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By Frank M. Kimmerle

Spent Potlining (SPL) contains recoverable chemical elements (C, F, Na and Al) which are lost in stabilization or immobilization processes primarily aimed at eliminating cyanides and reducing leach rates of soluble fluorides prior to landfiling. They can be recovered in a variety of mineral forms for recycling in the aluminum industry and elsewhere. Alcan has developed a cost-effective hydrometallurgical route, combining a number of proven unit processes to destroy cyanides, recycle the chemical values and provide a zero-discharge process. Pilot plant studies of this Low Caustic Leach and Liming (LCL&L) Process prove that the fluoride scan be converted to acid grade fluorspar, while the sodium and aluminum are recovered as a sodium aluminate and caustic feed to the Bayer Plant operations. The remaining brick and carbon fraction constitutes a high ash solid fuel which meets TCLP leach criteria and whose reduced sodium content enhances its value as a chemical reducing agent.

Jan 1, 1994

By Jim A. King

The total pressure oxidation of copper concentrates is a potentially viable option for treating copper concentrates that are either low grade or contain significant impurities. Both concentrate types are heavily penalized in smelter contracts. The total pressure oxidation process involves autoclaving the copper concentrate at temperatures of 200-220 C under oxygen pressure. The autoclave discharge can be separated into a solid (oxidation residue) and a liquid (oxidation solution) product. The oxidation solution can be treated for copper recovery by solvent extraction - electrowinning or by direct electrowinning. The direct electrowinning recovery of copper requires prior removal of selenium and tellurium by cementation on finely divided scrap copper. The oxidation residue is washed thoroughly to remove acid and dissolved copper prior to precious metals recovery by conventional cyanidation in the presence of lime. The results of a benchscale investigation involving a number of copper concentrates are reported. Copper recoveries in autoclave oxidation and gold recoveries by cyanidation of the oxidation residue exceeded 99%. The results of benchscale experiments to demonstrate copper recovery are described. Various flowsheet options are presented.

Jan 1, 1993

By Florian Kongoli

New operating conditions and process parameters are often necessary in today's industrial practice of non-ferrous smelting and converting in order to accommodate various new chemical compositions of mineral charges and environmental requirements or to conceive new and more efficient industrial technologies. An important parameter in non-ferrous smelting and converting is the liquidus surface of multicomponent slags. This surface is affected by multiple factors such as temperature, gaseous potentials, the content of each component in the slag, etc., and cannot be quantified by the existing ternary liquidus diagrams. In this work a new type of representation of the liquidus surface of multi component systems has been presented by means of a thermodynamic model. This representation waives the need of the multidimensional representation of multi component systems and yields practical two-dimensional diagrams, which can be easily used in the industrial practice.

Jan 1, 2000

By Fathi Habashi

"Davy, Faraday, and Bunsen laid the foundation of electrometallurgy which had a· great impact on other areas of metallurgy. Electrometallurgy is presently dominated by the production of aluminum, the electrorefining of copper, and the electrowinning of zinc. It has also been successful in the electrowinning of copper from solutions obtained by leaching-solvent extraction. Electrowinning processes, however, are capital intensive. Improvement of the present technology should be intensely investigated especially when it is expected that such processes will increase greatly as a result of a shift from certain pyrometallurgical processes to pressure hydro metallurgy.INTRODUCTIONPyrometallurgy was used for thousands of years to produce copper and iron from their oxide ores!). Today it is still the only route to produce iron and steel and it is certain that it will remain so for many decades to come because pyrometallurgy is most suitable for the treatment of high grade oxide ores. Even when high grade iron ores are exhausted, it is possible to beneficiate the low-grade ores and produce pellets suitable for reduction in the blast furnace, which is a very efficient reactor, being a heat exchanger as well. Hydrometallurgy on the other hand can be traced to the time of alchemists in the Middle Ages when they were seeking to transmute base metals into gold, and thus were able to prepare many acids and bases which are the essential leaching agents."

Jan 1, 1997

By I. Iwasaki

Platinum group elements (PGE) are often found in arsenide and sulfarsenide minerals as inclusions in copper-nickel bearing gabbroic rocks. Major losses of platinum in flotation have been attributed to the poor recoveries of the arsenic minerals. Flotation characteristics of a synthetic nickel arsenide and arsenopyrite were studied through rest potential and oxidation rate determinations, surface analyses, and micro-and batch-flotation tests. The use of nitrogen during grinding and flotation together with copper activation improved the PGE recoveries from Duluth Complex ores. The flotation behaviors of the sulfarsenide minerals are still unresolved. The role that electrochemical interactions play among arsenides, sulfarsenides, sulfides and grinding media on their f10atabilities is discussed.

