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By Moenster J. A., M. J. Sankovitch

Doe Run's Buick Smelter was converted from a primary lead smelter to a secondary lead smelter in 1991. The recycling facility was designed to produce 60,000 tons of refined lead per year from 110,000 tons of spent starting-lighting-ignition (SLI) batteries and 10,000 tons of lead contained in drosses and scrap. Since commissioning, Buick's refined lead output has steadily increased to exceed 120,000 tons for 1999. The production gains have been the result of continuous process improvements, empowerment of the workforee, and development of additional scrap lead streams. The production gains were accomplished while setting industry standards for employee safety, reducing plant environmental emissions and employee blood leads, achieving ISO 9002 certification, and expanding product lines to meet customer requirements. This paper highlights Buick's major accomplishments through the 1990's.

Jan 1, 2000

By Ramana G. Reddy, Yuxiang Peng

The long-term corrosion behavior of Haynes 230 (H230) alloy in MgCl2–KCl eutectic salt was evaluated at 1273 K for 500 h in Ni crucible in argon gas. The results showed H230 alloy has good corrosion resistance. In addition, corrosion was noted to occur by depletion of Cr, which was deposited on the Ni crucible. Based on the calculation of Gibbs energy of Ni-Cr alloy and exchange current density of Cr in MgCl2–KCl, the Tafel model was constructed to investigate the corrosion potential and rate. The galvanic corrosion can be explained as the predicted results were in agreement with the experimental data.

Mar 1, 2017

By M. I. Novgorodova

Most of the gold in the earth's crust occurs as finely-dispersed gold and accounts for much of the gold lost in extraction processes and during exploration for gold. The Compositions, sizes, and morphology of fine gold particles (0.01 to 10 ~m in diameter) were studied with high resolution electron microscopy coupled with electron microprobe and microdiffraction devices, using colloidal carbon replicas. Correlations were made between fine gold, mineral associations and ore genesis. The results provide qualitative information on the proportions of finely dispersed, invisible and visible gold distribution in ores. Such knowledge is fundamental when planning an optimum technological recovery process.

Jan 1, 1991

By Asmo Vartiainen

Background of Direct-to-Blister Flash Smelting is discussed; especially slag chemistry relating to copper solubility, slag fluidity and impurity behavior. In December, 2000, Mini-pilot Flash Smelting test runs were carried out at Outokumpu Research Oy to produce blister copper from Chilean concentrate and white metal and from a mixture of them. Tested slag types were iron silicate slag, ferrous calcium silicate slag and calcium ferrite slag with different slag compositions and different concentrate/white metal ratios. The test runs were successful. The fluxing effect of copper oxide was clearly demonstrated and ferrous calcium silicate slags remained fluid on a very wide liquidus range. The distribution of arsenic between ferrous calcium silicate slag and blister copper is much higher than between iron silicate slag and blister copper. This successful test run with the new slag type offer new possibilities in Direct-to-Blister process design.

Jan 1, 2003

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from theUniversity of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

This symposium is dedicated to the lifetime achievements of Professor H.Y. Sohn. It covers the scientific fields, processing routes and investigation techniques in which Prof. Sohn has worked during his career and is based in the equally important three topical areas: Principles, Technologies, and Industrial practice. Professor Sohn was General Chair of the very first TMS Fall Extraction and Processing Symposium in 1983 in San Francisco which led to the Annual such symposia as this International symposium. Furthermore, the theme of that symposium was sulfide smelting, which is also included in this symposium. [ ] Professor Sohn was born in a beautiful dynastic capital Kaesung, Korea on August 21, 1941. He received his B.S. degree in 1962 from Seoul National University, M.Sc. in 1966 from the University of New Brunswick, Fredericton, N.B., Canada, and his Ph.D. degree in 1970 from the University of California at Berkeley all in Chemical Engineering. After working as a Research Associate at the State University of New York at Buffalo and as a Research Engineer at Du Pont?s Engineering Technology Laboratory, Dr. Sohn joined the Department of Metallurgical Engineering at the University of Utah in 1974 and currently holds the ranks of Professor of Metallurgical Engineering and Adjunct Professor of Chemical Engineering.

Jan 1, 2006

By H. D. Freeman

The occurrence of gold in refractory gold ores varies widely and affects the recovery process. The determination of gold and the composition of the associated minerals are important in selecting an appropriate processing scheme. However, locating the gold in an ore sample is a difficult task which requires perseverance, luck, and experience. Our experience has led to the development of a relatively fast and reliable means of deter-mining the mineralogy of ore samples through analysis combining an energy-dispersive x-ray analyser coupled to a scanning electron microscope (SEM). In some cases, a wave length dispersive spectrometer or microprobe is used to further quantify the various mineral compositions. The SEM/microprobe analysis identifies the source of problems that may arise during the recovery of gold from refractory gold ores.

