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By Moto Goto

Today, Pierce-Smith converters, coupled together with various types of smelting units, are used in most of the world's smelters. However, due to the "batch" processing nature, and problems associated with fugitive emissions during the transfer of melt and blowing stages, this arrangement will unlikely be adopted in future smelters. Modern day alternative processes include the Mitsubishi Process, Outokumpu Flash Smelting and Flash Converting Process, the Noranda Process, and the Ausmelt Process, but only the Mitsubishi Process is a "truly continuous" smelting and converting operation, producing a constant flow of blister without tapping, and is economically proven by long term commercial operations. This paper reviews recent advances in modern continuous converting technologies, with a special section devoted to operation of the "first standalone Mitsubishi C-furnace" coupled together with a Noranda Reactor, at Port Kembla Copper Pty. Ltd. in Australia.

Jan 1, 2003

By Michael F. Kitto

The production of sulphuric acid at base metals smelters is predominantly an involuntary activity and now comprises approximately 17% of all-forms sulphur supply in world terms. The majority of elemental sulphur is also produced involuntarily in response to environmental regulations regarding emissions from hydrocarbon processing plants. The paper examines the points of similarity and difference in the sulphur and smelter acid markets, and reviews their interactions. The reasons for the merchant acid market collapse of 1993 are analyzed, and the prospects of a recurrence are considered.

Jan 1, 1996

By W. C. Hellyer

The papers in this section provide several examples of the application of Process Mineralogy to metallurgical problems. Any experienced metallurgist could cite numerous other examples when process mineralogy has, or could have, provided data of value in his understanding of metallurgical processes. The data developed by mineralogic techniques may supplement conventional chemical analyses, but cannot be replaced by assays. Mineralogic and chemical analyses each provide different types of information. In order for the process mineralogist to interpret his results in the most useful manner, it is desirable that he should have some knowledge of metallurgical processes. Conversely, the metallurgist should have some knowledge of mineralogic techniques to understand the scope and limitations. Mineralogic examinations are time-consuming and expensive. To ensure the effort is not wasted, and indeed does not generate misleading information, the utmost care must be taken at every stage of sampling and sample preparation. The mineralogist may examine microscopically or by x-ray diffraction a one-gram sample representing a flow of possibly thousands of tons per day through a concentrator. Conditions in a concentrator change continually in response to changes in feed rate, feed characteristics, grind, reagent additions, temperature, circulating loads, etc. Lengthy sampling periods are required to ensure the samples examined are representative of average conditions. The sampling program should be drawn up jointly by the metallurgist and mineralogist. Sampling points should be selected with a view to ease of sample cutting. The sampler should be instructed in the method of cutting the samples, the weight or volume of sample to be taken at each cut, the sampling frequency, and sampling period. The sampling period required depends on the scope of the investigation. For example, if a complete survey is to be made of all final and intermediate products of a flotation concentrator, samples should be cut at not more than two-hour intervals, twenty-four hours per day, for not less than one week. For a more limited investigation of one circuit or one section of a concentrator, 'the sampling frequency could be increased to every hour and the sampling period reduced to one or two days.

Jan 1, 1981

By Tim Robinson, Michael S. Moats, Masatsugu Moritmitsu, Kathryn C. Sole, Lauri Palmu, Frank K. Crundwell

"Process technology and design trends for copper, zinc, and nickel electrowinning cellhouses include focusing on energy reduction, productivity, and acid mist abatement. Larger electrodes, longer cells, automation, and higher current densities are leading to more capital-effective designs. The latest cellhouse designs include installation of automated electrode-handling systems, thereby removing more operators from the cellhouse. These technology and design trends result in lower electrowinning operating costs and improved purity of electro won cathode.INTRODUCTIONTechnology transfer between similar industries is an important process in improving product quality and productivity, and reducing operating costs. The electrowinning (EW) recovery of base metals, such as zinc, copper and nickel, is no different. The zinc industry with its larger EW product-handling requirements as compared to nickel and copper, has been driven to automation technology and the use of larger equipment. This technology has been transferred to copper. Nickel has led development and application in large-scale anode and divided-cell technologies but, due to nickel being produced in multiple forms (not just cathode) and being a small part of the whole complex nickel process route, the quantities of electrowon nickel are small compared to copper and zinc. Copper process technology in acid mist abatement was recently transferred to nickel. The focus in copper EW has been on energy reduction and productivity."

