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By Takaaki Shibata

The Tamano Refinery has developed two new processes for removing the impurities, arsenic, antimony, and bismuth from an electrolyte. The first process involves bleeding the surface electrolyte in the electro-refining cells. The copper concentration level in the outermost layer is lower than that in any of the other layers, while the impurity levels are almost the same in all layers. Bleeding the surface electrolyte increases the amount of impurities removed in the liberator by approximately 20%. The second process involves adsorbing antimony and bismuth from the electrolyte by means of chelating resin. As the electrolyte passes through the packed column of chelating resin, antimony and bismuth are selectively adsorbed. They are then desorbed by means of hydrochloric acid, and then recovered in the form of a highly concentrated antimony chloride solution by means of evaporation. This process almost doubles the capacity for removing antimony from an electrolyte.

Jan 1, 1987

By Hyun Kyu Shin, Byeong Deok Lee, Young Eun Lee

The reduction of Mn oxides at pre-smelting steps is an integral part of smelting processes for Mn alloys, and an understanding of its reaction mechanism is expected to contribute to the improvement of processing efficiency for Mn alloys smelting. The phase diagram shows that five Mn carbides are operative in the Mn-C system. Although they are expected to participate in the reduction of Mn oxides, no specific information is available yet to clarify their roles in presmelting carbothermic reaction of Mn oxides. Experiments with composite pellets prepared with Mn oxides and graphite powders show that Mn3O4 is reduced initially to MnO at about 1130oC and, subsequently, to Mn7C3 carbide as temperature increases further. At 1331oC, Mn7C3 carbide dissociates to Mn alloy and carbon. The degree of reducing reaction increases with increasing carbon balance in composite pellets and increasing temperatures.

Jan 1, 2014

By P. D. Lee

The effect of strontium on porosity formation in aluminum-silicon alloys is not well understood and there is no consensus upon the cause of the effects observed. This paper describes a series of experiments where the effect of adding strontium on pore formation was observed directly with combination of a traditional temperature gradient stage and real time micro-focus radiography. These in situ observations provide a new insight into the effect of strontium on the nucleation and growth kinetics of porosity. The addition of strontium was found to have a minor effect on the growth of the pores in the mushy zone. However, strontium appeared to alter the nucleation and stability of hydrogen bubbles within the melt. The interaction of strontium with titanium-boride grain refiners produced an even stronger change in the nucleation and stability of the bubbles formed.

Jan 1, 2002

By Józef Czemecki

Polish copper concentrates are characterized by high levels of impurities, particularly Pb and As. Two technologies are being used for copper concentrate smelting at KGHM Polska Meidz S.A., namely the shaft furnace process (Legnica Copper Smelter, Glogów I Copper Smelter) and a single-stage process for direct to blister concentrate smelting in a flash furnace (Glogów II Copper Smelter). Both technologies are used at different physical and chemical conditions which results, in different impurities behavior. The paper presents flow sheets for copper production in a plant using the shaft furnace process and in another in which a single stage flash process is used. The metals distribution in particular semi-products is given as well as a method for elimination of impurities from the copper production cycle. Methods are also discussed for alloy and matte converting and copper refining to obtain low Pb and As concentrations in anode copper (0.3% Pb and 1500 ppm As maximum) that are being used in the KGHM Polska Meidz plants. Useful co-operation between the plants using different technologies, aimed at the limiting the effect of undesired impurities on the quality of blister copper produced, is also described.

Jan 1, 1998

By Keiji Toyabe

Several purifying techniques have been developed for controlling the impurity levels in the copper electrolyte at Niihama Copper Refinery. These have been carried out as follows; i ) the study of the reaction in liberation made it possible to raise the current efficiency for arsenic removal by more than 50% and to decrease generation of arsine sharply. By applying this method, a good performance was attained at commercial operation. li) the antimony in the electrolyte can be successfully removed by contacting it with activated carbon. This procedure is applicable particularly when there is a large amount of antimony in the copper anode. lli) for the nickel sulphate recovery from the electrolyte, an electric evaporating system was developed. The characteristics of this process are, capability of continuous operation with less manpower, the high recovery ratio of nickel sulphate (more than 85% as nickel) and no black acid formation in the treated solution.

