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By Roberto Parra, Roberto Parada

"A novel process for minor elements control in copper pyrometallurgical production is proposed based on a theoretical analysis and the results of an experimental program. Its application can solves operational problems related to volatile elements that determine pollutants gas emissions and the final quality of anodes. The process considers a calcination of mixtures of the dust with sulfidizing agents such as dirty copper concentrate or elemental sulfur at temperature under 800 °C. The product are a clean calcine that recovers all the Cu content on the dust and a gas stream that collect the minor elements as sulfides species. The calcine can be returned to the smelter avoiding the As increasing in the circuit and so on, the capacity for the treatment of dirty concentrates for the smelter can be higher. The possibility to apply vacuum in the calcinations step can decrease the operation temperature. The solid condensed from the gas has different options for its stabilization, with the advantage that this stream represents few mass with high As content.IntroductionThe control of undesired minor elements (IVIES) in conventional pyrometallurgical copper production is especially relevant for ore deposits associated to Andes region. The concentrates that are being produced present every time higher levels of volatiles and harmful elements: group Va (As, Sb and Bi), Pb, Zn, and Sn."

Jan 1, 2008

By Yoshio Waseda

A laser flash method has been applied to obtain the thermal diffusivity values of Zr55Al10Ni5Cu30 alloy in the liquid, glassy, crystallized and supercooled liquid states. The electrical resistivity of this particular alloy was measured in the glassy, and crystallized states by a direct current four probe technique. A specific heat of Zr55Al10Ni5Cu30 alloy was also determined by a differential scanning calorimeter in the glassy state. On the other hand, thermal diffusivity values for two alloys of Zr60Al15Ni25 and Zr65Al7.5Cu27.5 were measured in the crystallized and liquid states. The thermal diffusivity values of three Zr-based alloys in the liquid state are summarized in the linear equations with positive temperature dependency and it is noted that the lower the thermal diffusivity values of Zr-based alloys at liquidus temperature, the lower the critical cooling rate to obtain metallic glass phase becomes. The thermal diffusivity values of Zr-based alloys were compared with those of Pd-based alloy case. These results suggest that thermal diffusivity of alloy liquids might be an indicator of the glass-forming ability of Zr-based and Pd-based alloys.

Jan 1, 2006

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 Leijun Li, M. M. Mahapatra

"A three-dimensional finite element model with moving heat source was developed for pulsed-laser powder deposition (PLPD) process. Experiments were conducted to study the repair of superalloy components using the PLPD process. During the experiments, IN 625 powder was deposited on a superalloy substrate similar to IN 738. The process was modeled using three-dimensional finite element analysis. Element birth and death technique was used in the finite element model for simulating the deposition of powder layer on the substrate. A moving distributed heat source was used in the thermal model for realistic simulation of the process. Temperature dependent thermal material properties including enthalpy were used for the powder and the substrate in the transient thermal analyses. The fusion zones and peak temperature distributions of the deposits were predicted from the transient thermal analyses.IntroductionPoor weldability is a critical issue of superalloy repairing. The microstructural directionality of the superalloy components are disrupted when repaired by the fusion welding processes. Currently there is no widely accepted method to economically and reliably repair directionally solidified superalloys components. Pulsed laser powder deposition process (PLPD) is a promising repairing technique as the substrate is not severely affected by the heat source.In this study PLPD technology is used as the tool for superalloy repairing. In most of the land based turbine engines the directionally solidified nickel based superalloy similar to IN 738 [1] is used as the bucket material. The turbine engine blade tips are subjected to a combination of extreme operating conditions and corrosive environment. The tip of the nickel based turbine engine blades can be repaired using IN 625 material as suggested in the literature [1-2]. IN 625 is considered to be ductile and strong enough for the purpose of Ni based turbine engine blade tip repair[1-2]. During the present PLPD investigation, IN 625 powder was used as the deposit material on an experimental super alloy substrate similar to IN 738 superalloy used as the cast superalloy for the turbine engine blades."