Jan 1, 1988

By Andreas H. Vassiliou

Organic materials are major constituents of the ore in several uranium deposits. Some of these deposits have been described as "urano-organic" because, the organic materials are believed to have provided the dominant control for the accumulation and deposition of uranium and are directly and intimately intermingled with the uranium. The nature of these urano-organic deposits has been problematic in terms of (a) the origin of the associated organic materials and (b) the specific form of' occurrence of uranium. The organic materials in urano-organic deposits have been genetically related to both coal and petroleum or their progenitors or deriva-tives. Analytical data presented here (infrared, chemical. D.T.A.) suggest that coaliferous materials or related plant derivatives represent the main source of the organic fractions in practically all major urano-organic ores analyzed from the Colorado Plateau and other areas. Recognition of the specific form of occurrence of uranium in urano-organic deposits has been problematic mainly because the uranium is usually in an extremely fine-grained and disseminated state in the organic matrix. Electron microprobe and X-ray diffraction analyses presented here show that fine-grained uranium minerals, specifically uraninite or coffinite. are disseminated in the organic matrix as the predominant form of uranium in most major deposits; however. the presence of true organo-uranium compounds is also suggested for some deposits.

Jan 1, 1981

By Satoshi Itoh

Phase equilibria and activities of the components in the liquid lead-antimony-oxygen temary system, which is of fundamental importance for discussing the recovery of lead and antimony from a used lead-battery, have been investigated at 1173 and 1223 K. The two liquid phases of metal and oxide were observed at the temperatures studied, and the tie lines indicating isoactivities were determined. The activities of PbO, Sb015 and Sb203 in the PbO-SbOu and PbO-Sb203 pseudo-binary systems were then obtained by applying the Gibbs-Duhem equation to the phase relation of metal-oxide equilibrium. Both in the pseudo-binary systems the activities exhibit negative deviations from Raoult's law. The vapor pressures of lead, antimony and lead oxide, antimony oxide were calculated by using the activities of the components in the lead-antimony-oxygen ternary system. As a result, an oxidation of antimony concentrated in an anode slime followed by evaporation as antimony oxide Sb406 was found to be considerably effective for the recovery of lead and antimony from a used lead-battery.

Jan 1, 2003

By Raymond F. Dalton

Despite the ready availability of numerous zinc sources, the process of solvent extraction- electrowinning (SX-EW) has as yet found little favour in the zinc industry. It is suggested that this is largely due to the previous lack of availability of suitable selective reagents having the particular features required to enable them to fit in to a solvent extraction-electrowinning based process for zinc, particularly with regard to strength and selectivity for zinc over iron. This paper describes work on the development of new selective extractants for the recovery of zinc from both sulfate and chloride aqueous solutions and suggests how they might be integrated into new zinc processes.

Jan 1, 1994

By Mansoor Barati, Shaghayegh Esfahani

"The slag from extraction of ferrous and non-ferrous metals is a potential heat source which if treated properly can contribute to recovery of a significant amount of energy. The waste heat of slag may be used to generate steam, synthetic fuel gas, or electricity. Although several technologies have been investigated for this purpose, very little has been achieved in terms implementing the technology in industry. In this article, the development and application of various granulation techniques are reviewed and the methods to recover energy from granulated slag are discussed.IntroductionEvery year, more than 422 million tons of slag is being produced around the world as a by-product of the metal manufacturing at temperatures of up to 1300-1600°C [1, 2]. Currently slags are either disposed of or treated by processes such as granulation. Through the granulation process, most slags can be converted into a material which may be fully used as a cement feedstock. Conventional cement production is an energy intensive process with large emissions of CO2; therefore, the replacement can both be energy saving and environmentally friendly. However, for this purpose, the slag should have what is known as a “glassy” content (i.e. it should be amorphous) which requires rapid cooling rates that are not easily achieved due to the very low thermal conductivity. The main challenge in all these processes is to granulate the slag at a high cooling rate while the heat is also being recovered."

