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Upgrading and dephosphorization of Western Australian iron ore using reduction roasting by adding sodium carbonate

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International Journal of Minerals,Metallurgy and Materials 2013年第6期20卷 505-513页

作者： De-qing Zhu Tie-jun Chun Jian Pan Li-ming Lu Zhen He School of Minerals Processing and Bioengineering Central South University Commonwealth Scientific and Industrial Research Organisation (CSIRO)

The technology of direct reduction by adding sodium carbonate （Na2CO3） and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated by optical microscopy and scanning electron microscopy. It is found that phosphorus exists within limonite in the form of solid solution, which cannot be removed through traditional ways. During reduction roasting, Na2CO3 reacts with gangue minerals （SiO2 and A1203）, forming aluminum silicate-containing phosphorus and damaging the ore structure, which promotes the separation between iron and phosphorus during magnetic separation. Meanwhile, Na2CO3 also improves the growth of iron grains, increasing the iron grade and iron recovery. The iron concentrate, assaying 94.12wt% Fe and 0.07wt% P at the iron recovery of 96.83% and the dephosphorization rate of 74.08%, is obtained under the optimum conditions. The final product （metal iron powder） after briquetting can be used as the burden for steelmaking by an alactrie *** furnace to rer）la,ce scrar） steel.

关键词： iron ore reduction sodium carbonate ore roasting magnetic separation phosphorus removal

Dynamic Research of iron ore reduction

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Dynamic Research of Iron Ore Reduction

Fluidization behavior and reducibility of iron ore fines during hydrogen-induced fluidized bed reduction

2012年全国冶金物理化学学术会议

作者：林银河郭占成唐惠庆王其洪任山李京伟 State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

Micro-fluidized bed reactor is a new research method for the reduction of iron ore *** reactor was operated as a differential reactor to ensure a constant gas concentration and temperature within the reactor *** order to understand the dynamic process of the reaction reduction,micro-fluidized bed was used to do a series of kinetic *** tests showed that the rate-determining step of micro-fluidized bed was the surface chemistry reaction of particles.

关键词： iron ore reduction micro-fluidized bed rate-determining step degree of reduction reduction time

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Particuology 2020年第5期18卷 36-46页

作者： Daniel Spreitzer Johannes Schenk Chair of Ferrous Metallurgy Montanuniversitaet LeobenFranz-Josef-Straβe 188700 LeobenAustria

A laboratory fluidized bed reactor was used to investigate the fluidization behavior and reducibility of various iron ore *** was chosen as a reducing agent across a temperature range of 873-1073 *** magnetite ore used exhibited strong sticking behavior after the initiation of metallic iron *** other tested ores fluidized sufficiently well when subjected to the same high reduction *** kinetic analysis was conducted using a previously developed model to include three rate-limiting step *** trend of apparent activation energy was correlated with the degree of ***,the influence of varying the specific gas rate was *** results show the variation in reducibility as a result of different interactions,which influence the rate-limiting mechanisms of nucleation and the undertaken chemical reactions,which vary as a function of temperature and degree of *** apparent activation energies,determined from the reduction of wtistite to metallic iron,were in the range of 15-60 kJ/mol,depending on the iron ore used and the degree of *** change in apparent activation energy deriving from the increased specific gas rate can be explained by an increasing nucleation effect,especially at lower reduction temperatures.

关键词： Fluidized bed iron ore reduction Hydrogen Fluidization behavior Kinetic analysis

Formation and characterization of metallic iron grains in coal-based reduction of oolitic iron ore

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International Journal of Minerals,Metallurgy and Materials 2017年第2期24卷 123-129页

作者： Yong-sheng Sun Yue-xin Han Yan-feng Li Yan-jun Li School of Resources and Civil Engineering Northeastern University Shenyang 110819 China

To reveal the formation and characteristics of metallic iron grains in coal-based reduction, oolitic iron ore was isothermally re- duced in various reduction times at various reduction temperatures. The microstructure and size of the metallic iron phase were investigated by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and a Bgrimm process mineralogy analyzer. In the results, the re- duced Fe separates from the ore and forms metallic iron protuberances, and then the subsequent reduced Fe diffuses to the protuberances and grows into metallic iron grains. Most of the metallic iron grains exist in the quasi-spherical shape and inlaid in the slag matrix. The cumula- tive frequency of metallic iron grain size is markedly influenced by both reduction time and temperature. With increasing reduction temperature and time, the grain size of metallic iron obviously increases. According to the classical grain growth equation, the growth kinetic parameters, i.e., time exponent, growth activation energy, and pre-exponential constant, are estimated to be 1.3759 ± 0.0374, 103.18 kJ·mol^-1, and 922.05, respec- tively. Using these calculated parameters, a growth model is established to describe the growth behavior of metallic iron grains.

