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By K. Robinson

Following the longest Smelter campaign in BCL?s history it was planned to completely rebuild the flash smelting furnace in 1987. This was the fourth major overhaul and the most extensive so far attempted. Detailed planning took place over several year$ preceding the shutdown and implementation was completed in 54 days. The key to minimising shutdown time was the method designed for installation of the new uptake shaft and reaction shaft. Major repair work was also undertaken in the waste heat boiler and electric furnaces. Both of these activities had an impact on the critical path of the flash smelting furnace overhaul.

Jan 1, 1993

By D. M. Hausen

Microscopic point-counting of polished sections, in combination with x-ray diffraction analyses of representative whole rock samples, provides an efficient means to compare the modal mineralogic composition of different rock types. Major gangue minerals, e.g., quartz, feldspars, micas, amphiboles, chlorite, clays, etc., are estimated semiquantitatively by x-ray diffraction techniques, utilizing optimum grind, gridded sample surfaces and a sample spinner during scanning. Opaque to semi-opaque oxide and .sulfide phases are estimated by microscopic "point-count" and "gross-count" scanning. Total mineralogic compositions are calculated and normalized to 100 percent from XRD and microscopic data by computer programming. Comparative mineral analyses for different rock types, as well as quantitative microscopic data for various parameters, including particle and crystal sizes, textures, degree of alteration, paragenesis, etc., provide useful guides in mineral exploration, both in early stages of geologic mapping and later stages of economic evaluation. Several case histories are described.

Jan 1, 1981

By C. J. Newman

The Kidd Creek Copper Smelter has been expanded from its original design of 59,000 tonnes of copper per year to over 120,000 tonnes per year. Modifications to the process gas handling system and acid plant have been made to accommodate this higher production rate and to generally optimize the operation. The gas handling system associated with the continuous smelting process is discussed in terms of boiler accretions and modifications to minimize their impact on operations; design changes to effect reductions in high pressure drop duct configurations; material changes to overcome corrosion and plant additions to improve gas cleaning capability. The acid plant is reviewed with references to changes? made to accommodate the increased SO2 gas strength resulting from the higher smelting rates.

Jan 1, 1992

By Bing Gao, Zhe Wang, Xiangdong Xing, Xueqi Zhang, Shan Ren, Jianliang Zhang

"In sintering, the flame front speed (bed permeability) and sinter qualities are greatly depended on the feed size, especially coke breeze and limestone particle size. It is well known that coke breeze provides sinter bed with heat to meet the demand of partial fusion and diffusion bonding while limestone reacts with iron ore to generate bonding phase in the sintering process. Accordingly, it is necessary to find the optimum combination of different particle size of coke breeze and limestone to yield sinter associated with better qualities. In this study, sinter was produced in the sinter pot with varying coke breeze and limestone particle size together in sintering of a coarse hematite iron ore. The sintering productivity was measured and all of the result sinters were examined by microstructure analysis and reduction degradation test (RDI test). For the sintering of a coarse hematite iron ore, it was found that the optimum mean particle size combination of coke breeze and limestone was 1. 71mm and 1.55mm in the sinter mix. On such a circumstance, sintering productivity was higher and the properties of sinter were better.IntroductionNowadays, as the main iron bearing burden material of modem blast furnaces, sinter has a great influence on the blast furnace operation. Sintering is a greatly complex process involving various chemical reactions to form kinds of mineral phases [1, 2]. In the sintering process, coke breeze is used for fuel and it generates heat to raise the green bed temperature. Limestone serves as flux and it reacts with iron ore to produce various mineral phases. On one hand, during the sintering process, the particle size of coke breeze can have an effect on temperature, atmosphere, the flame front speed and all of them act on the microstructure and mineral constitutions of sinter [3, 4]."

Jan 1, 2013

By P .. R. Ammann

A two-stage pyrometallurgical process has been developed for the recovery of copper (and other non-ferrous metals) from copper smelter slags. All types of slags, including highly oxidized, converter-type slags, are cleaned in an electric furnace which employs mechanical mixers to promote magnetite reduction and copper extraction at high rates. In a 10-ton pilot furnace, it has been demonstrated that slags can be cleaned to 0.2-0.3 per cent copper with economically acceptable usage of raw materials and energy; copper is recovered as a high-grade matte. Pilot plant data have been scaled up to a commercial furnace and engineering designs have been made for a furnace to treat 60 tons per hour of slag from a Noranda Reactor and the associated converters. Plans are being formulated for the construction of a prototype slag cleaning furnace.

