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By I. C. Knight

The current levels of copper smelter by-product acid production are reviewed on a regional basis, together with the possible changes in the future. There will be increasing pressure for all smelters to achieve a sulphur capture level of at least 95% by the end of the decade.

Jan 1, 1996

By Hans Prem

There has been a dramatic development in the field of magnetic materials in the last 10 to 15 years. Capacity improvement of electronic components especially required an increased production of "rare earth magnets", e.g. samarium-cobalt (SmCo) magnets and neodymium-iron-boron (Nd-Fe-B) magnets. We participated in this development and learned how to construct systems for the dry processing of these magnet materials. In the meantime we have supplied a large number of these systems for coarse and fine milling. Processing is effected in a protective atmosphere in order to avoid oxidation and thus deterioration of the magnet materials.

Jan 1, 1992

By Mike Adams

Comprehensive pilot testwork has been conducted on BHP Billiton's Ravensthorpe nickel laterite deposit over a fifteen-month period at Lakefield Oretest. Some 228 tonnes of ore were processed in a beneficiation pilot-plant comprising scrubbing, attrition scrubbing, screening and thickening over sixteen pilot runs with an average mass closure of 99.2%. This produced a suitable feed for hydrometallurgical piloting over seven runs covering 1,680 hours of operation. The integrated EPAL® (enhanced pressure acid leach) circuit comprised a limonite pressure acid leach front end discharging into a saprolite atmospheric leach circuit and subsequently to induced jarosite precipitation, counter-current decantation, iron removal, mixed hydroxide precipitation, and manganese removal. The pilot plant met its key objectives in demonstrating the flowsheet's technical viability, and generating raw data inputs for the project feasibility study. Rapid, intensive data capture, collation and reporting helped solve key flowsheet issues. The pilot plant also demonstrated its value as a risk management tool in the resolution of numerous engineering, metallurgical and materials selection issues at a manageable scale. A disciplined approach to experimental planning, operation and management was a significant contributor to the overall success of the campaign. Keywords: Ravensthorpe, Nickel, Piloting, Beneficiation, Pressure, Leach

Jan 1, 2004

By L. N. Ertzeva

The process for thermal treatment of current pyrrhotite concentrate in reducing environment with the use of disperse metal iron as an iron-bearing additive (optimal volume 20-30%), with downstream magnetic separation of the calcine, has been studied. The reduction process has been performed in conditions emulating those of both tube and fluidize-bed furnaces.

Jan 1, 2006

By Toru Taniguchi

In the Mitsubishi smelting furnace, copper concentrate, silica sand and water granulated slag from the converting furnace are injected through the process lances, together with oxygen enriched air, into the melt. Because bath smelting is used, the rates of particles/melt and gas/melt reactions are high enough and therefore tine grinding of the solid materials is' not necessary. Among these reactions, the dissolution rate of silica sand is the slowest and limits the overall reactions in the smelting furnace. Information on the dissolution rate of silica sand plays an important role for design of a new furnace. Theoretical calculations of the dissolution rate .of silica particles have been reported elsewhere. The authors conducted cold model experiments and could verify the calculation. In this paper, the dependence of dissolution rates of particles on the gas blowing rate, particle size and solid penetration depth in the bath is discussed.

Jan 1, 2002

By Roald Ysteboe, Finn Olesen

"Elkem has developed a process that utilizes SPL as a raw material for pig iron production. This process will be demonstrated in industrial scale during 2008 and 2009. The process developed produce iron, and the reduction material used, is the carbon present in the SPL. The iron source could be either virgin iron ore or waste/recycled material from the steel industry. The SPLrefractory and bath material is dissolved in the slag produced. The slag is designed so that any leaching of environmentally dangerous elements is minimized. This process can in addition to SPL, consume other types of waste derived from the primary production of aluminium. Elkem intends to supply this demo project with SPL and other waste products from external sources, domestic as well as international ones.IntroductionSpent Pot Lining (SPL) is generated when an electrolytic cell for producing aluminium is taken out of service and the refractory and carbon lining is removed from the steel potshell.The yearly generation of SPL world wide is exceeding 500 000 tonnes. The major amount of this quantity is stockpiled or land filled, unprocessed.SPL contain large amount of water soluble fluorides and some amount of cyanides and is classified as hazardous waste in most countries."

