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By Milton Blander

A review of concepts and theories for predicting thermodynamic solution properties of multi- component high temperature liquid solutions is reviewed. During the last 50 years the ability to predict :such properties for molten salts, silicates and metals based on the generally known properties of the lower order (often binary) systems has been developed and shown to provide predictions which are quite useful in science and technology. There are many gaps in our understanding of these high temperature solutions, especially for metals, and considerably more work is needed.

Jan 1, 1996

By Duan Xin-hui, Wang Xin, Peng Jin-hui, C. Srinivasakannan, Zhang Li-bo

The work attempts to optimize the process of preparation of modified semi-coke from semi-coke using phosphoric acid (H3P04) as the activating agent using the response surface methodology (RSM). The influences of three major dependent variables, the impregnation ratio, activation time, and activation temperature were assessed on the independent variables yield and the iodine number. The empirical relationship between the dependent and the independent variables were established using the quadratic response surface models, which were utilized to optimize the process parameters. The significance of each of the parameters and interaction among the parameters on the independent variable was assessed based on analysis of variance (ANOVA). The process variables were varied within the range of impregnation ratio (IR) from 1.5 to 4, activation time from 30 to 90 min and activation temperature from 550 'C to 650 'C. The optimized process conditions were estimated to be an IR of 2.29, activation time of 32 min, and an activation temperature of 605°C respectively using the process optimization tool. The BET surface area of modified semi-coke of the optimized sample was estimated to be 915m2/g, with the pore volume of0.71cm3/g, with an average pore diameter of 3.09 nm, with micropore volume fraction being 52.36%. The scanning electron microscope (SEM) images were utilized to visualize the surface pore structure.

Jan 1, 2013

By A. E. M. Warner

Inco Limited has long and extensive experience in converting nickel-copper primary smelting mattes over a broad range of nickel/copper weight ratios and combined nickel-copper-cobalt contents. At the Copper Cliff Smelter, the composition of the converter product matte has to meet the requirements of the matte separation process; at the Thompson Smelter, converter matte of a different composition is cast into anodes for nickel electrorefining; and in Soroako, Indonesia, a very low copper product matte is granulated for the Japanese market. Recently, Inco has conducted pilot plant testing of three possible nickel-copper matte continuous converting routes, namely flash converting, oxygen top blowing-nitrogen bottom stirring, and tuyere blowing. This test work has generated substantial new information on nickel-copper matte converting chemistry. This overview paper reviews the metallurgy of nickel-copper matte converting, in particular the behaviour of cobalt and the operating conditions required to meet the iron and sulfur specifications of the product matte. The relevant thermodynamic information is used to discuss the industrial data.

Jan 1, 2003

By Cong Wang, Kexin Jiao, Yongan Zhao, Haibin Zuo, Jianliang Zhang

Traditional refractory materials for blast furnace hearth lining are mainly composed of carbon bricks and the ceramic cup. However, these materials can’t meet the demands for long service life design of blast furnaces. In this paper, a new refractory called carbon composite brick (CCB) was introduced, which combined the advantages of carbon bricks and the ceramic cup. In this case, the resistance of the CCB against corrosion was equal to the ceramic cup and the thermal conductivity of the CCB was equal to carbon bricks. From the results of more than 20 blast furnaces, the CCB could be well used in small blast furnaces and large blast furnaces. In the bad condition of low grade burden and high smelting intensity, the CCB gave full play to the role of cooling system, and effectively resisted the erosion of hot metal to improve the service life of blast furnaces.