Jan 1, 1981

By Gabriel Riveros

Fire refining of copper consists of two stages copper oxidation and copper reduction. Very frequently the capacity of the anode furnace is determined by the rate of copper reduction. The analysis of factors affecting the rate of the oxygen reduction from a liquid copper with solid carbon or injected hydrocarbons pointed out the role of the mass transfer in a liquid copper in final stage of the reduction. Experimental results of copper reduction with graphite and injected natural gas in laboratory- scale crucibles showed two stages of the reduction process with a sharp change of the controlling mechanism. The estimated dynamic surface area of gas bubbles based on the measured bubble frequency and the gas flowrate allowed for the detennination of the reaction constant as a degree of the partial pre-combustion of the air/natural gas mix. The variation of the used reductant as a function of the oxygen concentration and temperature has been evaluated based on the detennined kinetic model. The intensification of copper reduction in fire refining has been discusses on the basis of obtained kinetic data and analysis of various factors detennining the time of reduction.

Jan 1, 2003

By Debbie Marshall

Process water is an important consideration in the development of a nickel laterite project. Depending on the location of the ore body, sufficient fresh water may not be available and it may be necessary to use seawater (or saline groundwater) for ore preparation. This introduces various species, which have major effects on materials of construction and leaching chemistry. This paper summarizes batch testwork completed at the Falconbridge Technology Center. The leaching behaviour of eleven different laterite ore samples were compared using seawater and fresh water. For brevity, six of the eleven samples are reported here-the other five samples showed similar results. Each ore type was leached under identical conditions in both freshwater and seawater and the leaching chemistry compared. The batch test results were confirmed in a continuous pilot plant, and leach kinetics for the two systems were compared. Keywords: high pressure acid leaching, laterites

Jan 1, 2004

By T. Kamata, S. Takemoto, H. Takeuchi, M. Takayanagi, Y. Akahori, I. Jimbo

"A cooperative research work on the silver recycling process is underway between Matsuda Sangyo Co., Ltd. and Tokai University in Japan. Silver wastes treated here are mainly from photograph industries where the concentration of minor element is steadily increasing in the recent years. The waste materials are concentrated and the impurities are removed by evaporation and slagging. In this paper, the industrial practice of wastes treatment is introduced and the result of the laboratory studies on the removal of antimony and tin from the binary and ternary alloys will be discussed. Characteristics in the behavior of antimony and tin during the process are also discussed with the observation of practical operation.1. IntroductionPrecious metals such as gold and silver primarily come from mining practice and the byproduct in copper smelting. However, the recycled amount of these precious metals have been increased 1 along with the environmental restriction and the widely accepted idea of saving resources on the earth in the recent years.· Though the recycle process of precious metals are comparatively simple from other metals refining, the process has been getting more complicated as wastes treatment has to deal with more impurity elements which are intentionally added to the products. Among these additives, antimony is used in the film materials in the photography industries to suppress its inflammability. Tin is another concern ,that is also coming from photography wastes; These minor elements have become problematic during the recycle.The removal of these minor elements has been in operation at Matsuda through a traditional oxidation refinement process using a reverberatory furnace. However, the complexity of the charge makes the recycle process more tedious and troublesome. In order to investigate the minor element behavior in the complicated materials system during the silver recycling processes, a cooperative research work is undertaken between Matsuda Sangyo Co., Ltd. and Takai University in Japan. Silver wastes treated here are mainly discharged from photograph industries where the minor element contents such as antimony, tin and bismuth in those wastes are steadily increasing in the recent years. The liquid wastes containing silver are concentrated and then treated pyrometallurgically with solid wastes from other sources, where the impurities are removed ·by evaporation and slagging. The purpose of this study is to investigate detailed behavior of impurity elements in the silver. containing systems."

Jan 1, 2000

By Stavros A. Argyropoulos

Exothermic mass transfer takes place in various areas involving metallic systems, ranging from liquid metal processing operations to the growth of thin films in microelectronics. The formation of intermetallic compounds plays an important role in the exothermic mass transfer of metallic systems. Two types of exothermicity are identified , namely , Microexothermicity and Macroexothermicity. The former is encountered when small amounts of metals are mixed, while the latter is exhibited when a solid metal in a lump form is added into liquid metal. In this paper two types of exothermic mass transfer in metallic systems will be presented and reviewed. Mathematical modelling work for these types of exothermic mass transfer will be analyzed.

