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Reduction and melting separation mechanism of boron-bearing iron concentrate/coal composite pellet

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Journal of Iron and Steel Research International 2018年第3期25卷 310-319页

作者： Guang Wang qing-guo xue Jing-song Wang State Key Laboratory of Advanced Metallurgy University ofScience and Technology Beijing Beijing 100083 China

Realizing the boron and iron separation through selective reduction and melting separation of boron-bearing iron con- centrate is of great significance for the utilization of crude ludwigite. The reduction and melting separation mechanism of boron-bearing iron concentrate/coal composite pellet was systematically investigated. The reduction and melting separation test of small size pellet was performed to reveal the evolution of slag and iron in the melting separation process. The isothermal reduction experiment showed the relationship between reduction stage and melting separation stage, and the step reduction and melting separation was perfectly achieved. Coal particles existed through the reduction and melting separation process and finally formed brown residue around the separated product. The pellet could not realize melting separation when the B2O3 content in the concentrate was lower than 6.00 wt%.

关键词： Boron-bearing iron concentrate Composite pellet-Reduction Melting separation-Mechanism

Mathematical model of the direct reduction of dust composite pellets containing zinc and iron

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International Journal of Minerals,Metallurgy and Materials 2013年第7期20卷 627-635页

作者： Xiu-wei An Jing-song Wang xue-feng She qing-guo xue State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing School of Mechanical Engineering University of Science and Technology Beijing

Direct reduction of dust composite pellets containing zinc and iron was examined by simulating the conditions of actual production process of a rotary hearth furnace （RHF） in laboratory. A mathematical model was constructed to study the reduction kinetics of iron oxides and ZnO in the dust composite pellets. It was validated by comparing the calculated values with experimental results. The effects of furnace temperature, pellet radius, and pellet porosity on the reduction were investigated by the model. It is shown that furnace temperature has obvious influence on both of the reduction of iron oxides and ZnO, but the influence of pellet radius and porosity is much smaller. Model calculations suggest that both of the reduction of iron oxides and ZnO are under mixed control with interface reactions and Boudouard reaction in the early stage, but only with interface reactions in the later stage.

关键词： rotary hearth furnaces dust zinc ore pellets direct reduction process mathematical models kinetics

Reduction–melting behaviors of boron-bearing iron concentrate/carbon composite pellets with addition of CaO

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International Journal of Minerals,Metallurgy and Materials 2015年第9期22卷 926-932页

作者： Guang Wang qing-guo xue xue-feng She Jing-song Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

Although the total amount of boron resources in China is high, the grades of these resources are low. The authors have already proposed a new comprehensive utilization process of boron-bearing iron concentrate based on the iron nugget process. The present work describes a further optimization of the conditions used in the previous study. The effects of CaO on the reduction-melting behavior and properties of the boron-rich slag are presented. CaO improved the reduction of boron-bearing iron concentrate/carbon composite pellets when its content was less than lwt%. Melting separation of the composite pellets became difficult with the CaO content increased. The sulfur content of the iron nugget gradually decreased from 0.16wt% to 0.046wt% as the CaO content of the pellets increased from 1wt% to 5wt%. CaO negatively affected the iron yield and boron extraction efficiency of the boron-rich slag. The mineral phase evolution of the boron-rich slag during the reduction-melting separation of the composite pellets with added CaO was also deduced.

关键词： iron concentrate boron ore reduction composite pellets calcium oxide

Gasification kinetics of char formed from waste polyvinyl chloride for efficient utilization in ironmaking process

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Journal of Iron and Steel Research International 2022年第10期29卷 1535-1544页

作者： Guang Wang Hong-qiang Zhang Jing-song Wang qing-guo xue State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China

In the prevailing incineration processes of municipal solid waste,the presence of polyvinyl chloride(PVC)may cause environmental *** energy-intensive ironmaking sector in the iron and steel industry operates at high temperature and under high reduction potential with the function of energy conversion,which can provide a potential path for the collaborative utilization of waste plastics in large quantities and low *** gasification of the char formed from PVC when processed in the ironmaking sector is significant for the development of the related ***,the gasification experiment of PVC char and traditional carbonaceous materials was performed by thermogravimetric *** results indicated that the gasification ability decreased in the sequence of PVC char>anthracite coal>coke>***,kinetics were also analyzed by Coats-Redfern and Doyle *** PVC char showed the best gasification ability with the smallest activation energy,ranging from 87.18 to 117.52 kJ/mol,and the smaller graphitization degree of PVC char compared with other carbonaceous materials should be the main reason for its excellent gasification reactivity.

