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By L. A. Barta

A new process for the leaching of chalcopyrite concentrates has been developed and tested in miniplant campaigns and locked cycle testwork carried out between 1996 and 1999. The process involves pressure leaching in a sulphuric acid solution, e.g. raffinate from copper solvent extraction. Iron in the feeds is precipitated predominantly as hematite in the autoclave, simultaneously with copper extraction. Gold and silver in the pressure leach residue are recoverable by conventional cyanidation, following flotation to remove elemental sulphur by-product. The results of recent miniplant tests and batch locked cycle tests are provided.

Jan 1, 1999

By Corby G. Anderson

Today, with a stringent economic and environmental climate prevailing in the copper business, there is increased interest in evaluating new processing alternatives for production. Hydrometallurgical pressure oxidation of copper concentrates is one of the more viable approaches and several technological candidates have emerged. Of these, an overlooked but industrially proven methodology utilizing nitrogen species catalyzation in the oxidizing pressure leach system may prove to be a feasible process alternative for the future. In this paper, the history of the system and its application to chalcopyrite concentrates will be outlined. In particular, a methodology for effective treatment of precious metals bearing chalcopyrite concentrates via partial oxidation at low temperatures and pressures will be discussed. Finally, the perceived economics of this unique industrially proven process will be delineated.

Jan 1, 1999

By Hector M. Henao

There is an increasing trend in the copper smelters to recycle electronic materials, which contain relatively high concentration of precious metals. As a consequence, the amount of precious metals lost in the slag phase is increasing. To determine the portion of the precious metals chemically dissolved and that associated with the mechanically trapped matte in the slag will be a key factor to improve the recovery of those metals. Thus, an experimental study was carried out to determine the distribution of precious metals (Au, Pt, Pd, Rh, Ru) between the equilibrated copper matte and iron-silicate slag phases. The experiments were made in a magnesia crucible at 1573 K and a fixed partial pressure of SO2 of 0.1 atm for the matte grades between 40 and 70 mass% of copper. It was found that the distribution ratios (defined as mass% X in slag/mass% X in matte, where X represents the precious metal) are around 10-2 for Ru, 10-3 for Au, Pt and Pd and 10-4 for Rh. The distribution ratios show a tendency to increase when the grade of matte is increased.

Jan 1, 2006

By Ken-ichi Miyazawa

A Center of Excellence (COE) titled the Creation of Nature-Guided Materials Processing, called Nature COE, has been established at Nagoya University. In the Nature COE, a new field of material research is being developed through learning the laws of nature, namely, methods of attaining ?appearance of the maximum function under the minimum substance and energy consumption?, which the nature and living organisms have acquired through their evolution in long period. As one of the specific features, an ?Open Cluster Program? was originated for promoting the researches conducted by young researchers and Ph.D. students with those in and out of the university and also for fostering them, together with such educational programs for Ph.D. students as the research incentive, the oversea training and the international lodging seminar programs. The Open Cluster Program has been found to be effective for fostering of young researchers and students, for promoting their researches, for gathering researchers and knowledge from the world and for propagating the research fruits. Through conducting these programs, world-highest intelligent fruits and a gathering of young minds to lead the new field are expected. In this COE, the researches are conducted on (1) materials used for living bodies, (2) mimicking structures which nature or living bodies are forming and (3) materials processing by mimicking processes to form the structures observed in the nature or the living bodies. These researches are conducted by four groups to extend the processes observed in the natural world to a new type of processing that is thoroughly rationalized by plunging a scalpel of engineering, and to establish a new academic field of materials science and engineering.

