固态氧化铝碳热还原反应研究进展

摘要

The carbothermal reduction of solid alumina is used and studied extensively in ceramic material and aluminum smelting; however, there still exist different viewpoints on its mechanism. The solid and gaseous products of the carbothermal reduction of alumina are introduced and the three main mechanisms are presented in this work. It is suggested that the alumina decomposition mechanism is reasonable, whilst the solid­solid reaction mechanism lacks for direct evidences, and the gas­solid reaction mechanism disagrees with the thermodynamic analysis and the experimental results. The possible mechanism is proposed as follows:alumina decomposes to Al­containing gases and oxygen, then carbon reacts with oxygen to reduce oxygen partial pressure, and the Al­containing gases react further to form the final products being aluminum carbide, aluminum oxycarbide and etc at reduced pressures or in argon, and being aluminum nitride in nitrogen. Furthermore, some future research directions are recommended for the systematic interpretation on the mechanism of the carbothermal reduction of solid alumina.%　　固态氧化铝碳热还原反应在陶瓷材料及铝冶金领域得到广泛的应用和研究，但其反应机理至今未能得到统一的认识。介绍氧化铝碳热还原过程形成的固态、气态产物，阐述3种主要反应机理。提出固−固相反应机理缺乏直接证据，气−固相反应机理与热力学分析及实验不符，而氧化铝分解反应机理较合理。可能的反应机理如下：氧化铝分解为含铝气体和氧气，碳与氧气反应以降低氧分压，含铝气体再次反应形成最终产物，在减压或氩气下形成碳化铝、碳氧化铝等，在氮气下形成氮化铝。并提出了系统解释固态氧化铝碳热还原反应需要继续研究的方向。