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By Osamu Iida

In the Mitsubishi converting furnace (C-furnace), molten matte continuously undergoes intensive conversion into blister, and an excess amount of heat is generated, even after taking into account heat loss from the furnace, off-gas, and latent heat of melt. To absorb excess heat in C-furnace, recycled granulated converting slags (C-slag) were wastefully charged in the C-furnace. In contrast, supplementary coal is necessary to make up a shortage of reaction heat in Smelting furnace (S-furnace). To utilize the excess heat of the C-furnace effectively and accommodate the unbalance of heat utilization between S and C furnaces, three technological innovations had been carried out. ? Spent anode charging facilities in C-furnace was modified, in order to solve some spent anodes hitting and eroding the hearth bricks. ? Cubic pressed copper scrap charging facilities were installed in C-furnace. ? Facilities were newly installed in C-furnace to treat neutralized residue from the wastewater and dust treatment plants, previously treated in the smelting furnace. Above innovations led to the further effective utilization of heat, increase in production, and savings in energy costs.

Jan 1, 1999

By Raj P. Singh Gaur

Due to high concentration of NaOH in the digested slurry after scheelite digestion, it is diluted to about 4N before filtration to separate sodium tungstate solution from the sludge (residue). However, in practice there may be deviations in the normality of NaOH present in the slurry. There may also be variations in the temperature of the slurry and filtration time. Slight variations in these parameters could cause tungsten losses in the sludge via the back reaction: Ca(OH)2 + Na2WO4? CaWO4 + 2NaOH This paper pertains to the effect of normality, temperature and time on the tungsten losses in the sludge that is separated from ?diluted-scheelite-slurry-in-NaOH? via filtration. Results indicated that tungsten losses in the filtered residue (sludge) were quite significant when the slurry temperature was kept at 70°C or higher. The effect of high temperature was less significant at the slurry normality of 3.6 or higher. Combination of low slurry normality (<3.6) and high temperature (>60°C) resulted into large W-losses in the sludge.

Jan 1, 2006

By R. Chiarizia

Third phase formation, i.e., the splitting of the organic phase in two layers, is a common feature observed, under conditions of high loading, for many solvent extraction systems of both analytical and industrial interest. Although this phenomenon has been investigated in a large number of works, a structural and physico-chemical description is still lacking. In this work, small-angle neutron scattering (SANS) data for the tri-n-butylphosphate (TBP)-n-octane,Th(NO3)4-HNO3 solvent extraction system have been interpreted using the Baxter model for hard-spheres with surface adhesion. The increase in scattering intensity in the low Q range, observed when increasing amounts of HNO3 and/or Th(NO3)4 are introduced into the organic phase, has been interpreted as arising from interactions between small reverse micelles containing three TBP molecules plus solutes in their polar core. This intermicellar attraction, under appropriate conditions, leads to third phase formation.

Jan 1, 2003

By Atsushi Shibayama

The aim of this research was to develop a copper recovery process from mine tailings (0.34%Cu) using flotation followed by high-pressure oxidative leaching (HPOL) and solvent extraction. The results of HPOL using the concentrate of mine tailings obtained by flotation under the optimal conditions of the previous study shown that an efficient copper dissolution of 94.4% was achieved in an H2O media, while the copper concentration of PLS reached to be 2.9 g/L. The solvent extraction of PLS obtained from the optimal HPOL showed that 91.3% copper was recovered in stripped solution under the determined optimum conditions, in which the copper concentration achieved to be 44.8 g/L. Finally, a proposed copper recovery process from the concentrate of mine tailings was developed by combination of HPOL and solvent extraction, while a total copper recovery of 86% was achieved.

