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By Gui-fang ZHANG, Zhe SHI, Lei GAO

Secondary V-recycling slag, an industrial waste containing high gallium is being dumped continuously, which causes the loss of gallium. Thus, the alkali fusion process was employed to recover gallium from this slag. The effects factors on extraction of gallium such as roasting temperature, roasting time, alkali fusion agent concentration and CaO concentration were investigated in the paper. The experimental results indicated that excessive roasting temperature and roasting time is unfavorable to the recovery rate of gallium. The appropriate roasting temperature and duration are 1000 and 2 hours, respectively; The appropriate proportioning of Na2CO3: NaOH is 2:1 when the concentration of alkali fusion agent weighs 0.4 times the mass of the slag; In order to remove SiO2 from the leaching liquor, CaO should be used as an additive in the roasting process. The appropriate concentration of CaO should weigh 0.2 times the mass of the slag. Employing these optimal alkali fusion conditions in the roasting process, gallium recovery is above 90%

Jan 1, 2015

By Ray Y. Lin, Sunil G. Warrier

"Low cost processing of metal matrix composites is an essential requirement for this class of materials to be acceptable in commercial application. In an effort to reduce the cost of processing of metal matrix composites, an infrared pressureless liquid infiltration technique has been developed. The salient features of infrared infiltration are that it is rapid, simple and a low cost process. The rapid processing capability causes very little oxide formation on the alloy resulting in both improved wetting and flow characteristics and reduced oxygen contamination in the composite. Thus, vacuum is normally not required. Using infrared inflltration, aluminum and titanium matrix composites have been prepared under an ambient argon atmosphere. Reinforcements in these composites include carbon fibers, silicon carbide Nicalon fibers and Textron's SCS fibers. Microstructural and mechanical test results indicate that completely consolidated composites with good fiber distribution, limited interfacial reaction and high mechanical properties can be manufactured by this process. IntroductionAluminum and titanium matrix composites reinforced with ceramic reinforcements are strong candidates for numerous applications in the aerospace and automotive industries. Aluminum matrix composites are commonly fabricated by either solid state vacuum hot pressing, liquid state pressure infiltration or squeeze casting [1]. Although liquid state pressure infiltration and squeeze casting has significant advantages over solid state processes, the requirement for pressure makes these composites uneconomical for large scale industrial application. Titanium matrix composites are primarily fabricated by solid state diffusion bonding [2]. Pressureless liquid infiltration can significantly reduce the cost of fabrication in both the composite systems. However, during pressureless infiltration processes, several complications concerning the wetting characteristics and chemical compatibility arise."

Jan 1, 1994

By P. Tapp, T. Evans, N. A. Molloy, J. Lucas

"Consideration of the protoype tuyere geometry for injection of inert gas through the bottom in a basic oxygen steel furnace and a requirement to specify an optimal flow for bottom wear and metal penetration led to experimental investigations[l,2] to apply the results of previous workers to this specific case, Flow velocity profile development within the tuyere was proposed as significant and the experimental scheme was designed to test this. It is proposed that the design criterion for the conditions of optimal flow of the prototype geometry be based on the non-dimensional mass velocity.INTRODUCTIONSharma[3] tested small diameter tuyeres in a laboratory hot model using molten iron to define a flow criterion for prevention of penetration of the bath liquid into the tuyere. Using argon, nitrogen and helium through a range of tuyeres (1 to 3 mm ill ) he proposed the jet Froude number C Fr' ) with the critical value being 2400 - 2500 or higher. Sonic or supersonic velocity was not a sufficient criterion. The tuyere design was a parallel tubular duct of moderate aspect ratio CAR) i.e. the ratio of length to diameter ranging from about 22 to 36 in the experimental furnace.Farmer et al[4] stated their their aim ""to develop a unifying explanation and procedure for the proper design of tuyeres"" but disagreed with Sharma's jet Froude number criterion. Recalculating Sharma's data they proposed instead a fully expanded Mach number of 1.75 with an initial expansion angle of ten degrees as the lower bounds of flow to meet the design requirement. They experimented with tuyeres in a water model using tubular, annular and convergent-divergent nozzles. The aspect ratio of the parallel duct tuyeres was from 533 to 762 using diameters of 1.4, 1.7 and 2.0 mm C the diameters being of tubes to be used full scale). Subsequently these results were applied to a prototype tuyere using a diameter of 1.7 mm with beneficial results in practice. This tuyere had an aspect ratio of 1067."

