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By Evan O. Jones

Processes involving distillation under reduced pressure were developed at the Pacific Northwest Laboratory several years ago to recover spent acid solutions generated during the manufacture of nuclear fuel for the N-Reactor at the Hanford site. Following construction and testing of a pilot-plant, the technology was licensed to Viatec Recovery Systems, Inc. for commercialization. The technology developed included specialized distillation and rectification of volatile acids, removal of water and/or volatile acid from sulfuric acid, and precipitation of salts. A key feature of the Waste Acid Detoxification and Reclamation (WADR) technology is the development and use of advanced thermoplastic and fluoropolymer materials of construction in all critical process equipment. The technology was then expanded to include crystallization to recover metal salts for possible reuse. Economic and environmental advantages of the procedures include recovery of acids for reuse, simplification or elimination of the disposal of waste solutions, and possible recovery of metals. Industries expected to benefit from such applications include galvanizing, electroplating, sand leaching and any where metals are cleaned in acid solutions. Currently a modular system has been assembled for recovery of several different spent acid solutions.

Jan 1, 1995

By M. Huang

A conductivity-based sensor for on-line measurement of free acid was recently built. This sensor is suitable for high ionic strength solutions and its corrosion-free operation is based on induction currents. It has been tested against literature data and measurements made using a previous developed contact-type conductivity cell, with an average difference within 1%. The electrical conductivities of H2SO4?H2O, H2SO4?MgSO4?H2O and NaCl?Laterite-H2Osolutions at temperatures up to 250 °C were discussed. It was found that the solution conductivity depends on various factors, such as the electrolyte concentrations, the type of electrolytes, temperature and the amount of dispersions. A semi-empirical model was developed to account for all the factors discussed. This model was further tested on actual process solutions from the hydrometallurgy of nickel where sulphuric acid solutions containing a variety of metal sulphates and solids. The average difference between the estimated acid concentration from this model and the one from titration was generally less than 5%, which is excellent for industrial applications.

Jan 1, 2006

By Jean Goldschmidt

Recycling of fine oxidized particles of non-ferrous metals usually cannot be carried out by pyrometallurgical methods. 'Hydrometallurgy provides an alternative technology to reintroduce? the resulting products as secondary raw materials into the industrial cycle, thereby saving resources and energy while keeping the environment a little cleaner. The paper summarizes the methods employed by Hydrometal to achieve these objectives and? stigmatizes the latest counterproductive international regulations which create ever more obstacles to environmentally sound recycling.

Jan 1, 1995

By Tom McCullough

The purpose of this paper is to discuss the implementation and results derived from installing oxy-fuel burners in a l80 ton copper reverbatory melting furnace. Specific results will be discussed in the areas of melt chemistry, furnace modifications, productivity, process enhancements, and the combustion system capabilities.

Jan 1, 1996

By Tianzu Yang, Weifeng Liu, Lin Chen, Wei Chen, DUCHAO ZHANG, HUI XIAO

Carbonaceous refractory materials are widely accepted in many reducing smelting processes such as iron and ferroalloys. Oxidizing processes such as copper concentrate smelting traditionally use magnesia and/or alumina/silica refractory materials. The main objection to the use of carbon-based refractories as the exposed working lining in oxidizing applications is the potential for free oxygen to react with the carbon at high temperature, which could rapidly degrade the refractory lining. In 2013, Outotec and GrafTech conducted joint trials of a thermally conductive, carbonaceous lining for smelting copper concentrates in the Outotec® pilot-scale top-submerged-lance (TSL) furnace in Dandenong, Australia. This testwork had two equally important goals; to demonstrate the ability of carbon refractories to withstand oxidizing process conditions, while ensuring that neither furnace operating conditions nor process stability were negatively affected by the refractory material. The paper discusses the input parameters of the trials, key observations during the testwork program, and the results and conclusions from both process and refractory design standpoints.

