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By Benoit DeBecker

Laboratory-scale experiments have shown that chromium metal could be recovered from chromate wastes by modifying slightly the chromium electrowinning flow-sheet. After reduction by sulhr dioxide and precipitation of chromic hydroxide, the solid residue is dissolved in the chrome alum solution and the metallic impurities are removed by cementation on manganese. The presence of dissolved manganese in the electrolyte does not affect the cathodic deposition of chromium and it eliminates the anodic production of Cr(V1).

Jan 1, 1994

By Bradford C. Wesstrom

The extraction of metals from Copper Refinery Slimes may involve many different processes. This paper describes the use of pressure leaching for decopperizing of copper refinery slimes at the El Paso Refinery. Process equipment will be described, along with the process chemistry, unit operations and unit processes associated with the decopperizing process. Copper contained in the raw slimes ranges from 15-35%. After autoclaving less than 1 % copper remains.

Jan 1, 2000

By Jin-tao Gao

In order to recover Ti resource from titanium bearing blast furnace slag, a new technology to separate perovskite phase from CaO-TiO2-SiO2-Al2O3-MgO system by supergravity is researched. In the condition of gravity coefficient of 750g, treatment temperature of 1305°C and time of 20min, the significant layers appear in samples which are obtained by means of centrifugal treatment. Along the direction of the supergravity, the volume fraction of perovskite phase increases gradually, and the equivalent diameters of perovskite phase crystals increases with the area approaching to the bottom of the sample. It is indicated that TiO2 is enriched in the bottom of sample as concentrate with a recovery ratio of 74.05% by supergravity treatment.

Jan 1, 2014

By Chunhua Liao, Chao Peng, Guangsheng Huo

To get the separation of tungsten and molybdenum, we adjusted the pH of the solution to 7, at which tungstate (WO4 2-) will be polymerized into HW6O21 5-, while molybdate will still exist in the form of MoO4 2-. Two strongly basic anion exchange resins (D201, D213) were experimented for the separation of tungsten and molybdenum. The results of condition experiments indicate that D213 resin performs better in the treatment of lower concentration solution A (WO3 10g/L, Mo 4.12g/L) with a separation factor as high as 10.64. While D201 resin is more suitable for the high concentration solution B (WO3 70g/L, Mo 28.97g/L) with a separation factor of 6.9. The results of column testing performed on D213 resin show that the solution after loading process with a mass ratio of Mo/WO3 = 50 and the desorption solution with a mass ratio of WO3/Mo = 27 can be obtained

Jan 1, 2014

By T. Mason, R. Macko

Electroless nickel (EN) coatings are widely used in the manufacture of automotive parts, providing uniform coating, corrosion protection, wear resistance and lubrication. In contrast to EN plating benefits, the disposal and treatment of waste solutions can cause many difficulties. The use of electrochemical treatment technology greatly improves _the operation of the main wastewater treatment process and reduces operation costs. A new, state-of-the-art job shop in the Chicago area, which provides EN plating for the automotive industry, has installed a large separated electrolytic cell for the treatment of spent EN solution (from dumps and wastewater). The waste/wastewater is handled by the separated electrolytic cell, batch treatment system, filter press and neutralization station. The implementation of modem electrolytic technology and auxilliary equipment provides an effective waste treatment process that meets environmental compliance criteria.

Jan 1, 2000

By Atsuhiro Nabei, Ken-ichi Yamaguchi

"Wet chlorination process of de-copperized anode slime is followed by de-chlorination stage in which lead-sulfate and metallic silver form silver residue. The silver residue is subsequently reduced to Ag2Se matte and PbO-SiO2 slag to remove lead to the slag in a short rotary furnace. Although this smelting process is proven well in actual operations, few papers have investigated its metallurgical aspects. This paper will describe the effectiveness of controlling parameters adopted at the Naoshima Smelter & Refinery and discuss the decisive factors influencing silver loss to PbO-SiO2 slag.IntroductionThe precious metals plant at Naoshima smelter & refinery was established in 1989, and has produced electrolytic silver, refined gold and platinum-group metals (PGM) from de-copperized anode slime as by-products of electrolytic copper. The process for gold production has been innovated from conventional smelting process to hydrometallurgical process since 2004 [1], while the process for silver production has still remained the same.The process for silver production at the Naoshima smelter & refinery is illustrated schematically in Figure 1. De-copperized anode slime is, at first, concentrated in the froth flotation process, then leached in the wet-chlorination process, and converted to silver residue in the de-chlorination process. The silver residue, which is a mixture of lead-sulfate and metallic silver, is charged to a short rotary furnace for the oxidation roasting to volatilize selenium dioxide and subsequent reduction smelting. In the smelting stage, silver residue and reverts containing selenium are smelted with flux and carbonaceous materials to form PbO-SiO2 slag and Ag2Se matte. Furthermore, Ag2Se matte is transferred to a rotary cupell and oxidized by air with the addition of sodium carbonate and sodium nitrate to produce silver anodes while removing impurities into litharge. Silver anodes are electrolytically refined by the Moebius process. Electrolytic silver is washed, dried and, finally, cast into 30kg-bars."

