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By Gary Kordosky

Equilibrium modifiers, first introduced into copper solvent extraction reagents in the late 1960?s, are widely used. The properties of various equilibrium modifiers with respect to copper extraction, selectivity, reagent stability and entrainment are discussed and some conclusions are drawn relating the structure of the modifier to the properties of the modifier. A new highly selective, low viscosity modifier is also introduced.

Jan 1, 2003

By Chi Ru?an

Sollutions of ammonium chloride, nitrate and sulfate were studied in extraction of rare earths absorbed on a low-grade, kaolilnitic ore recently discovered in southern China. The results of percolation leaching tests and the recovery of the rare-earth values from these solutions are presented.

Jan 1, 1989

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 David M. Beckwith

Increased globalization and outsource manufacturing complicate the procurement and enforcement of intellectual property rights on a worldwide basis. Recent legislative and case law developments in the United States highlight the importance of a multinational intellectual property strategy. IP lawyers David Beckwith and John Hankins will discuss planning and pitfalls in this rapidly changing trans-border environment. Topics to be discussed include harmonization with international patent laws, protecting your technology and market space with a comprehensive approach to IP, and patent enforcement issues relating to import/export of products and components in the United States.

Jan 1, 2006

By Ali Unal, Ali I. Kahveci

Alcoa developed a fractional crystallization process some 30 years ago as a method to purify aluminum. Depending on the purity of feed metal, it has been commercially used to make 3N7-6N purity aluminum. As an extension of this technology, Alcoa has experimented with purifying various aluminum alloy scrap for the purpose of recycling. Purified aluminum alloy scrap can be reused for making the same alloy. This presentation will discuss Alcoa fractional crystallization technology and its application to alloy scrap processing. Process capabilities and the partitioning of eutectic and peritectic impurities during fractional crystallization will be discussed for the alloy systems investigated.

Jan 1, 2000

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 Gi-Chun Han

This study focused on stabilization of heavy metals and removal of chlorine in MSWI bottom ash by artificial carbonation with washing. Artificial carbonation was carried out by applying CO2(g) injection in washing for fractions above and below 4mesh for reuse as construction materials like aggregate, As a result, carbonation with washing could satisfy Korean environmental regulation and remove chlorine in bottom ash more effectively by resolving residual friedel?s salt(3CaOAl2O3CaCl210H2O).

Jan 1, 2006

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 F. J. Tavera

A study on the electro kinetics of lead carbonate, silica, and alumina, in aqueous media was carried out at different pH values. The behavior of potential was determined for these species in the pH range between 3 and 12. Homocoagulation of lead carbonate in aqueous media is analyzed at its isoelectrical point. Lead carbonate heterocoagulation is analyzed with silica, alumina, and silica ? alumina mixtures at low pH values. The experimental results are considered for their possible application to treat residual water polluted with lead.

Jan 1, 2006

By Mark F. Vancas

Virtually every new process plant project goes through the ?Feasibility Study? phase before actually being built. The Feasibility Study is used by the owners and the bankers to evaluate the economics of the project and determine whether or not the proposed investment meets their respective investment guidelines. With a positive result, the project is approved and goes to construction and operation. Then, the actual costs are incurred and these actual costs may or may not agree with what the Feasibility Study predicted. Just how good have Feasibility Studies been? This paper looks at various projects and compares predicted to actual results and also gives information on how to spot a poor feasibility study.

Jan 1, 2003

By Joe Milbourne

The potential for treating copper-nickel-cobalt-platinum group metal concentrates by a fully hydrometallurgical route is discussed. Processes specifically developed for treating these feeds and the potential application of the processes developed for the treatment of chalcopyrite copper concentrates are included in the evaluation. Block flowsheets are provided and the technical characteristics of various processes are compared. The current state of development for each process is summarized and probable economic impacts of the technical features are qualitatively assessed. Perceived risks and rewards associated with each technical concept are provided in the conclusions.

Jan 1, 2003

By John O. Marsden

The past fifteen years have seen a number of important developments in copper hydrometallurgy, including the commercial application of biological heap leaching of secondary (chalcocite-dominant) copper ores, the commercial demonstration of chalcopyrite concentrate leaching technology using pressure leaching and biological processes, and the application of novel configurations of solution extraction circuits. Significant emphasis is now being placed on the development of effective stockpile leaching practices for primary ores (chalcopyrite and bornite-dominant mineralization). Some of these developments have been highly successful, and will pave the way for further development and commercialization. Others have been less successful. These developments are reviewed in the context of the metal price cycle and trends for the future are identified.

Jan 1, 2006

By John O. Marsden

The past fifteen years have seen a number of important developments in copper hydrometallurgy, including the commercial application of biological heap leaching of secondary (chalcocite-dominant) copper ores, the commercial demonstration of chalcopyrite concentrate leaching technology using pressure leaching and biological processes, and the application of novel configurations of solution extraction circuits. Significant emphasis is now being placed on the development of effective stockpile leaching practices for primary ores (chalcopyrite and bornite-dominant mineralization). Some of these developments have been highly successful, and will pave the way for further development and commercialization. Others have been less successful. These developments are reviewed in the context of the metal price cycle and trends for the future are identified.