Jan 1, 2015

By Takeshi Nagano

"Prior to discussing future trends of non-ferrous metals smelting and refining, the past developments are looked back. Social and economic environments in Japan over the past two decades are reviewed. Technological developments to comply with these environments are explained, taking for examples the cases of the Mitsubishi continuous smelting and converting process and Onahama's jumbo tank system for copper tankhouse. After considering the factors which will influence the improvements in non-ferrous processing, future trends are forecasted generally for copper, zinc, lead, aluminum and rare earth metals. Recent development works in Japan for the future are also introduced. In the discussed area, it appears that the emergence of new innovative processes would be difficult. The progress will be made rather toward the sophistication of the existing technologies, utilizing the advancement of the related technologies such as computers, electronics, etc. IntroductionThis paper discusses the future trends of non-ferrous metals smelting and refining on the occasion of the international symposium, ""The Metallurgical Processes for the Year 2000 and Beyond"".It is considered that the improvement of technology is greatly influenced by the social and economic environments which surround it. From this standpoint, review was made of Japanese case over the past two decades. Various new technologies were developed also in the non-ferrous metal world to comply with the requirements under the above environments. The examples are described in the cases of the Mitsubishi continuous smelting and converting process and Onahama's jumbo tank system for copper electro-refining.After foreseeing the major factors which will affect the technological developments in the future, the trends are forecasted for copper, zinc, lead, aluminum and rare earth metals generally. Some development works in Japan, which will give suggestions for future trends, are also introduced in some detail."

Jan 1, 1988

By G. Van Weert

The pellet reactor was developed approximately 20 years ago in the Netherlands for softening drinking water. Since then, some 35 plants have been built, ranging in capacity up to 8500 m3/h. Applications now also include removal of phosphates and fluorides and the production of metal carbonates and sulphides from waste streams. The pellet reactor consists of a fluidized bed, wherein the process solution is thoroughly mixed with the precipitation reagent at special inlet nozzles to give over-saturation of the compound to be precipitated. In water softening applications, the compound is CaCO,. In the case of nickel or other metal waste streams, Na2CO3 solution is added in sufficient amounts to precipitate metal (hydroxy) carbonate on the fluid bed particles. These grow typically to dense spheroids, which are removed when they reach 0.8 to 1.0 mm diameter. These spheroids are easily dewatered, free flowing and low dusting. The latter property is becoming an attractive advantage in connection with new plant hygiene regulations. The operation of a 60 cm diameter pellet reactor on nickel containing plating waste is described and the properties of the produced nickel carbonate spheroids are discussed.

Jan 1, 1993

By Yanhui Liu, Xuewei Lv, Chenguang Bai

A thermodynamic model for determining the surface tension of molten slag by considering the surface tension and molar volume of the pure oxide component, and their ionic radii was extended to the slag bearing high TiO2 (varying from 80 to 67%) at 1973 K. The iso-surface tension curves for the FeO-TiO2-Ti2O3 ternary system at 1973 K are almost parallel to the FeOTi2O3 line. TiO2 plays a role of surface-active solute, and its surface-active effect is attenuating with increasing the TiO2 content. The iso-surface tension curve shifts away from the TiO2 corner, indicating that the surface tension of the ternary slag decreases along with the addition of SiO2. The reasons include the addition of SiO2 with lower surface tension and the decrease of the total ion moment at the surface. Both CaO and MgO can bring about that the iso-surface tension curve shifts towards the TiO2 corner, indicating that the surface tension of the ternary slag increases along with the addition of CaO or MgO. CaO has a more pronounced effect on increasing the surface tension of the ternary slag than MgO at an equimolar amount addition. The increase of the surface tension results from both the compositional change and the variation of the slag structure.

