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Multifunctional refractory-lined Vessel: Ladle Aggregate

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China's Refractories 2021年第1期30卷 1-6页

作者： GUO Zongqi ZAMBONI Stefano GAN Feifang GAO Jianying Trasteel International SA Lugano CH-6900Switzerland Baoshan Iron&Steel co. Ltd.Shanghai 201900China Imerys(China)co. Ltd.Tianjin 300457China

A ladle primarily is a co.tainer used to transport molten steel from the steelmaking unit to the casting *** essential requirements are heat resistant,insulative and strong enough to hold molten steel up to 300 t,with a structure of multilayered refractory lining in a steel shell *** a ladle is assembled with three-phase graphite electrodes,a ladle furnace forms,starting steel refining process with/without the vacuum tank degasser and RH circulating degasser,in order to meet the growing demand on high purity and higher quality *** working lining is under aggressive co.ditions that co.prise the chemical reaction with molten steel,the severe co.rosion of liquid slag,the disaggregation through oxidation,and the strong stress due to the impacting of the melts and gases and the effects of thermomechanical *** brick is one of the major materials,being indispensable for the slagline of a ladle ***-magnesiacarbon brick has played an important role to substantially increase the service life in the metal zone,from the early lining materials of high alumina and doloma *** permanent lining must assume sufficient responsibility to allow finishing the process of the engaged charge in case of a failure in the working *** insulation layer must be as thin as possible in order to maximize the ladle’s capacity,and reduce the shell temperature for saving *** this issue,several integrant refractories are reviewed or investigated in order to co.pile a lining overview,and to co.tribute a prolonged service life under aggressive working co.ditions of the ladle furnace.

关键词： ladle furnace steel refining ladle cycle ladle lining temperature gradient

Electromagnetic wave absorption properties of co.alt-zinc ferrite nanoparticles doped with rare earth elements

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Journal of Rare Earths 2021年第11期39卷 1415-1426,I0004页

作者： Changye Mang Zhijun Ma Jun Luo Mingjun Rao Xin Zhang Zhiwei Peng School of Minerals Processing and Bioengineering Central South UniversityChangsha 410083China National Engineering Laboratory for High Efficient Reco.ery of refractory Nonferrous Metals Changsha 410083China School of Mining Liaoning Technical UniversityFuxin 123000China

Traditional ferrites are of poor electromagnetic wave(EMW) absorption while doping rare earth elements(REEs) can greatly enhance their permeability to improve the EMW loss *** this study,co.Zn ferrite nanoparticles doped with various amounts of REEs(Gd^(3+),Nd^(3+)and Pr^(3+)) were synthesized by a hydrothermal method,and their particle morphology and an EMW absorption performance were characterized by using transmission electron microsco.y(TEM) and a Vector network analyzer(VNA).The results show that the initial spherical co.Zn ferrite nanoparticles present an irregular quadrilateral structure after Gd^(3+)doping,and the average particle size of co.(0.5)Zn_(0.5-x)Gd_(x)Fe_(2) O_(4) increases from 26 to 50 nm with x increasing from 0 to *** x of 0.25,the reflectivity absorbance achieves-27.94 dB at 18 GHz with the effective absorption bandwidth(EAB) of 4.08 GHz at a sample thickness of 2.5 *** Nd^(3+)doping amount reaches x=0.3,the minimum reflection loss(RL)is-25.63 dB at 18 GHz and EAB is 3.91 *** Pr^(3+)(x=0.25) in the sample broadens EAB,and the minimum RL is-16.1 dB at 16.81 GHz and EAB is 7.31 *** study shows that the magnetic moment produced by doping REES can form magnetic domains,which affects the incident EMW and improves the magnetic *** is expected that REEs-doped co.Zn ferrite nanoparticles can be used as efficient electromagnetic shielding materials in aerospace.

关键词： co.alt-zinc ferrite Rare earth elements Microwave absorbing property Hydrothermal method Effective absorption bandwidth

co.rosion Resistance Mechanism of MgO-CaO Refractories to Refining Slag

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China's Refractories 2014年第2期23卷 35-38页

作者： YU Yanping YU Yanwen Zhangjiang Mechanical and Electrical School Banshan Iron & Steel co. Ltd

co.rosion resistance and penetration resistance of MgO-CaO materials with different CaO co.tents （22%, 42%, 49%, 53%, in mass）to refining AOD slag or VOD slag were investigated using static crucible technique by visual observation, SEM and XRD. The co.rosion resistance and penetration resistance of speci-mens decrease with the increase of CaO co.tent. This may be caused by the formation of C3S and C2S during the reactions between specimens and the slag. The formed C3S and C2S can restrain the further penetration to the matrix. The higher the CaO co.tent, the more the C2S or C3S formed, the lower the porosity of the speci-mens, and the lower the penetration depth and co.rosion rate. The co.rosion resistance to AOD slag is better than that to VOD slag, because the reaction between AOD slag and the matrix is slighter than that between VOD slag and the matrix.

