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A study of iron-removal from copper leachate by limestone precipitation followed by direct eltctrowinning of copper has been conducted. The influence of the process parameters: amount of precipitant, contact time, temperature, agitation intensity, solution acidity, and initial iron concentration on iron-removal was investigated. The effects of electrowinning time, cell voltage, solution acidity and temperature on electrowinning of copper were also investigated. The leachate contained 1.20 g/l cu2+ and 7.41 g/l total iron at pH 2.27. After contacting with 14 g/l precipitant for 2 hours, 97.5 % of the iron was attenuated and 98.4 % of the copper was recovered. With the following electrowinning conditions: 3 lead anodes, 3 stainless steel cathodes, 2.5 V, 39.41 A/m2 and 10.7 g/l H2S04, copper recovery-was 98.4 %. Purity of copper powder produced was greater than 99.0 %.

Jan 1, 1999

By Shunichi Ajima

PT. Smelting Co. was established in February, 1996 to construct and operate the Gresik Smelter and Refinery. The construction work of first Copper Smelter and Refinery in Indonesia was completed in the end of August, 1998 and it was put into the integrated test operation in December, 1998. Gresik Smelter and Refinery is designed to produce 200,000 tpy of copper cathode from copper concentrate supplied from Grasberg Mine of PT. Freeport Indonesia Company in Irian Jaya, Indonesia. As by product 592,000 tpy of sulfuric acid, 382,000 tpy of slag, 31,000 tpy of gypsum and 480 tpy of slime will be produced in the full operation. Major processes applied at Gresik Smelter and Refinery are: Smelter: Mitsubishi Continuous Copper Smelting and Converting Process ( Mitsubishi Process ) Anode Casting: Continuous Casting of Copper Anodes with the Hazelett Twin Belt Caster Refinery: ISA Process Acid Plant: Lurgi Mitsubishi Double Contact Process

Jan 1, 1999

By C. Hecker, J. A. Garcia

To determine the kinetic reaction mechanism, electrochemical experimental techniques of stationary polarization, linear voltammetry and faradaic impedance were used. Gold electrodeposition experiments were realized using an electrolysis cell, provided· by a rotary disk of vitreous carbon and or' platinum counter electrode of platinum mesh and reference electrode. Using an automatic measurement system voltarnmograrns and Nyquist faradaic impedance spectra were obtained. In this paper, responses for different cases were analyzed through faradaic impedance criteria, considering several kinds of diagrams obtained. The importance diffusion influence of aurocyanide ions and adsorption as controlling steps previous charge transfer was verified. A model of proposed mechanism is discussed.

Jan 1, 1997

By Yasuo Ojima

The mainstream of copper smelting processes in the world today is a combination of Outokumpu type Flash smelting and PS (Pierse Smith) converting process. Presently it can be estimated that about 50% of the worldwide copper production is produced by the Flash smelting process and 80% by the PS converting process. PS converting process due to its operational flexibility and despite its batch character of operation has been widely used in many smelters for more than 100 years. However, an environmental issue has been pointed out related to this process because of the difficulty of handling the fugitive gases. Recently several copper smelters in the world have been newly construeted and others have executed major modification and modernization. The continuous converting process has been applied in many of them instead of PS converting process. This paper compares PS to the emerging continuous converting process and makes a prospect of the future of the copper converting process.

Jan 1, 2003

By Shengli Wu, Juan Zhu, Wei Huang, Xinliang Liu, Kaiping Du, Kaifa Zhang

Based on the furnace burden of high content of Al2O3, the process of softening and melting and the characteristic of primary slag were studied with the increase of MgO content in the sinter and adding some MgO into the pellet. The results showed that the content of MgO in the primary slag increased with the increase of MgO in the sinter and pellet. Meanwhile, the permeability of the furnace burden was improved because of low viscosity of high MgO primary slag. Compared with the increase of MgO content in the sinter, the increase of MgO content in the pellet can improved the softening and melting characteristic of the comprehensive furnace burden more effectively. More Mg-bearing pellet should be chosen in the comprehensive furnace burden for the purpose of improvement the fluidity of primary slag and the permeability of the furnace burden in the burden of high Al2O3 content.

