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By Myung Bae Kim, Yong Hack Lee, Woll Seung Lee

The Slag Fumer is the first Ausmelt furnace system adopted at the Onsan Refinery of Korea Zinc. This plant continuously treats the QSL lead smelting slag in the molten state. It has developed progressively since its first commissioning in October 1992 and has generated a confidence that it can produce an environmentally acceptable slag for use in cement manufacture and recover the zinc and lead in the slag as a fume oxide. This paper provides the operating experiences accumulated during the last eight years of operation, a summary of problems and solutions, and the current status of the operation.

Jan 1, 2000

By Kurt Westerlund

Three. years operating experience of the FLUXFLOW waste heat boiler (WHB) 20.000 nm /h at Boliden Ronnskar Sweden on a TBRC smelting palena (PbS). Operating experience from the Kivset flash WHB 11.900 nm /h at Samim, Porto Vesme, Sardinia, Italy. Conceptual features of the 93.600 nm3 /h FLUXFLOW (WHB) on the Isasmelt smelting in melt furnace for 180.000 t Cu/a at Mount Isa, Australia.

Jan 1, 1992

By Patrick R. Atkins

Energy issues will have increasing impacts on decision making in all facets of society over the next few decades. Industrial users of energy and producers of products that affect energy use must be fully aware of the implications of their processes and products on the energy situation. This paper describes a model that has been developed for the aluminum industry that allows scenarios to be evaluated to gain improved understanding of possible implications for our businesses. A brief overview of the model is provided.

Jan 1, 2006

By Habib Saridikmen

In this experimental study the effects of slag composition on the phosphide capacities of the slag as well as on the phosphorus distribution ratios between the slag and metal phases encountered in ferromanganese smelting have been determined at 1500°C under carbon monoxide atmosphere. The distribution results were employed to calculate the phosphide capacities of the SiO2-Al2O3-CaO-MgO-MnO slags in equilibrium with the Mn-Fe-Si-Csatd.metal phase. The classical gas-slag-metal equilibrium-quenching technique was employed using CO gas atmosphere and graphite crucibles to saturate the metal phase with respect to carbon. The phosphorus distribution ratio increased from 0.045 to 0.375 when the slag basicity increased from 0.72 to 1.39. As expected, the distribution ratio decreased from 0.375 to 0.105 when silica increased from 37 % to 45.8% in the slag phase. The phosphide capacity values were calculated by using the results of experiments. Empirical relationships were developed to express the phosphorus distribution ratios and phosphide capacities of the above slags.

Jan 1, 2006

By A. V. Tarasov

Regeneration of carbide waste from hard-alloy (sintered carbide) manufacture is an important scientific and technical objective aimed at improving the degree of recycling of rare metals (W, Co, Ta, Ti, Nb). Currently, the degree of recycling of those metals does not exceed 25% to 35% of their total production even in industrially developed countries. This is attributed to a significant extent to the substantial drawbacks of the technologies applied for their processing (environmental pollution, limitations to the use of regenerated products for important applications, sophisticated equipment to be used). An innovative environmentally sound technology has been developed in the Institute of Metallurgy of the Russian Academy of Sciences (IMET RAN) for processing of carbide waste of WC, TiC, TTC and other carbides using asymmetric alternating current of industrial frequency (the electrolyte used for this purpose is nitric acid solution). The current efficiency under optimal conditions is as high as 96% to 98%. The process has been tested on bench scale. The following commercial-grade products are obtained: pure ammonium paratungstate, tungstic acid, cobalt oxide, titanium dioxide and tantalum-niobium concentrate. The total metals recovery is 98% to 99%.

