Search Documents

By Qiu Dingfan

The Slurry Electrowinning Process (SEP) is a new hydrometallurgical method and clean technology, Sulfide ores can be treated by the SEP without S02 emission and the sulfur from the sulfides can be recovered in element form which is easy to stockpile and can be transported at low cost. In a special slurry electrowinning cell one can achieve at the same time the leaching of elements from the feed and the electrowinning of metals from the electrolyte, Because the anode reactions are utilized for leaching of some elements the consumption of the energy is decreased, SEP also has the advantage of separation some elements, It is especially suitable for treatment of complex concentrates containing Pb, Cu, Au, Ag and S, which could hardly be accepted by any smelter. In this work, the behavior of different metals in this process has been studied and it was found that the separation of metals in some minerals is possible through the SEP, Beijing General Research Institute of Mining and Metallurgy (BGRIMM) has studied the possibility of the SEP to treat bismuth concentrates containing S, Be and F in laboratory and pilot-test scale as well as in commercial plants, The commercial plant was set up in 1997, It has been in operation since that time, According to the results of laboratory experiments and pilot- plant test, a new plant to treat complex gold minerals was set up in 1998 and is in operation in 1999

Jan 1, 2003

By Alva L. Kuestermeyer

This paper presents the results of an economic analysis in the production opportunities of various co-product and minor metals in the base metals smelting 'industry. Pro forma cash flow statements were prepared for each co-product and/or minor metal analyzed utilizing US tax laws for items such as depreciation and taxes. The generated cash flows are based on anticipated revenues, estimated capital and operating costs (where applicable), and nominal production data for the respective co-products and minor metals. The economic analysis includes consideration of items such as metal payfors and bonus metals ,payments per current smelting terms. Sensitivity analysis to market prices is also ,addressed.

Jan 1, 1995

By Michel G. Drouet

Dross, a major by-product of all processes involving molten aluminum, forms at the surface of the molten metal as the latter reacts with the furnace atmosphere. It generally represents 1 to 5 wt% of the melt, depending on the process, and contains on average about 50% free aluminum dispersed in an oxide layer. Since aluminum production is highly energy-intensive, dross recycling is very attractive from both the energy and the economic standpoints. The conventional recycling process using salt rotary furnaces is thermally inefficient and environmentally non-acceptable because of the production of salt slags. Hydro-Quebec has developed and patented a new salt-free technology using a rotary furnace heated by an electric arc between two graphite electrodes, called DROSCAR®. A 600-kW pilot plant in operation at LTEE is in use to demonstrate the process. This process provides aluminum recovery rates over 90%, using a highly energy efficient, environmentally sound production method. In 1994, 400 tonnes of aluminum dross were treated in this facility and several tests on various types of dross have also been conducted in early 1995. A report on the results will be presented.

Jan 1, 1995

By R. S. Tahautdinov, A. N. Posazhennikov, V. V. Bastrygin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Samples of iron ore and carbon reductant were chemically and physically analyzed. Green pellets were processed via a lab tube furnace to simulate RHF conditions. The nuggets and slag were chemically analyzed. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2011

