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By Santhanam Ramesh

"The shell (exoskeleton) waste of shellfish such as shrimps and crabs is the raw material in the extraction of chitosan, a polymer. Chitosan has several medicinal values such as reduction in cholesterol, urea and creatine in the blood. It is estimated that about 40000 tonnes of chitosan may be obtained from all chitin yielding invertebrate sources of India and a foreign exchange of 600 million US$ could be earned annually. Awareness has to be created among sea food processors to put up plants to convert shellfish wastes into chitosan. Similarly pharmaceutical industries may use chitosan in the development of new drugs. Types of training and awareness programmes to be organized for entrepreneurs, sea food processors and pharamacists are discussed in this paper.IntroductionIndia earns annually foreign exchange to the tune of 0.8 million US$ by exporting processed marine crustacean shellfish resources such as shrimps, crabs and lobsters (Figure 1) through 300 sea food processing industries. At present, only a small quantity of shell wastes (exoskeleton) generated from the above is utilized as an ingredient in fish feeds and hence much of the wastes are disposed off either as land fill or by direct dumping in sea. These wastes containing primarily chitin could be the major raw material for the production of a proteinaceous byproduct viz. chitosan, a highly valued pharmaceutically important source"

Jan 1, 2008

By D. D. L. Chung

"In-situ network composites are composites in which the filler network is formed during composite fabrication, in contrast to ex-situ networks which are formed prior to composite fabrication. A homogeneous in-situ network composite has the entire network at the same composition; a heterogeneous in-situ network composite has different parts of the network at different compositions. The homogeneous network composite is made either by the Method of Molten Filler Flow or the Method of Dissolution and Deposition; a heterogeneous network composite is made by the Method of Liquid-Phase Networking. Examples include polymermatrix and metal-matrix composites.IntroductionNetwork composites refer to composites containing a continuous three-dimensional network as the filler. These composites are attractive in their lack of delamination failure, which is usually characterised by two-dimensional composites. The filler and matrix in a network composite can be considered two interpenetrating networks. The mechanical interlocking of the networks adds to the cohesion of the composite. In cases where the filer is much better than the matrix in a certain property, the network nature of the filler makes the filler highly effective in improving that property in the composite in all directions. The property desired in the composite may be high strength, high modulus, low coefficient of thermal expansion, high thermal conductivity, or low electrical resistivity."

Jan 1, 1994

By H. Forrest

Lead smelting at Cookson Industrial Materials was formerly carried out using a combination of Blast and Reverberatory Furnaces. In the late 70' s these furnaces were replaced by two 20 tonne capacity Rotary Furnaces. This furnace type has proved to be more flexible in the range of feedstock that can be processed, including lead drosses, battery plate and even whole batteries. High rates of production have been achieved whilst attaining a good level of environmental control. The majority of the sulphur in the feedstock can be fixed by use of appropriate fluxes.

Jan 1, 1990

By R. F. Hammen

Copper is one of the most widely used metals in industrial processes and is also present in most mining operations. Extraction of copper from solutions often proves difficult due to the presence of complexing agents. ChromatoChem, Inc. has developed a Solid Phase Extraction (SPE) support (HiPAC) for removal and recovery of metals from wastewater. The HiPAC SPE support employs chelating agents covalently coupled to a long linker molecule. Several solutions containing copper and complexing agents were tested including 1) copper and carbonate, pH 9.8, 2) mixed metals and anions with copper and cyanide, pH 11, and 3) copper and the chelating agent EDTA, pH 11. The copper was extracted from solutions one and two at high pH, but the EDTA containing solution needed the pH lowered to make the copper available for capture. In each example, the copper concentration was significantly reduced by HiPAC SPE treatment.