Jan 1, 2012

By Gerardo R. F. Alvear, Alistair S. Burrows, Stanko Nikolic, James S. Edwards

"The copper ISASMELT™ process has evolved over more than a quarter of a century and can now be considered mainstream, with single furnaces producing more than 340,000 tpa of copper in matte. The next evolutionary step for the ISASMELT™ technology is to directly challenge the dominance of the Peirce-Smith converter by the implementation of a continuous copper converting process on a commercial scale. The present work describes the status of the continuous converting process – ISACONVERT™.Continuous converting has been performed successfully in pilot scale ISACONVERT™ plants, where operating results have verified the predictions of fundamental research and reinforced the underlying confidence in the design parameters. From a matte feed rate of 250 kg/hr, a calcium ferrite slag and a low-sulfur blister have been produced. Design is now complete for the first commercial application of the ISACONVERT™ process. The present paper describes the status of ISACONVERT™ by summarising results of recent pilot plant tests and describing the first commercial plant design."

Jan 1, 2009

By A. Elizabet Serna

The weak acid is a by product obtained in a pre-treatment of gases from a copper smelter prior to sulfuric acid manufacture and the main components of this weak acid are: sulfuric acid. copper, arsenic. antimony, bismuth and iron. Usually, this effluent is neutralized with lime and the solid residues are stored in a landfill as a hazardous waste. This work was directed at determining the optimal conditions to recover copper from weak acid using a cementation process before the neutralization of the effluent. The variables investigated are: Effluent temperature, iron scrap amount and acid concentration versus reaction time. The results of these experiments show that the cementation process of copper and the co-cementation of impurities such as arsenic, antimony and bismuth were in accord with the theory of the electrode potentials.

Jan 1, 1996

By J. P. Downey, T. Salisbury, M. Berlin, E. Rosenberg, G. Pinson, R. Christianson, K. Gleason, W. Gleason, S. Davis

"The Center for Advanced Mineral and Metallurgical Processing is developing membrane production technology based on autocatalytic reduction of palladium from solution onto a unique, porous substrate. Surface membranes and catalytic structures are critically important to applications that range from hydrogen purification membranes to petroleum refining. Autocatalytic reduction processes represent a cost effective method of producing stable surface layered structures that have good working lives. These attributes are particularly important in the production of palladium alloy purification membranes used in hydrogen production. Although considerable research has investigated the interaction of hydrogen and palladium alloys, the mechanisms in play while the membranes form are not well understood. Preliminary research has identified three distinct deposition mechanisms and it appears that substantial control over the resulting membrane is possible.IntroductionPalladium-based membranes separate hydrogen from other gases because hydrogen is uniquely soluble in and readily passes through bulk palladium. As currently produced, palladium-based membranes are expensive and have short service lives. These circumstances are due in part to the lack of a complete understanding of palladium or palladium alloy deposition. The Center for Advanced Mineral and Metallurgical Processes (CAMP), in collaboration with the Metallurgical and Materials Engineering Department at Montana Tech and the Chemistry Department at the University of Montana, is engaged in the development of new methods and materials for hydrogen purification membrane production.In membrane production, the palladium requirement depends on substrate surface properties such as surface chemistry, porosity, and roughness. Thin, defect-free membranes have been successfully produced on substrates of porous glass, alumina, and stainless steel. However, the differences in the thermal expansion coefficients of palladium membranes and porous glass or alumina substrates cause problems at operating temperatures. The use of stainless steel substrates is advantageous because stainless steels have thermal expansion coefficients similar to that of palladium and they are stable at the required operating temperatures (Wicke, E., Brodowsky, H. and Ziichner, H. ). Stainless steel is also readily available and relatively inexpensive."

Jan 1, 2012

By J. M. Tourre

1995 have seen a continuation of a positive trend in the Rare Earth industry The availability of a greater diversity of Raw Material has brought additional flexibility to the Producers permitting better economics China remains the major raw material source; Chinese concentrate producers have increased capacity in 1995 (Baotou, Sichuan, etc) China's role in the Rare Earth industry will continue to evolve; the acquisition of a majority equity position by San Huan/CNNC will have a significant impact on both the Rare Earth and Magnet markets Chinese producers are increasing the quality of their products and realize their true values Chinese market, itself, is also changing as the internal needs for separated rare earth's grow Already already producer of Lamps, Loudspeakers, Magnets, and TV tubes, China is in an unique position where the potential of its internal market might be more promising than the prospects outside China 1995 has also seen the application market become more diverse and complex. There are new applications growing at a very strong pace (such as battery alloy), applications that are now penetrating their target markets with significantly increased growth rates (such as bonded NdFeB), and some applications that became more complex requiring much more sophisticated products (such as catalysis). Rare Earth producers have to spend significant ressources in order to monitor the market trends in order to predict the demand and then adjust their raw material mix. Even though there is a greater diversity of raw material available, there is still some Rare Earth elements that are in excess, while other are just in balance. As a consequence rare earth producers invest heavily in R&D in order to develop new applications for these excess elements.