Jan 1, 2016

By Nobuo Kikumoto

Recently, the treatment of industrial waste materials has been a serious social problem here in Japan. Filling them in ponds is now strictly prohibited due to a limited land area and incineration method is also regulated as not to generate DXN. In these conditions, Onahama Smelter has begun to treat shredder dusts (SD) of car at reverberatory furnaces to recover various metals such as copper, gold, silver and palladium without generation of DXN. The total volume of these dusts is expected more than 1 million metric tonnes a year in Japan. Onahama Smelter is now planning to treat about 20% of them in the near future by using tonnage oxygen. In this paper, the heat balance, control method of DXN and treatment of these dusts in reverberatory furnaces are described. DXN : Dioxin (The generic term of PCDD and PCDF)

Jan 1, 2000

By V. M. Lsoitko

Statistical methods of technological mineralogy are used to model processing flowsheets in order to improve ore dressing efficiencies. The procedure involves determining geological and mineralogical characteristics of ores, classifying ore types and metallurgical procedures, and developing computer programs to interpret essential mineralogical parameters from on-stream analysis data. The on-stream analysis data include magnetism, radioactivity, luminescence and assays. The data are interpreted by computer and appropriate adjustments are made automatically in the plant.

Jan 1, 1989

By Singareddy R. Reddy, Ramana G. Reddy

"The Margules equation is used for interpreting excess Gibbs energy of several ternary systems. An expression for the activity coefficient of a dilute solute, 2(oxygen), in a binary solvent 1-3 is derived. It is used to calculate the logarithmic activity coefficient of oxygen in Pb-O-Gu, Pb-O-Bi, AgO- Sn, Pb-O-Sn and Ag-O-Pb metallic systems. Self interaction parameter of the solute is derived from the partial Gibbs energy of solute using constant compositional path. The derived equation is used successfully to deduce the self interaction parameter of oxygen in Pb-O-Gu and Pb-O-Bi metallic systems. The predicted thermodynamic parameter data i.e activity coefficient and self-interaction parameters are in an excellent agreement with the experimental data and also our predictions are far more accurate than the predictions made by other models.1 IntroductionThe nature of solute interactions such as oxygen, nitrogen and sulfur with the metallic solutions are important for a number of chemical and metallurgical processes. Several theories [1-23] have been developed to evaluate fundamental thermodynamic properties of solutes constituting two elements. The activity of solutes has been calculated using statisticalor quasi- chemical approach.Wagner's [4] Ideal Solvent Model is based on one energy parameter to describe the compositional dependencies of the activity coefficient of nonmetallic solutes such as oxygen in binary metallic solutions. This model depends on a constant energy of interaction for the exchange of atoms from the coordination shell of an oxygen atom to the shell of an interstitial site and cannot account for properties of strongly interacting systems [4]. Therefore, several attempts have been made to improve the Wagner's model for the strongly interacting systems. [10-16]."

Jan 1, 1996

By David B. George

Kennecott recently completed an $880 million modernization and expansion of its smelter and refinery to process all concentrates from the Bingham Canyon mine. This is the first application of Kennecott-Outokumpu Flash Converting. Molten material movement by overhead cranes is eliminated and high levels of oxygen enrichment result in very low process gas volumes and exceptionally control of sulfur oxide emissions. All existing in-plant hygiene, safety, and environmental regulations will be met and the smelter is positioned for anticipated more stringent future regulations. Sulfur capture is 99.9 percent resulting in sulfur dioxide emissions less than the 112 kg/hr Air Permit limit, making the smelter the cleanest in the world.

Jan 1, 1996

By C. A. Summers

The U.S. Bureau of Mines applied process mineralogy to investigate a lead and zinc deposit located near Story Creek, Colville Mining District, Alaska. Mineralization is hosted by the Kayak Shale in veins, veinlets, and breccia. Sphalerite and galena, with supergene anglesite, occur in symmetrical quartz veins and between breccia clasts. The study sample analyzed 2.11 percent Pb, 5.37 percent Zn, 0.014 percent Cu, and 1.2 oz/ton Ag. Analyses of crushed products showed that 33 percent of the sample weight, and more than 50 percent of the Pb and 65 percent of the Zn, are in the minus 850 um fraction. Liberated grains of sphalerite and galena were found in crushed products finer than 300 um. Beneficiation tests indicate the material is amenable to processing by traditional gravity and flotation techniques.