Jan 1, 2012

By Thomas Frost

In this time of market globalization, many industrial companies are including detailed arbitration clauses in their international contracts, in order to avoid the potential costs, delays, and uncertainties of litigation in foreign courts. Arbitration is less expensive and more flexible, procedurally, than court proceedings, and arbitral awards enjoy much greater international recognition than judgments of national courts. More than 134 countries have signed the 1958 United Nations Convention on the Recognition and Enforcement of Foreign Arbitral Awards, known as the "New York Convention", which facilitates the enforcement of arbitral awards internationally. There are several other similar arbitration conventions that provide for the enforcement of cross-border arbitral awards. Additionally, arbitral awards are not subject to appeal, whereas judgments of national courts are routinely subjected to a lengthy appeals process, and there are very few viable bases to challenge arbitral awards. This discussion will review key considerations in drafting arbitration clauses, including choice of law and choice of forum considerations; issues surrounding the selection of arbitrators; the discovery process; presentation of evidence; and enforcement of arbitral awards.

Jan 1, 2006

By Hanlu Xie, Liang Yu, Ping Wang, Yuanchi Dong

"The leaching process is the first step when recycling BF slag as raw material for some other products. While studying the kinetics of the BF slag leaching process, a fractal phenomenon was found, which indicated some interesting mechanism in the process. The result suggested a new understanding of the leaching process in detail which useful for the industrial applicationIntroductionTypical composition (wt. %) of blast furnace slag varied in a pretty wide range: SiO2 30–40, Al2O3 10–20, CaO 30–40, MgO 5–10.The ground granulated slag is commonly used as base of roadway (mixed with natural inert for paving, soil stabilization, etc.) or one of the resources of Portland cements because of its good hydraulic activity [1]. To recycle the slag economically, the selective recovery of some components of the slag may be considered. As main components exist in the slag, silica [2, 3 and 4] and alumina [4] recovery was first considered.While recovering of silica from the slag, silica gels are recovered selectively from the leaching solution deriving from the treatment of the slag with waste sulfuric acid. After separation of the exhausted solid of leaching, the silica gel is precipitated from the solution at pH 3.2. Although the silica gels obtained by this procedure contain many impurities and need some more work afterward, it is the first and important step for the process.In the prior work [5], silica extraction using blast furnace slag had been investigated, focused on the pH value of selectively silica extraction. In the present work, kinetics of the leaching process was focused. It is important to design an economical process.ExperimentalThe composition of the slag and the calcined gels has been determined by a LINK860 (Oxford Instruments, Oak Ridge, TN) energy dispersive spectrometer (EDS) in conjunction with a CAMBRIDGE S250-M2 (Cambridge Instrument Ltd., Cambridge, U.K.) scanning electron microscope(SEM). The leaching of slag and the precipitation of silica gels have been conducted at atmospheric pressure in a stirred reactor placed at temperature controlled by a heated water bath."

Jan 1, 2008

By Halvor Dalaker, Alain Marc Ferber, Thor Anders Aarhaug, Pål Tetlie

Off-gas monitoring of experimental reactors give little information about intermediate reaction products and reflect chemical equilibria at reduced gas temperatures. A reactor design with optical access was designed and tested in order to be able to qualify and quantify gaseous species from their emission spectra. By use of a sequence of sapphire, UV fused silica and IR transparent sapphire and CaF2 windows and lenses optical access to a hot, maximum 1800 °C, reaction zone was gained. A cooled area behind the reaction zone was used as a background in order to avoid signal saturation from reactor walls. In addition to molecular emission spectra, atomic emission lines are used to characterize stable gas constituents and radicals. The setup has been designed for the study of methane dehydrogenation experiments in order to investigate the carbon activity of reduction of oxide with methane, but has also been used to monitor gaseous silicon suboxide.

Jan 1, 2015

By R. D. Prengaman

Lead usage in paint, anti-knock gasoline additives, pipes, seals, and solder has declined markedly over the past 30 years. Products utilizing the unique properties of lead and its ability to be recycled have survived and grown. These products include shielding, glass (particularly TV and computer screens), sheet for roofing, stabilizers for PVC, insoluble anodes for metal production, electronic solders and lead acid batteries. With the loss of markets many companies have decreased lead product development efforts. Much of the patent lead materials development is devoted to lead acid batteries. In the past 25 years, the automobile battery has been almost doubled in power and reduced in weight, leading to a nearly three-fold increase in performance. Corrosion-resistant lead alloys and improved battery designs have made battery lead usage more efficient. The same corrosion-resistant battery alloys are utilized to increase the life of electrowinning anodes. The challenge for lead product development is not only to maintain and improve the existing lead products, but also to develop the growing lead acid battery market for telecommunications, uninterruptive power sources, remote area power, hybrid and electric vehicles. Lead