By Zhouhua Jinag

The attempt has been made to manufacture high nitrogen austenitic stainless steels by pressurized electro-slag remelting furnace with maximum nitrogen pressure of 7MPa. To obtain high nitrogen content in steels, the compound electrodes with different nitrogen sources (FeCrN, Si3N4) were prepared. Using the Si3N4 as the nitrogen alloying source, the silicon contents in ingots were prone to be out of the specification range, and the electric current fluctuated greatly and the surface qualities of the ingots were poor. The surface qualities of the ingots were improved using FeCrN as nitrogen alloying source. The sound and compact macrostructure ingot with the maximum nitrogen above 1.0wt% could be obtained. A series of high nitrogen austenitic stainless steels have been successfully developed by this method. The mechanical and pitting corrosion resistance properties of high nitrogen austenitic stainless steels were investigated. The results show that the steels exhibit excellent mechanical and pitting corrosion resistance properties.

Jan 1, 2009

By Aichun Dou

Au-Sb alloy sample in which the total amount of Cu and Ni is below 25% (wt. %). In practice, Cu and Ni were difficult to be dissolved in sulphuric acid solution by oxidative leaching under the atmospheric pressure conditions, because of the lower concentration of Cu and Ni in the sample. In this paper, pressure oxidation leaching in sulphuric acid system (POLS) followed by hydrochloric acid leaching (HAL) was employed to remove impurities in the Au-Sb alloy. The effects of variables in POLS on leaching ratios of different metals were investigated in detail. Under the optimal conditions: the concentration of H2SO4 is 1.5 mol/L, liquid-solid ratio is 7:1, the amount of oxidizer is 1.2 times of the theoretical amount, leaching time is 4h and leaching temperature is 427K, the leaching ratios of copper and nickel reached up to 99%, antimony, lead and silver were not dissolved in dilute sulphuric acid solution. The residue from POLS was then treated with hydrochloric acid solution in fixed conditions, the leaching ratio of antimony reached over 92%, the grade of gold in the ultima residue was enriched up to 66%.

Jan 1, 2016

By Xiao Caimei

The method of Substance Flow Analysis (SFA) provides a helpful tool for the study of the industrial metabolism of a certain metal within a regional level, such as copper, lead etc. In this paper the flows and inventory of cobalt in China, 2008, were traced with the STAF model, and the situations of production, fabrication and manufacturing, use and waste management in China were introduced. The result revealed that the resource of cobalt in China was so poor that a large amount of cobalt material or cobalt products needed to be imported, and there was lack of recycling of cobalt resources.0

Jan 1, 2010

By C. M. F. Vieira

This work has as its objective to characterize ceramic bodies for vitrified tiles elaborated with the mixture of nepheline-syenite flux and kaolinitic clay. Formulations were prepared with 0, 30 and 50 wt.% of nepheline-syenite incorporated in a kaolinitic clay. To determine the physical and mechanical properties such as dry bulk density, linear shrinkage, water absorption and flexural rupture strength, specimens were prepared by 30 MPa uniaxial pressure-molding and then fired in a laboratory furnace at 1150oC. The microstructure of the fired ceramics was evaluated by scanning electron microscopy. The results indicated that the nepheline-syenite improved the evaluated properties of the clay and attended the specifications of vitrified ceramic tiles.

Jan 1, 2010

By Richard D. Hagni

Quantitative techniques have become increasingly important in recent years in the study of ore minerals. Precise measurement of indentation hardness and reflectance is the most important quantitative ore microscopic technique for mineral identification. Reflectance measurements of various wave lengths under monochromatic light provide the data necessary for the preparation of spectral reflectance curves and for the quantitative determination of an ore mineral&apos;s color. The procedures for the measurement of indentation hardness, reflectance, and color coordinates have recently been standardized and 204 items of quantitative data for ore minerals are now available in the first issue of the quantitative data file of the International Mineralogical Association&apos;s Commission on Ore Microscopy. A number of systems utilizing these quantitative data for systematic ore mineral identification have been published and others are in preparation. Rotation properties, although not included on the data cards, are useful in the identification of certain groups of minerals. Other aspects of quantitative ore microscopic techniques include the utilization of automatic image analysis for mineral percentage determinations and the use o~ various microbeam instruments for elemental analyses. These techniques provide a greatly improved basis for mineral identification in mineralogical and beneficiation studies.

