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Numerical simulation of the fluid flow and heat transfer has been carried out for a waste-heat boiler in an Outokumpu type copper flash smelter. In this boiler, SO2-containing off-gas flows into the waste-heat boiler radiation section at about 1350°C. A fraction of cooler off-gas from the electrostatic precipitator at about 200°C was recirculated into the radiation section, and a small amount of ambient air was leaked into the boiler from the bottom. The computational results show that the flow is strongly recirculating and distinctly three dimensional in most of the boiler, particularly in the radiation section. The hot off-gas cooled down rapidly after entering the radiation section due to radiation. The predicted flow pattern and temperature distribution were in a good agreement with laboratory models and industrial measurements.

Jan 1, 1995

By Ping Long, Peipei Liu, Xinlin Ren, Yunke Wang, Bin Yang, Jian Wu, Wenli Zhang

In this research, ICP-AES was used for determining ten impurity elements (Fe, Pb, Ca, Mg, Cu, Zn, Al, As, Sb, and Bi)in tin concentrate and smelting products, such as crude tin and slag. Samples were dissolved by hydrochloric acid and nitric acid. Determination conditions were investigated in detail. Influences of matrix and coexisting elements were eliminated by selecting proper analysis spectral lines. Under the optimum conditions, the correlation coefficient of cali- bration curves were higher than 0.999. The detection limits of these ten impurities were in the range between 0.0009 to 0.0621 lg/ml. Relative standard deviation (RSD) values were lower than 6.0%, and the recoveries of standard addition were between 85 and 109%. The proposed method was demonstrated to be reliable by comparingwithstandardanalysismethodsandcertifiedvaluesofstandardsample. It could be applied for determining impurity elements in tin concentrate and smelting products successfully.

Mar 1, 2017

By H. Y. Sohn, Y. Mohassab, D. -Q. Fan, M. Elzohiery, A. Abdelghany

The Flash Ironmaking Technology being developed at the University of Utah is aimed at producing iron directly from iron oxide concentrate. In this technology, the concentrate is reduced by H2 and CO gas mixtures formed from the partial oxidation of natural gas in a flash reactor. Natural gas represents an economically and environmentally superior reductant/fuel for the flash ironmaking. The rate equations for the reduction kinetics by H2, CO and H2 + CO gas mixtures were determined in the temperature range 1150–1600 °C. These rate equations were applied to experimental results from a laboratory flash reactor using Computational Fluid Dynamics CFD simulation. A new mini-pilot reactor, which is capable of operating at 1150–1550 °C with a concentrate feeding rate of 2–5 kg/h, has been installed. Commissioning of the reactor with an emphasis on preheating of the reactor, production of reducing gas mixtures and the feeding and collection of iron ore concentrate and product particles has been completed.

Mar 1, 2017

By H. Y. Sohn

The considerable progress made in the sulfide smelting technology since the first International Sulfide Symposium of 1983 is discussed. The new developments and innovations have largely been driven by the recognition of environmental concern as well as the need for increased productivity. The smelting technologies for various nonferrous metals are reviewed, with an emphasis on the industry trend towards larger plants and continuous processes. The tremendous advances made in process modeling and computer simulation to describe the complex smelting processes are also reviewed. The goal of these mathematical models is the quantitative description of the processes and the reactors that will provide a means for the control and optimization of smelting operations as well as the optimal design of the operating conditions and the reactors. Environmental issues remain a key consideration in the smelting industry. One of the most remarkable improvements made in the last fifteen years since the 1983 Sulfide Smelting Symposium is the rapid increase in the sulfur capture by nonferrous smelters. This and other related issues are briefly discussed. Finally, the challenges that the smelting industry faces as the new millenium approaches are discussed. The industry continues to face technical challenges to improve productivity and efficiency, while being responsive to ever-increasing public pressure for environmental protection. It also faces external challenges from factors that may cause the reduction of metal uses as a result of substitutions by other materials. Another serious challenge and dire consequence that the primary metals industry is expected to face is the serious diminution of university-educated manpower as well as basic-research output. To remain competitive and healthy, the industry should take up the void left by the complete disappearance, at least in the U.S., and the reduction in other nations, of the governmental support of higher education and basic research in the field of primary metals production.

