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By Shaohua Ju, Feng Jiang, Chuanhua Li, Jinhui Peng, Libo Zhang

A T-junction microchannel is proposed to overcome the existing problems in conventional solvent extraction of indium from zinc hydrometallurgical process. Experiments were performed to separate In3+, Fe3+ and Zn2+ from sulfate solutions using Di-(2-ethylhexyl)phosphoric acid (D2EHPA) as the extractant. The effect of parameters such as pH, microchannel size and contact time on the extraction behavior of In3+, Fe3+ and Zn2+ was investigated. At contact time of 2.52 s and initial solution pH of 0.48, the extraction efficiency of In3+, Fe3+ and Zn2+ was 99.13%, 8.31% and 2.45%, respectively and separation factor of In3+/Fe3+ and In3+/Zn2+ were almost 1229.54 and 4864.98, respectively. Then, the loaded organic phase was stripped in T-junction microchannel. At contact time of 33.6 s, 99.64% of stripping efficiency of In3+ and stripping equilibrium were reached, while concentration of Fe3+ and Zn2+ was lower than 0.01 g/L with good separation of In3+ from Fe3+ and Zn2+.

Jan 1, 2016

By G. Bjorling

After complete dissolution of chalcopyrite concentrate in sulphuric acid in presence of nitric acid the excess of the latter is expelled by a surplus of concentrate and the last traces of nitrate removed in the mother liquor after crystallization of the copper and iron sulphates. Zinc accumulates in the mother liquor from which it can be removed by solvent extraction of zinc sulphate as a pair of ions. After dissolution of the sulphate crystals in water the neutral solution is oxidized in an autoclave at 140°C where iron sulphate is thermally hydrolyzed; the iron-free solution is taken to copper electrowinning and the cell acid after partial evaporation recirculated with the mother liquor to the leaching circuit. Total recovery of copper is about 96%; other metals like zinc and iron are concentrated in industrially usable products. At a copper price of about 70 c/lb, the method appears to be profitable also in a small unit.

Jan 1, 1976

By F. F. Lins

There is a large use of mercury in Brazil by the gold miners in the so called "garimpos" (non registered mining operations), where it is usual to recover the gold contained in the gravity concentrates by amalgamation, which is highly deleterious to environment if not conducted properly. Unfortunately, this is a common practice there. After presenting in brief the modus operandi generally practiced in the garimpos and the environmental problems, this work reviews some of the research conducted in CETEM according to two approaches: (i) replace amalgamation by other processes and (ii) develop technology to treat mercury-contaminated soils and effluents. Conventional processes like froth flotation, to recover gold from gravity concentrates, and centrifuges were considered. Also as alternatives to amalgamation, innovative process like the recovery of gold by coal-oil agglomerates and a technology that is currently under development in our laboratory, called gold-paraffin process, are described in brief, some results presented and their potential use assessed. To reclaim sites already polluted a technology was developed to float mercury selectively from contaminated soils. The potential use of centrifuges to pre-concentrate the mercury is also discussed. The scope for applying the last techniques is to concentrate the pollutants in a small volume of mass which would be suitable for recycling or isolation from the environment. A prospective technology to treat contaminated soils, or mercury concentrates, is the immobilization of mercury by adding inorganics. Concerning the ionic mercury which may be present in effluents, precipitation of the ions and flotation of the precipitates are being studied.

Jan 1, 1994

By M. Rubinstein, N. C. Koon, B. N. Das, V. G. Harris

"Copper and gold - based alloys having giant magnetoresistance properties were produced by melt spinning from arc melted and cast rods. The ribbon width varied between 1 and 2 mm and the ribbon thicknesses were in the range of 30 to 50 11m. The uniform microstructure of the cast rods indicated the composition homogeneity in the starting material. The ribbons showed composition uniformity across the cross section from EDX analysis. However, the spun ribbon microstructure changed from a 'frozen in' region near the wheel side to a nanosize spherically precipitated phase towards the freely frozen surface. The evolution of the microstructure from the spun ribbon state to the annealed ones was studied by optical microscopy, SEM and TEM. The structural information of the spun and annealed specimens was obtained from X - ray, electron diffraction, electron microscopy and ferromagnetic resonance. Magnetoresistance was measured by the four point probe method.IntroductionRecently. Giant Magnetoresistance. GMR. has been observed in sputtered thin films alloys of Ag. Au and Cu with Co and Fe [1. 2. 3]. The sputtered films are produced by condensation of the alloys from the vapor phase. These Ag. Au and Cu alloys are miscible and homogeneous in the vapor and liquid phase (except Ag alloys which exhibit phase separation even in the liquid phase) but immiscible and heterogeneous in the solid phase. In our work we have produced thin ribbons of the Cu and Au alloys about 30 µm thick from the miscible state in liquid phase by rapid solidification melt spinning. The microstructural development of the ribbons was investigated in the as - spun condition and on annealing. The other properties such as magnetization. GMR and Mossbauer Spectroscopy were also investigated in the various microstructural conditions of the ribbons."

