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By B. Fresz

Before aluminum is utilized in automotive bodies, the longevity of the electrodes employed in the resistance spot welding of aluminum must increase. This paper explores the affects of electrode composition on electrode life. To compare these variables, electrode tests were completed on a Taylor Wield welding machine using, Cu-Cr, Cu- Zr, Cu-Cr-Zr, Cu-Be, and Glidcop electrodes tested to 12.5%, 25%, 50%, 100%, and 150% lifetimes. Electrode diameters were found via a magnification technique using a PULNIM video camera attached to a low magnification Wild Heerbrugg stereo-zoom microscope. From these measurements, graphs of electrode life verses face diameter and weld number verses face diameter were created. Analyses of these graphs suggest that a single failure mechanism is responsible for electrode failure, though the number of welds until failure (100% electrode life) varied with composition (700-2000 welds).

Jan 1, 1999

By A. N. Lasseigne

Hydrogenation behavior of the NaAlH4 intermetallics is investigated utilizing thermoelectric power and magnetic analyses. Using both thermoelectric power and magnetic susceptibility measurements on these intermetallics allows for confirmation and further insight into hydrogen's role in altering the material's electronic structure. The electronic and magnetic property correlations will indicate the direction for further alloy development to optimize hydrogen storage.

Jan 1, 2006

By M. Arenas

A corrosion study of a bonded NdFeB permanent magnet materials alloyed with titanium carbide additions has been undertaken. The materials were produced by rapid solidification by melt spinning. Commercial epoxy was used as a bonding medium. The corrosion results were compared with those of a near stoichometric unalloyed NdFeB. Anodic polarization and potentiostatic techniques in 0.9 M Na2SO4 solutions were used to characterize corrosion behavior. It was found that the addition of 6 a10 Tic resulted in superior corrosion resistance, as indicated by lower corrosion currents and less iron dissolution at fixed potential.

Jan 1, 1997

By M. C. Nielson

The paper describes the design and operation of pulsed columns as replacements for conventional mixer/settlers. The advantages, which the columns offer, include a reduction in real estate for the plant, elimination of diluent evaporation, containment of noxious vapors and reduced crud formation. In addition to the description of operation, the paper presents the findings of laboratory tests of pulsed columns extracting copper from pregnant leach solutions and also delineates potential advantages of the pulsed column in copper solvent extraction.

Jan 1, 1999

By J. A. Sanhueza

The environmental regulations and terms issued by the Chilean Government for all copper concentrate smelters have been a very important reason for permitting project developments that drastically decrease the sulfur emissions due to the pirometallurgycal copper process. A remarkable case of the Hernan Videla Lira Copper smelter, located on the Copiapó Valley and very near some housing-sets of a city of high development, are described. Results of this project's implementation of the control and reduction of off gas emissions, the control and monitoring system, the community conflicts, and the strategy to comply with the demands established by the state environmental institutions, are presented.

Jan 1, 1999

By Frank R. A. Jorgensen

Flash smelting is used to smelt a large proportion of the world's copper and nickel and some lead/zinc concentrates. Understanding the factors controlling the ignition of these concentrates is an important consideration in designing burners and maximising the throughput of the flash smelting process. The literature on the subject is briefly reviewed and techniques for the measurement of ignition temperature discussed. The mineralogy of the concentrates and the role of thermodynamics and phase diagrams in interpreting and predicting ignition behaviour are emphasised and applied to interpreting results obtained on a nickel concentrate.

Jan 1, 2002

By Stephan Mulch, Christian His, Patrick M. Stephan, Thibault Champion

"When fuel costs increase dramatically, waste to energy (WTE) conversion technologies become a good alternative to produce energy. The potential energy available in domestic wastes, in developed countries, could be upwards of 4% of their total energy needs. Due to low energy recovery and low level of treated domestic wastes in many countries, the energy coming from waste is generally less than 0.5% of the country needs.Domestic waste incineration can convert heat to electricity for industry and housing and allow waste volume reduction in countries where land fills are a scarce resource.There is a request to improve existing combustion technology by increasing energy recovery with better heat transfer in the boiler and also by increasing lining durability with more resistant materials and technologies.The knowledge of corrosion phenomena and material performance allows Saint-Gobain Group to develop and propose high performance refractory lining solutions.IntroductionThe interest in alternative energy has been growing dramatically in the two last decades due to several combined factors, such as global energy demand, fuels prices evolution (e.g. crude oil, Figure 1) or environmental and geopolitics factors"

Jan 1, 2008

By B. S. Boyanov

The hydrometallurgical technology for zinc production in Bulgaria is characterized by the use of considerable quantities of imported zinc concentrates and several kinds of Bulgarian ones which are quite different in chemical, phase and granulometric compositions. In this connection, 7 sulfide zinc concentrates (Bulgarian and imported ones) were investigated by chemical analysis, DTA, TGA, X-ray diffraction analysis, sieve analysis. The accomplishment of optimal mixing of concentrates and providing stabile mix composition for a long period of time of roasting in fluid bed furnace is a task of primary importance in the technological process control in zinc hydrometallurgy. This can be achieved using mathematical optimization methods.