Jan 1, 1991

By Sergei A. Degterov

A thermodynamic database for the slag, matte and liquid copper phases in the Cu-Ca-Fe-Pb-Zn-Si-O-S system has been developed for the ranges of compositions of importance to the production of copper. When used with the Gibbs energy minimization software and other databases of the F*A*C*T thermodynamic computing system, this database will permit the calculation of matte-slag-copper-gas phase equilibria that take place during copper smelting and converting. The calculations reproduce within experimental error limits all available experimental data on phase diagrams, activities of components, enthalpies of mixing, matte - alloy miscibility gap and tie-lines. The calculated solubilities of Cu in both S-free slag and slag equilibrated with matte are also in good agreement with experiment under all studied conditions, such as at SiO2 saturation, in equilibrium with Fe, Cu or Cu-Au alloys, at fixed oxygen or SO2 partial pressures and at different contents of Pb, Zn and CaO in the slag. Sulfide contents (sulfide capacities) of the slags are predicted within experimental error limits. The distribution of Pb and Zn among matte, slag, copper and gas has been calculated. The calculations are in good agreement with experimental data and predict the distributions under conditions which are difficult to study experimentally, such as at magnetite saturation or under various oxygen partial pressures and iron to silica ratios in the slag.

Jan 1, 1999

By P. C. Chaubal

The overall kinetics of oxidation of single partic1es of chalcopyrite have been studied for temperatures up to 1273 K. The experiments were conducted in a stationary bed reactor using a non-isothermal technique. Any mass and heat transfer effects on the kinetics of oxidation were eliminated by using a high-enough gas flowrate. Up to temperatures of 873 K, pore-bl1ocking kinetics were applicable, whereas above 873 K, power-law kinetics gave a satisfactory fit of the data. The activation energy was 215 kJ/mol below 754 Kand 23.7 kJ/mol above 1,060 K. Predominance area diagrams were constructed at various temperatures and used in conjunction with X-ray analyses of partially oxidized samples to determine the intermediate phases formed during the reaction. The analysi1s also provides a justification for the kinetic models used. The results indicate that the reaction rate is first order with respect to oxygen concentration and inversely proportional to the square of the particle size throughout the ranges of temperature studied.

Jan 1, 1985

By David G. C. Robertson

A new approach is described for the calculation of the kinetics of metal/slag, metal/slag/gas, and metal/matte/slag/gas reactions. The algorithm assumes that equilibrium is achieved at the interface between phases, and uses an equilibrium solver (such as SOLGASMIX) to compute the equilibrium state at the interface at each time step during the reaction. For multiple phase systems a number of unit operations, representing the different phases and interfaces, must be connected together in a reasonalbly complex manner, and the METSIM software package has been utilized for this purpose. The new approach is superior to the SMAK software developed by the author and his co-workers over the past decade, for the reasons discussed in this paper.

Jan 1, 1995

By Xuling Chen, Zhiyun Ji, Min Gan, Tao Jiang, Liang Yin, Xiaohui Fan

Straw char exhibited considerably faster burning speed than coke breeze for its porosity, which significantly degraded sinter quality when it replacing coke breeze as sintering fuel. In this investigation, preforming technology has been employed to densify raw straw. The properties of straw char preformed show that its density was increased, and the structure was also densified, which made the difference of combustibility between the straw char and coke breeze smaller. The proper preforming temperature, residence time and pressure were 200℃, 1min and 120MPa respectively. Sinter pot trials show that the product carbonized from preformed straw made the proper replacement ratio to coke breeze increase from 20% to 40%, and the emission reduction of SOx, NOx in flue gas increase from 11.50%, 14.15% to 37.85%, 23.60% respectively, compared with non-preformed straw char.

