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By Song Ning

The main mineral constituents of phase-transformed chalcopyrite are CuS and FeS2. CuS is more soluble than FeS2 in an acidic CuCl2 solution with presence of excessive NaCl, so that FeS2 could be removed as solid residue from a leached solution. The experimental results showed that the efficiency of the copper leaching is heavily determined by the following two factors: a) The degree of the chalcopyrite phase transformation to CuS and FeS2 b)The concentration of Cl during the leaching, specifically whether there is enough excessive Cl existed. I t was found that when the Cl in the solution is not excessive, the slowest step of the leaching is the dissolution of Cu2Cl2.

Jan 1, 2006

By W. F. Miao

Nanocrystalline mixtures of Nd2Fe14B and a-Fe have been synthesized by mechanical milling and heat treatment. The samples exhibit isotropic behavior, with significant remanence enhancement associated with exchange coupling across the interfaces of hard and soft magnetic phases. Measurements of the effect of heat treatment on structure and magnetic behavior demonstrate the important influence of grain size on magnetic properties. The effect of alloy additions to increase the saturation magnetization of the soft phase and the magnetocrystalline anisotropy of the hard phase has also been investigated.

Jan 1, 1997

By Jean-François Domgin

This paper aims at presenting numerical results showing the impact of different parameters on the limitation of entrained slag from ladle to tundish during the ladle drainage. These parameters are process parameters, slag properties or external actuator acting directly on ladle slag behaviour. Numerical simulations based on the use of the CFD Fluent software illustrate the vortexing and non-vortexing phenomena appearing during the ladle drainage. This numerical tool validated by experimental data acquired on water model has been applied to industrial configurations. It shows that the slag properties (viscosity, surface tension?) or some modifications of parameters (slide gate opening, geometry of the ladle bottom?) have a positive effect on the slag entrainment and also on the decrease of the ladle heel. Finally, the modelling of the behaviour of an external actuator injecting some gas in the region of the nozzle reveals interesting possibility for reducing slag entrainment from ladle to tundish during the final steps of the drainage.

Jan 1, 2006

By J. de Visser, J. A. Davis

Since the mid 1970's, development of zinc electrowinning (EW) facilities has out-paced its counterparts in the copper and nickel electrowinning industries in the design of efficient, compact, and automated production plants. Recent advances in process automation have provided opportunities to increase current efficiency, productivity and cathode quality, while reducing the footprint of the plant and the number of operating personnel working on top of the cells. Usually, the practice has been to allow a totally contaminated building structure, combining the plant ventilation system with the process cooling air. As a result, facilities employing this practice are finding difficult to meet their process design criteria and the stringent labor and environmental requirements. This paper provides an overview of the problems and disadvantages associated with these older process designs. It also describes new developments in ventilation systems, particularly building design developments and cost savings that are possible when improved ventilation systems are introduced into efficient process operations. Lead-

Jan 1, 2000

By D. Ducharme, J. Lenz

Operation of the Kidd electrolytic zinc plant commenced in 1972 with a cellhouse capacity of 105,000 tonnes of zinc cathode. The original cellhouse layout consisted of 42 parallel rows for a total of 588 cells. As leaching capacity increased, the cellhouse was expanded to 630 cells. Zinc cathode was manually stripped from plant start-up until the development of a mobile automated stripping system in 1994. Machine development continued until a second unit was placed in production in 1996, from which point, 60 % of the cellhouse was being stripped with the automated system. The final phase of the project was implemented in 1999 with the commissioning of two more automated strippers. This paper describes the implementation of the automated stripping system and its impact on cellhouse productivity.

Jan 1, 2000

By R. Abel F.

In 1997, Ventanas electrolytic refinery expanded its production capacity from 215,000 to 325,000 metric tons per year. This increase in capacity has involved the treatment of anodes with different impurity contents, changing the operational strategy of the plant. On the other hand, the increasing necessity to accomplish environment conservation rules and quality assuring requirements, has led the plant operation and administration to compete in an advantageous way. The present work describes the results obtained in the startup and in the operation of the ENAMI Ventanas electrolytic refinery expansion, and shows the difficulties which have been faced in the processing of anodes of increasing complexity, in a competitive market and with environment and quality restrictions.

Jan 1, 1999

By Katsunori Yamaguchi

The zinc, lead and alumina contents in copper smelting slag are increasing with the increase in waste recycling. The recovery of base metals such as lead and zinc from copper converter slag is important from both an economical and environmental perspective. As a fundamental study of the metal recovery by reduction process, activity coefficients of ZnO and PbO in the CaO-SiO2-FeOx-5mass%AlO1.5 slag under iron saturation at 1573K are derived from the data of slag-metal equilibrium experiments. On the basis of the obtained data, the activity coefficients of ZnO and PbO in the CaO-SiO2-FeOx-5mass%AlO1.5 slag were compared with those of the CaO-SiO2-FeOx ternary system. Addition of alumina increases activities coefficient of ZnO and PbO in SiO2 rich side of the slag, and decreases them in CaO rich side.

