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By D. M. Hausen

It has been demonstrated that microscopic techniques can be applied in a practical manner to the study of spodumene liberation in the processing of pegmatitic ores at the Kings Mountain spodumene plant, Kings Mountain, North Carolina. Spodumene and associated non-opaque gangue minerals are identified and quantified by microscopic point-counting of polished thin sections of heads, concentrates, middlings and tails fractions. Specially prepared polished thin sections? provide uniform thickness of particles for measurement of diagnostic optical properties and the alternate use of incident and transmitted light in distinguishing the various gangue and ore minerals. Spodumene is commonly associated and interlocked with quartz, albite, microcline and muscovite. Concentrate grade depends on the degree of spodumene liberation, which in turn depends on the crystal size and textural association of interlocked minerals. The liberation of spodumene can be measured as a function of screen size by means of microscopic point-count data. Microscopic data also provide useful metallurgical information about the nature of diluent minerals in spodumene concentrates, and the form of lithia losses in the tails. Lithium assays correlate closely with microscopic spodumene analyses in various flotation products from Foote Mineral's Kings Mountain plant, and confirm the applicability of quantitative optical microscopy to the study of liberation and recovery of spodumene from pegmatitic ores. A better understanding of recovery-grade relationships was developed as a result of quantitative microscopy studies.

Jan 1, 1981

By M. Radwan

This research reports on the synthesis of advanced silicon-based structural ceramics from mixtures composed of natural sand (Sinai white sand), reclaimed silicon and graphite by the nitriding combustion synthesis method. With pulverized sand (? 40 m), we found that the nitriding combustion can be realized at self-sustaining mode in the SiO2?Si?C system under 3 MPa nitrogen pressure. Depending on the composition of the starting mixtures, single-phase silicon oxynitride (Si2N2O) powder as well as new Si3N4?Si2N2O and Si2N2O?SiC composite powders with controllable chemical compositions were successfully developed. The measured thermograms of various combusted mixtures and the thermodynamic characteristics of possible exothermic reactions in this system were discussed to explain the nitriding combustion behaviour and mechanism. Near-full dense Si2N2O were fabricated from synthesized Si2N2O powder with 5 wt % oxide additive by the spark plasma sintering (SPS) method at 1600 °C. The dense Si2N2O samples had good mechanical properties (18.7 GPa Vickers hardness, 3.3 MPa m1/2 fracture toughness and 363 MPa strength) and excellent chemical and oxidation resistance. The synthesized composite powders were also densified to high densities (> 90 % of theoretical values) by SPS technique. The results obtained in this study can be seen as a new route to prepare important silicon-based structural ceramic powders with various compositions/properties from cheap starting materials which makes them potential for wide range of applications.

Jan 1, 2006

By Dietrich Gross

This paper describes an advanced oxy-fuel combustion technology for re-melting aluminum that significantly reduces energy consumption and emissions. This oxy-fuel combustion technology developed by Jupiter Oxygen is a patented process for combustion of fossil fuels with pure oxygen while excluding air, thereby creating an undiluted high flame temperature and increased efficiency for process heating in industrial furnaces. This unique process has led to improved heat transfer and longer residence time while maintaining the same process temperatures as with air combustion. The energy efficient combustion process allows aluminum companies to operate at a substantially lower cost due to a dramatic fuel savings of up to 70% for natural gas and waste oil (1). The results of more than 10 years of day-to-day experience utilizing the Jupiter Oxygen Corporation oxy-fuel combustion technology licensed to Jupiter Aluminum Corporation in the aluminum re-melting business are discussed.

