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By R. W. Lawrence

A high rate biological reduction technology has been developed to provide low cost hydrogen sulphide for various uses in water treatment and metallurgical processes. Commercial operations produce sulphide safely at a fraction of the cost of chemical sulphide. The biologically produced H2S is used for treatment of acid wastewater and selective metal recovery whereby metals present in wastewater streams are recovered in high grade metal sulphide concentrates that are sold to smelters. The combination of biological H2S production and selective metal recovery is currently marketed under the process name BioSulphide-Thiopaq. The process can be applied on a stand-alone basis or in conjunction with a conventional lime water treatment. Process advantages include: reduced lime treatment costs, reduced volume of waste sludge free of toxic metals leading to reduced long term environmental liabilities, selective recovery of metals and, in some cases, net profit from water treatment achieved through the sale of metal concentrates. Three case studies are presented to provide examples water treatment and metal recovery: the Caribou Mine, New Brunswick; the Phelps Dodge Bisbee operations, Arizona; and Falconbridge?s Raglan nickel mine in Quebec. A fourth case study is presented to highlight environmental control for treatment of ARD in the Leadville mining district of Colorado. Process flowsheets, capital and operating costs are presented for the four case studies

Jan 1, 2003

By A. R. G. Azevedo, G. C. Xavier

"This work has for objective to identify the soil of the neighborhood Codin located in a lacking area of the urban nucleus of the district of Campos dos Goytacazes - RJ, after the identification the best line was determined for the production of soil-cement blocks. In this area it happens habitational deficit and precarious constructions are also verified. The use of soil cement blocks is considered a cheaper constructive method than the conventional (ceramic block or of concrete), because one of the components of the raw material is abundant (the soil) and the constructions can be erect with certain easiness for collective effort regime. Samples of soil of this area were collected for they be characterized with relationship to the physical and chemical characteristics, with I aid of GPS the community's location it was registered. Identified the soil type, the work began the study of lines they to make possible your use in an economical and safe way. For that were made drained blocks in the format 19,5x10x5 cm, with lines containing the addition of 5% and 10% of cement in volume, and as parameter of quality the absorption of water and the resistance to the compression were measured, following the Norms of ABNT.IntroductionWe know that the use of the soil by the humanity come from the antiquity. And ifs confirmed by the archaeology places of the old civilizations of the word. The most remote constructions date from 10.000 years old in Jericoh, in the Jordan River Valley. This work became more intensive at 3.000 B.C. (Before Christ), by people who lived in those valleys with mood areas, a lot of clay and washed by the rivers.Almost all the sectors of engineering of soils choose the stability to use the local soil. Although, artificially treated, offers more economical advantages.The stability of a soil consist of endow it of the condition to resist the deformations and ruptures during the period that it is being used, because these characteristics are necessary in any construction.The application of the natural soil only is possible in places that they are of good quality and attend to the requirements of engineering to the type of previewed application. The granulemeter correction and the chemical stability include cases of inappropriate soils areas, turning the soil able to be used as construction material. Among the stability agents, usually added to the soil for stability ends, the cement is indicated."

Jan 1, 2013

By D. Norman, D. J. Hughes, R. Dashwood, I. McGregor, N. D. Raath

"This paper develops a methodology for predicting spot weld fractures in automotive boron steel grades, such that fracture modes can be predicted accurately in a vehicle or sub-assembly structure. To achieve this, it was necessary to understand the range of complex fracture modes observed in boron steel spot welds and how these are linked to the Heat Affected Zone (HAZ) microstructures and hardness distributions and residual stress.Material data for the HAZ was extracted by simulating the spot welding process using a Gleeble machine; achieving specific weld microstructure in a larger volume which was used in destructive testing. Neutron diffraction was employed to accurately characterize the post-weld residual stresses found inside the weld. The constitutive relations of specific areas in the HAZ where fracture is thought to occur is being incorporated into finite element software to improve fracture prediction of boron steel welds.IntroductionWith the drive for light-weighting and improving passenger safety, lighter and stronger materials are being continuously sought in the automotive industry. The application of boron steel in the Body-In-White (BIW) meets both these criteria by down-gauging thickness of the steel and increasing the strength. As an example, when applied to crash-relevant areas in cars, components have an ultimate tensile strength of 1500 MPa, minimum springback and reduced sheet thickness.To achieve high strength and low springback, boron steel components must be formed and hardened at the same time. This is typically achieved by austenitizing the steel around 900 °C and simultaneously quenching and forming, usually with a hydraulic press and tool-set. Trace amounts of boron, typically 0.005wt%, increase the hardenability of the steel dramatically. This is attributed to the grain boundary segregation of boron, which hinders the formation of ferrite during cooling and forces the transformation of austenite to martensite at high cooling rates, a minimum of25 °C/s."

