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By O. Kitamura, H. Kubota

The Harima Works started its ISP operation in 1966 and been expanding its production capacity from 3,000 tonne Zn/month and 1,500 tonne Pb/month to 7,500 tonne Zn/month and 2,500 tonne Pb/month. It is not only treating zinc, lead and bulk concentrates but also secondary materials like Waelz kiln oxide from the Shisaka Works of Sumitomo Metal Mining, waste treatment sludges, industrial wastes and others. Its final products cover Prime Western Grade (PWG) zinc, Special High Grade (SHG) zinc, continuous galvanizing grade zinc, electrolytic lead, cadmium, indium, thallium and sulfuric acid. This paper briefly describes the smelter's historical and present operations. The key data for the current impurity control management and for the distribution of impurities such as copper, iron and arsenic are presented.

Jan 1, 2000

By Linda C. White

The use of red mud, a waste product of the ?Bayer? process for bauxite refining, was investigated for its arsenic removal effectiveness from aqueous solutions under various conditions. Red mud efficiently removed As(III) between a pH range of 7.6 and 9; and As(V) in the pH range between 5.5 and 6. Pre-washing of the red mud with salt water considerably improved its arsenic adsorption capabilities. With appropriate red mud dosage, the residual arsenic in solution was decreased below the regulated acceptable arsenic limit (0.1 mg/L) from aqueous industrial wastes. The arsenic adsorption followed first-order rate kinetics and fitted the Langmuir isotherm model. Results suggest that red mud is potentially a useful adsorbent for removal of arsenic from contaminated water or industrial waste solutions.

Jan 1, 2003

By T. T. Chen

Gold in the Twin Creeks ore is primarily associated with arsenian pyrite. During pressure oxidation, the sulphides are solubilized, but part of the dissolved iron reprecipitates as jarosite and as an iron sulphate-arsenate-phosphate phase. The pressure oxidation products are subjected to cyanide leaching. The cyanide leach residues consist of quartz, gypsum, bassanite, anhydrite, small amounts of jarosite, an iron-sulphate-arsenate-phosphate phase, as well as trace amounts of orthoclase, rutile, pyrite, hematite and monazite; all these particles are dispersed in a fine grained matrix of illite-muscovite. The autoclave leach residues contain a small amount of carbonaceous matter. Many gold grains are detected on the surfaces of the carbon particles, and these gold particles are not leached during cyanidation. The gold particles are typically 0.1-0.2/Lm in size and commonly are embedded in the carbon surface or are coated with a K-AI-Si-S-O phase on the surface of the carbon. The gold grains are consistently associated with elevated CI contents (50-300 ppm Cl). The poor gold cyanide leach recoveries, which initially occurred in the Twin Creek developmental circuit under certain operating conditions, are attributed to the presence of chloride in the feed. This results in the formation of soluble gold chlorocomplexes in the autolcave and the subsequent sequestering of the gold on the surfaces of the carbon particles.

Jan 1, 2000

By P. Regan

Following the introduction of the Contilanod process over 10 years ago at Copper Range and IMI Refiners, significant changes and advances have been made to this pioneering anode production technique. A new radial flow metal feeding concept has been developed that allows a substantial increase in casting rates on the Hazelett® twin-belt caster. To cut the 45 mm thick continuous anode plate into shaped anodes at rates of 100 t/h or more, a filly moving hydraulic shear designed by Mannesmann Demag has replaced the slower speed plasma cutting torch. Details of the.new caster and shear are presented along with operating results from the new lines starting up in 1999 at the Gresik smelter/refinery in Indonesia and the completely revitalized Mansfelder Kupfer und Messing complex in Germany.

