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By A. A. Bustos

Four Air Liquide Shrouded Injectors (ALSI ) were installed and operated for over one year in a Peirce-Smith converter at the Falconbridge nickel smelter in Falconbridge, Ontario, Canada. A shrouded injector consists of an inner pipe and an annulus, through which high oxygen enriched air and nitrogen flow, respectively The nitrogen cools the injector and protects the refractory in the vicinity of the injector tip, allowing for substantial increases in oxygen flow rates to the converting reactions. Several injector designs were tested to study the effect of changes in the cross-sectional area and changes in the entrance geometry of the annulus. An optimum design would minimize the injection pressure required for a given flow rate to achieve choked flow conditions at the tip of the injector. The operation of the ALSI was simple and did not require any special care or maintenance, either between blows or between converter cycles. In particular, the shrouded injectors did not require punching, as is the case with conventional tuyeres. In terms of refractory performance, the ALSI, operating at 30-40 % oxygen enrichment, were superior or equal to the conventional tuyeres, which operated at 21-23% oxygen. The results of the demonstration program led Falconbridge Limited to implement the ALSI technology on a commercial scale The paper presents the demonstration program results in terms of gas flow rates, accretion formation, punchless operation and refractory wear.

Jan 1, 1999

By Merete Tangstad, Ragnar Tronstad

Ferromanganese production in electrical furnaces is quite an old process. However, as the furnaces are getting bigger, the requirements of cost, yield, product quality, emissions and security are raised. With the increased expectations, the fundamental knowledge must follow. Within the last 25 years there has been a great effort both in the industry as well as the academic environment to push the limits of this process. This article will show some examples of improvements within fundamental data, reaction mechanisms and emissions over this time period.

Jan 1, 2014

By James D. Navratil

Ferrites have been used to separate a wide range of substances such as dissolved metal species, particulate matter, and organic and biological materials; they have been used almost exclusively for metal waste treatment applications. The versatility of the ferrite waste treatment technique is evident in the wide variety of application methods. Furthermore, ferrites can be used to remove selected impurities in feed solutions containing metal products requiring purification. A brief overview of ferrite properties and recent applications for metal recovery and waste processing will be presented.

Jan 1, 1990

By Maria das Graças da Silva Valenzuela, Guillermo Ruperto Martin Cortes, Francisco Rolando Valenzuela-Diaz

Bentonites are an important kind of industrial clays with more than a hundred different uses. In the oil and gas industries they are used as thixotropic additives for drilling fluids and also as sorbents for purification of flows and effluents. Due to the mechanical and thermal properties that they exhibit, bentonites will become in a near future important fillers in clay/polymer nanocomposites which could be used in the oil and gas industry for replacement of various metal components. In this paper a chocolate color bentonite from the state of Paraiba in Brazil was characterized by diverse techniques such as XRD, DSC/TGA, surface area, and cation exchange capacity and it was studied its potential use as thixotropic additive for oil and gas drilling fluids and assorbents of oils. The bentonite showed good potential for use in those applications.

Mar 1, 2018

By Mingsheng He, Yunhui Tang

The structure and granularity of biological origin aragonite from abalone shell during wet grinding in a ball mill were studied with X-ray diffractometer, with morphology studied by scanning electron microscope (SEM). It is shown from the results that the particle sizes of aragonite decreased with grinding time, so did the X-ray diffraction (XRD) peak intensities, while the full widths at half maximum increased. A calcite XRD peak with low intensity and great width was observed in nearly all the samples with various grinding time, whereas the intensity of the peak increased obviously after grinding time 300 min. It is shown from the SEM results that the size of aragonite dropped with grinding time until it reached 20 nm and then kept constant, while that of calcite dropped first and then rose at the minimum about 10 nm until to the constant size as in aragonite. It was observed that the mineral content obtained from XRD show an obviously change that the calcite increases while aragonite decreases, which indicated the occurring of a polymorphic transformation of aragonite into calcite.

