An economic evaluation of the FOS process

Detailed analyses of capital and operating costs for Fuel-Oxygen-Scrap (FOS) furnaces and electric-arc furnaces (EAF) ranging in productive capacity from 14,000 to 170,000 tons per year are presented. A discussion of the influence of oxygen requirements on costs and how this affects the economics of the FOS process is included. Cost estimates for the FOS installation are based on British economic conditions and results from a 5-ton experimental furnace.     

镀锌钢管湿式内吹消烟除尘系统

设计的镀锌钢管湿式内吹消烟除尘系统结构简单、投资少、运行费用低、净化处理效果好。介绍了该系统的结构及其工作情况。     

Treating waste with PAM

The plasma-arc melter system can be designed for essentially all solid waste, depending on the economics and the waste to be treated. The capital costs as well as the operating costs and revenues of these systems are equivalent to waste-to-energy plants. As a paradigm shift of conventional technology, however, the first commercial plant has yet to be built. For more information, contact T.L. Eddy, MeltTran Incorporated, 1293 East 65th, North, Idaho Falls, Idaho 83401; (208) 524-6358; fax (208) 523-1049.     

Copper smelting in Boliden’s Rönnskär works described

As much of the production as possible in Ronnskar works is handled during the day shift. This requires three times as large furnaces and casting machines as three shifts and involves a considerable outlay of capital, but the labor force is reduced approximately two thirds with production costs decreased to a corresponding degree.     

Economics of continuous casting in a converter steel plant

The integration of continuous casting with converter and electric arc furnace steelmaking practice for relatively small tonnages: capital and operating costs are here analyzed. The range of application of continuous casting can now be firmly assessed, and recommendations are based on the practical experience and achievements of the past ten years.     

The Present Position of Bright Nickel Plating in England

The selection of a pretreatment and conversion coating cycle for any application is subject to many considerations, including anticipated environmental service conditions, life of finished article, type of finish to be applied, condition of metal surface prior to pretreatment, design of article to be treated, throughput required, space and/or equipment available, capital costs, operational and maintenance costs. The characteristics of various types of pretreatments and conversion coatings for ferrous and non ferrous metals are discussed in relationship to the above considerations. It is suggested that the final selection will be on economic grounds from processes of adequate technical merit but subject to any site limitations.     

Alkaline and acidic autoclaving of refractory gold ores

American Barrick operates two autoclaves for the processing of refractory gold ores. Because of the mineralogy of the ores, one autoclave is alkaline and the other acidic. The pH of operation has a significant effect on materials of construction, as well as capital and operating costs. The following summary concentrates on the practical and economic aspects of such operations.     

论现代双线干油集中润滑系统的高压化趋势

本文论述了双线干油(脂)集中润滑系统的发展简史和现代高压双线干油集中润滑系统,并对低压(138bar)、中压(210bar)和高压(400bar)系统的管路内润滑脂滞留时间及它们的综合投资费用和经济性等进行了分析比较,阐明了其高压化趋势的原因。     

Selecting an oxygen plant for a copper smelter modernization

The selection of an oxygen plant for the Cyprus Miami smelter modernization project began with a good definition of the use requirements and the smelter process variables that can affect oxygen demand. To achieve a reliable supply of oxygen with a reasonable amount of capital, critical equipment items were reviewed and reliability was added through the use of installed spares, purchase of insurance spare parts or the installation of equipment design for 50 percent of the production design such that the plant could operate with one unit while the other unit is being maintained. The operating range of the plant was selected to cover variability in smelter oxygen demand, and it was recognized that the broader operating range sacrificed about two to three percent in plant power consumption. Careful consideration of the plant “design point” was important to both the capital and operating costs of the plant, and a design point was specified that allowed a broad range of operation for maximum flexibility.     

推行项目代建制控制政府投资项目造价

指出目前政府投资的项目,通常是由基建指挥部来管理.由于管理不专业,经验不能积累,致使造价易失控.而项目代建制,通过选择合适的代建单位,利用代建单位较强的专业力量,依据其权威的合同文本,对项目进行有效地管理,抵制腐败的产生,是一种新型的项目管理模式,值得进一步推行、推广.     

