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By H. Ikeda

The new Onahama N0.3 tankhouse was put into operation early in 1973. This new tankhouse, which has a capacity of 90,000 metric ton cathode per year, is distinct in many important respects from conventional tankhouses. The major objectives in design were to simplify the construction and ope- ration for reduction of the costs for labor, interest and depreciation and also to reduce the copper inventory in the tankhouse by the use of conti- nuously-cast anodes. As a result, the investment cost was decreased by approximately 30% and the inventory cost by approximately 600, while the production per unit area of the tankhouse was increased by 80 - 100% as compared with the existing conventional-type tankhouses at Onahama. By abolition of cell inspection and maximum mechanization of materials handling the labor cost was decreased by as much as 80%. On the other hand, the new system has some disadvantages, such as increase in anode scrap ratio and increased cost of anode casting. The No.3 tankhouse system is, however, still at its starting point, while conventional methods have been continuously improved over the past years of operation. It is expected that the innovational ideas behind this system will serve as bases for a more efficient electrolytic refining system in future.

Jan 1, 1976

By Pengfu Tan

A thermo-chemical model of the copper P-S converter and a viscosity model for the converter slag have been developed to predict the behavior of magnetite in the converter slag, amounts of slag and matte, compositions of slag and matte, volume of the bath, bath temperature, slag blow endpoint determination, SEMTECH OPC signals, and the viscosity of converter slags. The predictions of bath temperature, slag and matte compositions, and magnetite content in the slag have been validated by the industrial data. The effects of fluxing strategy, returns and skim charges, oxygen enrichment, and temperature on the magnetite formation in the slag have been predicted and discussed. The effect of oxygen potential, SiO2/Fe in slag, detection of slag blow endpoint, and temperature on Fe3O4 content in converter slag, slag viscosity, liquidus temperature of converter slag and skimming operation has been modeled and discussed as well. Some applications of the industrial operations have been presented.

Jan 1, 2009

By Matthias Schnitzler, Herbert Pfeifer, Ralf Bolling

"To transform metals high temperatures are usually needed. A fast and efficient heating can reduce the C02 emitted. The fastest way to heat metals is called direct flame impingement (DFI). The flame impinges upon the item being heated. For this method it is important to know the shape and length of the flame. Laser-induced fluorescence (LIF) technology allows measurements of a two-dimensional field without influencing the reaction or the flow. Commonly used is the measurement of OH-radicals, an indicator of the reaction zone.In the presented study measurements of a turbulent diffusion flame are shown. The position of the reaction zone and the influence of the distance between the item being heated and the burner are investigated. Conventional measurements and LIP-measurements are compared and the potential of DFI to increase the efficiency of heating metals is discussed.IntroductionDuring industrial heating processes a fast and efficient heating technology is required. Two important aspects are the NOx emission and the energy efficiency. The direct flame impingement (DFI) technology has the highest heat transfer rate possible with a gas/air flame. The turbulent high velocity flame jet impinges upon the item being is heated [ 1]. Due to the high heat transfer rate furnace and exhaust gas temperatures are lower. Therefore the energy efficiency is increased and the amount of NOx emitted is reduced.Hydroxyl- (OH-) radicals are an intermediate product that is generated during the combustion of hydrocarbons [2]. They are commonly considered as an indicator for the reaction zone and position of heat release. Figure 1 shows the hydroxyl-mole fraction in dependence of the distance along the gas flow. The figure clearly shows how fast the OH-concentration increases in the reaction zone. Figure 1 also shows that OH-radicals are present in the post combustion region, however in smaller concentration [3].The laser-induced fluorescence technology serves to measure the spatial distribution of OH-radicals in a two dimensional cross-section area of the flame. Therefore the flame dimensions and location can be determined with high spatial resolution without influencing the flow or the reaction [ 4,5]."

