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By Timothy W. Ellis

This paper presents the basic theory of operation, physical chemistry and phase equilibria which allow the development of liquid-liquid extraction circuits based on metallic solvents. The incorporation of reduction and reduction/diffusion processes into the process 'scheme is discussed and a detailed description of ,several liquid-liquid extraction schemes are developed. A synopsis of experimental results obtained using this: method to separate rare earth and other metal based materials will be given.

Jan 1, 1996

By Wenjun Duan, Zongliang Zuo, Qingbo Yu, Qin Qin, Junxiang Liu

Moving bed has been widely used in the field of heat and mass transfer and reaction between solid particles and gas. In order to enhance the heat exchange coefficient, there will be tube banks inserted in the moving bed. In the process of drying ammoniates particles or heat recovery from high-temperature particles with moving bed, the particles flow behavior around the tube banks is significant. In this paper, the particles flow behavior around the tube banks is investigated, and all the results can provide guidance for the design and operation of a moving bed.

Jan 1, 2016

By Tianzu Yang, Weifeng Liu, Lin Chen, Qingkai Xiao, DUCHAO ZHANG

To solve the problem of low leaching ratio of direct gold cyanide leaching from arsenical refractory gold concentrate, this paper proposed a matte smelting process for gold enrichment in low grade copper matte. The effects of copper content in the mixed material, ratio change in slag type, smelting temperature and reaction time on recovery rate of gold and copper were investigated. The experimental results indicated that the recovery rate of gold increased with the increase of copper content in the mixed materials, temperature and reaction time. It was also noted that the recovery rate of gold and copper were respectively 98.16% and 96.39% when the addition of copper content in the mixed material was 3%, slag type of CaO/SiO2 and FeO/SiO2 were 0.6 and 0.9 in 1250°C and the time of reaction was 40min. Most of the arsenic was oxidized into As2O3 existed in the dust. The results showed that the matte smelting method can achieve efficient recovery of gold from arsenical refractory gold concentrate.

Jan 1, 2016

By Ting Liu, Qian Li, Peng Deng

The wastewater containing Hg2+ and Pb2+ does great harm to the environment and human bodies. Traditional wastewater treatment cannot fundamentally put a stop to heavy metals pollution for producing secondary pollution. In this paper, Hg2+ and Pb2+ in wastewater were removed and recovered by sulfide precipitation- flotation. Sodium sulfide was used as precipitant and butyl ammonium aerofloat was used as collector. Results indicated that Hg2+ and Pb2+ could be reduce to less than 0.03mg/L and 0.16mg/L respectively by both coprecipitation- floatation and fractional precipitation- floatation. In these two methods, fractional precipitation flotation could not only remove Hg2+ and Pb2+ from wastewater, but also could recover mercury and lead effectively. The infrared spectrograms showed that the adsorption between butyl ammonium aerofloat and mercury precipitate or lead precipitate is chemisorption.

Jan 1, 2015

By R. Colás, A. Salas, M. P. Guerrero Mata, R. Garza

"The use of the finite element method (FEM) for studying the plastic behavior of metals has become a common practice over the past few years, because it has been proved to be a good means of evaluating processes parameters, and predicting and improving processes, avoiding the traditional trail and error technique. FEM was used via a commercial package (Abaqus) to create two dimensional models to simulate uniaxial tensile tests for a galvanized low carbon steel. The aim of the work was to analyse the plastic behaviour of a distribution of grains on the zinc cover of a set of galvanized low carbon steel samples. A mesh with lines 2 mm apart was drawn on one of the faces of the samples that were deformed at room temperature, at constant crosshead speed, stopping the deformation at different times. Before and during the stops the deformation measurements were recorded for further calculations in an image analyser in order to compare these with computational predictions, as well as validate the numerical model. The results of this study can be extended to other testing conditions, besides the model can be used for obtaining constitutive equations of the materials.INTRODUCTIONThe use of the finite element method has been widely spread during the last two decades in most engineering areas, it is a good means of obtaining approach values at a first try [1-4]. Thanks to the software and hardware developments it is now possible to run huge problems within hours or minutes, making the technique more accessible and useful for the industry.The aim of this work is to create a finite element model for the uniaxial simple tension test, and compare the results with some experimental results, and asses the validity of the model.The plastic behaviour of the materials with FEM has been studied for a long time [5] and there is always something new to learn about this behaviour of the metals in particular, as well as to characterized new materials and alloys [6,7]. The tension test has been used since XIX century to get knowledge of the materials [5,8], it is the test that has been used the most and the only that is fully standardized, although it has the limiting of low strains, it is still the most widely used, especially in the industry.Two different finite element models in two dimensions (2D) have been developed, one called the mesh model and the other one the grain model, attention was focused on the geometry and strain prediction. The model is validated with experimental test, by using the data and directly comparing it with the numerical predictions. All the tests were carried out at the same constant crosshead speed at room temperature. An analysis of the grid distortion using FEM and analytical methods has been carried out."