Jan 1, 1987

By Vladimir Mindin

Simulation of complex equilibria is usually done in the P-T-X coordinates, where "Xu is the amount of individual chemical components in the system. This approach is not productive in some very important cases: (i) investigation of "open" systems, (ii) determination of coordinates (trajectories) of mono-variant points, among others. To solve these and some other problems, we use the idea of chemical potentials of elements (CPE) of the system. A system of different coordinates axes (CPE-axes ) leads to a new strategy of simulation, observing the results of the simulation, and to efficient technology of compressing and storage the data of the simulation.

Jan 1, 1994

By Khalid Hattar, Alexander McGinnis, Buchheitm Thomas, Paul Kotula, Luke Brewer

"Understanding the effects of extensive radiation damage in structural metals provides necessary insight for predicting the performance of those metals considered for application in the extreme radiation environment. Predicting mechanical performance after long term radiation exposure is of great importance to extending the life of current nuclear reactors and for developing future materials for the next generation of reactors. A combination of finite element modeling, nanoindentation, and TEM characterization were used to rapidly determine the microstructure and mechanical properties influences of ion irradiation on a standard 3 l 6L stainless steel sample. The results of this study found that ion irradiation and small scale mechanical property testing can be used to characterize extensive levels of radiation damage structure, only when significant consideration is given to ion irradiation depth, surface roughness and polishing condition, the irradiation temperature, and many other experimental parameters.IntroductionFor either the success of next generation nuclear reactors or the extension of current nuclear reactors significantly beyond their designed lifetimes, research is needed into the degradation of the microstructure and mechanical properties governing the performance of the reactor alloys exposed to extreme environments. Although the exact dose and temperature of these nuclear reactor plans may vary, the cladding and other structural components will be exposed to greater dose and at elevated temperatures. To acco=odate these severe exposures, established cladding materials are being testing to longer exposure and new alloy compositions are being considered. [1-3] For neutron test facilities to reach 100 dpa level, exposure times often span several years, significantly limiting the down-select process of potential new materials for extreme radiation environments. Ion irradiation has been used as a technique to provide a look at the effect of irradiation damage on materials in a significantly shorter time frame. Previous work using proton irradiation provides a deep, broad, and relatively uniform defect profile compared to heavy ion irradiation; however, using this type of radiation still requires weeks to months to reach the 100 dpa level. [4] In this research, we investigated the feasibility of using heavy ion (nickel) irradiation and small scale mechanical testing to provide in a few days a first order screening technique for potential alloys that are being considered for advanced testing."

Jan 1, 2012

By Mariane Costalonga de Aguiar, Carlos Mauricio Fontes Vieira, Sergio Neves Monteiro