Jan 1, 1981

By Jagdish C. Agarwal

Although copper ranks very low in the order of abundance of elements in the crust of the earth, it has been one of the first metals utilized by mar, at his emergence from the Stone Age, about 10,000 years ago. Use of copper for weapons, tools, utensils and ornaments dates back to the twilight of history, 6,000-5,000 B.C. Native copper outcrops and the malleability of the metal explain its very early use by the cave-dwellers. The working, melting and extraction of copper from its minerals are among the oldest metallurgical achievements of the human race. The oldest complete smelting installations for the extraction of copper from its minerals, dated about the fourth millenium B.C., were recently discovered in the Timna Valley, Wadi Arabah, Israel. (1) The history of the developments of the extractive metallurgy of copper has been adequately reviewed recently. (2,3) The center of copper production migrated from the Eastern Mediterranean to Northern Europe (Mansfeld, Germany, Swansea, Wales) towards the end of the Middle Ages (1500 A.D.). The production of the metal was boosted tremendously in North America since the end of the nineteenth century (Fig. 1).

Jan 1, 1976

By Tianjiao Luo

The electroless copper plating process for continuous carbon fiber using CuSO4?5H2O as the main salt and formaldehyde as reducing agent was experimentally studied, including the effects of pH values and concentration of chelating agents, stabilizing agents and reducing agent on the electroless plating process. The surface morphology and the composition of coating were investigated by means of Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS), and deposited the coating thickness was measured by way of dissolution. The results indicated that the pretreatment of carbon fiber before plating was so important. This pretreatment could prevent the formation of the black cores, furthermore, it could form many active absorption cores with Ag as the center on the carbon fiber surface. Used the optimized parameters in this process, which led to a stable solution for plating, a homogeneous copper coating was conducted with the carbon fiber plated with favorable mechanical performance and high adhesion strength.

Jan 1, 2006

By David G. Dixon

A general, unsteady-state model for leaching of one or more solid reactant species from a non- reactive, porous, spherical pellet is derived in dimensionless form for the interpretation of leaching data, and for use in the design of coarse-ore leaching processes. The effects of diffusion rate, chemical reaction rate, variable reaction order, and competition between multiple solid reactants are examined using the concept of the effectiveness factor. It is shown that the model is capable of simulating both "reaction-zone" and "heterogeneous" kinetics, depending on the choice of three dimensionless parameters. Results of batch leaching tests of artificial ore pellets are presented, and their relationship to the model is discussed.

Jan 1, 1993

By E. Açma

In this study, the production of Cu, Co, and magnetic iron oxide from the ancient copper, slags, located in Küre-Turkey, is investigated. In the process under development, fayalitic slags containing 1% Cu, 0.43% Co are reduced in a D.C. arc furnace with coke or graphite additions. A metallic alloy, consisting of 3.8% Cu, 3.3% Co, 2.1% S, and the rest being Ice, is produced by granulation of the liquid metal. About 85% recoveries of Cu and C:o are achieved by hot sulfuric acid leaching of these granules followed by H2S precipitation. The, production of magnetic iron oxide is possible from the discarded leach solution, loaded v:ith FeS04, by using a method with geothite precipitation, dehydration, controlled reduction, and re-oxidation steps. The magnetic oxides produced have 20 m2Jg surface area, 1:8.3 aspect ratio, and the coercivity of 330-380 Oersted.

Jan 1, 1993

By Yungang Li, Hui Li, Ramana G. Reddy, Jinglong Liang

High solid corrosion protective coatings were prepared by the dust of the converter with an average particle size of 59.33 μm. The effect of different amount of benzyl alcohol diluent on the performance of high solid anti-corrosion coatings was studied. With the increase of the amount of diluent, the viscosity of high solid anti-corrosion coatings reducing, the film apparent bubble content decreasing, and film resistant to salt water corrosion ability decreased, while acid corrosion capacity enhancement. When the dosage of diluents is 15%, the coating film is more resistant to acid corrosion.

