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By Shaik Jeelani, Esperidiana A. B. Moura, Vijaya K. Rangari, Roberta A. Lima, Rene R. Oliveira

This work present the preparation and characterization of biodegradable nanocomposites based on aliphatic-aromatic copolyester (PBAT)/polylatic acid (PLA) blend reinforced by TiO2 nanoparticle. The biodegradable polymeric nanocomposites were prepared by melting extrusion process using a twin-screw extruder machine. The influence of the TiO2 nanoparticle addition on mechanical and thermal properties of PBAT/PLA blend was investigated by tensile and impact tests, SEM, DSC and XRD analysis and the correlation between properties was discussed.

Jan 1, 2015

By San-chuan Tang, Wen Chen, Shun-ming Ning, Kan-ping Yu, Qiang Zhao, Xue-yong Xing

"A new type of desilication agent (PA-2) was selected by experiment based on the analysis of the characters of silica gel, and the influence of desilication type, desilication dosage, pH value, temperature and aging time on the desilicating effect was studied. The test results showed that on the conditions that pH was 2.0, temperature was 20""C, aging time was12 hours and the dosage of desilication agent was 0.23%, the desilication rate was higher than 93% in solution.IntroductionVanadium is an important strategic resources, which applies to steel industry and petrochemical industry. The main materials for vanadium product are steelmaking vanadium slag, stone coal and containing vanadium waste catalyst, etc. And stone coal is a low-grade carbonaceous silicified vanadium resource, which is unique material for vanadium extraction in China. Meanwhile, our stone coal reserves is No.l throughout the world.The silica acid solution containing vanadium is produced by acid leaching of raw stone coal or its roasted ore. The silica content of this solution is mostly high, besides, when pH is higher than 2 , the solution is unstable. Furthermore, it is very easy to generate gel substance with the increasing of pH value and standing time. 'Ibis silica gel is composed of colloidal particles with the size in 0.001 - 0.1 um. As a result, it is very hard even impossible for the following operation of solution."

Jan 1, 2013

By Jiann-Yang Hwang

The economic growth in new developing countries such as China and India has stimulated strong demands in basic materials such as steel. World steel production has exceeded the milestone of a billion tons a year recently. However, the blast furnace technology, which was invented in 1340 A.D., is still the fundamental route for today?s steel production. It is important to develop a new generation of steelmaking technology that can meet the society?s needs from the energy, environmental and economic standpoints in the 21st century. The new microwave and electric arc heating technology discussed in this paper provides a totally different mass and heat transfer mechanism from the conventional blast furnace technology and offers a great potential to meet our society?s needs.

Jan 1, 2006

By Osamu Iida

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

Jan 1, 1999

By Anders Salwén

In 1975 T. Nishizawa and A. Chiba reported on observed deviations from the ferrite-austenite local equilibrium in several diffusion couples based on the Fe-Cr system. In order to try to verify these results the austenite-to-ferrite transfonnation in a Fe-20 %Cr-Invalid Code [Fe-]-%Cr diffusion couple held at 1100 for 100 hours has been simulated. The simulation model is based on the postulated principle of maximum dissipation rate of Gibbs energy during transformation, which allows non-equilibrium interface conditions. Keynotes: Computer Simulation, Austenite-to-Ferrite Transfonnation, Diffusion Couple

Jan 1, 2003

By Yukihito Sasaki

Sumitomo Metal Mining Co. Ltd. planned an expansion program for the Toyo smelter and refinery in order to increase the production capacity of electrolytic copper to 450,000 tpy in 2007. Regarding the flash smelting furnace, a drastic increase in the average concentrate smelting capacity from 2,300 tpd to 3,950 tpd was required to achieve the plan. It was necessary to examine the performance of the Sumitomo concentrate burner when the feed rate was considerably increased. The authors developed a mathematical model to describe the combustion phenomena in the Toyo flash smelting furnace. This model was developed incorporating the fluid flow, heat and mass transfer, and chemical reactions of the copper concentrate and ancillary fuel. The copper concentrate was considered to mainly comprise chalcopyrite (CuFeS2). The reaction of CuFeS2 was assumed to consist of two steps, namely, the decomposition of CuFeS2 and the oxidation of the resulting pyrrhotite (FeS) and sulfur (S). The combustion phenomena in the furnace at the increased feed rate were predicted using this model. It was found that the Sumitomo burner was capable of enhancing the smelting capacity. This is attributed to the wide dispersion of the concentrate particles caused by an increase in the particle mass and a long residence time in the reaction shaft; this is due to the low temperature of the reaction air. However nonuniformity of the reaction in the reaction shaft was enhanced with the increased feed rate. In order to improve the nonuniformity of the reaction, an increase in oil-burner oxygen and an enlargement of the diameter of the dispersing cone were useful. By combining the expertise of the Toyo smelter staff and the calculation results, the concentrate smelting capacity of the Toyo smelter has been stably increased to 3,600 tpd thus far, and further improvements of the smelting performance are still being carried out.