By E. V. Redin

"The Bakal (South Ural, Russia) deposit of iron ore bearing iron carbonate (siderite) with the capacity of more than 1 billion tones belongs to the MMK. This ore cannot be fully processed via blast furnace technology because of high content of MgO. According to the investigations carried out in the USA and Japan in 1999-2004 the ITmk3 (Ironmaking Technology mark three) RHF technology is a breakthrough in Ironmaking. Four iron ore types (hematite, magnetite, high and low Al2O3/SiO2) were tested. Reduction, melting and slag removal can be achieved in just 10 min. The main objective of the investigation is to establish optimum operation conditions for the production of iron nuggets from iron carbonate bearing ore via the ITmk3 by means of the lab scale testing. Green pellets were processed via a lab tube (chamber) furnace to simulate RHF conditions. This preliminary test work provides valuable information which may be used for large-scale testing in a commercially sized RHF.IntroductionThe ITmk3 process upon which this paper focuses was developed by Kobe Steel in its research facilities in 1996 [1]. After pilot testing at Kobe Steel’s Kakogava Works in 1999-2004 the pilot demonstration plant was built and operations were successfully carried out by Mesabi Nugget joint venture in 2002-2004. Steel Dynamics has committed to building the commercial plant at the Mesabi Nugget site in Hoyt Lakes (Minnesota). Only 4 iron ore types (hematite, magnetite, high Al2O3/SiO2 and low Al2O3/SiO2), as well as 4 coal types with range of volatility, ash and fixed carbon were tested. Results were consistent with nugget characteristics confirming ITmk3’s flexibility with respect to raw material inputs. At the same time, no research in the field of nugget from iron carbonate bearing ore with high content of MgO has been done. Such kind of iron ore is restricted for charging into the blast furnace due to contamination of MgO. The reason for restriction is the limitation of load of MgO in the blast furnace. If a lot of MgO enters the blast furnace, slag becomes viscous. The viscous slag is obstacle for stable operation of the blast furnace."

Jan 1, 2012

By Laura Garcia H, Juan Carlos Gonzalez Islas, Luis Garcia Lechuga, Pedro Alberto Ramirez Ortega

"Electrochemical studies were performed to silver recovery from industrial wastes (radiographic films) on litanium flat electrode using a filter press-type electrochemical reactor with vertical orientation (known as REOV-01), as counter electrode was used a mesh-type DSA. Voltammetric studies were employed to fmd the current range under which silver reduction occurs. Using chronopotentiometric studies with controlled current, homogeneous deposits were obtained on the surface of the Ti electrode, to a current of -210 mA during 120 minutes to a constant linear flow velocity of 15 Lmin-1 was achieved 97% of silver recovery from industrial wastes. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy studies corroborated the presence of silver on Ti flat electrode. In addition, the silver concentration in the solution after the experiments was 1 ppm below environmental requirements. This indicates the viability of a filter press-type electrochemical reactor with vertical orientation (REOV-01) for silver recovery from radiographic filmsIntroductionIn recent years, the industrial sector has shown an increase in the use of silver due to new applications in different areas. In sectors such as photography, the consumption of silver has declined as a result of the boom in digital photography. However, the use of silver in radiographic applications has not shown greater variation (47.16 Moz), as the image quality is essential for diagnosis in various fields, such as medicine. All the silver used in photographic applications is discarded completely (solid or in effluent). At the present, several countries have been involved in silver recovering from industrial wastes due to the economic value and environmental impact they represent. The main source of silver recovery is the wastes generated by the photographic sector. Various technologies have attempted to recover silver contained in these wastes. However, they have not fully satisfied the requirements of maximum recovery, nor environmental level (less than 5 ppm) of silver in effluents [1,2]."

Jan 1, 2014

By Yasuo Kudo, Wu, Hayato Sato, Hiroshi Nakazawa, Shouming

"In order to recover copper from a waste nickel condenser powder, bioleaching experiments were carried out using Thiobacillus ferrooxidans in a shaking flask. The content of nickel and copper in the waste nickel condenser powder in this study were 8.0% and 3.5%. X ray analysis showed the peak of barium titanate. In the preliminary study using metal nickel and copper powders , the dissolutions of nickel and especially copper were accelerated with the addition of ferric iron in the bioleaching of nickel and copper powders while not in the absence of ferric iron. Ferric iron oxidizes both metals, and Thiobacillusferrooxidans oxidizes ferrous iron resulting from the oxidation of metals, whereby the dissolutions of metals proceeds. The dissolution rates of nickel and copper increased with increase in the concentration of ferric iron in the bioleaching of the waste nickel condenser powder.1. IntroductionNickel condensers rejected from manufacturing plants are crushed and landfilled. Waste nickel condensers contain nickel and copper and could be considered as nickel and copper ores. Since the capacity of landfills is diminishing, it is required to recycle metals of waste nickel condensers in order to reduce the amount of wastes landfilled. Conventionally, metals in the waste were recovered by dry metallurgy after the incineration.Nickel has been refined by solvent extraction - electrowinning method (SX-EW method). Recently the amount of copper refined by SX-EW method has increased (Takahashi, et al. 1994). This method is cleaner and consumes less energy than conventional methods. Nickel dissolved well in acid solutions, but copper is not. If copper is leached efficiently from a waste nickel condenser powder, SX-EW method will be applied to recover copper from them"