"This work evaluates the effect of incorporation of an ornamental rock waste into an industrial clayey body used for roofing tiles fabrication. Formulations with 0, 10, 20 and 30 wt.% of waste were prepared by replacing the sand in the industrial clayey body. The plasticity of the formulations was determined by the Atterberg limits. Specimens were fabricated by 18 MPa press-molding and then fired from 850, 950 and 1050°C. The specimens were tested to determine the water absorption, linear shrinkage and three points bending flexural strength. The results indicated that the waste improves the extrusion performance of the clayey body by decreasing its plasticity. The use of the waste was beneficial to the water absorption and mechanical strength of the fired clayey ceramic at 1050°C.IntroductionOrnamental rock is a natural resource available in the municipal area of Santo Antonio de Padua and located 150 km from the city of Campos dos Goytacazes, northe of state of Rio de Janeiro, Brazil. Intense industrial activity related to ornamental stones, especially gneisses, is traditionally occurring in the region. After mining, the flagstone is submitted to sawing to obtain blocks and then, after a manual operation, the final products are small flagstones [1,2]. During the sawing operation, a sludge composed of water and fine particles of rock is generated. A monthly production of 1000 tons of ornamental rock waste is estimated to be produced at Santo Antonio de Padua. The final disposal of this waste has brought serious environmental problems. Since most industries do not have an adequate sludge treatment, the waste is contaminating the soil and underground waters as well as obstructing rivers and lakes.Ceramic bodies industrially fabricated in the municipal area of Campos dos Goytacazes, 280 km from the city of Rio de Janeiro, are still empirically elaborated using a mixture of local clays. These clays are predominantly kaolinitic mineral, associated with high plasticity. Due to the excessive plasticity of the ceramic bodies, it is common to have dimensional defects in the final products after the drying and firing processes. Moreover, the kaolinitic structure and the presence of aluminum hydroxide confer a refractory behavior to the local clays. This impairs sintering during the firing operation. In the case of clay ceramics for civil construction, this results in greater porosity associated with elevated values of water absorption [3,4]. To avoid this problem, it is necessary to reformulate the ceramic body composition. The addition of both non-plastic materials to reduce plasticity and fluxes to condition the refractoriness is a possible alternative."

Jan 1, 2011

By Carlos Maurício Fontes Vieira, Sergio Neves Monteiro, Diogo Neves Henriques

"This work evaluates the effect of incorporation of an ornamental rock waste into an industrial clayey body used for roofing tiles fabrication. Formulations with 0, 10, 20 and 30 wt.% of waste were prepared by replacing the sand in the industrial clayey body. The plasticity of the formulations was determined by the Atterberg limits. Specimens were fabricated by 18 MPa press-molding and then fired from 850 to 1100oC. The specimens were tested to determine the water absorption, linear shrinkage and three points bending flexural strength. The results indicated that the waste improves the extrusion performance of the clayey body by decreasing its plasticity. The use of the waste was beneficial to the water absorption and mechanical strength of the fired clayey ceramic at temperatures above 1000 ° C.IntroductionOrnamental rock is a natural resource available in the municipal area of Santo Antônio de Pádua and located 150 km from the city of Campos dos Goytacazes, northe of state of Rio de Janeiro, Brazil. Intense industrial activity related to ornamental stones, especially gneisses, is traditionally occurring in the region. After mining, the flagstone is submitted to sawing to obtain blocks and then, after a manual operation, the final products are small flagstones [1,2]. During the sawing operation, a sludge composed of water and fine particles of rock is generated. A monthly production of 1000 tons of ornamental rock waste is estimated to be produced at Santo Antônio de Pádua. The final disposal of this waste has brought serious environmental problems. Since most industries do not have an adequate sludge treatment, the waste is contaminating the soil and underground waters as well as obstructing rivers and lakes.Ceramic bodies industrially fabricated in the municipal area of Campos dos Goytacazes, 280 km from the city of Rio de Janeiro, are still empirically elaborated using a mixture of local clays. These clays are predominantly kaolinitic mineral, associated with high plasticity. Due to the excessive plasticity of the ceramic bodies, it is common to have dimensional defects in the final products after the drying and firing processes. Moreover, the kaolinitic structure and the presence of aluminum hydroxide confer a refractory behavior to the local clays. This impairs sintering during the firing operation. In the case of clay ceramics for civil construction, this results in greater porosity associated with elevated values of water absorption and low mechanical strength [3,4]. To avoid these problems, it is necessary to reformulate the ceramic body composition. The addition of both non-plastic materials to reduce plasticity and fluxes to condition the refractoriness is a possible alternative."