关键词： Polyvinyl chloride(PVC) Thermochemical conversion Ironmaking Char Gasification

Effect of carbon species on the reduction and melting behavior of boron-bearing iron concentrate/carbon composite pellets

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 522-528页

作者： Guang Wang Yin-gui Ding Jing-song Wang xue-feng She qing-guo xue State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

Iron nugget and boron-rich slag can be obtained in a short time through high-temperature reduction of boron- bearing iron concentrate by carbonaceous material, both of which are agglomerated together as a carbon composite pellet. This is a novel flow sheet for the comprehensive utilization of boron-bearing iron concentrate to produce a new kind of man-made boron ore. The effect of reducing agent species （i.e., carbon species） on the reduction and melting process of the composite pellet was investigated at a laboratory scale in the present work. The results show that, the reduction rate of the composite pellet increases from bituminite, anthracite, to coke at temperatures ranging from 950 to 1300~C. Reduction temperature has an important effect on the microstructure of reduced pellets. Carbon species also affects the behavior of reduced metallic iron particles. The anthracite-bearing composite pellet melts faster than the bituminite- bearing composite pellet, and the coke-bearing composite pellet cannot melt due to the high fusion point of coke ash. With anthracite as the reducing agent, the recovery rates of iron and boron are 96.5% and 95.7%, respectively. This work can help us get a further understanding of the new process mechanism.

关键词： iron ore pellets iron ore reduction boron bituminite anthracite coke

Preparation of CaO-containing carbon pellets from coking coal and calcium oxide:Effects of temperature,pore distribution and carbon structure on compressive strength in pyrolysis furnace

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International Journal of Minerals,Metallurgy and Materials 2021年第7期28卷 1153-1163页

作者： Xiao-min You xue-feng She Jing-song Wang qing-guo xue Ze-yi Jiang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083China

CaO-containing carbon pellets(CCCP)were successfully prepared from well-mixed coking coal(CC)and calcium oxide(CaO)and roasted at different pyrolysis *** effects of temperature,pore distribution,and carbon structure on the compressive strength of CCCP was investigated in a pyrolysis furnace(350-750℃).The results showed that as the roasting temperature increased,the compressive strength also increased and furthermore,structural defects and imperfections in the carbon crystallites were gradually eliminated to form more organized char structures,thus forming high-ordered ***,the CCCP preheated at 750℃exhibited the highest compressive strength.A positive relationship between the compressive strength and pore-size homogeneity was established.A linear relationship between the com-pressive strength of the CCCP and the average stack height of CC was ***,a four-stage caking mechanism was developed.

关键词： calcium oxide-containing carbon pellets calcium carbide coking coal compressive strength pyrolysis furnace

Numerical analysis of carbon saving potential in a top gas recycling oxygen blast furnace

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Journal of Iron and Steel Research International 2017年第6期24卷 608-616页

作者： xue-feng She Xiu-wei An Jing-song Wang qing-guo xue Ling-tan Kong State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Beijing 100083 China qingdao Special Steel Company Limited Shandong Qingdao 266409 Shandong China