Jan 1, 1994

By Zhi-gang Que, Sheng-li Wu, Guo-liang Zhang, Bo Su, Chao-gang Hou

NOx released during fuel combustion is one of the major air pollutants, such as acid rain and photochemical smog. At present, still not have an economical and effective method of inhibiting NOx emission for sintering flue gas. Therefore, controlling conditions of fuel combustions to enhance the reduction of NOx is important for decreased the emission. In this study, microsintering furnace has been performed to investigate the effects of NOx emission from char-N during coke breeze combustion. The results show that the emission concentration of NOx decreased with increasing temperature when it is sinter bed temperature higher than 1000℃. The lower emission concentration of NOx was obtained when the concentration of oxygen was decreased. And the maximum concentration of NOx will be reduced with the enhanced of heating rate. If heating preservation time was prolonged, it would promote to NOx reduction with reduction substances resulted in lower NOx emissions in the combustion of coke breezes.

Jan 1, 2015

By W. G. Davenport

Chapters 7,8and 9 calculated three combinations of: blast composition (mass% O2, mass% N2) oil quantity per tonne of concentrate blast temperature that will steadily produce molten 65% Cu matte from pure chalcopyrite-concentrate. The combinations are:

Jan 1, 2001

By R. D. MacDonald

The papers presented in this chapter cover a wide range of hydrometallurgical topics and might be considered to be unrelated to each other. All of the authors, however, utilized the basic methods of process mineralogy to characterize the reactants in their experiments and the products produced. The wide range of research topics which can be pursued successfully by the use of the methods of process mineralogy is a matter of interest in itself. One might speculate that the methods could be even more widely applied if only their utility were better recognized. These methods for characterizing reactants and products include principally x-ray diffraction, optical micros-copy, wet chemical analyses, instrumental chemical analyses, high intensity magnetic separation, micro-scale gravity separation, differential thermal analysis, micro-hardness testing, and judicious use of the sledgehammer and cold chisel. It is perhaps not by coincidence that most of the papers in this chapter were prepared not by mineralogists, but by hydrometallurgists, who are recognizing the importance of thinking in terms of mineral phases, and not just assays! It appears that the gap between process mineralogy and the mineral industry is closing, and that future AIME sessions promise to become established forums where mutual discussion of such topics as metallurgical "troubleshooting" and process design may become commonplace between plant engineer and process mineralogist.

Jan 1, 1981

By Manfred Schmidt

Realizing an invention of Professors Queneau and Schuhmann, Lurgi GmbH has developed a radically new lead smelting technology, which was demonstrated on a ?30,000 tpy scale at Berzelius Metallhiltten GmbH between 1981 and 1986. Designed to treat all grades? of lead concentrates as well as complex secondaries, the novel QSL-Process applied one bottom-blown, refractory-lined long reactor and comprises two basic steps: Continuous oxygen smelting of the green charge is followed by continuous carbothermic slag reduction. Four firm orders and a number of serious inquiries from major lead producers confirm that the QSL-technology has convinced the industry of inherent process advantages. These include low investment and operating costs, flexibility and environmental acceptance. In the fall of 1986 Cominco Ltd. decided to erect a 120,000 tpy QSL plant at the site of the Trail lead smelter. Feed materials will consist of lead concentrates and zinc leach residues. The designed QSL reactor has a total length of approx. 41 m, and working diameters of 3.74 m for the oxidation section and 3. 24 m for the reduction section .. Separate gas offtakes on both sections will enable to? reduce the sulfur dioxide gas volume, and to recover a mixed zinc-lead oxide fume. Operation of the QSL reactor will start end of September 1989. First results will be presented.

Jan 1, 1990

By Toshiyuki Nohira, Eiichi Takeuchi, Tetsuo Oishi, Hideki Ono, Hirokazu Konishi

Liquid metals were investigated as alloy diaphragms in molten salt electrolysis. Liquid metals have higher diffusion rates of elements than those of solid metals during electrolysis. Sn electrodes were used for the first step to study the electrochemical formation of Dy and Nd alloys in LiCl-KCl eutectic melts, demonstrating selective recovery of rare earth metals into liquid tin electrodes.