Jan 1, 2008

By Tatsuo Itou

Both sales volume of Aluminum Can and its recycling rate are remarkably increasing here in Japan. In 1993, recycled can volume was 11.78 billion cans ( 116,258 metric tons ) and its recycling rate 57.8 percent. We, MITSUBISHI MATERIALS CORPORATION. the leading manufacturer of aluminum can in Japan and our affiliated companies are very deeply involved in recycling used beverage cans ( U.B.C ) and recycling them back to can stock. In this paper. I would like to present the following; 1. Recent trend of beverage can consumption in Japan. 2. Trend of aluminum can and its recycling rate in Japan. 3. Future of aluminum can business in Japan.

Jan 1, 1995

By L. Sh. Tsemekhman

A new technology for the treatment of copper nickel-containing concentrate after high-grade matte flotation to blister copper with the production of liquid silicate slags in a vertical autogenous unit with upper oxygen blow has been considered. The copper and nickel behavior in the process of sulphide copper concentrate interaction with silicate melt containing oxide copper has been studied. The general mechanisms of such interaction are found.

Jan 1, 2003

By Micheal McCarter, Biswadeep Saha, Meenakshisundaram Ramanathan, Chai Ren, Sivaraman Guruswamy

"Three-point bend test was used to study the effect of electrochemically charged hydrogen and magnetic field on the embrittlement behavior of AISI 4340 steel in this work. Acoustic emission signals were collected during the test and analyzed to gain an understanding of the crack growth process. Cathodic hydrogen charging in AISI 4340 steel resulted in drastic reduction of ductility and strength. Hydrogen embrittlement was characterized by a change in fracture surface from dimpled ductile surface to quasi cleavage type fracture. No significant effect was observed in the presence of magnetic field. The acoustic emission signals collected during the test provided an indication of the extent of energy released during the crack growth process.*Support of this work by NSF through the award DMR-0854166 is gratefully acknowledgedIntroductionGrowing interest in hydrogen as a clean fuel and use of steel and other iron based alloys for storage and transport of hydrogen has led to extensive study of the influence of hydrogen on the mechanical properties of these alloys. Hydrogen interaction with materials may result in degradation of mechanical properties. Embrittlement, either ductile or brittle, can be described as a condition which decreases the toughness of the material or increases the ease of crack growth. Hydrogen present even in few parts per million is sufficient to embrittle steels at room temperature [1]. In most cases, hydrogen exposure is through an electrochemical process in aqueous corroding environments. In such cases, they are prone to be exposed simultaneously to electrically induced magnetic fields, which are also believed to affect the hydrogen embrittlement susceptibility of these alloys. So it is also important to study the effect of magnetic field on the hydrogen embrittlement susceptibility. Hydrogen solubility by electrochemical process in aqueous solution is proportional to square root of current density for iron. [2,3]"

Jan 1, 2012

By J. R. Goode

There are at least a dozen methods of selectively removing cerium from a mixture of the rare earth elements (REE) including separation techniques based on the oxidation of cerium to the quadrivalent state. Several of the oxidation processes have been operated on a commercial scale, others have been tested and in some cases are part of proposed flowsheets. In this paper, we describe and compare the various methods. We also present preliminary estimates of the costs of early Ce removal and discuss recovery and purity aspects of the options.

By Jewel A. G. Gomes

Electrocoagulation (EC) has been performed with Al-Fe electrode system with changing polarity for the removal of arsenic from water. The removal process has been studied using ICP-AES and Anodic Stripping Voltammetry with a wide range of arsenic concentration (1-1000 ppm) at various pH (4-10) and residence times (1-60 min). Electrochemically generated by-products have been analyzed using XRD, FTIR, XPS, SEM/EDS and Mössbauer Spectroscopy. Results revealed expected crystalline iron oxides (magnetite (Fe3O4), lepidocrocite (FeO(OH)), iron oxide (FeO)) and aluminum oxides (bayerite (Al(OH)3), diaspore (AlO(OH)), mansfieldite (AlAsO4?2(H2O)), as well as some interaction between the phases. The amorphous or ultra-fine particular phase was also found in the floc. The substitution of Fe3+ ions by Al3+ ions in the solid surface has been observed, indicating an alternative removal mechanism of arsenic in these metal hydroxides and oxyhydroxides by providing larger surface area for arsenic adsorption via retarding the crystalline formation of iron oxides.