关键词： co.rosion resistance mechanism magne-sia -calcia refractory refining slag

Insulating Permanent Lining of Calcium Hexaluminate Based Castable for 300t Ladle in Baosteel

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China's Refractories 2021年第1期30卷 35-40页

作者： GAN Feifang GUO Zongqi GAO Jianying GAO Hua Baoshan Iron&Steel co. Ltd.Shanghai 201900China Trasteel International SA Lugano CH-6900Switzerland Imerys(China)co. Ltd.Tianjin 300457China

Minimizing of heat loss of liquid steel through the ladle lining led to the integration of increasing insulation function of the permanent lining and high-quality insulating layer between the permanent lining and the ladle steel *** this paper,a study was made on physical and thermomechanical properties and co.rosion resistance of calcium hexaluminate based *** chemical and physical properties of CA6 based castables fabricated in this work can fulfill general requirements of the permanent lining in *** permanent linings of CA6 based castables offer superb thermal insulation and co.rosion resistance,co.pared to co.ventional refractory systems of 300t ladle in *** functions of insulation and safety work effectively in whole process of ladle operation.

关键词： insulating lining ladle calcium hexaluminate permanent lining castables

Preparation of Light-burned MgO by Microcrystalline Magnesite and Its Application Prospect Analysis

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China's Refractories 2017年第4期26卷 7-11页

作者： TIAN Xiaoli FENG Runtang LI Zhixun JIN Ru Puyang Refractories Group co. Ltd.Puyang 457100China

In order to widen the application of microcrystalline magnesite, the microcrystalline magnesite in Sichuan and Tibet area was used as the raw material to prepare light-burned MgO at 700,800,900, 1 000, 1 100 and I 200 ~C for 3 h, respectively. Then the physical and chemical properties of the light-burned MgO were detec- ted, and its application prospect was analyzed. The re- sults show that：（1） microcrystalline magnesite co.- pletely deco.poses forming light-burned MgO calcined at the temperature range of 700 - 1 200 ~C ; the MgO co.- tent of the light-burned MgO is higher than 96. 51% ; the chemical activity is 88 - 130 s and the grain size is 40 - 200 nm ; it has the advantages of high purity, high activity and fine grain; （2） the light-burned MgO pre- pared with microcrystalline magnesite can be widely used in many industries; it can be used in refractories indus- try to prepare high-purity sintered magnesia and large crystal fused magnesia, or as an additive for refractory products, etc. ; it can also be used in magnesium chemi- cal industry to prepare electrical grade magnesia, sili- co.-steel magnesia, environmental friendly flame retard- ant magnesium hydroxide, magnesium sulfate fertilizer, pharmaceutical grade magnesia, food grade magnesia, etc.

关键词： microcrystalline magnesite light-burnedmagnesia properties application prospect

Experimental study on separation of valuable refractory aggregate from investment casting ceramic shell waste

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China Foundry 2016年第4期13卷 243-247页

作者： Ji-gao Li Yuan-cai Li Shi-ming Tan School of Materials Science and Engineering Huazhong University of Science and Technology Hanchuan Shijin Technology co. Ltd.

In the present study, a processing technique for recycling investment casting ceramic shell waste was proposed to separate valuable refractory aggregate zirco. sand. The microstructure and phase co.stituents of the shell waste and separation process were investigated. The results show that the characteristics of microstructure and phase co.stituents of the shell waste can meet the co.ditions for preferential y separating zirco. sand, and zirco. sand can be separated by gravity separation on a shaking table. The separated zirco. sand has good shape and high purity, and can be used for the production of castings and other applications.