Mar 1, 2017

By June-Yong Eom, Jong-Jin Pak, Jung-Mock Jang, Min-Kyu Paek

The nitrogen solubility in liquid Mn-Si, Mn-Si-Fe, Mn-Si-C and Mn-Si-Fe-C alloys has been measured by the gas-liquid metal equilibration technique in the temperature range of 1673-1773 K. The additions of silicon, iron and carbon significantly decreased the nitrogen solubility in liquid manganese alloys. The experimental results were thermodynamically analyzed by the Wagner’s formalism to determine the first- and second-order interaction parameters of silicon, iron and carbon on nitrogen in liquid manganese. The thermodynamic parameters can be used to predict the nitrogen solubility in ferromanganese and silicomanganese alloy melts as functions of the melt composition and temperature at given nitrogen partial pressures.

Jan 1, 2014

By E. O. Stensholt

The Hybinette electrorefining process for production of cathode nickel was in use at Falconbridge Nikkelverk A/S, Norway, until 1975 when conversion to the new chlorine leach process was started. In 1978 the conversion to electrowinning had been completed, but further major improvements to the process have been made up to 1987. After a major expansion program in 1985 - 87 the refinery has a nickel capacity of 54 000 mt Ni/year. The main feed materials to the process are converter matte from the Falconbridge smelter in Sudbury, Ontario, Canada, and from the BCL smelter in Selebi-Phikwe, Botswana. A typical composition of the mixed feed to the refinery is: 40 - 45% Ni, 25 - 30% Cu, 20 - 22% S, 2 - 3% Fe and 1.0 - 1.5% Co. The matte is chlorine-leached in the first process step, nickel being dissolved selectively in a train of leach-cementation tanks. Essentially all copper and sulphur that was present in matte appears in the leach residue as CuS. In 1986 an autoclave treatment stage was added to the process to improve nickel extraction from the leach residue. The resulting strong nickel chloride solution is purified by the process steps (1) precipitation of iron and arsenic, (2) solvent extraction of cobalt and other minor elements and (3) precipitation of lead and the remaining impurities. The nickel solution is then fed to the tankhouse, where various nickel products are produced by electrowinning. The chlorine gas that is produced during the electrolysis is returned directly to the chlorine leaching tanks to dissolve more matte. After stripping from the loaded organic phase and solution purification cobalt is also produced by electrowinning. The copper sulphide leach residue, which contains some nickel, is dead- roasted in fluidized-bed roasters. The sulphur is recovered and sold as sulphuric acid. The calcine is leached in spent copper electrolyte, from which cathode copper is produced by electrowinning. Precious metals and the remaining base metals are recovered from the copper leach residue. The Falconbridge chlorine process is very versatile. It can accept a wide range of impurities in the feed and still produce metals of exceptional purity.

Jan 1, 1988

By Peter A. Spencer

The metallurgical parameters necessary for the design of a carmercial scale bio-oxidation plant have been determined for the treatment of a refractory arsenopyrite concentrate using a moderately thermophilic bacterial culture. The parameters considered were bio-oxidation rate, culture growth rate, nutrients, solids density, level of bio-oxidation, particle size distribution and oxygen uptake rate. The approach for obtaining the optimum values for these parameters is discussed and values based on results fran batch and continuous testing are given. Estimates of the capital and operating costs for a plant treating the carmercial arsenopyrite concentrate have been calculated fran the test data.

Jan 1, 1990

By Aly M. Abdel-Rehim

The present work deals with a study of the mechanical activation of processing of Egyptian monazite by its simultaneous ball-milling and pressure leaching in order to improve the recovery of thorium and lanthanides from monazite. Experiments of simultaneous ball-milling and alkaline leaching of monazite contrary to autoclave leaching were carried out in stainless steel ball-mills of cylindrical shape under different conditions of temperature, pressure, time and alkali amount and strength. The ball-mills were heated and mechanically rotated in an electric furnace by means of roll mechanism. The effective rotation speed was fixed at 130 rpm in all tests. The charge of steel balls of different diameters was equivalent to 45% of the total mill volume. Monazite was charged in ball-mill without preliminary grinding. It is found that high rate of monazite leaching by ball-milling leaching method is achieved at lower temperature, shorter time and lower expense of alkali than in autoclaves. The results obtained show that complete recovery of thorium and lanthanides from monazite (99.8%) by simultaneous ball milling and alkaline leaching is attained at 140°C within 2 h. It is concluded that processing of monazite by its simultaneous ball-milling and leaching is mechanically activated and accelerated as a result of grinding action of steel balls that caused the continuous removal of the hydroxide product from reacting particle surfaces. This leads to the exposing of fresh and activated monazite particles surfaces to alkali leach solution and consequently the acceleration of the reaction of monazite processing.