Jan 1, 1996

By Hideki Minoura

"Two novel electrochemical techniques for the preparation of highly crystallized CdS film have been presented. One is cathodization of a conductive substrate in an acidic chemical bath containing cadmium salt and thioacetamide, where electroreduction of proton at small current densities induces a growth of highly crystallized CdS thin films, whose growth is not disturbed by the reactions in the solution phase. The other technique is electoreduction of aqueous Cd2+— SCN complex. An advantage of this technique lies in no formation of solid particles in the bulk, of the bath.IntroductionIn recent years much attention has been paid to materials preparation by solution processing because of its advantages in lowering the cost as well as the stress to the environment, as compared to the conventional gas phase techniques which unavoidably require high temperature and/or vacuum. We have been trying to explore novel techniques for preparing functionalized compound semiconductors by aqueous solution process. Semiconductors which we have been mainly focusing on are CdS and ZnO, which are important semiconductors finding applications in various devices. In the present paper, some of the techniques that we have recently established for the preparation of highly crystallized CdS will be presented.Methods of the CdS film processing in solution phase (wet process), which have been reported so far can be divided into two major groups; one is chemical bath deposition (CBD) in alkaline solution containing Cd2+ and thiourea 1)4) and the other is electrodeposition (ED) in acidic solution containing Cd2+ and thiosulfate ions - 5)-8) or organic solutions containing dissolved sulfur 9)-11)."

Jan 1, 2000

By Alexandra Anderson

A computational fluid dynamic (CFD) model has been developed using ANSYS Fluent 17.0 to help identify areas of high wear within the refractory lining of a secondary lead reverberatory furnace. Once a base case simulation was validated using data from an operational furnace, areas of potentially high refractory wear were determined through the calculation of the temperature and velocity distributions within the furnace and on the hot face of the refractory lining. The CFD model was used to assess whether the predicted areas of high refractory wear could be minimized through changes burden geometry. The results showed that shape of the burden geometry greatly affected the overall flow patterns and heat transfer within the furnace.

By Niko Hellstén

To capture efficiently the valuable trace metals from nickel slag using electric furnace, it is important to study their distributions between the slag and metallic phases in the furnace. It is impossible to calculate accurately these distributions without experimental measurements. Therefore, in this work, selected trace metal distributions and phase equilibria between K2O containing iron-silicate slags and a metallic Ni-Fe-Cu alloy in nickel slag cleaning furnace conditions were studied. The experimental method developed and applied during the work, involved a modified quenching technique that included equilibration of the samples in semi-sealed quartz ampoules in an inert atmosphere and metallic Fe saturation. The use of the semi-sealed quartz ampoule prevents the escape of volatile elements from the sample during equilibration. Chemical compositions of the phases and the trace elements were analysed by EPMA. From the measured compositions, the trace metal distribution coefficients between the molten Ni-Fe-Cu alloy and slag were calculated.

By E. Fregeau-Wu

The major obstacle in recycling steelmaking slags to the blast furnace is their phosphorus content. Removal of the phosphorus, which is primarily associated with the silicate and phosphate phases, would allow for greater recycle of these slags for their iron, manganese, and lime contents. Calculations show that separation of the silicates from the oxide phases would remove nearly 90% of the phosphorus from the slag. The variable grain size of the as-received slag made liberation by fine grinding difficult. Therefore, slow-cooling experiments were undertaken to improve the grain size distribution. The grain size distributions were determined using in-situ image analysis. The samples were ground to their apparent liberation size and high gradient magnetic separation was used to separate the magnetic oxides from the nonmagnetic silicates and phosphates. Liberation analysis and modeling was performed on selected separation products for discussion of benefication characteristics.