Jan 1, 2011

By A. Rawat

The removal of oxyanions of arsenic present in mine process water and drinking water to a regulatory level is a challenging problem. Recently a patented adsorbent lanthanum oxide has been developed which has shown strong specificity for the anions of arsenic. In this paper the kinetic and thermodynamic aspects of arsenic adsorption on to lanthanum oxide are discussed. Adsorption tests were performed at different temperatures using synthetic solutions of arsenic of varying concentrations. From the kinetic data and adsorption isotherms thermodynamic properties such as Gibb's free energy, standard enthalpy of adsorption, standard entropy, isosteric heat of adsorption and activation energy were determined. The results showed that temperature had a positive effect on the rate and degree of adsorption:The activation energy decreased with increase in the initial concentration thus indicating solute-solute interactions in the system. Also, the isosteric heat was found to decrease with increase in the adsorption density implying a heterogeneous adsorbent surface.

Jan 1, 1998

By Bhagyadhar Bhoi, Chitta Ranjan Mishra, Hara Prasanna Mishra

"In the Sukinda Valley of Orissa, India, the total quantity of nickel ore reserves comprising of both lateritic and chromite over burden(COB) have been estimated at around 231 million tonnes containing 0.3 to 0.9% Ni. While mining of one tonne of Chromite ore, around 6-7 tonnes of chromite over burden are removed. These overburden materials are disposed as waste materials, which causes lot of environmental hazards and ecological imbalance. India imports a large amount of nickel and ferro-nickel to meet its growing demands in various sectors. For import substitutions, efforts have been made to produced ferro-nickel from the lean deposits of nickel bearing lateritic ores/ chromite over burden materials by reduction roasting followed by magnetic separation and then the nickel rich magnetic fraction is smelted to produce ferro-nickel. It has been possible to produce ferro-nickel of grade varying from 4-25% nickel.IntroductionDuring mining of chromite ore, large quantities of overburden materials are being generated. The materials amount to approximately 10 million tones per year contain around 0.3-0.9% Ni, 0.02-0.06% Co, 20-50% Fe and 4-9% Cr2O3 depending upon the location and the depth of the mine. These materials presently do not find any application for the extraction of nickel due to lack of a suitable technology. The materials are also unsuitable for ferro-nickel making because of their very high iron to nickel ratio. The country is seriously looking for a suitable technology to utilize these resources as its entire domestic requirements of nickel is met though imports. In this connection, a systematic approach has been made at the Institute of Minerals and Materials Technology, Bhubaneswar to develop a process for ferro-nickel making from this indigenous resource."

Jan 1, 2011

By Bernd-Arno Behrens, Klaus-Georg Kosch

"In times of increasing energy costs automotive lightweight construction is gaining in importance. This paper deals with the production of hybrid steel-aluminum compounds by forging. The compound forging process is a promising method to successfully manufacture functional parts by applying resource-saving process steps. Nevertheless, challenges resulting from different material properties must be solved.The heating of hybrid material work pieces made of steel and aluminum is a great challenge. Steel is forged at a temperature of at least TSt =900 °C, while aluminum should not exceed a temperature of TA1= 500 °C. For achieving the required temperature gradient extensive experimental investigations have been carried out. Intermetallic phases form during the manufacturing process and can influence the bonding and the global part quality. In addition, methods for the characterization of the joining zone between the materials steel and aluminum are analyzed and the factors influencing the formation of intermetallic phases are determined experimentally.IntroductionIn times of increasing energy costs and stricter conditions relating to environmental protection, automotive lightweight construction is gaining in importance. The production of hybrid compounds by forging is a promising method to manufacture functional parts by applying resource-saving process steps. In compound forging a hybrid raw part consisting of a solid core, which is enclosed by a hollow casing, is joint in the forming process. This results in a graded material structure in the part in which the mechanical properties can be specifically adapted to the requirements. Compound forging is the form joining and/or firmly bonded joining of at least two different materials while plastic shape forming occurs (Figure 1)."

