Search Documents

By Zhenyang Wang, Yiran LIU, Xiangdong Xing, Jianliang Zhang, Zhengjian Liu

Basic characteristics of marine placer were systematically studied by chemical analyze, scanning electron microscope and X-ray diffraction in this paper. It could be found that the marine placer mainly consists of titanomagnetite and titanohematite. A series of experiments were performed to investigate reduction-magnetic separation for Fe and Ti from the marine placer. Effects of reduction temperature, reduction time, carbon ratio, magnetic density, and grinding fineness on the reduction-magnetic separation process were investigated. And the optimal process parameters were obtained as follows: the reduction temperature 1300, the reduction time 30 min, the carbon ratio 1.1, the magnetic density 50mT, and the grinding fineness of 0.074μm 86.34%. Under such conditions, the metallization rate, iron grade of magnetic substance and iron recovery reached to 94.23%, 97.19% and 90.28% respectively, and the titanium grade in non-magnetic substance and recovery of was 57.94% and 87.22% respectively. The effective separation of iron and titanium could be achieved in reduction-magnetic separation process.

Jan 1, 2015

By Tracy T. Morris, Luis G. Navaro

"Anodic copper slimes produced during the electrolytic refining of copper are routinely batch leached to remove copper. At the Amarillo Copper Refinery, an atmospheric leaching process was converted to an autoclave pressure leaching system to improve the removal of copper, reduce the consumption of oxygen, improve leaching times and enhance tellurium recovery. The benefits of pressurized versus atmospheric leaching of slimes were soon realized by obtaining the desired level of decopperization in a shorter time and with lesser quantities of reagents. The autoclave was designed and constructed with a unique oxygen injection system that enables good control of the leaching process and with no plug-ups. Other features include a mass measuring system that balances the quantity of slimes to be leached to the desired final solution concentration based on initial feed concentrations. The end result was a more efficient and controllable leaching process for removing copper from anode slimes.IntroductionThe electrolytic refining of copper consists of an electrolytic cell filled with a sulfiiric acid based electrolyte and pairs of copper anodes and cathodes. When a current is applied, copper in the anode dissolves and is plated onto the cathode. Impurities within the anode that are more noble than copper do not dissolve and end up at the bottom of the cell and are referred to as slimes. Gold and silver are the main slimes constituents of interest because of their monetary value, but there typically are significant quantities of selenium, tellurium, lead, antimony, arsenic, bismuth, nickel, silica and tin. Copper is also present, usually as a metallic or as a reactant with tellurium, selenium, oxygen or sulfur and can range from 10 to 30% of the slimes fall."

Jan 1, 2012

By Jiechao Liu, Lijian Luo, Yubao Ma, Bo Zhang, Yanfeng Yang, Xin Hong, Luming Liu, Jienan Liu

Reduction kinetics of stainless steel slag in iron bath smelting reduction was studied at the temperature of 1500℃ ~ 1650℃. It was concluded that the reduction process consisted of two parts. That is to say smelting reduction was controlled by stainless steel slag melting initially and by interface reaction later. In order to increase smelting reaction rate, the melting point of slag should be decreased at the first stage and adjust the liquidity of slag at later stage. Smelting reaction rate will be accelerated by means of optimize the slag content. The optimal reduction result that all most all of the chromium in slag been recovered was obtained in temperature was 1500℃, basicity of slag was 1.0~1.2, the value of Al2O3+MgO was 25%.

Jan 1, 2015

By Heinz Böni, Christian Ludwig, Bernhard Steubing, Uca Silva

"Chile will soon have to find solutions for dealing with rapidly growing quantities of Waste Electrical and Electronic Equipment (WEEE) due to its strong economy and fast increase of internet and communications technology usage. To support this process, the state of the Chilean recycling infrastructure as well as government, industry and consumer efforts to deal with ewaste were analyzed. Current e-waste quantities were assessed and future flows were predicted using a material flow analysis model. In this model computer hardware was used as tracer equipment for WEEE. Best available numbers indicate that today’s formal recycling infrastructure receives less than 3% of the annual quantities of computer waste. This study represents the most comprehensive analysis regarding e-waste in Chile, identifying relevant streams of e-waste and providing a basis for authorities and producers of electronic goods in order to take the necessary actions to establish an adequate recycling system.IntroductionSince 1991, Chile has experienced a period of strong economic growth. It is amongst the countries with the fastest development in the sector of Information and Communication Technologies (ICT) in Latin America and the number of people with access to ICT has been growing rapidly. The high growth rates of the computer market over the last years are representative for the ICT sector with the consequence that the generated quantities of electronic waste are increasing rapidly [1, 2].Waste Electrical and Electronic Equipment (WEEE) or e-waste is “any appliance using an electric power supply that has reached its end-of-life” as defined by the OECD [3]. Even though the overall waste management in Chile has improved much over the last decade, the issue of ewaste was hardly addressed. Due to the value of the materials contained in computer waste - such as precious metals, basic metals as copper or plastics - it may be assumed that an important quantity is already being recovered. This usually takes place on the informal market under questionable conditions for human health and the environment [1, 2, 4]."