关键词： iron ore reduction metallic iron grain size growth kinetics activation energy

Kinetic studies on the reduction of iron ore nuggets by devolatilization of lean-grade coal

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International Journal of Minerals,Metallurgy and Materials 2016年第12期23卷 1360-1368页

作者： Chanchal Biswas Prithviraj Gupta Arnab De Mahua Ghosh Chaudhuri Rajib Dey Department Metallurgical and Material Engineering Jadavpur University Department of Metallurgy and Materials Engineering Indian Institute of EngineeringScience & Technology School of Materials Science and Nano Technology Jadavpur University

An isothermal kinetic study of a novel technique for reducing agglomerated iron ore by volatiles released by pyrolysis of lean-grade non-coking coal was carried out at temperature from 1050 to 1200℃ for 10-120 min. The reduced samples were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, and chemical analysis. A good degree of metallization and reduction was achieved. Gas diffusion through the solid was identified as the reaction-rate-controlling resistance; however, during the initial period, particularly at lower temperatures, resistance to interfacial chemical reaction was also significant, though not dominant. The apparent rate constant was observed to increase marginally with decreasing size of the particles constituting the nuggets. The apparent activation energy of reduction was estimated to be in the range from 49.640 to 51.220 kJ/mol and was not observed to be affected by the particle size. The sulfur and carbon contents in the reduced samples were also determined.

关键词： iron ore reduction coal devolatilization kinetic studies

Recovery of iron from high phosphorus oolitic iron ore using coal-based reduction followed by magnetic separation

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International Journal of Minerals,Metallurgy and Materials 2013年第5期20卷 411-419页

作者： Yong-sheng Sun Yue-xin Han Peng Gao Ze-hong Wang Duo-zhen Ren College of Resources and Civil Engineering Northeastern University

Oolitic iron ore is one of the most important iron resources. This paper reports the recovery of iron from high phosphorus oolitic iron ore using coal-based reduction and magnetic separation. The influences of reduction temperature, reduction time, C/O mole ratio, and CaO content on the metallization degree and iron recovery were investigated in detail. Experimental results show that reduced products with the metallization degree of 95.82% could be produced under the optimal conditions （i.e., reduction temperature, 1250℃; reduction time, 50 min; C/O mole ratio, 2.0; and CaO content, 10wt%）. The magnetic concentrate containing 89.63wt% Fe with the iron recovery of 96.21% was obtained. According to the mineralogical and morphologic analysis, the iron minerals had been reduced and iron was mainly enriched into the metallic iron phase embedded in the slag matrix in the form of spherical particles. Apatite was also reduced to phosphorus, which partially migrated into the metallic iron phase.

关键词： oolitic iron ore iron ore reduction magnetic separation phosphorus

reduction Behavior With CO Under Micro-Fluidized Bed Conditions

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Journal of iron and Steel Research International 2013年第2期20卷 8-13页

作者： LIN Yin-he GUO Zhan-cheng TANG Hui-qing State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing

To process optimization and improve the degree of reduction, a two-step experiment was designed. The experiment was carried out in the micro-fluidized bed. The reactor in the micro-fluidized bed is operated as a differential reactor to ensure an equal temperature and residence time with the reactor volume. The experiment used Brazilian iron ore and reducing gas of CO. The operating temperature was 400 to 800 ℃ and the residence time was between 10 and 60 min. In correspondence with experiment, microscopic technique was applied too. The test shows that temperature and residence time of the pre-reduction stage have an important effect on the degree of reduction. By using two-step experiment, the maximum value of reduction degree increases by 44.1% compared with the maximum value of traditional reduction experiment. Microscopic analysis shows that the specific surface area, surface morphology and texture of reduced iron ore after pre-reduction stage have an important effect on the degree of final reduction too.

关键词： iron ore reduction two-step experiment specific suriace area morphology pre-reduction degree finalreduction degree

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

Correlation between aggregation structure and tailing mineral crystallinity

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International Journal of Minerals,Metallurgy and Materials 2014年第9期21卷 845-850页

作者： Wen-tao Hu Xin-wei Li Hua-jun Wang Chuan-yao Sun Xu-qin Duan State Key Laboratory of the Ministry of Education of China for High-Efficient Mining and Safety of Metal Mines University of Science and Technology Beijing School of Civil and Environmental Engineering University of Science and Technology Beijing State Key Laboratory of Mineral Processing Science and Technology Beijing General Research Institute of Mining and Metallurgy

Direct reduction is an emerging technology for the utilization of refractory iron ore. With this technology, iron oxides in the ore can be reduced to recoverable elemental iron. The structure of granular aggregates in direct reduction products was investigated by X-ray diffraction （XRD）. The results show that iron is mainly generated as a shell in the outer edge of the aggregates. The thermal conductivity of the iron shell is higher than that of other minerals. Thus, minerals close to the iron shell cool faster than those in the inner shells and do not crystallize well. These minerals mainly become stage 2 tailings. Hence the XRD intensity of stage 2 tailings is lower than that of stage 1 tailhags. When iron is mainly generated in the interior of the aggregates, the crystallinity of stage 2 tailings will be higher than that of stage 1 tailings. This indicates that the crystallinity of tailings can be used as a marker for the aggregate structure.

关键词： iron ore reduction aggregation crystallinity railings