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Journal of Central South University 2022年第1期29卷 296-312页

作者： LI Nan WANG Feng PAN Liang-ming School of Energy and Power Engineering Chongqing UniversityChongqing 400044China Key Laboratory of Low-grade Energy Utilization Technologies and Systems of Ministry of Education Chongqing 400044China

In this study,innovative ellipsoid pellet with craters on its surface was designed,and the direct reduction process was compared with ellipsoid(without craters)and sphere *** addition,furnace temperature and uneven heat flux density effects on the pellet direct reduction process were also *** results show that ellipsoid pellet is better than that of spherical pellet on metallization ***,under the condition of non-uniform heat flow,the ellipsoid pellet final metallization rate and zinc removal rate were *** the heat transfer effect of ellipsoid pellet with craters was not improved significantly,the metallization rate and zinc removal rate were found improved,which will have a cumulative effect on the pellets direct reduction process in rotary hearth *** varying furnace temperature conditions,the pellet temperature was higher than that of the constant furnace *** 1200 s,pellet Fe concentration increased to 123.6%,metallization rate and zinc removal rate increased to 113.7%and 102.2%,*** results can provide references for the carbon-containing pellet design used in rotary hearth furnace.

关键词： rotary hearth furnaces carbon containing pellets direct reduction process heat and mass transfer mathematical model

Mathematical simulation of direct reduction process in zinc-bearing pellets

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International Journal of Minerals,Metallurgy and Materials 2013年第11期20卷 1042-1049页

作者： Ying Liu Fu-yong Su Zhi Wen Zhi Li Hai-quan Yong Xiao-hong Feng School of Mechanical Engineering University of Science and Technology Beijing CISDI Industrial Furnace Co.Ltd.

A one-dimensional unsteady mathematical model was established to describe direct reduction in a composite pellet made of metallurgical dust. The model considered heat transfer, mass transfer, and chemical reactions including iron oxide reductions, zinc oxide reduction and carbon gasification, and it was numerically solved by the tridiagonal matrix algorithm （TDMA）. In order to verify the model, an experiment was performed, in which the profiles of temperature and zinc removal rate were measured during the reduction process. Results calculated by the mathematical model were in fairly good agreement with experimental data. Finally, the effects of furnace temperature, pellet size, and carbon content were investigated by model calculations. It is found that the pellet temperature curve can be divided into four parts according to heating rate. Also, the zinc removal rate increases with the increase of furnace temperature and the decrease of pellet size, and carbon content in the pellet has little influence on the zinc removal rate.

关键词： metallurgical dust ore pellets direct reduction process mathematical models

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

Numerical simulation of the direct reduction of pellets in a rotary hearth furnace for zinc-containing metallurgical dust treatment

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International Journal of Minerals,Metallurgy and Materials 2013年第7期20卷 636-644页

作者： Yu-liang Wu Ze-yi Jiang Xin-xin Zhang Peng Wang Xue-feng She School of Mechanical Engineering University of Science and Technology Beijing Beijing Engineering Research Center for Energy Saving and Environmental Protection University of Science and Technology Beijing Beijing Key Laboratory for Energy Saving and Emission reduction of Metallurgical Industry University of Science and Technology Beijing

A mathematical model was established to describe the direct reduction of pellets in a rotary hearth furnace （RHF）. In the model, heat transfer, mass transfer, and gas-solid chemical reactions were taken into account. The behaviors of iron metallization and dezincification were analyzed by the numerical method, which was validated by experimental data of the direct reduction of pellets in a Si-Mo furnace. The simulation results show that if the production targets of iron metallization and dezincification are up to 80% and 90%, respectively, the furnace temperature for high-temperature sections must be set higher than 1300~ C. Moreover, an undersupply of secondary air by 20% will lead to a decline in iron metallization rate of discharged pellets by 10% and a decrease in dezincing rate by 13%. In addition, if the residence time of pellets in the furnace is over 20 min, its further extension will hardly lead to an obvious increase in production indexes under the same furnace temperature curve.