Jan 1, 2006

By Yusuke Kimura, Ken-ichi Yamaguchi

"Secondary materials have long been processed at the S-furnace of the Mitsubishi continuous copper smelting and converting process at Naoshima Smelter and Refinery. Intensive recycling in the recent years has formed concerns that impurities in the secondary materials may cause drastic changes in the chemical properties of the CL-slag, which is separated from matte in the smelting stage. Among various impurities included in secondary materials, the authors have studied the influences of sodium oxides in the CL-slag because the behavior of sodium oxide has scarcely been studied with respect to the copper smelting slag. The examinations have been applied experimentally on the distribution between slag and matte of arsenic whose acidic characteristics suggest strong affinity to sodium-oxide of basic characteristics in silicate melts. The results have been discussed by thermodynamic evaluations and the results of pyro-tests at the commercial furnace.IntroductionAt Naoshima Smelter and Refinery, the existing line of the Mitsubishi continuous copper smelting and converting process has been operated since 1991. The Mitsubishi Process consists of three furnaces namely the S-, CL- and C-furnace as shown in Figure 1. In the S-furnace, copper concentrate and powdery secondary materials (scraps, sludges, etc) are charged through the top lances with oxygen enriched air. The other secondary materials of lumpy shapes are charged through the chute installed on the furnace roof. Charged materials are smelted by the reaction heat in accordance with the oxidization of copper concentrate. The mixed melt of matte and slag overflows through the launder into the CL-furnace, where the melt is separated into slag and matte by the difference of their specific gravity. Matte is siphoned out and sent to the C-furnace and converted to blister copper continuously. The CL-slag overflows continuously through the slag outlet to be water-granulated. Granulated slag is sold as a raw material used for the cement production and so on. Various secondary materials have been processed at the S-furnace of Naoshima Smelter and Refinery. Intensive recycling in the recent years has formed concerns that the chemical properties of the CL-slag may change drastically due to impurities originating from secondary materials. Among various impurities included in secondary materials, the authors have studied the influence of sodium oxide in the CL-slag because the impact of sodium oxide has scarcely been studied with respect to the copper smelting slag. The examinations have been applied experimentally on the distribution between slag and matte of arsenic whose acidic characteristics suggest strong affinity to sodium-oxide of basic characteristics in silicate melts."

Jan 1, 2012

By Michael J. Mankosa

The increased emphasis placed on recycling of consumer and industrial waste products has generated a need for advanced separation techniques for recovery of valuable by-products. As a result, the metals recycling industry has made great strides in the recovery of used wire products through the application of chopping and screening processes. Unfortunately, in many instances, the final plastic reject still contains a substantial portion of valuable metal. Typically, this material has been discarded, since an appropriate separation technique has not been available. Recent work conducted by Carpco, Inc. in Jacksonville, Florida indicates that a high-grade metal and/or plastic product can be recovered from this waste material using a novel density separation process. Extensive test work has been conducted using this procedure to validate separation performance as well as equipment capacity. This paper will present the basic operating principle of the separator, as well as results from tests conducted using various feed materials.