Jan 1, 2015

By M Philip Schwarz

"This paper reviews the status of computational modelling of a variety of common metals reduction processes, namely the blast furnace, rotary kiln and fluidised bed, and one new process not yet commercialised, namely smelting-reduction as in the HIsmelt Process. In each case, the last decade has seen the emergence of the capability to simulate the processes using multi-phase reacting computational fluid dynamics techniques. In some cases this capability is still in the process of being developed, and the next few years will see the maturing of the modelling techniques. As they become established, it will be possible to apply them to further refine the older technologies such as blast furnaces and rotary kilns, and assist in the optimisation, commercialisation and acceptance of the newer technologies such as fluidised bed and molten bath reduction. The development of a computational fluid dynamic model of bath smelting-reduction is described in some detail to illustrate how a large number of complex and interacting phenomena can be successfully simulated within a CFD framework. IntroductionPyrometallurgical reduction processes, such as the iron blast furnace, have become increasing more sophisticated through the centuries, so that today they are often highly efficient. There are continuing pressures, however, to refine existing processes and develop new ones. The imperatives are often economic, given that the long-term trend in the price of metals is always downward. In recent times, there has been the additional need to improve the environmental impact of metal production. Given that they almost inevitably require the use of carbon, metal reduction processes are large sources of greenhouse gases, and even a relatively small improvement in efficiency can be valuable in reducing CO2 production. Local environmental issues, such as the need to control of particulate emissions, are also driving incremental improvements in equipment.In addition to the economic and environmental drivers mentioned above, new process development is also being driven by the need to process new ores, and the need to produce unrefined metal in a form more compatible with alternative routes for downstream processing. An example of the latter is the production of DR! (Direct Reduced Iron) as a feed for EAF Electric Arc Furnace) in mini-mills.Further improvement of processes that have already been honed by continual plant experimentation over many years is not an easy task. To deliver further gains in efficiency, throughput, or product quality requires a highly sophisticated tool: one such tool· is computational modelling."

Jan 1, 2001

By N. J. Themelis

In the last two decades, the Outokumpu flash smelting process has become the dominant new technology for copper smelting and has? also been applied to the smelting of other metal sulfides. The application of oxygen enrichment and improvements in concentrate burner and furnace design have resulted in ever increasing smelting rates per unit volume of the reaction shaft. This paper examines the. rate phenomena taking place in the reaction shaft of the Outokumpu furnace and compares information obtained from a mathematical model of heat and mass transfer rates to results obtained in pi1ot tests conducted at Pori, Finland, and to actual performance of a number of flash smelters around the world. 2?

Jan 1, 1985

By P. F. Kerr

This is not a conventional professional paper. It deals mostly with personal experiences. These concern a background in applied mineralogy. Your committee asked me to do this. I accepted with a California enthusiasm which has since diminished with the approach of a Chicago winter. Nevertheless, I wish to thank your committee and also to apologize in advance for omissions and inadequate statements, as such a paper must possess. My introduction to applied mineralogy took place in 1922 at Stanford University. Physicists had recently demonstrated that crystalline powders would reflect x-rays in a systematic manner. Professor A.F. Rogers sug¬gested that significant x-ray reflections might be obtained from powdered opaque minerals. With the aid of Professor D.L. Webster in the Physics Department, I constructed an x-ray diffraction outfit. It was a crude affair, but it worked. Starting with 1924, we secured recognizable patterns of a goodly number of ore minerals (1,2,3). Today x-ray diffraction outfits are common, and a card system of mineral identification is constantly used.

Jan 1, 1981

By Florian Kongoli

Non-ferrous smelting slags .can contain magnesia, which substantially increases the liquidus temperature. One option to counter this increase is to flux with calcia. In this work, experimental liquidus measurements including new measurements on industrial slags have been compared with a FACT-based thermodynamic model, which predicts the liquidus surface of multi-component iron silicate smelting slags containing both magnesia and calcia. The predictions, which agree well with experimental results, are summarized in both isothermal and non-isothermal diagrams to give a quantitative description of the liquidus surface.

Jan 1, 1998

By Taiping Lou

The effects of slag composition, additive agents, and heat treatment conditions on the perovskite (CaO ? TiO2) crystal morphology, the precipitation behavior, the crystal growth and the volume fraction (VF) in the Ti-bearing blast furnace slags were investigated. The morphology of perovskite is dispersed dendriform in molten slags. The crystal growth mechanism of the remelting of fine dendrites and the coarsening of larger grains exists throughout the solidification of molten slags. With the temperature decrease, the VF was increased and Perovskite transformed from fine dendrites to coarsening ones or equiaxed grains. The lower cooling rate can increase the VF and coarsen the grain obviously, while higher cooling rate will decrease the VF and reduce the average equivalent diameter (AED) of Perovskite. When .increasing the content of CaO and Fe20}, the VF can increase obviosly. However, high basicity will give rise to the increasing of viscosity of slag, which result in the reducing of the AED. The experimental results showed that additive CaF2 and MnO can efficiently decreased the viscosity of the slags, and obviously improved the morphology of perovskite and promote growth.