Jan 1, 2008

By Shuichiro Okada

Various efforts to reduce energy consumption and smelting cost are made at Tamano Smelter. Production of anode copper has been increased by about 30 % and energy requirement has been decreased about 50 % respectively. Challenges toward more higher goal are being continued. Details about the following are described in this paper. 1 Waste heat recovery Steam recovery at up-take of FSFE Heat recovery from waste gas of anode furnaces 2 Application of tonnage oxygen 3 Application of pulverized carbonaceous fuels to the flash smelting furnace with furnace electrodes ( FSFE ) 4 Application of computer control system to copper smelting 5 Improvement of the fugitive gas collecting system 6 Improvement of the mechanical tuyere puncher for the converter furnace

Jan 1, 1983

By Joo Hyun Park, Soo Sang Park

The distribution behavior of Pb between molten copper and FetO-SiO2 (-CaO, Al2O3) slags was investigated at 1473 K (1200 oC) and p(O2)=10-10 atm in view of the reaction mechanism of Pb dissolution into the slag. The distribution ratio of Pb (LPb) decreases with increasing CaO content (~6 mass pct) irrespective of Fe/SiO2 ratio (1.4~1.7). However, the addition of alumina into a slag with Fe/SiO2=1.5 linearly decreases the LPb, whereas a minimum value is observed at about 4 mass pct Al2O3 at Fe/SiO2=1.3. The log LPb continuously decreases with increasing Fe/SiO2 ratio, and the addition of Al2O3 (5 to 15 mass pct) into the silica-saturated iron silicate slag (Fe/SiO2 < 1.0) yields the highest Pb distribution ratio. The log LPb linearly decreases by increasing the log (Fe3+/Fe2+) value. The Pb distribution ratio increases and the excess free energy of PbO decreases with increasing Cu2O content in the slag. However, from the viewpoint of copper loss into the slag, the silica-saturated system containing small amounts of alumina is strongly recommended to stabilize PbO in the slag phase at a low Cu2O content.

Jan 1, 2014

By Kai Kang, Jun Bao, Shouping Liu, Xiao Sun

Powder characteristics have a significant influence on selective laser melting (SLM) process. In this research, particle size, surface contour and the microstructure of IN718 powder used in SLM were tested, and the physical and chemical changes during heating process of the powder were investigated as well. The shape characteristic and fluid properties of IN718 powder were defined and measured. It is shows that most particles of IN718 powder exhibited nearly spherical shapes, and the particle size is about 22.95μm. On this basis, IN718 sample was fabricated by SLM process using the powder and the microstructure of the fabricated sample was investigated. The results indicated that the sample has a dense microstructure, no macro-defects but a few micropores and porosity. Compared with the powder, there was no new phase formed in the sample and melting point of the sample was little less than that of the powder.

Jan 1, 2015

By Norihiro Murayarna

Hydrothermal synthesis of K type zeolite was carried out by using coal fly ash as a raw material and KOH as an alkali source. The change in various physical properties of the obtained zeolite, such as the kind of zeolite crystal, cation exchange capacity, surface structure of zeolite and particle size distribution were investigated through the overall reaction of zeolitization. The reaction mechanism of K type zeolite from coal fly ash was investigated from these results in this study

Jan 1, 2002

By Kenji Monden

A simple technique is presented to evaluate optical property of biomimetic microlens array (BMA) as an antireflective surface on a polydimethylsiloxane (PDMS) sheet. The integration of these structures is done by a thermoforming process. We have only UV-VIS spectrophotometer for optical evaluation apparatus. The transmittance of the sheet is measured with angled sample holder. The 50 deg. transmittance of 270nm pitch BMA on PDMS sheet increases from 87 to 92% after the moth-eye structure is introduced. The transmittance of 350nm pitch BMA on PDMS sheet increases from 87 to 96% after the moth-eye structure is introduced. The transmittance increases with increasing pitch of BMA. The results obtained using UV-VIS spectrophotometer with handmade sample holder.