Jan 1, 2000

By Hongmin Zhu, Guihua Wang, Xiangsheng Wang

"The anode process of carbon electrode in fluoride melt was studied by voltammetry and chronoamperometry. Anode gases were analyzed by gas chromatography on-line during controlled-potential electrolysis. Two peaks were observed on the cyclic voltammograms. According to the results of gas chromatography, the first peak was corresponded to the discharge of residual oxide ions, with the formation of CO and CO2. Discharge of fluoride ions occurred at 4.1 V vs. Li+/Li, and leading to the anode effect. With the occurrence of anode effect, small amount of CF4 was detected. As the potential reached 4.5 V, CF4 and C2F6 gas evolution occurred, and the current increased to form the second peak.1.IntroductionIn the primary production of Aluminum and some rare earth metals like neodymium, a departure from normal cell operation known as anode effect results in the generation of perfluorocarbons (PFCs), which have high global warming potentials [1]. Owing to the pressure of environmental protection, considerable research has been carried out to clarify the mechanism of anode effect and PFC generation of industry and laboratory cells in the aluminum electrolysis system [2-9]. The common result on PFC generation is that the PFCs are emitted from Hall-Heroult cells only when they are on anode effect. In this article, we selected LiF, the main electrolyte for the neodymium electrolysis [10-11], to perform further investigation on the underlying kinetics of PFC generation and the nature of the reactions at the electrode.2. ExperimentalAll experiments were carried out in an alumina tube reactor, which was filled with high purity helium atmosphere. Spectrographic graphite crucibles were used, which played the dual role of molten fluoride container and the counter electrode. Lithium fluoride was analytical grade. The experiments were carried out at 900 °C."

Jan 1, 2011

By J. W. Matousek

In the flash smelting of copper sulfide concentrates, the course of reactions from the burner tip, through flame "burn-out" (the point of oxygen depletion), to settled matte and slag is of particular interest in understanding the mechanisms of the process. Numerous reaction sets can be proposed to describe the chemical changes that might be taking place, but from outside the furnace no one set offers an obvious advantage in explaining the actual processes involved. Only a combination of mathematical modeling and flame and bath sampling can achieve this result. This paper shows that flash smelting, while still reasonably orderly, is a more complex process than suggested by the technical literature.

Jan 1, 1993

By H. Cepin

Production of non-ferrous metals is still principally performed in shaft and flame fired furnaces. Electric furnaces increase metal recovery, reduce environmental burdens and decrease energy consumption compared to conventional processes. Because non-ferrous metals have low melting and boiling points and aggressive slags design of the furnace, energy input, and slag conductivity and composition are very important. Secondary materials are easily handled in electric furnaces. Since additional amounts of lead, zinc and tin will become available from secondary sources in the future, electric furnaces are expected to replace conventional smelting furnaces. The paper describes technical, electrical, and process designs of electric furnaces peculiar to the reduction of non-ferrous metals. Electric and various thermic furnace processes are compared.

Jan 1, 1990

By J. K. Brimacombe

"Nearly all the easy things have been investigated in injection metallurgy. Water models have been used exhaustively to study mixing, gas distribution and flow in submerged jets. Mathematical models have been developed with their restrictive boundary conditions to quantify submerged gas jet behavior. While being valuable tools to our understanding of injection metallurgy, there is an obliqueness to their application. What we need now are measurements and modelling on the actual systems, hot and unfriendly, where gas meets liquid at temperatures above l000°C. This is where the challenge lies.AN APPRECIATONThere are those who follow the trail and there are those few who blaze new trails in search of novel concepts and processes. With his restless, inventive mind, Howard Womer is a trail blazer without doubt. Decades ago, he was a pioneer in the pursuit of continuous steelmaking with the WORCRA Process and, today, he is developing new processes for the treatment of waste. He is not only an inventor but has been a professor at the University of Melbourne and was the first Director of Research at BHP. He has influenced the lives of many people, including myself; with his achievements and humanity. Therefore it is most fitting that this symposium should be held in honour of Howard Womer, a luminary in the metallurgical world for over half a century.BACKGROUNDGas injection has been an integral part of pyrometallurgical processes since the early days of Bessemer, then of Pierce and Smith. Today, of course, one cannot imagine pyrometallurgical processes without submerged gas injection to effect reactions for metal extraction and refining, to provide mixing and to inject solids into molten metal, slag or matte. Spurred on by new developments like tonnage oxygen and argon production, the Savard-Lee concentric tuyere and porous plugs, new steelmaking processes have emerged; and now solids injection is changing copper extraction processes. The ingenuity of the extractive metallurgists who drove these developments is inspiring for they have applied gas injection to transform pyrometallurgical processes. Humankind has been the beneficiary.' Today these processes are safer, more efficient, cost effective, less energy intensive and more environmentally friendly."