Jan 1, 2015

By Gabriel A. Torma

This paper provides infonnation on selected technologies available for remediation of metal contaminated soils and industrial effluent solutions. Because some of the industrial sites are contaminated with organics (solvents, gasolines and oils), an effort has been made to introduce the most frequently used cost-effective cleanup methods, such as "bioventing" and "composting." The microorganisms involved in these processes are capable of degrading organic soil contaminants to environmentally harmless compounds: water and carbon dioxide. Heavy metals and radionuclides contaminated mining and industrial sites can be remediated by using adapted heap and dump leaching technologies, which can be chemical in nature or bio-assisted. The importance of volume reduction by physical separation is discussed. A special attention is devoted to the remediation of soils by leaching (soil washing) to remove heavy metal contaminants, such as chromium, lead, nickel and cadmium. Furthermore, the applicability of biosorption technology in the remediation of heavy metals and radionuclides contaminated industrial waste waters and acidic mining effluent solutions was indicated.

Jan 1, 1996

By Rey B. Marquez

This paper introduces and outlines the implementation of Reliability Centered Maintenance (RCM) at Phelps Dodge Hidalgo Inc. By using a disciplined approach to the everyday maintenance functions, a proactive strategy is being developed which "raises the bar" for plant maintenance. The main objectives are: integration of Operations and Maintenance partnerships, transformation of maintenance practices from a reactive to proactive mode through the introduction of a progressive Predictive/Preventive Maintenance program (PDM/PM) paradigm changes, increased management support of maintenance functions, introduction of new indices and root cause analysis, updated; training, and definition of RCM components. RCM is the vehicle being utilized to reach the higher level of equipment availability and utilization. However, the ultimate goal is to venture beyond RCM and into the new frontier of Total Maintenance Management (TMM).

Jan 1, 1998

By Elli Miettinen, Markku Lahtinen, Ilkka Kojo

"The recent trends of decreasing energy consumption and environmental emissions and utilization of economies of scale are strong drivers favoring continuous copper converting processes. Flash Converting benefits from low off-gas volumes and low investment and operational costs for off-gas treatment. Separate matte and blister furnaces allow the adaptation to concentrate quality changes and flexibility in layout and maintenance.The stationary blister copper bath in Flash Converting furnace is less aggressive to the furnace linings than agitated processes, resulting in low refractory consumption, long campaign life and high on-line availability.Copper Flash Converting has been successfully applied in Kennecott with a campaign life now exceeding five years. A second FCF was started at Xiangguang Copper in China in 2007. The process itself is proven, as its features are similar to those in FSF, Direct-to-Blister and Direct Outotec Nickel Flash Smelting (DON), with one significant difference: it is the easiest of all to operate.The paper presents differences between continuous Flash Converting and conventional converting based on recent experiences and studies."

Jan 1, 2009

By P. Louis

Gécamines is the world largest cobalt producer with about 60 % of the Western World production. During the last ten years, its annual production varied from 5,400 to 14,600 t/year. The actual cobalt production capacity of Gécarnines is 18,000 t/year and could be increased in the near future if necessary. Cobalt is presently produced at the Shituru plant by an old in-pulp electrolysis process and in Luilu, by electrolysis of a clear weakly acidic solution. The Shituru Cobalt quality is lower than the Luilu one. For that reason, part of the Shituru Cobalt is fire refined and cast into granules. Large efforts have been succesfully accomplished to improve the cobalt quality. This has been made possible by a better knowledge of the purification processes and of the electrolysis parameters.

Jan 1, 1988

By R. S. Krarner

Fly ash, a by-product of coal burning power plants, poses a major problem for the utility industry since most fly ash must be landfilled. These quantities may represent as much as 20% of the total material going into landfills. A major problem with fly ash utilization is that although the ash consists of useable components, ash composition can vary depending on the types of coal burned and plant operating conditions. Ash is first characterized using SEM, image analysis, and chemical methods. Processing techniques were developed to separate ash into various components including cenospheres, magnetic spheres, carbon, and clean ash. These products are again evaluated for various utilizations before being used to produce valuable products such as mullite, activated carbon, fillers in plastics, and concrete.

Jan 1, 1994

By D. M. Jones

Dust generation data have been obtained from 19 industrial Outokumpu flash furnaces. Statistical analyses of the data have been carried out and the most significant factors affecting dust generation evaluated. The results indicate that dust production may most effectively be minimized by: 1) Minimizing the distance between the molten slag and the furnace roof 2) Optimizing burner design and combustion parameters.

Jan 1, 1996