Jan 1, 2000

By J. M. Khodadadi

"A computational study of the effect of thermocapillary convection on melting of a droplet under the influence of an incident uniform heat flux is presented. The computations are based on an iterative, finite-volume numerical procedure using primitive dependent variables, whereby the time-dependent continuity, momentum and energy equations in the spherical coordinate system are solved. During the early periods of the melting process, conduction mode of heat transfer is dominant. As the thermocapillary convection is strengthened due to the growth of the melt zone, melting on the side of the droplet is observed to be much faster in comparison to the conduction-only case. Due to the skewedness of the temperature field, a new recirculating vortex is created which promotes melting within the droplet. The effects of the change in the sign of the surface-tension temperature coefficient on the melting pattern are also investigated.1. IntroductionMelting and solidification of materials are important processes which are encountered in nature and numerous industrial applications. Due to the recent upsurge of interest in such processes as spray casting, space radiators, rapid solidification, purification of materials, containerless processing, etc., there is a need to analyze the transport phenomena of melting and solidification in spherical configurations. Specifically, the effect of thermocapillary convection on the melting of metallic droplets has not been addressed at all. Only a few authors have studied the transport phenomena without phase change in spherical droplets. Oliver and DeWitt [l] worked out a series solution for the thermal and surface-tension-driven flow fields for a droplet experiencing an irradiant energy flux in the microgravity environment. Kudo et al. [2] solved the coupled momentum and energy equations numerically for the same problem without dropping the convective terms. Due to the nonexistence of any previous work on transport phenomena during the thermocapillary-assisted melting of metal droplets, this study was initiated to elucidate the features of the phenomenon."

Jan 1, 1999

By Billy W. Osborne

The use or primary dross as a source for aluminum ion in the manufacture of aluminum sulfate offers opportunities for an inexpensive raw material. The aluminum sulfate industry in the US is a mature market with numerous small plants operating close to major users. The majority of manufacturers use either bauxite or aluminum oxide trihydrate as a source for the alum¬inum ion.. However, using process technology developed and patented by IWC, the oxides are removed from primary dross for use in manufacturing aluminum sulfate prior to metal recovery. This process offers the benefit of reducing costs for metal recovery. This paper discusses some of the methodology used in this process.

Jan 1, 1995

By V. B. Telles, J. A. S. Tenorio, J. O. Alves, D. C. R. Espinosa

"The world production of crude steel in 2009 reached 1.2 billion tons. For each ton of steel produced, 150 kg of steelmaking slag and 20 kg of steelmaking dust are generated. These are wastes with considerable production and limited applications, therefore this work studied the recovery of these wastes into useful sub-products. The slag was used as raw material in the production of rock wool (a thermo-acoustic insulator) and the dust was inserted in the iron ore sintering process. Results showed that produced materials have exceptional proprieties, therefore the recovery of these wastes can contribute to decrease extraction of non-renewable resources, reduce the costs and impact of disposals, and aggregate value to the slag and dust.1. IntroductionSteel production using Eletric Arc Furnace (EAF) has grown over 119 million tones in the last years. In 2008 30.7% of all steel produced, was obtained through EAF. In United States of America (USA) the percentage of this process in the production of steel was about 58% in 2008, while in 2000 this percentage was only 47% [1]."