Mar 1, 2017

By E. Fregeau-Wu

The major obstacle in recycling steelmaking slags to the blast furnace is their phosphorus content. Removal of the phosphorus, which is primarily associated with the silicate and phosphate phases, would allow for greater recycle of these slags for their iron, manganese, and lime contents. Calculations show that separation of the silicates from the oxide phases would remove nearly 90% of the phosphorus from the slag. The variable grain size of the as-received slag made liberation by fine grinding difficult. Therefore, slow-cooling experiments were undertaken to improve the grain size distribution. The grain size distributions were determined using in-situ image analysis. The samples were ground to their apparent liberation size and high gradient magnetic separation was used to separate the magnetic oxides from the nonmagnetic silicates and phosphates. Liberation analysis and modeling was performed on selected separation products for discussion of benefication characteristics.

Jan 1, 1995

By Leila Figueiredo de Miranda, Leonardo G. de Andrade e Silva, Anderson dos Santos Mesquita

ThisworkseekstounderstandifPETcompoundswithcarbonblackcan be uses to replace polypropylene and polystyrene for anti-static packaging mate- rials. PETcompoundswerefabricatedcontaining10.0;11.0;12.0and15.0weight % of carbon black with a particle size 325 mesh. We determined the thermome- chanical properties (Dynamic Mechanical Analysis—DMA, Tensile Properties, Fracture Toughness, and Hardness) and Electrical properties of the compounds. In conclusiontheresultsshowthecompoundbased onPETfilledwith 15.0% carbon black might be used in the handling, transportation and storage of electronic components because their mechanical properties, thermal and resistivity are satis- factory for this purpose. (cid:1) (cid:1)

Mar 1, 2018

By M. Potesser

One of the main targets in the automotive mass industry and supplying industry is the weight reduction of the vehicle for decrease of the fuel consumption. For that reason combinations of different kinds of materials and connections of, for example, steel and aluminium are developed or are already successfully field-tested. A determining factor concerning the quality assessment of the welded joint during hybrid welding is the characterization of the intermetallic Fe-Al layer regarding strength, hardness, morphology and mainly the different phases in which Fe occurs together with the Aluminum (FeAl, Fe2Al5, FeAl3.). A combination of conventional light microscopy, SEM - EDX - analysis, the usage of an atomic force microscope including a Nanoindenter and theoretical thermodynamic calculations turned out to be highly effective. Based on the attained results, the constitution of the intermetallic FeAl layer, influenced by silicon, manganese and zinc, can be predicted.

Jan 1, 2006

By Mehdi Asgharifar, Rouzbeh Sarrafi, Radovan Kovacevic

"The surface treatment of aluminum alloys using atmospheric-pressure of low intensity DC plasma arc discharge is investigated in terms of surface properties. With respect to the conventional surface treatment processes for aluminum alloys mostly based on chemical etching or sand blasting, this process is very environmentally friendly and cost-effective. The effect of two processing parameters, the current and the plasma torch scanning speed, on the surface morphology is studied by using a scanning electron microscope. The effects of cathode spots within the tested range of process parameters are determined, and the limiting factors of the process (such as surface cracking) are discussed. The topographical studies of the treated surfaces have suggested potential enhancement of surface properties for different applications, such as preparing surface for painting and adhesive bonding.IntroductionIn the last decade the aluminum alloys are finding broad applications in automotive industry. In order to successfully execute the joining process of aluminum alloys such as arc welding, laser welding, and adhesive bonding, there is a need to remove oxides for welding and texture the surface for bonding along the join line. A number of surface treatment techniques such as chemical etching, sand blasting, and plasma treatment have been used by industry. It is shown [1] that plasma surface treatment is characterized as environmentally friendly, lower cost, and easier to control process. Bogaerts et al. [1] mention that when an adequately high potential difference is applied between cathode and anode, electrons are accelerated toward anode by an electric field coming in collision with gas atoms. The gas breaks down into positive ions and electrons, giving rise to gas discharge. The DC electrical discharges used in industrial plasma sources can be related to their location on the voltage-current curve as shown in Figure 1.It is generally believed that dark discharges other than coronas, and arc or torch plasmas are not very good candidates for surface treatment because oflow or high power density and active species flux. However, the glow discharge plasma is used for plasma surface treatment applications because of its proper power density and active-species flux [2]. Our objective is to investigate the feasibility of using low intensity DC plasma arc discharge as a surface treatment method without damaging the cathodic non-thermionic workpiece."