Jan 1, 2006

By Cristiän Vargas, Jaime Simpson, Gerardo Cifuentes

"This paper presents a new process for the precipitation of Sb and Bi present in copper refinery electrolytes in the presence of Pb02 (Chilean Patent No. 45,037). To establish the conditions under which the precipitating compounds form, it was necessary to evaluate the amount of PbCh consumed, antimony extraction efficiency, precipitate stability, reaction kinetics, diffraction analysis and X-ray fluorescence, separation of size, plus observation of the precipitates in the electron microscope. Preliminary tests were carried with synthetic copper refinery electrolyte, and then the final testing was done with electrolytes from Chilean refineries. This process provides a real alternative for the treatment of copper refinery electrolytes for the control of Sb and Bi in solution; it is very simple to operate and is low cost compared with competing processes.Introduction.A high quality copper cathode implies a cathode free of impurities. The electrorefining process seeks to eliminate these impurities from the copper anode (99.5% purity) by its dissolution in an acid electrolyte using chemical and electrochemical reactions. As a result of this process, a cathode (99.99% purity) is obtained. If the concentration of impurities in the electrolyte, from the dissolved anodes, begins to increase; particularly if the antimony concentration in the electrolyte increases up 500 ppm, the formation of floating slimes which are a major cause of contamination of the cathode is favoured. The most important impurities from the point of view of their effect on the quality of the cathode copper, are Ag, As, Sb, Bi, Pb, Se and Te. Silver is necessary for the control of Se and Te. To control all of these impurities, it is necessary to establish different methods or parameters of control in copper electrorefining. These parameters are anode composition, additives, purification of the electrolyte, current density, acidity, etc."

Jan 1, 2012

By Don Ibana

The use of solvent extraction (SX) in process metallurgy is particularly attractive as it is applicable to a wide range of solute concentration and pH, and it allows complete separation of chemically similar metals such as nickel and cobalt and the rare earths among others. It is therefore applicable to the processing of low grade and complex ores, which is increasing and expanding owing to the diminishing reserves of quality ores, and this has driven the increasing and expanding use of SX.The current SX technology, however, has inherent limitations owing to the use of mechanical agitation as it induces high shear mixing. Excessive shear produces very fine droplets, and while this favours mass transfer, it also leads to sluggish phase separation. High shear mixing is also known to favour crud formation. All these factors as well as high power and reagents consumptions contribute to poor process efficiency. Electrostatic solvent extraction (ESX) is similar to conventional SX except that mechanical agitation is replaced with electrostatic agitation. In direct contrast to mechanical agitation, it allows the production of very small droplets that can be made to maintain intense motion, which favours mass transfer, without affecting the phase separation. In addition, as it uses an electrostatic field, the power consumption is minimal. Hence, it promises to be a superior alternative to conventional SX mixing although an application of the technique is yet to be achieved.Our work to develop an application of the technique in process metallurgy has now established that electrostatic field has no effect on either the stability of the reagents or the chemistry of the process. A volumetric flowrate that is comparable to that of a conventional sieve plate pulse column is achievable. We have also established that electrostatic fields can be made to yield much narrower droplet size distributions than those of mechanically agitated contactors, and they allow better control of droplet motions, which include oscillation and linear motion and hence, mass transfer. These are significant advancements toward our goal and shall be discussed in this presentation.

By Marcelo Jimenez Bustos

The Chagres Smelter was the first in Chile to follow environmental regulations to control sulfur dioxide emissions. Because of this, the operation and development plans have had to incorporate environmental planning as part of its policies for almost three decades. The present article shows the development of the environmental standards applied to its operations, investments and operational improvements carried out to meet the regulations and improve competitiveness. Results to-date and future plans are outlined, as well as their impact on operations and the environment.

Jan 1, 1993

By M. Jennings

In 1987, Echo Bay discovered a major silver/gold ore body at their McCoy property in Nevada, and quickly made a decision to build a 5000 tpd mill which was expanded during the design to 7500 tpd. Since the ore reserves consisted of cyanide leachable oxide as well as sulfide, the plant flow sheet involved an oxide leach, a gravity circuit, and lead sulfide and a pyrite sulfide recovery by flotation. The paper describes the process development, equipment selection, plant design and the startup of the oxide treatment.

Jan 1, 1990

By Dan Mancuso

This case study is an example of how Encyle/Texas, Inc. (a subsidiary of ASARCO) responded to various socio-economic forces by converting an idle zinc hydrometallurgical refinery into a metals recycling facility. The facility accepts metal-laden process waste streams and produces various "synthetic ores" which are sold back to industry. Acceptance and reactions by industrial, political, economical and regulatory interests towards the project are also discussed.