Mar 1, 2017

By Leonel Contreras

The gas treatment system, MALIGAS (in Spanish MAnejo y Llmpieza de GASes which means handling and cleaning of gas), is part of the Codelco-Chile Potrerillos Smelter decontamination plan; which includes the newly designed system for the cooling and cleaning of the gas generated from a Teniente Converter and four Peirce Smith Converters. The gas generated in the process is captured by water cooled hoods and mixed with air. Then the gas enters a cooling pre-chamber which utilizes a water cooled screen to capture and remove the coarse and semi-fused particles. At this stage; the gas loses a portion of its heat with temperature falling below 608°C which is a necessary condition to avoid damage to the pipes, ducts and other metallic structure of the gas handling system. The gas is further cooled at the Radiation Cooler to a temperature ranging between 315 and 380°C. The gas is conditioned to avoid damage to the electrostatic precipitators that are designed to clean the gas by removing significant amount of dusts from the: gas stream. This gas stream is currently discharged to the stack, however, it will be treated in a sulfuric acid plant that is currently under construction and is scheduled for commissioning during the second half of 1999. The gas handing and cleaning system has been operated without any significant interruptions. Minimal emissions of SO2 and dusts in the work place are noted. The system requires minimum maintenance. The key to the high availability of the system is due to the good, performance of he Radiation Cooler, which efficiently cools the gas before entering the electrostatic precipitators (ESPs). This enables the ESPs to remove the dusts efficiently.

Jan 1, 1999

Bath smelting options for recovering valuable metals from jarositic residues containing 22-28% lead and 16-30% sulphur obtained from pressure leaching zinc-lead-copper bulk concentrates were investigated using thermochemical computations and crucible-scale experiments. Direct fuming of lead and zinc from a slaglmatte bath at 1250-300°C was demonstrated successfully. Up to 93% of the lead was recovered in the fume and steady-state recoveries of zinc were predicted in the range 82-95% under these conditions. The energy required for the fuming reactions was supplied by partial combustion of the fuel, added as char, with air. An important feature of the process is that the recoveries to the fume are not significantly affected by changing: the fuel:air ratio over a wide range. Thermodynamic computations, confirmed by experimental results also showed that the presence of a matte phase is not essential for high recovery of lead and zinc to the fume. Operating conditions which produced a matte ensured that about 70% of the silver and 80-90% of the copper were recovered into that phase. Approximately 98% of the arsenic in the residue was fumed. In the absence of matte the slags contained high arsenic levels (260-330 ppm) but low arsenic (20-60 ppm) levels were achieved when matte was produced.

Jan 1, 1994

By Satoshi Yamashita, Noboru Masuko

"Newly prepared bipolar membrane is promising to become a key material of an electrolyser for a production process of strong reducing solvent. This research is basic research for using bipolar membranes as electrolysers of reducing agents, Cr(II), TI(III) and V (II) on the laboratory scale. In this report, a bipolar membrane was tried with an electrolyser, reducing chromic chloride to chromous chloride. An analysis of mass balance demonstrates advantages of it over the former electrolyser equipped with an anion and/or. cation exchange membrane. The effects of current density and concentration of Cr(lll) on the reduction rate of Cr(II) and the current efficiency were examined No deterioration of the bipolar membrane resulted from the electrolytic reduction of Cr(III). IntroductionRecently, bipolar membrane that was the development subject for a long time in the industry of ion exchange membranes has met the stage of the practical application at last [l]. The expectation of the application to the hydrometallurgy field increases. We took up the manufacturing of the strong reducibility solvent as part of the application of bipolar membrane to hydrometallurgy technology. This laboratory has much experience in the electrolytic reduction of Cr (II) aqueous .solution such as chromous sulfateusing bipolar membrane were compared in theory to chromous chloride aqueous solution manufacturing of the strong reducibility solvent. The advantage of applying bipolar membrane by substituting ion exchange membrane is described, and the experimental result is reported."