Jan 1, 2012

By Ji-He Wei

Keywords: stainless steel, AOD refining, side and top combined blowing, mixing characteristics, water modeling The fluid mixing characteristics in the bath during the side and top combined blowing AOD (argon-oxygen decarburization) refining process of stainless steel have preliminarily been investigated on a water model unit of a 120 t AOD converter. The geometric similarity ratio between the model and its prototype (including the side tuyeres and the top lances) was 1:4. On the basis of the theoretical calculations for the parameters of the gas streams in the side tuyeres and the top lances, the gas blowing rates used for the model have more reasonably been determined. The influence of the tuyere number and position arrangement, and the gas flow rates for side and top blowing on the characteristics has been examined. The results demonstrated that the liquid in the bath underwent vigorous circulatory motion during gas blowing, without obvious dead zone in the bath, resulting in a well mixing effectiveness. The gas flow rate of the main tuyere had a governing role on the characteristics, a suitable increase in the gas flow rate of the subtuyere could improve mixing efficiency, and the gas jet from top lance could make the mixing time prolong. Corresponding to the oxygen top blowing rate specified by the technology, a roughly equivalent and good mixing effectiveness could be reached by using six side tuyeres with an angle of 27 degrees between each tuyere, and five side tuyeres with an angular separation of 22.5 or 27 degrees between each tuyere. The relationships of the mixing time with the gas blowing rates of main-tuyeres and sub-tuyeres and top lance, the angle between each tuyere, and the tuyere number have been obtained.

Jan 1, 2005

By M. J. Adam

The Bureau of Mines is investigating the feasibility of partitioning complex sulfide minerals to simpler sulfide phases by sulfidation reactions. Such partitioning can afford opportunity to improve selective extraction of mineral constituents of value. This report describes research involving sulfidation partitioning of byproduct chalcopyrite concentrates from Missouri lead ore processing, and a Utah chalcopyrite concentrate from Cu ore processing. Small chalcopyrite samples were sulfidized with elemental S in glass capsules sealed after evacuating and backfilling with He, by heating for 1 to 24 h at specific temperatures in the range of 250? to 500? C, extending from below to above the boiling point of S (-4450 C).

Jan 1, 1987

By John W. Ahlrichs

Microscope, electron microprobe and x-ray diffraction have been used to provide quantitative evaluation of products from the mill, smelter, refinery and other metallurgical processes. Phase compositions and their quantities are necessary for an adequate understanding of the various products obtained throughout an operation and in laboratory testing. By careful evaluation, important information can be gained in improving recoveries and increasing grades at various stages of processing. Four case histories are discussed in this paper. Quantitative microscopic counting techniques are applied to mill products to determine degrees of locking and liberation of the economic minerals. Rapid, but accurate evaluation aids the metallurgist to develop or improve the grinding and flotation circuits. In the smelter, the identification and quantification of the phases are important for predicting reaction mechanisms and kinetic trends. Mineralogic techniques have been applied to conventional smelter products, and to those obtained in laboratory tests for newly developed innovations to smelting. Small, but important, values of gold occurrences in ore are difficult to determine. Evaluation of gold usually requires special separations into various mineral concentrates, followed by assays and mineralogic determinations of the products. Numerous occurrences of solid solution constituents can be treated as by-products, but often they are deleterious to metallurgical treatment. Most solid solution problems can be unraveled by the mineralogist's tools.

Jan 1, 1981

By Ruiling DU, Jiazhi Zhang, Yong Zhao, Keng Wu

Reaction kinetics of metallurgical physical chemistry which was successfully applied in metallurgy (as ferrous metallurgy, non-ferrous metallurgy) became an important theoretical foundation for subject system of traditional metallurgy. Not only the research methods were very perfect, but also the independent structures and systems of it had been formed. One of the important tasks of metallurgical reaction engineering was the simulation of metallurgical process. And then, the mechanism of reaction process and the conversion time points of different control links should be obtained accurately. Therefore, the research methods and results of reaction kinetics in metallurgical physical chemistry were not very suitable for metallurgical reaction engineering. In order to provide the definite conditions of transmission, reaction kinetics parameters and the conversion time points of different control links for solving the transmission and reaction equations in metallurgical reaction engineering, a new method for researching kinetics mechanisms in metallurgical reaction engineering was proposed ,which was named stepwise attempt method. Then the comparison of results between the two methods and the further development of stepwise attempt method were discussed in this paper. As a new research method for reaction kinetics in metallurgical reaction engineering, stepwise attempt method could not only satisfy the development of metallurgical reaction engineering, but also provide necessary guarantees for establishing its independent subject system.

