Kinetic of Carbothermal Reduction Reaction of Bismuth Trioxide
Received:September 06, 2023   Revised:September 14, 2023   Accepted:September 18, 2023      Published Online:November 30, 2023
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DOI:doi:10.3969/j.issn.1007-7545.2024.01.004
KeyWord:bismuth trioxide; carbothermal reduction; dynamics; activation energy
              
AuthorInstitution
ZHANG Xinyang 东北大学冶金学院
XING Pengfei 东北大学冶金学院
ZHUANG Yanxin 材料电磁过程研究教育部重点实验室
DU Xinghong 东北大学冶金学院
WANG Shuai 东北大学冶金学院
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Abstract:
      Due to the high density of bismuth element, it is easy to precipitate in the process of carbothermic reduction smelting of industrial silicon, resulting in uneven distribution of impurities in the industrial silicon obtained from smelting, so it is of great significance to study the kinetic behavior of bismuth in the carbothermic reduction reaction and provide theoretical guidance for the control of bismuth in industrial silicon smelting. The effects of different carbon reducing agents on the carbon thermal reduction of bismuth trioxide were studied by thermogravimetric analysis. The results show that petroleum coke as reducing agent has better reducing properties duo to its higher activity than graphite. The phase transition sequence of the reduction products of bismuth trioxide at different temperatures is Bi2O3→intermediate oxide Bi2O2.5→Bi. The kinetics of bismuth trioxide carbothermic reduction reaction at different heating rates was studied by thermogravimetric analysis. The average apparent activation energy of bismuth trioxide carbothermic reduction reaction is 142.41 kJ/mol and the pre-exponential factor is 2.96×109 s-1 by iso-conversion method, Kissinger method and ?atava-?esták method. The reaction mechanism belongs to the phase boundary reaction, and the differential form of the corresponding kinetic equation is 3(1—α)2/3.
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