Jan 1, 2000

By Michael J. Nicol

Growing environmental and occupational safety concerns about the use of cyanide in gold processing has increased the interest in more acceptable alternatives. The most likely of these is thiosulfate. However, the thiosulfate process lacks a proven in-pulp method of recovering the dissolved gold, because activated carbon is not effective for the absorption of the gold thiosulfate complex .. Anion exchange resins do offer a possible route for in-pulp recovery. This paper describes work aimed at the evaluation of the effectiveness of commercially available anion exchange resins for the recovery of gold from thiosulfate leach liquors? and pulps. It has been found that strong-base resins are superior to weak-base resins in that they have a larger capacity, which assists in reducing the competition from other anions within a leach solution. Further studies with a selected commercial strong-base resin have shown that competing polythionateanions (particularly tri-and tetrathionate). Lower the maximum possible gold loading but that gold is selectively recovered over other base metal anions in solution. Kinetic experiments found that while? competilig anibns did not affect the initial rate? of gold loading it was important to minimise the contact time of the resin in solution so to prevent displacement of loaded gold by competing anions over longer times. A small-scale resin-in-pulp plant investigation showed gold can be recovered from a leach pulp by a strong-base resin to yield gold loadings of 3000 mg/L, barren pulp containing less than 0.05 mg/L of dissolved gold and. copper loadings of 500 mg/L. Loaded copper was displaced gold and at a loading of 2000 mg/L gold the copper loading was minimal «500 mg/L). The resin was found to recover gold adsorbed on the solids that would, otherwise have. reported to tails if a solid/liquid separation method were used. A patented two-step elution process in which copper and then gold are separately eluted from the resin is also discussed.

Jan 1, 1998

By G. L. Peralta

Geothermal energy is an important source of power in more than 12 countries and is a potential source in 50 countries. However, the exploration and use of geothermal resources generate residues such as scale and sludge. The scale is from the steam distribution pipes while the sludge is from cooling ponds. These solids contain significant levels of elements which are of environmental importance notably, arsenic, sulfur, copper, zinc and lead that require safe treatment and disposal. The compositions, phases, textures, morphologies and size of scale and sludge particles have been studied by laser particle size analysis, light microscopy, scanning electron microscopy, X-ray microanalysis, and X-ray diffraction. In addition, their leachability was tested with protocol leaching procedures and sequential extractions. The detailed spatial relationships and speciation of the environmentally significant constituents have received particular emphasis. The information obtained is useful in understanding how the scale and sludge are formed, their leaching behavior if disposed of in a landfill and in developing appropriate treatment strategies.

Jan 1, 1994

By Reed M. Izatt

SuperLig® materials are capable of individually separating Rh, Pd, and/or Pt in highly purified form (99.95 to 99.99%) from a variety of chloride-based feed streams in a single stage operation. The hydrophillicity and associated kinetics of the supported materials allow for operation at relatively high flow rates of both loading and elution in a packed bed format. Pilot and commercial systems have been operated with Rh, Pd, and/or Pt present in the feed from single digit ppm (mg/l) to tens of g/l. A dual SuperLig® system for one pass Au(CN)2- separation followed by Cu and CN- recovery for CN- recycle has also been tested up to a pilot level,

Jan 1, 1999

By James C. Sever

Two green field magnesium reduction plants are under consideration using dolomite as the raw material. The Calix calciner was independently selected for both plants. The unique design of this calciner is detailed and the advantages defined for the specific application. The low carbon foot print of this unit combined with the ability to capture food grade carbon dioxide makes this an environmentally proactive approach to carboniferous ore calcination.

