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By Shijie Wang

In pressure oxidation leaching of copper anode slimes, than 65% of the tellurium is m' cxtraoted during decopperizing. About l0- 15% of the selenium is also dissolved simultane¬ously by severe leach conditions. Current operation for the treatment of the leachate is to constantly recirculate the leach solution through a bed of copper turnings. The tellurium and sele¬nium are precipitated from the leach liquor as copper telluride and copper selenide and sepa¬rated from the solution by filtration. In order to improve the reaction efficiency and reduce the process cost, viz, minimize the copper addition, cut retention time, and reduce the energy consumption; a chemical reducing agent is studied and the cementation process tested in the laboratory. In this paper, the test results are presented and the process chemistry is discussed.

Jan 1, 2003

By Goran Vukovic

The use of gas purging plugs in the copper industry is a widely used practice. They provide substantial improvements especially in anode refining furnaces, where savings in process time and energy are obtained as well as refractory wear and buildups inside the furnace are minimized. The newly developed system, enables purging plugs to be implemented in both stationary and tilting furnaces, is in operation in vessels on three continents. An additional advantage in these furnaces above all other benefits is the significantly improved melting rate. This innovative and patented gas purging system consists of a purging plug cooling device and a slidable, cooled piping system. It provides compensation for any thermal expansion in the furnace lining and minimizes the risk of undesirable copper infiltration. User experiences and results of this widely used system are reported in this paper.

Jan 1, 2014

By QIE Jun-mao, DONG Fang, DENG Hao-hua

The DIL402C thermal dilatometer and STA449C thermal analyzer were employed to test the linear expansion and contraction coefficient，CP and DSC curve of 304 stainless steel. The result showed that the linear expansion coefficient range was 20.9700×10-6～21.5712×10-6 and the linear contraction coefficient range was 21.2528×10-6～21.9471×10-6.The linear expansion and contraction coefficient were higher than other steel grade，so the 304 stainless steel belonged to the crack sensitive steel. Because of the crystal phase transformation occurred during the 1000~1400 ℃,the curve of CP fluctuated obviously and the defects of casting blank occurred easily. Chosen 1414℃ as the liquidus temperature of 304 stainless steel based on the analysis results of DSC. The curve of DSC was unsmooth during 1450～1100℃，the crystal phase transformation occurs and thermal stability of slab was inferior.When the initial solidified shell formed in this temperature range,the thickness of the shell would be nonuniform and the surface defects occurred more easily.

Jan 1, 2015

By R. G. Reddy

Nickel solubilities in spent pickling solutions (i.e. HF-HNO3-H2O solutions ) were measured as a function of HF and HNO3 acid concentrations. The chemical analysis of the industrial pickling solutions and sludges were made. The stable phases observed in the sludges are FeF3?3H2O, and ( FeCr ) F3?3H2O. Pure Ni, and stainless steel type 316 were used in this study. The results showed that the solubility of Ni increased with increase in concentrations of HF in pickling solution at a fixed concentration of HNO3: An excellent agreement between the experimental solubility data and the theoretical data was obtained. X-ray diffraction analysis showed that the solid solubility product formed is mainly NiF2?4H2O compound.

Jan 1, 1992

By Fumitaka Tsukihashi

Increasing amounts of steel scrap are being used as resources for steelmaking. Therefore, there has been a growing interest in the removal of harmful tramp elements such as antimony, zinc, tin, arsenic, bismuth, lead and copper from the molten steel. The problem that should be solved is the economic removal treatment of residual tramp elements in the steelmaking processes and the production of high quality steel by reducing the effect of the contaminated tramp elements and satisfying the environmental regulations. In this paper, the available thermodynamic data of the residual tramp elements in the molten steel arc summarized and the possibility of the removal of residual tramp elements from the molten steel is thermodynamically estimated.

Jan 1, 2003

By M. Sakamoto, S. Karaswa, Y. Yoneoka, Y. Ohmizo

"The Annaka Refinery has been processing leach residue by Waelz process for 17 years. Recently, the quantity of the leach residue has increased due to a decline in the quality ~f zinc concentrate. Meanwhile, negative factors (e.g. deterioration of water balance due to improved electrolytic power consumption rate) have increased· in the processing of the leach residue.We have implemented various measures in responses to this situation, while striving to increase ·processing capacity and achieve stable operation. AS we have largely completed our assessment of the efficacy of these measures, we report on our recent process improvements.IntroductionWe have been treating leach residue by the Waelz kiln process since 1981. At that time, treatment of only 50,000 tons of leach residue per year was anticipated. However, subsequent process improvements have revised this figure up to 75,000 to 80,000 tons per year.However, today's increased Fe zinc concentrate grade has resulted in increased amounts of leach residue. In addition, improvements have reduced electrolytic power consumption rate of zinc electrolysis, limiting the amount of water that can be used in ·the zinc refining processes and for deaning leach residue. Consequently, we encounter an increasing number of problems and factors adversely affecting leach residue treatment, including increases in water-soluble Zn (WsZn) and. S (S04) in leach residue.To solve these problems, we have taken several measures to ensure long-term continuous operation and treatment of this increased · amount of leach residue. This paper discusses these measures."

