Search Documents

By Sevinc Yildirim, Cigdem Oruclus

"Metal-Porous Silicon (PS) based structures dipped in water show the direct hydrogen fuel cell behavior. The effect of the thickness of the cupper (Cu) film on the electrical properties of direct hydrogen fuel cell is studied by fabricating Cu/Porous Silicon/n-Silicon/Indium structures. PS samples were produced electrochemical etching of n-type single crystalline silicon with a resistivity of 1,25 Ocm and (111) orientation. The thin films of Cu with different thickness between 200 and 600 nm were deposited on PS surface by electron-beam technique. Investigation of the effect of Cu layer on the performance of the structure indicates that the performance parameters such as open circuit voltage (Voc) and short circuit current (Isc) strongly depend on the Cu layer thickness. It was observed that the divice with an 350 nm Cu layer exhibits the highest open circuit voltage (0,5 V), short circuit current (0,01 mA) and power density (10 W.m-2).IntroductionHydrogen is the most attractive and ultimate candidate for a future fuel and an energy carrier. Hydrogen is recognized as the environmentally desirable clean fuel of the future since it can be used directly in different types of hydrogen fuel cells [1]. In the past years, the rise in portable electronics requires the development of miniature fuel cells compatible with standard silicon micro fabrication technology. Most silicon micro-fuel cells have used the polyperfluo-rosulfonic acid membranes (Nafion R) as a proton exchange membranes (PEM) that is not really integrated with standard micro fabrication techniques [2-5]. The composite materials such as inorganicorganic hybrid materials (Nafion-silica, Nafion-borosiloxane etc) are next generation of proton conducting membrane [4-8]. But, fuel cells run on pure hydrogen gas, which can be produced with other energy resources. Hydrogen smallest atom and thus the H2 gas can leak easiliy. The application of hydrogen for power sources has been greatly restrained due to the lack of safe and convenient generation and storage methods.A kind of hydrogen fuel cells Metal-PS-Si structures used as an energy water directly. There is no need pure hydrogen. Cu-PS-Si Schottky-type fuel cells with as proton-conducting membrane and the thin-film cupper catalist and water as fuel, which are interesting for fabrication of lowcost miniature fuel cells. Generation of the open-circuit voltage and short-circuit current has been observed by Cu-PS-Si structure dipping in different hydrogen-containing solution."

Jan 1, 2014

By Nathanael Hudson, Ruel A. Overfelt, Sushil H. Bhavnani

"In the aerospace and automotive industries, complex shapes exist which require casting. The problem with these cast parts is the empiricism required to develop the casting process and the accompanying time and expense to develop that process.There has been an interest in using fluidized beds to allow molding sand to better encapsulate the complicated surface geometries of lost foam patterns. Fluidization coupled with a mixing jet helps to homogenize the sand through stirring and may improve the integrity of the casting.At issue is the hydrodynamics of the sand and air around the foam pattern. The commercial package PHOENlCSTM is used to simulate the flow around the pre-casting foam geometry. Employing a two fluid approach, each component is considered a fluid that interpenetrates the other phase. To this end, the kinetic theory of granular 'flow for the sand phase was incorporated into the re-compilable PHOENlCSTM code.The results of this study consist of time-averaged void fraction patterns, with voidage being defined as the fraction of air in the mixture, around the foam pattern submerged in a two-dimensional fluidized bed. The model was benchmarked against past fluidized bed experiments. In order to better understand the dependence of the void fraction pattern around the lost foam pattern, certain physical parameters are varied and the resultant void fraction maps are predicted with the model. Physical parameters such as the aspect ratio of length to width, the placement of the mixing jet, and different mixing jet velocities are varied to illustrate the dependence of the time-averaged void fraction on those variables.Results consistently indicate the presence of channeling around the lost foam pattern, with the extent of the channeling and void formation reliant to a greater degree upon the placement of the mixing jet, and to a lesser degree on mixing jet velocity and aspect ratio.The increase in radial position of the mixing jet from the bed centerline had the desirable effect of granting the churning benefits of a penetrating jet, while at the same time minimizing the formation of excess void fraction at the top of the pattern."