Jan 1, 1997

Lance based copper-nickel matte converters have become an established technology in the field of base metal sulphide smelting and converting. An Ausmmelt® converter is currently being constructed at Anglo Platinum in South Africa to convert a nickel-copper rich matte containing platinum group metals (PGM's). The accurate prediction of the matte chemistry is required to control the composition at the endpoint which influences segregation of PGM's during the subsequent slow cooling and magnetic separation processes. A hybrid modelling approach is introduced in this paper that incorporates both the effect of thermochemistry and system dynamics. It will be shown how the model relates to fundamental conservation laws, while still providing enough flexibility to adapt to changing operating conditions. It will also show how off-line modelling can be incorporated into a robust on-line model. Based on the data from many pilot plant trials, the model prediction performance is shown to be within the accuracy requirement set by industry and therefore constitutes a reliable basis for model based control. The final generic model structure takes on the form of an thermodynamically integrated ARMAX hybrid model. The final model has the advantages of being dynamic, adaptive, robust and it can be related to thermochemical fundamentals.

Jan 1, 2002

By Hartmut Rossel

VAW aluminium AG has built a "Recycling-Technikum" (Recycling Research Centre) to add a new arm to the company's Corporate Research and Development Department. The Recycling Research Centre, a pilot plant for scientific research, has been in operation since September 1993. These state-of-the-art facilities allow the investigation and optimisation of recycling techniques in 'a global way and in detail. Research is concentrated on the unit operations - processing, melting and waste-gas purification - with the available installations making it possible to compare different alternative process combinations on a 100-kg scale. One of the main targets of VAW research is the development of recycling techniques for packaging. The paper presents an approach to recover the aluminium contained in flexible packaging materials using an integrated melting and waste-gas purification system.

Jan 1, 1995

By Alex Moyano

Due to very demanding environmental rules, and to the incrementing impurities contents in the processed concentrates, Codelco Norte smelter permanently faces new demands for planning the production program with the present fulfillment of the environmental regulation. Accordingly, the CN smelter along with IM2, developed an impurity distribution simulation model, M-DICE, which predicts the impurities behavior for each of the process units of the smelter under different process configurations and concentrates quality. The development of the M-DICE included the gathering of operational data for the process units of the CN smelter, including temperature, oxygen enriched air, matte grade, etc. Then based on a mass balance for each of the process units involved in the smelter a thermodynamic evaluation was done to derive the arsenic fractional distribution among the condensed (matte/white metal/copper/slag) and gas phases. Then, the validated M-DICE was able to predict the arsenic behavior in the Teniente converter processing complex concentrates with high arsenic content, among others. At present, M-DICE is in its last stage of development, and is expected to be a suitable environmental and process management?s tool for the Codelco-Chile?s smelters.

Jan 1, 2006

By Chuan-fu Zhang

In present work, the physical properties of molten FenO-MgO-CaO-SiO2 slags were measured .It is shown by the results that when the slag composition is as follow: MgO 8%~12%, CaO 2%~8%, Fe/SiO2 1.2~1.6, the viscosity of the slags decreases with the increase of temperature. When the Fe/SiO2ratio and the MgO content are fixed, the electrical conductivity increases and the viscosity decreases as CaO content increasing, while the content of CaO exceeds 6% its influence weakens. When the MgO content is 11% and the CaO is 6%, the viscosity of the slag decreases markedly as the increase of Fe/SiO2 ratio. Its influence to viscosity is inconspicuous when the Fe/SiO2 ratio exceeds 1.5. When the CaO content is 6% and Fe/SiO2 is 1.2, the electrical conductivity decreases with the increase of MgO content as temperature is below 1290, but increases when temperature is above 1290. When the MgO content is 11% and the Fe/SiO2 ratio is 1.2, the electrical conductivity increases with the increase of CaO content. When the CaO content is 6% and MgO content is 11%, the electrical conductivity increases as the increase of Fe/SiO2 ratio, while its influence weakens as the temperature increases continuously. The electrical conductivity rises when temperature increases at any slag content. The melting temperatures of FenO-MgO-CaO-SiO2 semi- synthesis slags from this work were below 1290.