Jan 1, 2012

By W. G. Davenport

The offgas from flash furnaces inadvertently contains dust. The dust contains 25 to 30% Cu so it must be treated for Cu recovery. This is almost always done by recycling it back through the flash furnace*. This chapter shows how dust production/recycle is included in our matrix calculations. It then discusses the effects of dust production/recycle on flash furnace industrial oxygen and oil requirements. It concludes that re-smelting of dust requires considerable industrial oxygen and fuel, so that dust production should be minimized. Recycled dust also takes the place of new concentrate in the flash furnace feed system, decreasing Smelter productivity -another reason to minimize dust production. Compositions of industrial dusts are given in Appendix VII and Table 18.3. Industrial quantities are given in Tables 2.1, 3.1, 19.1,20.1' and Appendix VI.

Jan 1, 2001

By Gordon A. Irons

"Powder injection for melt refining is widely practiced in the steel industry, and is gaining acceptance in the non-ferrous industries. In these commercially-important systems, the thermodynamics and kinetics may be very complicated. More than one element may be removed by refining, and often the refining agents are not just one compound. In this paper, the thermodynamic and kinetic aspects of these processes are reviewed. A number of examples are given, such as the desulphurization of iron with a variety of reagent mixtures, and selenium removal from copper with several different reagent combinations.IntroductionI am very pleased and honored to present a paper at this Symposium recognizing the many contributions of Professor Howard Womer. Even at the time I was an undergraduate student, the WORCRA process was part of the curriculum. I remember at the time that I was fascinated by the concept, and due to it and the many other rapid developments in Process Metallurgy, I chose it as my field of study. I think the Symposium is testimony that Professor Womer has touched the lives of many others as well.My original assignment was an overview of the basic aspects of gas and solids injection. However, I reviewed most of this material at the Savard/Lee Symposium [1]. In the present paper, I will present some of the basic issues related to refining with powder injection, using work that we have recently completed in both ferrous and non-ferrous systems."

Jan 1, 1996

"Mixing phenomena in a bottom blown air-stirred one-seventh water model of CLU (Creusot-Loire Uddeholm) reactor was studie9-using three different configurations of straight circular nozzles fitted axially at the bottom of the vessel. The mixing time has been determined by pH measurements at various gas flow rates, bath heights and nozzle orientations in the presence and in the absence of a second phase.Experimental results reveal that the mixing time decreases with increasing gas flow rate. For a given gas flow rate the mixing time increases non-linearly with increasing bath height. Off-center configuration gives slightly lower mixing times as compared to center configuration. It is found that the contribution of buoyancy to the total stirring energy density is very small, but its contribution increases with increasing bath height. In the presence of an upper oil layer, the mixing time increases significantly for all configurations.IntroductionIn high temperature metallurgical melts mixing is carried out by injection of a gas either from top or bottom of the vessel in order to accelerate the rates of chemical reactions and to promote bath homogenization. When a gas is injected into a liquid through a submerged lance, porous plug or nozzle, the gas, rising as a two phase plume to the surface, imparts momentum to the surrounding liquid and causes gross circulation in the bath which promotes mixing."

Jan 1, 1997

By Emmanuel N. Zevgolis

After the Krupp-Renn process was shown to be unsuitable for treatment of the Greek nickeliferous laterites, the LM process was developed. It involved roasting reduction up to metallic iron in a Rotary Kiln (R/K) and smelting in an Electric Furnace (E/F). Ferronickel (with 15% Ni) produced in the E/F, was upgraded to 90-95% Ni in an 02 converter. Raw Ni was then electrolyzed to pure Ni. The LM process was not applied for very long however, due to various problems. So, the Larco process was developed, i.e., pre-reduction in R/Ks, smelting of the calcine in E/Fs for ferronickel production (15% Ni) and enrichment to 20% Ni, in an O2 converter. Until now, many technological improvements have been invented and applied or adjusted to the process, which have made it a fully reliable and competitive one. sohe of the improvements were the invention and application of a new granulation process for liquid ferronickel, the modification of the existing R/Ks, E/Fs and converters and the design of new ones, and others that are described in the paper. Keywords: Ferronickel, metallurgy, laterites, LM process, Larco process