Jan 1, 1995

By Pertti Pekkala

Outokumpu has 25 years of experience in the SX area. The development of the solvent extraction plants responds to an ever increasing demand for lower operational costs wd for adaptability to process disturbances with minimized risks. In this paper the features of the VSF ("Vertical Smooth Flow") SX technology are described, such as the separated pumping and mixing, the homogenous gentle mixing, the droplet coalescence and the ultra pure settling. A major advantage of the mixing technology is the high stage efficiency of above 99 per cent. The connection between this and some features of the settler front section is clarified. The present design of VSF plants is based on experience of existing operations at, for example, Zaldivar, Radomiro, Morenci, Kokkola and Harjavalta. These production plants cover a unit capacity range of 60 to 3,600 m3/h expressed as a total flow. It is evident that there are no restrictive factors to increase the total flow up to 5,000-6,000 m3/h by introducing the VSF technology. The copper SX technology has a long history reflecting many individual features of the separate copper SX plants. Still it is necessary to verify all actual running parameters by pilot tests taking into account impurities, chemicals used etc. The design of SX plants is not only about the delivery of equipment but also a process concept, and it is best tailor-made and adapted to specific local requirements.

Jan 1, 1999

By Fathi Habashi

In the past five years Cuba has been attempting to more than double its nickel production by constructing two new ammonia leaching plants. No metals are yet produced on commercial scale but a variety of oxides and sulfides. This report updates the Cuban nickel industry as a result of two visits : one at the invitation of the Cuban Ministry of Basic Industries in 1987 and the other as a consultant to the United Nations for the Cuban Laterite Project in 1989.

Jan 1, 1993

By Osarnu Inoue

In Mitsubishi Continuous Copper Smelting and Converting Process, smelting, slag-matte separation and matte converting are continuously carried out in series in three furnaces connected by launders. As a result of this operational configuration of the furnaces, influence of the change in operating condition in upper stream, such as variation of feeds in the smelting furnace, propagates to down stream with some delay. In order to achieve stabler operation, process control algorithm based on the dynamic characteristics of each furnace would be very effective. In this study, the dynamic process simulation model was developed for the smelting furnace. The model consists of two mathematical modules, i.e. the thermodynamic module and the mixing module. The calculation results using operating data obtained at Naoshima Smelter showed good agreement with the actually observed change in temperature, composition and flow rate of matte and slag at the outlet of the furnace. In addition, operation parameters such as reaction efficiency of oxygen and coal, dead volume of melts were estimated.

Jan 1, 1999

By D. W. Collins

Several organic and inorganic substances are widely used to control deposit structure and morphology during the electroprocessing of copper. Methods for monitoring the levels of thiourea, glue and guar gum during electrorefining and electrowinning have been successfully developed under the trade names of Reatrol and CollaMat. Other instrumental methods have been developed for additives and decomposition products associated with the electroplating of copper and other metals. Generally, these methods have been found to be either insufficiently sensitive or lacking in the desired selectivity for some or all of the additives. These procedures have mostly employed DC techniques; i.e., cyclic voltammetry, Tafel analysis, etc. In this work, chronopotentiometry (CP) and AC voltammetry were used to examine the interaction of glue, guar gum, thiourea and chloride during the electroplating of copper onto a platinum electrode. In addition, the interactions between the additives have been explored. It was found that glue in pure electrolyte (H2S04 and CuS04 only) had no effect on the chronopotentiogram. Glue was only active if chloride ions were present. The addition of thiourea resulted in several different chronopotentiograms depending on the presence of either chloride or chloride and glue. Thiourea used in conjunction with glue and chloride showed a significant increase in the polarization during copper deposition when compared to the electrolyte containing only glue and chloride. The use of a modified channel electrode further increased the sensitivity of CP. The use of AC voltammetry was explored as a technique to monitor some of the additives. AC voltammograms have more spectral detail then their DC counterparts and it is possible to monitor some of the additives at very low concentrations with AC techniques.

Jan 1, 1999

By Xiao Songwen

Based on the anion coordination polyhedron growth unit theory, the polymorph transformation mechanism of antimony white (Sb2O3) in hydro-process was investigated. The new findings had been verified in the commercial-scale test and it was shown that adding a small amount of tartrate ions was economical and effective for polymorph transformation of antimony white in hydro-process.

Jan 1, 2003