Growth behavior of the magnetite phase in the reduction of hematite via a fluidized bed
来源期刊：International Journal of Minerals Metallurgy and Materials2019年第10期
论文作者：Jian-wen Yu Yue-xin Han Yan-jun Li Peng Gao
文章页码：1231 - 1238
摘 要：To understand the formation and growth mechanism of the magnetite phase during the fluidized reduction of hematite, a high-purity hematite ore was isothermally reduced using a 20 vol% CO-80 vol% CO2 gas mixture in a micro-fluidized bed to examine the process of the selective conversion of hematite to magnetite. The micro-structural characteristics of the magnetite phase were investigated using scanning electron microscopy（SEM） and the Brunauer, Emmett, and Teller（BET） method, and the thickness of the magnetite layer was measured and evaluated using statistical analysis. The experimental results showed that the fresh magnetite nuclei were dense needles of different lengths, and the original hematite grains became porous after complete reduction to the magnetite phase. The thickness of the magnetite layer increased with an increase in reduction temperature and reduction time. The growth kinetics of the magnetite layer was investigated, and the value of the activation energy E was estimated to be 28.33 kJ/mol.
Jian-wen Yu1,2，Yue-xin Han1，Yan-jun Li1，Peng Gao1
1. School of Resources and Civil Engineering, Northeastern University2. State Key Laboratory of Mineral Processing, Beijing General Research Institute of Mining & Metallurgy Group
摘 要：To understand the formation and growth mechanism of the magnetite phase during the fluidized reduction of hematite, a high-purity hematite ore was isothermally reduced using a 20 vol% CO-80 vol% CO2 gas mixture in a micro-fluidized bed to examine the process of the selective conversion of hematite to magnetite. The micro-structural characteristics of the magnetite phase were investigated using scanning electron microscopy（SEM） and the Brunauer, Emmett, and Teller（BET） method, and the thickness of the magnetite layer was measured and evaluated using statistical analysis. The experimental results showed that the fresh magnetite nuclei were dense needles of different lengths, and the original hematite grains became porous after complete reduction to the magnetite phase. The thickness of the magnetite layer increased with an increase in reduction temperature and reduction time. The growth kinetics of the magnetite layer was investigated, and the value of the activation energy E was estimated to be 28.33 kJ/mol.
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