Jan 1, 2015

By M. E. Coleman, G. Money

"Clyde Materials Handling is an established customer-driven solutions provider, which utilizes its knowledge, expertise and technologies to transform the production processes of its customers, who operate in the ferrous and non-ferrous metals industries.With over 30 years experience in the process improvement industry, Clyde Materials Handling has helped their global customer base transform the way in which they operate their processes, which has enabled them to generate sustainable economic benefit and maintain their positions as leaders in their respective markets.Clyde Materials Handling has supported operators within the metals market by developing and deploying pneumatic conveying and pneumatic injection technologies. These environmentally supportive and sustainable solutions have been used to transport raw materials within operating facilities, from storage to silo, as well as injecting these materials directly into the heart of production processes.Clyde Materials Handling has worked closely with their customers, such as Codelco in Chile, where their pneumatic solutions have been used to inject a consistent, pulseless and accurate flow of copper concentrate into a bath smelter, which has helped to fuel the operational capacity, availability and productivity.This paper will discuss and highlight the ways in which pneumatic injection technologies, created by Clyde Materials Handling, and applied in partnership with their customers, have helped to improve the operational performance of the production processes of operators across the non-ferrous metals markets with specific reference to applications in the Peirce Smith Converter.Clyde Materials Handling has applications injecting Electronic Scraps, Dusts, Reverts, and other additives to the Peirce Smith Converter. They also have experience of modified PS Units used for Slag Cleaning. There experience with the Codelco Teniente Converter is also directly related to this area of operation."

Jan 1, 2009

By Ruhi Bux, Akshay Verma, Mohini Saxena, P. Asokan

"Due to the colossal increment in the industrialization, the generation of wastes gathered as a result of different extraction, benefaction and generation processes is having an alarming problem for waste disposal. The best and most acceptable way is to use the waste in accordance to its potential for the generation of high value lucrative composite goods. The study in this paper elucidates the potential of several industrial wastes like fly ash, red mud and marble slurry dust for the production of different wood substitute products like doors, windows, roofing sheets and instant houses for the rehabilitation on the sites of catastrophes. Wastes were initially characterized for the physical, chemical and mineralogical properties and then used in different formulations with binder like Polymer along with natural fiber like Jute to intensify the physical as well as mechanical properties of the resultant composite. The study also reveals that these composites have better mechanical properties than the available ones like teak, medium density board, Rice husk board etc. Also, the fly ash and red mud composites have better mechanical properties than marble slurry based composites. The results fosters the implementation of natural fiber with the industrial waste in the generation of eco-friendly and non-hazardous composites.IntroductionOver the last few decades, there has been a tremendous increase in the generation of industrial wastes gathered as a result of various extractions, benefaction and generation processes. The condition worsens even, when it comes to high quantum generated wastes like Fly ash, Red mud and Marble slurry dust. The primordial motif behind the incorporation of industrial wastes as filler in the development of composites is primarily composed of two main objectives; Firstly waste management, the colossal waste dissemination in the environment has disturbed the ecological balance by polluting land, surface water, ground water, air, natural resources and even disturbing the public health [1]. Secondly, to act as a perfect substitute for the conventionally existing building materials, this will aid in dwelling places to many with the least incorporation of exhaustive natural resources as woods quid pro quo."

Jan 1, 2008

By Jianxun Song, Hongmin Zhu, Qiuyu Wang, Jungang Hou, Shuqiang Jiao, Xiaobo Zhu

This work presents the results of a study on the Ti3+/Ti2+ couple redox potentials vs. Cl–/Cl2 at the temperature range (673 to 1073 K) in fused LiCl-KCl eutectic by direct potentiometric method. Initial concentrations of TiClx in solvents did not exceed 5.0 mol%. Basic thermodynamic properties of the reactions TiCl2+1/2Cl2(g)=TiCl3 were calculated using the temperature dependencies of apparent standard potentials of the couples E* Ti3+ /Ti2+.