Jan 1, 2006

By Dhanesh Chandra

In this symposium, research in the area of energy conversion is presented. This symposium has special significance, as we honor three prominent scientists from hydrogen storage research and development field. In this symposium, the majority of papers presented by international scientists and engineers are in the area of hydrogen storage. Other energy conversion papers include magnetic materials, superconductors, and thermal energy storage materials. Recent developments in light-weight high gravimetric hydrogen density hydrides have led to potential use of hydrides for onboard automobile and other applications. This, of course, is significant from environmental concerns of CO2 and other emissions from the current use of carbon based fuels in automobiles. Thus, it is becoming increasingly important to switch to cleaner alternative fuels such as hydrogen [1]. The Challenge of Vehicular Hydrogen Storage as potential hydrogen energy carriers for vehicular applications, with a driving range of approximately 300 miles, require ~5-13 kg of hydrogen stored on-board. In the United States, Centers of Excellence have been established in metal hydrides, chemical hydrides, and carbon-based materials, and abundant scientific and industrial research is being carried on metal hydrides; only some of the current research from the Centers will be reported here. The European commission, Japan Institutions, and others also have numerous hydrogen storage programs in progress. Several international collaborations have also begun between IEA and IPHE scientists to accelerate the progress of development of practical hydrides. A summary of the abstracts is included in this overview.

Jan 1, 2006

By Gil Bourcier

A process has been developed for detoxifying spent potliner (SPL) in which the SPL is blended with limestone and an anti-agglomeration agent and thermally treated in a rotary kiln. The process has been proven and a commercial plant is in operation at Gum Springs, Arkansas. The treated by-product material has been delisted by the U.S. EPA and is now a potential raw material for many commercial applications. Finding uses for a non-hazardous material has many advantages over finding uses for a hazardous material like SPL. Complete usage of the by-product will complete the life cycle and eliminate any landfilling of non-hazardous SPL by-products or residues. Being non-hazardous and containing compounds used in the ceramic and numerous other industries assures many potential uses for the spent potliner by-product.

Jan 1, 1994

By Charles Zimmerman

The Genesis gold mine, owned and operated by Newmont Gold Co., is located in section 31, T36N, R50E within Eureka County, Nevada along the Carlin Trend of sediment-hosted disseminated gold deposits. Mining commenced in 1986 with present mineable and stockpiled reserves listed at 17,711,000 tons of ore averaging 0.073 opt Au, totalling 1.292 million ounces of gold. Ore is primarily hosted within Devonian calcareous siltstones that have been subjected to intensive argillization and silicification episodes. Additional mineralogic and geochemical features of the Genesis ores include enrichment in iron-oxides, kaolinite, arsenic and antimony; the ore zone is relatively depleted in carbonates and sulfides as a result of supergene and hypogene oxidation. Two major structural zones enhanced the permeability of the siltstones and served as the main hydrothermal conduits within the deposit. Prior to the main ore stage, the host rocks were subjected to metasomatic effects caused by emplacement of the Juro-Cretaceous Goldstrike granodiorite pluton and associated dikes and sills. Micron-size gold occurs in clays, micro-crystalline quartz, and in arsenical complexes. Non-oxidized carbonaceous and sulfidic ores and silica-locked ores result in variable preg-robbing and refractory responses during cyanide recovery. Selective mining and milling has resulted in the successful treatment of the Genesis orebody.

Jan 1, 1988

By Shunichi Ajima

PT. Smelting Co. was established in February, 1996 to construct and operate the Gresik Smelter and Refinery. The construction work of first Copper Smelter and Refinery in Indonesia was completed in the end of August, 1998 and it was put into the integrated test operation in December, 1998. Gresik Smelter and Refinery is designed to produce 200,000 tpy of copper cathode from copper concentrate supplied from Grasberg Mine of PT. Freeport Indonesia Company in Irian Jaya, Indonesia. As by product 592,000 tpy of sulfuric acid, 382,000 tpy of slag, 31,000 tpy of gypsum and 480 tpy of slime will be produced in the full operation. Major processes applied at Gresik Smelter and Refinery are: Smelter: Mitsubishi Continuous Copper Smelting and Converting Process ( Mitsubishi Process ) Anode Casting: Continuous Casting of Copper Anodes with the Hazelett Twin Belt Caster Refinery: ISA Process Acid Plant: Lurgi Mitsubishi Double Contact Process