Jan 1, 1976

By R. J. St. Eloi

The Kidd Creek Copper Smelter has been expanded from its original design of 59,000 tonnes of copper per year to over 120,000 tonnes per year .. Modifications to the process gas handling system and acid plant have been made to accommodate this higher production rate and to .generally optimize the operation. The gas handling system associated with the continuous smelting process is discussed in terms of boiler accretions and modifications to minimize their impact on operations; design changes to effect reductions in high pressure drop duct configurations; material changes to overcome corrosion and plant additions to 'improve gas cleaning capability. The acid plant is reviewed with references to changes made to accommodate the increased S02 gas strength resulting from the higher smelting rates;

Jan 1, 1992

By Lijun Liu, Yingwei Li, Jianhua Liu, Jinhui Peng

"As essential equipment in the metallurgical industry, current air heat exchangers cannot meet the requirements of high temperature heat transfer. In this paper, an energy efficient air heat exchanger, based on accumulation of the heat generated by microwave absorbing materials, is presented according to heat transfer theory and principles of the microwave field. A tubular shaped heat exchanger was designed and built up through temperature-rising curve, and experimental research of microwave high-temperature air heat exchangers was carried out. It was found from experiments that the tubular shaped heat exchanger fabricated using material B could be used for high temperature heat transfer system, and equilibrium temperatures could reach up to 457—485?.IntroductionHeating or cooling of air by heat exchangers is commonly practiced in a wide range of industries including construction, chemical, machinery, textile, printing, and dyeing [1-3]. Generally such heating or cooling of air is achieved in pipe heat exchangers. There are several drawbacks for such heat exchangers, namely, (i) the limitation of temperature to which the pipes can be heated, (ii) tendency to oxidize at high temperature, and (iii) poor strength of metallic pipes at high temperature. These limitations do not allow pipe heat exchangers to be operated at high temperatures [4-6].Microwave heating of inert solids, which are stable at high temperature, is a possible solution to achieve high temperature of the medium in air heat exchangers. It is well-known that microwave heating is an efficient, clean, safe, easy-to-control heating method. Microwave heating utilizes the dielectric and magnetic properties of a material. When microwaves penetrate and spread into the dielectric material, electrons, ions, etc move in the internal electromagnetic field, while the elasticity of inertia and friction impede these movements. This results in a significant thermal effect, increasing the surface temperature rapidly [7-8]. This paper studies mainly design and experimental research of microwave high-temperature air heat exchanger."

Jan 1, 2011

By Zhenjun Tan, Lei Zhang, Jigang Li, Yifang Zheng, Jilai Xue

"Water electrolysis in 0.4 mol/L NaOH solution for hydrogen generation was carried out with ultrasound introduced through the anode. It was found that the cell voltage reduced by 150-300 mV in the current range of 20 mA to 40 mA with ultrasound frequency at 25.3 kHz. The cell operation became unstable when the cell current was larger than 75 mA with ultrasound. This reduction in cell voltage was due to removal of the gas bubbles on the electrode surface, which can be directly observed in the see-through cell of water electrolysis. Ultrasound with frequency of 33.3 Hz was also tried, but no better effect was obtained. The results suggest that ultrasound assisted water electrolysis can have potential in energy savings for hydrogen production.IntroductionIn electrolytic process, the electrode that the bubbles generated on its surface usually covered a thin gas film, which can be caused an additional voltage about 0.15-0.25V[l,2], especially in aluminum electrolysis. To solve the problem, loading the ultrasound removes the gas bubbles from the electrodes, this subject had been researched in recent years. From 1995 Jilai Xue et al[3,4,5]. applied the ultrasound in aluminum electrolysis in lab. The results from Sheng-De Li et al.[6] reveals that can decrease the cell voltage and have influences about the hydrogen and oxygen's output ratio. Although there are many paper about the applying of ultrasound such as in electrolysis[5,6], deposition[7,8], plating[9,10], oxidation of salts substance on the surface of electrodes[l 1] and so on, the effect of different frequencies ultrasound hadn't been investigated deeply.We focus on the anode voltage by different frequencies ultrasound and the bubble behaviors in this paper. The environment of this experiment is in alkaline solution. Through this exploration it can offer a basis for the applying of ultrasound in electrolysis."