Jan 1, 2011

By Yuanbo Zhang, Xiaoming Mao, Zhixiong You, Zhenyu Fan, Tao Jiang

"It is generally known that the formation of calcium ferrite is favorable during the iron ore sintering, which dominatingly contributes to the improvement of strength and reducibility of the finished sinters. In this study, effects of roasting temperature and 02 content of inlet gas on the sintering mineralization properties of typical iron ores, including hematite, limonite, specularite and magnetite, were investigated. The results showed the amount of calcium ferrite initially increased then decreased with the increase of the roasting temperature. The temperature of maximum calcium ferrite generation amount for different iron ores was determined as follows: hematite and limonite was 1275 °C, whereas specularite and magnetite was 1250 °C. Increasing 02 content of inlet gas was advantageous to the generation of calcium ferrite during the sintering. The sequence of 02 content affecting the mineralization properties of different iron ores was determined as follows: magnetite > hematite > specularite > limonite.IntroductionThe mineralization property of iron ore plays a significant role in the mineral composition and microstructure of finished sinters, which determine the quality and output of the sinters [1-2]. The mineralization process of sinters is composed of solid-phase reaction, formation of liquid-phase and crystallization. The formation and crystallization of liquid-phase is the foundation to the mineralization as the quality of the sinter is poor when concreted by solid-phase consolidation [3-4]. With respect to the iron ore sintering, liquid-phase regarded as bonding phase is generated between the iron ores and fluxes at high temperature [5]. Calcium ferrite is the most favorable liquid-phase among the bonding phases which dominatingly contributes to the improvement of strength and reducibility of the finished sinters [6-8]. Especially for high iron-low silicon sintering and high basicity sintering, making sure sufficient calcium ferrite quantity and reasonable distribution is crucial to the sinters [9-10]. Therefore, carrying out the researches on the high temperature reaction properties of iron ores is of great significance [11]."

Jan 1, 2013

By Qing-Yun Huang, Xiao-Yi Zeng, Bing Xie, Hong-Yi Li, Jia-Rong Yan

"In order to utilize vanadium resource in vanadium-titanium magnetite ore efficiently, vanadium distribution ratio between hot metal and slag should be improved during BF process, meanwhile the precipitating of Ti(C,N) in slag must be minimized. Effects of temperature, Ti02 content in the slag and basicity on vanadium distribution between slag and hot metal were investigated by experiment and thermodynamic calculation. The results indicated that high temperature, low Ti02 content and high binary basicity of slag were beneficial to increase the vanadium distribution ratio. The effects of temperature and Ti02 content in slag on vanadium distribution were stronger than that of slag basicity.IntroductionVanadium is an important element that is widely used in industrial fields. Most of vanadium resource is hosted in vanadium bearing titanomagnetite [l]. Vanadium bearing titanomagnetite is thus one of the domainate raw materials to produce the vanadium products. In other words, the comprehensive utilization of vanadium bearing titanomagnetite is beneficial for vanadium resource utilization. Vanadium bearing titanomagnetite sources are abundant in Pan Xi of China [4]."

Jan 1, 2013