Jan 1, 2008

By H. P. Wang, E. M. Perry

"Analytical solutions for investigating the solidification of casting problems with initial superheat and natural boundary conditions have been derived using an integral method. There are two moving interfaces in the solution field, one for the phase change line and the other for the superheat line. Two coupled nonlinear differential equations, representing two moving layers, were calculated by the Runge-Kutta numerical integration scheme. The solutions are in terms of six dimensionless parameters: phase change number, two Biot numbers for interfaces, diffusivity ratio, and dimensionless superheat temperature and time. Parametric studies on these parameters have been conducted to provide generic information about this phase change problem. This analytical information is extremely useful for validating numerical solutions. A simplified I-D finite element model was constructed for the purpose of comparison. The excellent agreement between the analytical and finite element solutions has proven that they are mutually validated.This validated finite element modeling tool was then used for modeling an investment casting process of a super-alloy with a simple geometry: a two-step plate. The nonlinear latent heat release, a common property of alloy materials, was approximated by several piecewise linear segments. The transient temperature response of this 2-D finite element solution, including a metal/mold gap resistance, shows excellent agreement with experimental data.This fundamental work provides a solid basis for further work on the development of a process modeling tool for the complex investment casting process.IntroductionAt present, the investment casting process is used in a variety of industries. In the aircraft engine industry, in particular, investment casting is used to produce parts ranging from turbine blades to engine frames. Because a large single casting can replace many component parts that require machining, fabrication, and assembly, this one-piece casting approach becomes a very cost-effective manufacturing process.The main constraint in using this process for mass production is the long design-to-production lead time. The standard rigging design is still an art, based on the experience of casting experts, rather than on scientific methods. Many trials are often required before making a sound final casting. In order to .reduce the number of expensive casting trials, the development of computer-aided tooling technology is needed.The fundamental physics describing this manufacturing process can be simply described. They reduce to a solid/liquid phase change problem, with two parts - first, the thermal balance of the initial superheat temperature of the molten metal and the preheat temperature of the ceramic shell through heat conduction, and second, the energy release from the mold surface to the ambient by radiation."

Jan 1, 1986

By Sang Han Son

The vapor pressures of FeCI2 and ZnC12 in the FeCl2-ZnCl2 system were measured by the transpiration method at 873K and 917K. The vapor pressure data were interpreted to indicate the formation of complex ions in the FeCl2-ZnCl2 melts. It is presumed that the complex molecule FeZnCl4 as well as FeCI2 and ZnCI2 exists in the vapors in equilibrium with molten FeCl2-ZnCl2 mixtures. The activities in the FeCl2-ZnCI2 system are shown a negative deviation from Raoult's law. These results suggest the formation of complex ions such as ZnCl42- in molten FeCI2-ZnCI2 mixtures.

Jan 1, 2003

Cuspidine (3CaO?2SiO2?CaF2) is one of the most important compounds crystallized in mold flux films during casting in the continuous casting process of steel. The primary crystallization field of cuspidine has been experimentally developed in the CaO-SiOrCaF2-SiF4 system. The cuspidine-NaF binary and cuspidine-CaF2-NaF ternary systems have been also experimentally determined to study effects of addition of NaF on the primary field of cuspidine. In order to discuss its thermodynamic stability the standard Gibbs energy of formation of cuspidine has been determined by an electromotive force method using CaF2 as solid electrolyte and a transpiration method as follows: The chemical potential diagram and constituent activities for the CaO-Si02-CaF2 system have been evaluated based on the obtained thermodynamic data.

Jan 1, 2003

By James Douglas

A century ago the AIME meeting of 1899 was held at the Palace Hotel in San Francisco California in September. For his presidential address, James Douglas presented this paper which is reprinted in full with the kind permission of the AIME. It presents an interesting comparison relating to events and circumstances in the metallurgical industries at the close of last century. Being on the eve of a new century ourselves, the Editors of this volume of the COPPER 99-COBRE 99 Proceedings considered this paper would be of general interest, hence it is included here. Douglas believed in effective interchange of technical experiences and ideas. He considered the extreme secrecy surrounding the copper works at Swansea, Wales, the world center of copper only years before the time his paper was delivered, as one key reason for its decline, (and eventual closure of all copper plants there). In his paper, the pace of developments in various sectors such as transportation (railroads, the dominant means of I transportation at the time), the iron and steel and copper industries were examined, in much the same way as one might do but on the high technology of today. James Douglas was born in Quebec City, Quebec, Canada and spent his early life there. Forced to move to the United States for family and financial reasons, he went on to become a pioneer in the new Arizona copper industry, and with luck and good judgement with his interest in the new mining properties he also became very wealthy. Douglas was an accomplished mining and metallurgical engineer. He was the first President of Phelps Dodge and helped transform the small trading company of Anson Phelps and William Dodge into a mining giant.