Jan 1, 2001

By M. Save, N. Menad

"This paper gives the overview of different alternatives to recycle the following wastes: slag, dusts, wastes of electric and electronic equipment (WEEE) and auto shredder residues (ASR). Based on modified Bogue calculations, steelmaking slags were combined in order to produce a belite-rich clinker activated with sulphoaluminate. The EAF dusts containing significant amount of metals can be recycled in different ways: The carbothermal treatment and INTECT process are reported. The results obtained from the model of Auto Shredder Residue injection into blast furnace show that ASR can be used as reducing agent in the BF process if certain conditions are met. The particle size of this material must be controlled to ensure optimal gasification of the material in raceway. The non-ferrous contents may affect the pig iron quality, which is difficult to rectify at a later point. It seems the pyrolysis is the most attractive process to handle ASR. The BRGM flow sheet of WEEE treatment is also reported.I. Introduction The activities of human been may generate wastes and by their accumulation during several years, these wastes may have an impact on the environment and on the human health. These wastes can be generated in the forms of solid, liquid and gas. A variety of industrial wastes can be recycled for use as products. There are three ways in which industrial waste recycling occurs: at the facility itself (on-site recycling), at commercial facilities that gather waste streams from several companies (off-site recycling), and at a company that uses as inputs in its production process the waste products of another company. The industries producing iron and steel may generate different solid wastes which are classified in three main categories: 1. Ferrous material (mainly dusts and sludges from gas cleaning), 2. Slags (these by-products are generated from different process stages), 3. Others by-products (including refractories and material generated from engineering activities). According to this review, the most quantity of the metallurgical wastes is deposed. Currently, the public opinion opposes the creation of new sites. This leads to the growth of the waste disposal costs. Such situation reduces the enterprise competitiveness and decreases their market share on regional and/or national and/or world scales. In these conditions, the economical activities can be decreased leading probably to social problems. The problem of wastes and/or by-products can be treated on three levels:"

Jan 1, 2008

By Baohua Li, Yanhui Liu, Shengping Li, Xuewei Lv, Yun Chen

There are almost ten billion tons of vanadium-bearing titanomagnetite in Panzhihua-Xichang area. However, iron ores in Hongge, which has the most abundant reserves in the four mine areas in Panzhihua, have not been utilized sufficiently so far. The reason behind this is the relatively high Cr2O3 in the ores (0.49 %~0.82 %), that due to its high melting temperature will negatively influence the blast furnace reduction and slagging process. Therefore, in the blast furnace process, Cr is hope to be reduced into molten iron, which can reduce slag viscosity problems. Slag iron reduction experiments were conducted to quantify the Cr reduction. Experimental results shows that with the increase of TiO2, the content of Cr in the hot metal is decreased when balanced. And during the initial stage of the reduction reaction, the reaction kinetic model is a first-order reaction.

Jan 1, 2016

By Zhongning Shi, Ramana G. Reddy, Min Li, Zhaowen Wang

Electrodeposition of cobalt from cobalt tetrafluoroborate (Co(BF4)2) was investigated using 1- butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4) ionic liquid. The experiments were conducted at 353 K. Chronoamperometry experiments confirm that the electrodeposition of cobalt on tungsten electrode proceeds via three-dimensional instantaneous nucleation with diffusion-controlled growth process. The average diffusion coefficient of Co(II) was found to be 7.5 × 10-8 cm2s-1 at 353 K, which is in good agreement with the estimated value from cyclic voltammetry. The electrochemical deposit was characterized using SEM-EDS and XRD methods. The SEM image shows formation of a dense and compact deposit at - 0.75 V. The EDS and XRD analysis confirm that the obtained deposit is pure cobalt metal.

Jan 1, 2015

By C. M. Iheagwara

An overview of the scope and ramifications of scrap recycling in the Nigerian metallurgical industries has been presented in this paper. The modern state-of-the-art processing techniques and the operational strategies employed in the recycling plants are discussed. Optimization techniques for cost effective recycling operations are highlighted. As new units within existing metallurgical plants and new metal working plants approach commercial operations, expansion of existing recycling plants and the emergence of new ones have been showing to hold the key to their profitability from the raw material standpoint. The present economic predicament of the entire industrial sub-sector, lack of sufficient foreign exchange to procure new machineries and the emergence of a maintenance culture have triggered a phenomenal increase in the number of spin-off industries which depend on metal recycling activities. This, it is argued, widens the horizon for scrap processing/recycling.