Jan 1, 2015

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 Mao Chen, Baojun Zhao, Zhixiang Cui, Leonel Contreras, Chuanbing Wei

Bottom blown oxygen copper smelting process developed at Dongying Fangyuan Nonferrous Metals shows many advantages such as flexible feed requirement, high productivity, low energy consumption and high direct copper recovery. However, the weak acid generated during the process is not stable which influences the waste management and continuous operation. The amount of the weak acid is determined by SO3 formed in copper smelting process. SO3 can be formed inside copper smelting furnace and boiler at different conditions. Effects of temperature and oxygen partial pressure on the formation of SO3 during copper smelting process have been discussed thermodynamically. Understanding of the mechanisms for SO3 formation will enable the operation of bottom blown copper smelting furnace to be optimized and generation of the weak acid in the process can be managed. The fundamentals developed in this study can also be applied to other copper smelting processes.

Jan 1, 2016

By Shun Fujieda, Shigeru Suzuki, Kozo Shinoda, Tetsuo Fujita

"Dowa Metals & Mining Co. Ltd. has developed and plant-practiced a unique scorodite synthesis technology (DMSP®) for arsenic immobilization by oxidizing Fe(ll) ions in the presence of As(V) ions. Dowa has improved the DMSP® technology and has developed the process extensively for other applications. This paper focuses on the applicability of the DMSP® for various cases of copper smelting, and introduces other technologies for fixing arsenic and recycling gallium from GaAs, simultaneously processing (fixing) arsenic and thallium, and fixing and recovering arsenic from dilute arsenic solutions. The DMSP® was found to be applicable not only for various processes in nonferrous smelting, but also for other applications with a high potential for reducing environmental problems.IntroductionDowa Metals & Mining Co. Ltd. developed a method for synthesizing scorodite at ambient pressure [1], The scorodite is precipitated by oxidizing Fe(II) ion in a high-concentration As(V) solution. The scorodite produced in this way does not readily release arsenic because of its high crystallinity. Dowa built a demonstration plant for this technology at the Kosaka Smelter and established the production of scorodite at 30 t As/month by treating intermediate products from copper smelting as the starting material. The DMSP® was demonstrated to be favorably applicable to copper smelting [2]. We are engaged in further increasing the amount of arsenic fixation by the use of this process. Further improvements in productivity, cost reduction and applicability in various processes have been devised. Dowa has been endeavoring to resolve other problems as well as to improve productivity. We have gained extensive knowledge on arsenic treatment in our endeavors, enabling us to solve problems and improve productivity. This paper introduces the investigations and developments related to DMSP®."

Jan 1, 2012

By Kimio Itagaki

As a fundamental study for smelting the copper matte with high contents of arsenic and antimony in a strongly reducing condition, phase relations between the liquid matte and copper-rich alloy phases in the Cu-Fe-S-As or -Sb quaternary system and between the liquid matte and iron-rich alloy phases in the Cu-Fe-S-As or -Sb system saturated with carbon were determined at 1473 K by a quenching method. Activities of arsenic and antimony in these systems were also measured at 1473K by Knudsen cell-mass spectrometry. Furthermore, distribution ratios of silver, gold and platinum between the liquid matte and copper-rich or iron-rich alloy phases were determined in relation to the arsenic or antimony content in the systems. On the basis of these data, the elimination of arsenic and antimony from the matte to the iron-rich alloy (speiss) and the recovery of precious metals in reduction smelting of the copper matte were evaluated. It was suggested that the addition of pig iron to make a strongly reducing condition and form the iron-rich alloy, which is fluid at smelting temperatures, will be useful for fixing arsenic in the speiss.