Jan 1, 2006

By R. J. Wesely

Non-ferrous smelters traditionally have a hot gas handling system. In these systems, the dust is captured as a dry material which is often recycled to the process. Some smelters use wet gas cleaning methods with the recovery of the dust as a wet sludge. Although this sludge can be recycled to the process, in some cases it is preferable to dispose of the sludge. This paper will discuss the disposal methods available and specifically will deal with one type of sludge which has a high arsenic and high lead content. Problems with this sludge were investigated and methods were tested with the aim of stabilizing the sludge so that it passes the EPA TCLP test. Results of the laboratory tests are given.

Jan 1, 2000

By F. J. Tavera

The colloid flotation of lead carbonate precipitates in aqueous media is studied at a pH of 7. The flotation system consisted of five spargered flotation cells in a serial array. The flotation system was operated under controlled conditions of superficial air velocity, superficial liquid velocity, frother concentration, and collector concentration. The measured variables were gas hold-up, bubble size, superficial bubble surface flux, and lead recovery (reported to the concentrate). The experimental data show that it is possible to separate as much as 97% (w/w) lead from the aqueous media when the superficial gas velocity is 1 cm/s and the superficial liquid velocity is 0.19 cm/s.

Jan 1, 2006

By John O. Marsden

The past fifteen years have seen a number of important developments in copper hydrometallurgy, including the commercial application of biological heap leaching of secondary (chalcocite-dominant) copper ores, the commercial demonstration of chalcopyrite concentrate leaching technology using pressure leaching and biological processes, and the application of novel configurations of solution extraction circuits. Significant emphasis is now being placed on the development of effective stockpile leaching practices for primary ores (chalcopyrite and bornite-dominant mineralization). Some of these developments have been highly successful, and will pave the way for further development and commercialization. Others have been less successful. These developments are reviewed in the context of the metal price cycle and trends for the future are identified.

Jan 1, 2006

By C. Camurri

Results from the Metallurgical Department of Universidad de Conception showed that fire-refined copper could be rolled without previous remelting for deoxidation. The goal of this work is to determine the rheology of fire-refined copper from tensile tests at different temperatures and strain rates, and Ford plane compression tests. All that in order to simulate and calculate rolling process variables. For rheology hardness coefficients, n variables between 0.28 at 600°C and 0.46 at ambient temperature are obtained. The sensibility coefficient for strain rate m varies between 0.056 at 600°C and 0.006 at ambient temperature. The activation energy for plastic flow Q in the considered temperature range is 1436 cal/mol.

Jan 1, 1999

By W. H. Jay

Sulphide-containing minerals, particularly iron, lead to acid formation. In turn, the acid generates effluents such as copper acid drainage (AMD). The Berkeley Pit in Butte, Montana, USA and Mt Lyell in Tasmania, Australia, represent just two of many sites throughout the world for which acceptable treatment methods are required. In the gold cyanidation process, the presence of copper creates both a significant cost impediment and a potential environmental hazard. The tailings dam failure at Baia Mare in Romania which led to the release of copper and zinc cyanides created a major environmental disaster. The application of non-toxic water soluble polymers and ion exchange resins to selectively recover copper from AMD solutions, and the in-plant treatment of copper cyanide solutions and slurries to recover copper and recycle cyanide to prevent cyanide entering the tailings impoundment will be discussed. The economics of the various processes will be highlighted.

Jan 1, 2003

By I. Van de Voorde

In this paper, results are presented concerning the search to implement Supported Liquid Membranes (SLM) Technology for the recovery of copper, nickel and zinc from electroplating and other effluents to prevent metal waste. A study of the influence of the individual parameters and of their combined effect on mass transfer in small-scale laboratory equipment has been performed, enabling to set forward the appropiate operating conditions for a pilot plant installation. The SLM pilot plant has been tested extensively, including short and long term runs, with real process solutions. It was demonstrated that the SLM technolgy is applicable for solutions containing 800 mg/L of metal ions, but also to the treatment of solutions with low metal content of origin other than plating shops. It was demonstrated by system analysis that the recycled salts are usable to produce metal electrolytes (for example Watt's nickel bath).

Jan 1, 2003

By Miguel Olivas-Martínez

A two-dimensional computational model for the hot filament chemical vapor deposition (HFCVD) process to produce diamond films is presented. The model incorporates the transport of momentum, energy, and mass inside the reaction chamber of a HFCVD reactor. The gas-phase homogeneous reactions were represented by a simplified reaction mechanism. The gas-phase transport equations were coupled to the kinetic expressions representing the catalytic dissociation of the molecular hydrogen at the filament surface and the deposition rate of the diamond film on the substrate. The computational model was solved numerically by means of a commercial software. The model predictions showed good agreement with the experimental data reported in the literature in terms of both temperature and methyl concentration profiles along the filament-substrate center distance. Examples of the potential applications of the present formulation for the design and further optimization of the HFCVD reactor are discussed.

Jan 1, 2006