Jan 1, 2013

By Tetsuro Sakai

Home appliance recycling law was put into force in April 2001 in Japan. Specified kinds of home appliances, such as air conditioners, television sets, refrigerators and washing machines, should be recycled according to the law. Mitsubishi Materials Corporation (MMC) in cooperation with home appliance manufacturers is operating five home appliance recycling plants in Japan. MMC established complete treatment system of recyclable materials generating from home appliance recycling plants, which is formed by unique collaboration among home appliance recycling plants, copper smelter and refinery, and cement plants. Recyclable materials containing copper and precious metals are only handled and treated within the MMC group. By using this lock-in system, safe treatment and traceability of materials are guaranteed as 100% materials recycle.

Jan 1, 2008

By R. D. MacDonald

The papers presented in this chapter cover a wide range of hydrometallurgical topics and might be considered to be unrelated to each other. All of the authors, however, utilized the basic methods of process mineralogy to characterize the reactants in their experiments and the products produced. The wide range of research topics which can be pursued successfully by the use of the methods of process mineralogy is a matter of interest in itself. One might speculate that the methods could be even more widely applied if only their utility were better recognized. These methods for characterizing reactants and products include principally x-ray diffraction, optical micros-copy, wet chemical analyses, instrumental chemical analyses, high intensity magnetic separation, micro-scale gravity separation, differential thermal analysis, micro-hardness testing, and judicious use of the sledgehammer and cold chisel. It is perhaps not by coincidence that most of the papers in this chapter were prepared not by mineralogists, but by hydrometallurgists, who are recognizing the importance of thinking in terms of mineral phases, and not just assays! It appears that the gap between process mineralogy and the mineral industry is closing, and that future AIME sessions promise to become established forums where mutual discussion of such topics as metallurgical "troubleshooting" and process design may become commonplace between plant engineer and process mineralogist.

Jan 1, 1981

By D. Maurice, W. D. Riley, J. A. Hawk

"The increased penetration of wrought aluminum into the automotive market is stimulating a need to separate wrought aluminum from cast aluminum because of: a) the additional value of scrap wrought alloys and b) the increase in the total amount of aluminum automotive scrap will outstrip the demands of secondary aluminum foundry industry. The availability of clean fractions of wrought and cast aluminum and incidentally, a clean cast magnesium fraction will allow increased recycling of aluminum used in the automotive industry.Hot crushing has been tested previously and proposed as a means to separate cast from wrought alunrinum product. The underlying concept is that when a mixture of cast and wrought aluminum is thermally processed and then subjected to crushing action, differences in toughness between wrought and cast aluminum alloys will become more pronounced. Hence, it should be possible for conditions can be established such that the cast material fragments, while the wrought material, having lost much less of its toughness, merely deforms. The two types of product could then be separated by simple sizing methods.In this paper we report on the testing of this concept. We were unable to replicate the results which originally demonstrated proof of concept. Possible reasons for this are discussed, as well as the possibility that the original results may not be as desirable as the current results for subsequent sorting."

Jan 1, 2000

By Pieter Steeneklm, Mazi’ Rejaee

"EXECUTIVE SUMMARYThe automotive industry's search for increased fuel efficiency through component weight reduction has driven the growth in consumption of magnesium metal in the form of die cast alloys. This trend, which began in North America and should soon accelerate in Europe, will require enhanced recycling services since each tonne of metal used for die cast parts production produces about 500 kg of scrap.Currently, the European die cast market is plagued by very high tolling prices for scrap recycling due to lack of competition and high transport costs due to the distances between the scrap generator and the recycling facility. This situation clearly increases the cost of magnesium die cast components and reduces magnesium's competitiveness with other materials. The challenge for the magnesium industry in the short term is to provide cost ·effective recycling solutions for the die cast industry. In addition effective recycling, in the medium to long term, is needed for the anticipated large volumes of secondary or used scrap that will become available as the die cast components reach the end of their life cycle. This paper will present The Antheus Integrated Magnesium Project as a Novel approach addressing some of the key recycling related issues facing the magnesium industry, in particular the die casters. The paper outlines the many advantages of an integrated magnesium metal park, in an overall goal of increasing magnesium metal's competitiveness."