Jan 1, 2011

By Clemens Schmetterer, Patrick J. Masset

"The surface tension represents an important property for the modelling of high temperature processes. In this study the surface tension of two Al2O3 – CaO – SiO2 model slags and the influence of the admixture of 5 up to 30 wt.% FeO were studied. The surface tension measurements were carried out using the sessile drop technique on BN substrates under Ar atmosphere (10-6 atm O2) up to 1500 °C.IntroductionThe aim of VIRTUHCON1 is the virtualization of high temperature conversion processes, a task that requires thorough understanding of these processes. In many of these conversion processes slag plays an important role to control the properties of the product, to protect the reactor lining or simply as waste. Slag surface tension is one of the materials properties that is needed for the description of such processes, since it influences the interactions between the components in the reactor, e.g. at the slag – Fe interface in the blast furnace.Surface and interfacial tensions have thus received considerable attention in research, but the number of investigations in this particular pseudo-quaternary system is surprisingly low. Furthermore, the literature data are subject to different measurement conditions and techniques which complicates the data analysis and comparison.The slag atlas [1] offers a compilation of the available literature until 1986 (shown in Table I), but literature search has not revealed more recent studies of this system until now. For example, Elliott and Mounier [2] determined the surface tension of ACSF slags using the double tube maximum bubble pressure technique at 1200 °C. They kept their slags in contact with Cu-S-F mattes, and the slag therefore contained a certain amount of sulphur which acts as a surfactant and lowers the surface tension. The compositions of their slags were scattered over a wide composition range and they did not use a common ACS base mixture for their tests, either. The surface tension values vary between 417 and 446 mN/m, but due to the reasons just mentioned no trend in the measurements can be observed and the influence of FeO admixture on the surface tension cannot be deduced. Further information including the temperature dependence is available from Pavlov et al. [3], Ishchanov and Shushkov [4] and Murav’eva and Kaplun [5]; the diagram on page 446 in Ref. [1] has been drawn from these sources. Both positive and negative temperature coefficients are reported in these works. SiO2 is the only pure constituent that has a positive temperature coefficient [6], but a correlation of the temperature coefficient with the SiO2 content was not found to be conclusive."

Jan 1, 2011

By William Petruk

Mineralogical and image analysis studies have been performed on four volcanogenic base metal ores that contain 0.01 to 4.5 wt% Pb to determine the behaviour of galena during mineral processing. The galena in these ores is fine grained and is poorly liberated in both the primacy and regrind mill discharges. Consequently, low grade Pb concentrates are produced to obtain relatively high Pb recoveries. The Pb concentrates contain many impurities including high amounts of pyrite and sphalerite, and small amount of CU-, As-, Ag-, Bi-, and Se-sulfides. These impurities need to be rejected from the Pb bullion during smelting. The galena commonly contains up to 1 wt% Ag in solid solution with an average of 600 to 1460 ppu for the deposits studied to date. The Ag in galena accounts for up to 65% of the Ag in some ores.

Jan 1, 1990

By Chen-Ming Kuo, Esher Hsu

"The importers and manufacturers who import or produce products with packaging containers are charged a recycling fee in Taiwan. The amount of waste packaging containers used for calculating the recycling charge is based upon the amount declared by importers and manufacturers which might be underestimated. This study aims to estimate the amount of waste packaging containers generated by households in Taiwan and also explores its distribution. The sampling survey and ratio estimation are conducted for estimating the recycled amount; while the refuse sampling method for municipal solid waste composition is employed to estimate the un-recycled waste packaging containers. The estimated total amount of waste packaging containers in 2011 generated by households in Taiwan is 696,511 m.t., of which, 79.49% of the waste packaging containers were recycled and 20.51 % were landfilled or incinerated. This study shows that the amount of waste packaging containers declared by importers and producers is underestimated around 20%.IntroductionWaste packaging containers including iron cans, aluminum cans, glass bottles, plastic containers, paper containers, aluminum foiled paper packs are officially announced to be recycled in Taiwan. In order to create the economic incentive for raising recycling performance, associated manufacturers and importers are charged a recycling fee to subsidize recyclers. The amount of packaging containers declared by importers and manufacturers is used for calculating the recycling charge and recycling rate. The importers and manufacturers might underreport their producing (importing) amount to pay less recycling fees. Therefore, the estimated waste packaging containers based upon the amount declared by importers and manufacturers is usually underestimated. Related previous studies about waste packaging containers recycling in Taiwan are done by Hsu and co-workers [1-4]. Hsu and Kuo [1] estimated total production values of recycling and evaluated the performance of recycling performance based upon the estimated production values. Hsu and Liu [5] provided a cost analysis of recycling for waste packaging containers in Taiwan. Bor, Chien, and Hsu [2] presented a market-incentive recycling system for waste packaging containers in Taiwan. Hsu and Kuo [4] provided an amending mechanism for product charge and recycling subsidy in response to the social economic changes for waste packaging containers recycling. Lee and Hsu [ 6, 7] explored the distribution, fee rates, and collection rate of waste containers. This study aims to estimate the amount of waste packaging containers generated by households in Taiwan and also explore its distribution."