Jan 1, 1992

By Alain Jardy, Thibaut Quatravaux, Denis Ablitzer

"A numerical model of the Vacuum Arc Remelting process has been developed and applied to simulate remelting of various metallic materials, such as specialty steels, titanium and zirconium alloys. In practice, electromagnetic stirring is sometimes used, resulting in a complex 3D molten metal flow. After having validated the numerical model for different remelting conditions, we can use it to study the effect of applying a constant or alternated magnetic field on the thermohydrodynamic behaviour of the melt pool. The intensity of flow turbulence, computed with a classical k-E model, is shown to depend strongly on the nature of electromagnetic stirring.IntroductionThe principle of the Vacuum Arc Remelting (VAR) process, illustrated in figure I, consists in melting a consumable metallic electrode of the required grade under a high vacuum, in order to obtain a sound ingot of good structural quality.During remelting, an electric arc is maintained between the tip of the electrode and the top of the secondary ingot, in order to ensure melting of the electrode. The metal droplets fall through the arc plasma and progressively buid up the ingot, which solidifies in contact with the walls of a water-cooled copper crucible. The secondary ingot formed in this way contains three distinct zones, corresponding to the liquid pool, fully solidified metal and intermediate mushy zone. In order to stabilize the arc, it can be confined with the aid of a magnetic field created by an external induction coil. This field can also be used to stir the liquid metal, the rotation induced being in the orthoradial direction. By reversing periodically the coil current, stirring can be alternated."

Jan 1, 2004

By Wenshan Zhang

This paper described the present status of China electrolytic manganese industrial production. Electrochemical reactions on cathode and anode, the major technological process, technical requirements on the production and technical index and quality control of the products and the ways of increasing current efficiency during Manganese electrolytic process have been expatiated.

Jan 1, 2006

By G. Roy Chaudhury

Adsorption techniques are comparatively low cost and effective for treatment of arsenic contaminated drinking water. Various adsorbents such as alumina, ferrihydrite and manganese ores have been used, but there has been little investigation of modifying the structure of ferrihydrite to improve its adsorptive efficiency of As(III) and As(V). In the present study the incorporation of manganese oxide into the ferrihydrite structure was carried out and the prepared materials used in arsenic adsorption experiments. The compounds were X-ray amorphous, but TGA/DTA and FTIR analysis showed some structural characteristics. Sorption studies reported in this paper indicate the excellent arsenic removal properties of the manganese/iron compounds with a loading capacity of 0.3 mmol/g. Adsorption follows first order kinetics and the results fitted to adsorption and mass transfer models. Arsenic levels in water containing 1 mg/L As(V) were reduced by 50% in 20 minutes and 90% in 60 minutes using 1 g/L manganic ferric oxyhydroxide.

Jan 1, 2003

By Graeme Miller

The geotechnical characteristics of the ore are important in understanding the kinetics of a copper heap leach. These characteristics can indicate potential problems and can be used to determine the semi-quantitative changes in field kinetics as compared with column kinetics. The application of this approach allows a more rigorously based determination of ?scale up factors? than has been the case the date. The shrinking core model has been shown to be a poor predictor of leach kinetics based on the crushed ore size distribution. However the model itself is a very useful tool to analyse commercial heap data. Significant geotechnical parameters such as: bulk density / stress characteristic, limit moisture capacity and particle density are used to determine the effect of changes on the diffusion controlled leach rate. By consideration of the geotechnical reaction of the ore mass the leach rate changes are related to changes in these variables. Analysis of commercial heap data has indicated effective diffusion lengths of up to ten times the largest particle size.

Jan 1, 2003

By J. L. Delplancke

During copper electrowinning in sulphate electrolyte, intense oxygen evolution takes place at the anode. Lead alloy anodes are progressively replaced by dimensionally stable anodes in order to avoid the cathode contamination by dissolved lead. The electroactive coating of these anodes has to be as cheap as possible, adherent to the substrate, electrochemically stable and has to be efficient at high current density and high temperature. This requirement is even demanding in case of copper electrodeposition for the production of thin copper foils for the electronic industry. The production of thin (20 µm thick) copper foils for the printed circuit boards requires high purity copper electrodeposited at a current density as high as 7,000 A/m2. The choice of a long term coating composition is driven by economics. The purpose of this paper is mainly to review the anode compositions suitable for copper electrowinning and for copper electrodeposition at high current density. A short description of preliminary results obtained with a new anode coating on a titanium substrate is also presented.

