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By Omid Marzoughi

Chromium has a wide range of applications, including as an alloy addition in various steels and also as a corrosion resistance coating. Carbothermal reduction of chromite ore (FeCr2O4) in a submerged arc furnace is an important industrial process for extracting chromium, but the energy consumption is excessive. It is suggested that one area for future research is the low temperature carbothermic solid state reduction of chromite to produce an intermediate product, which can subsequently be upgraded to ferrochromium. In this regard, a thermodynamic model has been developed to investigate this process and the effects of temperature, carbon additions and ore composition on the recovery of chromium and the grade of the ferrochromium, have been studied. Further development of the model may allow it to be applied to the simulation of other processes for the recovery of chromium from chromite ores.

By David G. Dixon

Although the kinetics of leaching processes are of paramount importance in the design and analysis of nearly all hydrometallurgical flowsheets, these concepts remain poorly understood and, as a result, are only rarely applied to mass and heat balance models. In this second of two papers, we demonstrate how simple yet powerful models of leaching kinetics and other rate processes may be added to mass and heat balance models, and apply these concepts using a spreadsheet model of a simplified pyrite autoclaving flowsheet. In particular, we focus on the interpretation and scale-up of batch leaching data, and on simple means for modeling other phenomena commonly associated with leaching, such as reagent depletion, gas-liquid mixing, and the precipitation of oxides and basic salts.

Jan 1, 2002

By Mototsugu Matsuno

A new process has been developed to treat fly ash generated from municipal incinerators, which contains not only toxic metals such as lead and cadmium, but also dioxins. The process includes the following steps; fly ash is formed into green pellets with some additives and the pellets are then roasted to eliminate or stabilize the toxic metals and to decompose dioxins. A pilot plant with a capacity of approximately 100 kg/hr was used to test the process. The tests verified that heavy metals were either volatilized or stabilized and dioxins were decomposed by high-temperature roasting. The pelletized ash was found to be non-toxic, so that it can be recycled as artificial lightweight aggregate. It was also found that volatilized metals collected as secondary ash can be recycled as smelting resources.

Jan 1, 2003

By Robert D. Pehlke

"Current continuous casting processes are going through a rapid evolution of advances and new developments. At the same time, intense efforts are being directed to the development of radical new technologies such as continuous casting of thin slabs and strip steel.Traditionally, the casting processes for steel have been anticipated by the development and implementation of processes in the non-ferrous industry. This trend is reviewed and what it may portend for steel is described.IntroductionThe continuous casting of steel has been a widely adopted process in the production of steel. The concepts for this processing go back into the early and mid 1800's; however, commerical development was delayed for a variety of reasons until the mid twentieth century.Beginning in the early 1960's, adoption of continuous casting was initiated and continues at this point in time to be accelerated. In Japan, more than 90% of the steel produced is continuously cast (1). More than 50% of the steel produced in the United States is continuously cast and this fraction continues to rise (2). Numerous examples can be cited of installations costing well over $200,000,000 which have provided a payoff in less than a year and a half. As this process has continued to be applied and its technology to increase, computer control systems have been installed. In particular, in the larger plants producing slabs, sophisticated computer systems involving the integration and networking of mini-computers, micro-computers, and mainframe including back-up systems at all levels are being utilized. Pehlke (3), and Harabuchi and Pehlke (4) have described the structure of these systems."

Jan 1, 1988

By J. R. Kiji

The Cerro Matoso S.A. mine and smelter, in the Cordoba lowlands of northwestern Colombia, consist of a dedicated laterite nickel mine, ore blending, drying and an RKEF process to produce high-quality ferronickel. At a project investment of $400M, first production of ferronickel was in September 1982, and in its inaugural year CMSA produced 6,150 tons of contained Ni from a mined ore grade of 3.2% Ni. Initial operational difficulties resulted in a number of furnace run-outs, which impacted ramp up to design ore throughput of 128 dry t/h Since then CMSA has steadily incorporated process improvements and initiatives to take the single line operation to an ore throughput of 175 dry t/h. A second 175 dry t/h line was added in 2001 (investment of US$ 300M) to consolidate CMSA as one of the world's lowest cost Ni producers with an installed annual production capacity of 50-55,000 tons Ni. The most recent addition is commissioning of Phase I of an ore-upgrading project to counteract the effect of declining ore grades. Keywords: Laterite, ferronickel, pyrometallurgy, smelter.