Jan 1, 1992

By Ryokichi Shimpo, Akio Fuwa

"The process-measurements of copper smelters in Japan were investigated for the summary of the latest technique and for the fundamental study of process control. The smelters investigated are those employing flash smelting furnace and P.S. converter, one reverberatory furnace and P.S. converter, and one continuous smelting converting furnace (M.I. process). Respective process is then considered, consisted of several reactors of different functions. The measurement methods were summarized in each reactor, including the measurement points. The methods of chemical analyses of the samples in each reactor were also investigated.IntroductionAn investigation on the process measurements, chemical analyses, and system control in copper smelters in Japan were carried out for understanding and summarizing the technique of the pyrometallurgical copper smelting operations. The typical seven processes in six copper smelters were investigated in the period from 1985 to 1987. The smelters investigated were Touyo Smelter of Sumitomo Metal Mining Co., Ltd., Kosaka Smelter of Dowa Mining Co., Ltd., Saganoseki Smelter of Nippon Mining Co., Ltd., Tamano Smelter of Hibi Kyodo Smelting Co., Ltd., Ashio Smelter of Furukawa Co., Ltd. and Naoshima Smelter of Mitsubishi Metal Co., Ltd. They include five flash smelting furnace and P.S. converter systems, one Mitsubishi continuous smelting and converting process (M.I. process), and one reverberatory furnace and P.S. converter system.The investigation was performed by making inquiries about the measurements, chemical analyses, system control, and their future prospects to the engineers in each smelter and by summarizing up in each item. The system control and future prospects were summarized in another paper titled ""Process Control Scheme of Copper Smelting Processes in Japan and Future View."

Jan 1, 1989

By V. V. Khristenko, V. I. Dubodelov, V. A. Seredenko, B. A. Kyryyevsky, H. V. Seredenko

"During the last decades investigators of many countries shows an increased interest to alloys which are characterized by miscibility gap in a liquid state. It is connected with essential possibilities of control of structurization in such alloys because of the melt at certain temperature parameters is · emulsion with disperse phase inclusions. These ensure essential influence ·on structurizations.The certain inclusions can play a role of lubrication ensuring ""wearless"" process. The sizes of inclusions of this phase can be rather large proportional to sizes of strengthening phase (up to 1000 nm). Other inclusions ensure process of strengthening of a main material. In this case requests to a dispersibility character of distribution and structure of such inclusions are much higher.The multicomponent alloys of system of copper - (Fe - Cr - C)- alloy concern to the number of advanced compositions. The copper alloys with structure of a type of a ""frozen emulsion"" in which strengthening phase· is a chromium pig-iron are characterized by high thermal stability in the extreme operating conditions. The mechanism of inclusions forming is emulsifying of a melt in miscibility gap at temperatures close to temperature of binodal under superimposition of external effects.The main complexity of producing of ware from such alloys is .a providing in their structure of necessary dispersible inclusions uniformly distributed all over the volume. Thanks to a selective action of electromagnetic fields on liquid phases with various electroconductivity relative velocity of phases is created and is regulated the ratio of their ""apparent"" specific gravity is changed. Excitation of pulsing force effects with the certain frequency on interphase surface allow actively to influence on process of a dispersion of a liquid metal medium."

Jan 1, 2000

By G. Bjorling

After complete dissolution of chalcopyrite concentrate in sulphuric acid in presence of nitric acid the excess of the latter is expelled by a surplus of concentrate and the last traces of nitrate removed in the mother liquor after crystallization of the copper and iron sulphates. Zinc accumulates in the mother liquor from which it can be removed by solvent extraction of zinc sulphate as a pair of ions. After dissolution of the sulphate crystals in water the neutral solution is oxidized in an autoclave at 140°C where iron sulphate is thermally hydrolyzed; the iron-free solution is taken to copper electrowinning and the cell acid after partial evaporation recirculated with the mother liquor to the leaching circuit. Total recovery of copper is about 96%; other metals like zinc and iron are concentrated in industrially usable products. At a copper price of about 70 c/lb, the method appears to be profitable also in a small unit.