Jan 1, 1998

By Evgenii Pavlov, Ivan Tronin, Viktor Timofeev, Vladimir Kislov, Sergei Bogovalov

"Modeling of the magnetohydrodynamical (MHD) and thermodynamical processes during the industrial scale Direct Chill (DC) casting of aluminum slabs is performed using a combination of ANSYS/CFX and ANSYS/EMAG software. The electromagnetic field is modeled through ANSYS/EMAG, while hydrodynamic and thermodynamic processes are modeled through ANSYS/CFX. Both packages were modified in order to calculate MHD flows in the liquid pool that forms during aluminum DC casting, and they were unified into a software combination that provides simultaneous simulation of all the above processes. The simulation shows that the electromagnetic stirring of the molten aluminum changes the shape of the solidification front (solid-liquid interface) very dramatically, namely it becomes significantly flatter. This effect should improve the internal structure of aluminum DC slabs and allows us to increase the casting velocity.IntroductionProduction of Aluminum alloys with high mechanical properties and structural uniformity is one of the main goals of industry. The preferred production method of aluminum alloys in most modern plants is Direct Chill (hereafter DC) casting because it offers high productivity and commercial success. One important limitation of this technology is the development of centerline shrinkage in slabs larger than about 1 meter. The improvement of the internal structure of long DC cast slabs can be achieved by electromagnetic stirring (hereafter ES) of the liquid metal above the solidification front. This intensifies heat transport in the zone close to the solidification front and suppresses shrinkage formation."

Jan 1, 2013

By Marietta Canty

A paper is presented in which an innovative biological process is described for the treatment of cyanide-, metals-, and nitrate-contaminated mine process water. The technology was tested for its ability to detoxify cyanide and nitrate and immobilize metals in wastewater from agitation cyanide leaching. A pilot-scale demonstration is described in which a pilot plant was constructed to demonstrate the technology on a mine process waste stream at a mine in Nevada. The demonstration was performed Jointly under the Mine Waste Technology Program (MWTP), which is funded by the U.S. Environmental Protection Agency (EPA) and is jointly administered by the U.S. Department of Energy's (DOE) Western Environmental Technology Office (WETO) and the Superfund Innovative Technology Evaluation (SITE) Demonstration Program under Interagency Agreement Number DW89938513-0 I-0. MSE Technology Applications, Inc. (MSE) located in Butte. Montana, was the contractor responsible for conducting the project, and Pintail Systems, Inc., of Aurora. Colorado, was the technology provider. The pilot-scale unit was field-tested at the Echo Bay McCoy/Cove Mine southwest of Battle Mountain, Nevada. The biotreatment process was considered to be successful in destroying cyanide in the mine process water. The process was also determined to be effective in removing metals. The pH was consistently neutralized, and nitrates were successfully removed from the mine process water. As a result of conducting these pilot-scale tests, the biotreatment process was concluded to be an innovative, cost-effective alternative for the treatment of mining wastewaters.

Jan 1, 1998

By Larry Southwick

This Peirce-Smith Converting Centennial symposium is celebrating the contributions of two men, William Peirce and E.A.C. Smith, in advancing technology allowing the copper industry to realize its full potential. However, theirs is representative of a larger story: New, simpler technology releasing the stranglehold of older, more complicated technology, new developments in vessel configuration and design finding alternate routes around dead ends in operability, advances in technique and concepts removing roadblocks of cycle time and capacity, and overall innovation opening up vast new reserves around the world to those companies willing to embrace those improvements. Our story is also one of personalities, stubborn smeltermen versus the innovators, those inside the industry versus those from outside. It is a story of an initial borrowing from the steel industry, but also Peirce and Smith, from the refining end of the copper business, taking the ideas of Baggaley from Pittsburgh’s steel and airbrake industry, who built on what Hollway, Manhès and David, Douglas, and others had done in smelter tests, further to compete with the previous primacy and closely held expertise of the copper smeltermen in Wales. These advances have been well recorded in photographs taken over the last 150 years. A number were submitted especially for this symposium. Many others were published in the mining and metallurgy press of the times. Several mining schools also retained copies of photos either taken during field trips, or donated to the school by alumni and operating companies. This presentation will provide a selection and discussion from these sources of “converters in action”, describing the various designs, operations and developments depicted. The focus here will be on the first roughly 60 years of copper converter development, from Bessemer’s days at the dawn of this new idea, up to and slightly past the time of initial adoption of Peirce and Smith’s designs.

