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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

Carbothermic reduction characteristics of ludwigite and boron–iron magnetic separation

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International Journal of Minerals,Metallurgy and Materials 2018年第9期25卷 1000-1009页

作者： Guang wang Qing-guo Xue jing-song wang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

Ludwigite is a kind of complex iron ore containing boron, iron, and magnesium, and it is the most promising boron resource in China. Selective reduction of iron oxide is the key step for the comprehensive utilization of ludwigite. In the present work, the reduction mechanism of ludwigite was investigated. The thermogravimetry and differential scanning calorimetry analysis and isothermal reduction of ludwigite/coal composite pellet were performed. Ludwigite yielded a lower reduction starting temperature and a higher final reduction degree compared with the traditional iron concentrates. Higher specific surface area and more fine cracks might be the main reasons for the better reducibility of ludwigite. Reducing temperature highly affected the reaction fraction and microstructure of the reduced pellets, which are closely related to the separation degree of boron and iron. Increasing reducing temperature benefited the boron and iron magnetic separation. Optimum magnetic separation results could be obtained when the pellet was reduced at 1300°C. The separated boron-rich non-magnetic concentrate presented poor crystalline structure, and its extraction efficiency for boron reached 64.3%. The obtained experimental results can provide reference for the determination of the comprehensive utilization flow sheet of ludwigite.

关键词： complex iron ore boron resource carbothermic reduction magnetic separation

Mathematical model of burden distribution in bell-less top blast furnace

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Journal of Iron and Steel Research International 2023年第2期30卷 216-226页

作者： Jian-sheng Chen Hai-bin Zuo jing-xiu wang Qing-guo Xue jing-song wang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing100083China

The burden distribution in the shaft of blast furnace is known to affect the gas distribution,heat transfer,and chemical reactions inside the ***,the internal layer structure of burden in the shaft cannot be directly ***,a mathematical model for evaluating burden profile and layer structure was established.A sensitivity analysis based on the model was implemented to elucidate the effect of some factors on the burden distribution,including the stockline height and the mass of central *** results show that the width of funnel zone widens with the increase in stockline height,and the mass percentage of ore to coke in this zone slightly ***,the mass of central coke shows a significant influence on the width of coke channel,and 2%of batch mass of coke is recommended to implement central coke charging *** model has been indirectly verified by the gas temperature in operating blast furnace and successfully applied to online evaluate burden distribution.

关键词： Blast furnace Burden distribution Mathematical model Stockline height Central coke

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

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

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

Effect of gangue composition on iron nugget production from iron ore-coal composite pellet

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Journal of Iron and Steel Research International 2019年第9期26卷 917-925页

作者： Shi-han Zhang Guang wang Hao Zhang jing-song wang Qing-guo Xue State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China

The rotary hearth furnace iron nugget process has advantages of short reaction time, high-quality reduced product and wide adaptability of raw materials and meets the trend in ecofriendly development of iron and steel industry. Although the rotary hearth furnace iron nugget process cannot replace blast furnace process, which is affected by production scale, thermal efficiency and technical maturity, it is still a feasible technology for iron production. In order to realize the efficient utilization of high Al2O3 iron ore resources, preparation of iron nuggets with high Al2O3 iron ore was studied. Using iron concentrate as raw material, the effects of slag basicity, Al2O3 and MgO on melting separation of iron ore–coal composite pellets, such as the melting separation temperature, the melting separation time, the morphology of melting separated product, and the recovery rate of iron nugget, were studied. The results showed that relatively low or high liquidus temperature of slag had a negative effect on reduction and melting separation of iron ore–coal composite pellets. The increase in fluidity index of slag resulted in a decline in the melting separation temperature and time of iron ore–coal composite pellets. Optimum basicity to produce iron nuggets using iron ore–coal composite pellets was 0.8–1.0, 0.4 and 0.8 for iron concentrate containing 2, 4 and 6–10 wt.% Al2O3, respectively. Corresponding liquidus temperature and fluidity index of slag were 1300–1475 C and above 4.5, respectively. Under this condition, the lowest melting separation temperature and the shortest melting separation time of iron ore–coal composite pellets were 1375 C and 7 min, respectively. The recovery rate of metallic iron in the form of iron nugget could reach about 94%.

关键词： Rotary hearth furnace Iron nugget Basicity Al2O3 Melting separation Composite pellet

Synthesis and bioactivity of N-cyclopropanecarboxyl-N′-pyridin-2-yl thiourea derivatives and related fused ring compounds

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Chinese Chemical Letters 2009年第3期20卷 288-291页

作者： Li Tian Jie song jing wang Bin Liu College of Chemistry and Life Tianjin Normal UniversityTianjin 300387 China

Cyclopropanecarboxylic acid or 2,2-dimethyl cyclopropanecarboxylic acid was used as a leading compound for its biological activity. Six new N-（substituted） cyclopropanecarboxyl-N＇-pyridin-2-yl thioureas were prepared. Compound 5 was obtained by oxidizing cyclization of compound 4 in the presence of bromine in chloroform solution. The structures of 4 and 5 were confirmed by 1H NMR and elemental analysis. The preliminary biological tests indicate that compound 4b and 4e have excellent herbicidal activity, and compound 4e and 4f have excellent fungicidal activity.

关键词： Cyclopropanecarboxylic acid Heterocycle Thiourea Biological activity Pyridine

The mechanism and products for co-thermal extraction of biomass and low-rank coal with NMP

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International Journal of Minerals,Metallurgy and Materials 2019年第12期26卷 1512-1522页

作者： Jun Zhao Hai-bin Zuo jing-song wang Qing-guo Xue State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

The high-value utilization of low-rank coal would allow for expanding energy sources,improving energy efficiencies,and alleviating environmental *** order to use low-rank coal effectively,the hypercoals(HPCs)were co-extracted from two types of low-rank coal and biomass via N-methyl-2-purrolidinone(NMP)under mild *** structures of the HPCs and residues were characterized by proximate and ultimate analysis,Raman spectra,and Fourier transform infrared(FT-IR)*** carbon structure changes within the raw coals and HPCs were *** individual thermal dissolution of Xibu(XB)coal,Guandi(GD)coal,and the biomass demonstrated that the biomass provided the lowest thermal dissolution yield Y1 and the highest thermal soluble yield Y2 at 280℃,and the ash content of three HPCs decreased as the extraction temperature ***-thermal extractions in NMP at various coal/biomass mass ratios were performed,demonstrating a positive synergic effect for Y2 in the whole coal/biomass mass *** maximum value of Y2 was 52.25wt% for XB coal obtained with a XB coal/biomass of 50wt% *** maximum value of Y2 was 50.77wt% for GD coal obtained with a GD coal/biomass of 1:*** difference for the optimal coal/biomass mass ratios between XB and GD coals could be attributed to the different co-extraction mechanisms for this two type coals.

关键词： low-rank coal biomass co-thermal extraction NMP hypercoal