Jan 1, 1993

By John A. Vallomy

"The CONSTEEL Process introduces a new concept in electric steelmaking by continuously feeding-preheating-melting and refining ferrous scrap or direct reduced iron. The process uses the furnace off-gas and fuel to preheat the scrap in a specially designed preheater. Thermal incineration of the flue gas reduces the carbon monoxide level to the more stringent requirements. Hot water or steam production from heat of flue gas is optional. The tap-to-tap time is set to match the cycle of the caster. The steel is treated via ladle metallurgy. The environment inside and outside of the steelplant is improved by decreasing levels of noise and hazardous emissions. Energy consumption decreases and disturbance to the electric network is eliminated. A CONSTEEL prototype was tested at Nucor Steel, Darlington, SC. A greenfield project is in the completion stage at the Florida Steel plant of Charlotte, NC, USA. The Process PhilosophyThe philosophy of the CONSTEEL Process is not solely to enhance efficiency; this was just a natural result of the change from a batch to a continuous practice. The primary objective in development was four-fold:1) 100% process control2) Rational use of available energy3) Improved environment inside and outside the plant4) Stability of energy input from the power systemIt was to make electric steelmaking more a science than an art and amenable to modern automation.The Basic Concept of CONSTEELThe concept of the process is shown in figure and includes basically a continuous feeding system, a preheater and a melting - refining furnace. A pre-established amount of heat is introduced into the scrap while traveling through the preheater using the sensible and chemical heat contained in the furnace off-gas and additional fuel. Melting-refining is carried out in the electric furnace. Slag formers, slag foaming additions and oxygen are injected to refine the melted steel continuously, to minimize the refractory erosion, to shield the arc, thus optimizing the transfer to the metal bath of the heat generated in the arc, to keep the bath homogeneous in composition and temperature and to produce carbon monoxide (CO) which is fuel for the preheater."

Jan 1, 1988

By I. H. Gundiler

Sandia National Laboratories (SNL) is tasked to support The Department of Energy in the dismantlement and disposal of SNL designed weapon components. These components are sealed in a potting compound, and contain heavy metals, explosive, radioactive, and toxic materials. SNL developed a process to identify and remove the hazardous sub-components utilizing real-time radiography and abrasive water-jet cutting. The components were then crushed, granulated, screened, and separated into an aluminum and a precious-and-base-metals fraction using air-tables. Plastics were further cleaned for disposal as non-hazardous waste. New Mexico Bureau of Mines & Mineral Resources assisted SNL in investigation of size- reduction and separation technologies.

Jan 1, 1995

By Yuzura Sato

Viscosity has been measured for various molten binary alloys of nickel with iron, cobalt and chromium in order to clarify the behavior of viscous flow of molten nickel alloys. The entire concentration range for iron and cobalt and 0-67at% of chromium content were studied. The measurement method was an oscillating cup viscometry using an alumina crucible that was precisely machined. The temperature was up to about I 880K for all the measurements. The results represented good Arrhenian relationship although some measurements included overcooled temperatures. The isothermal viscosities increased monotonously with an addition of iron and chromium into nickel. The addition of cobalt increased after stationariness. The isothermal viscosities showed concave curves. Activation energies increased monotonously by adding all the elements into nickel. These phenomena were considered to be related to the thermodynamic properties 'such as the heat of mixing and the structures of mixture melts.

Jan 1, 2003

By Fabiano A. C. M. Passos, Vanessa P. R. Silva, Lillian M. B. Domingos, Fernanda A. N. G. Silva, Zuleica C. Castilhos, Roberto B. Faria

Wastes from gold mining need to be monitored from the beginning of mining activities until to the mine closure. Wastes from tailings dam were characterized by XRD, XRF, elemental analysis of carbon and sulfur and ICP-OES. In flotation waste (FW) were observed quartz, dolomite, pyrite, muscovite and chamosite were observed. Meanwhile, in cyanidation waste (CW), besides those described in FW, minerals such as sphalerite, galena, pyrrhotite, microcline and albite were detected, indicating a higher concentration of sulfide minerals in the cyanidation waste. In relation to C and S content, to FW and CW, they were 2.5 and 0.0% and 0.64 and 15.4%, respectively, confirming the majority of sulfides at CW sample and indicating the absence of the flotation organic reagents at the cyanidation waste. The analysis by ICP-OES indicated As, Zn, Pb, Cr and Cd content for FW and CW: 13.30 and 343 mg/kg; 399 and 7,900 mg/kg; 136 and 13,000 mg/kg; 130 and 260 mg/kg; 3.60 and 84.60 mg/kg, respectively. It was also verified significant levels of heavy metals, which indicates the necessity of performing wastes toxicity tests.