Aiming at the current characteristics of blast furnace （BF） process, carbon saving potential of blast furnace was investigated from the perspective of the relationship between degree of direct reduction and carbon consumption. A new relationship chart between carbon consumption and degree of direct reduction, which can reflect more real situation of blast furnace operation, was established. Further- more, the carbon saving potential of hydrogen-rich oxygen blast furnace （OBF） process was ana- lyzed. Then, the policy implications based on this relationship chart established were suggested. On this basis, the method of improving the carbon saving potential of blast furnace was recycling the top gas with removal of CO2 and H2O or increasing hydrogen in BF gas and full oxygen blast. The results show that the carbon saving potential in traditional blast furnace （TBF） is only 38 56 kg · t ^-1 while that in OBF is 138 kg · t ^-1. Theoretically, the lowest carbon consumpt!on of OBF is 261 kg · t ^-1 and the corresponding degree of direct reduction is 0.04. In addition, the theoretical lowest carbon consumption of hydrogen-rich OBF is 257 kg · t ^-1. The modeling analysis can be used to estimate the carbon savings potential in new ironmaking process and its related CO2 emissions.

关键词： Blast furnace processDirect reduction degreeCarbon consumptionDirect reductionCarbon saving potentiaOxygen blast furnace

Exploring a new path of green and efficient utilization of sinter return fine to produce composite pellets

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Journal of Iron and Steel Research International 2024年第7期31卷 1610-1622页

作者： Yan-biao Chen Wen-guo Liu Hao guo Jing-song Wang qing-guo xue Hai-bin Zuo State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China MCC Capital Engineering and Research Incorporation Limited Beijing 100176China

Efficient utilization of sinter return fine is an important measure to reduce cost,increase efficiency,save energy and reduce emission.A new path of green and efficient utilization of return fine was proposed to produce composite *** metallurgical properties of composite pellets under the condition of hydrogen-rich blast furnace were *** experimental results indicate that the coated concentrate was consolidated for the composite pellets through normal Fe_(2)O_(3) *** the surface of core return fine,the liquid phase formed due to its low-melting point,assimilated the adjacent concentrate,and then consolidated with the temperature *** with regular pellets,the com-pressive strength and reduction swelling index of composite pellets were decreased,but the reducibility index and softening-melting properties were *** addition,the reduction degradation index of composite pellets was sig-nificantly higher than that of ***,adding composite pellets was conducive to indirect reduction in blast furnace,reducing fuel ratio and improving production *** to the effect of the roasting system on the metallurgical properties,the roasting temperature and time were determined as 1250℃and 30 min,*** composite pellets can be produced under the traditional pelletizing process.

关键词： Sinter Return fine Composite pellet Roasting system Metallurgical property Hydrogen-rich blast furnace

Carbothermic reduction behaviors of Ti–Nb-bearing Fe concentrate from Bayan Obo ore in China

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International Journal of Minerals,Metallurgy and Materials 2018年第1期25卷 28-36页

作者： Guang Wang Ya-xing Du Jing-song Wang qing-guo xue State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

To support the development of technology to utilize low-grade Ti-Nb-bearing Fe concentrate, the reduction of the concentrate by coal was systematically investigated in the present paper. A liquid phase formed when the Ti Nb-bearing Fe concentrate/coal composite pel- let was reduced at temperatures greater than 1100℃. The addition of CaCO3 improved the reduction rate when the slag basicity was less than 1.0 and inhibited the formation of the liquid phase. Mechanical milling obviously increased the metallization degree compared with that of the standard pellet when reduced under the same conditions. Evolution of the mineral phase composition and microstructure of the reduced Ti-Nb-bearing Fe concentrate/coal composite pellet at 1100~C were analyzed by X-ray diffraction and scanning electron microsco- py-energy-dispersive spectroscopy. The volume shrinkage value of the reduced Ti-Nb-bearing Fe concentrate/coal composite pellet with a basicity of 1.0 was approximately 35.2% when the pellet was reduced at 1100℃ for 20 min, which enhanced the external heat transfer to the lower layers when reduced in a practical rotary hearth furnace. The present work provides key parameters and mechanism understanding for the development of carbothermic reduction technology of a Ti-Nb-bearing Fe concentrate incorporated in a pyrometallurgical utilization flow sheet.

关键词： Ti-Nb bearing iron concentrate carbothermic reduction basicity mechanical milling volume shrinkage