Jan 1, 2000

By Neil Rowlands

Particle liberation studies are commonly used in the determination of the proportion of locked and liberated phases in ground ores at various stages of mineral processing. These studies may range from a qualitative assessment of a polished specimen in an optical microscope to a full quantitative analysis of the liberation characteristics of fine grained complex sulfide ores using scanning electron microscopy and high level image analysis. However, the conversion of quantitative data to meaningful information on a mill operations level is by no means a simple task. This paper reviews the errors inherent in the SEM/Image Analysis technique and looks at the various methods available to minimize errors in data collection.

Jan 1, 1992

By P. H. Scaife

The pyrometallurgy industry faces a series of environmental challenges, based on local, national and global issues. While local impacts continue to be important, national and global concerns with Sustainable Development, Greenhouse emissions, Acid Rain and water resources are key strategic drivers for the industry. The environmental problems of the industry are well known: emissions of sulphur dioxides and carbon dioxide, disposal of arsenic wastes, consumption of fresh water, fate and impact of minor components/trace elements in raw materials (whether conventional or complex, or wastes). Solutions to these problems require the application of Cleaner Production principles (waste minimisation, energy conservation, product design to enable ease of post consumer recycling), new technology and scientific studies to assess impacts of discharges. A number of opportunities, driven by environmental concerns, have also been identified

Jan 1, 1994

By David J. Kinneberg, Barbara E. Mangion, Arnold M. Savolainen

Analytical laboratories require a qualitative or semi-qualitative method of determining major and minor constituents in "unknown" samples to select optimal analytical techniques. This is exceedingly important in precious metal assay laboratories where the precision and accuracy requirements are exacting (routinely within 0.02%, absolute basis). This paper describes the use of an x-ray fluorescence spectrometer with a specially designed software package to select optimal analytical procedures and specify relevant analytical parameters. A wavelength dispersive XRF spectrometer is capable of quick and accurate analyses of properly prepared samples without extensive standardization. When coupled with a specially designed software package, this preliminary assay system is applicable to a wide variety of sample types including gold and silver bullion, karat gold and karat PGM alloys, high silver and high copper metallic samples as well as particulate samples of ores and sweeps. The system relieves the assayer of tedious calculations for silver inquartation and proofing, minimizes human error and standardizes selections over time. Most importantly, the system allows for independent verification of final assay results.

Jan 1, 1999

By J. P. Downey, T. Salisbury, M. Berlin, E. Rosenberg, G. Pinson, R. Christianson, K. Gleason, W. Gleason, S. Davis

"The Center for Advanced Mineral and Metallurgical Processing is developing membrane production technology based on autocatalytic reduction of palladium from solution onto a unique, porous substrate. Surface membranes and catalytic structures are critically important to applications that range from hydrogen purification membranes to petroleum refining. Autocatalytic reduction processes represent a cost effective method of producing stable surface layered structures that have good working lives. These attributes are particularly important in the production of palladium alloy purification membranes used in hydrogen production. Although considerable research has investigated the interaction of hydrogen and palladium alloys, the mechanisms in play while the membranes form are not well understood. Preliminary research has identified three distinct deposition mechanisms and it appears that substantial control over the resulting membrane is possible.IntroductionPalladium-based membranes separate hydrogen from other gases because hydrogen is uniquely soluble in and readily passes through bulk palladium. As currently produced, palladium-based membranes are expensive and have short service lives. These circumstances are due in part to the lack of a complete understanding of palladium or palladium alloy deposition. The Center for Advanced Mineral and Metallurgical Processes (CAMP), in collaboration with the Metallurgical and Materials Engineering Department at Montana Tech and the Chemistry Department at the University of Montana, is engaged in the development of new methods and materials for hydrogen purification membrane production.In membrane production, the palladium requirement depends on substrate surface properties such as surface chemistry, porosity, and roughness. Thin, defect-free membranes have been successfully produced on substrates of porous glass, alumina, and stainless steel. However, the differences in the thermal expansion coefficients of palladium membranes and porous glass or alumina substrates cause problems at operating temperatures. The use of stainless steel substrates is advantageous because stainless steels have thermal expansion coefficients similar to that of palladium and they are stable at the required operating temperatures (Wicke, E., Brodowsky, H. and Ziichner, H. ). Stainless steel is also readily available and relatively inexpensive."