Jan 1, 1999

By Musa Karakus

In an attempt to explain the phenomena of lead entrainment during Cu drossing of lead bullion, two different synthetic lead bullions were heated to 1050°C, cooled slowly to various temperatures, and then quenched. The morphology and composition of dross particles that form when Mn is used to desulphurize bullion also were examined. Polished sections of these pyrometallurgical products were examined by process mineralogical techniques to identify the impurity phases, determine their chemical compositions, examine the morphology of the impurity phases and evaluate the potential for lead entrainment in such crystals, and characterize pre-quench and quench-generated phases. The phases crystallized were metallic lead, metallic copper, galena, chalcocite, albandite, Cu14.4Pb2S9. and 5.5Pb2S3.5. Metallic copper formed isometric skeletal crystals, chalcocite formed platy and skeletal crystals, and 1formed crystals and eutectic intergrowth with chalcocite and Cu14.4Pb2S9 or Cu5.5Ph2S3.5. The pre-quench crystals are larger and usually exhibit skeletal forms; the quench-generated phases are only a few micrometers across and disseminated throughout the lead matrix. Skeletal crystals of metallic copper and chalcocite form three dimensional networks that entrain large amounts of metallic lead.

Jan 1, 1989

By Fujio Ishii

The deoxidation of liquid nickel and nickel binary alloys with silicon has been determined at temperatures between 1500°C and 1650°C using quartz crucibles in order to investigate the deoxidation of nickel based alloys. The equilibrium constant of the deoxidation reaction in liquid nickel and the effects of the different alloying elements such as chromium, molybdenum, tungsten, iron, cobalt and coppcr on the activity coefficient of oxygen in liquid nickel have been established.

Jan 1, 1993

By Shengli Wu, Mingyin Kou, Laixin Wang, Zhe Wang, Xinliang Liu

The sticking behavior of iron ores in the shaft furnace is one of the most important problems in the COREX melting progress, which directly influence the smooth operation and productivity of shaft furnace. Therefore, it is of great importance to study the sticking behavior of pellets in COREX shaft furnace. The results showed that porous metallic iron produced at the interface of pellets samples was the main reason for the sticking of pellets in the COREX shaft furnace. The SI (sticking index) and metallization rate increased with the reduction temperature and gas flow, and decreased with melting rate. However, the SI of pellets in the COREX shaft furnace could be decreased by the proper match of melting rate and reduction temperature, reduction temperature and gas flow, while the metallization rate of pellets were kept at a certain level. Furthermore, the matching of melting rate and reduction temperature was more effective than the matching of reduction temperature and gas flow.

Jan 1, 2016

By Xi Dai

The LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode materials for Li-ion battery were synthesized with Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) as Fe sources by high temperature solid-state reaction method. The Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) materials were produced by liquid co-precipitation method and crystal structure and morphology of cathode materials were characterized by X-ray diffraction and scanning electron microscopy. The composition contents and charge-discharge performances were measured by chemistry analysis and charge-discharge apparatus. The XRD patterns showed that LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode material samples were well-crystallized homogeneous olivine-type phase, with only tiny trivalent iron impurities according to chemistry analysis results. Charge-discharge test showed that cathode materials possessed excellent charge/discharge capacities, about 150mAh/g at 0.1C rate and more than 120mAh/g at 0.4C rate. The polarization of cathode in charge-discharge process can be restrained effectively, for the potential offset between oxidative peak and reductive peak of doped LiFePO4 material was only 0.079V, lower than pure LiFePO4 markedly.

Jan 1, 2006

By K. W. Cathrine Solem

Filtration of liquid aluminium is widely used in the industry for the removal of inclusions, and Ceramic Foam Filters (CFFs) are often the filtration media of choice. It is known that PH3 (phosphine) can be released from used phosphate bonded CFFs when in contact with water. Additionally, there is a need of an improved understanding of the thermal stability and the chemical reactivity of these types of filters, as there is limited information available in the public domain. In the present preliminary study, three CFFs, i.e. Substrate 1–3, with varying AlPO4 (aluminium phosphate) content were studied under controlled conditions. Samples of the substrates, as produced and in contact with 5N pure aluminium, were heat-treated in a vacuum induction furnace at 850 °C and 1300 °C, as well as thermally studied at 850 °C using a Differential Scanning Colorimeter connected to a Thermogravimetric Analyser (DSC-TG). All tests were performed under an inert atmosphere of argon (Ar). Mass changes of ∼0.001 % were registered for the pure substrates, and 0.003-0.10 % when in contact with aluminium. In the latter case, diffusion of P (phosphorous) from the bulk of the substrate to the interface was established to have taken place. A colour change, from white to orange/brown, was also observed at the interface, which is a clear sign that a chemical reaction has taken place. As a result, the thermal stability of the substrates can be questioned under present conditions.