Jan 1, 2008

By A. V. Tarasov

The insufficient scientific and technical level of a number of operations in the nonferrous metals industry encourages development of new processes and equipment, including smelting in liquid bath, flame-type sparged smelting unit for combined processes, electrothermal process with the use of alternating current (PDF furnace), electrothermal processing of complex raw materials and intermediate products at nonferrous metallurgical plants, etc. One of the most important aspects for development of new processes and equipment in the Gintsvetmet Institute is their environmental safety. Special attention is paid to environmental protection measures, which is also of important economic and social significance. This refers also to a complete extent to processing of reserves of man-made raw materials and wastes available at the existing operations with the use of innovative techniques ensuring not only resource conservation and environmental protection, but also abatement of negative impact on the nature due to accumulated industrial and domestic waste, reclamation of the land used for waste disposal and recycling of nonferrous metals. Technologies and equipment developed in the Gintsvetmet Institute and based on electrothermal processes determine the prospects for ensuring more integrated usage of ores and man-made raw materials.

Jan 1, 2006

By Robert Matusewicz

Ausmelt Technology has been applied to the recycling of spent pot liner (SPL) generated from primary alnminum production. The process is centered on the Ausmelt furnace, in which the SPL is converted under high temperature, oxidizing conditions to an HF containing gas stream and inert slag. fluorine is recovered from the SPL as HF gas and is concentrated and used to manufacture AIF) for recycle to the aluminum smelters. Approximately 87% of the fluorine can be recovered and converted to AIF), with the remainder being effectively tied up in the by product slag. Cost projections show that the recycling process will be competitive with other processes for SPL. The production and recycling of AIF) provides available credit that significantly offsets the operating cost of the facility. Ausmelt Technology for recycling of SPL is currently being marketed in North America by Ausmelt Technology Corporation in Denver, Colorado, and in the rest of the world by Ausmelt Limited of Dandenong, Australia.

Jan 1, 1996

By Robert D. Pehlke

"The evolution of oxygen steelmaking is reviewed and new operating processes are described. The developments which could impact this technology are summarized. Staged and continuous steelmaking are considered in the light of new technologies. The future opportunities for oxygen steelmaking processes are overviewed. IntroductionThe use of oxygen in steelmaking was originally brought on the scene by the development of pneumatic steelmaking. Sir Henry Bessemer in England originally conceptualized the use of gaseous oxygen in steelmaking, and then he and William Kelly in Eddyville, Kentucky independently developed the original pneumatic process which involved blowing air through a bath of molten pig iron to oxidize the carbon and silicon and produce steel. This process and many following processes, including those which would use pure oxygen gas, have been proposed.Beginning with the first commercial oxygen steelmaking vessels at Linz, Austria in 1952, the world steelmaking industry has adopted this style of processing. In general, the process has involved the use of steel scrap in amounts from 20 to 35% of the metallic charge with molten pig iron produced in blast furnaces making up the remainder. The impurities in the charge are oxidized through the use of oxygen gas injected into the steelmaking vessel.However, currently being adopted into commerical practice and on the horizon are a number of advances in this process which include the use of iron ores as a source of iron and oxygen, the use of an all scrap charge, incorporation of pre-reduced iron, the use of auxillary fuels to change the balance of cold and liquid iron-base charge materials and numerous refining techniques."

Jan 1, 1988

By V. Ramachandran

Under the Resource Conservation and Recovery ACT (RCRA), generators of listed or characteristic hazardous wastes must find satisfactory means for disposal. of wastes. Initially, for many this meant landfills and deep-well injection. Until recently, mining and metallurgical by-products have largely been exempt from RCRA, but now are coming under its jurisdiction. With the increasing closures of landfills, companies in the U.S. such as electroplaters, miners, metallurgical plants and others are turning to recycling as an alternative to treat their wastes. While the cost of recycling has been challenging, the long-term economics prove attractive because recycling interrupts the cradle- to-grave responsibility for the waste generator. The present paper describes the recycling of hazardous wastes at ENCYCLE/TEXAS. Encycle extracts marketable metals from metal-bearing sludges and wastewater using hydrometallurgical processes borrowed from the mining and metallurgical industry.