Jan 1, 2014

By Michal Rzyman, Nakamura Takashi, Shibata Etsuro, Grabda Mariusz, Oleszek-Kudlak Sylwia

"Thermodynamic considerations indicate that heavy metal oxides should easily react with HBr, the main gaseous product from the thermal decomposition of tetrabromobisphenol A (TBBPA), forming low boiling point metallic bromides suitable for volatile separation. Mechanisms and kinetics of the bromination reactions must be well recognized prior to developing of a new treatment for the simultaneous recycling of plastic waste containing brominated flame retardants (BFRs) and metal oxides (printed circuit boards, automotive shredder residue, plating sludge, metallurgical dusts). In this work, a differential scanning calorimeter and laboratory-scale furnace were used to investigate the possibility and conditions of the bromination of ZnO by product of thermal decomposition of TBBPA. The formed solid, condensed and gaseous products were analyzed by X-ray diffraction analysis, electron probe microanalysis, inductively coupled plasma analysis, ion chromatography and gas chromatography coupled with mass spectrometry. Introduction Tetrabromobisphenol A (TBBPA) is the largest volume brominated flame retardant (BFR) in production today and is used in more than 70% of the world’s electronic and electric (E&E) appliances [1]. The growth in the production of E&E products and the fact they become obsolete so quickly cause significant problems in the safe disposal and recycling of the electrical and electric waste (E-waste) and other BFR-containing waste [2]. Among various treatment processes, thermal methods are most useful since they allow the recycling and recovery of both the organic and inorganic fractions of the waste. However, incineration of the BFR-containing wastes results in the emission of hazardous organobromine compounds, while the main portion of bromine released from decomposed BFRs is present in flue gas as hydrogen bromide (HBr) [3]. HBr, which is known to damage incineration systems, seems to be a very effective bromination agent for many metallic oxides present in waste. The concept of this study is to take advantage this of its property."

Jan 1, 2008

By M. Barkhudarov

The results are presented of research aimed at validation and development of a general purpose CFD code FLOW-3D. FLOW-3D is a commercial code developed by FLOW SCIENCE, INC. A number of physical modeling experiments involving the filling of cavities of different geometries with coloured water have been performed in order to compare the measurements with the results of computer simulations. Other numerical calculations were also done to be compared with the known analytical solutions.

Jan 1, 1992

By A. V. Tarasov

In order to improve the efficiency of hydrometallurgical processing of pyrrhotite concentrates, an integrated set of research has been carried out to investigate the use of sulfur dioxide in individual unit operations and as a leaching agent in the autoclave process as a substitute for oxygen. Treating iron-containing raw materials for production of nonferrous metals are based on the selective reaction of SO2 with iron sulfides and oxides. Iron is dissolved as sulfate, which can be treated in a separate circuit to produce iron-containing pigments or it can be disposed of after neutralization. Nonferrous and precious metals contained in pyrrhotite concentrate do not react with sulfur dioxide and remain virtually completely in the solid phase, i.e. high-grade sulfide concentrate to be treated by hydro- or pyrometallurgical methods. Elemental sulfur formed in the process of leaching is separated from the pulp in granulated form as a result of the use of special surfactants. The process of sulfide concentrate leaching with the use of sulfur dioxide is conducted at temperatures above the sulfur melting point (119°C) with distributed feeding of surfactant and under a partial pressure of sulfur dioxide of up to 0.3 to 0.5 MPa.

Jan 1, 2006

By Huanyu Zhang, Quanqiang Ma, Huiqing Tang

Improvement of the coke quality for blast furnace (BF) iron making by hydrothermal oxidation treatment on coke quality was investigated. Results show that, under subcritical condition, sulfur removal rate is 15% and the weight loss is 3%; under supercritical condition, both sulfur removal rate and mass loss rate increase with the increase of H2O2 concentration. In the experimental conditions, sulfur removal rate and mass loss rates were 45% and 17%, respectively. Hydrothermal oxidation treatment could reduce the CO2 reactivity of the coke and the treatment under supercritical condition is more effective. Hydrothermal oxidation treatment could improve the graphitization of the coke and smoothness of pore boundary in the coke and the treatment under supercritical condition is more effective.