Jan 1, 2006

By Kamal Adham

Hydrochloric acid is used as lixiviant in such hydrometallurgy processes as synthetic rutile production and nickel extraction. The intermediary metal chloride is normally roasted to release gaseous HCl and a solid metal oxide. A large amount of fuel is required for this thermal regeneration, mainly to vaporize the water content of the feed solution. To conserve fuel, some energy recovery from the off-gas is currently achieved, but the fuel costs can further be reduced by process optimization and energy recovery from the gaseous, aqueous and solid products of the regenerator. Here, first the existing limitations to fuel efficiency in the industrial scale HCl regeneration roasters are described. Then, for the case of a dilute feed solution, options for pre-evaporation and fuel minimization are modeled and compared. Finally, energy recovery technologies including heat pumps, acid heat exchangers and solid waste heat boilers are described, and their potentials as the heat source for pre-evaporation of the feed are evaluated.

Jan 1, 2003

By Graeme Miller

The geotechnical characteristics of the ore are important in understanding the kinetics of a copper heap leach. These characteristics can indicate potential problems and can be used to determine the semi-quantitative changes in field kinetics as compared with column kinetics. The application of this approach allows a more rigorously based determination of ?scale up factors? than has been the case the date. The shrinking core model has been shown to be a poor predictor of leach kinetics based on the crushed ore size distribution. However the model itself is a very useful tool to analyse commercial heap data. Significant geotechnical parameters such as: bulk density / stress characteristic, limit moisture capacity and particle density are used to determine the effect of changes on the diffusion controlled leach rate. By consideration of the geotechnical reaction of the ore mass the leach rate changes are related to changes in these variables. Analysis of commercial heap data has indicated effective diffusion lengths of up to ten times the largest particle size.

Jan 1, 2003

By E. Munnik

The Chambishi Metals Cobalt Plant in Zambia has recently installed a novel oxidation/precipitation pressure leach process as part of the COSAC (Cobalt from Slag and Copper as by-product) Project. An iron-cobalt-copper alloy, produced by the carbothermic reduction of slag, is atomized and pumped to the COSAC Leach Plant, where cobalt and copper are recovered as dissolved sulphate salts, and iron is rejected primarily as hematite. Cobalt and copper are subsequently recovered as cathode metal in the existing Chambishi operation by conventional electrowinning. This paper examines the challenges faced during the design and subsequent successful commissioning of the COSAC Leach Plant.

Jan 1, 2003

By Zenon R. Llanos

"The disposal of spent hydroprocessing (HDP) catalysts in the petroleum refining industry has been a concern in the past due to their classification as listed hazardous wastes. However, because these catalysts have higher metal concentrations than regular ores, and the recent surge in prices for molybdenum, vanadium, nickel and cobalt what used to be considered as a liability for generators is now viewed as a valuable renewable source of strategic metals. At the same time the generation of spent catalysts has steadily risen due to new environmental regulations for low sulfur fuels and an increased appetite of gasoline consumers. This paper will examine spent catalyst market and the role played by Gulf Chemical & Metallurgical Corporation in the reclamation of metals over the last sixty years. Introduction Hydroprocessing (HDP) catalysts are used in petroleum refineries for two main applications: desulfurization and cracking. The catalyst support is alumina or mixtures of alumina and silica. Active metals include molybdenum, nickel, cobalt and tungsten. The selection of catalysts depends on the application and sometimes the cost. The life cycle of HDP catalysts is represented in Figure 1. The catalyst cycle in a reactor varies from continuous to one-two years. Catalysts used in various refining processes are deactivated by coke, sulfur, vanadium and other impurities in the refinery feedstocks and become spent. Refineries can optionally send the spent catalysts for regeneration, metals reclamation or landfilling. Catalysts used for refining heavy crudes often can not be regenerated. Catalysts used with light oils can be reused twice or three times after regeneration. When the option for regeneration is not viable, spent catalysts are send metal reclamation facilities or landfills."

Jan 1, 2008

By Hong Yong Sohn

On the occasion of this symposium in my name, I reflect upon the contributions of my academic mentors and early associates who helped shape my professional career. I was fortunate to have these people around me during my graduate work and at the start of my professional career. In forming my view of the technical field and career, they represented academia, research institutions, industry, and different parts of the world.