Jan 1, 1994

By A. Patti, S. Reutzel, D. M. Herlach, L. Ratke, I. Egry

Cu-Co shows a metastable miscibility gap in the region of the undercooled melt. Undercooling of the melt below the binodal leads to separation of the melt into a Co-rich LI-phase and a Curich L2-phase. Experimentally, undercooling into the metastable miscibility gap is realised by means of electromagnetic levitation (EML), processing in drop tube (DT) and by melt flux embedding. As undercooling is large in these experiments, the velocity of the solidification front is high and the microstructure is frozen in instantaneously. Samples have been undercooled and solidified in the TEMPUS-facility (container less electromagnetic processing under weightlessness) during parabolic flight under reduced gravity conditions. Microstructures of solidified samples have been analysed and compared to those processed under gravitational conditions. The influence of convection on phase growth is much lower in reduced gravity. The microstructure shows spherical droplets of the minority phase, statistically dispersed in the majority phase.

Jan 1, 2004

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 Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Pinakin C. Chaubal

Today?s steel industry is in a vibrant and resurgent mode. This transformation has been in the making for some time now. Over the last few decades, the industry was steadily transforming itself into becoming a high tech industry. New technology was adopted, efficiencies were enhanced, lean manufacturing concepts were brought in and a strong customer focus was developed. Today?s mills employ sophisticated instrumentation, computerized monitoring, on-line smart systems etc. driving processes that are producing at rates of many tons/minute. All this is not possible without judiciously using the latest available technologies in various fields and developing a more sophisticated work force. Prof. Sohn has been a pioneer in driving the concept of process engineering in process metallurgy. In this paper the focus is on some aspects of process engineering ? primarily process modeling - as applied to iron and steelmaking processes. Examples are shown to demonstrate how problems have been addressed. Some thoughts on future directions are presented.

Jan 1, 2006

By Hye-Sung Kim, Dong-Wha Kum, Gyeungho Kim

"Mechanical alloying is an effective way to finely distribute inert dispersoids in AI-TM (TM is a transition metal element) systems. It is considered that high melting point aluminides are formed by precipitation from the supersaturated aluminum matrix. The analysis is based on the fact that much higher content of TM than the solubility limit can be dissolved in alpha aluminum during the high energy ball milling. Nonetheless, the role of undissolved TM particles affecting the formation of aluminides is not suitably considered. In this paper, authors present experimental observation on the formation of Ab3Ti particles from mechanically alloyed AI-Ti alloys in the hyper-peritectic region. This study showed that, in the mechanically alloyed AI-20wt%Ti specimen, intermediate phase of cubic Ab3Ti and tetragonal AIz4Tis formed at 300 - 400°C and 400 - 500°C, respectively, before the MA-state reaches to the global equilibrium at higher temperatures. The formation behavior of Lh- Ab3Ti is interpreted by interdiffusion of Al and Ti in solid state based on the fact that large amount of nano-sized Ti particles exist in the milled powder. Present analysis indicated undissolved Ti particles of nanosize should have played an important role initiating the formation of Ab3Ti phase during annealing.IntroductionInterest in the hyper-peritectic AI-Ti alloys is based on industrial demand for high-modulus and high-temperature aluminum alloys. Earlier works on hyper-peritectic AI-Ti alloys with 4 to 12wt%Ti show that these alloys are strong at ambient temperature and maintain high strength above 300°C when titanium-trialuminide (e.g., Ab3Ti) is finely distributed in the aluminum matrix [1,2]. High melting point and high stiffness with low density of AbTi make the AI-Ti alloys strong with greater thermal stability while keeping weight savings as much as possible. Titanium in aluminum shares other merits of transition metal additions because Ti solubility in Al is low (i.e., 1.l5wt%Ti at 665°C and virtually zero below 400°C), and fine dispersion of Ab3Ti particles is readily accomplished and resists grain coarsening effectively."