Jan 1, 2006

By Roberto Parra

The wear and corrosion phenomena in the furnace lining of the ferrous and non ferrous pyrometallurgical processes are complex problems where chemical, interfacial and mechanical phenomena are presents. The characteristics of the processes determine the conditions to which these materials are submitted, where the thermal conditions reached during the operation is one of the most important parameter. Assuming that all the degradation phenomena are thermal activated, the rate of the different steps of the wear mechanism will depend on the thermal field in the lining. In view to apply the independent physicochemical knowledge of degradation mechanisms to the analysis and design of furnace lining the methodology of the Nodal Wear Model (NWM) was done. It combines the mathematical modelling of the heat transfer in the lining with the physicochemical control equation for the wear-corrosion phenomena. The NWM has been applied to different examples: theoretical analysis, laboratory scale test and industrial applications. We present in this paper the theoretical background of the model and two examples of applications: the sole of an electric furnace and the earth of a blast furnace.

Jan 1, 2006

By Michael S. Moats

As commercial copper electrorefineries look to expand their capacities by increasing their operating current density, the likelihood of anode passivation intensifies. To improve the industry?s understanding of the passivation phenomena, the role of anode composition was evaluated. While previous studies have focused on studying one impurity element at a time, this study was conducted using forty-four commercial electrorefining anode samples supplied by ten copper companies The passivation response of each sample was evaluated under accelerated galvanostatic conditions in synthetic copper electrowinning electrolyte at 65°C. This information allows for correlations between composition and passivation tendencies over a wide range of impurity elements and concentrations. It was found that selenium, tellurium, silver, lead and nickel accelerated passivation. It appeared that oxygen accelerated passivation when increased from 500 to 1500 ppm, but further increases did not have an effect. Arsenic was the only impurity found that inhibited passivation.

Jan 1, 2006

By Mingzhou Li, Lin Wu, Changren Tong, Fengli Yang, Shaohua Yang

"According to characteristics of Tm, Yb and Lu enriched oxides composition and problems in its traditional extraction separation process, the computer simulation of a optimized fuzzy extraction separation process, in which three products with high purity(>99.99%) could be obtained at same time, was carried out. Distributing Curves of every element in both organic and aqueous phases were worked out. Distribution rules of rare earth elements in every stage of the optimized extraction process were studied. The computation results of economical and technical index showed the consumption of the acid and base chemical reagents in the optimized process would be saved more than 30%.IntroductionFor the solvent extraction separation process of rare earths, countercurrent extraction process was widespread in the industrial practice. Normally, rare earth ions were extracted by the saponificated extractant and transferred into the organic phase, where the acidic extractant was saponificated by the base firstly. Then, the loaded rare earth ions were stripped from the organic phase into the aqueous phase by the acid. Therefore, the acid and the base were the main consumptions in the process, and the equilibrium acid of the stripped rare earth solution was one of the main pollution resources. Meanwhile, for the heavy rare earths, such as Tm, Yb and Lu, stripping was more difficult, and the equilibrium acidity of the stripped rare earth solution was higher, so the acid consumption increased greatly."

Jan 1, 2012

By J. W. Holzenthaler

Teams continue to play a major role at the Phelps Dodge Mining Company El Paso Operations, especially during the present time of low copper prices. The El Paso Operations' teams have taken the initiative during this copper market downturn and have helped reduce operating costs significantly. Because of this, Phelps Dodge El Paso Operations has continued to grow within the team process by creating a total, non- exempt salaried workforce. In the last year alone, the El Paso Operations have implemented three major initiatives to accommodate the team process. The first was the creation of "guiding principles", a policies and procedures handbook. Second was the "zero and beyond" safety initiative. Third was team compensation. In addition, the Copper Products Company has now adopted a work-team environment, following the lead of the refinery.

Jan 1, 1999

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 Christian Hecker

An Eh-pH electrochemical sensor developed for on-line pH and redox potentials copper sulphide flotation process control was studied. The electrochemical sensor cell includes two metallic platinum electrodes, a metallic antimony electrode and a high impedance reference cell which are polarized with a potentiostat. For pH and redox potential determinations, the Sb and platinum electrode potentials are measured, respectively, against the polarized electrochemical reference system. The behaviour of this electrode configuration has been investigated in a laboratory scale. An electrochemical sensor device has been succesfully installed and checked in El Teninte Colon Concentrator's SAG line feeding the copper flotation rougher circuit.