Jan 1, 2014

By P. Louis

Although cobalt is known and used for its hardness and wear resistance, ductile cobalt can be obtained by electrolysis in chloride solutions, under the following conditions : pH : 1.5 - 2, Co++ : 30 - 60 g/l, current density : 100 - 500 A/m2, temperature 40 - 70°C. No explanation was found for the ductility of the deposit under these conditions. Indeed the ductile P (FCC) cobalt and the hydrogen contents in the cobalt deposits are nearly the same as those obtained in a sulfate media, which gives brittle depo¬sits under equivalent electrolysis conditions. Malleable cobalt sheets can be easily obtained under the proposed conditions which could lead to new applications for cobalt.

Jan 1, 1988

By Adele Garkida

Compacts of crushed waste window glass, fluorescent tubes, drinking glasses and laboratory glass wares were made at various proportions from 106 microns and minus 75 microns powders in combination with 5% bentonite as binder for each glass type, after several trials to determine compatibility of particle sizes. They were made using the uniaxial press at 10,000 psi and sintered at a temperature range of 700- 750oC. The results showed anisotropic shrinkage behavior for all the samples, exhibiting an axial shrinkage lower than the radial shrinkage. Sintered compact from waste drinking glass which comprised of 60% 106 microns and 40% minus 75 microns powders showed the least sintering shrinkage factor of 1.125, fused at 700oC and the highest shrinkage factor of 1.286 obtained at 750oC. This shrinkage behaviour connotes that sintering can be employed to utilize these waste glasses up to the maximum of 95% recycled glass content in ceramic tile production.

Jan 1, 2008

By M. Yoshida, S. Hanada, T. Takasugi

"A study has been conducted to examine the effect of ternary alloying elements on high temperature deformation of the C15 NbCr2 based intermetallics in Nb-Cr-X (X=V, Mo and W) alloy systems, which have attractive properties as high temperature structural materials. The high temperature deformation of the C15 NbCr2 intermetallics can be improved by two alloying methods. One method is based on geometrical consideration for site occupation and atomic size factor of component elements and additive elements in the single phase C15 lattice; addition of Mo and V can promote dislocation movement without introducing significant hardening. The other method is based on microstructural modification through ternary alloying; moderate addition of these elements results in a variety of duplex microstructure consisting of the C15 phase and bee solid solution without forming any intermediate phases, and can enhance the high temperature deformability. Particularly, alloys with duplex microstructure equilibrating with Cr-rich bee solid solution is shown to exhibit superior deform ability. Also, lattice property of the additive atoms in the C15 structure and phase relation between the C15 structure and the bee solid solution are investigated by OM, XRD, TEM and ALCHEMI observations and then discussed in association with observed mechanical behavior.IntroductionLaves intermetallics with AB2 stoichiometry belong to the largest group in a large number of intermetallics with various kind of crystal structures, and have a variation of the cubic CIS, the hexagonal C14 and the dihexagonal C36 structures, depending on stacking sequence of XYZ type, each of which consists of four interpenetrating atomic layers (1-3). Some of the Laves intermetallics have good functional properties and therefore are considered to be used as, for instance, magnetic materials, magneto-optical materials, hydrogen storage materials and superconducting materials (2). Also, the Laves intermetallics are considered to be good candidate as high temperature structural materials operating at high temperatures and in severe environment because they have high melting point, low density, and potential resistance to corrosion and oxidation. However, the Laves intermetallics are very brittle at low temperatures because they consist of complex crystal structures similar to many other intermetallics."