Jan 1, 1976

By C. B. Solnordal, R. N. Taylor

"The heat transfer conditions on the outer side of a Sirosmelt lance have been determined using experimental measurements in combination with a mathematical model. By measuring the temperature distribution along the wall of an operating Sirosmelt lance, as well as the thickness of the slag layer on it, it was possible to use the model to determine both the heat transfer coefficient between the vessel contents and the lance, as well as the effective thermal conductivity of the slag layer. The effective thermal conductivity of the slag layer was found to be within the range 0.7-1.3 W.m-1. ºCl, which was in good agreement with measured values for magnetite. The outside heat transfer coefficient varied from 80 to ISO W.m-2. ºC1, which was smaller than quoted in the literature for metal/slag systems. The discrepancy was attributed to the high thermal resistance experienced between the lance wall and the slag layer, as well as the large quantities of combustion gases that envelop the lance tip and reduce convection and conduction from the melt to the lance. INTRODUCTIONThe Sirosmelt submerged combustion smelting process [1] utilizes top injection lances to deliver fuel and air into a metallurgical melt. To help prevent lance failure from attack by liquid slag, helical vane swirlers are used within the annular lance to impart swirl to the flowing air and enhance the heat transfer from the lance wall to the air. The swirlers thus cool the wall, and enable a frozen layer of slag to form on its outer surface. This solid layer ensures liquid slag cannot reach the lance surface, and the lance is protected.A mathematical model of the heat transfer processes associated with the lance has been developed, which combines heat balance equations with engineering correlations to predict the wall and cooling air temperature of the lance, as well as the air pressure distribution. An account of the model was given by Rankin et al. [2]. To further enhance the model and enable it to predict the thickness of slag accumulating on the lance, a detailed analysis of the heat flow through the slag layer commenced in 1992. By far the most complex aspect of the model, the flow of heat from the vessel contents to the outside of the lance was dependent on many factors, including:-"

Jan 1, 1996

By Tarek M. Abd El Hamid, Suzane Ali

"Treatment of industrial waste materials is created serious problem in Egypt. Aluminium sludge is generated as a by-product from aluminium household industry which contains significantly high alumina content exceeding 90%. This by-product randomly disposed and creates serious environment problems to locate community. To develop the treatment process of this material, the recovery of high purity alumina and identify the potential application is being the primary objective, This paper represents the recovery process of alumina process waste sludge High purity alumina material <99.8% aluminium oxide with originate particle size 0.125-0.420mm and apparent density 0.39g/cm3 was obtained with a specific surface area 139m2/g. Alumina produced was modified by cerium oxide doped alumina. The catalytic activity and selectivity was investigated in conversion of iso-propanol via dehydrogenation reaction yielding only acetone indicating an excellent selectivity the dehydrogenation. The presence of 10% CeO2 increase in the catalytic activity of 82% for the originated alumina. Introduction Approximately 20 thousand tons of aluminium waste produced in Egypt in 2006 with increasing amounts expected in succeeding years. A part of this waste contains organics impurities which coexisted with aluminium waste as a result of manufacture final aluminium products, waste usually content <1 to 2 wt% of organic carbon. It's generally admitted that the organic species are present in the form of lubricant oils used in rolling and pressing equipments for aluminium sheet. Both industry and government face possible high-cost disposal problems that more magnified by large volume of waste produced. The alumina recovery leachable study conduct in this paper had the following objectives: 1- Develop a process that can provide an environmentally acceptable residue and also recover the available alumina. 2- Evaluate the alumina produced in terms of grade and catalytic application."