Jan 1, 2006

By Anatoly Sudnev, Vladimir Skorohodov, Igor Kudryavtsev, Boris Radionov, Dmitriy Panov

"In cobalt production technology at a stage of solutions purification manganous cake (slime) basically containing hydroxides of the specified metals is formed. The possibility of full cobalt recycling in the basic technology of metal production at slime processing with generation of pure manganous compounds is shown. After slime dissolution in sulfuric acid in the presence of reducers the solutions containing cobalt, manganese, nickel and other nonferrous metals are formed. Optimum conditions of selective precipitation major part of cobalt by sodium hydroxide from the obtained solution are defined, thus more than 95% of manganese are remained in the solution. The cobalt precipitate is directed to the basic technology and the solution is purified by sorption. The most effective sorbents are chosen, optimum modes of its use are found. Examples of manganese recovery from the purified solutions as MnO2, MnCO3, Mn(OH)2 with a ratio manganese : impurities more than 3000 are presented.In the processes of hard alloys manufacture and processing of cobalt-bearing primary raw materials various cobalt-manganous slimes are formed. After leaching by solutions of mineral acids the problem of cobalt and manganese separation becomes an actual. The common way of metals separation in a solution is the Shreyber’ alkaline method allowing rather selectively to precipitate of cobalt hydroxide by sodium hydroxide. However this way does not allow separating completely target metals because of transfer of some manganese in the hydrated precipitate, even at its rather low content.In the given work the results of researches to improvement of a traditional way by inclusion to hydrometallurgical technology of operation of sorption separation of the specified metals are presented. The main goal is definition of conditions to achievement of the complete removing cobalt at hydrolysis with the minimum sedimentation of manganese and the subsequent additional recovery of cobalt by ionites from the obtained solutions."

Jan 1, 2008

By R. W. Lawrence

A high rate biological reduction technology has been developed to provide low cost hydrogen sulphide for various uses in water treatment and metallurgical processes. Commercial operations produce sulphide safely at a fraction of the cost of chemical sulphide. The biologically produced H2S is used for treatment of acid wastewater and selective metal recovery whereby metals present in wastewater streams are recovered in high grade metal sulphide concentrates that are sold to smelters. The combination of biological H2S production and selective metal recovery is currently marketed under the process name BioSulphide-Thiopaq. The process can be applied on a stand-alone basis or in conjunction with a conventional lime water treatment. Process advantages include: reduced lime treatment costs, reduced volume of waste sludge free of toxic metals leading to reduced long term environmental liabilities, selective recovery of metals and, in some cases, net profit from water treatment achieved through the sale of metal concentrates. Three case studies are presented to provide examples water treatment and metal recovery: the Caribou Mine, New Brunswick; the Phelps Dodge Bisbee operations, Arizona; and Falconbridge?s Raglan nickel mine in Quebec. A fourth case study is presented to highlight environmental control for treatment of ARD in the Leadville mining district of Colorado. Process flowsheets, capital and operating costs are presented for the four case studies

Jan 1, 2003

By M. Olper, M. Maccagni, C. J. N. Buisman, C. E. Schultz

The key point of the CX-EWS process is the conversion of lead compounds, contained in the active mass of spent batteries, into lead sulphide. The obtained lead sulphide is leached with ferric fluoborate electrolyte to dissolve lead and oxidize the sulphur from sulphide to the elemental form. The lead-rich solution is fed into a diaphragm electrolytic cell depositing lead and regenerating ferric fluoborate. The introduction of sulphate reducing bacteria technology in the sulphidization step of the battery paste improves dramatically the economics of the CXEWS process, reducing the costs of chemicals, avoiding gypsum disposal and minimising the unit operations of the process. This paper describes in detail this technology change with reference to the economics of the process.

Jan 1, 2000

By E. L. Frueh

AMAX Base Metals Research & Development, Inc. has developed a process for treating copper-nickel mattes to produce copper cathodes and a pure nickel sulfate solution. In this process, the input matte is preleached in a copper sulfate electrolyte bleed solution so as to dissolve nickel from the matte and cement copper from solution. The preleach leaves a substantially pure nickel sulfate solution. The residue from the preleach is roasted to less than about one percent sulfur. A portion of the calcine is leached with sulfuric acid to make a copper sulfate solution for input to the tank house. The residue from this leach and the remaining calcine are smelted to form a bimetallic (copper/nickel.) anode. The anodes are electrolytically refined and copper is preferentially deposited on the cathode while the nickel reports to the electrolyte, A bleed stream is taken from the electrolyte and used in the preleaching of the input matte. This process produces high purity metal streams while consuming less energy and smaller amounts of reagents as compared with other matte processes.

