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By Sne?ana Devi

Mineralogy is a significant scientific discipline, essential in establishing the nature and the character of raw materials, regardless of whether they are monomineral or polymineral. Mineralogical characterization is very important, because its results give valuable information on features and nature of examined materials. Information's on mineralogical nature of mineral raw materials influence directly the quality assessment of a raw material, and thus the possibility of its use. The possibility of use of mineralogy in different industrial branches confirms constant activity of this scientific discipline. By use of methods within mineralogical analysis (optical microscopy, x-ray diffraction and others) data on mineral raw materials can be obtained as support in mineral raw materials quality assessment. Short description of results of mineralogical analysis of some mineral materials (granodiorite, dolomites, clay, refractory materials, slags and casting powders) in this paper shows the importance of its support to quality assessment and determine the possibilities of their use.

Jan 1, 2009

By W. L. Dalmijn, J. M. Krowinkel

A recycling concept of end-of-life televisions starting with shredding will produce a complex material mixture, very heterogeneous in size, shape and degree of liberation. Basically all materials in television scrap are valuable, which means that recovery is important for either economic, environmental or sustainability reasons. However glass, plastics and metals are the materials with the highest potential for recovery. Non-magnetic materials from shredded television sets can be separated into three characteristic size fractions that need further separation for a high value-added recycling of the materials. This study investigated the potential of physical separation of these size fractions into valuable material streams using polyseparator, tlrldy current separator, dry and wet shaking tables and electrostatic separator. An overall mass balance of the mechanically processed televisions was calculated. Evaluation of the produced material fractions showed that heterogeneity in particle shape and size together with the presence of unliberated materials caused sever difficulties in separation when exclusively based on mechanical techniques. The results indicate that a certain degree of dismantling is necessary to achieve products of appropriate quality in physical separation. In order to improve recycling of electronic scrap through design for recycling cooperation between the electronics industry, the manufacturers and the recyclers of electronic goods is necessary.

Jan 1, 2000

By Milton Blander

"A review of concepts and theories for predicting thermodynamic solution properties of multicomponent high temperature liquid solutions is reviewed. During the last 50 years the ability to predict such properties for molten salts, silicates and metals based on the generally known properties of the lower order (often binary) systems has been developed and shown to provide predictions which are quite useful in science and technology. There are many gaps in our understanding of these high temperature solutions, especially for metals, and considerably more work is needed.INTRODUCTIONA number of solution theories and concepts have been developed which reliably predict the properties of multicomponent solutions from those of the lower order systems (often only the binaries). Because there is available data for a large fraction of the important binaries, the capability for making predictions for many multicomponent systems used in metallurgical separation processes is broad and potentially very useful. At the very least, the theories greatly minimize the data necessary for predicting properties of complex multicomponent solutions of molten salts, silicates and metals. It is the purpose of this paper to discuss the concepts which are demonstrably useful. We will discuss simple forms of the theories to make the concepts clear but we will refer to the publications which contain the more complex equations needed to treat the large majority of systems.A simple framework for understanding what we need to know in order to make technologically useful predictions is based on well known thermodynamic principles. In technologies and sciences where molten salts, slags magmas or molten metals are used or studied, one must often calculate the extent of a chemical reaction (or separation) or of phase changes. To do this, one must first write an equilibrium constant, K, for the reaction in terms of the standard free energy change of the reaction, ?G°."

Jan 1, 1996

By Qiang Zhong, Bin Xu, Qian Li, Yongbin Yang, Tao Jiang

Viscosity of slag determines the production efficiency, energy consumption and distribution of elements between metal and slag, which is very important for pyrometallurgy. Slag of goldantimony ore blast furnace smelting has seldom been studied. In this paper, the viscosities of gold-antimony ore smelting slags of different composition have been studied by the rotating cylinder method. The results showed that, for a slag of 38.95% SiO2, 16.17% CaO, 25.97% FeO, 10.25% Al2O3, 5.17% MgO, the viscosity can be decreased by reducing 3.24%-8.5% SiO2 or increasing 3.31%-9.56% CaO content. Complex SixOy z- from SiO2 acts as the main cause for the high viscosity in a slag of high SiO2. The increasing of CaO causes the decreasing of the amount of SixOy z- and the O2- dissociated from CaO breaks the complex SixOy z-, which can decrease the viscosity. Viscosity of different composition slag in the appropriate range temperature can be calculated from the Arrhenius equation.