Jan 1, 1996

By Selvin Yesilay, Munevver Caki, Canbora Bayraktar, Bekir Karasu, Rahmi Imrak

"In this study, the utilization capability of the solid wastes taken from a commercial roof tile and brick factory in Eskisehir of Turkiye has been investigated in the production of stoneware bodies which can be formed by slip casting. At the first stage, X-ray fluorescent (XRF) and X-ray difractometer (XRD) analyses of the wastes were performed. Depending upon the results, a body recipe with an optimum casting concentration was adjusted. The bodies obtained from prepared slips were fired at 1160 oC as glazed and unglazed forms. Then, they were undergone certain tests in order to determine their firing shrinkage values, water absorption levels and optical parameters. To establish what kind of phase formations occurred after firing as a result of waste incorporations into bodies XRD analysis was conducted. Additionally, effects of such a compositional modification on the microstructure of the bodies were examined by a scanning electron microscope (SEM). Consequently, it was concluded that fired roof tile and brick wastes could be evaluated in both glazed and unglazed stoneware bodies. Introduction Stoneware is the general name applied to many wares fired between 1150 and 1300 °C. It has a different and denser structure than those of ceramics produced at lower temperatures. Fired stoneware possesses a lower water absorption value. When matured at a high temperature, it gives a possibility for the use of feldspar as a main ingredient [1-2]. Colors of stoneware can be brown, red, white and most of the times beige. Firing usually takes place in oxidation atmosphere but also reduction can be rarely used. This naturally has an effect on the body colors [3]. Earth, which contains clay minerals, becomes plastic mud when mixed with water, has a capability to be easily shaped and can be hardened without cracking if fired at 900-1000 °C, is referred as one of the brick and tile raw materials [4]. Natural and aesthetic appearances of buildings obtained with brick and tile products, which make them preferable especially for construction sector, are of importance. Because clays being main raw material of that type of productions generally do not exist as pure materials in nature, their usability depends on their mineralogy and impurities they contain [5]."

Jan 1, 2008

By Ali Kucuk, Bekir Karasu, Keriman Karaveli Pekkan

"Zircon (zirconium silicate) is the main opacifier of glossy, opaque, white colored, frit-based wall tile glazes. However, zirconia containing frits employed in the preparation of these glazes increase the production cost and therefore, limit zircon usage as a raw material at industrial scale. With the present study, it was searched whether borax solid wastes could be evaluated as a component in the starting relevant frit recipes. The wastes were obtained from Eti Maden Kirka Boron Company of Turkiye. Frit production, glaze preparation, application, and fast single-firing of glazed wall tiles were conducted under laboratory working conditions in Anadolu University, Department of Materials Science and Engineering laboratories. Beside standard tests applied to the final glazed wall tiles, color and gloss analyses of the fired glazes were conducted with a spectrophoto-meter and a gloss-meter. Characterization of these newly produced glass-ceramic glazes was made by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy dispersive X-ray (EDX) techniques. IntroductionFrits are the indispensable constituents of most industrial glazes which mature at temperatures below 1150 °C [1]. In the traditional opaque glazes used in wall tile industry, opacity usually originates through hardening of glass matrix by adding high amounts of zirconia containing frits into the glaze batch [2]. Nowadays, researches point out that certain type of glass-ceramic layers can be alternatively employed as tile coatings lowering the use of zirconia containing expensive opaque frits. A rather high crystallization capacity of glass- ceramic glazes due to zirconia presence in glass network makes them suitable candidate as a glaze coating with a desirable micro-structure. One of the best methods to obtain an opaque glaze surface is to induce a crystal phase in the coating, whose refractive index differs significantly from that of the glassy matrix. The opacity of such coating is determined by the diffusion, refraction and reflection of light through the layer containing emerging crystals, and the degree of opacity mainly depends on the size and quantity of crystals. The development of glazes not consisting of expensive or toxic components is of special interest [3]."

Jan 1, 2008

By K. J. Cathro

A hydrometallurgical process is described for the recovery of copper from chalcopyrite concentrates. The process is based on a cupric chloride leach, the concentrate having first been "activated" by heating it with sulphur at a temperature near 400°C. This activation process converts most of the iron of the chalcopyrite to pyrite, which is insoluble in the cupric chloride leachant. The copper is converted to the mineral idaite, which dissolves readily in hot cupric chloride: at 106°C, 98% of the copper is extracted in a three-stage countercurrent leach, the leaching tirqe being 1 hour per stage. The sulphur of the chalcopyrite appears as elemental sulphur, which is recycled for the activation of further concentrate, the final leach residue consisting of pyrite, plus the gangue present in the original concentrate. The copper extracted can be recovered by electrowinning, using a diaphragm cell. Current efficiency (one-electron basis) is about 70% but the cell voltage is only about 1 V, so that power consumption is three times lower than for the conventional sulphate electrowinning process. The leachant is simultaneously regenerated in the anode compartment. The behaviour of minor elements in the concentrate has also been studied.

