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Deoxidation of Molten Steel by Aluminum

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Journal of Iron and Steel Research International 2015年第10期22卷 905-908页

作者： guo-hua zhang Kuo-chih CHOU State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

The deoxidation equilibrium of liquid steel was investigated from a new perspective. Dissolved associate MmOn was used to describe the interaction between dissolved M and dissolved oxygen instead of the interaction parameter of Wagner. The concentration of unassociated oxygen could be considered as the activity of oxygen. Or, the percentage of unassociated oxygen in the total dissolved oxygen was the activity coefficient of oxygen. When the content of deoxidizer was low, the dissolved oxygen was mainly composed of the unassociated oxygen, while more and more MxO formed with gradually increasing M content. The present model gave a good description to the aluminum deoxidation equilibrium after considering AlO and Al2O. Furthermore, the higher the con- tent of A1 was, the higher the content of Al2O relative to the content of AlO would be.

关键词： deoxidation equilibrium activity coefficient associated oxygen unassociated oxygen interaction coefficient

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

Viscosity and Structure Changes of CaO-SiO_2-Al_2O_3-CaF_2 Melts with Substituting Al_2O_3 for SiO_2

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Journal of Iron and Steel Research International 2016年第7期23卷 633-637页

作者： guo-hua zhang Yu-lan ZHEN Kuo-chih CHOU State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

During the smelting process of the high Al steels,the reaction between SiOin molten slag and dissolved aluminum in liquid steel always takes *** aluminathermic reduction reaction will lead to the substitution of 1mol SiOfor 2/3mol ***,the investigations about the influence of the ratio of AlOto SiOon viscosity and structure changes of mould flux during this process are very *** viscosity variation of CaO-SiO-AlO-CaFv2 melts was studied by changing compositions considering the aluminathermic reduction *** was found that viscosity increased monotonously with gradually increasing the substitution *** to the Raman analysis,the substitution of AlOfor SiOleads to the decrease of non-bridging oxygen but the increase of bridging ***,degree of polymerization and viscosity increase as the substitution extent *** comparing the measured viscosities with the model calculated values,it was found that both the recently developed zhang′s model and Roboud model could describe the viscosity variation behavior of CaO-SiO-AlO-CaFmelts very well.

关键词： high aluminum steel CaO-SiO_2-Al_2O_3-CaF_2 viscosity Raman spectrum mould flux

Regulation of Ti(C,N)deposition on hot surface of refractory in blast furnace hearth

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Journal of Iron and Steel Research International 2024年第6期31卷 1423-1435页

作者： Jian Cao Cui Wang Jjan-liang zhang Ke-xin Jiao guo-hua zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083China

Ti(C,N)concentration was found to be lower on the hearth sidewall of a blast furnace and increased gradually toward the bottom of the blast *** Ti(C,N)protective layer in a blast furnace is ***,the formation of a Ti(C,N)protective layer was promoted by studying the heterogeneous nucleation principle of titanium compounds on different substances and regulation measures for the deposition process of titanium compounds on refractories or *** lattice disregistry between the titanium compounds and the main components in the refractory or the main impurities in the protective layer was calculated using a two-dimensional disregistry equation to study the heterogeneous nucleation principle of titanium *** results revealed that in refractory materials,the heterogeneous nucleation of carbonitride is weak when C,SiO_(2),and Al_(2)O_(3) are used as heterogeneous nucleation substrates,and the heterogeneous nucleation of carbonitride is strong when TiO_(2) and SiC are used as heterogeneous nucleation *** nucleation phases,TiC,TiN,Ti(C_(0.3),N_(0.7)),and Ti(C_(0.5),N_(0.5))have similar heterogeneous nucleation ability in single component refractory,and the type of carbonitride has little effect on the lattice *** impurities in the protective layer as the substrate phases are not conducive to the heterogeneous nucleation of *** CaS was used as the substrate phase,the heterogeneous nucleation ability of carbonitride was the *** carbon and alumina were not conducive to the heterogeneous nucleation of carbonitride,but carbon was more unfavourable than alumina.

关键词： Ti(C,N) Lattice disregistry Lattice constant Heterogeneous nucleation Regulation measure

Synthesis of high-quality ferrovanadium nitride by carbothermal reduction nitridation method

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Journal of Iron and Steel Research International 2021年第3期28卷 255-262页

作者： Ying-cong Zhou Yu Wang Kuo-chih Chou guo-hua zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China

High-quality ferrovanadium nitride(FeV45N,FeV55N and Fe65N)was fabricated using the raw materials of Fe_(3)O_(4),V_(2)O_(5) and graphite via carbothermal reduction nitridation *** with the traditional methods,it shortens the production process of ferrovanadium nitride by avoiding the preparation of *** effects of C/O molar ratio and reaction temperature on phase transition,density,carbon,oxygen and nitrogen contents and microstructure were *** appropriate C/O molar ratio is crucial to obtain the products with high nitrogen *** is also found that a higher temperature is beneficial for the densification,and the density of the products obtained at 1550℃ is much higher than that at 1500℃.Moreover,a higher temperature contributes to the increase in nitrogen content owing to the higher reaction *** carbothermal reduction nitridation method is proved to be a facile route to fabricate cost-effective ferrovanadium nitride and is possible to be applied for industrial production.