Jan 1, 2008

By André L. de Vegt

Soil and groundwater beneath a zinc production plant in The Netherlands are contaminated with metals and sulfate. To avoid contamination of nearby drinking water aquifers, a hydro-geological containment system and a biological treatment plant for the extracted ground water have been installed. Currently about 5000 m3/day of groundwater is extracted from a combination of 12 shallow and deep wells. Heavy metals and sulfate have to be removed from the extracted water before it can be discharged into a river. Several water treatment methods have been studied and pilot tested at the site. The preferred and selected process is based on the activity of sulfate reducing bacteria (SRB) and combines sulfate removal and heavy metal removal in one single installation. Anaerobic bacteria reduce sulfate to sulfide resulting in the precipitation of metal sulfides. Excess sulfide Is biologically converted to elemental sulfur. A full scale biological treatment system was started up in May 1992. Design, start-up, commissioning and operational experiences are reported in this paper. Concentrations of metals and sulfate in the SRB water treatment plant effluent are well within the limits set by the Dutch Authorities for discharge to surface water.

Jan 1, 1995

By Y. K. Rao

Relatively pure crystalline lead sulfate (PbSO4) can be produced by chemical vapor transport from an impure source such as the lead-acid battery paste or the roast-ore-leach-residue from a hy¬drometallurgical process-route. In a closed-reactor, transport of matter is induced by a tempera¬ture-gradient and the steady-state transfer rate can be calculated using the data on the standard free energies of formation for the species present and the pertinent binary diffusion coefficients. The present work focusses on chemical vapor transport in a tubular reactor (1.4-cm inner diameter x 10-cm long) with the source- and deposition-ends held at 850°C (T,) and 750°C (Td), respectively; PbC12(g) is the &apos;solvent&apos; or &apos;transport agent&apos; and NiSO4(s) placed in the source-zone -serves to maintain a sufficiently high S0,-potential such that the stability of the lead sulfate species is ensured. For the purposes of analysis, the gas-phase in the reactor is assumed to consist of eight species: H2O, PbC12, SO3, SO2. O2 HO, C12, and PbC14. The reaction between C12(g) and PbSO4(s) in the high-temperature source-zone produces PbCl2, SO2, and 02; four more reaction-equilibria in the same zone yield other species. In the low-temperature deposition-zone, reaction equilibrium involving PbC12, H2O, and SO, leads to the nucleation and growth of PbSO4 crystals; three other reaction-equilibria occur in this zone. By employing the virtual equilibrium state for the end-zones and coupling it to the Stefan-Maxwell diffusion equations for each of the gas species, the respective partial pressures for these, in the source- and deposition-zones, are computed at steady-state. From these data, the molar fluxes of PbCl2. PbCl4, and so forth, are determined. Allowing for the transport-enhancing effects of thermal convection, the net transport rate of lead (or PbSO4) is duly calculated for specified initial conditions. The predicted rates show very good agreement with measured rate data reported in the literature [ V. Plies, T. Kohlmann and R. Gruehn: Z. anorg. allg. Chem, 568, 62 (1989)

Jan 1, 1995

By Gang Qi

The solubility of nitrogen in pure molybdenum was measured over the temperature range 2173 to 2473 K and up to one atmosphere (101 kPa) of nitrogen gas pressure. Both thermochemical and kinetic aspects of this phenomenon were considered in this study. The solution of nitrogen in molybdenum may be expressed by the reaction 1/2N2(g) = {N} (Mo,s), for which the standard Gibbs energy is given by the expression {A}G° = 78,500 + 27.36T Joules/g atom N. The formation of molybdenum nitrides, specifically Mo2N, was considered. Attention was also focused on the mechanism of nitrogen solution in molybdenum. Estimates of the diffusivity of nitrogen atoms in solid molybdenum were derived from the kinetic data.

Jan 1, 1991

By Jie Li, Shu Yang, Zhongliang Tian, Xun Hu, Yanqing Lai

The purity of the electrolyte has an important influence on the content of the impurities in electrodeposited silicon. In this paper, effects of electrolysis temperature, current density and the time on the concentrations of two important impurities: phosphorus and iron in the electrolyte were investigated during the purification of Na3AlF6-10%K2SiF6-AlF3 melt. It was observed that the concentrations of P and Fe in the electrolyte decreased with the electrolysis temperature, current density and the electrolysis time increasing. X-ray fluorescence (XRF) of the electrolyte shows that the concentrations of P and Fe decrease from 4.2ppmw to 1.3ppmw and 204.0ppmw to 42.6ppmw, respectively. The removal rates of P and Fe are 69.08% and 79.12% when the electrolysis was performed for the duration of 3 hours and at a current density of 20mA·cm-2 while the operating temperature was 1225K.

