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Synthesis of substitutional hexaboride of lanthanum and cerium La_(1-x)Ce_(x)B_(6) via aluminothermic reduction

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Journal of Rare Earths 2023年第11期41卷 1780-1788,I0005页

作者： Yu Wang Xiao-Hui Yang Jian Cui Guo-Hua Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China Beijing Key Laboratory of Green Recovery and Extraction of Rare and Precious Metals University of Science and Technology BeijingBeijing 100083China

Rare-earth hexaborides(REB_(6))are vital raw materials for cathode materials and high temperature structural ceramics that are widely applied as high-frequency electron tubes and ceramics adaptive for extreme environment,*** this work,single phase substitutional solid solution REB_(6)(LaB_(6),La_(0.75)Ce_(0.25)B_(6).La_(0.5)Ce_(0.5)B_(6),La_(0.25)Ce_(0.75)B_(6) and CeB_(6))powders were prepared with the raw materials of La_(2)O_(3),CeO_(2),B_(4)C and Al powders,after calcining at 1773 K for 4 h and the following alkaline *** substitutional solid solution products have homogeneous distributions of La and Ce in *** microscopic morphology analysis,it is discovered that the formation of solid solution is beneficial for reducing the particle size of product,relative to LaB_(6) and CeB_(6).Moreover,Al flux plays an important role in decarbonizing reaction,and C contents of all products are below 0.4 wt%.

关键词： Hexaboride Substitutional solid solution aluminothermic reduction Rare earths

Effect of magnesium on the aluminothermic reduction rate of zinc oxide obtained from spent alkaline battery anodes for the preparation of Al–Zn–Mg alloys

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International Journal of Minerals,Metallurgy and Materials 2016年第4期23卷 458-465页

作者： Rocio Ochoa Alfredo Flores Jesus Torres Cinvestav-Saltillo

The aluminothermic reduction of zinc oxide（ZnO） from alkaline battery anodes using molten Al may be a good option for the elaboration of secondary 7000-series alloys. This process is affected by the initial content of Mg within molten Al, which decreases the surface tension of the molten metal and conversely increases the wettability of ZnO particles. The effect of initial Mg concentration on the aluminothermic reduction rate of ZnO was analyzed at the following values： 0.90wt%, 1.20wt%, 4.00t%, 4.25wt%, and 4.40wt%. The ZnO particles were incorporated by mechanical agitation using a graphite paddle inside a bath of molten Al maintained at a constant temperature of 1123 K and at a constant agitation speed of 250 r/min, the treatment time was 240 min and the ZnO particle size was 450？500 mesh. The results show an increase in Zn concentration in the prepared alloys up to 5.43wt% for the highest initial concentration of Mg. The reaction products obtained were characterized by scanning electron microscopy and X-ray diffraction, and the efficiency of the reaction was measured on the basis of the different concentrations of Mg studied.

关键词： aluminothermic reduction alkaline batteries zinc oxide waste utilization aluminum zinc magnesium alloys

Kinetics of extracting magnesium from mixture of calcined magnesite and calcined dolomite by vacuum aluminothermic reduction

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Transactions of Nonferrous Metals Society of China 2014年第3期24卷 839-847页

作者：傅大学冯乃祥王耀武彭建平狄跃忠东北大学材料与冶金学院沈阳110819

The vacuum aluminothermic reduction of the mixture of calcined magnesite and calcined dolomite was studied. An isothermal reduction method satisfying the vacuum aluminothermic reduction was proposed. The experiments were carried out at 4 Pa. The results indicate that the reduction rate is increased with increasing temperature, content of aluminum and pellet forming pressure. The XRD patterns of pellets at different reduction stages confirm that the reduction process can be roughly classified into three stages：the formation of MgAl2O4, and Ca12Al14O33 phases;the phase transformation from MgAl2O4 and C12A7 to CaAl2O4;the formation of CaAl4O7 phase. The experimental data were divided into three parts according to the kinetic models. The apparent activation energies of the three parts were determined to be 98.2, 133.0 and 223.3 kJ/mol, respectively.