Jan 1, 2012

By Huayi Yin, Wang. Dihua, Wei Xiao, Xuhui Mao, Diyong Tang

"The world production of crude steel reached 1.55 billion tons in 2012,which generated ~2.5 billion tons of CO2. Electrochemical metallurgy especially through high temperature molten salt electrolysis with renewable electricity stands for a great opportunity for producing “green” metals. In recent years, electrolytic production of iron without emission of CO2 in different molten salt systems has been reported. A cost-affordable inert anode is the key to produce acceptable eco-friendly iron by the novel molten salt electrolysis processes. Based on the authors’ research, this paper will discuss iron production by molten salt electrolysis using a nickel alloy inert anode. On the other hand, the paper also covers a novel molten salt CO2 capture and electrochemical transformation (MSCC-ET) process, in which CO2 is effectively converted to value-added carbon and oxygen in a molten bath using a cost-affordable nonconsumable SnO2 anode.1. IntroductionEnergy and materials are cornerstones to support the development of human society. The traditional primary metal production, especially iron and steel, and electricity production are mainly based on the reactions between carbon (coal) and oxygen (represented by equations (1) and (2) respectively), which produce huge amount of CO2.MxOy + 0.5y C = x M + 0.5y CO2 (g) + Q1 ( 1 )C + O2 (g) = CO2 (g) + Q2 ( 2 )In 2012, the world production of crude steel reached 1.55 billion tons, of which 46.3 %, ~0.7165 billion tons were produced in China. Based on the average level of 1.7t CO2 emission per ton steel, more than 1 billion tons of CO2 generated from steel industry in China in the year. Besides the iron and steel industry, thermal power plant leads the CO2 emission in both USA and China. The total consumed electricity in China increased to 4959 billion kWh in 2012, ~70% of it was from coal fired power plant. The average CO2 emission for electricity production in the typical thermal power plant in China is around 0.78 kg kWh-1. It accounts for ~ 3.868 billion tons of CO2 emission from thermal power plant in 2012 in China."

Jan 1, 2014

By Z. Smieszek, W. D?browicz, J. Pawlowski, G. Krawiec, J. Czernecki, J. Por?mbski, S. Gizicki

Rapid development of the automotive industry and motorization has been observed in Poland over the last decade. This phenomenon has increased the amount of used car batteries requiring recycling and has thus posed new challenges for their processing. Orzel Bialy" S.A, is the major secondary lead smelter in Poland. Ibis paper describes the program for smelting technology modernisation and productivity increase through the application of oxy-fuel burners, which has been implemented at "Orzel Bialy'' S.A. The main objective of smelter modernisation, which was to increase the furnace productivity by 20%, has been achieved. This paper outlines the previous and present state of the lead acid battery scrap smelting technology at the "Orzel Bialy" S.A. Specifications of the burners and of oxygen installation are given. Industrial tests with the modernised smelting technology and optimisation of the process parameters are described, and the results obtained are discussed.

Jan 1, 2000

By M. Waladan

The top submerged lancing Sirosmelt system has been developed through laborator.y scale testwork and pilot plant trials for recovery of zinc from ISF slag. The effects of the process variables of gas injection rate, method of coal feeding, and temperature on zinc fuming rates were studied in the laboratory. It was found that the rate of zinc elimination was dependent on all of these variabl.es. The rate of zinc removal from slag was independent of zinc content of slag down to approximately 1.5% Zn, below which the rate was proportional to zinc content in slag. Pilot plant trials were carried out to evaluate a proposed process and results followed predictions from the laboratory scale tests. A comparison of the proposed process with conventional slag fuming operations is made and it is shown that the process has a number of advantages which have a significant impact on the economics of zinc slag fuming.

Jan 1, 1990

By Federico Chavez

The process for recovering lead from battery residues used in several Mexican Plants include lead blast furnace and rotary furnaces. The formers are basically fed with recycled batteries together with the necessary additives to produce metallic lead. One of the by-products generated in the blast furnace is a dust mainly formed by lead sulfide. The rotary furnace is used to recover lead .from lead batteries, dross from the refining-alloying process and the leady fines produced in the blast furnace. This paper describes thennodynamic analysis made to the rotary furnace process to understand the effect that each component of the system has upon the lead recovery. In order to enhance the process, the influence of iron chips composition and excess coke on slag viscosity is discussed. A computer optimization program . has been developed to design the furnace charge based on material and energy balances, .together with the thennodynamic equilibrium calculation.