Jan 1, 2015

By Milton Blander

A review of concepts and theories for predicting thermodynamic solution properties of multi- component high temperature liquid solutions is reviewed. During the last 50 years the ability to predict :such properties for molten salts, silicates and metals based on the generally known properties of the lower order (often binary) systems has been developed and shown to provide predictions which are quite useful in science and technology. There are many gaps in our understanding of these high temperature solutions, especially for metals, and considerably more work is needed.

Jan 1, 1996

By Jun Li, Lin Chen, Tian-zu Yang, Wei-feng Liu, Wan-da Bin

"The Chinese bismuth production accounts for more than 80% all over the world in 2011. The main raw materials of bismuth smelting are bismuth concentrate and by-products of Cu or Pb smelting process. Many traditional methods of bismuth smelting in china was reviewed in this paper, such as reverberating furnace smelting, blast furnace smelting, fire-refining, ferric chloride leaching-hydrolysis, slurry electrolysis, and so on. But all the traditional pyrometallurgy or hydrometallurgy process have such shortages of low recovery, poor environment, and high cost. Therefore new technologies are introduced into the smelting process of bismuth concentrate, such as low-temperature alkaline smelting and side-blown bath smelting with oxygen-enrichment. These technologies have got great progress on energy saving, emission reduction, and friendly environment. Finally the development direction of new technology on bismuth smelting was prospected.IntroductionAs a green metal, bismuth has a wider applications, just extending from the traditional medicine, metallurgical-chemical engineering, low-melting alloys, solders, catalyst, and electronics to cosmetics, flame retardant, storage battery, semiconductor, supper conductor and nuclear energy etc[1,2,3,4,5,6,7]. This will increase the production of bismuth and promote the development and progress of bismuth smelting technology. At present, The major bismuth-product countries are China, Mexico, Peru, KZ, Bolivia and Canada etc, and China are dominating. A survey from the USGS[8] showed that Chinese bismuth production were 12,500 tonnes and got 80% of the world's in 2011. Thus the technology of Chinese bismuth smelting have a great representativeness."

Jan 1, 2013

By Heinz Boeni, Daniel Ott, Uca Silva

"Latin America is facing a rapid increase in internet use. Penetration with electronic equipment is in some countries approaching the level of industrialized countries. There is an evident need to resolve the management of “end-of-life” computers and other electronic equipment. Several studies in Latin America assessed the increasing e-waste quantities and confirmed the importance of a sustainable e-waste management. This paper gives an overview on the status on e-waste management in Latin America, explains the challenges for establishing an e-waste management system in a developing country setting and highlights the social and economic potential and the possibilities of a regional approach.IntroductionGlobal ICT-Trade and generation of e-waste from ICTThe global production of electronic devices and particularly of Information and Communication Technologies (ICT) faces the biggest industrial expansion of the history: OECD figures show that global trade of ICT technologies has reached 7.7% of the gross world product by 2004, the major proportion accruing from China [1]. In 2006 an estimated 230 million computers and 1 billion cell phones have been sold worldwide which corresponds to a volume of 5’848’000 t [2]. As a consequence, Waste from Electrical and Electronic Equipment (WEEE), or e-waste, is by far the fastest growing waste component. It reaches more than 5% referred to Municipal Solid Waste and e-waste generation in developing countries according to UNEP is expected to triple by 2010 [2].According to the OECD e-waste is “any appliance using an electric power supply that has reached its end-of-life” [3]. The European WEEE directive [4] distinguishes 10 categories of ewaste: Big household appliances, Small Household Appliances, IT and Telecommunications Equipment, Consumer Equipment, Lighting Equipment, Electrical and Electronic Tools, Toys, Leisure and Sports Equipment, Medical devices, Monitoring and Control Instruments, and Automatic dispensers. In this paper e-waste and WEEE are used as synonyms. Focus will be laid on e-waste from IT equipment (IT-waste), corresponding to category 3 of the European WEEEDirective."

Jan 1, 2008

By N. J. Themelis

In the last two decades, the Outokumpu flash smelting process has become the dominant new technology for copper smelting and has? also been applied to the smelting of other metal sulfides. The application of oxygen enrichment and improvements in concentrate burner and furnace design have resulted in ever increasing smelting rates per unit volume of the reaction shaft. This paper examines the. rate phenomena taking place in the reaction shaft of the Outokumpu furnace and compares information obtained from a mathematical model of heat and mass transfer rates to results obtained in pi1ot tests conducted at Pori, Finland, and to actual performance of a number of flash smelters around the world. 2?