关键词： Amagnesium kinetics aluminothermic reduction magnesite dolomite

Mechanism of extracting magenesium from mixture of calcined magnesite and calcined dolomite by vacuum aluminothermic reduction

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Transactions of Nonferrous Metals Society of China 2014年第8期24卷 2677-2686页

作者：傅大学王耀武彭建平狄跃忠陶绍虎冯乃祥东北大学材料与冶金学院沈阳110819

The process of aluminothermic reduction of a mixture of calcined dolomite and calcined magnesite had been developed. The mechanism of the process was studied by SEM and EDS. The reduction process was divided into three stages:0≤ηt/ηf≤0.43±0.06, 0.43±0.06≤ηt/ηf≤0.9±0.02 and 0.9±0.02≤ηt/ηfreduction ratio at time t and the final reduction ratio obtained in the experiment at temperature T, respectively. The first stage included the direct reaction between calcined dolomite or calcined magnesite and Al with 12CaO·7Al2O3 and MgO·Al2O3 as products. The reaction rate depended on the chemical reaction. The CA phase was mainly produced in the second stage and the overall reaction rate was determined by both the diffusion of Ca2+ with molten Al and the chemical reaction. The CA2 phase was mainly produced in the third stage and the reaction process was controlled by the diffusion of Ca2+.

关键词： magnesium aluminothermic reduction magnesite dolomite mechanism

IMPROVEMENT ON DEOXIDATION EFFICIENCY OF MOLTEN IRON WITH MAGNESIUM VAPOR PRODUCED IN-SITU BY aluminothermic reduction OF MAGNESIA

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IMPROVEMENT ON DEOXIDATION EFFICIENCY OF MOLTEN IRON WITH MA...

Spatial phase structure and oxidation process of Al-W alloy powder with high sphericity

International Symposium on Global Environment and Steel Industry(ISES’03)

作者： Jiayi SHAN Takashi ITOH Kuniyuki KITAGAWA Masamichi SANO Research Center for Advanced Energy Conversion Nagoya University Japan Research Center for Advanced Energy Conversion Nagoya University Japan Research Center for Advanced Energy Conversion Nagoya University Japan Professor Emeritus of Nagoya University Japan

＜正＞A novel method of the deoxidation of the molten iron has been proposed with in-situ production of the magnesium vapor by aluminothermic reduction of magnesia. A reaction model has been developed to examine the rate controlling mechanism and highly efficient deoxidation with the magnesium vapor. The model calculation results show that, in order to achieve the high efficiency, control of the magnesium vapor pressure in the injected bubble is essential.

关键词： deoxidation molten iron magnesium vapor aluminothermic reduction clean steel.

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Journal of Materials Science & Technology 2022年第19期114卷 62-72页

作者： Aobo Hu Shuizhou Cai State Key Laboratory of Material Processing and Die&Mould Technology The School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China

In this study,Al-30W(wt.%)alloy powder was prepared by aluminothermic reduction and hightemperature gas *** then studied the phase composition,surface morphology,spatial phase structure,and thermal oxidation process using XRD,SEM/EDS,TEM,DSC,and DTA/TG *** results showed that the Al-30W alloy powder exhibited high sphericity,and the interior presented a special spatial phase structure in which the Al/W amorphous alloy phase and the metastable Al/W intermetallic compound phase were distributed in the pure Al *** the Al-30W alloy powder was stabilized in a vacuum tube furnace,the spatial phase structure of the alloy powder changed,and a small amount of pure Al was embedded in the Al_(12)W *** resulting Al-30W alloy powder products,treated in air at different temperatures,were collected in situ and *** results presented that with an increase in temperature,the types and morphologies of the Al/W intermetallic compounds in the Al-30W alloy powder ***,the Al-30W alloy powder began to undergo intense oxidation reactions at about 900℃,accompanied by a concentrated energy release and rapid weight *** volatilization of WO_(3)produced in the oxidation process promoted the complete oxidation of the Al-30W alloy powder,and the Al-30W alloy powder was completely oxidized at 1300℃.At this stage,all W atoms were transformed into gaseous WO_(3),and only a large number of small Al_(2)O_(3)fragments remained in the oxidation ***,the Al-30W alloy powder exhibited excellent thermal reactivity and oxidation integrity,and may offer excellent application prospects in the field of energetic materials.