Jan 1, 2011

By Songlin Zhang

"The McCoy/Cove mine, located in Eureka-Battle Mountain trend of Nevada, is a gold and silver deposit. Case studies of recoverable reserve estimation for gold and silver were made using multiple indicator kriging and volume variance correction. The grade tonnage distributions of recoverable reserves were constructed and compared with the distributions defined by blast hole assays. Optimal pits were generated by Whittle 4D pit optimization package to analyze the impact of different processing recoveries at different economic cutoffs. The results were compared with ordinary kriging. The study indicates that the proposed method for multi-mineral recoverable reserve estimation is more accurate than kriging in tenns of grade and tonnage. The method of using recoverable reserves for pit optimization will maximize global reserve recovery and revenue, and is more efficient than condition simulation regarding computing power.ABSTRACT ONLY"

Jan 1, 1997

By Andressa A. Silva, Esperidiana A. B. Moura, Francisco R. Valenzuela-Diaz, Jorge N. Sales

This work aims to study the influence of the nanoclay Cloisite 20A incorporation on mechanical properties of ABS (acrylonitrile butadiene styrene). The incorporation of Cloisite 20A was made in two steps; firstly,a masterbatch was preparated and then, it was incorporated in ABS. The Cloisite 20A masterbatch using 40 % of nanoclay and 60 % of SAN (Styrene Acrylonitrile) was prepared in an adiabatic mill. After that, Cloisite 20A masterbarch at 1 and 5 % (wt) was added in ABS. The resulting nanocomposites were characterized by tensile tests and the correlation between properties was discussed.

Jan 1, 2015

By C. L. Kusik

Environmental issues are having a significant impact on how automobiles are designed and ultimately disposed of at the end of their lives. On one hand, increasing concerns about landfill disposal have resulted in greater attention being focused on recycling materials and components from old junk autos. On the other hand, corporate average fuel economy (CAFE) requirements have led to downsizing, use of coatings, materials substitution and other measures that often make recycling more difficult. Automobile makers have responded to Corporate Average Fuel Economy (CAFE) Standards in a variety of ways such as: Downsizing; Designing of more fuel efficient engines; Reducing aerodynamic drag by sleeker body designs; Redesigning by using thinner gauges of coated steels; and Substituting material such as lightweight plastic or aluminum parts for steel. Other driving forces affecting production techniques, choice of materials and recycling issues include the Clean Air Act and its amendments, RCRA. and other environmental legislation. The variety of materials used in automobiles makes the recycling issue extremely complex. Not only does one have different materials used in different automobiles for making similar parts, but changing designs, evolving environmental issues, landfill closures affecting solid waste disposal, and increasing raw material quality standards have created a complex set of dependencies related to materials use and recycling.

Jan 1, 1994

By Young-Chul Kang

The Onsan Copper Smelter of LG-Nikko Copper Inc. is a unique plant, which has been operating two smelting processes since 1998. The operation of the first one was started in 1979 with a capacity of 80,000tpy of copper in concentrates utilizing Outokumpu flash-smelting technology. The other one was started in 1998 based on Mitsubishi continuous process with a capacity of 160,000 tpy of copper in concentrates. Through several expansion projects, the total smelting capacity of both processes is expected to reach 430,00Otpy of copper in concentrates towards the end of 2002. This article describes operation advantages of having two different processes at one plant and comparative operation results in terms of productivity, impurity distribution, energy consumption and environment issues and etc.