Jan 1, 2006

By Zhuoqing An, Qi Li, Zhancheng Guo, Yanling Zhang

Fluidized bed is an important iron-making reactor, especially for the finely sized iron-bearing materials. However, defluidization caused by sticking between particles extremely limited its wide spread commercialization. In this paper, apparent viscosity was put forward to express the ability of particles to resist movement, which is reasonably considered as the comprehensive results of interaction between particles. Meanwhile, an experimental measuring method of apparent viscosity of particles was proposed, during which the torque exerted on the rotating blade in a particle layer is measured, and then the apparent viscosity is obtained based on the motion equations of powder particles. Further, the apparent viscosity of iron particles was measured by using of this method, and the effects of shape, size, and temperature were examined. The data can provide important information for understanding when and why defluidization happened.

Jan 1, 2015

By Thais Cristina da Costa Caldas, Carlos Mauricio Fontes Vieira, Alline Sardinha Cordeiro Morais, Sergio Neves Monteiro

"This work has as its objective to evaluate the effect of the incorporation of a glass powder waste obtained from discarded and Hg-cleaned fluorescent lamp into clayey ceramics used to fabricate bricks and roofing tiles. Formulations were prepared with incorporation of the waste in amounts up to 10 wt.% into the clayey body. Rectangular specimens were prepared by uniaxial mold-press at 20 MPa to fire at 850 and 1050°C. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural rupture strength. The microstructure of the fired ceramics was evaluated by optical microscopy. The results showed that the waste incorporation significantly improved the evaluated properties mainly at 1050°C.IntroductionFluorescent lamps use mercury as a main component for its operation. This metal is potentially toxic and can contaminate soils, animals and water bodies. The problem is aggravated if considerations are made with respect to the amount of lamps that are commercialized and discharged in emergent countries like Brazil [ 1].By using appropriate recycling processes applied to discharging fluorescent lamps it is possible to reuse most constituents of these lamps into new productive processes. A study has shown that one million common fluorescent lamps can generate 900,000 tubes of clean glass [2]. Moreover, this Hg-cleaned gloss may be recycled in different products.In fact, to recovery and recycle all materials that constitute the lamp instead of discharging them. This action protects the soil avoiding the formation of environmental passives [3]. It is also relevant to mention that the glass from fluorescent lamps is 100% recyclable while its permanence in the environment would correspond to very long time pollution, since its decomposition time is undetermined [4]."

Jan 1, 2011

By Bingguo Liu, Daifu Huang, Jinhui Peng

"The conditions to prepare U3O8 by calcination from ammonium diuranate were optimized, and the response surface design method was applied to analyze the influence on the total uranium and U+4 of calcination temperature, calcination time and mass of sample. A quadratic equation model for the total uranium and U+4 of U3O8 was built and the effects of main factors and their corresponding relationships were obtained. The analysis of variance shows that calcination temperature and calcination time significantly affected the value of total uranium and U+4 of U3O8. The optimal calcination conditions were as follows: calcination temperature 931.83 K, calcination time 24.32 min and 43.89 g. Under these conditions the value of total uranium and U+4 of U3O8 was 84.78% and 28.02%, respectively. The validity of the model was confirmed experimentally and the results were satisfactory.IntroductionNuclear energy is clean, effective, and a sustainable from of energy. It plays an important role in overcoming the impending global energy crisis, and in reducing energy vulnerability. In addition, nuclear energy is a possible cheaper and cleaner source of energy compared to fossil fuels, with no not really, mining of uranium produces CO2 contribution to green house gases [1]. Uranium dioxide, one of the most important fuel pellets used as nuclear fuel in light water reactors, is manufactured by calcining ammonium diuranate to triuranium octaoxide, followed by its reduction to uranium dioxide using cracked ammonia at 700°C [2]. Earlier attempts to optimize the important calcination process through several common techniques have not yielded desirable results [3]. These techniques either rely on the classical one parameter at a time approach that ignores the combined interactions between physicochemical parameters, or are theoretical in nature. Furthermore, these techniques also require large number of experimental data to be generated [4]. In order to produce triuranium octaoxide in an optimized manner, which considers the interaction of different process parameters [5], there is a need to adopt a multivariate statistical technique."