Jan 1, 2012

By Heinz Giegerich

This paper deals with a new development in recycling second generation catalytic converters, namely metal substrate converters (MSC). It describes a patented dismantling process, whereby the MSC is segregated into it's three components outer steel shell, metal substrate carrier foil and ceramic W8shcoat with embedded precious metals.

Jan 1, 1995

By Georgina De Micco

The National Commission of Atomic Energy is investigating a suitable physicochemical process for the conditioning of spent nuclear fuel and treatment of the scrap of research reactors of the Al-UxSiy type. A possible way of processing is through dry chlorination of the cladding with the purpose of selective separation of the aluminium from the remaining elements such as Fe, Ni, Zn, Cu, etc. transforming them into volatile chlorides. Some important advantages of this method are the thermal stability of the chlorides that allow the easy separation of the halides by physical methods and the low volume of radioactive waste generated. The interactions in the following systems were studied in the range of temperature between 150º-500°C: Al-Fe, Al-Ni, Al-Cu, Al-Zn, Cu-Zn and the pure metals. We found that the reactivity was different depending on if the elements were alloyed or separated. The separation factors of the systems under study were determined. Nickel is perfectly separated from aluminium for all temperatures, whereas good conditions for copper separation were achieved below 400ºC. In the case of iron, complete isolation was never attained. However, by decreasing temperature to 150ºC it is possible to obtain aluminium chloride with less iron content. The separation of zinc from the product was also difficult. It was detected that zinc chloride volatilization decreases when other chlorides were present, for example cooper chlorides. In the Cu-Zn alloy, zinc chlorides remained in the condensed product due to interactions with copper. The samples were characterized by scanning- electron microscopy (SEM), X ray diffraction (XRD) and atomic absorption.

Jan 1, 2006

By Guray Kaya

Boron minerals are widely employed in various fields such as ceramic, glass, cement, metallurgy, etc. Although boron deposits of the world are limited, the production level of boron-based products is continuously increased. Turkiye possesses approximately 73 % of total world boron resources. Etibor Kirka Borax Company of Turkiye produces tincal concentrates and borax pentahydrates. During such productions considerable amounts of concentration and derivation wastes appear. Having considered the increased rate of production it is quite obvious that the level of relevant wastes will also be raised. With this study it was aimed to utilize these wastes in roof tile and brick bodies and to convert them into a form environmentally and human friendly. Newly produced products were undergone to several standard tests for the determination of their shrinkage, water absorption, strength values and coloring parameters. Additionally, micro structural studies were conducted.

Jan 1, 2006

By Ann M. Hagni

Electric arc furnace (EAF) dust from the secondary steel industry contains lead, cadmium, and chromium that causes it to be classified as a hazardous waste. Pyrometallurgical treatment of EAF dust is directed at recovering zinc and simultaneously rendering the dust non-hazardous. The mineralogy of the EAF dust is important in determining the occurrence and phase relationships of the zinc, lead, cadmium, and chromium contents. The principle phases in EAF dust as determined by reflected light microscopy, SEM-EDS, and XRD are solid solutions of the iron spinels (franklinite, magnetite, and jacobsite), zincite, hematite, and Ca-Fe-Si glass. Chromium is present in small amounts in solid solution in the spinels. Cyclone sizing of the minus 53 pm particles shows that more than 50% of this size fraction are less than 10 pm in diameter. The <I0 pm particles contain zinc as both franklinite in solid solution with magnetite and jacobsite, and zincite as determined by transmission electron microscopy and XRD. Auger electron spectroscopy did not detect coatings of volatile phases on the surfaces of EAF dust particles.