Jan 1, 2009

By K. S. Izbakhanov

The Chimkent Lead Plant was constructed in 1934 and since that time has undergone many revisions. In 1975 the slag fuming operation was changed from pulverized coal to natural gas fuel. In 1981 the slag fuming furnace water jacket system was converted to evaporative cooling with high pressure steam production. The impact of these changes and the method of their application are described.

Jan 1, 1990

By E. vanHuyssteen

A method of establishing the relationship between the mineralogy of a sinter and its subsequent processing behaviour in a lead blast furnace is demonstrated. It involves: 1) analyzing the Zn-spinels, hardystonite, larsenite, Pb-silicates, Pb-arsenates, Pb-(Ca)-sulphates and other femtes with an electron microprobe; 2) determining the extent of elemental substitutions in various mineral structures; 3) establishing a sequence in which the various phases formed during sintering. In this manner the relationship between the bulk chemistry of a sinter formulation and the speciation of elements into various phases in the sinter can be established. Specifically, the-substitution of Mg for Zn in hardystonite significantly influences sinter production. Mg substitution releases Zn into the surrounding matrix. This Zn reacts with the Pb-silicate to form larsenite thereby reducing the amount of Pb-silicate available for anhydrite digestion. Excessive amounts of residual anhydrite thus result if the sinter formulation is based solely on the CaO/Si& ratio.

Jan 1, 1993

By M. A. Kader, M. A. Islam, P. J. Hazell, M. Saadatfar, J. P. Escobedo, A. D. Brown

The dynamic pore collapse mechanisms and energy absorption capacity of closed-cell aluminium foams subjected to low velocity impacts have been investigated. Impact experiments were carried out using an instrumented drop-tower with two impactor geometries: a 50 mm square flat steel impactor to investigate pore collapse mechanisms and a 20 mm diameter hemispherical steel impactortostudy indentation resistance.X-ray computedtomography was utilized to generate views of the deformation field within the impacted specimen. The results show that the strain rate and incident impact energy influence the energy absorption capacities of closed-cell aluminium foams. Furthermore, damage initiation, propagation and cell collapse mechanisms under drop weight impact have been elucidated.

Mar 1, 2017

By Sevket Acar, Tim Acton

"Zarafshan/Newmont is a 50/25/25 joint venture between Newmont Gold and the State Committee for Geology and Mineral Resources, and Navoi Mining and Metallurgical Combinat, two entities of the Republic of Uzbekistan. The Zarafshan/Newmont joint venture consists of a heap leaching operation which will process 220 million metric tonnes of existing low-grade oxide ore stockpiles (averaging 0.036 oz Au/t) from the Muruntau mine. Net recovery over the 17-year life of the project is expected to be 4.8 million ounces of gold.The plant construction started in October 1993 and operations commenced on May 25, 1995. The crushing plant consists of four stages of crushing and screening to produce a 95% passing 3.35 mm product, followed by heap leaching and gold recovery by the Merrill-Crowe process. The dore metal is refined at the Muruntau refinery. All gold produced by the joint venture is sold on the world market. IntroductionThe Muruntau mine and nearby town of Zarafshan are located in the center of the Kyzylkum desert, 250 miles west of Tashkent, capital of Uzbekistan. Following a mining conference in Moscow in 1990, a Newmont geologist was among the first team of westerners to visit the Muruntau Mine, the second largest gold producer in the former Soviet Union. At Muruntau, they found 220 million tonnes of low grade gold ore that had been stockpiled during the previous 25 years. In February, 1992, six months after Uzbekistan's independence, Newmont signed a 50/50 joint venture agreement with the Uzbek government to use heap leach technology to process the ore. The feasibility study was completed in November of 1992. Plant construction started in October, 1993 and operations commenced on May 25, 1995.Newmont Metallurgical Services performed metallurgical studies to obtain heap leach process design criteria parameters. The initial metallurgical study on 20 grab samples is the subject of this paper."