关键词： aluminothermic reduction High-temperature gas atomization Al/W amorphous alloy phase Metastable Al/W intermetallic compound phase Thermal oxidation process

In situ formation of Zr_2Al_3C_4/Al_2O_3 composites by combustion synthesis with PTFE and thermal activations

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Transactions of Nonferrous Metals Society of China 2018年第10期28卷 2011-2016页

作者： Chun-liang YEH Yi-Chang CHEN Department of Aerospace and Systems Engineering Feng Chia University100 Wenhwa RoadSeatwenTaichung 40724TaiwanChina

Preparation of Zr2Al3C4-Al2O3 in situ composites was investigated by self-propagating high-temperature synthesis(SHS)involving both aluminothermic reduction of ZrO2 and chemical activation of PTFE(Teflon).The starting materials included ZrO2,Al,carbon black and *** addition to the conventional SHS method,the experiments were conducted by a chemical-oven SHS(COSHS)route to thermally assist the synthesis *** threshold amount of 2%(mass fraction)PTFE was required to induce self-sustaining *** the conventional SHS scheme was utilized,due to low combustion temperatures between 1152 and 1272°C and insufficient reaction time,the dominant carbide forming in the composite was ZrC instead of *** the other hand,the COSHS technique increased the combustion temperature of the reactant compact to about 1576°C,lengthened the high-temperature duration for the reaction,and prevented Al vapor from escaping *** a consequence,Zr2Al3C4-Al2O3 composites with a small amount of Zr3Al3C5 were *** microstructure of the COSHS-derived product showed that plate-like Zr2Al3C4 grains were about 2μm in thickness and 10-30μm in length,and most of them were closely stacked into a laminated configuration.

关键词： Zr2Al3C4 combustion synthesis PTFE activation chemical-oven SHS aluminothermic reduction

The Role of Preliminary Mechanical Activation in the Process of Obtaining Pow-der-Like Ferrosilicium from Metallurgical Slags

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Journal of Surface Engineered Materials and Advanced Technology 2016年第2期6卷 11-17页

作者： Vilena Hakob Martirosyan Marine Eduard Sasuntsyan Department of Chemical Technologies and Environmental Engineering National Polytechnic University of Armenia (NPUA) Yerevan Armenia

Powder iron monosilicide with certain structure exhibits magnetic properties and can be used as an alloying additive in the production of electrical steels and silicon alloys with special physical and chemical properties. From this point of view, development of the energy-saving technology for receiving such a valuable alloying agent with the disposal of secondary waste is an urgent task. For this purpose, the method of joint aluminothermic reduction of preliminary mechanically activated metallurgical waste is offered. Recently, a method for combining the self-propagating high-temperature synthesis and preliminary mechanical activation for obtaining metal powders with certain phase composition and structure is considered as one of the efficient ones. As the initial materials for obtaining iron monosilicide, the waste (or converter) slags of the Alaverdi copper-smelting plant and molybdenum slags of the Yerevan Pure Iron Plant are used. Besides the mentioned slags, NaNO3 and CaO are added. Properties and structure of the received silicide depend on the contents, quantity of components, and the mass relation of two wastes in the burden. Therefore, the processes of structure formation of the iron monosilicide received from metallurgical waste are investigated. Studies have shown that the best results are obtained in case of waste and molybdenum slag relation of 4:1, when the 60-minute grinding in the vibromill leads to a significant increase in the mechanical activation of the burden. At this relation of FeO and SiO2, a condition is created for receiving iron monosilicide showing magnetic properties. On the whole, those transformations lead to a decrease in the reaction activation power of the interacting substances, an increase of the reactivity capacities, as well as to a new original course of reactions and new modified materials.

关键词： Mechanochemical Activation Copper Concentrate Silicon Concentrate Slag Grinding Vibromill aluminothermic reduction