Jan 1, 2001

By Lucas Barbosa de Souza Martins, Felipe Perissé Duarte Lopes, Nathalia Carneiro Garcia Rosa, Lucas Lopes da Costa, Sergio Neves Monteiro, Rubén Jesus Sanchez Rodriguez

"The fibers extracted from the stem of the banana plant are relatively stronger and have been used as reinforcement of polymer matrix composites. In addition to quasi-static mechanical properties, there is a need to characterize the dynamic behavior of banana fiber composites subjected to thermal and mechanical constraints. In this work, the temperature variation of the dynamicmechanical parameters of polyester composites incorporated with up 30% in volume of banana fibers were investigated by DMA tests. The storage and loss moduli as well as the tangent delta were measured from 20 to 200°C in a TA Instrument operated with the flexural mode at 1 Hz. The results showed that the incorporation of banana fibers tends to increase the viscoelastic stiffness of the polyester matrix. It was also observed changes in the T g and the structure dumping capacity of the composites with increasing fraction of banana fibers.IntroductionNatural fibers with high amount of cellulose, also known as lignocellulosic fibers, have been used from primeval times by our civilization. In the last century, synthetic fibers such as nylon, carbon, aramid and glass fibers gained interest owing to superior strength and precise dimensional control. Natural fibers were then replaced by synthetics in many fields such as textiles and appliances. In the past decades, however, environmental issues drawn, once again, the attention to lignocellulosic fibers as possible substitute for intensive energy-consuming and long term polluting synthetics, specially the glass fiber [1]. In particular, research works have disclosed the potential advantages associated with the use of lignocellulosic fibers as the reinforcing phase in polymer composites [2-7]. Among the advantages it is worth mentioning the renewability, recyclability, biodegradability and the fact that natural fibers are neutral with respect to C02 emissions responsible for global warming. Moreover, as compared to synthetics, lignocellulosic fibers present lower density and cost as well as reduced wear caused to the processing equipment. On the other hand, in terms of composite reinforcement, hydrophilic lignocellulosic fibers present drawbacks such as weak adhesion to hydrophobic polymeric matrices in addition to dimensional limitations and non-uniform properties."

Jan 1, 2011

By Bob Hannah, Peter C. Hayes

The changes that are happening in the world of metallurgy, and with it university education, are generational and require generational responses. Some of the key issues facing metallurgical education and ongoing professional training are explored. What will be required of metallurgical engineering professionals in the coming decades? What knowledge and skills will be needed? How to provide the educational and learning pathways, and how to attract smart young people into this profession? These are issues more readily addressed by tertiary institutions in conjunction with industry; perhaps the greater challenges lie in building and maintaining competencies post-graduation. There is a need to establish and maintain a system that supports graduates and enables them to develop further into competent expert engineers able to successfully address complex engineering challenges.