Jan 1, 2006

By Ligang Zhang, Wen Chen, Xinghua Liu, Jialin Li, Xiaoyin Liu, Zhenhong Liao

A research-scale fluidization and magnetization roasting device was developed to evaluate a processing option that might offset the complexity and high cost of the conventional magnetization roasting process on siderite. In this study, the operating parameters of the fluidization and magnetization roasting device for siderite were evaluated through cold-flow tests and magnetization roasting tests. The reaction mechanism functions of the fluidized roasting process are revealed with kinetic studies.

Jan 1, 2015

By K. Fukushima, K. Baba, H. Kurokawa, M. Yamagiwa

"The Toyo smelter has expanded its anode production capacity from 126,500 to 239,000 t/year by introducing technical oxygen into blast air for flash and converter furnaces and improving smelting facilities. Significant efforts were made in the expansion not to increase the number of workers, which mean development of some automation systems for the copper converters and anode casting wheel. The efforts have resulted in the above-mentioned increase in productivity and a saving of production cost as well as a decrease in the number of workers for the anode casting operation.IntroductionThe Toyo smelter has been performing a highly stable and pollution free operation since its commencement in 1971 (1). Its distinctive features are the on-line control by process computer (2) and the high productivity without trouble. But owing to the so-called oil crisis in 1979, we were faced with a sharp increase in production cost. To decrease the production cost, some measures for saving of energy were planned and carried out, such as conversion from oil to coal in a flash furnace (3), the heat recovery from converter slag and the introduction of technical oxygen in blast air with the intention of energy saving as much as possible.The first increase in production capacity and some savings of production cost were attained in 1982 by the introduction of technical oxygen in blast air for the flash furnace without major modification of the furnace as shown in Table I. The capacity of an oxygen plant is 7,800 Nm3/H as 90% O2 . Part of oxygen from the plant is also supplied to tuyeres of copper converters through an oxygen holding tank with a volume of 830 m3 at 7 kg/cm2-G."

Jan 1, 1989

By V. Gel

An analysis of the operation of rotary tilting furnaces has indicated that they ensure better recoveries of metal when smelting lump scrap from aluminum slags, brass and bronze. On the other hand, processing of slags (concentrates obtained by mechanical upgrading) in pear-shaped furnaces results in much lower performance values as might be expected. At the Novgorod metallurgical plant a process for blister copper production in a rotary TROF converter (Outokumpu, Finland) has been introduced on a commercial basis. Smelting of brass and bronze scrap to produce blister copper is carried out using the technology developed in Russia and differing from the Outokumpu technology by the types of flux used and the blowing conditions in fuel burners and for melt oxidation, as well as by the design of gas removal system, the design of nozzles for melt blowing and the use of carbonaceous reductant (coal) for magnetite reduction in slags. Industrial-scale testing has demonstrated that by means of special techniques the 30-tonne converter productivity can be increased by 30% to 40% as compared with its rated productivity.

Jan 1, 2006

By W. G. Davenport

H20 is present in many flash furnace inputs. Examples are: (a) moisture in concentrate and flux (b) humidity in blast (c) moisture in hydrocarbon fuel, particularly coal, Appendix IV. H20 may also leak into the furnace from damaged water-cooling jackets. H2O, especially that it be included H2O, exerts a strong cooling effect on the flash furnace. It is important our calculations. As will be seen from the calculations, gaseous and liquid H2O both increase flash furnace industrial oxygen and oil requirements. This is because gaseous H2O (humidity in blast) must be heated from its input temperature to the flash furnace off gas temperature. Liquid H2O must be evaporated and heated.