Jan 1, 2015

By Corby G. Anderson

Hydrometallurgical technology for the pretreatment of refractory gold concentrates has been developed at Sunshine Mining and Refining Company. It employs a patented nitrous-sulfuric acid pressure leaching process which' was proven industrially at the Sunshine refinery. Additionally, pretreatment for removal of antimony and some other impurities is done with alkaline sulfide leaching. This paper will discuss the successful application of these two technologies for pretreatment of a refractory gold concentrate prior to CIL gold recovery. A complex gold concentrate composed of pyrite, arsenopyrite and stibnite was tested. Results of antimony leaching in alkaline sulfide media will be discussed including some details of a novel and selective recovery method for gold leached by polysulfide or thiosulfate" Also, the factors important in and the results of the application of nitrogen species catalyzed pressure leaching to refractory gold concentrates will be detailed.

Jan 1, 1996

By Zhi-yong Liu

A novel process, which includes hydrochloric acid leaching, iron powder cementation, sulphide precipitation and spray pyrolysis, was proposed to treat iron concentrate recovered from zinc kiln slag for comprehensive utilization. Treated by two-stage hydrochloric acid leaching, the leaching extents of Ag, Pb, Cu, Fe and Zn are 96.78%, 95.14%, 97.72%, 94.51% and 87.74%, respectively. More than 99% Cu and Ag are recovered from the leach liquor when iron powder is 25% higher than the stoichiometric requirement. More than 96% Pb and Zn is removed with three times of theoretical consumption of FeS, and the concentration of impurities of the final solution is less than 500 mg/L. Fe2O3 powder, which is spherical with a mean size of 12 μm and purity of 99%, is prepared with final solution at 700 °C. In this process, not only the metal values can be recovered effectively, but also the iron resources of zinc kiln slag can be converted into high purity Fe2O3, thus, the comprehensive utilization of iron concentrate recovered from zinc kiln slag can be realized.

By M. R. Baren

Unpublished results obtained by Baren on thermodynamic properties of sulfur in liquid Fe. Co. Ni. Fe-Co. Fe-Ni. and Co-Ni are reevaluated. correlated. and interpreted on the basis of recent developments in thermodynamics of alloys:. Existing reliable data are reviewed and compared with the? present results. Sulfur obeys Henry's law up to 0.04 mol fraction. and in this range the standard Gibbs energy of solution of sulfur is expressed as a linear function of temperature for each pure metal. The activity coefficient of sulfur in each binary metal solvent 1s correlated with the composition of alloy.

Jan 1, 1983

By Rina Kim

The addition of lead to a gold leaching reactor can effectively accelerate or retard the gold cyanidation reaction. This study explored the effect of lead on the gold dissolution kinetics using cyclic voltammetry (CV) experiments. It was illustrated that the gold leaching kinetics in the cyanide solution enhanced with the addition of lead salt in the low overpotential region (–0.35 V vs. Ag/AgCl). The similar behavior was observed in the presence of ore containing 0.25% galena. In contrast, the gold oxidation kinetics retarded at –0.35 V (vs. Ag/AgCl) in the presence of silicate and lead-bearing mineral under certain conditions. Likewise, the lead addition was not functional for the high sulfur ore. This was attributed to the oxidation of the sulfides to the elemental sulfur, which subsequently formed a passivating layer on the gold surface. The results were evidently affirmed by the electrochemical tests and X-ray photoelectron spectroscopy (XPS) analysis.

By Eric Pirard

Theoretical studies carried out on shape analysis supply mathematical tools to analyze the influence of grain shapes on ore beneficiation. In the case of statistic images like those encountered in applied mineralogy parametrical and harmonical analysis methods are used. It is important that the shape parameters are adapted to the specific processes involved in ore beneficiation, while remaining easy to manipulate. The inertia parameters are considered in the scope of granulometric and gravimetric processes It appears that they are able to distinguish between the resulting products where very popular shape parameters are not. The measured statistics are analyzed through discriminant analysis procedures in order to estimate the importance of morphological differentiation and the aptitude of shape parameters to account for this.