Jan 1, 2000

By Robert E. Moore

Synthetic spinel is proving to be a highly effective refractory for specific applications, but its cost limits applications. Formation of spinel from a raw material such as diaspore or bauxite could provide a simple and less costly starting material. In the study reported here, finely ground (-325 mesh) diaspore from Missouri and bauxite from Guyana and China are combined with hard burned MgO (-325 mesh) in appropriate proportions to yield spinel and spinel with secondary phases. A classical sintering and dilatometer study was completed, followed by a microstructure study to determine completeness of the reactions and morphologies of the reaction products.

Jan 1, 1993

By Adolfo Pillihuaman Zambrano

Fe-Cr-C production is a very high electrical energy consuming process. Decrease up to 10% of this electrical energy is expected when self-reducing agglomerates are used. This research aims to understand how the synergetic effects are when stronger reductant, like Fe-Si, is substituted for coke in self reducing pellets. Brazilian chromites containing 41.2%Cr2O3 were mixed with petroleum coke and agglomerated with cement as the binder. Small amounts of 1%, 2% and 4% of Fe-75%Si were substituted for the equivalent petroleum coke, and pure silica plus hydrated lime were added for adjusting the slag composition. The mixture was pelletized, dried and submitted at 1773K up to complete the reactions. The results showed that the reduction reactions were 1.4 and 2 times faster with 1% and 2%Fe-Si addition, respectively, than with no addition. The microscopic analysis showed that it was formed a liquid phase, but the pellet did not collapse what indicates that the coalescence of the metallic phase depends on the dissolution of the pre-reduced particles of the chromites into slag.

Jan 1, 2008

By M. Hashimoto

The equilibrium distribution ratios of sulfur between molten copper and CaO-fluxes containing caF2 and caC12 were determined in the range of 1300° to 1400° C under carbon monoxide. The rate of approach to equilibrium is rapid and increases with increasing CaCll concentration. In CaO-CaFl-CaCl2 fluxes, the distribution ratio varies in a complex way with temperature and CaFl concentration. The results are compared with those obtained with the binary fluxes of CaO with BaFZ and MgFl ?

Jan 1, 1983

By David M. Davidson

Seven intrusive phases have been mapped to date in the 1 b.y. Red Bluff Granite Complex (RBGC) near El Paso, Texas. This batholith is 20 km2 in area and intrudes older supracrustal units as well as a trachyte ignimbrite cap. Two early microgranite sills are spatially separated 6 km from a porphyritic, three-phase "ring complex" by a tin-bearing, biotite granite which cores the RBGC. These units are intruded, in turn, by a riebeckite granite which locally exhibits lineated and pegmatitic textures as well as exceptionally high light REE and Zr values (800 ppm La; 3,000 ppm Zr). The riebeckite granite is exposed in three separate occurrences within the Franklin Mountains. REE values in the RBGC are depleted in HREE and show distinct negative Eu anomalies. Typical La/Yb ratios are 5:1-2:1 with Eu values ranging from 10-80 ppm. The mineral source of the high REE values in the riebeckite granite has not yet been specifically identified, but is believed to be zircon.

Jan 1, 1988

By Joseph Hamuyuni, Pekka Taskinen

We present experimental results for the liquidus in the system Cu2O - CaO -Al2O3 at 1250 oC. In this study, we quantified the liquidus by the equilibration/quench/analysis technique, with Cu2O, Al2O3, and CaO as primary materials exclusively. Experiments were conducted in air at an at oxygen pressure (p) = 21.3 kPa). Equilibrated specimens were quenched in brine solution of 10 wt% NaCl. We then quantified the liquid chemical compositions by means of Energy-Dispersive X-Ray Spectroscopy (EDS) and Electron probe micro-analyzer (EPMA). This study reveals inconsistences in liquidus surface of the present ternary diagram of the system here in mentioned. Differences of up to 10 wt % compositions of the species have been observed.