Jan 1, 2003

By Yongzhong Xiao, Tiejun Chun, Jian Pan, Zhen He, Deqing Zhu

"In this paper, the reduction kinetics of low grade hematite ore was calculated. Mineralogy shows that the ROM (run of mine) ore is of low grade hematite ore type, assaying 27.2 wt% Fetotal and with main valuable minerals of hematite. The reduction kinetics shows that the reduction reaction rates of pellets with additive and without additive are all controlled by diffusion through the product layer. The calculated apparent activation energy of pellets with 12 wt% complex additive is 8.55 KJ/mol, dropping 62.23% compared to that of pellets without additive.IntroductionWith the rapid development of iron and steel industry in China, there has been a soaring demand for iron ores in the past decade. The imports of iron ores have increased from 148 million ton in 2003 to 620 million ton in 2010[1]. Therefore, large quantities of low grade iron resources are necessary to utilize in China at the moment. During the past years, extensive research has been carried out on the low grade hematite ores [2-6], such as reverse floatation, gravity separation, high-gradient magnetic separation and direct reduction-magnetic separation. Direct reduction-magnetic separation is an innovation way to treat the low grade hematite [7]. However, the research of reduction kinetics of low grade hematite is few. Some research about the reduction kinetics of reducing iron oxides by CO was studied [8]. The results indicated that the apparent activation energy is 8.0-28 KJ/mol when the reducing reaction is controlled by internal diffusion. The apparent activation energy is 50-75 KJ/mol when the reducing reaction is controlled by chemical reaction. In this paper, the reduction kinetics of pellets was also been studied."

Jan 1, 2012

By Xie Zhang, Jiang Diao, Xin Qiu, Lu Jiang, Bing Xie, Hong-Yi Li

"Duplex converter process, in which the first converter is used for removing phosphorus from hot metal (De-P), is an important way to produce low P-content and ultra-low P-content steels. In order to improve phosphorization removal and formation of slag with high basicity at relatively low temperature during dephosphorization converter process, effects of temperature, silicon content in hot metal and varied compositions of the De-P converter slag on phosphorus distribution between the slag and hot metal were investigated with thermodynamic calculations and by laboratory scale experiments in present work. Results showed that phosphorus distribution ratio between slag and metal was varied in 10.6~26.6 when basicity of the slag was in the range of 1.5~2.1 at 1370, and the distribution ratio was increased with increasing basicity and Fe10 content in the slag.IntroductionIt is known that phosphorus exists in steel in the form of solid solution, which can significantly improve strength and hardness of steel at room temperature. However, the plasticity and toughness of steel, especially the low temperature plasticity is sharply reduced and leads to high ductile-brittle transition temperature. This phenomenon is commonly known as cold brittleness of steel [1~3]. Hence, phosphorus should be removed as much as possible in the steelmaking process, because it is generally harmful to the iron and steel products."

Jan 1, 2013

By M. Ide, K. Takemura, S. Taenaka, K. Shinzawa

"The laser characteristic is strongry dependent upon the stoichometry of forsterite (Mg2Si04) and YSO (Y2Si05) single crystals, because of change in the valency and occupied sites of doped Cr in the lattice so that mole ratios of Mg0/Si02 and Y203/Si02 in the above single crystals must be precisely analyzed. In this study ICP-AES was applied for analyzing the mole ratios. Emission intensities corresponding to Si and Mg or Si and Y were measured at the same time with internal standard method. Preparation of sample solutions, measurement conditions of ICP-AES and interferences by coexisting components were discussed, resulting in excellently precise detennination of stoichometry of the above single crystals.IntroductionIn conventional stoichiometric analysis of single crystals, the stoichiometry is detennined by analyzing each component separately with titrimetry and gravimetry techniques. On the other hand, by stoichiometric analyses using ICP-AES, emission intensities corresponding to components are measured at the same time with internal standard method. Consequently erros caused by variation of analytical condition are canceled out.Cr-doped Mg2Si04 and Y2Si05 syngle crystals are known as laser materials. The change of valency and occupied sites of doped Cr affect the characteristic of single crystal as aleser materials. The change of state of doped Cr.Stoichometric composition of Mg2Si04 is constructed by 2mole of MgO and 1mole of Si02, and Y2Si05 is constructed by 1mole of Y203 and 1mole of Si02. In this study, required analytical precision in component mole ratio is within an error of 0.0010 for Mg2Si04 (CV=0.05wt%), and within an error of 0.0030 for Y2Si05 (CV=0.05wt%) (Table I )."