Jan 1, 1995

By M. Goto, T., Matsutani, T. Igarashi

"PT. Smelting was established in February 1996 as a company to· construct the first copper Smelter and Refinery in Indonesia with US$500 million direct construction cost and operate it. The plant is located in Gresik, East Java, Indonesia and 20km northwest from Surabaya, 2nd largest city in Indonesia. The site was selected due to following .advantages.1. Adjacent PT: Petrokimia Gresik, - a fertilizer company, purchases all sulfuric acid produced through pipeline.2. Facing on the seashore of the Madura Strait, it is possible to unload copper concentrate from West Papua (3,000km from Gresik) and load granulated slag to the market.3. Close to the good harbor facilities at Surabaya for export the products.4. Gresik Industrial Area has adequate infrastructure.5. Surabaya is a quite nice city to live for people from abroad.The shareholder of PT. Smelting are Mitsubishi Materials Corporation (60.5%), PT. Freeport Indonesia (25:0%), Mitsubishi Corporation (9.5%) and Nippon Mining and Metals Co. Ltd. (4.5%).The Gresik Copper Smelter and Refinery is designed to produce 200,000 tpy of copper cathode from 660,000 tpy of copper concentrates supplied 100% by 'Grasberg Mine of PT. Freeport, Indonesia in West Papua (former Irian Jaya). Other by products are 600,000 tpy of sulfuric acid, 30,000 tpy of gypsum, 509 tpy of precious metal slime and 400,000 tpy of granulated slag. These are sold to domestic and international markets.This project adopted the Mitsubishi Continuous Copper Smelting and Converting Process in the Smelter for anode casting, Contilanod process comprising Hazelett twin belt caster and a Mannesmann's travelling shear were selected. ISA stainless steel cathode process is applied in refinery. The combination of contilanod anode and stainless steel cathode ensured good cathode quality from the very beginning of start-up SO2 gas generated from Smelter is treated by Lurgi-Mitsubishi double contact/absorption acid plant. All contact. wastewater from the plant is treated in multistage wastewater treatment plant.Electricity and oxygen are ·supplied ""over the fence"" by a company which is located in the site of the Gresik Smelter and Refinery."

Jan 1, 2000

By Lei Wang, Xiancong Zhao, Hongxu Li, Lifeng Zhang

Recovery of Fe from red mud has been studied using statistically designed experiments. The effects of three factors, namely: reduction temperature, reduction time and proportion of additive on recovery of Fe have been investigated. Experiments have been carried out using orthogonal central composite design and factorial design methods. A model has been obtained through variance analysis at 92.5% confidence level.

Jan 1, 2015

By Esperidiana A. B. Moura, Célio H. Wataya, Roberta A. Lima, Rene R. Oliveira

The purpose of this study was to investigate the mechanical, morphological and thermal properties of biodegradable composites based on aliphatic-aromatic copolyester/polylatic acid blends (PBAT/PLA blends) reinforced by açaí seed fibers, an abundant byproduct of the açaí fruit agro industry. The biodegradable polymeric composites were prepared by melting extrusion process using a twin-screw extruder machine. The fibers removed from the açaí seed were used as the reinforcement and PBAT/PLA blends as the matrix. The influence of the açaí seed fibers addition on properties of composites was investigated by tensile and impact tests, SEM, DSC, and XRD analysis. Correlation between properties was discussed. In addition, açaí seed fibers characterization by SEM, XRD and WDXRF have also been carried out. The addition of açaí seed fibers on biodegradable PBAT/PLA blends showed that it is possible to get interesting property gains in biodegradable polymer by using waste from renewable sources.