Jan 1, 1995

By K. Osseo-Asare

It is possible to form a two-phase system in certain polymerlinorganic salt/water mixtures, such as those containing the polymer polyethylene glycol (PEG). Such aqueous biphase systems have many of the separation characteristics of conventional solvent? extraction systems, but are environmentally friendlier. Just like the well-known organic solvent/water two-phase system, the top polymer-rich phase is more hydrophobic. and the bottom salt-rich phase more hydrophilic. The partition of dispersed? particles is dependent on the interfacial interaction between the particles and the conjugate aqueous biphase solutions. In particular, the hydrophilic/hydrophobic properties of the surface determine the transfer of the dispersed particles into either the top (more hydrophilic) phase or the bottom (more hydrophobic) phase. Accordingly, differences in the surface chemistry of particles can be exploited to achieve selective separations. In this work, several approaches to separation control will be discussed. using pyrite (FeS2), alumina (AI203). hematite (Fe203), silica (Si02), and titania (Ti02) as model particulate materials. For metal sulfides, pH and redox potential can be used to alter the hydrophobicity/hydrophilicity of the particles. In ?the case of oxides. polymer adsorption and collector adsorption may be exploited to facilitate particle transfer.

Jan 1, 1999

By Andres Vikdahl

The Rönnsktär smelter has recently undergone a series of technical and operational changes. This changes are caused by our own will to remain and gain in competivety and to adapt to the ever changing surroundings. To be able to remain competitive in surrounding with high wage costs, high inflation and high environmental standards thorough cost management is needed. The Swedish economic policy in the beginning of the 80'ies consisted amongst other things of two devaluations. The exchange rate of the Swedish Krona was reduced with approximatively 25 %. This boosted the profits of our export industry, some even believed we entered the land of milk and honey ... And working in this promised land where everything turns into profit it is very difficult to be careful and restrictive with your spendings. Apart from some healthy and fruitful investments we allowed ourselves yearly steady increases in salary for ever reduced number of worked hours and we of course employed more people. Inflation rates went up and so did property prices. In 1986 finally reality catched up on us. Reality in the form of too high costs started to hit Swedish export industry 5-6 years after the big devaluations. Furthermore the high inflation rate also hit the domestic industry a couple of years later. Together with other important factors Sweden faced a severe home-made recession in the beginning of the 90'ies. With this background we now report and analyse our smelter's performance and operating results, shown in fig 1 The main constrictions on smelting and refining at Rönnsktär are today: * Income restrictions by governmental production level Limit * Throughput resmctions by governmental emission limit * High capital costs in the aftermath of Swedish high inflation in the recent decade * Low work force turnover Below we will illustrate how we tackled with these issues along the following lines: * People * Quality * Technology

Jan 1, 1993

By Jorge Alberto Soares Tenório, Denise Crocce Romano Espinosa, Viviane Tavares Moraes

"The development of mobile phone technology has increased the replacement of outdated equipments for more modern models, transforming disposal of such devices into a serious environmental problem. Recycling appears as an attractive alternative to minimize the environmental impact of disposing such large quantities. Recycling can be accomplished by treating the printed circuit boards of used mobile phones by using the same techniques used in ore treatments with hammer mill; magnetic separation, electrostatic separation and grain size range. Before performing the recycling process a PCB characterization was performed to identify the fraction with the higher metals concentration/content. This study demonstrated that the electrostatic separation was not the best metals concentration of PCB aiming the recycling, while the non-magnetic residue had presented a more significant metal concentration. Furthermore, after the magnetic separation was possible to separate the following metals: iron and nickel.IntroductionPortable electronic devices have gained increasing acceptance over the last decades. Mobile phones sales in Brazil, for instance, have reached 104 million in 2007, and 128 million in 2008. It is estimated that, around the world, 100 million mobiles are thrown away every year, either because of loss of functionality or because newer models are launched in the market [1,2, 3]. Printed circuit boards in mobile phones are made of many materials, with approximately 83% in weight being metals and fiber-glass, and the balance being plastics pl. Several metals can be recovered from the electronics waste, such as copper, tin, iron, lead, nickel, titanium, aluminium as well as some precious metals such as gold, silver and palladium [4, 5, 6, 7, 8]. Concurrent with the increasing world demand for copper, there average metal content in ores has been decreasing. Economically interesting copper mines used to have 4% metal content, whereas presently, such content is around 1%, i.e., for every 1 ton of ore extracted, only 10 kg are copper [9, 10]. Approximately 33% of printed circuit boards (PCBs) composition is copper, that is, for every 1 ton of PCBs waste, 330 kg are copper [1]. Research in recycling PCB waste focuses on mechanical, electrometallurgy, pyrometallurgical and hydrometallurgical processes [3, 8]. Collecting and recycling obsoletes electro-electronic equipments is very important these days, in order to, not just preserve the non renewable natural resources but also to keep the environment and the population safe from the pollution caused by the toxic materials and heavy metals present in this kind of waste."