Jan 1, 2016

By D. J. Wang

Based on the thermodynamic arid kinectic aspects, the vaccum distillation processes for the separation and recovery of metals from wastes are analyzed. As to the separation criteria, The separation coefficient and equilibrium composition relation between vapor phase and liquid phase are the bases of recovery of metals by vacuum distillation, The vaporization rates and condensation mechanisms are also discussed. Some experimental results which deal with metals-containing wastes are described and the performances of a new kind of horizontal vacuum furnace are introduced, which demonstrate that , vacuum distillation may be a prospective technique for circulation and regeneration of some non-ferrous metals from industrial wastes.

Jan 1, 1996

By P. A. Botha

The coal seams in the Waterberg basin occur in correlates of the Vryheid and Volksrust Formations as developed in the main Karoo basin. In the Vryheid Formation, five thick seams of predominantly dull coal are present, whereas a multitude of thin, lenticular seams (a few millimetres to 2 metres}, predominantly of bright coal, are developed in the overlying Grootegeluk Formation. During exploration, the coal seams were divided into 11 zones. Analytical data on float and middlings fractions (RD less than 1.40 and between 140 and 1.80, respectively} were used mainly for stratigraphic correlation of the zones in the Grootegeluk Formation. The affinities of the major and trace elements for different mineral phases and/or organic material are discussed on the basis of correlation matrices and vertical variation diagrams. Titanium and vanadium clearly show some degree of organic affinity. P 205&apos; AI203 and alkaline-earth elements are also positively correlated by the presence of goyazite in the coal. This type of investigation gives an indication of the degree to which undesirable elements like P and S can be removed during coal beneficiation, of which coal zones are unsuitable for the production of metallurgical coal on account of a high content of these elements, and to what extent the blending of different coal zones is required to keep the concentration of these elements within acceptable limits.

Jan 1, 1991

By M. Vijayalakshmi, S. Saroja, C. Sudha, T. N. Prasanthi

"Ti-5Ta-2Nb alloy and 304L austenitic stainless steel were joined by explosive cladding process. Investigations on 'as received' explosive clad revealed high hardness very near the interface due to martensitic transformation of 304L steel base plate. To improve ductility, explosive clads were heat treated in the temperature range of 823 to 1073 K for 1 to 20 h. Consequent change in the microstructure and microchemistry of the clad interface was studied. No change in the interface microstructure was observed for heat treatment at 823 K. Increase in temperature lead to the formation of various reaction zones at the interface, their number and width increase with temperature and time of thermal exposure. Growth kinetics of the reaction zones was monitored and activation energy required for formation was calculated. From elemental redistribution profiles, effective inter-diffusivities of alloying elements were calculated as a function of concentration and activation energy required for inter-diffusion was evaluated.IntroductionFor engineering components exposed to highly oxidizing and corrosive environments, a titanium based alloy i.e Ti-5Ta-2Nb (Ti-Ta-Nb) is often chosen as a structural material [1,2]. For economic consideration, vessels and piping exposed to non-oxidizing conditions are fabricated from 304L austenitic stainless steel (304L SS). Hence, dissimilar joint of Ti-5Ta-2Nb alloy and austenitic stainless steel becomes unavoidable. Fusion welding processes are not suitable for joining Ti and Fe based alloys due to the propensity for the formation of intermetallic phases and subsequent reduction in the bond strength [3,4]. Hence, explosive cladding, a solid state welding technique, was used to achieve high integrity, corrosion resistant joints between the two alloys."

Jan 1, 2012

By Weng Fu

In this study, Resin-in-Pulp (RIP) technology is used to separate Pb from a chalcopyrite slurry. Solvent-impregnated resin, Lewatit® VP OC 1026, which contains di(2-ethylhexyl) phosphoric acid (D2EHPA) in a macroporous polystyrene matrix was used, as the functional group exhibits selectivity for Pb over Cu. Adsorption pH, kinetics, as well as resin and CuSO4 concentrations were investigated. The results show that the kinetics of Pb and Cu loading are fast, reaching the adsorption equilibrium within 30 min. The equilibrium pH of 2 was chosen as optimum for operation in order to achieve a high Pb extraction rate and extent as well as selectivity for Pb over Cu. High Cu(II) concentration in solution results in Pb(II) requiring a larger amount of resin for the same degree of extraction. Regeneration and reuse tests show that the loss of adsorption capacity happens in the 1st and 2nd cycles and then the adsorption capacity stabilises for the 3rd cycle.