Jan 1, 1999

By Roald Ysteboe, Finn Olesen

"Elkem has developed a process that utilizes SPL as a raw material for pig iron production. This process will be demonstrated in industrial scale during 2008 and 2009. The process developed produce iron, and the reduction material used, is the carbon present in the SPL. The iron source could be either virgin iron ore or waste/recycled material from the steel industry. The SPLrefractory and bath material is dissolved in the slag produced. The slag is designed so that any leaching of environmentally dangerous elements is minimized. This process can in addition to SPL, consume other types of waste derived from the primary production of aluminium. Elkem intends to supply this demo project with SPL and other waste products from external sources, domestic as well as international ones.IntroductionSpent Pot Lining (SPL) is generated when an electrolytic cell for producing aluminium is taken out of service and the refractory and carbon lining is removed from the steel potshell.The yearly generation of SPL world wide is exceeding 500 000 tonnes. The major amount of this quantity is stockpiled or land filled, unprocessed.SPL contain large amount of water soluble fluorides and some amount of cyanides and is classified as hazardous waste in most countries."

Jan 1, 2008

By Roberto Parra

The wear and corrosion phenomena in the furnace lining of the ferrous and non ferrous pyrometallurgical processes are complex problems where chemical, interfacial and mechanical phenomena are presents. The characteristics of the processes determine the conditions to which these materials are submitted, where the thermal conditions reached during the operation is one of the most important parameter. Assuming that all the degradation phenomena are thermal activated, the rate of the different steps of the wear mechanism will depend on the thermal field in the lining. In view to apply the independent physicochemical knowledge of degradation mechanisms to the analysis and design of furnace lining the methodology of the Nodal Wear Model (NWM) was done. It combines the mathematical modelling of the heat transfer in the lining with the physicochemical control equation for the wear-corrosion phenomena. The NWM has been applied to different examples: theoretical analysis, laboratory scale test and industrial applications. We present in this paper the theoretical background of the model and two examples of applications: the sole of an electric furnace and the earth of a blast furnace.

Jan 1, 2006

By Ruben Alvarado

The need to increase business competitiveness while complying with environmental requirements represent the great challenge that the Caletones smelter has decided to face in a new development project with a compromising and willing alliance with its workers. To date, the project is at the feasibility stage, with start up scheduled for the middle of the year 2002. The processing capacity of the Teniente Converters will be increased to levels up to 2400 tpd of chalcopyrite-based concentrates containing 30% Cu, by means of more intensive use of oxygen and improved stabilization of the overall operation. Productivity increses in the converting of white metal and the pyrometallurgical treatment of slag are also planned. As a result of related strategies, the productivity of the supporting facilities, included the capacitiy of the sulfuric acid plants, will be increased. An intensive and well-designed labor-upgrading scheme will allow the transformation of every worker into an expert in his working areas, thus becoming an active driving force in technology development. Mechanization, appropiate infrastructure, and complete process control and instrumentation will give to the skilled and motivated personnel the necessary tools in order to attain the highest potential ever reached with the Teniente technology. The necessary investment for this project based on the adding facilities to the existing plant is only a third of that required to reach the same objective for a greenfield plant, thus yielding a very high return on investment.