Jan 1, 1997

By Joseph Hamuyuni, Fiseha Tesfaye, Daniel Lindberg

E-waste management through traditional methods such as disposing in landfills, burning in incinerators or exporting abroad for disposal are no longer options due to the strict environmental regulations. Fortunately, the presence of valuable metals in the e-waste and increasing demand for the metals as well as complexities of the currently available primary raw materials make recycling an attractive and viable option both environmentally and economically. Moreover, it is efficient in terms of resource management by closing the loop of metals. Consequently, urban mining such as the recovery of precious metals from e-waste streams through sustainable recycling processes have emerged. The sustainable recycling practices address the scarcity of primary resources and reduce consumption of energy for metals production while managing environmental issues related to hazardous materials from the e-waste streams. In this paper, valuable metals recoveries from e-waste streams through pyrometallurgical and hydrometallurgical processes are critically reviewed. And, innovative ideas for different steps of the thermochemical processes in the valuable metals and energy recovery from the e-waste streams are discussed.

Mar 1, 2017

By L. R. Verney

About 75% of the market economy countries's supply of cobalt is produced in Central Africa by Zafre and Zambia. Zafre alone accounts for more than 55% and has the resources and capacity to increase output significantly at any time so its dominant position is unlikely to be challenged in the foreseeable future. Other producers from domestic resources are Canada, Australia and South Africa; and Cuba, probably the most important producer outside of the Market Economy countries. Belgium, Norway, France, Japan and Finland produce cobalt from imported materials. While there are "cobalt ores", inMorocco, USA, Canada and the USSR, the mineralisation is complex and cobalt extraction is costly. In ZaPre and Zambia cobalt is a by-product of copper; in Canada, Australia, France, and Cuba it is a by-product of nickel; and in South Africa it is a by-product from the production of Platinum Group Metals. Thus the levels of cobalt production are inevitably related to the production of other primary metals. While some cobalt is produced by predominantly pyrometallurgical methods most of the world's cobalt is produced hydrometallurgically. The existence of large hydro-electric power plants and the mineralogy of the copper and cobalt concentrates encouraged research and development in Zafre of the recovery of copper and cobalt by electrowinning from sulfate solutions; much pioneering work was carried out, which lead to construction of the two largest copperlcobalt hydrometallurgical plants in the world, at Shituru and Luilu. Similar systems were adopted in Zambia. In Canada high pressure hydrometallurgical processes based on the sulfate system were developed and adopted in Australia, the Philippines, Finland and South Africa. Meanwhile developments in chloride hydrometallurgical extraction of nickel and cobalt lead to its use in the extraction of cobalt in Norway, France and Japan.

Jan 1, 1988

By David G. Dixon

Although the kinetics of leaching processes are of paramount importance in the design and analysis of nearly all hydrometallurgical flowsheets, these concepts remain poorly understood and, as a result, are only rarely applied to mass and heat balance models. In this second of two papers, we demonstrate how simple yet powerful models of leaching kinetics and other rate processes may be added to mass and heat balance models, and apply these concepts using a spreadsheet model of a simplified pyrite autoclaving flowsheet. In particular, we focus on the interpretation and scale-up of batch leaching data, and on simple means for modeling other phenomena commonly associated with leaching, such as reagent depletion, gas-liquid mixing, and the precipitation of oxides and basic salts.

Jan 1, 2002

By N. Kanari

The thermal decomposition studies of two zinc basic carbonate samples were carried out up to 400 "C by thermogravimetric analysis, boat experiments and differential scanning calorimetry measurements 'DSC'. The initial samples and the solid decomposition products were analyzed by scanning electron microscopy, x-ray diffraction and laser particle size analyzer. The thermal decomposition of both samples started at about 150 "C and the rate of decomposition became significant at temperatures higher than 200 "C. The apparent activation energies 'Ea' in the temperature range 150-240 "C for sample decomposition were between 132 and 153 kJ1mole depending on the sample origin. The XRD analyses of the intermediately decomposed samples and the DSC results up to 400 "C suggest that the decomposition reaction probably occur in a single step.