Jan 1, 2011

By Dilek Kirgöz, Onuralp Yücel, Murat Alkan

"In this study, Mo containing Fe-based alloys, such as Fe-Ni-Cr-Mo, were synthesized using a mixture of Fe203-NiO-Cr203-Mo03 powders reducing with Al powders by metallothermic process which is a high energy efficient, fast and low-cost production technique for synthesis of cast alloys and advanced ceramics. Detailed thermochemical studies were simulated by using FactSage 6.2 Thermochemical software in order to calculate adiabatic temperature of the reactions and effects of initial molar composition on the final products. In the metallothermic processes, effects of stoichiometric Al addition and addition of the oxide powders (Alz03, Si02, CaO, MgO) on the metal recovery and compositions of final alloys were carried out. Final products were characterized by using chemical analysis (AAS), XRD, XRF and SEM/EDS techniques.IntroductionSelf Propagating High Temperature Synthesis (SHS) has significant advantages compared to the high technology furnace applications, such as very short processing time, simple operation, low energy requirement and low cost [l, 2]. In a SHS process, the ignition starts the combustion and propagates throughout the reactant mixture yielding the desired product. However, the disadvantages of the process such as inhomogeneous or unreacted products due to undesirable reaction rates needs to be overcome by changing some parameters such as ignition temperature, particle size, additive, atmosphere etc. [3, 4]. This work aims to establish a scientific and engineering background in the production of some cast Fe based alloys (Fe-Ni-Cr-Mo) which are used as surface coatings, wear-corrosion-oxidation resistive applications via SHS (Self Propagating High Temperature Synthesis) metallurgy which is attractive process technique regarding fast and low-cost production ability of cast alloys."

Jan 1, 2013

By Chengyi Ding, Xuewei Lv, Changyang Ji, Rende Zhang, Xiangwei Zheng

The fraction of liquid phase in sintered ore can be the most important factor to determine the sinter quality and yield in sintering process. The generation ability of liquid phase for mixture of iron ore powders is determined by basicity, roasting time, roasting temperature and chemical composition of iron ores. Five different iron ores were selected in this study and the dried powders of iron ore and CaO reagent (<200 mesh) were homogeneously mixed together at their required proportions, then 15g of the mixture was pressed under a pressure of 20MPa to make a cylindrical sample with a diameter of 20mm. The sintering temperature in this study was kept at 1280℃, the gas phase is air, the holding time was varied with its three levels of 5min,10min and 15min. After that, the sample was cooled under room temperature in the air, and the cooled sample was analyzed by using zeiss optical microscope. The mineral phase compositions were quantitatively determined with an open source image processing software, Image J whicn can calculate the fraction of liquid phase. Besides, the study on how to estimate the sintering behavior of the raw materials in different conditions by the theoretical calculation is of vital importance, and the development of this will greatly improve the sintering production. Factsage will be used to calculate the liquid phases formulation during the sintering. Comparing the experimental results and the theoretical calculation shows that the mass of liquid phase increases with increasing basicity during the sintering, besides, the mass of calcium ferrite increases with increasing basicity. The generation ability of liquid phase of iron ores can be predicted through the experiment verification.

Jan 1, 2015

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