Jan 1, 1996

By H. Kamarudin

The behaviour of cassiterite-sulphosuccinamate flotation system was examined in the light of zeta potentials measured by micro-electrophoresis method. It was observed that sulphosuccinamate substantially affects the zeta potentials of cassiterite, lowering its i.e.p. to pH 2.5 and indicating a specific adsorption and/or chemical interaction. The optimum concentration for flotation, as seen in micro-flotation tests, was found to be associated with the most effective lowering of the zeta potentials, the optimum pH being 3.0. The effect of cations in the pulp was examined for the presence of ferrous, ferric, aluminium and lead ions. The ions ferric and aluminium were observed to create an intense effect of increasing the potentials to positive side, possibly due to adsorption of cation hydroxy complexes, as indicated by their respective species distribution diagrams.

Jan 1, 1994

By Nils Lippmann, Ulrich Weber, Siegfried Schmauder, Jr. Mishnaevsky

"A computational approach to the optimization of fracture resistance of multiphase materials (here - high speed steels) by varying their microstructure is presented. The main points of the optimization of steels are as follows: (1) development and verification of the model: numerical simulation of crack initiation and growth in real microstructures of steels, (2) computational experiment: simulation of crack growth in different idealized quasi-real microstructures and (3) the comparison of fracture resistances of different microstructures and the development of recommendations to the improvement of the fracture toughness of steels. Numerical simulations of crack growth in real microstructures of steels and different idealized carbide distributions are carried out. On the basis of the simulations, recommendations for the improvement of high speed steel microstructures are given. It is shown that the fracture resistance of the steels is much higher for the fine than for the coarse version of the same type of microstructures.IntroductionThe purpose of this work is to develop an approach to the optimal design of multiphase materials on the basis of numerical simulation of their behaviour under mechanical loading. We suggest here the following strategy:1. Collecting input data for the simulations: taking a micrograph of a microstructure, and determining mechanical properties and failure conditions of the material constituents [1, 2],2. Simulation techniques and assumptions are tested for a real microstructure of the material: crack growth in a real microstructure is simulated and then compared with the experimental data,3. Computational experiments: different microstructures of materials are tested in the numerical model under the same loading conditions. The calculated service properties of the different microstructures are compared, and recommendations are developed. As differentiated from the ""real"" experimental techniques, the computational experiment is much cheaper and not labor- and time-consuming."

Jan 1, 2001

"Injection technology has been an important subject from the early days of ladle metallurgy until the present. During the last decade, there have not been many publications in the area of injection technology. It is the author's opinion that with the challenge to find new solutions especially to environmental and energy related problems as well as better understanding of phenomenas from computer modelling, a new era of inventive injection technology developments is at hand. This is illustrated in the article with examples from six different areas where MEFOS is or have recently carried out R&D work related to issues from the injection technology field. IntroductionThe boom in injection technologies came with the introduction of ladle metallurgy treatment during the '70s and '80s. Since then, the theories and principles have been thoroughly laid down by a number of scientists and also published at several early SCANINJECT conferences.Not many new technologies/applications have been presented during the last ten years. This might lead one to believe that everything is known and done. Those, like MEFOS, who are challenged to find technological solutions to a number of environmental problems and energy saving issues in the pyrometallurgical field are, however, continuously faced with the task of developing new injection technologies.Especially, the call for sustainable technologies to solve environmental problems is a challenge for metallurgists all over the world and it will surely induce a revival of injection technologies. So, in order to encourage all injection experts, let us share some new experiences and let us encourage each other's creativity to solve some of the demands of the future society.The following show some examples of technologies under development, or recently tested."

Jan 1, 1996

By S. K. Kawatra

A growing concern for pyrometallurgical operations is the generation of airborne particulates. These particulates can be generated by combustion processes, or by materials handling. Regulation of these particles by the EPA has become progressively more stringent, first for particulates finer than 10 micrometers (PM10), which are particles fine enough to be inhaled into the lungs. Then, restrictions were introduced on emissions of particles finer than 2.5 micrometers (PM2.5), which are fine enough to become embedded in lung tissues. The next stage of regulations is likely to be ?nanoparticulates,? particles finer than 100 nanometers, which are in a size range where their very high surface area leads to enhanced reactivity. While all of the health effects due to nanoparticulates have not yet been determined, there have been enough studies to indicate that there is a problem, and restrictions on nanoparticulate emissions are only a matter of time. In this paper, it will be demonstrated that dry handling, comminution, and combustion sources represent a significant concern for both PM and nanoparticulate emissions. In regards to dry handling, the effects of utilizing effective dust suppressants on PM and nanoparticulate emissions will be explored.