Jan 1, 1994

By Tracy T. Morris, Luis G. Navaro

"Anodic copper slimes produced during the electrolytic refining of copper are routinely batch leached to remove copper. At the Amarillo Copper Refinery, an atmospheric leaching process was converted to an autoclave pressure leaching system to improve the removal of copper, reduce the consumption of oxygen, improve leaching times and enhance tellurium recovery. The benefits of pressurized versus atmospheric leaching of slimes were soon realized by obtaining the desired level of decopperization in a shorter time and with lesser quantities of reagents. The autoclave was designed and constructed with a unique oxygen injection system that enables good control of the leaching process and with no plug-ups. Other features include a mass measuring system that balances the quantity of slimes to be leached to the desired final solution concentration based on initial feed concentrations. The end result was a more efficient and controllable leaching process for removing copper from anode slimes.IntroductionThe electrolytic refining of copper consists of an electrolytic cell filled with a sulfiiric acid based electrolyte and pairs of copper anodes and cathodes. When a current is applied, copper in the anode dissolves and is plated onto the cathode. Impurities within the anode that are more noble than copper do not dissolve and end up at the bottom of the cell and are referred to as slimes. Gold and silver are the main slimes constituents of interest because of their monetary value, but there typically are significant quantities of selenium, tellurium, lead, antimony, arsenic, bismuth, nickel, silica and tin. Copper is also present, usually as a metallic or as a reactant with tellurium, selenium, oxygen or sulfur and can range from 10 to 30% of the slimes fall."

Jan 1, 2012

By K. Asokan, K. Subramanian

"Electrowinning of copper by monopolar cells require common anode and cathode busbar and crossbars to connect each electrode to the respective common busbar. On the other hand, the bipolar configuration warrants the end electrodes only to be connected to busbars; there is substantial reduction in copper requirement. In the present work, an electrowinning cell with bipolar electrodes and end electrodes, each having an area of 1000 cm2 was designed and operated. The bipolar electrode is made of mixed metal oxide coated titanium mesh welded to plain titanium sheet. Coated titanium mesh acts as anode and the plain titanium sheet acts as cathode. Environmentally unacceptable lead anode and the recurring loss of lead are done away with. Closer spacing of the electrodes, paves way for the application of higher current density leading to mass transfer enhancement. Performance of bipolar copper electrowinning cell is reported.1. IntroductionThe normally adopted practice in electrowinning of copper is the conventional monopolar configuration. In this practice, the individual electrodes act either as anode or cathode. Hence there is a need to connect every one of the electrodes to the common anode or cathode busbar and crossbars running across the top of the cell are necessary. The common busbar carries very high current which is divided among the individual crossbars and hence has to be thicker in relation to the current load of the cell. The drawback of the need to use common busbars of thicker cross section and the need to have crossbars are obviated in the bipolar configuration."

Jan 1, 2009

By Dengfu Chen, Yi Yang, Chunmei Chen, Mujun Long, Shikai Gong, Junhao Sheng, Tao Liu

The relationship between thermo-physical properties of petroleum coke and temperature is of importance for determining of the operating parameters during the calcining graphitization process. In this paper, the variations of thermo-physical properties of petroleum coke versus temperature were investigated, such as the DSC-Tg curve, the specific heat capacity, the thermal diffusion coefficient, the thermal conductivity, and so on. The thermal analysis curve of petroleum coke showed synchronous thermal hysteresis at higher heating rates, indicating that a larger heating rate will cause delay of thermal effects. The thermal diffusivity of petroleum coke decreased during the calcining process. With increasing temperature, coefficient of heat conductivity and specific volume heat of the petroleum coke increased with a decreasing variation rate. The research provides a database for the calcining graphitization process of petroleum coke.

Jan 1, 2015

By M. E. Reed

Clyde Materials Handling (CMH) and WorleyParsons have developed a concept for a flash furnace feed system using the specialist pneumatic conveying equipment expertise of CMH and the flash furnace process experience of WorleyParsons. CMH has developed a proprietary volumetric feeder (called a Rotofeed) which is extremely accurate and overcomes many of the problems inherent with loss-in-weight screw feeders and drag chain conveyors, previously regarded as state-of-the-art. Initial indications are that the Clyde-WorleyParsons Feed System could deliver the following benefits to Flash Furnace operation: ? Accurate pulse-less delivery of feed material to the head of the burner leading to improved combustion performance and process stability; ? Highly accurate split to the individual quadrants of a conventional burner tube, or provision of a smooth hollow curtain to a burner without guide vanes; ? Decreased pressure pulsation in the furnace due to improved combustion control and performance; ? Decreased temperature fluctuations in the furnace due to improved combustion characteristics and hence reductions in refractory thermal stress and wear; Plant measurements have indicated a correlation between the discharge of concentrate from the drag chain conveyor and high speed pressure fluctuations in the flash furnace settler. Pilot scale test have been conducted to illustrate that the system delivers pulse-less feed to the burner with even feed distribution axially.