Jan 1, 2014

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

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

Jan 1, 1998

By Cleusa Cristina Bueno Martha de Souza

Nowadays in Brazil the final disposal for spent batteries include sanitary and industrial landfill for hazardous waste from domestic waste and industrial waste respectively. The problems of environmental impact caused by spent batteries had been discussed of several years, considering the fact of metals contents, like Cd, Hg, Pb and Zn. Some techniques are been proposed for recycling this type of waste in order to protect the environment while bringing also economic advantages of recovering metals. The reclamation of metals from secondary raw materials had been employed and further applications of this flexible technology are planned to the future. The processing of metals solutions involving hydrometallurgical techniques is an efficient method for recovering metals, since it provides completely recovery of metals with low energy requirements. This paper discusses the spent alkalline batteries characterization and leaching stage experiments results with sulphuric acid as leachant. After batteries dismantling by mineral processing techniques, the black powder sample produced was submitted to diffraction X-ray characterization and atomic absorption spectrophotometry in order to verify all the substances presented. Some experiments were carried on to develop a hydrometallurgical process for initial metal recovery aiming to get Zn into a soluble form on aqueous solution in order to propose the next stages of purification and recovering Zn, as electroplated deposition. The sulphuric acid was chosen not only for being cheaper than other leachants but also for improving the extraction of soluble Zn as ZnS04 form at diluted acid concentration. Batch laboratory experiments leaching procedure were conducted to determine appropriate leaching conditions from the viewpoint of maximize zinc extraction. In these tests an amount of dry powder batteries was added to different acid concentrations and solid/liquid ratio and after leaching and filtration the aqueous solutions were submitted to atomic absorption spectrophotometry analysis to verify the Zn content.

Jan 1, 2000

By Luis W. Pommier

Large quantities of sea sludge containing halogenated organic compounds, such as PCB, oils and metals like arsenic and lead have accumulated throughout the years at the bottom of sea channels and harbors and are obstructing navigation and creating environmental problems which need to be resolved. A sludge from a California port would be dredged by suction pumps, it would be processed in a plant which would be built either on firm soil or on floating platforms. The sludge shows contents of up to 1 ppm of PCB, 15 % oil and 10 ppm of arsenic, which generates a very fetid odor. Bench scale work indicates that most of the contamination concentrates on the solid phase, in fact, only minor amounts of oil report to the sea water and can be readily removed by physical means. After separation of the sea water from the solids of the sludge by decantation, it is possible to solubilize the PCB, the oil and the metals into an organic solvent leaving a non-hazardous soil for disposal near the harbor. The PCB is dehalogenated during the solubilization process leaving a liquor solution containing the oil and metals. The oil is extracted leaving an aqueous solution containing the arsenic. Further process extracts the arsenic from this solution rendering the liquid non-hazardous. Transportation and disposal of the sludge is impractical. There are hundreds of thousands of tons of hazardous soils accumulated in each harbor, which would fill the hazardous waste disposal sites available and it would be, prohibitively expensive to do so. It is not possible to compare the costs of decontamination with a competitive method. If it were, the proposed process would be less expensive than transportation and disposal and it has the advantage of removing the liabilities from the Responsible party. After a full scale continuous pilot project is run to decontaminate a small, 500 cubic yards accumulation of this type of sludge in a California harbor, a full scale environmental project would be initiated. The decontamination of one million tons of sludge would be completed in five years.

Jan 1, 1995

By R. David Prenganan

RSR has developed a new environmentally superior process to recover lead as high purity electn:1o'i0!1 cathode from battery scrap. The process involves crushing the batteries, separating the lead bearing material from the plastic, ebonite and separators, and separating the active material (paste) from the metallic lead fraction. The paste is desulfurized using Na2C03 to convert the PbS04 to PbC03 and produce a sodium sulfate solution. The paste is further treated to decompose the PbO2 and PbC03 to Pbo. The PbO from the treated paste is easily leached, using H2SiF6 and electrown from solution using Pbo2?coated graphite anodes. The electrown lead has a purity exceeding 99.99%. RSR is in the final design stages of a plant to produce 36,000 tons per year of electrcwon cathode from battery paste in a new plant adjacent to the present Indianapolis refinery. This paper describes the work of a pilot facility operated in the early 1980's. The paper describes the patented process in detail and compares the newly designed environmentally clean electrolytic plant to present recycling plants.