Jan 1, 2015

By S. Street

The Environment process, invented by Prof. H.K.Womer and developed at the University of Wollongong, simultaneously treats ferruginous and organic wastes via bath smelting. Conceived in the late 1980's, the patented process was originally developed using steelworks dust to settle solids from sewage, producing a composite material suitable for smelt reduction. Work began on the process in 1990 with the Australian patent having a priority date of February 1990. Early research focussed on settling of solids from sewage, while pyrometallurgical investigations examined smelting in small induction furnaces. By 1992 smelting trials had been undertaken in pneumatic and electric arc furnaces, the process being successfully demonstrated up to on 8 tonne scale. The success of this particular trial, and other smaller trials, resulted in construction of a 100kg DC arc furnace which was commissioned in 1993. By 1994 the main project focus was on development of the smelting technology. Over 3 years of trials on the DC arc furnace have identified and clarified many of the pyrometallurgical reactions. optimum operating parameters, as well as demonstrating the versatility of the process for treating a wide range of wastes. Currently the Illawarra Technology Corporation (lTC), the commercial arm of the University of Wollongong, is pursuing commercialisation of the process.

Jan 1, 1996

By Lichao Ding, Jingbiao Fan, Yunnen Chen

"With the development of industrial production, more and more wastewater containing high concentration ammonia nitrogen was discharge into the environmemt, which caused serious harm to the environmemt. Treating the wastewater has great significance to protect water resources. Using air-stripping combined with oxidation to uptake high concentration of ammonia nitrogen wastewater. The influence of operating parameters was investigated. Experimental results revealed that pH of solution, aeration time and aeration strength showed heavy influence on ammonia nitrogen removal. Air-stripping combined with oxidation can be considered as an alternative approach for the removal of high concentration of ammonia nitrogen from practical metallurgical wastewater. When pH was 11, aeration time 20 min, aeration strength 1040 Lh-1, and oxidation with 10 % NaClO solution 10 min, the initial ammonia nitrogen 2130 mgr1 could reduce to 12 mgr1. Other items could also be removed to meet the ""Integrated wastewater discharge standard (GB8978-88)"".1. IntroductionThe rapid development of human activities has caused a worldwide increase of nitrogen in rivers, lakes and coastal waters. It leads to considerable eutrophication and an increase in the frequency of toxic algae blooms [1,2]. The concentrations of nitrogen in the water of China are pervading high [3]. The discharge of wastewater containing high concentration of ammonia nitrogen is one of the most important factors. Great efforts have been devoted to the removal of ammonia nitrogen from wastewater. Traditional methods include biological denitrication [ 4 ], chemical precipitation with magnesium ammonium phosphate [5], electrochemical conversion [6], air-stripping [7] and so on. Biological denitrication is the most common process in the treatment of ammonia nitrogen wastewater. But the process is only suitable for the removal of relatively low ammonia concentration due to the requirement of appropriate C/N ratio [8]. Chemical precipitation needs additional reagents, which may introduce new pollutants to water body. Electrochemical method often uses expensive metal or metal oxide as electrodes, and also consumes large quantity of energy [6].Although air-stripping makes use of stripping tower and consumes energy, it is very suitable for the removal of relatively high ammonia concentration. Different air-stripping conditions would appear different removal efficiency. And only air-stripping the effluent can not be attained the ""Integrated wastewater discharge standard (GB8978-88)"". In this study, we use air-stripping and oxidation to removal high concentration of ammonia nitrogen from simulated and real ammonia nitrogen wastewater."

Jan 1, 2011

By A. Deneys

An experimental technique has been devised for studying the reaction kinetics of the reaction: ZnO + 2Fe0 = Zn(g) + Fe203, by which zinc evolution can occur from a molten slag bath in the absence of a carbonaceous reductant. When studying the reaction kinetics by heating from room temperature, solid state reactions and poorly defined melting points may obscure the starting point of the reaction. In order to eliminate this problem, an experimental technique was devised whereby two molten slags could be melted independently, and then mixed, to provide a well defined starting point from which to begin taking measurements. Two crucibles were mounted in a vertical reaction cylinder. The upper, mild steel, crucible had a bottom pouring plug which was sealed by a steel stopper rod. A fayalite mixture was contained in this crucible. The lower crucible contained an A12O3-CaO-SiO2-ZnO solution. Once the two slags had been melted, the steel stopper rod was removed from the upper crucible. The upper, reduced slag (fayalite in equilibrium with the upper steel crucible), drained into the lower crucible where the two slags were mixed by submerged argon stirring. Dip samples were taken to measure the zinc content of the final mixture as a function of time. The experimental procedure will be described, as well as results of experiments which were conducted on synthetic slags. The system investigated was similar to the lead blast furnace slag which is produced by the primary lead smelters of Missouri, USA.