By Wantae Kim, Jaechun Lee, Tatsuya Oki, Sungbaek Cho, Sangbae Kim

"Effect of attrition scrubbing on the recovery of platinum group metals(PGMs) from automotive catalytic converter was discussed. The attrition scrubbing as comminution and separation process was effective for the recovery of the catalyst layer, ?-alumina, from ceramic supporting matrix, cordierite, by physical impact and shearing action between particles in the scrubbing vessel. The catalyst layer was dislodged from the surface of the supporting matrix into fine particles less than 45µm by attrition scrubbing. The production of fine fraction less than 45µm increased as the residence time for attrition scrubbing increased. The fine fraction obtained at the residence time of 40min contained 19.25% CeO2, 1.93% ZrO2 and 418.8ppp PGMs. The recovery of ?-alumina in the fine fraction increased as the residence time increased. Simultaneously, the recoveries of CeO2, ZrO2 and PGMs increased and reached up to 82.9% CeO2, 78.7% ZrO2 and 78.9% PGMs at the attrition scrubbing time of 40min. The production of the fine fraction and recovery of ?- alumina increased when the solid concentration and initial feed size increased.IntroductionThe automobile catalytic converters contain appreciable amount of PGMs. Currently several million tons of used catalytic converters are disposed annually worldwide, each containing about 0.5-1g of platinum and 1-2g of all PGMs1). The recovery technologies of PGMs from spent catalytic converters have been thoroughly reviewed by numerous researchers since last decades. Two types of methods, wet and dry processes, have been commercially operated. In the wet process, the PGMs on the spent catalytic converters were dissolved mostly in the form of chlorocomplex, MCl6 2-, by contacting with aqueous solutions. Subsequently the resulting solutions are treated to concentrate and the precious metal ions are reduced by introducing metals such as Al, Fe and Zn in the concentrated system2). In the dry process, the spent catalytic converters are melted, in some case with CaO, at an elevated temperature to produce a low viscous slag. The PGMs in the melt are separated by allowing them to adsorb on Fe or Cu having high specific gravity7). Although highly pure precious metals could be obtainable, the recovery technologies of PGMs currently operated seem not to be cost-effective since PGMs embedded in these types of catalytic converters are present in very small quantities."

Jan 1, 2008

By Sang Han Son

The vapor pressures of FeCL2 and ZnCL2 in the FeCL2?ZnCL2 system were measured by the transpiration method at 873K and 9I7K, The vapor pressure data were interpreted to indicate the formation of complex ions in the FeCL2?ZnCL2 melts, It is presumed that the complex molecule FeZnCl4 as well as FeCL2 and ZnCL2 exists in the vapors in equilibrium with molten FeCL2-ZnCL2 mixtures, The activities in the FeCL2-ZnCL2 system are shown a negative deviation from Raoult's law. These results suggest the formation of complex ions such as ZnCL14 in molten FeCI2?ZnCL2 mixtures.

Jan 1, 2003

By W. K. Connor, O&apos

The Bureau of Mines has conducted beneficiation, carbothermic reduction, and leaching tests of Mn oxide ores as part of its evaluation of the Mn and Co resources of the West- Central Arkansas District. The major Mn oxides in the ore include cryptomelane, psilomelane, pyrolusite, and lithiophorite. Cobalt is contained within the Mn oxides. Nonbeneficiated ore was reduced at 800' C with coal and leached in ammonium sulfate and ammonium carbonate leach liquors. Ore concentrates were calcined at 600" C prior to reduction under the same conditions as the raw ore. Head analyses reported up to 21 ptt Mn and 0.11 pct Co. Extractions of 70 to 90 pct Mn and 40 to 60 pct Co were achieved.