Jan 1, 1985

By Cesar Garban

The samples of the washings are characterized of the ore for physical, chemical and metalurgical properties for representivity. the optimum values are determined for the recuperation of gold of the washings of the gold ore from the zone El Callao, Venezuela by acidic solutions of thiourea of the following parameters: Ph , contact time, composition of the liquid mixture, ratio of solid to liquid, grade of liberation, in an apparatus designed for contacting solid powder of the mineral with liquid solution of thiourea mantained in suspension by bubles of compressed air. The experimental results showed that the velocity of lixivation in primier time of (20) minutes is rapid and practically 2/3 part of the reaction is completed. For experimental design of parameters, the optimum conditions of recuperation of gold determind in this experimental investigation are:

Jan 1, 1999

By S. N. Sinha

The distribution coefficients of lead and silver between copper and matte phases have been measured at two different temperatures. Experiments covered the ranges of 0.009-1.8, 0.07-0.13, and 0-11 wt pct lead, silver, and iron in matte, respectively. The distribution coefficients of lead have been measured at 1405 and 1505 K and correlated with lead and iron concentrations in metallic copper and matte. The values of the distribution coef¬ficient of lead between copper and iron-free matte, at infinite dilution of lead, have been determined to be 3.60 and 4,06 at 1505 and 1405 K, respectively. The distribution coefficient of silver between copper and iron-free matte is independent of silver concentrations and has been measured to be 2.13 and 2.21 at 1400 and 1500 K, respectively. For an iron-bearing matte, the distribution coefficient of silver has been correlated with iron concentration in the matte at both 1400 and 1500 K. From the measured values of distribution coefficients, the Raoultian activity coefficients of PbS and AgS0.5 in copper-saturated matte have been calculated. At infinite dilution, the following equations correlating the Raoultian activity coeffici¬ents of PbS and AgS0.5 with matte- composition and temperature have been obtained: log Y° PbS =1.515 + 1080/T 0.14 NFes lbS Fog YAgS = -0.074 - 425/T + 0.09 NFes. - 0.5

Jan 1, 1983

By W. K. Connor, O&apos

The Bureau of Mines has conducted beneficiation, carbothermic reduction, and leaching tests of Mn oxide ores as part of its evaluation of the Mn and Co resources of the West- Central Arkansas District. The major Mn oxides in the ore include cryptomelane, psilomelane, pyrolusite, and lithiophorite. Cobalt is contained within the Mn oxides. Nonbeneficiated ore was reduced at 800' C with coal and leached in ammonium sulfate and ammonium carbonate leach liquors. Ore concentrates were calcined at 600" C prior to reduction under the same conditions as the raw ore. Head analyses reported up to 21 ptt Mn and 0.11 pct Co. Extractions of 70 to 90 pct Mn and 40 to 60 pct Co were achieved.

Jan 1, 1992

By Qinmeng Wang

The oxygen bottom blown copper smelting process is a new technology which has been widely applied to the copper production in China. In this work, a computational thermodynamics model for this technology has been established, based on smelting mechanism and theory of Gibbs free energy minimization. The calculated results from the model agree well with the actual industrial data, indicating that the model can be used for the predictions under different operating conditions. The tendencies of the key parameters (such as Cu losses and Fe3O4 content in slag) and the distribution ratios of the minor elements (such as Pb, Zn, As, Sb and Bi) can be predicted by adjusting the oxygen/ore ratio charged into the bottom blown copper smelting furnace. The model can be used to monitor and optimize the industrial operations of the oxygen bottom blown copper smelting process.

By S. R. Hutchins

Several refractory sulfide and carbonaceous gold ores were examined to determine whether microbial pretreatment could be used to enhance gold recovery. Test samples were biologically leached using unique. thermophilic microorganisms to solubilize iron sulfide minerals. Gold recovery from sulfide ores and concentrates was enhanced following pretreatment with the thermophiles; responses varied widely for the individual materials. Although bioleaching had little effect on the preg-robbing characteristics of the carbonaceous gold ores, cyanidation of the bioleached residues yielded higher gold recoveries than cyanidation of the native ore. By combining bioleaching with abiotic processes designed to inhibit preg robbing, gold recoveries of 83-98% were obtained from carbonaceous ores yielding 10-50% gold recovery by direct cyanidation.