Jan 1, 1990

By Thierry De Nys

A direct leaching process of sulphidic zinc-based concentrates in aqueous sulphuric acid solutions has been developed by the V.M. R & D Department. By a very accurate control of the oxidation potential of the leach solution, this process enables a separate recovery of the zinc, copper, silver, lead and sulphur of the concentrate and makes it extremely attractive for treating more complex ores. The iron, solubilized during leaching, is eliminated out of the zinc solution by means of the V.M. goethite process. Alternative flow sheets for a conventional zinc electrolysis plant are presented.

Jan 1, 1990

By Daniel K. Kim

The charge for the copper refinery is a mixture of anodes produced at San Manuel from BHP source concentrate and copper purchased from external sources. Control of unwanted impurities in the tankhouse - is very important and beneficial. Currently available removal/recovery technologies were reviewed for the control of bismuth and antimony levels in the electrolyte. Recent studies have focused on solvent extraction (SX) technology and generated successful results for the removal and subsequent recovery of bismuth and antimony. The SX system employs the reagent, ACORGA SBX-50, in conjunction with a patented high chloride stripping system. The latter enables recycle of the eluant, avoiding the high costs associated with conventional systems, such as regeneration of resin. Concerns over potential transfer of organics and chloride ion to the electrolyte were readily addressed, solved and demonstrated using conventional, established technology. This paper describes the benefits of electrolyte purification, the flexibility afforded by the SX system, the operational practices necessary for maintaining adequate control of bismuth and antimony impurities in the electrorefining environment and possibilities for future development /exploitation of the Zeneca SX system at the San Manuel refinery.

Jan 1, 1998

By F. T. Principe

In order for solvent extraction technology to be acceptable as an alternative to existing jarosite precipitation circuits, iron must be cleanly separated and concentrated into a feed stream suitable for downstream iron by-product recovery which meets market specifications and economics. Ten years ago, significant progress was made in a joint McCill University/CANMET project that involved iron extraction with mono(2-ethylhexyl) phosphoric acid and stripping with HCI. Our iron solvent extraction research was reactivated recently by looking into this and other members of the organophosphorus extractant family. Our research focuses on the mechanisms and control of anion (SO42/CI) transport across the various phases (Rafinate/Organic/Strip), iron build-up in the strip liquor, and extractant stability/selectivity. In this paper, these issues along with some other performance parameters are discussed using data derived from an extensive search of the two commercially available and best known members of the organophosphorus family, di-2-ethylhexyl (D2EHPA) and mono-2-ethylhexyl (M2EHPA) phosphoric acid. Further in this discussion, the challenges lying ahead in the development of sx systems that overcome the deficiencies of D2EHPA and M2EHPA are outlined. In particular, the necessity of considering secondary separation technologies that can further concentrate iron values in the chloride strip liquor to levels economically attractive for the production of saleable iron oxide by pyrohydrolysis is addressed.

Jan 1, 1998

By Suresh Sundarraj

A diffusion mass transport model for predicting the microsegregation in a solidifying and coarsening dendritic mushy region of a binary alloy is presented. Two versions of this model are tested; one based on expressing the solute concentration in terms of mole fraction and the other on expressing the solute concentration in terms of mass fraction. On comparing previous model data sets and conditions, used in the analysis of Aluminum-Copper systems, a number of inconsistencies emerge. These inconsistencies are resolved on identifying a single set of data and conditions which take account of compositional density changes, "non-linear" thermodynamics and dynamic coarsening. An additional investigation is carried out to study the effect of assumed cooling mechanisms.