Jan 1, 1997

By Yue-yuan Li

China has abundant magnesite resource, but the low-grade and powder ores have always been rejected, which influences the comprehensive utilization of resource and often causes circumstance problems. The present work investigated the preparation of magnesia whisker using magnesite tailings as starting materials by preparation magnesium carbonate whisker as precursor firstly in the route of calcination, hydration, carbonation and pyrolysis, follows by second calcination of the precursor. The influence of pyrolysis conditions and additives on morphology of magnesium carbonate crystal as well as the influence of calcination conditions on morphology of magnesia whisker was investigated. The results showed that thermal decomposition products was MgCO3?3H2O. Magnesium carbonate whisker with length of 10~60 µm and the length-to-diameter ratio of 10~20 was prepared when soluble magnesium salt was added. While temperature was elevated at 1°C?min-1, magnesia whisker with length of 10~60µm was obtained.

Jan 1, 2010

By Richard D. Hagni

Quantitative techniques have become increasingly important in recent years in the study of ore minerals. Precise measurement of indentation hardness and reflectance is the most important quantitative ore microscopic technique for mineral identification. Reflectance measurements of various wave lengths under monochromatic light provide the data necessary for the preparation of spectral reflectance curves and for the quantitative determination of an ore mineral's color. The procedures for the measurement of indentation hardness, reflectance, and color coordinates have recently been standardized and 204 items of quantitative data for ore minerals are now available in the first issue of the quantitative data file of the International Mineralogical Association's Commission on Ore Microscopy. A number of systems utilizing these quantitative data for systematic ore mineral identification have been published and others are in preparation. Rotation properties, although not included on the data cards, are useful in the identification of certain groups of minerals. Other aspects of quantitative ore microscopic techniques include the utilization of automatic image analysis for mineral percentage determinations and the use o~ various microbeam instruments for elemental analyses. These techniques provide a greatly improved basis for mineral identification in mineralogical and beneficiation studies.

Jan 1, 1981

By Jafar Safarian

Bauxite is the main raw material used for the production of alumina (Al2O3) through the well-known commercial Bayer process. This process has significant challenges such as limitation in using low-grade bauxites as they contain significant amounts of impurities such as Fe, Si, Ti. The Bayer process residue, which is known as red mud, is also a global environmental challenge due to huge amount of this low value residue production. An alternative sustainable process with high potential to solve these problems and produce valuable and consumable by-products is a pyrometallurgical-hydrometallurgical process in which the low-grade bauxite ore is treated through a smelting-reduction process, yielding iron alloys and a calcium-aluminate slag. Alumina is then produced from the slag by hydrometallurgical treatment. In the present work, the reduction of pellets produced from different bauxite ores by hydrogen is studied and it is shown that complete iron oxides reduction is possible. Further smelting and smelting-aluminothermic reduction of the reduced pellets show that iron and silicon ferroalloys can be produced, in addition to a proper slag for alumina extraction.

By Takashi Fujii

In the OG (Osaka Gas) process which includes a fusion process of sewage disposal sludge in coke bed knowledge of molten and fluid properties of the sludge are most important to controll the process in good condition. Thus, the softening and melting temperatures and viscosity were measured by the sessile drop technique and a rotating viscometer. Obtained results are summarized as follows: Melting character of sludge slag is varied according to their composition, but closely related to CaO/SiO2 ratio in ordinary sludge and to CaO/(Cr2O3,+Al2O3+P2O5) ratio in Cr2O3 containing sludge. Fluid property of sludge slag has a correlation with optical basicity or Riboud parameter, However, the correlation is poorer than that of metallurgical slags. Especially, chromium oxide containing sludge shows high viscosity and behaves somewhat different manner from ordinary sludge.