关键词： Ferrovanadium nitride Carbothermal reduction nitridation High nitrogen content Densification

Preparation of CaB6 powder via calciothermic reduction of boron carbide

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International Journal of Minerals,Metallurgy and Materials 2020年第1期27卷 37-45页

作者： Yu Wang guo-hua zhang Yue-dong Wu Xin-bo He State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for Advanced Materials and Technology University of Science and Technology BeijingBeijing 100083China

The method of calciothermic reduction of B4C was proposed for preparing *** phase transition and morphology evolution during the reaction were investigated in *** experimental results reveal that Ca first reacts with B4C to generate CaB2C2 and CaB6 at a low temperature and that the CaB2C2 subsequently reacts with Ca to produce CaB6 and CaC2 at a high *** the products were leached to remove the byproduct CaC2,pure CaB6 was *** grain size of the prepared CaB6 was 2–3μm,whereas its particle size was 4–13μm;it inherited the particle size of *** residual C content of the product was decreased to 1.03 wt%after the first reaction at 1173 K for 4 h and the second reaction at 1623 K for 4 h.

关键词： borides carbides particle size powders calcium hexaboride

Non-isothermal reduction kinetics of titanomagnetite by hydrogen

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International Journal of Minerals,Metallurgy and Materials 2013年第12期20卷 1134-1140页

作者： Jie Dang guo-hua zhang Xiao-jun Hu Kuo-chih Chou State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

Reduction of titanomagnetite （TTM） powders by H2-Ar gas mixtures was investigated under a non-isothermal condition by using a thermogravimetric analysis system. It was found that non-isothermal reduction of TTM proceeded via a dual-reaction mechanism. The first reaction was reduction of TTM to wustite and ilmenite, whereas the second one was reduction of wiistite and ilmenite to iron and titanium dioxide. By using a new model for the dual reactions, which was in an analytical form and incorporated different variables, such as time, temperature, particle size, and hydrogen partial pressure, rate-controlling steps for the dual reactions were obtained with the apparent activation energies calculated to be 90-98 and 115-132 kJ/mol for the first and second reactions, respectively.

关键词： titanomagnetite ore reduction hydrogen reaction kinetics

Study on reduction of MoS_2 powders with activated carbon to produce Mo_2C under vacuum conditions

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International Journal of Minerals,Metallurgy and Materials 2018年第4期25卷 405-412页

作者： guo-hua zhang He-qiang Chang Lu Wang Kuo-chih Chou State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

A method of preparing Mo2C via vacuum carbothermic reduction of MoS2 in the temperature range of 1350–1550°C was proposed. The effects of MoS2-to-C molar ratio（a, a = 1：1, 1：1.5, and 1：2.5） and reaction temperature（1350 to 1550°C） on the reaction were studied in detail. The phase transition, morphological evolution, and residual sulfur content of the products were analyzed by X-ray diffraction, field-emission scanning electron microscopy, and carbon–sulfur analysis, respectively. The results showed that the complete decomposition of MoS2 under vacuum is difficult, whereas activated carbon can react with MoS2 under vacuum to generate Mo2C. Meanwhile, higher temperatures and the addition of more carbon accelerated the rate of carbothermic reduction reaction and further decreased the residual sulfur content. From the experimental results, the optimum molar ratio α was concluded to be 1：1.5.

关键词： vacuum treatment carbon thermoreduction molybdenum minerals molybdenum carbide microstructure

Dripping and evolution behavior of primary slag bearing TiO2 through the coke packed bed in a blast-furnace hearth

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 130-138页

作者： Yan-xiang Liu Jian-liang zhang Zhi-yu Wang Ke-xin Jiao guo-hua zhang Kuo-chih Chou State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Baogang Zhanjiang Iron and Steel Co. Ltd. Zhanjiang 524000 China

To investigate the flow of primary slag bearing TiO2 in the cohesive zone of blast furnaces, experiments were carded out based on the laboratory-scale packed bed systems. It is concluded that the initial temperature of slag dripping increases with decreasing FeO content and increasing TiO2 content. The slag holdup decreases when the FeO content is in the range of 5wt%-10wt%, whereas it increases when the FeO content exceeds 10wt% . Meanwhile, the slag holdup decreases when the TiO2 content increases from 5wt% to 10wt% but increases when the TiO2 content exceeds 10wt%. Moreover, slag/coke interface analysis shows that the reaction between FeO and TiO2 occurs be- tween the slag and the coke. The slag/coke interface is divided into three layers： slag layer, iron-rich layer, and coke layer. TiO2 in the slag is reduced by carbon, and the generated Ti diffuses into iron.

关键词： blast furnace slag titanium dioxide packed beds dripping