Jan 1, 2006

By E. M. Alcântara

This paper describes some aspects about the relationship between copper electrorefining addition reagents and the hydrogen in the cathode. The conditions of electrorefining were studied by factorial design methods. The advantages of this technique are reduction in the number of tests, well organized experiments; improvement in productivity and reliability of results. The dosage of the two main addition agents, glue and thiourea, were varied simultaneously and compared with the hydrogen content in the cathode. The influence of these factors, as well their interactions were analyzed by statistical methods denominated ANOVA (Analysis of Variance). The increase of thiourea quantities, within of levels studied, influenced significantly at 95% confidence in the hydrogen content in copper cathode.

Jan 1, 1999

By He De-wen

The increasing population and living standard in urban areas, have been accompanied with the growing quantity and composition complexity of rubbish, which are causing well-known social effects of pollution, while rubbish (solid waste) is a recyclable resource. To convert rubbish into useful materials, the essential measure is to carry out sorted collection of rubbish. The preconditions of implementing sorted collection are presented in the paper. 1 Characteristics of rubbish composition and amounts of recyclable contents are basic condition to implement sorted collection. 2 The existing available technologies of recycling, economic benefit from recycling, and disposal scheme of residual rubbish are restrained condition for sorted collection. 3 Public understanding and support to sorted collection are the key to success. 4 The government policies to be favorable for sorted collection is the pledge of success. 5 The establishment of a steady solid waste recycling market is also a guarantee to implement sorted collection continuously. 6 To establish management system of rubbish recycling as soon as possible. Further, the methods and procedure of sorted collection are discussed in detail and beneficial comments and theoretical basis to promote sorted collection of rubbish in urban area are presented; it will contribute reference value to municipal solid waste management.

Jan 1, 2006

By Takayuki Ichikawa

Hydrogen storage properties of ballmilled mixtures composed of the hydrogenated nano-structured carbon (CnanoHx) and lithium hydride (LiH) were examined by thermal and optical spectroscopic analyses. LiH needs higher temperature than 600°C for hydrogen desorption even under vacuum condition, while CnanoHx, which was mechanochemically synthesized from graphite powder by ballmilling under hydrogen atmosphere, reveals hydrogen and hydrocarbons desorption in wide temperature range from 300 to 800°C. Nevertheless, the composite of CnanoHxand LiH prepared by ballmilling desorbs hydrogen in relatively lower temperature range from 150 to 450°C. These phenomena indicate that the thermally liberated hydrocarbon radicals immediately react with LiH and release hydrogen instead of hydrocarbons emission, because CnanoHx contains hydrocarbon groups at the edge of nano-meter sized graphenes, which are recognized as IR active C-H stretching mode, and LiH is well-known as an ionic crystal. Furthermore, it is of interest that a nanostructural feature persists in this composite even after annealing at 350°C, which shows excellent cycle properties as hydrogen storage media.

Jan 1, 2006

By P. Stantke

In recent years the CollaMat process has been used successfully worldwide in a number of copper electrorefining tankhouses as an instrument for measuring the glue concentration and optimizing cathode quality. Owing to its measuring principles the CollaMat can be used not just for measuring the concentration of active glue but also the activity of other substances, which have an impact similar to glue on the copper deposition. In SX-EW plants guar is frequently used instead of glue as a levelling additive. In our laboratory the effect (activity) and the decomposition rate of guar in copper electrolyte was examined. As expected, the results show that guar has an effect similar to glue on the copper deposition. However, at the same temperature, a greater quantity of guar is required to achieve the same results. As with glue, the decomposition rate (due to hydrolysis) of guar is strongly dependent on the temperature. Therefore, in practice, its on-line monitoring is necessary to guarantee the same guar activity at any time.