Jan 1, 1999

By John L. Uhrie

Oxide stockpile leaching operations can realize increased copper recovery and decreased acid consumption from in-situ generated acid resulting from the oxidation of intentionally introduced pyrite recovered from mill tailings or other sources. While all oxide leach ores can benefit from pyrite addition, low acid consuming ores can show remarkably increased recovery and net acid generation; however, more highly acid consuming ores will show benefit more exclusively through increased copper recovery. Additional work shows that the value of highly acid consuming ores can be optimized by balancing copper recovery against acid consumption.

Jan 1, 1999

By A. Bruynesteyn

It is well known that most North American gold deposits are of a hydrothermal origin and therefore they are often associated with sulphide minerals such as pyrite and arsenopyrite. When the precious metals in such ores are held captive inside sulphide crystals, the ores are called refractory because they do not respond to treatment by direct cyanidation. In these cases, it is necessary to recover the contained precious metals using high temperature treatments such as smelting or roasting, or high pressure leaching processes to break down the sulphide crystal matrices and thus liberate the precious metals for subsequent extraction by cyanidation. Sulphidic gold ores containing arsenic and/or antimony are considerably more difficult to treat because, in addition to their refractory nature, the arsenic and antimony content also prohibits treatment by direct cyanidation or amalgamation. These ores must be milled and their sulphidic gold values concentrated by flotation. The resultant concentrates must then be roasted to break down the sulphides before cyanide treatment can be applied.

Jan 1, 1985

By V. Panchanathan

The rapidly solidified Nd-Fe-B powders form the entire basis of the bonded magnet industry At present the rapid solidification is carried out exclusively by melt spinning, producing flake like particles having highly stable and magnetically hard microstructure These particles are comminuted into powder before being processed into bonded magnets These powders are magnetically isotropic having coercivities from 4 to 16 kOe The other type of powder recently introduced for bonded magnets is the anisotropic powder made by the hydrogen decomposition desorption recombination (HDDR) process. The characteristics and application of these isotropic and anisotropic powders are discussed.

Jan 1, 1997

By Henry Freiser

For the last several years, a systematic investigation of the equilibrium extraction behavior of selective tervalent lanthanides with representative chelating extractions of a variety of chelating agent families has been undertaken for the purpose of learning how to obtain chelating extractants of improved selectivity for separating individual lanthanide ions. The equilibrium extraction data (expressed as log Kex) for each reagent system are linearly related to the reciprocal ionic radius of the tervalent lanthanide ions. The role of adduct formation, steric hindrance, as well as the nature of the bonding atom in the chelate ring, represent some of the factors affecting selectivity arising out of our database of over 200 individual extraction systems, which will be discussed.

Jan 1, 1989

By David B. George

In spite of the many well-known problems inherent in Pierce-Smith converting, it remains the dominant copper converting process. Continuous copper converting and direct concentrate to blister smelting have been commercially available for over 25 years and now produce approximately 15% of copper smelter production. The two fully commercialized continuous converting processes, Mitsubishi MI Process and Kennecott-Outokumpu Flash Converting, and several emerging converting processes are reviewed with view of their potential, limitations, and environmental performance. Some myths regarding these technologies and Peirce-Smith converting are also challenged.

Jan 1, 2002

By J. H. Lee

LG Metals Corporation started its second smelter operation at Onsan along with the existing flash smelter on January 31, 1998. Onsan smelter has been producing about 140,000 tons of copper annually from concentrates with the flash smelting line since 1979. In accordance with an increase in domestic copper demand, LG Metals Corporation decided to expand smelting and refining capacity by introducing a second smelter line using the Mitsubishi continuous process and a new tankhouse in 1995. After two years' expansion works consisting of engineering, procurement, construction and a successful commissioning test, the total smelting capacity of Onsan smelter increased to 340,000 ton of copper annually from concentrates. This paper describes the smelting facilities, operation result, problems encountered and improvements during the start-up and early operation of Onsan's new smelter

Jan 1, 1999

By John D. Kinton

A patent is a right granted by the government to exclude others from making, using, selling, offering to sell, or importing a claimed invention. Once the right is granted, the patentee may use the U.S. Federal Courts to enforce that right. Reading a patent from a litigation perspective is quite different than reading it from a technical perspective. The Judge's interpretation of the claims will affect their scope, and likely the ultimate outcome of a patent case. Additionally, the patent right can be challenged. If done successfully, the patent can be rendered invalid or unenforceable. The likelihood of success, and well as the achievement of other litigation goals is often influenced by the forum where the litigation is initiated. Finally, patent litigation costs are significant, and will weigh heavily in the decision to file (or fight) a patent lawsuit.

Jan 1, 2006