Jan 1, 2000

By Oleg I. Platonov

The process for desulfurizing coke oven gas in a regenerative system ?scrubber-stripper?, with sour gas being fed to Sulfur Recovery Unit (SRU) and tail gas being recycled to raw coke gas scrubber, has been developed. A key problem of this process is the presence of elemental sulfur in the SRU off-gas, which may deposit on gas-blowing equipment, thus disrupting its operation. A new treatment technology for SRU off-gas that has been worked out for a Claus unit operated by «Russian Metallurgical Company» (RMC) in Magnitogorsk (Russia) is presented. It incorporates a catalytic hydrolysis/hydrogenation stage, where all sulfur-bearing species such as sulfur dioxide, carbonyl sulfide and elemental sulfur are converted to hydrogen sulfide. The SRU in Magnitogorsk comprises three main units: gas re-heater; catalytic hydrolysis reactor and waste gas cooler. Re-heater is required to increase temperature of the process gas up to a level of catalytic conversion (beyond 330-3500C). Oxygen utilized as an oxidizing agent reduces the volume of waste gas to a minimal possible value. The operational data garnered since 16.07.2004 clearly shows that the new technology allows high-level purification of Claus tail gas from elemental sulfur. Unlike SCOT ? process, this technology does not require separate stages for H2S removal and enrichment that tangibly simplifies its implementation at lower capital and operation expenditures.

Jan 1, 2006

By Xie Gang

The leaching experiment used by bacteria on the low grade sulfide copper ore which is difficult to leach was carried out. Some leaching bacteria which have good physiological and leaching activity were isolated and domesticated, and were adapted to leaching ore. The effective domesticated method was put forward. Some technological parameters such as ore acidification, potential controlling, leaching method, ore granularity, leaching acidity, leaching liquid quantity and acid consumption were obtained by column experiment and leaching ore in situ under the ore well. The results show it could leach 30.62% of copper from the low-grade sulfide copper ore within 24 weeks by column leaching method, and the bioleaching rate of copper is 22.83% by leaching in situ under the ore well in 8 months.

Jan 1, 2006

By Jiann-Yang Hwang

The economic growth in new developing countries such as China and India has stimulated strong demands in basic materials such as steel. World steel production has exceeded the milestone of a billion tons a year recently. However, the blast furnace technology, which was invented in 1340 A.D., is still the fundamental route for today?s steel production. It is important to develop a new generation of steelmaking technology that can meet the society?s needs from the energy, environmental and economic standpoints in the 21st century. The new microwave and electric arc heating technology discussed in this paper provides a totally different mass and heat transfer mechanism from the conventional blast furnace technology and offers a great potential to meet our society?s needs.

Jan 1, 2006

By T. J. A. Smith

This paper provides an overview of some of the key issues in design of smelter gas handling systems, with particular reference to sulphide smelting plants. In both primary smelting and converting. gas handling and treatment systems often represent the major capital cost component. There is also ample evidence that poor system design can be a major cause of smelter down time, lost production and unforeseen high maintenance costs. The paper discusses these issues and offers guidance for improved design.

Jan 1, 1992

By John J. Friel

Digital imaging systems are particularly useful in microscopy, because they make it possible to extract information not readily accessible by manual methods and to display that information clearly. Computer-aided imaging systems analyze, process and compare images, and of these, image analysis is most useful in materials science. Image analysis quantifies the microstructure by making measurements on the entire field or by measuring the size and shape of features individually. Even true surface area can be calculated. Modem image analyzers make thousands of measurements in seconds, leaving the investigator to interpret the data and relate them to process and material properties. Image processing, which may be necessary to prepare an image for analysis, includes everything from simple contrast transforms and kernel filters to complicated processes such as grain boundary reconstruction using artificial intelligence. An example of image comparison is point-by-point screening of X-ray maps of different elements to extract phases. In all of these operations, the computer makes a large number of measurements in seconds and returns information that could not be realistically obtained by manual methods.