Jan 1, 2011

By M. S. Moats

Galvanic stripping, in conjunction with solvent extraction, has been proposed as a technical option to the challenging problem of iron removal in certain hydrometallurgical processes. The galvanic stripping process is based on the ability of a solid metal to directly reduce ferric ion to the ferrous state in an organic media. Stripping the iron into the aqueous phase is then easily accomplished. Previous work has shown the reaction kinetics and efficiency are affected by such operating parameters as water and oxygen contents, temperature, time and metal reductant. In this study, the optimum operating range for some of these variables was determined. Both zinc and iron metal were used in the separate stripping of iron from D2EHP A. Reasons for the differences in the extent of the reaction obtained using the various conditions are discussed.

Jan 1, 1996

By Z. Q. Chen, M. H. Loretto, Y. G. Li

"As-cast, As-forged, as-solution-treated, and solution treated and aged microstructures of Ti-15Mo (IMI205) with and without carbon were examined using optical microscopy, scanning electron microscopy .and transmission electron microscopy. Tensile testing was carried out at room temperature. It was found that carbon acts primarily as a titanium carbide former: Titanium carbides increase slightly the tensile strength, but decrease the ductility of IMI205. These observations are interpreted in terms of the titanium carbide morphology observed using SEM and TEM and the phase diagrams of Ti-Mo, Ti-C, and Mo-C.IntroductionIn a recent study on the development of a burn-resistant 13-Ti alloy, carbon was introduced· into the Ti-V-Cr system in order to optimise the mechanical properties. Research results[1, 2] demonstrate that carbon addition can refine the 13 grain size and improve the stability of the 13 phase in Ti-V-Cr alloys. The most attractive result is that carbon addition produced a marked improvement in the ductility of alloys when the carbon content is over 0.1 wt.% in this alloy system. Even after long exposure, the alloy with carbon addition maintains good ductility. One of the main reasons for the ductilising of the alloy is that titanium carbides can getter the oxygen from the 13 matrix.In view of the success of carbon addition in improving the properties and the stability of the Ti-V-Cr alloy, it is of interest to investigate the behaviour of carbon addition in other beta Ti-base alloys. The objective of the present work was, therefore, to assess the microstructures and mechanical properties of IMI 205, a metastable beta titanium alloy, with and without carbon addition using optical microscopy (OM), scanning electron microscopy (SEM), transmission electron microscopy (TEM), wavelength dispersive X-ray (WDX) analysis, room temperature tensile testing."

Jan 1, 2000

By Geoffrey A. Brooks, M Akbar Rhamdhani, Md Saiful Islam

A novel electrically-enhanced metal purification using slag has been developed. This was achieved by applying DC potential between liquid metal and slag phases. The concept was demonstrated through small-scale experiments at temperatures of 1500-1600oC for the removal of boron from Si-B melt using CaO-SiO2-16wt%Al2O3. Silicon (containing B) and slag were reacted in an alumina crucible in a resistance tube furnace. A circuit was produced by immersing graphite rods into the silicon bath and the slag layer. Electrical potential differences of up to 3.5 V were applied during the reactions. The reaction rates, the opencircuit voltages and short-circuit currents (in the case when the potential was applied) were then measured and determined for various slag to silicon ratio. It has been shown from this study that both the apparent rate and the boron partition ratio were increased by a factor of approximately 1.6.

Jan 1, 2014

By E. B. Zanelato

The process of casting metals and alloys occurs through the fusion of this metal and its subsequent casting into a mold with the dimensions and geometry close to the final piece. Most foundries use sand casting molds for making you. This work aims to characterize and evaluate the foundry sand to allow its use in segments of Civil Engineering, creating a viable destination for a residue is that discarded. The following characterization tests were performer: particle size, chemical analysis, X-ray Diffraction and Density Real grain. For the execution of the test specimens was used to 1:3 cement and sand, and the incorporation of 10% and 20% of the total mass replacing the sand, and the trace reference. The results show that best results in compression and bending tests were obtained by replacing 10 % of common sand for sand casting.

Jan 1, 2015