Jan 1, 1999

By Ibrahim Yusufoglu, Cem Kahruman, Sedat Ilhan, Ahmet Orkun Kalpakhi

"Scheelite is the main raw material in tungsten production. In hydrometallurgical processes, extraction of tungstate ions into solution is very important. During the leaching of scheelite in oxalic acid solutions, tungsten dissolves as a chelate complex. Scheelite includes impurities along with calcium tungstate. Determination of the dissolution of these impurities is important in the subsequent tungsten production stages. In this study, scheelite was dissolved in oxalic acid solutions and the dissolution of impurities was investigated. The quantities of dissolved impurities were determined by ICP - OES and characterization of the undissolved impurities in the leach residues was carried out by SEM - EDS analysisIntroductionScheelite and wolframite ores are used for the industrial production of tungsten. Both ores are dissolved in acidic or basic solutions, and ammonium paratungstate is obtained as an intermediate product. Prior to crystallisation of ammonium paratungstate, all the impurities must be removed. Among these, Fe, Si, P, Mn, Mg and Mo are classified as ""harmful"" elements and different methods are used for their removal [1]. During purification, solvent extraction, ion exchange, etc. methods are used.Potashnikov et al. [2] studied the dissolution of scheelite in acidic solutions and the effects of stirring speed, temperature and oxalic acid concentration on the dissolution kinetics.There are no works in the literature about the removal of impurities from scheelite ores in oxalic acid solutions. Therefore, the aim of this work was to investigate the dissolution mechanisms of impurities during the leaching of scheelite in oxalic acid solutions. The effects of temperature and oxalic acid concentration on the dissolution were also investigated. In addition, the characterization of the impurities which were not dissolved was studied."

Jan 1, 2012

By Luis Velazquez, Andrea Zavala, Nora Munguia

"This paper is aimed at describing the evolutive strategy in which the University of Sonora is following for optimizing the organic and inorganic material life cycle in the products used on campus. The institutional strategy has be oriented towards new patterns of behaviors in order to integrate the principles of sustainability as a guideline for preventing, eliminating, and/or reducing the negative environmental and occupational impacts generated when performing university substantive functions of teaching, research, and outreaching and partnership as well as its management operation tasks.IntroductionThe University of Sonora is the largest and most important university among several other universities in both the city and the state. It is a public university with a 29,792 students in three campuses in the state. The main campus of the University of Sonora is located in the capital city of Hermosillo, which has a population of more than 609,829, in the state of Sonora in the northwestern region of Mexico [1].Despite the fact that in the University of Sonora there were, in the eighties, some projects dealing with environmental issues, there was not until 1992 that the sustainability efforts were really initiated. It happened when the Sustainable Development Group was created in the Department of Industrial and Systems Engineering as a response to the need for adapting the industrial engineering curricula to the challenge of sustainable development [2]. In order to promote sustainability, it has been necessary to cope and break with several university paradigms. For this reason, the strategy for becoming a sustainable university has continuously evolved throughout the years from a simple structure composed by individual and isolated projects to a systematic and integrative Sustainability Management System. Thanks to this evolution, the University of Sonora has won a respectable reputation in the greater community and it is seen in the region as an icon of sustainability promoter. In this sense, the substantives functions of education, research, and outreach and partnership, which are considered supportive and integrative, have also evolved to play a key role for the success of sustainability initiatives.The institution has followed four avenues for becoming a sustainable university; education, research, outreaching and partnership and greening the campus [3]."

Jan 1, 2008

By Theo Lehner

"During my first contact with industrial metallurgy as a summer vacation worker at the Steelplant at Luleå, Sweden, I came during a visit to MEFOS into contact with works of Prof. Worner caried out during the piloting of the Worcra continuous steelmaking process. These tests are still today remarkable as an innovative step in the art of metalmaking. By that they involved the necessary ingredients for the development of our art: seeing, knowing and doing. Industrial injection as applied during slag fuming will be discussed below.Phenomena of injection metallurgyPhenomenon according to Collins dictionary is"" anything that can be perceived as an occurrence or facts by the senses"". To open the senses for the interesting phenomena in pyrometallurgy must be the main task of any educator. The investigations by Engh et al. around the mixing phenomena of the WORCRA process are an early example of combining senses with knowledge. To see what you model must be a crucial part in any development. This can also involve to see and control that one is subject to the same conditions as in published models. Below the need ""to see"" will be illustrated by some recent investigations around slag fuming. In the literature various models for reactions occuring during the fuming of slags are presented. Two recent models hint ·ata) the occurrence and importance of iron for the fuming processb) the occurrence and importance of lead droplets during respectively."

Jan 1, 1996