Jan 1, 2001

By Antonio de Lucas, Juan Francisco Rodríguez, Ignacio Gracia, Mª Teresa García

"The amount of waste of Polystyrene (PS) foams is increasing in last years due to their use in insulation, protecting and, storing many different food products. Conventional methods of recycling such as crushing and shrinking by heated air or frictional heat have the disadvantages of molecular degradation, resulting in a reduction of the quality of the recycled polymer. Dissolution and shrinking with suitable solvents is one of the cheapest and more efficient ways of polystyrene recycling but in the process of the solvent recovery by distillation a certain degree of molecular degradation is produced. In this way, CO2 supercritical technology appears as an interesting alternative for the elimination of solvent. This work proposes a global process to polystyrene recycling in two steps: a polystyrene dissolution with a suitable “green” solvent followed by its elimination by supercritical tecnologhy. In order to develop a “green process” the constituents of essential oils, limonene, terpinene, cymene, and phellandrene, are selected as the most appropriated solvents. Introduction In the last years, disposal of the non-biodegradable plastic wastes has been recognized as a serious environmental problem. Recycling these wastes has great interest in order to prevent the environmental pollution and to preserve natural sources (1, 2, 3). Since the Polystyrene foams (PS) is one of the most used foam in isolation, protecting and food storage most of recycling work is concerned with this polyolefin (4). The two main alternatives for treating polymer wastes are energy recycling, where wastes are incinerated, and mechanical recycling (5). Environmental argumentations such as toxic emissions are building up a public resistance against incineration process (6). Mechanical recycling is a popular recovery path for manufacturers and is carried out on single-polymer waste streams. Any way, the market for recycled products can only be found if the quality is close to that of the original. Unfortunately the process of classification and further recovery of these wastes makes them often more expensive than virgin plastic (7, 8). Solvent extraction is one of the cheapest and more efficient ways for PS recycling. If it is done in house of waste producers the separation between plastics could be easy and effective and the transport costs would be eliminated."

Jan 1, 2008

By P. C. A. Maia, J Alexandre, F. A. J. Saboya, A. R. G. Azevedo, G. C. Xavier

"This work shows the characterization of clay and the granite waste by-product from the sawing process of the granitic blocks, used as raw material for brick ceramic. Besides, shows the degradation of the ceramic material obtained with different by-product contents in the waste after lab test degradation, is investigated. The clay is obtained from mine use areas of ceramic industry in Campos-RI and the waste is originating from of the area of Cachoeiro-ES, an important center of decorative stone in Brazil. The mixes were made by the addition of 0% up to 10% of the waste in the raw material. After drying and firing up to 900°C, obtained prismatic pieces were considered intact. Physico-mechanical properties were obtained from wet and drying tests in laboratory considering 50 and 150 cycles. The results showed that the use of powder byproduct has a considerably influence on the weathering and strength of the material.IntroductionThe ornamental rocks and coating defines the most promising areas of business in the mineral sector [l]. In this context, the Espirito Santo appears as the main Brazilian state in production and export of ornamental rocks, representing 47% of national production [2] which in tum is one of the economic sectors most representative of this State, due of its transport logistics and port vocation that facilitates the export of such products.It is estimated that the state of Espirito Santo there are approximately 1,200 companies dedicated to the activities of ornamental rock by providing 20,000 direct jobs [ 1]. These mobilize support activities, such as companies that provide machinery, equipment and supplies for industries, including service providers for maintenance.However, the production of rocks produces about 15,000 tons of granite waste/month [3] only in the municipality of Cachoeiro ltapemirim-ES. This is justified by the presence of more than 500 extraction industries, cutting and processing of stone, with about 900 looms, waste generators.According to [4], there is great potential for the use of granite waste in red ceramics introduced for the manufacture of bricks, blocks structural ceramics. and other ceramic products, especially when evaluated on exposure to weathering."

Jan 1, 2014

By Xi Dai

The LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode materials for Li-ion battery were synthesized with Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) as Fe sources by high temperature solid-state reaction method. The Fe1xNixC2O4?2H2O(x=0, 0.05, 0.10) materials were produced by liquid co-precipitation method and crystal structure and morphology of cathode materials were characterized by X-ray diffraction and scanning electron microscopy. The composition contents and charge-discharge performances were measured by chemistry analysis and charge-discharge apparatus. The XRD patterns showed that LiFe1-xNixPO4(x=0, 0.05, 0.10) cathode material samples were well-crystallized homogeneous olivine-type phase, with only tiny trivalent iron impurities according to chemistry analysis results. Charge-discharge test showed that cathode materials possessed excellent charge/discharge capacities, about 150mAh/g at 0.1C rate and more than 120mAh/g at 0.4C rate. The polarization of cathode in charge-discharge process can be restrained effectively, for the potential offset between oxidative peak and reductive peak of doped LiFePO4 material was only 0.079V, lower than pure LiFePO4 markedly.