关键词： rotary hearth furnaces direct reduction process dust ore pellets dezincification numerical methods

reduction and melting behavior of carbon composite lateritic bauxite pellets

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International Journal of Minerals,Metallurgy and Materials 2015年第4期22卷 381-388页

作者： Ying-yi Zhang Jie Zhao Yuan-hong Qi Xiang-li Cheng Zong-shu Zou State Key Laboratory of Advance Steel processes and Products Central Iron and Steel Research Institute School of Material and Metallurgy Northeast University

direct reduction of low-grade lateritic bauxite was studied at high temperature to recover Fe and beneficiate AlzO3 slag. The re- sults show that a metallization rate of 97.9% and a nugget recovery rate of 85.1% can be achieved when the reducing and melting tempera- tures are 1350 and 1480℃, respectively. Moreover, a higher-grade calcium aluminate slag （A1203 = 50.52wt%） can also be obtained, which is mainly composed of ct-A1203, hercynite （FeAI：O4）, and gehlenite （Ca2A12SiO7）. In addition, high-quality iron nuggets have been produced from low-grade lateritic bauxite. The nugget is mainly composed of iron （93.82wt%） and carbon （3.86wt%）, with almost no gangue （slag）.

关键词： bauxite ore pellets direct reduction process melting behavior metallization

Basic properties of steel plant dust and technological properties of direct reduction

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International Journal of Minerals,Metallurgy and Materials 2011年第3期18卷 277-284页

作者： Xue-feng She Jing-song Wang Qing-guo Xue Yin-gui Ding Sheng-sheng Zhang Jie-ji Dong Hui Zeng School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Beijing 100083 China Shandong Laiwu Iron and Steel Co. Ltd. Laiwu 271104 China

Basic physicochemical properties of the dust from Laiwu Iron and Steel Co. Ltd. were studied. It is found that C, Zn, K, Na, etc. exist in the fabric filter dust, off gas （OG） sludge, fine ash in converter, and electrical field dust in sinter. Among these, OG sludge gives the finest particle, more than 90% of which is less than 2.51 mm. The dust can lead to a serious negative influence on the production of sintering and blast furnaces （BF） if it is recycled in sintering. The briquette and reduction experimental results showed that the qualified strength could be obtained in the case of 8wt% molasses or 4wt% QT-10 added as binders. Also, more than 75% of metallization ratio, more than 95% of dezincing ratio, as well as more than 80% of K and Na removal rates were achieved for the briquettes kept at 1250℃ for 15 min during the direct reduction process. SEM observation indicated that the rates of indirect reduction and carbonization became dominating when the bri-quettes were kept at 1250℃ for 6 min.

关键词： steel metallurgy dust zinc direct reduction process briquettes

direct reduction of iron ore by biomass char

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 514-521页

作者： Hai-bin Zuo Zheng-wen Hu Jian-liang Zhang Jing Li Zheng-jian Liu State Key Laboratory of Advenced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

By using thermogravimetric analysis the process and mechanism of iron ore reduced by biomass char were investigated and compared with those reduced by coal and coke. It is found that biomass char has a higher reactivity. The increase of carbon-to-oxygen mole ratio （C/O） can lead to the enhancement of reaction rate and reduction fraction, but cannot change the temperature and trend of each reaction. The reaction temperature of hematite reduced by biomass char is at least 100 K lower than that reduced by coal and coke, the maximum reaction rate is 1.57 times as high as that of coal, and the final reaction fraction is much higher. Model calculation indicates that the use of burden composed of biomass char and iron ore for blast furnaces can probably decrease the temperature of the thermal reserve zone and reduce the CO equilibrium concentration.

关键词： ironmaking biomass char hematite direct reduction process thermogravimetric analysis

Abstracts from Journal of University of Science and Technology Beijing (in Chinese)

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International Journal of Minerals,Metallurgy and Materials 2012年第7期19卷 668-668页

direct reduction-leaching process for high ferric bauxite Wen-tao Hu, Hua-jun Wang, Chuan-yao Sun, Guang-kai Tong, Chun-ling Ji, and Cui-ling Wang Abstract： A direct reduction method was proposed which uses soda ash as the flux and coal as the reductant. By using this method hematite is reduced to iron, which can be recovered by magnetic separation, while A1203 is translated into sodium aluminate, which can be recovered from the solution. The effects of reduction temperature, reduction time, Na2CO3 dosage and reductant dosage on the grade of iron powder, the recovery of iron powder and the recovery of alumina were investigated on the basis of the single factor alteration principle. The process and reaction mechanism were studied by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and energy dispersive spectrometry （EDS）. Orthogonal experiments were designed for optimiz- ing the experimental parameters.

关键词： bauxite iron alumina direct reduction process leaching