Mar 1, 2017

By Huaming Yang

The vanadium-doped SnO2 nanoparticle was synthesized by the co-precipitation reaction and subsequent calcination from the vanadium(III) chloride and tin(IV) chloride. The crystal size, pore size distribution, micrograph and properties of the nanocrystalline powders were examined by differential thermal analysis (DTA), thermogravimetric analysis (TGA), X-ray diffraction (XRD), desorption isotherm (Barrett-Joyner-Halenda method) and transmission electron microscopy(TEM). Thermal treatment of the precipitate powder at 600°C led to the formation of V -SnO2 nanoparticle of -10mm in crystal size. Most of the pores in the nanoparticle are about 5~15nm in diameter. Effect of doped vanadium on the crystal size of the nanopartic1e was discussed.

Jan 1, 2003

By James B. Pfeiffer

TETRA Technologies, Inc., has applied its HDSIM metals precipitation system to treat a waste stream containing scrubber blowdown and process water from a smelter operation. The combined stream contained cadmium, lead, selenium, arsenic and zinc, plus some iron and copper. Treatment requirements included meeting stringent mass flow limitations for specific heavy metals. The HDS ? system can reduce the arsenic from 600 ppm to less than one ppm. The process generates a dense sludge that can be reprocessed in a smelter, eliminating the liability associated with landfilling. Flow diagrams and process details are discussed.

Jan 1, 1994

By Jian Ye

Recycling of aluminum scrap, such as Used Beverage Container (UBC) scrap is steadily increasing. In secondary remelting of such scrap, it is a common practice to use protective molten salt cover. An appropriate salt protects metal from oxidation, promotes coalescence of the suspended metal droplets, and separates clean metal from the oxide contamination. The molten salt also reacts with metal. This causes metal loss and change of resulting metal composition. In this paper, role of molten salt fluxes in melting of UBC scrap is discussed, and selection criteria for molten salt are provided.

Jan 1, 1995

By Beatryz C. Mendes, Henrique de Paula Santos, Kléos M. L. Cesar, Eduardo Antônio G. Marques, Maurício Paulo F. Fontes, Rita de Cássia S. S. Alvarenga

Inadequate discard of industrial solid waste is a risk to human health and to the environment. Aiming at softening environmental damage caused by deposition on soil of an ink residue, from washing of printers used in carton box packages, it is intended to incorporate this residue into soil-cement bricks. The residue has other use potentialities such as in screeds, pavement parts, fertilizer, paints, etc. However, to explore these potentialities it is fundamental to assess the risks that the several forms of use of this residue can cause. For such, in this work the chemical analysis of the residue was performed in order to know its main chemical compounds, in addition to its characteristics of leaching and solubilization. The chemical composition assay showed traces of some heavy metals such as Pb, Cd, Cr, Zn, Al and Cu, although the residue-generating company uses ink labeled as heavy metals free. Among the elements analyzed in leaching and solubilization, some had concentration above the limit allowed by The Brazilian Codes. This code is based on CFR—Title 40—Protection of Environment—Part 260–265—Harzardous waste management. Therefore, it is suggested that the residue has a limited use to avoid contamination of ground water.

Mar 1, 2017

By Jiang Fan, Liu Shi, Wang Haigang

Winter-time natural convection in gravel embankments has been suggested as a technique to provide passive cooling and thereby avoid thaw-settlement of roadways located in permafrost areas. Numerical simulation by finite volume method on the proposed model is perf9rmed using the software FLUENT. A gravels model, in which the embankment is composed of stones and air, has been adopted to investigate the temperature and velocity fields in embankment. Simulation results show that in summer, a weak clockwise circulation of the pore air extending throughout most of the embankment. The pore-air motion is very weak which results in relatively straight horizontal isotherm lines. And heat transfer is mainly maintained through conduction. But in winter, pore-air velocities are higher and multiple vortexes are formed in the embankment. Natural convection then becomes the dominant influence on the isotherm shapes within the embankment. As a result of low ambient temperatures exerted on the embankment surface during winter months, an unstable air density gradient develops within the embankment. This convection increases the heat flux out of the embankment. Therefore, the winter-time convection can further reduce the temperature of the foundation soil beneath the open-graded embankment. In addition, the effects of the size of the stones within the embankment have been analyzed and compared in the gravel model. It shows that in winter, 200mm stones lead to stronger vortexes in the embankment compared with those of 60mm stones. Consequently, the zone oflow-temperature beneath the embankment is extended.

Jan 1, 2004