Jan 1, 2004

By C. Hennesmann, D. Maijer, S. L. Cockcroft, P. Yo

"Die cast aluminum wheels are one of the most difficult automotive castings to produce because of stringent cast surface and internal quality requirements. As part of a collaborative research agreement between researchers at the University of British Columbia and Canadian Auto Parts Toyota Incorporated, work has been underway to predict heat transport and porosity formation in die cast A356 wheels. The basic heat transfer equations have been solved using the commercial finite element package ABAQUS to which specialized routines have been added to predict porosity. Preliminary work on predicting porosity formation focused on using the Niyama parameter as a measure of the probability of porosity. The latest version of the model incorporates a new fundamentally based porosity criterion, which takes into account the effect of hydrogen concentration. The development of this model together with its application to a series of cylindrical test castings as well as a production cast wheel are presented.I. IntroductionDie cast aluminum wheels are one of the most difficult automotive castings to produce because of stringent cast surface and internal quality requirements. Microporosity, in particular, is a common defect that can adversely affect wheel quality. The mechanism of microporosity formation in aluminum alloys is complex owing to its dependence on the interaction of a number of phenomena occurring during solidification including the decrease in hydrogen solubility, the decrease in volume, the development of the solidification structure, and the increase in difficulty in interdendritic feeding [1]. As a result, the amount, size, and distribution of microporosity is affected by a large number of casting parameters including thermal variables, melt composition, grain structure, modification, and inclusion content, making optimization by trial-and-error methodologies difficult.The use of criteria functions, based on thermal conditions during casting, offers a relatively simple approach to predicting microporosity. In practical terms, they are useful because they provide a straightforward method of assessing the impact of varying casting parameters on porosity through various thermal parametersl21 such as thermal gradient, cooling rate, solidification time, and solidus velocity. Drawbacks of criteria functions include insensitivity to varying hydrogen concentration and the limitation to qualitative predictions. Consequently, in aluminum alloys, attempts have been made to develop models incorporating the effects of hydrogen gas and microstructure evolution. However, these types of models represent a significant increase in complexity and sacrifice the simplicity and ease of application of the thermally based criteria functions."

Jan 1, 2001

By I. Gaballah

The chalcopyrite ore's anodic and cathodic electrodissolution are studied using a Porous Pulsed Percolated Electrode (3PE) reactor. Stationary solid electrode experiments are also performed to explore the mechanism of electrochemical dissolution of chalcopyrite. Experiments with a low - grade natural ore have been carried out at 25 "C in solutions containing 1 M NaCl and 1 M HCl. Galvanostatic and potentiostatic conditions are employed. The influences of current and potential on selectivity of the chalcopyrite ore dissolution are assessed. Anodic oxidation of this ore leads to a preferential dissolution of iron bearing minerals, whereas cathodic reduction is more selective with respect to chalcopyrite. However, in both cases the electrochemical dissolution is incomplete and the current efficiency is low. Design of the actual reactor has to be modified to increase the bed conductivity and to allow continuous experimentations.

Jan 1, 1994

By J. Fraser Forbes

"The meaning of the term ""process control"" has evolved significantly since its widespread use began in the manufacturing industries in the 1940s. Further, the scope of process control applications has drastically increased both in terms of the breadth of industries using process automation technologies and the vertical integration of these technologies within a single industry. This evolution and integration of process control technologies within the manufacturing industries has proceeded to such an extent that process automation is an integral part of modern business practices.This paper will examine the current status of process control technology from simple process regulation through process performance optimization to business planning. Each layer of the operations automation hierarchy will be discussed both in. terms of the current state-of-the-art and the directions in which these technologies are evolving. The key tools and tasks necessary for success at every level of the automation hierarchy will be introduced. Finally, the critical challenges that must be faced in accomplishing the goal of complete Computer Integrated Manufacturing (CIM) will be described.Finally, although this paper addresses issues of practical importance to any manufacturing company, the discussions will be framed in terms of the particular challenges facing and the opportunities available within the materials manufacturing industries."

Jan 1, 2000

By Zizheng Zhou

The separation of cobalt from other base metals can be achieved using diffusion dialysis in a two-compartment reactor separated by an anion exchange membrane. In this work, a Neosepta AFX membrane was used to study the separation of various metals in an acid-chloride solution. The separation of one metal from another was investigated on the basis of the various chloro-complex stabilities. The metals investigated included cobalt, nickel, copper(II), iron(III), aluminum, zinc and cadmium. The impact of several critical experimental conditions, including the initial metal and chloride concentration in the feed solution and their initial concentration in the receiving solution, on the separation factor and the metal transfer rate is reported in this work. Effective separation of different metal pairs was achieved under the experimental conditions.