Jan 1, 2015

By Ma Ying

The continuous directional solidification technique of five kinds of special ZA alloys with eutectic, peritectic and eutectoid transfonnation under the condition of continuous casting by heated mold was studied. The mechanism of surface defects appearing in ZA alloy line was discussed and the structure of some defects were analyzed by SEM. The results show that only when the fitting of various technique factors, pressure head, outlet temperature, pulling speed and cooling condition are reasonable under a certain range, can the ZA alloy smooth line be continuously pulled out. Unreasonable techniques will result in hot tear, rough surface, mush outlet, leaking and other defects. The shape and location of solid-liquid zone have an important influence on the formation of the above defects. When the solid-liquid zone is located in the mould outlet or inner mould, the surface of solidification will protrude into the inner mould. If the remaining liquid cannot counteract the solidification contraction, a rough surface will appear. If the solidification surface further into the mould, the ingot in the mould will have a great friction force when pulling and will form a hot tear. When the solid-liquid zone is moved out of mould, the solidification surface will turn into a plane, which easily results in leaking. A vibration or unstable operation will cause an ingot winding during pulling.

Jan 1, 2003

By Dong Liu, Zejian Yang, Yong Li, Tao Jiang, Xiangxin Xue, He Yang

"The structure, composition, morphology, and adsorption property of UV-vis light of as-prepared samples were characterized using XRD, SEM, FTIR-EDS, and UV-vis DRS. UV-visible light induced photocatalytic degradation of methylene blue ~) over Ti02-doped diopside was investigated. Experimental results show that doping Fe + induced the formation of Ti-0 or Ti-0-Si in diopside, and promoted the light adsorption property of diopside. Photocatalytic reactivity of Ti02-doped diopside obviously depended on content of doping Ti02. The diopside with 3% Ti02 exhibited the superior photocatalytic activity with 76% degradation of methylene blue under light irradiation for 3 h.IntroductionPhotocatalytic technology has been extensively studied in the process of dealing with inorganic and organic pollutants. Ti02, with its own non-toxic, stable, low-cost and other advantages, has become the most widely studied photocatalytic materials[l-SJ_ The low utilization quantum made it restricted in the practical application. SrTi03 as the representative of the perovskite[9·121, Bi2W06 for the composite oxide[13,141, also attracted wide interest in the photocatalytic studies. However, these photocatalytic material has been mostly prepared in relatively strict experimental conditions with chemical reagents, they had small production, high cost, which made them difficult for practical applications.In our country, there has 400 million tonnes of ti-bearing blast furnace slag (TBBFS) each year in the process of smelting pig iron, which has lead to waste of titanium resources and pollution of the surrounding environment. In recent years, studies have shown that TBBFS instead of pure Ti02 to be photocatalytic materials is feasible[ 151. TBBFS has not only been higher photocatalytic degradation activity for the o-nitrophenol, methyl orange, nitrobenzene and other organic matter[16-191,but also exhibited excellent in the process of dealing with inorganic heavy metals in waste water (containing Cr6+i201. If TBBFS can be successfully applied to photocatalytic technology, the will make large accumulation of titanium-bearing slag reasonable used, so as promote the re-use of energy. At present, our understanding of the photocatalytic activity of TBBFS is steadily deepening. Photocatalytic activity ofCaTi03 has been reported as one of the main minerals ofTBBFS [21'21J, However, there were few studies for Another major mineral of TBBFS - diopside which had the content of9-15%. diopside would doped with Ti02 In the process of smelting pig iron, therefore, Ti02-doped diopside's photocatalytic activity in the UV-Vis was mainly studied in this paper."