Jan 1, 1999

By M. I. Hoschke

The viability of pyrometallurgically treating zinc containing materials is enhanced by recovering zinc metal rather than oxide from furnace gases. During the history of zinc production, there has been continuing development on methods of recovering zinc metal that has resulted in three commercial designs in use today. The most widely used commercial technology, currently producing 13% of the world's zinc, is the lead splash condenser which is attached to the Imperial Smelting Furnace (ISF). The other remaining commercial designs are the zinc splash condenser and the Wheaton-Najarian vacuum condenser. The need to treat increasing quantities of secondary zinc materials, particularly Electric Arc Furnace (EAF) dust, has renewed emphasis on the development of ways to recover zinc metal. Development work in this area has proved to be difficult. Partly as a response to these difficulties, studies into the fundamentals of zinc condensation and absorption have been undertaken. Pasminco Research Centre (PRC), Newcastle, is also developing a. new zinc absorber to recover zinc metal from furnace gases:. The design attempts to address the problems associated with current devices.

Jan 1, 1994

By M. Sahoo

The development of new alloys containing bismuth and selenium for potable water supplies are reviewed. The new alloys are replacements for the leaded red- and semi-red brasses by the low-lead alloys, SeBiLOYS I and II, for sand casting, and SeBiLOY III replaces the lead containing yellow brass, C85800, for permanent mold casting. As the new alloys use bismuth and selenium, the supply and demand of these elements are discussed. The key casting characteristics discussed are: tendency to dross formation, freezing range (liquidus and solidus temperatures), fluidity, resistance to hot tearing, microstructures, mechanical properties, machinability, grain refinement and corrosion behaviour.

Jan 1, 1999

By Sven Eck, Andreas Ludwig, Menghuai Wu

"Phase separation is a frequently occurring phenomenon during solidification accompanied by melt convection, sedimentation or, in the case of two unmixable liquids, a Marangoni driven motion. In order to describe these phase separation phenomena a two-phase volume-averaging model was employed for globular equiaxed solidification of binary alloys and decomposition and solidification of hypermonotectic alloys. The model considers nucleation and growth of equiaxed grains or second phase droplets, motion and sedimentation of grains or droplets, feeding flow and solute transport by diffusion and convection. It allows the prediction of macro segregations and the distributions of grain size or droplet size. Evaluations were made by comparing the numerical predictions with experimental results. For example it is shown that the numerically predicted grain size distribution in a plate casting (Al-4wt%Cu) agrees reasonably well with the experimental analyses.IntroductionModeling of metallurgical processes is a rapidly expanding field and the research activities in the last decades cover a wide range of areas including melt pre-treatment, solidification and subsequent manufacturing routes. Among those activities solidification stands in the central position, because the primary structure of the materials, and even many defects such as porosity, (macro or micro) segregation and inclusions form during solidification. Those primarily formed structures or defects once existing are difficult to be removed or modified by the subsequent material processing.Solidification is a multi-disciplinary field involving thermodynamics, fluid dynamics and solid mechanics, heat and mass transfer, and other disciplinesr1 -31• One of the most challenging problems in solidification modeling is the complex interactions between physical phenomena occurring on different length scales ranging from atomic rearrangement over single crystal-melt interactions to heat extraction, momentum and species transport at the system level. Modeling an industry process on atomic scale is umealistic, even on grain scale (e.g. phase field method) it would need another 40 years to be able to model the exact grain morphology in a casting space envelope of 10x10x10 cm3 [ 4]. Therefore, the realistic models for industry process are based on the solution of the macro transport equations (mass, momentum, enthalpy and species) on system scale. The microscopic phenomena such as thermodynamics, nucleation law, crystal growth kinetics and interactions at the liquid-solid interface are considered with simplified models, which are coupled with the macroscopic transport equations."

Jan 1, 2004

By Yutaka Shiraishi

Two methods were developed to measure the viscosity of the slag from the glassy to the liquid states in an ascending temperature process. The first method employs rotating parallel plates within which is placed a solid cylindrical sample in line with a sphere. The second method uses a tube which is pushed into a sample held in a rotating crucible. Both methods were tested using standard glasses, including boron trioxide and NBS standard glass #711. The main difference between these two methods is in sample preparation. Comparative measurements between two methods were performed using a sodium boro-disilicate glass containing 5%mol of alumina. The results showed good agreement in the mid-range of glassy viscosities, 105 to to7 Pa.s. In the liquid state, there were no significant differences between the two methods.