Applying Ausmelt processing to complex copper smelter dusts

Ausmelt technology opens up new opportunities for the economic processing of complex copper smelter dusts. Not only can the technology separate more of the unwanted elements to produce a clean blister copper for refining, but it can also allow production of fume and precious metal products that can be readily upgraded to produce high-grade, valuable products. Developments in the processing of copper-bismuth-gold flue dusts left over after the smelting of bismuth-bearing concentrates in flash furnaces are described, including pilot-plant trials and process and equipment development. Design considerations and capital and operating costs for the proposed plant are discussed.     

The economics of inert anodes and wettable cathodes for aluminum reduction cells

Estimating the impact of inert-anode and wettable-cathode technologies on smelter costs must be speculative because no such technologies have yet been commercialized. Even so, some broad conclusions can be drawn about the economic merit of inert anodes in retrofit and greenfield smelter scenarios. Study suggests that retrofitting inert anodes to existing prebake cells generates insufficient economic benefit to justify this objective. Drained cathode cells offer potential for energy savings coupled with increased production, provided that the cell life is greater than three years. Unlocking the potential value of both inert anode and wettable cathode materials will require their use in vertical electrode configurations, where the impact on operating costs and, particularly, capital costs, is expected to be significant. To be economically and technically viable, vertical electrode cells will require wear rates of less than approximately 5 mm per year on the inert electrode surfaces, much less than has so far been reported. For more information, contact Jeff Keniry, Alumination Consulting Pty. Ltd., 2 Governors Drive, Mt. Macedon, VIC 3441, Australia; +61-3-5426-4124; fax +61-3-5426-4248; e-mail jkeniry@netcon.net.au.     

World copper solvent extraction plants: Practices and design

This article compiles the results of a review of world copper solvent extraction (SX) plant practices and examines changes in operating practices in the last seven years as compared to previous world copper SX surveys in 1996 and 1999. Trends covered are fiber-reinforced plastic construction mixer box and settler designs, reverse flow settlers, and advanced mixer design. These changes have resulted in improved capital and operating costs. For more information, contact Tim Robinson, Phelps Dodge Mining Co., Process Technology Center, 9780 E. Sanchez Road, Safford, AZ, 85546; e-mail trobinson@phelpsdodge.com.     

How will biomining be applied in future？

This paper reviews the current status of commercial biomining operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges to exploiting these innovations, and concludes with a discussion of biomining＇s future. Biomining is commercially applied using engineered dumps, heaps and stirred tanks. Overcoming the technical challenges of lowering costs, processing low-grade, low-quality and complex ores and utilizing existing capital investments at mines requires better understanding of microbial activities and innovative engineering. Surmounting biomining commercial challenges entails improved mining company/biomining innovator cooperation and intellectual property control.     

Routes to residue-free zinc refining

Present zinc refining in sulfate circuits creates considerable amounts of residuals that are often disposed in densely populated sites around the world, creating disposal and environmental liability issues for producers. A combination of chloride and sulfate circuits offers attractive possibilities for residue-free zinc refining, resulting in lower capital and operating costs for producers. For more information, contact G. Van Weert, OreTome Limited, 16668 Humberstation Road, R.R. No. 3, Caledon East, Ontario, Canada L0N 1E0; (905) 880-3142; fax (905) 880-3748.     

Comparison of plasma-sprayed coatings produced in argon or nitrogen atmosphere

When spraying is conducted at ambient atmosphere, the entrainment of air cools the plasma jet and affects its expansion. It can also cause oxidation or chemical decomposition of the sprayed materials. Inert plasma spraying (IPS), generally conducted in an argon atmosphere, prevents these phenomena. However, the main drawbacks of IPS in comparison with air plasma spraying are the capital and operating costs. This paper presents a study in which nitrogen is used as a substitute for conventional argon atmosphere, thus reducing costs by 25 to 30%. Titanium carbide and niobium powders were sprayed in both argon and nitrogen atmospheres. Cryogenic cooling of the substrate was used during the spray process. This helps to maintain a low temperature in the chamber, produce thick coatings, and allows the use of substrate materials that are sensitive to heat. The velocity, temperature, and composition fields of the argon-hydrogen plasma jet flowing in argon or nitrogen at atmospheric pressure are compared from numerical simulation. The adhesion, roughness, and microstructure of the niobium and TiC coatings produced in both atmospheres are discussed as well as their nitrogen content.     