Jan 1, 1989

By Jared Ball, Darren Snashall, Paul Telford, Pengfu Tan, Ben Hogg

"The foamed converter charges were up to 3 8 per month in Xstrata Copper Smelter at Mount Isa. The issue of high converter foamover frequency had remained unsolved for many decades in Mount Isa. A thermodynamic model of copper P-S converter and a viscosity model of converter slag have been developed to simulate the slag blow and copper blow, in order to understand the mechanism of converter foamover. The model predicts the chemistry and viscosity of slag during slag blow and copper blow. The effects of oxygen potential, charge of dirty reverts, slag carryover, under-blowing, over-blowing, and temperature on the foamover and viscosity of slag in copper blow have been discussed. A theory has been developed to understand the mechanism of converter foamover. The practical solutions have also been developed and implemented in Mount Isa Copper Smelter. Some improvements of the industrial operations have been presented. After a series of improvements, the number of foamed charges per month in the converter operations has been decreased significantly from 35 in Aug 2008 to only one per month in 2009/2010.1. IntroductionThe Copper Smelter in Mount Isa receives the concentrate containing about 25% copper and produces anode copper that contains about 99% copper. There are several stages in the process. The first stage carries out in the ISASMELT™ furnace. The ISASMELT™ process produces a molten copper matte containing about 60% copper. An iron-silica slag and a sulfur dioxidebearing off-gas are the by-products of the process. The slag is taken to the slag dams for cooling before it is recycled through the Mount Isa Copper Concentrator.The matte is sent to Peirce-Smith converters. The converters further remove iron and sulphur to produce blister copper which contains about 97% copper. The anode furnaces remove any remaining sulphur and oxygen to produce anode copper that is about 99. 7% pure. This is cast into anodes and sent to the Xstrata Copper Refinery in Townsville for final refining.In the copper pyrometallurgical industrials, slag foaming is an important phenomena which occurs when the gas bubbles have stability and not rupture. Foaming greatly increases the interfacial area between matte, slag and gas and is essential for the operation of high intensity smelting processes. However, foaming or foamover is undesirable in P-S converter since it can damage the equipment and injure the operators. Figure 1 shows that the whole process of a foamover development in a converter."

Jan 1, 2011

By Omid Marzoughi

Chromium has a wide range of applications, including as an alloy addition in various steels and also as a corrosion resistance coating. Carbothermal reduction of chromite ore (FeCr2O4) in a submerged arc furnace is an important industrial process for extracting chromium, but the energy consumption is excessive. It is suggested that one area for future research is the low temperature carbothermic solid state reduction of chromite to produce an intermediate product, which can subsequently be upgraded to ferrochromium. In this regard, a thermodynamic model has been developed to investigate this process and the effects of temperature, carbon additions and ore composition on the recovery of chromium and the grade of the ferrochromium, have been studied. Further development of the model may allow it to be applied to the simulation of other processes for the recovery of chromium from chromite ores.

By J. A. Eisele

There is currently much interest in how extraction of gold and silver from ores with acidic thiourea solution compares with extraction using alkaline cyanide solution. Agitation leaching tests were performed by the Bureau of Mines on 14 precious metal ores using sodium cyanide (?NaCN) and thiourea [(NH2)2CS) as extractants. The objective was to compare the results of the two extractants. NaCN was used at a concentration of 2 g/L with and without H202 as an oxidant. (NH2)2CS was used at concentrations of 2 and 20 gjL, and the solution potential was controlled at 390 to 420 mV standard hydrogen electrode (Eh) with Fe2(S04)3. With both reagents a.t 2 g/L extractant levels, NaCN extracted more gold and silver than (NH2liCS from all of the ores. At 20 g/L (NH2)2CS compared with 2 g/L NaCN, (NH2)2CS extracted more gold than NaCN from two ores, the same amount from one ore, and more silver from one ore. NaCN extracted more gold than (NH2 )2CS from 10 ores and more silver from 4 ores.