Jan 1, 2006

By K. Koike, N. Masuko, Y. Takasaki

At the Zinc & Lead'95 symposium, one of the authors presented several modifications of Pb-Ag-Ca alloy anodes for the zinc electrowinning process, and also, the behavior of some organic additives in the electrolyte. In this study, the mechanical properties of the electrode materials composed by Pb-0.5 wt% Ag-(0~0.8) wt% Ca were studied by the tensile and Vickers hardness methods. Furthermore, experimental research on the influence of rolling and annealing treatments on the electrolytic behavior and mechanical properties of these alloys was carried out. The tensile strengths of the annealed Pb-0.5 wt% Ag-(0.1-0.8) wt% Ca alloys were the same or higher than those of the as-cast Pb-0.9 wt% Ag alloy. The anode potential using the as-cast Pb-0.5 wt% Ag-0.6 wt% Ca alloy decreased compared to the as-cast Pb-0.9 wt% Ag alloy. Moreover, the annealed Pb-0.5 wt% Ag - 0.6 wt% Ca anode after rolling showed a lower anode potential than the as-cast Pb-0.5 wt% Ag - 0.6 wt% Ca anode.

Jan 1, 2000

By Shabnam Sabah, Geoffrey Brooks

In oxygen steelmaking, splashing and droplet formation play a key role in the kinetics of the process. Though splashing has been studied by previous investigators, there is only limited understanding of how different cavity modes affect splashing. Therefore, a cold model study (at various lance heights and gas flow rates) has been carried out focusing on the issue of cavity modes and how it affects splashing phenomenon. Analysis using Fast Fourier Transform (FFT) was carried out on cavity oscillation that showed that frequency and amplitude of oscillation was highest in penetrating mode. Measurements of splashing over a range of conditions showed splashing greatly reduced when cavities went from splashing to penetrating mode. The results were validated and compared with plant data and previous model investigations.

Jan 1, 2014

By M. Hashiuchi

In 1972, the tankhouse of the Tamano Smelter adopted a high current density electrolysis operation applying the PRC (Periodic Reverse Current) method. In 1994, the phase four production expansion project, which incorporated significant re-structuring of the organization, was completed and we have achieved an annual production capacity of 191,000 tons. The target of this project, the production capacity, was increased by 1'8% and labor productivity by 25%. After the expansion, some improvements in the starting sheet section and the verticality of the electrodes were carried out, and the efficiency of the operation was greatly enhanced, including the improvement of the quality of the electrolytic copper.

Jan 1, 1999

By T. L. Baum

External oxidation during in-line heat treatment of TRIP steels can cause problems for the subsequent coating process. This research aims to elucidate the kinetic rates of internal oxidation, external oxidation and decarburization and their interdependence under different gas atmospheres and temperatures. A rolled steel sample chemistry of 0.14 wt.% C, 1.8 wt% Mn, 0.6 wt.% Si and 1 wt.% Al is used as a case study. Thermogravimetric techniques are used to examine the net mass change in a sample during heat treatment and the results show an initial mass decrease and later an increase for particular partial pressures of H2O. SEM-EDS, optical microscopy and glancing-angle x-ray are used to quantify the microstructure. The cross-section of the samples have 4 distinct zones: (i) an external scale, rich in fayalite, (ii) an internally oxidized region with Al, Si and Mn oxides in an Fe matrix, (iii) a decarburized steel region, characterized by large ferrite grains and low carbon content, and (iv) a relatively unaffected steel core with a structure similar to the starting material.

Jan 1, 2006