Jan 1, 2006

By Tabbetha A. Dobbins

We report studies concerning the time frame for catalytic reactions between NaAlH4 (sodium alanate) and TiCl3 during high energy milling. Spectral features in x-ray absorption spectra were analyzed for samples milled for various times (0 minutes, 1 minute, 5 minutes, 25 minutes, and 125 minutes). A structural transition from Ti3+ to Ti0 is observed within the first 5 minutes of milling. The Ti0 structure persists for samples milled for times longer than 5 minutes?even after those samples underwent a subsequent single hydrogen desorption/absorption cycle. Samples milled for less than 5 minutes retain Ti3+. For samples milled for 1 minute, the Ti-K edge position shifts from Ti3+ to Ti0 after a single desorption/absorption cycle. However, the first coordination sphere around the Ti0 absorber occurs at longer distances for 1 minute milled sample. These results hint at the formation of Ti0 pure metallic clusters upon desorption/adsorption cycling of 1 minute milled sample. Previously reported x-ray absorption spectroscopy studies have demonstrated the structural transition from Ti3+ (in TiCl3) to Ti0(determined to be TiAl3 found at the surface of the alanate powder). Aluminum deficiency on the NaAlH4 lattice is responsible for controlling hydrogen absorption capacity. These time-resolved spectroscopy studies suggest the possibility for controlling aluminum deficiency, while still maintaining titanium activation of the alanate powder, by manipulating the coordination environment of the titanium dopant during the first five minutes of high energy milling. Specifically, a possible approach to mitigating aluminum deficiency during doping would be to introduce an alternative species to which the to Ti3+ catalyst would form a metallic bond after the TiCl3 has attached at the surface of the sodium alanate powder and before the Ti3+ forms the TiAl3 intermetallic species.

Jan 1, 2006

By M. Nienoord, O. S. L. Bruinsma, J. A. F. M. Schade Van Westrum, W. H. Sillekens, B. Mehmetaj

Recycling of aluminium is an effective way of enhancing the efficient use of energy and limiting the burden on the environment. Where cascade recycling is an established way of using reclaimed aluminium, closing the recycling chain is currently hampered by the unavailability of suitable techniques for refining contaminated scrap on an industrial scale. To overcome this problem, purification based on fractional crystallisation appears to be a promising option. This implies that the material is to be processed in the semi-solid state; that is, at a temperature where a solid and a liquid phase co-exist. In the current paper, it is shown that zone melting can serve as an indi.cative test for assessing the refining potential of fractional crystallisation processes, since they are both based on the same thermodynamic principle. Next, the results of zone-melting experiments are presented for some representative aluminium model alloys. The BPS-model (developed by Burton, Prim and Stichter) is used to interpret these results, from which it is concluded that the model needs extension to obtain a predictive tool for fractional crystallisation processes.

Jan 1, 2000

By Jin-yan TIE, Ke-xin JIAO, Qian Li, Hai-bin ZUO, Jian-Liang Zhang, Meng SHEN

This paper designs three factors such as temperature, pH, conductivity and three levels of orthogonal test. Temperature is a significant factor. However PH and conductivity are not significant through poor analysis. Further research is conducted on the temperature. Temperature stability is 50 . Suitable water velocity is 2.3m/s, which is calculated based on the largest part of the heat flux intensity and the corresponding water temperature should be controlled with 1.5. Meanwhile, water velocity increased has little effect on the heat transfer capabilities.

Jan 1, 2015

By Roger Agnew

Sulphide ores mined by Inco Limited in the Sudbury District contain small quantities of cobalt. During beneficiation, cobalt distribution to various streams is similar to nickel. After smelting, nickel is selectively extracted by carbonyl refining and the cobalt remains in the carbonylation residue. This residue is processed in a specialized hydrometallurgical plant to produce precious metal residues, copper cathodes, and a nickel- cobalt carbonate intermediate product. The nickel-cobalt is shipped to Port Colborne where the cobalt is separated as cobaltic hydroxide and refined to metallic cobalt. This paper deals specifically with the recently constructed Electro Cobalt Refinery. The cobaltic hydroxide is dissolved and residual zinc, copper and nickel are removed by ion exchange and organics by a carbon column. The purified cobalt solution is fed to the electrowinning circuit where cobalt rounds are produced on stainless steel mandrels. In the design and construction of the refinery, special attention was directed to materials of construction both for the process equipment and the physical plant, operating control and flexibility, and the quality of the working environment. The end result is an efficient and clean operation which yields a product of excellent quality.