Magnesium: The first quarter millennium

Conclusion  From its early beginnings the magnesium industry has been a turbulent industry driven by wars in the early 20th century followed by periods of slow growth. The dominant technology has changed to suit local economics. In recent years, the trend toward globalization has produced a discontinuity in the traditional industry supply pattern. To match the economics of the Chinese and former CIS magnesium industry, Western producers will have to

Non-wetting behaviour of tungsten carbide powders in nickel weld pool: new loss mechanism in GMAW overlays

This paper presents a new mechanism, observed directly for the first time, to explain low carbide fractions in Ni–WC overlays produced with GMAW. In this loss mechanism, a significant amount of powder loss is a consequence of the non-wetting behaviour of tungsten carbide. High speed videography and quantitative metallography of weld deposits are used to identify this mechanism. The non-wetting mechanism found acts simultaneously with the carbide dissolution mechanism, which until now was the only suggested cause of low carbide fraction in GMAW Ni–WC overlays. The non-wetting behaviour is observed in both short circuit and free flight metal transfer, accounting for carbide losses between 20 and 70% in the experiments performed. Low carbide fraction has prevented the mainstream use of GMAW for Ni–WC overlays, despite the advantages of simplicity, capability of in situ repair, and low capital costs. The findings presented here have a potential large impact for further consumable and process development.     

Richtlinien für Werkstoffauswahl und Korrosionsschutz in der chemischen Industrie

Criteria for the selection of materials and corrosion protection in the chemical industry In chemical technology, the technical requirements to be met by materials as well as the protection measures against corrosion become more differentiated. On the other hand, owing to the technical progress in the sphere of materials number of alternative solutions to cope with these specifications is becoming available. The selection process, which has thus become more difficult, must lead to an overall solution representing the economic optimum; but must not become too expensive in the planning of new plant or in the corrosion protection of existing plant. A distinction is made between, and a brief outline given of, several stages in the material selection process, viz. formulation of requirements; selection methods prior to testing; laboratory tests; utilisation of technical testing plants; tests under operating conditions; determining the correct solution. The economic calculations designed to determine the most favourable technical solution call for numerous technical data (e.g., the corrosion rates under different corrosion conditions) as well as economic data (especially the capital and annual costs depending on the material). The calculation and estimating methods suitable for this purpose are described in detail. In order to reduce the costs incurred through corrosion, money must be spent on certain protective measures. This relationship is illustrated by the phenomenon of cost substitution. Finally, a synopsis is given of all the practicable methods suitable for determining the optimum conditions.     

Praxair’s dilute oxygen combustion technology for pyrometallurgical applications

Dilute oxygen combustion (DOC) technology uses separate high-velocity fuel and oxygen jets to generate strong in-furnace gas recirculation, producing combustion between the fuel and a highly diluted oxygen and furnace-gas mixture. These very low NOx oxy-fuel burners have been developed and commercially demonstrated in steel reheating furnaces. The burner design meets industry needs for increased productivity and lower operating costs with minimal capital expense and low maintenance. The performance of DOC technology has been measured under laboratory and industrial conditions encompassing both natural gas and coke oven gas firing, and a wide range of furnace temperatures and nitrogen levels that simulate air infiltration. This paper describes the results of the tests using natural gas as the fuel and lists potential applications for DOC technology in the non-ferrous metals industry. For more information, contact A.C. Deneys, Praxair, Inc., Applications Research and Development, 777 Old Saw Mill River Road, Tarrytown, New York 10591; e-mail Adrian_Deneys@Praxair.com.