Jan 1, 1999

By Melissa L. Trapani

The removal of molten products from metallurgical furnaces is one of the most hazardous and labour intensive processes in a non-ferrous smelter. The proximity of operators to the molten metal and slag during tapping and the oxygen lancing that facilitates the flow have led to many reported injuries on tapping floors. In most cases, tapholes are opened and closed periodically leading to extreme thermal cycling in the tapping assembly. As a consequence, refractory wear rates are high and unpredictable in the taphole. This paper provides a review of the current state of taphole development, and gives a methodology that is now being applied to gain a better understanding of the taphole region to allow design improvements.

Jan 1, 2002

By V. M. Paretsky

Most recent developments made in the Gintsvetmet Institute in the field of technologies and equipment for single-stage autogenous smelting of copper sulfide raw materials to produce white metal and blister copper on the basis of oxygen-flame smelting process and separation of highly basic calcium-containing slags have been discussed. This technology includes the oxygen-flame smelting process (KFP Process) to produce highly basic self-disintegrating ferrite-calcium slags with their subsequent flotation to recover copper and a basically new sparging smelting process (FBP Process) to produce combined slags subjected to decopperizing inside the same furnace. Results of special investigations of the slag structure obtained in the KFP and FBP processes and substantiating selection of their chemical and phase composition have been presented. It has been demonstrated that the above processes meet the stringent world-level requirements to advanced technologies with respect to energy conservation and environmental safety with different scales of production and within a wide range of specific conditions of particular operations.

Jan 1, 2006

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 D. G. Schmidt

Tests were conducted on C86200 high-strength yellow brass in order to ascertain the effect of a low level of nickel on the mechanical properties on this alloy. A series of two alloys was studied, one of which had a nickel content of 0.85% and the other with <0.05% nickel. Copper and aluminum content ranged from 62.5% to 64% and 3.2% to 4.6%, respectively. When compared by zinc equivalents, a nickel addition of 0.75% in high-strength yellow brass does not act like copper but raises the tensile strength, 0.5% yield strength and BHN while lowering the elongation.

Jan 1, 1999

By Karl A. Gschneidner

Magnetic refrigeration was first used in the mid-1920&apos;s and new developments seem to have taken place about every 20 years, and this is especially true for the mid-1990&apos;s. The active magnetic regenerator magnetic refrigerator has the promise to become the first practical machine utilizing the magnetocaloric effect for cooling (and also heating). The basic principles are briefly discussed. Since the temperature lift for the magnetocaloric effect spans about 50 K, one will need to utilize several ferromagnets with different magnetic ordering temperatures in order to reach temperatures below ~250 K. The basic properties, behaviors, limitations, and new phenomena and knowledge are discussed.

Jan 1, 1997

By T. Taniguchi

The existing Mitsubishi Process line at Naoshima Smelter and Refinery has been operating successfully since 1991, and its present production capacity is 270,000tpy of copper. Furnace relining works have been carried out every two years to coincide with the compulsory bi-yearly boiler inspection, but the next target is to extend the furnace refractory life to four years, while still undergoing the mandatory boiler inspection every two years. Although the damage of hearth bricks beneath lances in the Smelting furnace was a matter of concern, it was reduced by controlling gas velocity and evening solid distribution to each lance. The life of bath level bricks in the Converting furnace was also a concern, but four-years continuous use of the bricks was achieved in the course of the last two campaigns. Several other improvements were also carried out to the cooling systems during the shutdown in 2005 to ensure longer campaign life. This paper summarizes recent improvements implemented to enhance the advantages of the Mitsubishi Process.

Jan 1, 2006

By Michael J. Virnig

The formation of crud is a normal part of operating a solvent extraction circuit for the recovery of copper. It periodically must be removed from the circuit. This results in significant costs in terms of manpower, downtime, and loss of circuit organic. Field studies have been carried out that show that the presence of a thermodynamic modifier in the organic phase contributes to crud formation. In an effort to better understand what factors contribute to crud formation, laboratory studies involving competitive adsorption studies with model solids have been carried out. The results of these laboratory studies will be integrated with the results of the field studies to present a better understanding of crud formation.

Jan 1, 1999

By Vânia L. L. Andrade

Igarapé Bahia Mine is located in Carajás area, northern Brazil. Currently Companhia Vale do Rio Doce operates there a CIP / heap leaching plant treating an oxide gold ore containing about 4 g Au /t and 0,2% Cu, which produces 11 t of gold per year. Recent geological survey has identified a signifcant copper-gold reserve underneath the oxide gold ore. The processing aspects of this copper-gold sulphide ore are described in this paper. It includes ore characterization studies, grinding and flotation tests, orebody variability assessment, flowsheet selection and preliminary economical evaluation Emphasis is given to studies aimed at depressing fluorine bearing minerals to achieve a clean and marketable flotation concentrate.

Jan 1, 1999