Jan 1, 2013

By Honglei Zhang, Wuguo Xiang, Xinhao Huang, Guotao Xu, Xilai Chen

"The service behavior of refractories used in hot air pipeline for hot air stoves in a 3200 M3 blast furnace of WISCO was analyzed. The damage factors can be concluded as the poor quality of and alusite based bricks, the severe thermal shock damage, the more porosity in structures, loose bonding capability, and the unreasonable choice of materials and design of bricks. By analysis, the service life of hot air stoves can be enhanced by the measurements such as the reasonable choice of materials and their match, the use of light-weight refractories, the improvement of brick type, etc. Thereafter, the normal production operation of hot air stoves is guaranteed.IntroductionThe No.7 blast furnace of WISCO has been used for about 5 years and it was mid-repaired in March, 2012. The top phenomena of worn hot air pipelines are brick drop, breakage, severely local wear and deformation, existing hidden danger, so the worn hot air pipelines were renewed. Investigations have been done on the stove damage and design [1,2]. In order to clarify the wear mechanism, the used refractories for hot air pipelines were sampled and analyzed, the properties and structures of worn materials and reused materials are relatively studied."

Jan 1, 2013

By Shaohua Ju, Jin-hui Peng, Ya-jian Wang, Shuai-dan Lu, Li-bo Zhang, Lei Guo

"The granulation of a red mud is of great importance for recycling this material as an adsorbent for waste water or gas. A new granulating process was developed and its effect was evaluated. To reduce the cost of the granulation process, the wet filter cake (containing 25% water) was directly mixed with different cement contents (4%, 6%, 8% and 10% based on wet material). The mixtures were placed in a moist environment for 4 days, and then were washed with deionized water until the pH values of leachants were lower than 9.0. The efflorescence ratio, surface area and particle size of the aged mixture were determined, respectively, by bottle shaking experiments, N2 adsorption and screening. The results showed that the best addition of cement is 2%, and this yielded granulated material with a particle size of less than 2 mm, an efflorescence ratio of 4.83% and a specific surface area of 17.42 m2/g.IntroductionRed mud is a residue of the aluminium industry that is produced during the alkaline extraction of alumina from bauxite by the Bayer process. For every ton of alumina that is produced, the amount of red mud generated can vary from 0.3 to 2.5 tons, depending on the characteristics of the bauxite. In its typical form, red mud is brick red in colour, caustic, about three times as dense as water and, when un-neutralised, has a high pH, typically around pH 13 [1]. It is primarily composed of iron oxide, silica and alumina, along with traces of heavy metals. Red mud particles are quite small; typically 99% will pass through a 0.6 mm sieve and 87% through a 0.038 mm sieve [2],"

Jan 1, 2012

By A. Slotwinski, R. E. Barry, M. M. Menon, P. T. Spampinato

"A coherent FM laser radar based sensor for remote metrology of plasma facing material surfaces in a fusion reactor is described. The sensor is capable of 3-D mapping of surfaces, based on a series of precise range measurements from large distances (up to 20 m). Other features include the ability to operate under adverse environmental conditions involving very high gamma radiation (3xI04 Gy/hr), ultra-high-vacuum (<I0-5 Pa), and high temperature (200°C). The paper describes the basic principles of the sensor, together with experimental results obtained with the sensor. The ability of the sensor for remote rendering of ""visual quality"" images without the need for any external illumination is also illustrated.IntroductionMeasurement of the features of large area surfaces (-1500 m2) to sub-millimeter accuracy, from relatively large distances (20 m), is necessary in the case of the International Thermonuclear Experimental Reactor (ITER -a 1500 MW fusion reactor that is currently in the design phase). Furthermore, the measurements may have to be performed after the reactor is temporarily shut down. During such shut-downs, the ITER in-vessel environment will be highly radioactive due to neutron activation of the reactor wall (gamma radiation field of 3xl04 Gy/hr), the vessel will be maintained under ultra-clean vacuum conditions (<10-5 Pa), and the plasma facing surfaces will be maintained at elevated temperature (200°C). Therefore, the precision measurements must be conducted remotely, and because of the large dimensions of the fusion reactor and the limited number of access ports, the measurements must be done from large distances. The reactor vessel is a large toroid. Fig. 1 shows the cross section of the toroidal vacuum vessel, and the location of the metrology probe. Because of the very large surface area involved, fast scanning capability is also needed to reduce the reactor down-time."

Jan 1, 1997