Jan 1, 2015

By Mitsutaka Hino

The contents of gangue minerals, such as A1203, P205, crystalline water and so forth in the iron ore imported to Japan tend to increase year by year, Though the increments of such gangue contents are approximately 0.1-0.2 mass%, some problems for the blast furnace operation in ironmaking process have already been reported, In order to clarify the mechanism of harmful effect caused by the small increment of gangue minerals, mainly A1203, on the blast furnace operation, the dripping behavior of FetO-CaO-SiO2-AI2O3-MgO slag from the iron funnel, which simulated the micro-porosity in sinter ore, has been observed with the wide range of basicity, Al2O3, FetO and Mgo contents. The effect of MgO on the dripping behavior of slag has been summarized in this paper, It was found that the addition of 2mass% MgO resulted in large increase of hold-up on the most of the conditions. When FetO content was less than 20mass% and the basicity was lower than 0.8, MgO lowered the hold-up even if the slag contained 10mass% Al2O3. Every slag hold-up showed the minimum at the basicity of less than unity on the conditions of constant FetO and A1203 contents. This trend became remarkable when the slag contained 2 mass% MgO.

Jan 1, 2003

By John M. Gaines

Lead concentrates from the Viburnum Trend in Southeast Missouri are sintered, prior to smelting, to bind the particles together, homogenize the feed, and reduce the sulfur content. About 20% of the sinter at some plants is classified as bad sinter. A total of 130 samples of good and bad sinters were studied by reflected light microscopy, scanning electron microscopy-energy dispersive analysis, and electron microprobe analysis to characterize their differences in mineralogy and textures. Good sinters consist predominantly of hardysonite, franklinite, lead silicate matrix, and large crystals of calcium-magnesium-iron silicate, together with minor amounts of lead oxides, lead-zinc silicate, metallic lead, specular hematite, magnetite, lead-iron-bearing zincite, and zinc-lead-magnesium-bearing wustite in a tightly intergrown mesh of crystals and with an evenly distributed porosity of about 15-20%. Bad sinters contain larger amounts of lead silicate matrix, galena, metallic lead, and lead oxides, but smaller amounts of hardysonite, franklinite, and calcium-magnesium-iron silicate, lack intimate intergrowth of the phases, and have lower (0-5%) and unevenly distributed porosity.

Jan 1, 1992

By Eric J. Beckman

Recovery of metals from dilute solution, whether the matrix is solid, or liquid, remains a considerable technical and financial challenge. Methods currently exist whereby metals can be extracted from either type of matrix, yet these methods consume significant quantities of reagents and can also generate multiple waste ,streams in the process. Technology developed in our lab allows efficient application of environmentally-benign CO2 to a number of separation problems involving metals. For example, we have employed biphasic mixtures of C02 and water as a green acid leach medium. Metals have been extracted from a steelmaking process residue and then recovered as metal carbonates through depressurization. In this process, metals are extracted and recovered without the use of reagents other than CO2 and water, and CO2 is sequestered as a solid. In addition, through synthesis of Cal-miscible phase transfer agents, we have shown that CO2 can replace the organic solvent currently used in refining of precious metals, The sensitivity to pressure of phase behavior in a CO2-mixture may allow significant streamlining of the process as well. Finally, CO2 soluble chelating agents have been used to extract toxic metals from acidic effluent such as that found in plating facilities.

Jan 1, 1999

By Richard D. Hangi

Process mineralogy techniques are uniquely applicable to industrial problems related to the extractive metallurgy of nickel, cobalt, and associated metals. Reflected 1ight microscopy, together with selected determinations by scanning electron microscopy-energy dispersive spectrographic analysis and electron probe microanalysis, provides the means to identify the ore minerals cobalt and nickel ores, determine the abundance of each ore mineral, assess the extent of intergrowth between the cobalt and nickel minerals and other ore and gangue minerals in the ores and concentrates, and predict the potential success of cobalt and nickel extraction by grinding, flotation, pyrometallurgical, and hydrometallurgical treatments. In addition, the extent of locking of the cobalt and nickel minerals with each other and with the gangue minerals can be directly observed by reflected light microscopy. Where ores have been treated by hydrometallurgical procedures, reflected light microscopy can serve to determine the causes of excessive leach consumption. Finally, the partitioning of cobalt and nickel between high-temperature synthetic phases produced by pyrometallurgical treatment can be precisely determined by process mineralogy techniques. Case histories from cobalt and nickel deposits illustrate the value of applied mineralogical techniques in the study of cobalt and nickel ores, beneficiation, hydrometallurgial, and pyrometallurgical products.

Jan 1, 1993