Jan 1, 2004

By Torn H. Okabe

A fundamental study was conducted with the purpose of establishing an environmentally sound recovery process for recycling of valuable metals, by combining scraps containing such metals. As an example, direct extraction and recovery of neodymium (Nd) in magnet scraps was investigated by utilizing liquid metal as an extraction medium. It was found that liquid magnesium (Mg) is a suitable extraction medium and can extract Nd from iron alloys with high efficiency at around I 100 K. The newly developed extraction apparatus for Nd is a mechanically simple and static device without moving parts, where the Mg extraction medium circulates due to differences in the temperature inside the reaction vessel. This developed device can simultaneously accomplish continuous extraction of metal Nd from scraps, re-extraction of Mg from Mg-Nd alloy and the eventual recovery of pure Mg. As a result, metal Nd with 98 % purity was directly recovered from magnet scraps under certain conditions. It was also shown that the extraction agent Mg could be reused. The results of this investigation show the possibility of establishing a new process for the direct extraction of Nd in pure metal form without oxidization.

Jan 1, 2003

By Torn H. Okabe

A fundamental study was conducted with the purpose of establishing an environmentally sound recovery process for recycling of valuable metals, by combining scraps containing such metals. As an example, direct extraction and recovery of neodymium (Nd) in magnet scraps was investigated by utilizing liquid metal as an extraction medium. It was found that liquid magnesium (Mg) is a suitable extraction medium and can extract Nd from iron alloys with high efficiency at around 1100 K. The newly developed extraction apparatus for Nd is a mechanically simple and static device without moving parts, where the Mg extraction medium circulates due to differences in the temperature inside the reaction vessel. This developed device can simultaneously accomplish continuous extraction of metal Nd from scraps, re-extraction of Mg from Mg-Nd alloy and the eventual recovery of pure Mg. As a result, metal Nd with 98 % purity was directly recovered from magnet scraps under certain conditions. It was also shown that the extraction agent Mg could be reused. The results of this investigation show the possibility of establishing a new process for the direct extraction of Nd in pure metal form without oxidization.

Jan 1, 2003

By G. Mark Aylmore

Various processes have been developed using a combination of elevated temperature and chemical treatment processing to recover Li from silicate minerals. To facilitate further process development, a comprehensive understanding of the deportment of Li and associated minerals in ore bodies is essential to allow the industry to predict the response of ore reserves to metallurgical treatment options. This paper describes results from the integrated use of the John de Laeter Centre’s state of the art analytical and mass spectrometry techniques to characterise a selection of Li bearing ore bodies and determine their amenability to potential processing options for the extraction of Li. The mineralogy, mineral associations, and liberation characteristics of ore-bearing and gangue minerals were characterised using a combination of the TIMA and XRPD studies. The Li content and distribution within minerals were defined using LA-ICPMS and field emission scanning electron microscopy techniques (EBSD, ToF-SIMS) and atomic probe microscopy.

By A. Kontopoulos

Refractory sulfide gold ores or concentrates require an oxidation pretreatment step to yield the contained gold amenable to the subsequent leaching step. The process options for oxidation pretreatment can be broadly classified as follows: roasting, high or low pressure oxidation bacterial oxidation, chemical oxidation, each with a number of alternative suboptions. Roasting and high pressure oxidation are being applied on an industrial scale; the stage of development of the other options range from preliminary laboratory to advanced pilot plant- In this paper, the major technical, environmental and economic aspects of the above processes are being discussed. Future industrial trends will also be considered. Particular emphasis will be placed on the treatment of arsenical ores and concentrates, where safe plant operation as well as, handling and disposal of the arsenic containing products and/or effluents 'and residues is of paramount importance.

Jan 1, 1990

By Larry M. Southwick, Phillip J. Mackey, A. E. (Bert) Wraith, Albert Pelletier

In 1881, the first commercial pneumatic Bessemer-type converter treating copper matte was successfully introduced by Pierre Manhes at the Eguilles copper plant near Vedène in France. This development followed over a year of testing on a smaller scale at a foundry in Vedène, during which the vertical tuyeres of the conventional Bessemer converter had been successfully replaced by horizontal tuyeres in an effort to avoid the freezing of copper which had occurred in the bottom of the vessel having vertical tuyeres. The Manhes Converter, as it became known, was the first successful large-scale adaptation of the Bessemer concept of using compressed air blown into a melt for metal refining and treatment. Within a few years, Manhes Converters utilizing horizontal tuyeres in either the original type of vertical converter, or a later and more enduring horizontal barrel converter, were in operation at over a dozen copper smelters around the world. It was this process that Messrs Peirce and Smith essentially improved with the introduction of the larger converter which bears their name and the development celebrated at this Symposium. The present paper briefly traces the original development by Pierre Manhes in the early 1880s and which set the stage for the later Peirce-Smith adaptation. The paper observes that the original development by Manhes was in part driven by the need to reduce coal (energy) consumption and hence the production cost in order for Eguilles to remain competitive with the larger plants in Swansea, Wales, where a ready supply of cheap coal helped keep smelter treatment terms of the day low. These themes are eerily resonant of today where booming copper production in China has impacted the industry, and also where energy consumption, closely linked to today’s more familiar theme of ‘climate change’ remains an important challenge currently confronting the entire industry. The paper concludes with comments on these seemingly parallel situations today and offers some thoughts for the future.