Jan 1, 1988

By Issa S. AI-Kharusy

Oxidation/reduction (REDOX) alloy media, as used in wastewater treatment, is founded on the exchange of electrons. Because of this electron exchange, many contaminants are converted to harmless components which require no further treatment. Other types of contaminants are removed from the waste stream by electrochemically bonding to the alloy medium. This paper discusses the REDOX reactions, the role of the alloy medium in various treatment processes, and describes specific applications of REDOX alloy media for the removal and minimization of waste. The characteristics and handling of spent treatment media is also reviewed as a further consideration in waste minimization.

Jan 1, 1996

By D. D. L. Chung

"In-situ network composites are composites in which the filler network is formed during composite fabrication, in contrast to ex-situ networks which are formed prior to composite fabrication. A homogeneous in-situ network composite has the entire network at the same composition; a heterogeneous in-situ network composite has different parts of the network at different compositions. The homogeneous network composite is made either by the Method of Molten Filler Flow or the Method of Dissolution and Deposition; a heterogeneous network composite is made by the Method of Liquid-Phase Networking. Examples include polymermatrix and metal-matrix composites.IntroductionNetwork composites refer to composites containing a continuous three-dimensional network as the filler. These composites are attractive in their lack of delamination failure, which is usually characterised by two-dimensional composites. The filler and matrix in a network composite can be considered two interpenetrating networks. The mechanical interlocking of the networks adds to the cohesion of the composite. In cases where the filer is much better than the matrix in a certain property, the network nature of the filler makes the filler highly effective in improving that property in the composite in all directions. The property desired in the composite may be high strength, high modulus, low coefficient of thermal expansion, high thermal conductivity, or low electrical resistivity."

Jan 1, 1994

By Neal Schwartz, Robert De Saro, Richard Rosenthal, Ed Kear

"A Stack Melter has been installed and is currently operating at Lexington Die Casting. The Stack Melter consists of a 1 meter (3 foot) diameter refractory tube, 2 meters (7 feet) high. Specification ingots are continuously fed to the top of the melter and piled to nearly the top. A burner fires through the scrap which melts the lower portion and preheats the upper portion. As the lower portion is melted, it is drawn out and the upper preheated scrap falls to a lower level where it in tum melts. The molten metal is fed to one of two holding furnaces for eventual delivery to a casting machine.The Stack Melter's energy use is approximately 2900 joules/g (1,250 Btu/lbm), resulting in an overall energy savings of about 58%. This energy savings is brought about primarily because the flue gases preheat the scrap and the flue gas temperature is dropped to well under 528°C (1000°F)."

Jan 1, 2000

By Andrew Campbell, Michael Reed

"WorleyParsons has used Discrete Event Simulation methods in conjunction with more traditional process models to assess the performance of copper smelting operations. This work was performed to determine the plant capacities and suitability of proposed debottlenecking options including accounting for the planned and unplanned (breakdowns) shutdowns in the various parts of the plant and supply chain. This paper outlines the methods used along with demonstrating the benefits of selecting a feasible option and minimizing capital and operating costs.IntroductionTraditionally for de bottlenecking studies of smelters and other process plants, a mass balance is performed based on continuous operating rates and expected operating hours. Smelters have several points of failure that will restrict, if not take the entire plant offline. By using a more detailed model, validated against plant experience, bottlenecks can be demonstrated and strategies to remove them to increase plant availability and economic.The modeling simulates the plant performance in real time, and by performing enough simulation the expected long run performance of the plant can be estimated. The models have been built using ExtendSim which is a powerful Discrete Event Simulation software package that is ideally suited to the batch and semi-batch processes and events that occur within smelter operating environments. The value of performing this work is that the operational performance of the plant can be assessed ensuring production targets are met, without using excessive capital outlay."