Jan 1, 1992

By B. Nowak

For sources with an iron-to-vanadium ratio of far above 1, it is proposed to leach in acid and to oxidize under autoclave conditions. During this oxidation process, it is experimentally shown that divalent iron contained in this solution will be oxidized to trivalent iron, whereas free acid contained will be consumed by this reaction. In case no acid is present or already fully consumed, a solid consisting of ferric compounds and an iron-vanadium-co-precipitate will form that can be filtered from the solution. If choosing the right reaction conditions, this filter cake has an iron-to-vanadium ratio of close to 1, whereas the liquid remainder is almost vanadium free. This precipitate, identified as FeVO4, 1.1 H2O, can be processed by conventional technologies such as caustic leaching, or probably salt roasting or reduction with aluminum, yielding common marketable products.

By Daguang Lu

The section of sintering and BF (blast furnace) is very important in iron-making process. In practice, the scheduling is so extensive that three faults unfavorable to continuous product will be easier to happen. This paper introduces the integration Petri Net and GA (genetic algorithm) as suitable tools for simulation and optimization of scheduling to section of sintering- BF under a certain hot iron or-der. The situation of the iron plant Chongqing Iron and Steel Company is researched in approach above mentioned. By analysis, the conclusion is drawn that scheduling with optimized values can maintain continuity of key operations , can satisfy order of hot iron in maximal degree and can keep the best stability of key storages.

Jan 1, 2009

By Gordon Lewis

A complex mixture of hydrated reaction products is obtained from hydrothermally treated refractory cements and castable concretes. TGA can be used both to identify the product phases in the mixture and to determine a quantitative relationship among the phases. When reacted mixtures contain compounds that decompose simultaneously, or nearly so, additional assumptions must be introduced in order to develop a quantitative phase analysis. It is the purpose of this paper to examine some of these assumptions and to demonstrate their application, particularly to refractory cement systems.

Jan 1, 1982

By Kimio Itagaki

The distribution ratios of Ag, Pb, As, Sb and Bi for the Cu2S-FeS or Ni3S2-FeS matte / FeOx SiO2, FeOx-SiO2-CaO or FeOx-CaO slag equilibration in a MgO crucible were determined experimentally at 1523~1573K under controlled partial pressures of S2 and O2 at given PSO2 of 10.1, 50.7 and 101.3 kPa (0.1, 0.5 and 1 atm) and be observed dependency of distribution ratio on the matte grade, SO2 pressure and slag basicity were analyzed on the basis of thermodynamics,

Jan 1, 2003

By R. Boom, B. Kraaijveld, H. Kuntzel, Y. Meteleva-Fischer

"Alloying refining with rare earth elements followed by acid leaching was examined for the potential of upgrading of metallurgical grade silicon. Microstructure study of silicon alloyed with small additions of rare earths showed behavior relatively similar to the influence of calcium addition. After alloying with neodymium the phosphorus content was detected in various intermetallic silicides containing neodymium and iron. The content of lanthanum and neodymium in refined silicon was by several times lower than that of aluminium and calcium. Alloying with lanthanum and neodymium at smaller additions than calcium reduced the phosphorus content down to the same level. The efficiency of lanthanum and neodymium in removal of boron and phosphorus at the 1-2 wt% of their additions and their low solubility in silicon make the alloying with these metals followed by acid leaching an attractive option for the refining route of metallurgical grade silicon up to solar grade.IntroductionA striving for a cheap ""green"" energy directs the research interests in silicon solar cells towards new efficient refining routes for metallurgical grade silicon (MG-Si, -98% purity). The silicon price determines up to high extent the solar module's price, so that cheap and efficient metallurgical process is awaited. The research challenge is to fulfil the purity requirements of solar grade silicon (SoG-Si, 6N) by competing with the energy-consuming and environmentally unfriendly Siemens process. Most difficult impurities to remove are boron and phosphorus, so technologies dedicated to their efficient removal attract an attention of industry and academia.Alloying refining (also known as solvent refining) is one of the most promising refining options, which is based on a principle of solid-liquid extraction using limited solubility of impurity elements in solid silicon [ 1]. Various elements were proposed for alloying refining: aluminium [2], calcium [3], tin [4], iron [5], copper [6] etc. The attractiveness of the alloying refining is in decreasing a melting point of the metal mixture and an affinity of the alloying element to the most harmful impurities, especially to boron and phosphorus. However, the difficulties are still faced due to self-solubility of the alloying elements, their low affinity to boron and/or phosphorus, silicon losses and necessity of removal of the silicide impurity phases in an additional step, using acid leaching [7], fractional melting [ 8] etc."

Jan 1, 2013