Jan 1, 1996

By Asok Kumar Das

"In steel making ferroalloys occupies a commanding role for production of varied quality of steel. Ferroalloys enable alloying elements such as chromium, silicon, manganese, vanadium etc to be safely and economically introduced into metallurgical processes thus giving certain desirable properties of the alloyed metal. Their importance grew with the progress of the steel metallurgy which implied more diversified alloying elements, in better controlled quantities, in purer steel. The ferroalloy industry became a key supplier to the steel industry. Production of ferroalloys generally involves the use of Electric Arc furnace(EAF) into which raw materials(e.g. various metal ores, quartz, coke, lime etc ) with relatively fluctuating physical compositions are loaded. Due to this, one of the major environmental impacts of producing ferroalloys is the emission of dust and fume from the smelting process. INTRODUCTIONFerro Alloys are essential ingredients used for refining, de-oxidation, desulphurization and alloying addition in the production of different types of steel and hence Ferro Alloy industry forms a back bone of iron and steel in the world. Indian ferro alloy industry is more than 45 years old. It produces most of the bulk ferro alloys and a large number of special ferro alloys. The present installed capacity of the Indian ferro alloy industry is sufficient to meet the requirement of existing level of indigenous steel production of about 46 million tonnes. Revised National Steel Policy – 2008 envisages production of more than 100 million tonnes of steel by the year 2011-12, at proportionate annual growth rate per annum. The focus of the policy is to achieve global competitiveness not only in terms of cost, quality and product-mix but also in terms of global benchmarks of efficiency and productivity. In order to achieve the objectives of National Steel Policy and also to meet the requirement of ferro alloys, the Indian Ferro Alloy Industry has to gear up in terms of enhancement in production capacity, sourcing of raw materials, up gradation of technology, improvement in productivity, automation / mechanization, customer satisfaction etc."

Jan 1, 2008

By Xiangru Chen, Qijie Zhai, Haicheng Li, Chao Yang, Zhang Wei

The Nb-rich phase generated by the addition of trace amounts of Nb(<0.1wt%) \ and the effects of different content of Nb on the morphology and distribution of graphite in ductile iron were studied in this paper. The results showed that when the content of niobium less than 0.1wt%, the two-dimensional morphology of Nb-rich phase existed in microalloyed ductile iron were mainly regular pattern such as square, triangle, polygon etc. Besides, Nb-rich phase in large size distributed in the matrix with a certain distance from graphite. With the increasing amount of niobium, the dispersion degree of graphite diameter, average diameter and roundness increased slightly, and the number of graphite decreased slightly.

Jan 1, 2015

By Yonggang Liu

Microstructure and precipitates in hot rolled low carbon steel sheet by CSP were investigated in this paper. It is pointed out the precipitates in low carbon steel sheet by CSP are different with that by traditional hot rolling. The bainites were found in CSP hot rolled steel sheet by TEM testing and these bainites could maintain in the sheets even after batch annealing. The selected area electron diffraction analyzing indicated that there were many CrB2BN and FeB4BN phases precipitated in hot rolled steel sheet and no AlN grains precipitated. The nitrides forming can limit AlN grains precipitating during the batch annealing processing, and this could do harm to the texture pipeline along orientation line forming with formed properties.

Jan 1, 2006

By H. C. Roland Kammel

Stannous sulfate electrolytes are widely used nowadays in electrolytic tin production. Characteristic features of this electrolysis process are that dense cathode deposits can only be obtained by additions of organic additives and that so called ?black mud is formed on the anode surface which leads to an increase in cell-voltage. In order to prevent excessive cell-voltages or oxygen evolution the black mud has to be removed periodically. Studies in laboratory scale have been performed about the effect of different organic additives on electrolytic tin deposition and the formation of surface layers on pure and industrial tin anodes. Results reveal that organic addition agents are effective in reducing cathode roughening as well as extending the covering time of the anode ?by black muds.

Jan 1, 1985

By Eric J. Beckman

Recovery of metals from dilute solution, whether the matrix is solid, or liquid, remains a considerable technical and financial challenge. Methods currently exist whereby metals can be extracted from either type of matrix, yet these methods consume significant quantities of reagents and can also generate multiple waste ,streams in the process. Technology developed in our lab allows efficient application of environmentally-benign CO2 to a number of separation problems involving metals. For example, we have employed biphasic mixtures of C02 and water as a green acid leach medium. Metals have been extracted from a steelmaking process residue and then recovered as metal carbonates through depressurization. In this process, metals are extracted and recovered without the use of reagents other than CO2 and water, and CO2 is sequestered as a solid. In addition, through synthesis of Cal-miscible phase transfer agents, we have shown that CO2 can replace the organic solvent currently used in refining of precious metals, The sensitivity to pressure of phase behavior in a CO2-mixture may allow significant streamlining of the process as well. Finally, CO2 soluble chelating agents have been used to extract toxic metals from acidic effluent such as that found in plating facilities.

Jan 1, 1999