Jan 1, 1999

By R. E. Fanning

"IntroductionThe Aluminum industry is one of many materials industries which strive to make their material the preferred choice for large volume products. In some applications one material has a natural advantage over others, but more frequently several materials compete with one another, each providing one or more advantages and some trade-offs. Customers may design their product with several objectives such as minimum system cost, maximum customer appeal or maximum manufacturing flexibility, choosing materials which best combine cost and performance. In such markets it may become necessary for a material supplier to enhance the attractive features of the particular material to outweigh its disadvantages.It is difficult, if not impossible, to predict how various materials will evolve. Technological breakthrough, government regulations, material availability or sociological issues may redefine the balance between competing materials. In spite of some uncertainty regarding the competitive position of competing materials, there is little doubt that unrelenting pursuit of product quality improvement and cost reduction are essential to future viability of the aluminum industry. It is the intent of this paper to identify some areas where technological improvement would be beneficial. Thus this paper is a collection of briefly described problems that will hopefully stimulate the thoughts and research required for knowledge based solutions. Rolling ProcessA particular example is the beverage can industry where aluminum, steel, glass and plastics vie for a share of the m.arket. The high cost of aluminum relative to steel or glass requires minimizing the amount of metal per can. The high intrinsic value of aluminum has led to extensive recycling of cans although net metal cost is still higher than that of the competing materials. Intensive engineering of the beverage can led to improved design and better understanding of material requirements. These improvements permitted substantial reduction in sheet thickness over the past decade. The downward trend in metal thickness for beverage can sheet is shown in Figure 1."

Jan 1, 1988

By A. G. Raraz

Reactive metal electrorefining presents a number of problems that pose obstacles to commercial operation. Cerium has been chosen as the surrogate for certain reactive metals because of its thermodynamic and electrochemical characteristics. A comparative review of the properties for cerium and plutonium has been presented to justify the choice of cerium as the surrogate metal for studying electrorefining. This review has addressed the electrochemical, thermodynamic, and kinetic parameters of molten salt electrorefining of cerium metal to provide an insight to this extremely important process. The cell components and configuration, current efficiency of the process, purity of the cathodically deposited metal and the power requirement of the system are evaluated for a molten CaCl2-MgCl2 salt electrolyte using a molten, stirred impure anode. Crucible designs, salt electrolyte, cell temperature and electrode materials are also evaluated. Selection of the salt electrolyte and the cell temperature have been suggested from this study.

Jan 1, 1992

By Ronald H. Church

Dewatering of mine waste slurries has been successfully accomplished by the proper use of polymers in flocculating the fine particulate matter suspended in the slurry streams. Conventional treatment of fine waste slurries usually involves some form of impoundment treatment or storage. These impoundments present unique environmental problems. When filled to capacity, the impoundments are usually unloaded with a dragline and transported to a separate disposal area. The U.S. Bureau of Mines has conducted dewatering studies utilizing polymer technology in combination with a mobile field test unit designed by the Bureau. The purpose of these studies was to determine if the fine waste slurry from the mining operation could be successfully dewatered. Results of the investigation have shown that the slurry can be dewatered successfully. The dewatered products obtained from the tests ranged from 45 to 50pct solids. This material continued to dewater, approaching 70 pct solids within 24 h, and could be easily handled using conventional transportation equipment including conveyor belts.

Jan 1, 1994

By Guo Chen, Jin Chen, Jinhui Peng

In this study, the influences of the green evaluation variables on the characterization of microwave shaft furnaces were systematically investigated. These variables include: resource consumption, environment impact, production cost, processing time and quality of microwave shaft furnaces. A greenness evaluation index, evaluation system and evaluation model of microwave shaft furnaces were established. The analytic hierarchy process and fuzzy comprehensive evaluation were applied to the evaluation process. Resource consumption and environment impact had a statistically significant effect on the green evaluation of microwave shaft furnaces. The results indicated that green evaluation techniques can be applied effectively and efficiently to the process manufacturing of microwave shaft furnaces.

Jan 1, 2015