Jan 1, 1989

By N. L. Piret

Primary and secondary copper smelting dusts are being generated in varying quantities with very dissimilar characteristics due to the different compositions of feed materials and the type of process utilized. After categorizing the multitude of dust types, the criteria for on-site and off-site recycling of smelter dust in terms of type and concentrations of the accompanying elements are established. Thereby, consideration is given to the important aspects of: ? optimization of copper recovery ? quality of copper product ? valorization of accompanying elements ? elimination and disposal of deleterious impurities ? minimization of impact on operation ? effects on operating costs ? environmental impact of dust treatment on overall process Existing commercial, emerging and proposed copper smelting dusts, pyrometallurgical as well as hydrometallurgical, treatment schemes are reviewed and evaluated technically, economically and environmentally in an attempt to streamline the vast number of proposed options. Thereby, the high selectivity achievable in hydrometallurgical dust processing due to it being complementary to the smelting process is expected to be given increased consideration.

Jan 1, 1995

By H. H. Kellogg

The thermochemical properties of molten solutions in the binaries Cu-Bi, Cu-Sb and Bi-Sb, as well as the ternary Cu-Bi-Sb, have been correlated and described in mathematical form by use of the associated species concept combined with the three-suffix Margules equations to account for the non-idea 1 behavior of the solution species. Agreement of the correlations with experimental data is excellent (relative deviation of less than 2.5% in the values of the activity coefficients) in most cases. The correlations are applicable over the entire composition range of each system, and in the temperature range 700°-1250°C.

Jan 1, 1985

By Florian Kongoli

New operating conditions and process parameters are often necessary in today's industrial practice of non-ferrous smelting and converting in order to accommodate various new chemical compositions of mineral charges and environmental requirements or to conceive new and more efficient industrial technologies. An important parameter in non-ferrous smelting and converting is the liquidus surface of multicomponent slags. This surface is affected by multiple factors such as temperature, gaseous potentials, the content of each component in the slag, etc., and cannot be quantified by the existing ternary liquidus diagrams. In this work a new type of representation of the liquidus surface of multi component systems has been presented by means of a thermodynamic model. This representation waives the need of the multidimensional representation of multi component systems and yields practical two-dimensional diagrams, which can be easily used in the industrial practice.

Jan 1, 2000

By Nobumasa Kemori

Six kinds of copper '90ncentrates. were treated individually in a ,pilot scale. Outokumpu flsah smelting furnace ~n order to study their ?flash smelting behavior with respect to oxygen efficiency and dust generation. The copper concentrates tested were selected from the more than twenty sources which are treated at the Sumitomo Toyo copper smelter, so as to provide a wide range of chemical composition in terms .of Cu, S,Fe, Pb + Zn + As, and Si~ content. Oxygen efficiency 'and dust generation rates obtained in 'the experiments ranged from 80% ,to 108% and 11% to 20%, respectively. Relationships between these results and experhnental conditions such as chemical and mineral composition of the copper concentrates, flux ratio, fuel consumption and so on are also discussed quantitatively in this paper.

Jan 1, 1998

By Teixeira

An experimental investigation on the kinetics of oxidation of As(III) with H202 in synthetic effluent solutions followed by precipitation of Fe/As (V) compounds was carried out. The variables investigated were: As concentration (200 -3000 mg/l) , oxidation pH (2.0 -11.0), oxidation temperature (25 -800C) , H202 stoichiometric excess (50% -100%), precipitation pH (5.0 -7.0), precipitation agent (Fe2+ -Fe3+). Fixed conditions were, Fe/As molar ratio (6:1) and stirring speed (560 rpm). The results were empirically modelled. The precipitates obtained were amorphous. The precipitates were checked upon their environmental stability according to the United States Environmental Protection Agency (U.S.E.P.A.) Toxicity Test, and were considered to be adequate for deposition in impermeable waste dumps. The combined Fe/H202 detoxification process, in selected conditions, was able to reduce the As contents of effluents containing 1600 mg/l As to 0.1 mg/l, in about 2 1/2 hours of total processing time.

Jan 1, 1990