微波场中锰矿粉碳热还原反应研究

Study on Carbothermal Reduction Process of Manganese Ore in Microwave Field

采用微波加热和常规加热对锰矿粉的碳热还原反应进行了研究.利用热重分析仪研究温度、粒度和碳氧原子摩尔数比等因素对微波场中锰矿粉碳热还原反应速率的影响,并通过拟合得到碳热还原反应过程动力学方程,进而得到微波加热相对于常规加热碳热还原的速率增加因子Q.实验结果表明:在微波加热时,随着碳氧原子摩尔数比的升高,物料升温速率随之提高;同时,反应前期升温速率较大,随着反应的进行,升温速率逐渐降低.提高碳氧原子摩尔数比和温度,微波加热碳热还原反应速率加快.减小粒度可以提高反应速率,但当粒度减小到150目时,进一步减小粒度后,反应速率不会有明显的提高.相同的温度和保温时间下,微波加热失重率远大于常规加热,微波加热的促进作用在低温和低温反应后期更为显著.

Carbon thermal reduction reactions of manganese ore powder by microwave heating and conventional heating were investigated. The effects of temperature, particle size and carbon-oxygen ratio on the re- duction rates by microwave heating were studied by thermogravimetric analyzer. Afterwards, the dynamic equation of the carbothermal reduction process was obtained by fitting regression, and the rate-increasing factor Q which characterized the rate increase of microwave heating with respect to conventional heating was obtained. The results showed that the material heating rate augmented with the increase of carbon-oxygen ratio, and the heating rate was performed rapidly at the initial stage and then gradually decreased by microwave heating. The increase of both tem- perature and carbon-oxygen ratio could accelerate the reaction rate. The reaction rate was also significamly increased with the reduction of ore particle diameter till 150 mesh. Moreover, the weight loss of reduction reaction by microwave heating was much larger than that by conventional heating under the same temperature and heat preservation time. It indicated that microwave heating performed evident effect on speeding up the reaction rate at the low temperature and late stage.