Jan 1, 1987

By Rak-Jun Choi

Plasma-induced damage of InGaN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) has been studied in terms of forward turn-on and reverse breakdown voltages, together with etch rate and surface morphology. The physical degradation of sidewall along with rough surface morphology of n-GaN caused by increased ion scattering induced the deterioration of the forward and reverse voltages. It was found that the turn-on voltage is sensitive to the surface roughness of the etched n-GaN and the breakdown voltage is strongly affected by the sidewall contamination. Annealing under nitrogen after the mesa etching improved the electrical properties of the InGaN/GaN MQW LEOs. Efficient blue light-emitting diodes (LEOs) were fabricated using InGaN/GaN triangular MQWs. The LEOs with triangular QWs showed a lower operation voltage and 2.4 times higher light output power than those with the rectangular MQW LEOs at 20 rnA and 20 "C. The intensity of electroluminescence (EL) at 20 mA was almost independent of ambient temperature in the triangular QW LEO, but decreased substantially in the rectangular one.

Jan 1, 2003

By Lv Guozhi, Niu Liping, Liu Yan, Zhang Zhiqi, He Jicheng, Zhang Ting’an, Dou Zhihe

"CuCr alloy can be extensively used as contact materials in integrated circuit, electrodes, electric contact and high strength conductor. We proposed thermit reduction-electroslag remelting method of preparing the large scale CuCr alloy. But there are pores and oxide inclusions in CuCr alloy prepared by thermit reduction process. This paper studied mainly the effects of ratio of reactant and additive on the inclusion type and their occurrences in CuCr alloy. The slags and CuCr alloy were characterized respectively by XRD and SEM. The results show that when the additive is Na3AlF6, the slag consist of Al2O3 and Cr. When the additive is CaF2, the slag consist of Al2O3, Cr, CaF2 and CaAl4O7. The inclusions in CuCr alloy are mainly Al2O3 and pores which disperse in Cu-rich zone and Cu-Cr phase interface. When 5% CaF2 and 5% KClO3 are added, there are fewer pores and inclusions, and the more better microstructure.1 IntroduceCuCr alloy is the contact terminal material with an eximious properties[1,2], which gradually replaces CuBi alloy becoming the first choice for contact terminal material in the medium and high power vacuum switch after the 1970s. The traditional preparation methods of CuCr alloy mainly contain powder metallurgy, infiltration process and vacuum electric arc melting methods. But the above methods exist some shortcomings, such as poor product quality, high cost of production, processes complex ect[3-9]. CuCr alloy is made by the thermit reduction self-propagating method, which uses CuO, Cr2O3 and Al as raw material to get the high-temperature melt, and then casts to manufacture CuCr alloy ingot, which response equation follows as:"

Jan 1, 2012

By Agnes Y. Lee

he U.S. Bureau of Mines developed a method to treat lead-contaminated soil and ebonite battery casing wastes to produce a nonhazardous material. The cleanup procedure involves wet screening to separate a minus 18-mesh soil fraction; removal of metal1ic lead, rocks, wood, etc. ; carbonation to change lead sulfate to acid-soluble lead carbonate; size reduction; acid leaching; and rinsing. The casing wastes undergo size reduction and washing to remove the lead sulfate sludge before carbonation. Similarly, the minus 18-mesh soil is carbonated, then acid leached and rinsed. In leaching, fluosilicic acid (H SiF,) and hydrogen peroxide (H20,) are used to dissolve lead compounds. An electrowinning method is employed to strip lead from the lead-rich leachate. The acid content in the leachate is replenished with fresh H,SiF, acid prior to recycling. Treated casing wastes and soils pass the Toxicity Characteristic Leaching Procedure (TCLP) test and can be reclassified as nonhazardous materia1s. Based on this process, a conceptual pilot plant has been designed which will be demonstrated on wastes from two Superfund sites.