Jan 1, 1992

By Guo Xian Jian

In this paper, an alternative process to recover the value metals from polymetallic gold ore by FeCh leaching was proposed. In the process, gold was recovered by direct cyanidation from the leaching residue, the isolative electrolyte in chloride solution was selected to recover lead, the cementation with copper powder was used to recover silver and the solvent extracting was applied to recover copper and zinc. The total recovery of gold, lead, copper, silver and zinc in the process is 90.8%,96.05%,84.3%,81.98% and 54% to the bullion of gold, lead and silver and sulfate of copper and zinc, respectively. The process conditions selected for FeCh leaching are the temperature of 104°C, leaching time of 6 hours, Fe3+ content of 140 g/l and stoichiometry of FeCl3.

Jan 1, 1996

By Robert F. Jenkins, King G. Robertson

This paper presents a practical approach for utilizing a computer model to determine the mass balance for a typical UBC recycling complex - starting with raw materials input, through scrap preparation, delacquering, melting, alloy adjustment and casting. This model is especially concerned with metal unit losses throughout the recycling complex with emphasis on metal losses at the melting furnace. The model also addresses the application of hardener alloys, metallurgical salts, chlorine for demagging, and reagents for acid gas emissions control. Other issues addressed are dross generation, acid gas emissions and dirt and fines to landfill. One benefit of the model is the conversion of annual production objectives to hourly production rates and resource requirements taking into account production schedules, maintenance downtime, and operations inefficiencies.

Jan 1, 2000

By Ryuhei Masuda, Kenji Oosumi, Yasuhiko Watanabe, Yutaka Nagakura, Tomoya Ohzono

"In order to promote recycling of aluminum scrap, it is required to remove inclusions that have a remarkable influence upon the product quality. An internal filtration technology using a new filter, which is made by coating an adhesive on the surface of the conventional filter, has been developed as a new removing technology for inclusions.The technology has made it possible to remove inclusions as small as 10-20µm in the molten metal, which have been impossible to be removed by the surface filtration technology using conventional filter, An inclusion removal rate of up to 90% has been attained.The technology will contribute not only to recycling of aluminum products but also to the improvement in the quality of current products."

Jan 1, 2000

By V. V. Kutumbarao, M. T. Nimje, G. Balasubramanian

Wastes from the aluminium industry such as red mud from the alumina refinery, fly ash from the captive power plant and spent pot lining from the smelter, have been successfully converted into glass-ceramic products. The process involves addition of a small quantity of glass former along with traces of nucleating agents to aid crystallization, to a specific mixture ofred mud, fly ash and spent pot lining, followed by melting at around 1300°C and vitrification by cooling. The resultant glass is then converted into a glass- ceramic by a suitable heat treatment at around 700 - 750°C. The glass-ceramic products show excellent wear resistance, besides possessing an aesthetic appearance. The major application foreseen for such products is as decorative tiles in the building industry.

Jan 1, 2000

By Vadim J. Jabotinski

This paper describes several areas of application for electron beam processing of materials. The technology and use of electron beam systems in gas phase synthesis reactions are described. Gas phase reactions may be used to generate ultra- fine metal or ceramic powder that are very pure and crystalline. Among the examples presented are: the generation of nanometer sized metal powders and the gas phase synthesis of silicon carbide for silica and methane. The experimental system is described and future theoretical and experimental objectives are identified.

Jan 1, 1998

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 Lidong Teng, Seshadri Seetharaman, Aida Abbasalizadeh

0In the present paper, the feasibility of the recovery of dysprosium from spent Nd-Fe- B magnets containing approximately 9 wt% Dy was investigated by using molten salt process. The salt bath consisted of a mixture of NaCl-KCl-LiCl corresponding to the ternary eutectic composition. AlCl3 was used as a chlorinating agent in order to enable an efficient dissolution of metal in the molten salt phase in the salt bath. The metal chloride which is formed as the result of chemical reaction between the metal in magnet and AlCl3, is subsequently subjected to electrolysis in order to be deposited on the cathode. Graphite rods were dipped in the salt bath as electrodes and alumina crucibles were used as the containers for the electrolytic cells.

Jan 1, 2014

By Henrlk Gripenberg

To solve the environmental and financial problems of the traditional Rotary Salt Furnace process, a new salt-free method for aluminum dross and scrap melting, ALUREC, has been developed by AGA and its partners, Hoogovens Aluminium and MAN GHH. AGA and Hoogovens Aluminium developed the main process concept and jointly carried out trials on pilot plant scale. Owing to excellent results" the partners decided to jointly erect a commercial scale test plant. The order for the design and erection of the furnace went to MAN GHH. The three companies designed the test plant and began operation in the spring of 1994. The results have been excellent and the process is expected to be a technical and commercial success.

Jan 1, 1995