Jan 1, 2003

By Alan DonaldsoN

Plasma Quench production of titanium is the thermal dissociation of titanium tetrachloride into gaseous titanium and chlorine followed by rapid quenching to prevent back reactions. Titanium tetrachloride dissociates into titanium and chlorine atoms at 5000 K. Expansion through a Delaval nozzle accelerates the gas to supersonic speed cooling it very rapidly. Cooling rates are as high as 7exp 1 0 Kelvins per second. Injected hydrogen reacts with condensed titanium particles to form titanium hydride and with the chlorine to form hydrogen chloride. We have produced titanium powder at 20 kglh in a continuous reactor. Costs are projected to be lower than the Kroll Process at large enough scale. Most of the cost reduction would result from elimination of magnesium as a reducing agent and much lower capital costs.

Jan 1, 2001

By A. V. Tarasov

The nonferrous metals industry has been a sector with one of the highest growth rates during the recent years. The prospects for the Russian metals industry during the period until 2010 are associated first of all with a growing domestic demand for its products. The technological level of the metallurgical operations in Russia is relatively low in comparison with industrially developed countries: the average energy requirement is higher by 20% to 30%; the amount of generated waste in the process of rolled products manufacture is twice as high; the average labor productivity is lower by 2.5 to 3.0 times; the overall negative environmental impact is twice as high. Improvement of the technological level of the nonferrous metals production under the conditions of market economy is possible by application of innovative technologies for the development of this sector. The main trends for development of the nonferrous metals sector are: - meeting of more stringent requirements to the quality of concentrates; - more complete recovery of associated elements as commercial-grade products; - development of continuous process lines based on autogenous, resource-saving and environmentally safe processes; - use of combined technologies, including pyrometallurgical, hydrometallurgical and upgrading processes; - expansion of the fields of application for nonferrous metals and their alloys.

Jan 1, 2006

By Donna M. Noel

Bacterial strains have been cultivated from solids previously exposed to cyanide that will tolerate 300 ppm sodium cyanide under anaerobic conditions. In selected solid samples, these bacteria have been shown to reduce the level of cyanide from approximately 300 ppm to essentially zero in about 50 days under anaerobic conditions. Various media were investigated, and the nutrients providing maximal growth were ?established .. Degradation of cyanide in sterilized solids was determined for comparison with degradation obtained in bioactive solids. All experiments were conducted at ambient temperature and initial pH of approximately 10.5.

Jan 1, 1991

By Xiang Lan

A strain of Thiobacillus ferruuxidans No. 8 was isolated from the acidic mine water of an arsenopyrite deposit, South China. It has been found from the experimental results that the growth of bacteria was inhibited by flotation agents. The order of toxic effect of different flotation agents on the growth of Thiobacillus ferrooxidans is ethyl xanthate > butyat ammonium aerofloat > butyl xanthate ? isobutyt xauthate >? flother No. 2 oil. The bioteaching treatment of arsenic and antimony-bearing gold concentrate in Longshan mine, Hunan province, China, was influenced considerably by the presence of flotation agents. The possible causes of the influence of flotation agents were discussed and an improved method was suggested.

Jan 1, 1991

By D. I. Chalmers

The Brockman rare-metals and rare earth resource is located within volcanic and volcanogenic sediments of the later Proterozoic Halls Creek Group in the East Kimberley region of Western Australia. Exploration including surface trenching, percussion and diamond drilling has defined a major resource of rare-metals and heavy rare earth elements. The host&apos; is a steeply dipping ash-flow tuff, described informally as the Niobium Tuff, enriched in zirconium, hafnium, yttrium, niobium, tantalum, rare earth elements, gallium and beryllium. The mineralization is fine- grained (<20 micrometres) and is the result of alteration and re- mobilization of comparatively simple precursor minerals such as columbite and zircon by fluorine-rich deuteric solutions that were retained in the tuff following eruption. The ultra fine-grained structure of the tuff precludes mineral liberation and separation by physical methods. However, values can be converted to water soluble sulphates by reacting with concentrated sulphuric acid at 250°C. The solution containing aluminium, niobium, tantalum, zirconium, hafnium, yttrium, rare earths and gallium can then be processed to pure products in a sequence of solvent extraction and ion-exchange steps. As a result of these processing techniques, the commercial products obtainable from the resource include mixed rare earth and yttrium concentrates, zirconium-hafnium concentrate, niobium-tantalum concentrate and ceramic grade alumina. Further separation could result in high purity products suitable for ceramic and electronic applications.

