal halides and oxyhalides. Results are reported in two main sections: (1) A tabulation of vapor- pressure references for each of the metal halides (listed by metal) for which actual experimental data are reported (table 1), and (2) a bibliography of the citations. Metal halides and oxyhalides are listed by chemical formula and chemical name, based on the stock4 system. To facilitate location of the references, a listing of the journal titles and their abbreviations follows the bibliography.

Jan 1, 1963

By C Paoletti

About 15 years ago the debate on the reliability of sampling procedures for agricultural food and feed commodities was initiated by a few brave scientists who questioned the representativeness of what, at the time, were routine sampling procedures established exclusively on the basis of tradition and practical feasibility. Over time several national and international organisations contributed to the discussion, developing standards and publishing papers either to underline the fact that sampling is always a source of error, in itself, which cannot be overlooked, or to minimise the relevance of sampling on the basis of argumentations linked to time and money limitations. The latter dominated, but is nevertheless impossible to accept from both a scientific and a responsible management perspective. Here the author presents an historical overview of these past 15 years, illustrating the most controversial issues, reporting major achievements in food/feed sampling, highlighting milestones, as well as unresolved problems that still need the attention and contribution from the sampling community. The need to incorporate Theory of Sampling (TOS) into food/feed safety assessment (pre-market), as well as into food/feed safety monitoring (post-market) has recently been highlighted, and the practical applicability of TOS to base food/feed safety decisions on representative sampling, has been explored and documented via concrete examples of risk analysis in different areas of food/feed industrial production chains. Now it is time to move forward and ensure that TOS is fully integrated into the well-established Food and Agriculture Organization (FAO) / World Health Organization (WHO) risk assessment approach, in order to guarantee a transparent and correct universal frame for risk assessment and the subsequent management decision-making process. WCSB8 offers the ideal platform to explore the best way to do so, switching from a theoretical discussion of correct sampling principles for food and feed agricultural commodities to practical recommendations in the interest of consumers, worldwide. These 15 years have also been a personal journey of interesting dimensions, indeed a veritable roller-coaster ride in-and-out of the scientific, technological, industrial and (last but not least) regulatory worlds. The start was WCSB2 in 2004, when I flew to Australia to discover if in other areas sampling had been identified as an unavoidable issue and, if so, what the solution was. There, I found a good travel companion who today is still on my side, to assemble the puzzle and explore how to shape the future, to concretely answer to the 15 years’ quest for proper sampling in the assessment and monitoring of food/feed safety.CITATION:Paoletti, C, 2017. Assessing and monitoring food and feed safety – a 15 year quest for proper sampling, in Proceedings Eighth World Conference on Sampling and Blending , pp 39–44 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2017

By Hong Nguen Vu, Pavla Ovcarí, Peter Fecko, Barbara Tora

The aim of this paper is to evaluate the suitability of a coal sample from the mine Jaworzno (Poland)- locality for bacterial leaching. Laboratory research used a pure bacterial culture of Thiobacillus ferrooxidans. The results showed that bacterial leaching was effective, with a one month leaching time, when 65% of total sulphur and 85% of pyritic sulphur was leached. The paper describes changes to the pyrite during and after bacterial leaching.

Jan 1, 2003

By D R. Anstey

The mining of magnetite iron ore in Western Australia will generate large volumes of waste rock and tailings over many decades. The need to dispose of these materials will result in massive waste landforms that will require significant planning and management. The formation of comparable man-made landforms is relatively common, as exemplified through past practice in gold and iron ore (haematite) mining. Unfortunately, the performance of these landforms, with respect to long-term stability (erosion resistance), the release of low pH seepage water and aesthetic impact, has commonly been disappointing and environmental legacies have been created as a result. Lessons that have been learnt from past, large mining operations indicate that there is a need to rethink the methods of waste disposal and landform development applied to magnetite mining. The environmental compliance criteria applied to magnetite mines for the storage of tailings and waste typically include minimising dust generation (particularly as the tailings and mine waste may contain asbestiform minerals), control of silt, minimising visual intrusion and management of potentially acid forming materials. In addition, the climate of Western Australia and the paucity of both surface and groundwater in the vicinity of the magnetite mines frequently necessitate water consumption to be minimised. This paper discusses the potential to co-mingle magnetite mining waste streams in a variety of ways to concomitantly satisfy the environmental compliance criteria and the operational requirements of the mine. These methods include co-mingling of coarse tailings and waste through dry-stacking, deposition of tailings as a paste, co-disposing of all wastes to form an integrated landform and the co-mingling of all waste streams to produce PasteRockTM (a blend of tailings paste and crushed waste rock). The paper demonstrates how these techniques can be applied to the magnetite mining industry to provide better outcomes than might be achieved using more conventional techniques, currently employed in large-scale mining operations.

Jan 1, 2009

By A. McLean, W. Q. Chen, W. Yan, M. Barati, Y. D. Yang

In order to maximally remove the harmful impurities phosphorus and reduce the loss of valuable elements from Si-based alloy for production of solar-grade silicon, thermodynamic properties of the Si-based alloy were studied. In this work a new model, the Molecular Interaction Volume Model (MIVM) derived from statistical thermodynamics, was successfully used in the Si-based and Si-Fe-based alloy. The calculation started from binary Si-Fe, Si-P and Fe-P systems, then the thermodynamic parameters of ternary systems could be derived based sub-binary systems. Using the activity coefficients of the elements in the Si-based alloys and the saturated vapor pressure of the pure substance of the components, mass fraction of P during vapor-liquid equilibrium can be calculated. The calculated thermodynamic parameters were compared with experimental data available in different publications, and it is found that the thermodynamic parameters calculated using MIVM model are in good agreement with the measured results. The calculated result shows that the mass fraction of phosphorus during vapor-liquid equilibrium of Si-Fe-P melt increases with the increasing phosphorus content and decreasing temperature. This is an important direction for experimental practice in vacuum or low-pressure EML refining of ferrosilicon for potential production of solar-grade silicon without significant vaporization loss of valuable element.

Jan 1, 2015

By Fredrick C. Kruger

We can confidently predict such obvious long-term trends affecting the minerals industry as - increasing consumption, exhaustion of easily discovered near-surface ores, and sharp limitations upon open pit mining by environmental considerations. There- fore, we must intensify the exploration for, and the development and exploitation of, deep bodies of potash and other ores. This paper examines the state of the art of the search for, and the evaluation of, potash from both a geological bias and a mining practicability. The use of indirect geological methods and geophysical techniques, followed by expensive deep drilling, are the conventional approach to evaluation and development of mining plans. The geologist and the geophysicist will have to find ways to perform both of these tasks better and cheaper.

Jan 1, 1973