Mechanism of Aluminothermic Reduction of MgO
Mechanism of Aluminothermic Reduction of MgO
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DOI：
10.2355/tetsutohagane1955.92.4_239
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发表时间：
2006-04
影响因子：
0.3
通讯作者：
Jian Yang;M. Kuwabara;Zhongzhu Liu;T. Asano;M. Sano
中科院分区：
文献类型：
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作者：
Jian Yang;M. Kuwabara;Zhongzhu Liu;T. Asano;M. Sano
摘要：研究了利用氧化镁铝热还原原位生成的镁蒸气对铁水进行脱硫脱氧的方法。本文探讨了用氧化镁和铝粉组成的球团对氧化镁进行铝热还原的机理。对球团在不同温度下不同还原阶段的SEM观察表明，1473K以上会刺激铝颗粒上氧化铝膜的断裂和消失，从而大大加速氧化镁的还原。利用高温光学显微镜（HTOM）对氧化镁的铝热还原过程进行了现场观察，发现该还原过程是在铝液渗透到氧化镁相后进行的。侵彻从1273K开始，在1373K以上加速。在1473K发生剧烈的降低。对冷却样品的SEM观察和EDS分析表明，穿透只发生在氧化铝膜的裂纹中。对铝颗粒熔化过程的现场观察和冷却后样品的SEM观察表明，在高温下，热应力使氧化铝膜破裂，铝液确实发生了流出。
Synopsis : Desulfurization and deoxidation of molten iron with magnesium vapor produced in-situ by aluminothermic reduction of magnesium oxide has been developed. In the present study, the mechanism of aluminothermic reduction of magnesium oxide by use of pellets composed of magnesium oxide and aluminum powders was discussed. SEM observation of the pellet at different reduction stages for various temperatures showed that fracture and disappearance of the alumina film on the aluminum particles were stimulated above 1473K, and thus the reduction of magnesium oxide was greatly accelerated. From in-situ observation of the aluminothermic reduction of magnesium oxide using a high temperature optical microscope (HTOM), it is found that the reduction proceeded after the penetration of molten aluminum into the magnesium oxide phase. The penetration began at 1273K, and it was accelerated above 1373K. The reduction took place violently at 1473K. SEM observation and EDS analysis of the cooled sample revealed that the penetration took place only through cracks of the alumina film. In-situ observation of the melting process of aluminum particles together with SEM observation of the cooled sample showed that the thermal stress could break up the alumina film and the outflow of molten aluminum did take place at the elevated temperature.