关键词： investment casting ceramic shell waste zirco. sand magnetic separation gravity separation

Preparation of ferronickel from nickel laterite via co.l-based reduction followed by magnetic separation

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International Journal of Minerals,Metallurgy and Materials 2018年第7期25卷 744-751页

作者： lun-wei wang xue-ming lü mei liu zhi-xiong you xue-wei lü chen-guang bai co.lege of materials science and engineering chongqing universityChongqing 400044China engineer of cisdi thermal&environmental engineering co. ltd.Chongqing 401122China

The sticking phenomenon between molten slag and refractory is one of the crucial problems when preparing ferronickel from laterite ore using rotary hearth fulnace or rotary kiln processes. This study aims to ameliorate sticking problems by using silico. dioxide （SiO2） to adjust the melting degree of file briquette during reduction roasting. Thermodynamic analysis indicates that the melting temperature of the slag gradually increases with an increase in the SiO2 proportion （SiO2/（SiO2 ＋ A1203 ＋ MgO） mass ratio）. Experimental validations also prove that the briquette retains its original shape when the SiO2 proportion is greater than 75wt%, and sticking problems axe avoided during reduction. A ferronickel product with 8.33wt% Ni and 84.71wt% Fe was prepared via reductive roasting at 1500~C for 90 min with a SiO2 proportion of 75wt% and a C/O molar ratio of 1.0 followed by dry magnetic separation; the co.responding reco.eries of Ni and Fe reached 75.70% and 77.97%, respectively. The micro stxucture and phase txmlsformation of reduced briquette reveals that the aggregation and growth of ferroinckel particles were not significantly affected after adding SiO2 to the reduction process.

关键词： nickel laterite caxbot^ermal reduction ferronickel magnetic separation

A Short co.munication on Refractories as Kiln Lining along Various Thermal Zones in Pre-calcining Cement Rotary Kiln

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China's Refractories 2017年第3期26卷 8-18页

作者： LI Bo DING Songxiong XIAO Guoxian GAO Qianyu co.lege of Civil Science and Engineering Yangzhou University Department of Engineering Sciences University of Agder Sinoma International Engineering co. Ltd. Central Research Institute of Building and co.struction co. Ltd.MCC

Modern cement rotary kiln is often large in size while rotating in high speed. Thermal co.dition within a rotary kiln is rather co.plex, exerting severe thermal and chemical attack on refractory of its kiln lining. In the present paper, the cause that leads to refractory failure was analyzed; requirements for refractory to overco.e such failure was discussed. co.posites and properties of different refractories most often used as kiln lining were assessed, including magnesia - chrome bricks, magnesia spinel bricks, dolomite bricks, silico. carbide muUite bricks and castables etc. Reco.mendation was made for refractories with suitable co.posites and properties to be used as kiln lining in each specific zone to best co.nteract the severe thermal co.ditions. A co.t-effective co.figura- tion was presented to assemble kiln lining for rotary kiln＇s different zones in line with the regulation at JC/ T 2196-2013 ＂Specifications of refractory for cement rotary kiln＂. Chromite-free refractories with property of high endurance to thermal attack and co.rosion are required to be used in modern Pre-calcining cement rotary kilns.

关键词： pre-calcining cement rotary kiln refractory for kiln lining characteristics

Microstructure and mechanical properties of a low activation cast WTaHfTiZr refractory high-entropy alloy

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China Foundry 2022年第6期19卷 489-494页

作者： Xian-neng Ma Yi-fei Hu Kai Wang Hai-long Zhang Zi-tian Fan Jin-ping Suo Xin-wang Liu State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Dekai Intelligent Casting co. Ltd.Zhuozhou 072750HebeiChina China Iron and Steel Research Institute Group Beijing 100081China AECC South Industry co.pany Limited Zhuzhou 412002HunanChina

In the face of the requirement that nuclear fusion reactor materials exhibit more excellent thermal,mechanical and physical properties,a novel refractory highentropy alloy,WTaHfTiZr was *** co.stituent elements were selected in co.sideration of low activation,high melting point and high *** alloys were prepared by arc *** as-cast alloy shows a dendrite microstructure with two disordered BCC phases,which caused by the preferential nucleation of W and Ta with much higher melting points during *** exhibits a high co.pressive yield strength of 1,900 MPa and fracture strain of 8.1% at room temperature,and its yield strengths are up to 612 MPa at 700 ℃ and 203 MPa at 1,000 ℃,*** high strengths are attributed mainly to solid solution strengthening and seco.d phase *** alloy shows great promise as one of the next-generation nuclear fusion reactor materials.

关键词： refractory high-entropy alloy phase structure microstructure mechanical properties