Jan 1, 2013

By Chen Yongming

In order to eliminate the serious environmental pollution caused by low concentration of sulfur dioxide smoke in antimony smelters, a new smelting process, named as reducing-matting smelting, is proposed in this paper. The effects of technical conditions such as smelting temperature, smelting time, Pyrite cinder addition and the amount of additive on the smelting of stibnite concentrate have been investigated by the method of single-factor experiment. The results show that the optimum conditions are as follow: The amount of pyrite cinder is 1.2 times of its theoretical amount. The addition of soda and sodium sulfate is 15% and 72.6%, respectively, to the amount of stibnite concentrate when the total amount of sodium is 30%. The reducing-matting smelting is conducted at 1100°C for 2h then the smelting temperature is raised to 1200°C for 50min. Under the optimum conditions, the direct and total recovery ratio of antimony can gain 90.99% and 98.87%, respectively, and the fixed ratio of sulfur is higher than 99%.

Jan 1, 2006

By Michael J. Virnig

The formation of crud is a normal part of operating a solvent extraction circuit for the recovery of copper. It periodically must be removed from the circuit. This results in significant costs in terms of manpower, downtime, and loss of circuit organic. Field studies have been carried out that show that the presence of a thermodynamic modifier in the organic phase contributes to crud formation. In an effort to better understand what factors contribute to crud formation, laboratory studies involving competitive adsorption studies with model solids have been carried out. The results of these laboratory studies will be integrated with the results of the field studies to present a better understanding of crud formation.

Jan 1, 1999

By Zhuoqing An, Qi Li, Zhancheng Guo, Yanling Zhang

Fluidized bed is an important iron-making reactor, especially for the finely sized iron-bearing materials. However, defluidization caused by sticking between particles extremely limited its wide spread commercialization. In this paper, apparent viscosity was put forward to express the ability of particles to resist movement, which is reasonably considered as the comprehensive results of interaction between particles. Meanwhile, an experimental measuring method of apparent viscosity of particles was proposed, during which the torque exerted on the rotating blade in a particle layer is measured, and then the apparent viscosity is obtained based on the motion equations of powder particles. Further, the apparent viscosity of iron particles was measured by using of this method, and the effects of shape, size, and temperature were examined. The data can provide important information for understanding when and why defluidization happened.

Jan 1, 2015

By Takashi Nagai, Hideaki Sasaki, Masafumi Maeda

"The production of solar cells is increasing dramatically and the shortage of polycrystalline silicon for these cells has become a serious problem, making development of a low-cost production process for solar grade silicon essential. An electron beam melting technique is known to be effective for the removal of phosphorus from molten silicon. Although the phosphorus is removed by preferential evaporation in this process, the rate of removal is not sufficient, and its improvement requires thermodynamic information on phosphorus in the molten silicon. In this research, the vapor pressure of phosphorus in equilibrium with a siliconphosphorus alloy was measured by double Knudsen cell mass spectrometry with a system blowing gas into the Knudsen cell. The activity of phosphorus in silicon, the Gibbs energy change of the dissolution of phosphorus in silicon, and other factors were estimated from the results. Using these data, we provided guidelines on how this process can be improved.IntroductionSolar energy is in great demand since it is inexhaustible and cleaner than that from conventional energy resources. Silicon is the material most widely used to convert solar energy into electricity. Figure 1 shows the recent production of solar cells. High purity silicon for solar cells, namely solar grade silicon (SOG-Si), has been commercially supplied mainly from off-grade high purity silicon in the semiconductor industry. However, production of solar cells has increased rapidly in recent years, and the shortage of SOG-Si has become a serious problem, so that a new processes which can produce SOG-Si economically are required.Directional solidification was applied to remove transition metal elements such as Fe or Ti by segregating them from the remaining melt. However, such solidification is useless for phosphorus because the segregation coefficient of phosphorus is nearly unity. Numerous approaches have been made in an attempt to produce a resource of low cost SOG-Si from metallurgical-grade silicon (MG-Si). [1,2]"

Jan 1, 2012

By Sung Jin Han

Magnesia-based refractory is generally used in an electric arc furnace (EAF) due to its relatively high corrosion resistance and strength at high temperatures. However, the magnesia refractory is attacked by EAF slag and thus the lining life continuously decreases. Thus, it is significant to identify the interfacial reaction between magnesia refractory and FeO-rich EAF slags. In the present study, the influence of FeO-rich slag on the corrosion behavior of MgO refractory was evaluated. The (Fe,Mg)Oss layer was observed at the slag-refractory interface and its thickness increased with increasing content of FeO in the slag. The specific reaction phenomena and formation behavior of (Fe,Mg)Oss layer were evaluated by thermochemical computing program, FactsageTM7.0.

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