Jan 1, 2009

Microstructural investigation has shown that grain splitting or deformation banding ( DB ) develops progressively with increasing strains during cold rolling. Of particular significance to simulating texture development in cold rolled BCC polycrystals is the operation of higher order slip systems other than 110 and, the occurrence of DB in the rolling plane since the latter allows a new relaxation of the shears. Deformation banding ( DB ) model includes grain subdivision in the rolling plane and applies the Relaxed Constraints ( RC ) mechanism for the other shears. An energy criterion for deciding whether deformation banding occurs or not has been postulated, referred to as Deformation Banding Criterion ( DBC ). This paper reports the results of the investigations into the effects of different slip systems, i.e., those based on 110, 112 and 123 slip planes and their combinations using RC, DB and DBC models, in developing simulated BCC rolling textures.

Jan 1, 1999

By Olli Hyvärinen

The capacity of Outokumpu Pori Copper Refinery has been increased by 50 % to 70 000 t/a in the last five years by adopting periodic current reversal, reducing spacing and installing some new cells in the old tank house building. Five years operation of PCR has proved that it is possible to achieve additional capacity with PCR and yet produce high quality cathodes. The impurity level in anodes has considerably increased, and recently, arsenic, antimony and sometimes bismuth have displaced nickel as the most critical impurity.

Jan 1, 1987

By Paula Ana Paiva

The high economic value and unique technological properties of the platinum-group metals (PGMs), plus their growing scarcity in the Earth’s crust, justify the crucial importance of developing recycling practices for PGMs end-of-life materials. Examples of top devices relying on the use of PGMs are automotive and industrial catalysts, and electrical and electronics equipment. This article critically describes the most recent research on the use of solvent extraction to recover one PGM, palladium, from spent catalysts. Some groups focus on the development of schemes involving commercial extractants, while others prefer to design specific molecules to efficiently and selectively recover palladium from these particular complex leaching solutions. Examples of commercial extractants proposed for the former schemes are Alamine® 308, TBP and LIX® 84I; while on the other hand, sulfur-containing diamides, thioamides, thiocarbamates, and dithioethers have recently been developed. Ionic liquids have to be mentioned too.

By J. R. Odekirk

The nature of mineral distributions and locking characteristics in mill products are important factors in understanding mill performance. Such data are obtained by microscopic point counting methods. Reduction 'of point-count data from volume to weight percentages, and reduction of data for each size fraction back to a head sample requires lengthy hand calculations. The use of computer processing for such data reduction results in obtaining information on a realistic time basis. An example of computer processed point-count data is presented.

Jan 1, 1981

By Jussi Vaamol

A commercial CFD-code was used to solve isothermal flow fields of gas and liquid in a Peirce-Smith converter. The model was validated with a 1/4 scale water model, and parametric study. Limits of the modeling technique used were recognized, but calculated results indicate that the present model predicts the general flow field with reasonable accuracy. The model was used to examine general flow conditions in an industrial scale PS-converter. Typical scaling factors of physical models were also evaluated with the aid of predicted bubble distribution, patterns of the flow fields and magnitude of flow velocities. The numerical simulations were found to open new viewpoints to the fluid dynamic related phenomena in the PS-process.

Jan 1, 1998

By A. E. M. Warner

In co Limited has long and extensive experience in converting nickel-copper primary smelting mattes over a broad range of nickel/copper weight ratios and combined nickel-copper-cobalt contents. At the Copper Cliff Smelter, the composition of the converter product matte has to meet the requirements of the matte separation process; at the Thompson Smelter, converter matte of a different composition is cast into anodes for nickel electrorefining; and in Soroako, Indonesia, a very low copper product matte is granulated for the Japanese market. Recently, Inco has conducted pilot plant testing of three possible nickel-copper matte continuous converting routes, namely flash converting, oxygen top blowing-nitrogen bottom stirring, and tuyere blowing. This test work has generated substantial new information on nickel-copper matte converting chemistry. This overview paper reviews the metallurgy of nickel-copper matte converting, in particular the behaviour of cobalt and the operating conditions required to meet the iron and sulfur specifications of the product matte. The relevant thermodynamic information is used to discuss the industrial data.

