微波加热含碳氧化锰矿粉体还原动力学研究

Kinetics of Voluminal Reduction on Manganese Oxide Ore Fines Containing Coal by Microwave Heating

含碳氧化锰矿粉在微波场中的升温和还原过程均对微波具有较好的吸收性.在C/O原子摩尔比为1.06,CaO/SiO2分子摩尔比为1.27的条件下,微波加热到1000,1100,1200,1300℃时,物料的升温速率分别为52.63,50.00,48.00,37.14℃/min.随着微波加热温度的提高和保温时间的延长,还原物料的金属化率随之增加,在1300℃时还原物料的金属化率达到9.08%.微波加热含碳氧化锰矿粉体还原反应的活化能非常低(9.90kJ/mol),表明界面化学反应不是限制性环节,而CO气体向锰矿粉颗粒的内扩散是反应的主要限制环节.

Manganese oxide ore fines containing coal (MOOFCC) in microwave field have good property of absorbing microwave in the process of temperature rising and reduction. Under the conditions of atomic molar ratio of O to C as 1:1.06 and molecular molar ratio of SiO2 to CaO as 1:1.28,the temperature rising rates of MOOFCC by microwave heating to reach 1000,1100,1200 and 1300℃ are 52.63,50.00,48.00 and 37.14℃/min,respectively. With the temperature increasing of microwave heating and holding time prolonging,the metallization rate of the materials reduced increases,for example,the metallization rate of 9.08% at 1300℃. The apparent activation energy of voluminal reduction on MOOFCC by microwave heating is very low (9.90 kJ/mol),which shows that interface chemical reaction is not the restrictive step,but the internal diffusion of CO toward MOOFCC is the main restrictive step.