Jan 1, 1992

By A. Galvan

High rate compressible media filter (CMF) tests produced exceptional total suspended solids (TSS) removal at hydraulic loading rates ranging from 97.8 to 122.2 m/h. The compressible media is manufactured from a robust resin fiber that can withstand low pH and temperatures up to 149 °C. The media porosity can be varied by applying compression onto the media. At 40% compression, the CMF can remove particles greater than 4 μ. Three synthetic test-samples were generated by Hazen Research Inc., (Golden, Colorado) to simulate the copper Pregnant Leach Solution (PLS), Raffinate and Electrolyte solutions used for the testwork conducted at their facility. The preliminary results showed that the CMF was very effective in removing TSS without the use of chemical conditioning from the above test-solutions with efficiencies of 98%, 97%, and 96%, respectively. Given the remarkably high hydraulic loading rates, the industrial equipment footprint would be minimized appreciably over conventional clarification and alternative filtration systems.

By Yoshinobu Fukumori, Testuya Watanabe, Futoshi Shikata, Hiroyuki Tokumitsu, Hideki Ichikawa, Masahito Miyamoto

Nano-particulate systems have attracted much attention recently in pharmaceutical field as drug carriers and functional components of pharmaceutical dosage forms. This paper describes our approaches in design and preparation of nano-particulate systems, including lipid nano-emulsions, chitosan nanoparticles and thermosensitive acrylic nanoparticles, for certain pharmaceutical applications mentioned below. The lipid nano-emulsions with their particle size smaller than 100 nm were prepared for gadolinium neutron-capture therapy (Gd-NCT) of cancer by a thin-film hydration method with sonication, and intraperitoneally injected into Greene's melanoma (melanotic No. 179)-bearing Syrian hamsters. This provided such a high gadolinium concentraton in tumor as 107 µg/g tumor (wet basis) at 48 h after administration. As an alternative gadolinium nano-carrier for Gd-NCT, biodegradable and highly gadopentetate-loaded chitosan nanoparticles (Gd-nanoCPs, 426 mTI in particle diameter and 9.3% in Gd content) were prepared by a novel emulsion-droplet coalescence technique. A significant tumor-killing effect could be obtained when Gd-nanoCP suspension was injected intratumorally twice 24 and 8 hours before neutron irradiation into B 16Fl O melanoma-bearing mice and subsequently thermalneutron was irradiated toward tumor site with a flux of 2 x 109 n/cm2/sec for 60 min. As one another application of nanoparticles, a novel acrylic composite latex with a hydrophobic core and a thermosenstively swellable shell was designed for fabricating microcapsules showing thermosensitive mode of drug release. The microcapsules with the composite latex-dispersing membranes exhibited an exceptionally rapid on-off response of drug-release in a thermosensitive manner.

Jan 1, 2000

By Hiromichi Ohta

Precise thermal properties of molten materials are essentially required for analyzing the metal production process. These properties are also important as a clue to consider the dynamic structure of liquid materials. However, it is difficult to obtain the precise thermal diffusivity values of molten oxides at high temperature because of the experimental uncertainties arising from the bubble formation or the severe separation of radiative and conductive heat components. Recently a novel laser flash method has also developed for measuring thermal diffusivity of molten oxides at high temperature. In this new technique, the sample is melted in a metal crucible and heated to the desired temperature. A single laser pulse is flashed on the bottom of the metal crucible and the infrared ray irradiated from the same bottom surface is measured for obtaining the temperature decay, from which the thermal diffusivity of the liquid sample can be estimated. The usefulness and validity of this new laser flash technique have been confirmed by obtaining the thermal diffusivity values of silicate melts in the wide temperature range between 773 and 1673 K.

Jan 1, 2003