Jan 1, 1992

By Wilky Desrosin, Alicia E. Ares, Carlos E. Schvezov

"In the present research the horizontal directional solidification Zn-Sn alloys (Zn-4wt. %Sn, Zn- 6wt. %Sn, Zn-10wt.%Sn and Zn-30wt.%Sn) was carried out by extracting heat in two opposite directions. For this purpose, ceramic molds, a muffie, a horizontal furnace with two heat extraction systems at the ends, a measurement, acquisition and recording temperature system, eight K-type thermocouples and an electronic recorder were used. The main parameters involved in the columnar-to-equiaxed transition, CET, were: the moment of start and end of solidification at each position under consideration, cooling rates, the average temperature gradients and critical temperature gradients at the CET, the average speed of liquid and solid interphases left and right, advancing in opposite directions. Also, solidification kinetics was found to be different between horizontal solidification two-way heat extractions, with preliminary results of the vertical unidirectional solidification. In the solidification experiments, the velocity and accelerations of the liquidus and solidus interphases usually occurs at the end solidification zone of the samples.IntroductionSolidification of metal alloys, which starts in the external equiaxed region (chill), results in two basic types of structures in a single solidified alloy sample: columnar and equiaxed. The presence of both structures indicates the occurrence of the colunmar-to-equiaxed transition phenomenon[!].Studying the colunmar-to-equiaxed transition, CET, is of great technological interest for the evaluation and design of the mechanical properties of the solidification products. To this end it is necessary to understand the mechanisms by which it occurs. As found in previous studies [2-5], the CET occurs by competition between columnar and equiaxed growth. Mainly is controlled by the parameters of casting, such as the alloy composition, the density of the present nuclei in the liquid, the cooling capacity of the metal I mold, and the degree of convection in the liquid [7-10]."

Jan 1, 2014

By George S. Dulikravich

An advanced semi-stochastic algorithm for constrained multi-objective optimization has been adapted and combined with experimental testing and verification to determine optimum concentrations of aJ10ying elements in heat-resistant and corrosion-resistant H-Series austenitic stainless steel alloys. The objective was to simultaneously maximize a number of alloy&apos;s mechanical properties. This research will result in a rigorous tool for the design of high-strength H-Series steels and other types of alloys unattainable by any means existing at the present time. Such a material-by-design tool will also be able to reduce or minimize the need for the addition of expensive elements such as Cr, Ni, Co, Nb, Ti, V, etc. and still obtain the optimum properties of an aJ1oy.

Jan 1, 2003

By Pengfu Tan

In order to understand and control the formation of dioxins and furans in iron ore sinter plants and to possibly avoid expensive end-of-pipe removal stages, thermodynamic calculations on the stability of PCDD/Fs have been combined with sinter process modeling by means of kinetic simulations and computational fluid dynamics. Three thermodynamic databases of PCDD/Fs, derived using the Group Additivity approach and two computational molecular modeling methods, MNDO and PM3, respectively, combined with the SGTE database have been used to model the PCDDIF formation and the PCDD/F isomer distributions in iron ore sintering. The results show very similar conditions for the PCDD/F formation using the different databases. Concerning the isomer distributions of toxic PCDD/Fs, the calculated data derived from the MNDO method showed optimum agreement with measured values from industrial furnaces. The thermodynamic calculations also proved that the isomer distributions found in combustion processes are equilibrium values, while the concentration ratio of PCDDs and PCDFs in the wind boxes does not represent an equilibrium state. A CFD model of iron ore sintering was developed including the kinetics of 15 relevant chemical reactions with the aim of describing the temperature fields and the gas flow patterns in the sintering bed. On the basis of these information and experimental observations reported in the literature possible pathways for the PCDD/F formation in sinter plants have been identified: PCDD/Fs are formed in the critical temperature region of 250 to 450°C below the combustion zone, are then carried downwards with the gas and condensed close to the bottom of the sinter bed. Transported to the discharge end with the solid mixture, they are again released into the gas phase when the flame front approaches the bottom. PCDD/Fs are also formed in the last wind boxes when the hot off-gases cool down and reach the critical temperature range. Consequently, methods to reduce the dioxin formation reactions are proposed including inhibitor addition to the sinter feed and off-gas quenching.