Jan 1, 1992

By J. R. Bhamidipati, Nagy EI-Kaddah

"Over the years, mathematical modeling has been established as a viable tool for design and analysis of melting and solidification processes. Modeling of electromagnetic casting and melting systems involves three coupled problems -- determination of the containment field, the shape of the meniscus, and the temperature field -- which have to be solved simultaneously. One of the difficulties in numerical simulation of these systems is in defining and gridding the solution domain as the meniscus shape of the liquid region is not known a priori. This paper describes a methodology for solving these coupled problems in a two-dimensional electromagnetic containment field. This method is based on the solution of the electromagnetic, free surface dynamic, and heat transfer equations in a fixed domain in computational space by mapping the physical space into an invariant computational space during the search for the equilibrium shape using a variable non-orthogonal coordinate transformation. This approach, also, eliminates the need for regridding the liquid and solid regions during phase change. This methodology is demonstrated for two electromagnetic confinement systems -- the Magnetic Suspension Melting process and the electromagnetic casting of aluminum. The model predictions are in good agreement with available data for these systems. It is suggested that the methodology presented here is likely to provide a useful tool in the design, analysis, and optimization of electromagnetic confinement systems. IntroductionDuring the past decade, mathematical modeling has emerged as a viable tool for the design, analysis, and optimization of casting and melting processes /1-2/. It is generally recognized that the usefulness of modeling to study the interplay between the various process parameters without resorting to extensive experimentation relies heavily on accurate representation of the physical phenomena in these systems. In modeling electromagnetic confinement casting and melting systems, it is important that the model address all aspects of electromagnetic field interaction with the metal, if accurate predictions are to be obtained /3/. The electromagnetic field affects the heat transfer phenomena primarily through joule heating. In addition, the electromagnetic forces play a key role in heat redistribution in the molten pool via melt stirring, and, in confinement systems, support the molten metal pool."

Jan 1, 1994

By J. T. I. Poijärvi

The smelter off-gas cleaning and the weak acid treatment at Outokumpu Harjavalta Metals Oy are presented and described in this paper. The smelter consists of the copper and nickel smelters and the acid plant of three separate acid plants two of which are double contact and one single plant and of one liquid sulphur dioxide plant. The preliminary cooling and flue dust separation of the smelter off-gases from the copper and nickel flash smelting furnaces and converters in the waste heat boilers and in the hot electrostatic precipitators are described. The final cooling and cleaning of the gases in the scrubbers at the sulphuric acid plant and the treatment of the weak acid in the vacuum and in the submerged combustion evaporators for the removal of impurities are pre¬sented as well as the treatment of the condensates from the evaporators. The attention is paid to the generation of sulphur trioxide in the smelter off-gas and to the treatment of that in the weak acid bleed-off and to the utilization of the treated acid.

Jan 1, 1992

By J. T. I. Poijärvi

The smelter off-gas cleaning and the weak acid treatment at Outokumpu Harjavalta Metals Oy are presented and described in this paper. The smelter consists of the copper and nickel smelters and the acid plant of three separate acid plants two of which are double contact and one single plant and of one liquid sulphur dioxide plant. The preliminary cooling and flue dust separation of the smelter off....,gases from the copper ?and nickel flash smelting furnaces and converters? in the waste heat boilers and in the hot electrostatic precipitators are described. The final cooling and cleaning of the gases in the scrubbers at the sulphuric acid plant and the treatment of the weak acid in the vacuum and in the submerged combustion evaporators for the removal of impurities are presented as well as the treatment of the condensates from the evaporators. The attention is paid to the generation of sulphur trioxide in the smelter off-gas.and to the treatment of that in the weak acid bleed-off and to the utilization of the treated acid.

Jan 1, 1992

By V. P. Bystrov

Vanyukov process has been developed and investigated in Russia over the last 25 years. It has been established that various kind of material could be treated in Vanyukov process. The results of the pilot plant trials as well as industrial experience are presented in this paper.

Jan 1, 1993

By C. J. Newman

In January 1999, a redesign of the Kennecott Flash Converting furnace settler was initiated to enhance furnace integrity and extend furnace life. This furnace uses Kennecott-Outokumpu Flash Converting technology to produce copper directly from copper matte. A detailed assessment was made of all technology available around the world before making a decision on the design features to be incorporated in the new design. The new design includes the following: redesign of all sidewall cooling elements to include the latest cooling element technology; redesign of the furnace hearth to include a stadium hearth at the reaction shaft end of the furnace; redesign of the furnace hearth to include a stepped hearth design adjacent to the furnace sidewalls; addition of flat settler roof cooling elements .around the reaction shaft; replacement of reaction shaft transition elements with an improved design and improvements to the furnace cooling element monitoring systems. The Flash Converting furnace was shut down on a planned basis in July 2001 to implement these improvements after 29 months of operation, converting more than 1,000,000 tonnes of matte. During the 30 day shut down, the improvements were successfully completed, with furnace start up in August 2001

Jan 1, 2002