Jan 1, 1983

By Hong Yong Sohn

On the occasion of this symposium in my name, I reflect upon the contributions of my academic mentors and early associates who helped shape my professional career. I was fortunate to have these people around me during my graduate work and at the start of my professional career. In forming my view of the technical field and career, they represented academia, research institutions, industry, and different parts of the world.

Jan 1, 2006

By Jitka Jandová

A laboratory process based on simple and environmental friendly operation, aimed at recycling of spent Li/MnO2 batteries, is described in this study. This process involves roasting Li/MnO2 batteries in a vacuum furnace at 650°C, followed by selective leaching Li2CO3 from calcined electrode material in distilled water at ambient temperature and controlled crystallization of pure Li2CO3.

Jan 1, 2006

By Gustavo A. Munoz

Activated carbons owe their adsorption capacities to their extensively developed pore network structure. As a result, these adsorbents generally exhibit high specific surface areas. Currently, granular activated carbons produced from coconut shells are traditionally used for gold recovery by adsorption from cyanide leaching solutions. Magnetic activated carbons (MACs) for gold recovery from cyanide solutions produced from sources other than coconut shells have been developed at the University of Utah by mixing a magnetic precursor with a carbon source, and treating the mixture under controlled conditions of temperature and gas phase composition. The pore size distribution of the activated carbons is dependent on the degree of activation, among other factors. The significance of the MAC pore size distribution on gold adsorption kinetics and gold adsorption capacity is presented.

Jan 1, 2003

By Joseph J. Poveromo

Technical progress in ironmaking will be discussed in three sectors: blast furnace ironmaking, direct reduction and alternative ironmaking to feed electric arc furnaces and ironmaking for waste oxide processing. The contributions of iron ore producer, Quebec Cartier Mining, in each sector will be outlined.

Jan 1, 2006

By A. V. Tarasov

Based on the data available in the literature and the practical experience of new metallurgical plants, a method has been proposed and relevant studies conducted for metallurgical processing of zinc sulfide concentrates. Process conditions and parameters have been identified, which ensure high levels of recovery of zinc into solution. This is achieved by leaching concentrates under the normal pressure at a temperature of >90°C in the presence of ferric iron ions. Sulfide sulfur is converted to elemental sulfur in this process. To produce elemental sulfur it is necessary to maintain oxidizing conditions in the system, characterized by a positive Eh value. In order to eliminate the interfering effect of elemental sulfur formed in the process, it is possible to add surfactants into the concentrate pulp. The proposed technology has certain advantages as compared with the high-temperature pressure leaching and is considered as a basic technology to be applied to increase zinc production at one of the Russian zinc plants.

Jan 1, 2006

By Ian M. Ritchie

Cementation or metal displacement reactions such as Cu2+ + Fe Cu + Fe2+ are among the oldest known hydrometallurgical reactions. They are still used in the recovery of some metals and in the purification of process liquors and waste water streams. However, they are often more complex than the stoichiometric reaction would suggest because they involve the simultaneous deposition of one metal onto a second which is dissolving. For example, sometimes a cementation will not take place, even though it is thermodynamically favoured. On other occasions, a cementation reaction will start but come to a halt as the depositing metal blankets the reacting surface. On yet other occasions, side reactions, catalyzed by the deposit, can be important. In this paper, the electrochemical basis of cementation reactions is described. The conditions for each of the complications encountered in these reactions are described and illustrated by examples drawn from a number of hydrometallurgical processes. The cementation reaction between activated carbon and gold thiosulfate is also briefly described, this reaction being unusual in that no dissolution of the carbon occurs.

Jan 1, 2003