Jan 1, 2003

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 Vladimir Panjkovic, Ostrovski. Oieg, Campbell Cripps Clark, John Truelove

"Effects of properties of raw materials and blast on the performance of an iron bath reactor have been examined by a mathematical model. The model consists of three modules: 1) chemical reactions in the gas phase and heat transfer from gas to droplets ejected from the bath; 2) heat losses from the vessel and radiative heat transfer from the freeboard to the bath; and 3) heat and mass balances for the bath. The following parameters of the process are calculated: coal, ore, flux and oxygen consumption, post-combustion ratio and heat-transfer efficiency, temperature and composition of the off-gas, and slag and metal chemistry.IntroductionOne of the anticipated advantages of smelting reduction over conventional ironmaking is the use of lower-grade raw materials. In this work, the effect of-properties of raw materials on the performance of an iron-bath reactor is examined with a numerical model. The model is also used to assess the effect of properties of the blast (flowrate, temperature and oxygen enrichment) and ejected droplets (generation rate, size and ratio of total weights of slag and iron droplets) on the key parameters of the process. In the process coal, oxygen, ore (which may be partly prereduced) and fluxes for specified slag composition are charged to the bath. Slag and iron droplets are ejected from the bath into the gas phase, where they are heated before returning to the bath. Iron droplets undergo decarburisation and reoxidation with CO2 and H2O. Dust is also generated from the bath, and oxygen or preheated air for post combustion is injected from the top of the vessel.The model consists of three modules: 1) reactions in the gas phase and heat transfer from gas to droplets ejected from the bath; 2) heat losses from the vessel and radiative heat transfer from the freeboard to the bath; and 3) heat and mass balances for the bath. The structure of the model and the data exchange between the modules are shown in Fig. 1. The following parameters of the process are calculated: coal, ore, flux and oxygen consumption, postcombustion ratio (PCR), heat transfer efficiency (HTE), off-gas temperature and composition, slag and metal chemistry, and rates of decarburisation and reoxidation of the iron droplets."

Jan 1, 1996

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&apos; 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 Jonkion M. Font

As a comprehensive contribution to the understanding of oxygen-blowing of matte smelting, the copper and nickel solubilities between the FeOx SiO2-MgO slag with saturated SiO2 and the Cu2S-Ni3S2 FeS matte with the NCu/(NcU+NNi) of 1, 0.75, 0.5, 0.25 and 0, in a MgO crucible were investigated at 1573 K under controlled partial pressures of SO2 at 0.1, 0.5 and 1 atm. The partial pressures of SO2, S2 and O2 were controlled by using an Ar-SO2-S2 gas mixture after passing through a sulfur reservoir. It was clarified that, at a given matte grade, the solubility of copper in the slag was independent of pso2 while that of nickel increased with increasing pso2. This notable difference was considered to be ascribable to the chemical formulas of the mono-metallic sulfides in which one copper atom combines with ½ sulfur atom while one nickel atom combines with 2/3 sulfur atom. It was also clarified that, at a given iron content in the matte, the pot and ps2 were independent of the matte species. This was ascribable to aFeS in the matte, which was independent of the matte composition, Ncu/(Ncu+NNi), at a given iron content in the matte.

Jan 1, 1999