Jan 1, 1976

By Djalma Souza, Rubén Sánchez, Regina Maria Pinheiro, Carlos Maurício Fontes Vieira, Sergio Neves Monteiro

"This work has for objectives to characterize a waste generated in the form of sludge during the treatment of the effluent of a paper making industry and to evaluate the effect of its incorporation up to 10 wt.% on the properties of a clayey body used for brick production. For the characterization of the waste the following techniques were used: X-ray diffraction, X-ray fluorescence, differential thermal analysis and termogravimetric analysis with mass spectrometry. Specimens were prepared by uniaxial pressing at 20 MPa before firing at 750 °C. The physical and mechanical properties evaluated were: linear shrinkage, water absorption and flexural rupture strength. The results showed that, in agreement with the characteristics of the waste, its recycling into red ceramic can contribute to decrease the consumption of fuel during the firing stage. However, the waste changes the physical and mechanical properties, generating a deleterious effect on the water absorption and flexural rupture strength of the ceramic.IntroductionAccording to the Brazilian Association of Pulp and Paper, in the last 10 years, the global production of paper grew 35%. Brazil produced 8,2 million tons of paper in 2004 and held the position of the seventh largest world manufacturer of pulp, with about 9,4 million tons per year [1]. The pulp and paper industry generates effluents that present problems related to their disposal, even after the treatment. Among the solid wastes generated by this industry, the main waste is the primary sludge from the effluent treatment plant (ETP).After the initial treatment the decanted solids go through a dewatering stage, generating the solid form denominated primary sludge. This sludge resembles a paper paste of dark gray color when humid, and clear gray color when dry. This primary waste is composed basically of kaolin, pulp, traces of chemical substances and water. This waste generated in the pulp and paper industry depends on the characteristics of the process and of the employed techniques. It can vary significantly from one industrial unit to another, even in the case that the final products are similar. Its composition is approximately 60% of kaolin and 40% of pulp, and these percentages can vary in some moments as a function of the process [2,3]."

Jan 1, 2008

By Kampe. S. L., Baker. Andrew H., Tony Zahrah

"Experimental heats of reaction for the formation of several Al3Ti + TiB2 intermetallic composite formulations have been determined utilizing bomb calorimetry. To overcome the kinetic constraints and achieve ignition in these formulations, a boron (B)/potassium nitrate (KNO3) initiation aid was incorporated within the blended reactant compact. The heat contribution from the initiation aid was regressed to provide estimates of the heat of reaction of the nominal formulations. Powder x-ray diffraction was utilized to identify the products of the reaction and discern any differences between the predicted equilibrium products of the formulation and the actual products.IntroductionReaction synthesis is a technique for the creation of ceramics, intermetallics, and in-situ composite materials [1]. Reaction synthesis is defined by its self, propagating mechanism, where the energy liberated from a localized reaction within a green powder compact is enough to carry the bulk reaction to completion. Achieving a self, propagating state can be achieved in variations of two primary methods of initiation: uniform volumetric heating and directional propagation [2].Uniform volumetric heating involves subjecting a green compact of the unreacted formulation to uniform heating in a furnace to encourage diffusion to initiate the reaction (Figure 1a) throughout the bulk material. Directional propagation utilizes a point heat source at one section of a green compact of unreacted formulation (Figure 1b). The localized exothermic reaction at one point in the compact then initiates the reaction in the section of the compact adjacent to it and fully propagates throughout the entire compact until completion. Initiation of the localized reaction is generally associated with the melting of the constituent with the lowest melting point, with instantaneous initiation of the reaction usually occurring close to that melting point [1]. This melting point can be high in some systems of interest, such as the titanium (Ti) and boron (B) system in equation 1:"

Jan 1, 2011

By Peng Jianping, Feng Naixiang, Di Yuezhong, Wang Yaowu, Pan Xijuan

A vacuum silicon thermal reduction lithium process is developed in present work which used lithium hydroxide, alumina and calcium oxide as raw materials. The process contains two steps, which are that Li5AlO4 clinker is prepared in ambient environment, and that metal lithium is extracted from Li5AlO4 clinker with ferro-silicon alloy as reductant in vacuum. On the basis of thermodynamic analysis and investigative experiments, feasibility of this process is proved. The results show that Li5AlO4 can be generated by calcination lithium hydroxide and alumina, the burning loss is above 31% under the conditions of calicination temperature above 750℃ and time more than 90min. The main phases of calcination product are Li5AlO4 and CaO. When the calcination product is reduced by ferro-silicon alloy in vacuum, the lithium reduction ratio can be over 80% under the conditions of reduction temperature 1200℃ and reduction time 60min.

Jan 1, 2014