Jan 1, 1998

By Ruirui Wei, Yanhui Liu, Fangqing Yin, Meilong Hu

In China, Basic Oxygen Furnace (BOF) slag is traditionally used as an aggregate for civil engineering, for road engineering and fertilizer. In order to make full use of BOF slag, the experiments of BOF slag with high temperature roasting has been carried out and the phase transformation is studied. The BOF slag from Chongqing Iron & Steel is roasted in the electric muffle furnace at three different temperature. The influences of the high temperature roasting on change the phase composition of BOF slag was characterized by XRD. The results revealed that SFCA was produced at the high temperature in air atmosphere and melting temperature of slag was lowered. Therefore, if the BOF slag which treated by roasting was utilized in the sintering process, it is advantageous to improve the sintering strength and the formation of the liquid phase and reduce fuel consumption in the sintering production process.

Jan 1, 2015

By K. Asokan, K. Subramanian

"Electrowinning of copper by monopolar cells require common anode and cathode busbar and crossbars to connect each electrode to the respective common busbar. On the other hand, the bipolar configuration warrants the end electrodes only to be connected to busbars; there is substantial reduction in copper requirement. In the present work, an electrowinning cell with bipolar electrodes and end electrodes, each having an area of 1000 cm2 was designed and operated. The bipolar electrode is made of mixed metal oxide coated titanium mesh welded to plain titanium sheet. Coated titanium mesh acts as anode and the plain titanium sheet acts as cathode. Environmentally unacceptable lead anode and the recurring loss of lead are done away with. Closer spacing of the electrodes, paves way for the application of higher current density leading to mass transfer enhancement. Performance of bipolar copper electrowinning cell is reported.1. IntroductionThe normally adopted practice in electrowinning of copper is the conventional monopolar configuration. In this practice, the individual electrodes act either as anode or cathode. Hence there is a need to connect every one of the electrodes to the common anode or cathode busbar and crossbars running across the top of the cell are necessary. The common busbar carries very high current which is divided among the individual crossbars and hence has to be thicker in relation to the current load of the cell. The drawback of the need to use common busbars of thicker cross section and the need to have crossbars are obviated in the bipolar configuration."

Jan 1, 2009

By Jinfu Xu, Youqing Cao, Yuting Lv, Hang You, Peng Jiang

"In present work, we reported the fabrication of composites consisted of M42 powder metallurgy high speed steel and 45 steel at one step via spark plasma sintering (SPS) technology. The interface microstructure, compositions and microhardness with the interface forming mechanism were investigated. The results show that the morphology and microhardness within the M42/45 steel interfaces exhibit a gradient distribution. The interfaces possessed a transition layer up to 10.2 ?m with few distortions and microcracks. The formation of M42/45 steel interfaces were driven by both fusion and diffusion processes. The former one was primary at the early sintering process, while the later one becomes dominant over the followed sintering process.IntroductionPowder high-speed steels have been widely used in cutting tools, cold-hot tools and dies, as well as in cut materials and structure parts with wear resistance and high-temperature resistance, due to its high hardness, good wear resistance, desirable cutting toughness and favorable hot hardness [1-2]. For materials of some parts in practical production, not only the favorable toughness is required to resist the impact action, but also the high hardness and exceptional wear resistance are demanded. According to the functional requirements and working conditions, bimetal composite materials are prepared in a certain mode, proportion and distribution, by designing two metals with different chemical and physical properties [3-6]. Considering the composites exhibit different properties in different positions of the parts with a combination of the advantages of two metals, they can obtain enhanced properties that the single one can not achieve."

Jan 1, 2012