Jan 1, 1993

By Ian Baker, Xavier Pierron

"Iron aluminides hold great promise for intermediate temperature applications (to ~ 600°C) because of their excellent oxidation and sulphidation resistance and good strength. However, they have poor low temperature ductility, a feature which is exacerbated by water-containing environments. This paper presents an overview of the effects of environment on the ductility of iron aluminides, including the effects of iron aluminum ratio; ternary alloying additions, particularly boron; strain rate; and temperature. The mechanisms involved in water-induced embrittlement are discussed.IntroductionOver the last few years, it has became increasingly evident that the ductility and fracture toughness of many intermetallic compounds, particularly aluminides, are reduced dramatically if they are mechanically tested in either air or in hydrogen-containing atmospheres (1-5). For FeAI and Fe3AI, it has been shown that water vapor, for example in air at room temperature, can form atomic hydrogen by reacting with the Al atoms (1, 2). As a result in iron aluminides, the environmental embrittlement process is quite similar to traditional hydrogen embrittlement. This can be easily demonstrated by either testing an iron aluminide in an environment free of the deleterious species or by testing at high strain rates, both of which result in greater ductility. The purpose of this paper is to review recent progress in understanding environmental embrittlement in FeAI and Fe3AI, and to consider possible environmental embrittlement mechanisms. Greater understanding of this phenomenon will lead ultimately to remedies to this problem which is a major reason for preventing the practical application of these materials. First, some background on the iron-rich aluminides."

Jan 1, 1996

By Shizhe Liu, Bing Li, Heng Wang, Zuxin Zhao

In this paper, cyclic voltammetry and chronoamperometry have been applied to investigate the effects of Nd2O3 concentration on the anode effects, critical potential for the anode effects and Nd2O3 reduction in LiF-NdF3-Nd2O3 melts at 950℃. The results show that the oxidation peaks in the potential of about 2.7V are attributed to the oxygen ions oxidation and the peak current density increases with Nd2O3 concentration increase from 0 to 0.5wt%. The critical potential caused the anode effects shifts to 0.3V more positive value as Nd2O3 content in the melts decreases from 0.01wt% to 0.5wt%. The cyclic votammograms on W electrodes in the LiF-NdF3-Nd2O3 melts present two pairs of reduction and oxidation peaks, indicating that the reduction of Nd ions in the LiF-NdF3-Nd2O3 melts in two steps rather than one step.

Jan 1, 2014

By Y. A. Chang, L. M. Pike, C. R. Kao

"Knowledge of the site preference of ternary solute additions is essential to developing an understanding of how these solutes affect the properties of B2 intermetallic compounds. A quasichemical model will be presented which is able to predict the site preferences of dilute solute additions to tliple defect B2 compounds. The only parameters required are enthalpies of formation at the stoichiometric composition. General equations are developed which can be used to determine site occupations and defect concentrations for dilute as well as non-dilute solute additions. These equations use atom pair bond enthalpies as the parameters. It is found that the site preferences of dilute additions are not always in agreement with predictions based on the solubility lobes in ternary Gibbs isothelms. Predictions for dilute additions to NiAl and FeAl are compared to expel1mental results found in the literature. Satisfactory correlation is found between the model and the experimental results. In addition, the predictions from the model on vacancy concentrations in Fe doped NiAl are compared to recent experimental results by the authors.1.0 IntroductionIntennetallic compounds with the B2 crystal structure such as NiAl and FeAl have been investigated recently for possible use as structural materials in high temperature, oxidizing, and/or corrosive environments. The major limiting property of these materials has been a lack of sufficient room temperature ductility. Attempts to improve the ductility have often been made through ternary or higher order alloying. For B2 compounds, substitutional alloying additions can occupy either of the two sublattices and this site occupancy can be crucial in determining how the alloying addition affects the properties of the alloy. In this manuscript we will discuss the use of thelmodynamic modeling to predict the site occupancies of ternary alloying additions in B2 compounds with the triple defect structure."

Jan 1, 1996

By Donald R. Fosnacht

An investigation was initiated to obtain the scope of the problems associated with recycling various waste oxide materials generated at Inland Steel and to identify and? test techniques that could possibly aid in increasing the amount of waste oxide materials recycled to primary. operations. Based on the results of this work, several new techniques were developed ?and tested on ?a plant or laboratory scale. These include the use of cold-bond agglomeration methods for producing waste oxide agglomerates for use as a cooling agent or scrap substitute in steelmaking operations, and the use of various techniques for beneficiating blast furnace flue dust and soaking pit rubble so that the upgraded materials can be utilized in sinter plant or ironmaking operations. The physical and chemical characteristics of the waste oxide materials and the results of the laboratory and plant testing are discussed in this paper.

Jan 1, 1985