Jan 1, 2002

By T. K. Mukherjee, C. K. Gupta

"The importance of the processing of secondary resources such as solid industrial wastes and liquid effluents as well as byroducts for the recovery of the associated metal values hardly needs any elaboration. Such processing contributes in no small measure towards the augmentation of the availability and the supply position of resources. As an added benefit, it leads to a reduction in environmental pollution caused by the undesirable waste materials. As some typical examples of secondary resources in the Indian scenario, mention can be made of spent catalysts, metal/alloy scrap, ash, consumed batteries, flue dust, slag, sludge and slime, pickling solutions, spent acids, plating rinse solutions, spent etchants, waste water from synthetic fibre manufacture and from tanneries etc .. These wastes constitute a source of a variety of non ferrous metals. In the processing of secondary resources like these, the techniques of hydrometallurgy such as solvent extraction playa pivotal role.This paper outlines the efforts made to use solvent extraction to recover (1) base metals such as copper, zinc, nickel and cobalt from a number of secondary resources like cake, and sludge (2) refractory metals like molybdenum and vanadium from sulphidic byproducts and spent catalyst and (3) nuclear metal like uranium from phosphoric acid. In the case of base metals, process flowsheet involving the use of acidic extractants such as DEHPA and PC88A have been optimised. The problem of iron removal from the leach liquor, which influences the metal recovery process significantly, has drawn a special emphasis. In the case of refractory metals, basic extractants like Alarnine 336 has been pressed into service to produce kilogramme quantities of pure salts of molybdenum and vanadium. Finally, the paper gives a brief account of plant experience in recovering uranium from phosphoric acid, using a solvent system comosed of DEHPA and TOPO."

Jan 1, 1996

By J. A. S. Tenorio, K. S. Barros, D. C. R. Espinosa

In the last decades, authors have been focused in the development of a cyanide-free bath for the electroplating industry of brass due to the risks that involves the use of cyanide and they have been evaluated the electrodialysis as an alternativemethodforthetreatmentoftheeffluentgeneratedinthistypeofindustry because ofthe limitationscaused bythe chemical precipitation. Hence, thepresent paperaimedtodeterminethelimitingcurrentdensityoftheeffluentgeneratedinthe free-cyanide electrodeposition of copper and zinc using EDTA as chelating agent for the treatment of the effluent by electrodialysis. The synthesized solutions were preparedwith copper sulfate andzinc sulfate indifferent conditionsofpH (10–12) and proportion of cupric ions (30%, 50%, 70%). According to the results, the increase of pH and the cupric ions proportion caused an increase in the limiting current density because of the larger amount of anionic species in solution and the consequent difficult to achieve the concentration polarization phenomenon. (cid:1) (cid:1) (cid:1)

Mar 1, 2018

By Sunil G. Warrier

A rapid infrared forming technique has been developed to fabricate titanium matrix composites. This technique applies infrared heating to infiltrate titanium alloys into carbon and silicon carbide prepregs. The entire process typically takes 1-2 minutes in an inert atmosphere. The advantages of this technique are that the process is fast, simple, does not require a vacuum or a high external pressure. The process is very economical both in energy conservation and operation costs. This technique has been used to produce void free composites with limited, well controlled fiber-matrix reactions and mechanical properties comparable to currently available titanium matrix composites.

Jan 1, 1993

By Huaqing Xie, Qingbo Yu, Qin Qin

A novel sorption-enhanced steam reforming (SESR) process of hot coke oven gas (HCOG) was proposed for tar removal and H2 amplification, and was studied with the comparison of conventional steam reforming (SCR) process. Both of the processes could remove tar effectively and improve the H2 amount in the COG obviously. For CSR process, after the temperature and the S/HCOG ratio reached 700 °C and 2.4 respectively, the H2 amplification factor kept 4.30 around, with its concentration less than 75%. However, for SESR process, the H2 amount and concentration get improved further, with the optimal temperature moving toward low temperature. At 600 °C and the S/HCOG ratio of 2.4, the H2 amplification factor and concentration could reach 4.91 and 97.55% respectively when the CaO/C ratio was 2.0. Under the respective optimal reforming conditions of the two processes, the energy consumption of the SESR process was lower than that of CSR process.

Mar 1, 2018

By Autumn Fjeld

The filling and solidification of an industrial scale composite casting has been simulated to investigate the re-melting of the outer shell material during casting. Production of a composite requires a two-step casting process which includes centrifugal casting of a hard outer shell material and subsequent conventional ingot casting of a tough core material into the shell-mold assembly. During casting of the core, a thin layer of the shell material re-melts and mixes with the core material producing a bonding layer of intermediate composition. The present numerical model employs the volume of fluid method and an enthalpy-porosity technique to couple the filling of the core material and re-melting of the shell material. The interface between the two materials is tracked and can be used as a guide to examine the extent of melting and, to some degree, mixing of the two fluids and species diffusion.

Jan 1, 2008