By A. J. Paul, K. O. Yu

"Today, foundries are moving towards the use of models and design tools to gain a competitive advantage in producing castings of high desired quality. This leads to a growing alliance between foundries, software developers and researchers seeking to model, visualize and understand the phenomena taking place during the casting process. In addition, there is a need to develop affordable techniques to produce parts in small lot sizes. This leads to the development of a Flexible Manufacturing System consisting of: (1) up-front computer-aided engineering; (2) computer integrated proto typing with solid freeform fabrication; and (3) fabrication of the actual mold and related equipment to cast the part.This paper discusses some of the developments that are taking place today in the areas of modeling the physical phenomena during the casting process as well as towards developing a Flexible Manufacturing System for producing cast parts. Areas that require most work involve prediction of defects and mechanical properties using simplified analyses. In addition, electronic data sharing for collaborative engineering between geographically dispersed team members is also discussed. Case studies are presented showing successes as well as failures.IntroductionCasting, one of the oldest forms of metalworking, has recently seen a flurry of developments in the area of solidification modeling. These developments have come about after the realization that, in order to stay competitive, foundries need to reduce their scrap rate and production costs, and increase casting quality. Even though this is not new knowledge for foundry engineers, the tools to help them achieve this goal are just being developed and put in place for use by foundries. Several state-of-the-art software packages are currently available to analyze the solidification behavior in complex shaped castings. These packages make use of several different approaches for solving the various problems associated with casting processes. The overall architecture of a comprehensive solidification modeling system is shown in Figure 1."

Jan 1, 1994

By Dean Ilievski

Mathematical modelling of the precipitation process requires that the kinetics of crystal growth, nucleation and agglomeration be known: This paper reviews the current state of knowledge on these precipitation sub-processes (ie. growth, nucleation and agglomeration) and describes a number of experimental techniques for estimating their kinetics. The experimental methods used to generate the precipitation data and the data analysis techniques used to extract the kinetics information from the data are discussed separately. There is no universal "best" technique for determining the kinetics. However, studies on multi-crystal systems are more reliable for modelling purposes than are single crystal studies. The selection of a technique will depend on which sub-processes are present. A problem with all kinetics studies is that there is generally a large uncertainty in the estimated kinetic parameters. This stems from the scatter in the experimental data being further propagated by the mathematical techniques used to extract the kinetic parameters.

Jan 1, 1996

By Hiroyuki Matsuura, Fumitaka Tsukihashi

"Emission of CO2 gas from steelmaking industry covers more than 12 % of total CO2 emission in Japan. Though many efforts have been made to curtail energy consumption and high energy efficiency of Japanese steel production process has been achieved so far, further reduction of CO2 emission is strongly requested to develop sustainable steel production process and produce “green material”. Recently, authors have proposed the innovative hydrogen production process, in which water vapor is reacted with discharged steelmaking slag to produce hydrogen gas. This reaction can be achieved without any external energy source and operated by huge thermal energy associated with steelmaking slag and FeO or unrecovered Fe droplets that are relatively rich in the slag. In this paper, thermodynamic calculation results with various initial conditions in terms of hydrogen productivity were presented. Laboratory-scale experiments were also conducted to clarify the validity of thermodynamic calculation and the reaction rate in realistic conditions.IntroductionIronmaking and steelmaking process from iron ore through blast furnace and BOF is an essential steel production route for Japanese steel industries to supply high quality steel products in large quantity to society stably. Blast furnace – BOF process requires huge amount of fossil fuels such as mainly coal, resulting the emission of considerable amount of CO2 gas. Since the emission of CO2 gas from steel industries, about 147 Mt (FY2011), accounts for approximately 12 % of domestic CO2 gas emission in Japan (FY2011),[1] it is an urgent issue for steel industries to develop environmental-friendly ironmaking and steelmaking process and reduce CO2 emission. Various kinds of gases and by-products generated from ironmaking and steelmaking processes have been recycled as much as possible at present. Enormous thermal energy is also generated from processes and released to surrounding atmosphere as various forms such as sensible heats of gases, molten steels or by-products, and as heat losses. However, these energies are not utilized before final dissipation to atmosphere. Although various technologies to utilize thermal energy from ironmaking and steelmaking processes have been attempted to develop, practical application of these technologies has not been achieved because the thermal energy is not always useful as an energy source. In steelmaking process by BOF, fluxing agent such as CaO is added during reefing and thus about 100 kg/t-steel of steelmaking slag are generated. Since the steelmaking slag is discharged at temperature range between 1873 and 1923 K after discharge of refined molten steel, it also has large thermal energy. Amount of generated BOF slag is 11.0 Mt/y (FY2012) in Japan.[2] Assuming the amount of steelmaking slag is 10 Mt/y and its average heat capacity from room temperature to 1923 K is 1 kJ/kg·K,[3] unutilized heat is estimated to be 16 PJ/y, which is equal to annual energy consumption of 420 thousand families in Japan.[4]"

Jan 1, 2014