Jan 1, 2015

By M Kolbe

Co-Cu exhibits a metastable miscibility gap in the region of the undercooled melt. Specimens have been undercooled and solidified containerlessly into the metastable miscibility gap in an electromagnetic levitation facility (EML) and in drop tube (DT) experiments. Due to the high undercooling the velocity of the solidification front is very high and the microstructure is frozen in instantaneously. The microstructure of samples processed in the EML is influenced by the electromagnetic stirring due to the induction of electrical currents into the melt. A variety of microstructures has been observed. After undercooling below the binodal the liquid melt separates into the Co-rich L1-phase and the Cu-rich L2-phase. Two basic morphologies of the L1-phase can be observed, they can be attributed to the transition in dendrite growth from diffusionally and thermally controlled to only thermally controlled growth. Transient microstructures are observed after solidification in the vicinity of the binodal. Drop tube experiments, which lead to a rapid solidification of a distribution of droplets under reduced gravity conditions, in contrary allow for the observation of the early stages of demixing: the microstructure shows a homogeneous distribution of spherical particles of the minority phase in the droplets. The cooling rate of the droplets and its dependence on the droplet radius has been calculated. The solidification velocity as a function of undercooling has been measured in the EML for the composition Co-lB.Bat%Cu. The data are analysed in the framework of the LKTlBCT model with a velocity-dependent distribution coefficient as well as within a model of Galenko and Danilov using a kinetic growth coefficient of u=0.22 m/Ks.

Jan 1, 2002

By I. D. Reznik

Regularities of cobalt and nickel distribution between slag and matte, slag and metallic alloy on the base of concepts on exchange reaction equilibrium are considered. It is shown that the distribution of cobalt and nickel in industrial processes approaches to equilibrium one. Oxysulphiae influence on the bahaviour of cobalt, nickel and sulphur is shown. The recommendations on conduction of the processes of smelting, converting and slag cleaning based on the analysis of the methods or" non : ferrous metal separation from iron are given.

Jan 1, 1993

By S. L. Kher

The Singhbhum Copper Belt located in the state of Bihar in Eastern India bears evidence of ancient workings and indicates the existence of a civilized habitation in this region in the past. It was in 1833. how- ever, that the first official announcement of the occurrence of copper in the district was made. Although the occurrence was confirmed in 1847, it was not until 1857 that the first company was formed to exploit the deposits. This Company was dissolved in 1859 and from then until 1920, there were many unsuccessful attempts to develop and exploit the copper deposits in the Singhbhum area. In 1920. the Cordoba Copper Co. took an option on the Mosaboni area, which is nearly 10 km away from the present works located at Moubhandar, Ghatsila and exercising the option in 1924, purchased the mining rights from the Cape Copper Company. The Cordoba Copper Co. was then converted into Indian Copper Corporation Ltd. This was subsequently taken over by the Government of India in March 1972 and is now known as Indian Copper Complex (ICC), forming one of the two smelting units of Hindustan Copper Ltd.

Jan 1, 1976

By I. J. Moon

The reduction behavior of hematite by H2 and H2-CO gas mixtures was investigated to elucidate the reduction mechanism at 800-950 °C. The hematite compacts were made by Cold Isostatic Pressing to produce compacts of uniform shape and size. The compacts were sintered at 1000° C for 30min, and showed a contraction of 29%. Mercury pressure porosimeter was used for measuring the total porosity, pore size distribution and pore surface area of the compacts. Reduction was measured by means of weight-loss technique using Cahn Balance (Model : TG-171, capacity log, accuracy f 10pg). Microscopic examination and X-ray analysis were used to correlate the structure of reduced compacts with the mechanisms of reduction. Neither chemical reaction control nor diffusion control is adequate in describing the complete course of reduction of the hematite compact. The reduction of hematite compacts was initially controlled by the chemical reaction at oxidelmetal interface. The reaction goes through a transition phase .where it is undergoing a mixed control, followed by the diffusion control towards the end of the reduction. The values of apparent activation energies for chemical reaction control were 3.48-8.43 kcal/mol depending on the gas compositions.