Jan 1, 2006

By Jens Decker

"In consideration of energy savings the ideal refractory furnace lining should possess the following features:??Lowest thermal conductivity possible in order to avoid heat loss.??Single component lining in order to allow freeze plane changes caused by wear, infiltration and temperature changes of the furnace.??Resistance against mechanical wear from cleaning tools and stirring in order to allow maximum output without equipment downtime due to maintenance.??Resistance against thermo-chemical attack from aluminum and alloying elements.However, refractory materials with a low thermal conductivity typically possess a higher porosity and this leads to lower strengths and resistance against chemical attack and wear. Hence, as a compromise, multi layer linings are required in order to meet energy saving standards.In this paper we present the features of chemically phosphate bonded dense and light weight refractories and how such refractories can contribute to energy savings.IntroductionIn several reports, the U.S Department of Energy published theoretical energy requirement limits for aluminum production as a future target, with recommendations on how to reduce energy losses. The reports provide a basic description of the processes and equipment involved, their interrelationship, and their effects on energy consumed. The report uses onsite process measurements as benchmarks that industry uses to compare performance between facilities and companies [1]. The energy consumptions used in this paper are primarily based on numbers published by the Department of Energy. However, their reports do not consider the potentially significant energy losses from process interruptions due to a lack of preventive maintenance and material deterioration over time. Further, the Department of Energy reports do not consider equipment costs and availability. Energy input to metal output depends on factors beyond energy losses through the furnace wall. For instance, a focus on energy savings should consider fixed output costs due to depreciation of the equipment and the plant."

Jan 1, 2009

By Kim Fagerlund

A novel apparatus for studying refractory infiltration and dissolution/degradation under a temperature gradient was developed. To supersede conventional isothermal refractory testing, a new temperature gradient technique, based on a crucible equipped with a cooling element, has been developed to provide practical information on the penetration and dissolution of refractory materials under cooled conditions. This technique was adopted and applied to several refractory-slag systems. Commercially available magnesia chrome refractory bricks against a copper-containing calcium ferrite type of slag were tested and compared using both a conventional crucible test and the new temperature gradient method. The experiments were conducted at 1300-1420°C under a controlled atmosphere of nitrogen or air. It was noticed that the type of porosity has a significant effect on infiltration of magnesia chrome refractories. Furthemore, the copper-containing calcium ferrite slag caused a severe slag attack and refractory failure in some cases, due to its fluidity and corrosive nature.

Jan 1, 2002

By J. W. Dini

Introduction The mission of the Materials Fabrication Division (MFD) is to provide fabrication services and technology in support of all programs at Lawrence Livermore National Laboratory (LLNL). MFD involvement is called for when fabrication activity requires levels of expertise, technology, equipment, process development, hazardous processes, security, or scheduling that is typically not commercially available. Customers are encouraged to utilize private industry for fabrication activity requiring routine processing or for production applications. MFD is .a large diversified service organization including approximately 400 full time employees. The group provides a wide variety of processes including all common machining and fabrications operations, laser and water jet cutting, electrical discharge machining, lapping, electron beam and laser welding, vacuum brazing, heat treating, forming, electroplating and metal finishing, optical polishing and grinding, vacuum coating, vacuum engineering and a variety of plastics operations. These operations occupy more than 1,250,000 square feet of floor space. For more detail on the many fabrication related services available from MFD, see Reference 1.

Jan 1, 1992

By Bora Derin

Optimization of slag composition has great importance on effective and clean metal production technologies. Reddy-Blander (RB) model, a priori, is very useful tool for prediction of impurity capacities of industrial slags. In this study, sulfide capacities (Cs) of 19 lead smelter slags indicated in the literature were calculated and effects of Cs values on sulfur content of lead bullions were discussed.

Jan 1, 2006

By Thomas Niehoff

Many industrial processes require energy. Energy is required for melting or heating purposes. The heat can be generated by electrical heating or combustion/oxidation of hydrocarbons. Oxygen supports the combustion process. Oxygen is naturally contained in air with about 21 vol.-percent. The use of technical oxygen will allow an increase to the natural oxygen concentration of combustion air. Altering the combustion process by increasing the oxygen content has various effects. These effects are described and analyzed with regard to heat transfer, emissions and energy consumption. Industrial processes requiring oxyfuel are described and discussed regarding energy aspects.

Jan 1, 2008

By Kang-In Rhee

Nonferrous metal recycling not only provides energy saving and environmental benefits but also is a significant factor in the supply of various types of metals used in our society. Recycling plays an important role in establishing the sustainability of materials. The total amount of recycled nonferrous metals by weight accounts for less than 5% but their value is larger than 50% compared to ferrous metal recycling which consists of about half of the total metal recycling in weight. This paper describes trends and typical achievements in nonferrous metal recycling and overviews the present and future of nonferrous metal recycling technology and business in Korea.

Jan 1, 2006