Jan 1, 2006

By P. Wieser, D. Feke

"Priming of filters with small pores is influenced by the surface tension of the liquid metal and may be complicated by freezing • Freezing followed by melting has been observed experimentally. This process has been modeled on the basis of one dimensional heat flow by radiation to the filter and by conduction in the metal. Also considered are super-heat of the metal and the initial filter temperature. The results of the model provide useful guidelines for the application of filters. IntroductionFiltration has been recognized as a valuable method of refining by removing suspended phases from liquid metals or alloys. Woven fiberglass type fabrics and wire screens were used initially in the aluminum industry. With the introduction of the ceramic filters that exhibit improved inertness and refractoryness, filtration has been introduced to higher melting alloys including cast irons, superalloys, stainless steels, as well as low and medium carbon low alloy steels. A considerable literature is delveloping rapidly on the progress in applications and the advances in understanding the mechanisms and effectiveness of filtration processes (1-8).With the use of filtration for different alloy systems for the production of cast to shape parts a bewildering variety of gating system modifications has been developed (Figure 1) to accommodate the installation of filters in the mold. The modifications have two principal purposes: 1) the runner expansion is intended to compensate for the resistance to flow due to the filter and that of the captured inclusions, and 2) the metal reservoir upstream of the filter, provides a temporary by-pass which permits metal to flow across the filter and heat it until priming can be accomplished. priming of.filters by low and medium carbon steel is readily accomplished but, compared to such alloys as cast iron or 19 Cr-9Ni stainless steel, requires greater precautions to avoid failure to prime by excessive freezing on or inside the filter pores. This problem is further examined below:"

Jan 1, 1986

By Brian R. Green

Resin-in-pulp (RIP) technology has been developed for recovery of gold. It is now time to look forward to the potential for application of the technology to other situations. Some cases have been identified and have merited preliminary testwork. Four examples, which illustrate the potential of RIP, are dealt with in this paper. These include removal of metal-cyanides from pulps, recovery of manganese that is difficult to wash from filter cakes, recovery of nickel from low grade pulps, and recovery of zinc from process residues. The discussion includes descriptions of the problems, factors that affect the choice of resin, and factors that will affect the economics of the process.

Jan 1, 1998

By D. A. Meyn, R. L. Holtz, C. S. Pande, M. A. Imam, D. J. Singh

"Various theoretical and experimental techniques used to search and develop new metal hydride systems suitable for hydrogen storage are described. The main theoretical technique under study makes the use of electronic structure of the candidate materials. Microstructural characterization techniques like transmission electron microscopy are being used to study the hydride formation. Novel processing techniques for material preparation such as those needed to produce thin films or amorphous phases are also being utilized. The techniques are illustrated with results from Pd, FeTi and Mg2Ni systems.IntroductionOf the four methods of hydrogen storage, compressed gas, cryogenic liquid, metal hydrides, and gas-solid adsorption, the metal hydride storage method is more attractive from the point of view of high volumetric density and safety. Compressed gas storage has disadvantages of extreme pressure, weight, and volume requirements, whereas storage of hydrogen as cryogenic liquid is unattractive due to the requirements of extremely low temperatures and high consumption of primary energy. Moreover, the number hydrogen atoms present in a volume of 10- 22 Cm3 (nH) in liquid hydrogen state (- 20K) is 4.2 whereas number of hydrogen atoms that can be accommodated in a free volume of 10-22 cm3 of various hydrides are as follows: LiH--5.9, TiH2--9.2, ZrH2--9.2, VH2--l0.2. High hydrogen concentration is usually associated with a large H/Metal atomic ratio but is also a function of structure."

Jan 1, 1994

By Robert B. Haagensen

While light optical microscopy has long been employed by the mineral processing industry, there has been a tendency to shy away from its use for all but the most exacting purposes. Despite the usefulness of micros-copy in solving a wide variety of problems, the response to such work is often less than enthusiastic primarily due to time considerations. Microscopical techniques are therefore often relegated to the "ivory tower" and their direct and practical application to everyday problem solving over-looked. The purpose of this paper is to dispel such attitudes and promote a wider use of light microscopy. Several examples are given which point out the indispensib1e nature of optical microscopy as a rapid means of defining and solving problems in mineral processing. The application of other instrumental techniques to augment the information obtained is also discussed, particularly the value of the combined use of the optical microscope and electron probe micro-analyzer.

Jan 1, 1981