Jan 1, 1997

By Chengxian Lui

Detailed mineralogical and metallurgical investigations were carried out on a phosphorous-bearing manganese carbonate ore from the Huayuan manganese mine, Hunan, China. Microprobe analyses indicate that the Manganese occurs mainly in calc-rhodochrosite and in rhodochrosite. The cOll'pOsitional range of these manganese carbonate minerals is 50 -80 % MnOJ3, 0 -35 % CaOJ3, 5-35 % MgC03 and 0 -15 F~. The manganese carbonate minerals are very fine grained, IOOSt are between 4.6 and 9.4 1m in diameter. The small grains are clustered into aggregates that form bands 0.5 to 10 rnn wide. The phosphorous-bearing mineral in the ore is fluorapatite and is in grains that are generally smaller than 6 1m in diameter. Metallurgical tests show that it is possible to concentrate the aggregates of manganese carbonate minerals by high intensity magnetic separation, and to reduce the phosphorous content by rpasting the concentrate to convert the manganese carl::x>nates to insoluble hausmannite, and then leaching the roast product with HCI to dissolve the fluorapatite.

Jan 1, 1989

By Ahmad-Bitar¸ Riyad N., Shadia J. Ikhmayies

"CdSi-xTex thin films with O<x<0.3 were prepared on glass substrates by the annealing of CdS:In thin films produced by the spray pyrolysis technique. The annealing was performed in nitrogen atmosphere at 400 --,C in the presence of Te vapor. The compositions of the films were determined by energy dispersive X-ray detection (EDAX) measurements. Scanning electron microscopy (SEM) was used to investigate the morphology of the films. The transmittance of the films was measured at room temperature in the wavelength range 400-1100 nm and used to produce the absorbance of the films. The first derivative of the absorbance was used to estimate the optical bandgap energy Eg by using the minima in the first derivative. The relation between the bandgap energy and the fraction x was found to fit with a parabola and bandgaps in the range 2.196: =Eg: =2.480 e V were obtained. Urbach tailing in the bandgap was also investigated.IntroductionPolycrystalline thin film CdS/CdTe solar cells are promising candidates for low cost and high efficiency photovoltaic applications. The fabrication process of these cells involves the deposition of a p-type CdTe absorber layer on top of an n-type CdS one which acts as a window. The efficiency of the solar cell is affected by the method of preparation of both layers [1, 2].Interdiffusion processes taking place at the CdS/CdTe interface have largely been realized to significantly affect the device performance [3] by changing the bandgap of both CdTe and CdS which modifies the spectral response of the solar cell [ 4]. The formation of a mixed crystal or a graded layer causes a reduction in the lattice mismatch at the CdS/CdTe junction [5] which is about 9% [ 6] and then a reduction in the number of interfacial states and recombination centers, thus enhancing the solar cell performance [7, 8]. A complete understanding of the properties of the intermixed layers CdSxTe1-x that usually constitutes the interfacial region in the CdS/CdTe solar cell is essential. According to our knowledge, a lot of research was devoted to the investigation of the diffusion of S into CdTe [3-5, 9]; but little on the direct investigation of the diffusion of Te into CdS [6]."

Jan 1, 2011

By Masao Suzuki

Over 5 million cars are scrapped yearly in Japan. After dismantling. scrapped automobiles, they are put into a shredder for differential recovery of ferrous and nonferrous metals. The residue, which is called shredder dust, runs over 1.2 million tons per year. This paper reports a entire sequence of scrapping. cars. in Japan with the following sections: (1) production and scrapped car management, (2) material composition, (3) dismantling, (4) shredder plant, (5) differential recovery of metals including specific gravity separation and newly developed color separation.

Jan 1, 1995

By N. Menad

. Electronic wastes are heterogeneous mixture, with mainly copper, aluminium and steel attached to or mixed with various types of plastics and ceramics. In general, small amounts of precious metals are incorporated in this mixture. Today, these components constitute an environmentally problematic fraction in disposal. Their physico-chemical characteristics have been investigated through chemical, x-ray diffraction, infrared spectroscopy, scanning electron microscopy and thermal analysis.

Jan 1, 2000

By Peng Jianping, Feng Naixiang, Di Yuezhong, Wang Yaowu, Pan Xijuan

A vacuum silicon thermal reduction lithium process is developed in present work which used lithium hydroxide, alumina and calcium oxide as raw materials. The process contains two steps, which are that Li5AlO4 clinker is prepared in ambient environment, and that metal lithium is extracted from Li5AlO4 clinker with ferro-silicon alloy as reductant in vacuum. On the basis of thermodynamic analysis and investigative experiments, feasibility of this process is proved. The results show that Li5AlO4 can be generated by calcination lithium hydroxide and alumina, the burning loss is above 31% under the conditions of calicination temperature above 750℃ and time more than 90min. The main phases of calcination product are Li5AlO4 and CaO. When the calcination product is reduced by ferro-silicon alloy in vacuum, the lithium reduction ratio can be over 80% under the conditions of reduction temperature 1200℃ and reduction time 60min.

Jan 1, 2014