Jan 1, 1994

By Robert D. Boiler, Bill Wilkie

"There is a wide choice of different types of woven filter media for hundreds of different filtration applications. Factors such as type of fiber, synthetic polymers used, weave style, fabric finishes and fabrication techniques all play an important part in selecting the best choice for a specific type of filter and process application. The purpose of this paper is to offer some basic knowledge of these factors and how they can impact the performance of a filter, the life of the media and the overall cost of operation through case studies of actual plant filtration applications.IntroductionThe use of woven filter cloth in liquid/solid separation applications is generally well known. Woven filter cloth, by the nature of the weaving process, offers unique consistency and repeatability when compared to some other filter media such as needled felts, papers, sintered structures and knitted cloth. This unique consistency and repeatability is particularly applicable to woven filter cloth produced using monofilament fibers. These fibers are consistent in shape and form the basis for a woven cloth with predictable pore size and throughput characteristics. Woven filter cloth can be used in most wet filtration applications. Typical examples are the separation of chemical and pharmaceutical solids from process liquors, waste stream solids capture, liquid foods clarification, mining separations, and polymer filtration.EnvironmentOne of the first considerations is the environmental demand of the given process. Though it is tempting to look immediately at the particles in a filtration process, it is often better to consider some of the more basic needs of the system. There are numerous materials available, both synthetic and wire cloth. Each has its own unique set of properties."

Jan 1, 2012

By Barry J. Welch

The production of primary aluminium can potentially lead to metal that, with minimum treatment, meets a high purity standard. Smelters that can achieve a significant proportion of their production in this manner have a competitive edge which is of growing importance as the use grows for such items as compact discs and the like. Superimposed on the desire to produce high quality metal are stringent environmental requirements that the industry must adhere to. The environmental &apos;legislation focuses on fluoride emissions and the approach adopted is towards a zero waste management philosophy. The fluoride recycling process does, however, result in volatile impurities being captured and recycled to the cell. Aluminium has an extremely high reduction potential and this results in a significant proportion of the recycled impurities being reduced at the electrolyte metal interface and thus contaminating the metal. This paper reviews sources of impurities and the impact of the operating procedures adopted on metal treatment.

Jan 1, 1996

By P. Klut, D. Groult, R. Marechalle, B. T. H. Bonnema

In the past 5 years, Compagnie Europeenne de Dezingage (CED) has developed a successful dezincing process and the St. Saulve pilot plant has evolved into a commercially successful production plant. Currently the plant meets all the required standards for scrap and zinc quality, output capacity, availability, and meets the prescribed environmental emissions standards. The initial process problems relating to zinc recovery, uncontrollable explosions and sodium hydroxide aerosol emissions have all been solved. Presntly, the yearly production of dezinced scrap is around 50.000 tonnes/year; this capacity is enough to supply the local market. This capacity can be increased easily to 65.000 tonnes/year or more. The market for dezinced material is growing due to the increased consumption of galvanized material on one hand and on the other hand the higher demand for high quality scrap. The proven technology of CED is currently patented worldwide, but CED is inviting licensees to implement the dezincing technology in other parts of the world.

Jan 1, 2000

The oxidation of zinc vapour plays a very important part in the operation of the Imperial Smelting Process. The kinetics of the reoxidation of zinc vapour by carbon dioxide and water vapour onto quartz and zinc oxide substrates is qualitatively understood and this pertains to the conditions found as the gases are being transferred from the furnace to the splash condenser. However, re-oxidation also occurs in the shaft of the furnace where the solid substrates are sinter and metallurgical coke. It was found that there was a threefold increase in the rate of oxidation on sinter, compared to quartz and a 30 to 300 increase in rate on the coke. This was attributed to the high surface area offered by these materials.

Jan 1, 2003