Jan 1, 2003

By G. Laird, N. B. Gray, N. Lawson

"Photographic, video, laser, hot film and conductivity methods are used in the experimental study of gas-liquid flows. A discussion of their capabilities and limitations are given in this paper illustrating the wide range of phenomena that can be studied. Most of these methods are limited to physical models at room temperature with transparent fluids, although they can be extended for use with opaque and hot fluids. A number of these techniques have been used by the GKW CRC in studies on industrial plants and their usage is increasing although a number of technical difficulties still need to be overcome. An in-depth discussion of the laser doppler anemometry (LDA) and particle image velocimetry (PIV) methods is given with experimental results on the flow field of an air plume in water based on advanced development of the techniques and studies carried out at the GKW CRC. The LDA method provides high resolution data on the velocity profiles, while the PIV method provides an overall view of the complex flow structure occurring at the gas-liquid regions. These two methods complement each other in providing experimental data for validating numerical models and exploring the complexities of multi phase flows.IntroductionThe injection of gases into melts is an important operation in the metallurgical industry. It is used in converters, anode furnaces, blast furnaces, ladles, bath smelters, zinc fumers and many other smelting processes. In many of these processes, the gas is injected into a molten bath resulting in the formation of bubbles that promote reaction, mixing, alloying and heat transfer. The study of gas-liquid systems presents enormous challenges to the researcher due to the complexity of the mathematical and physical modelling which require innovative numerical and experimental skills."

Jan 1, 1996

By Yasuo Ojima

The mainstream of copper smelting processes in the world today is a combination of Outokumpu type Flash smelting and PS (Pierse Smith) converting process. Presently it can be estimated that about 50% of the worldwide copper production is produced by the Flash smelting process and 80% by the PS converting process. PS converting process due to its operational flexibility and despite its batch character of operation has been widely used in many smelters for more than 100 years. However, an environmental issue has been pointed out related to this process because of the difficulty of handling the fugitive gases. Recently several copper smelters in the world have been newly construeted and others have executed major modification and modernization. The continuous converting process has been applied in many of them instead of PS converting process. This paper compares PS to the emerging continuous converting process and makes a prospect of the future of the copper converting process.

Jan 1, 2003

By W. J. Mitchell

During the months of April and May 1992, the Phelps Dodge Hidalgo smelter underwent a major turnaround. This was the third such turnaround in the life of the facility which was commissioned in 1976. During the third furnace campaign, the smelter processed 5.2 million tons of concentrate producing 2.6 billion pounds of anode copper over a 7.5 year period. The critical path on the fifty-nine (59) day turnaround schedule was the reconstruction of the Outokumpo flash furnace which integrated some modifications with standard rebuild practices. Modifications included incorporation of horizontal cooling jackets throughout the furnace settler as well as the installation of castable refractory in the reaction and uptake shafts.

Jan 1, 1993

By Katsumi Ogi, Hiroto Uchida, Masamitsu Sato, Atsushi Itsuki

"(BTMSE)Ag(hfac) (BTMSE = trans-bis(trimethylsilyl)ethene) was chosen as a suitable precursor for the XeCl laser (308nm) MOCVD of Ag. Iso-propanol solution of (BTMSE)Ag(hfac) was used as a liquid source for the liquid delivery method, high deposition rate 9nm/min at substrate temperatures of 100°C and 120°C were obtained at the vaporizer temperature of 90°C. This deposition rate is three times faster than by conventional bubbling method and life of the source and reproducibility of the deposition were also improved. Electric resistivities of the laser deposited film shows significantly low resistivity of 10-6Q-cm compared to 1 o-3Q-cm of thermal MOCVD film. These results indicates that the laser MOCVD is one of the effective method for the preparation of the high quality silver film.IntroductionSilver films are a potentially important metallization material in electronic and photonic devises due to their lowest resistivity (1.6µ0-cm) among the metals, high optical reflectance and chemical stability. The MOCVD technique has advantages to sputtering or evaporation in the point of conformal growth and better coverage on sharp steps and narrow gaps[l-2]. For MOCVD application, silver precursors must have sufficient vapor pressure without decomposition at their evaporation temperature. To achieve stable precursor gas supply, liquid delivery of precursor material is promising[3-4] especially for materials that have not enough heat stability and high vapor pressure like silver complexes[S-10]. Several new silver complexes for MOCVD and UV irradiation effect to their MOCVD silver film quality were reported by same authors[5]. In this paper new solvent system for liquid delivery system of silver MOCVD were investigated to suite XeCl(308nm) laser MOCVD application."

Jan 1, 1998