氢气还原制备MoO_2粉末工艺参数研究

Technological parameters study of MoO_2 powder prepared by hydrogen reduction

MoO3到MoO2的还原符合连续还原机理,有中间相Mo4O11生成。基于此理论,本文结合工厂实际生产,对MoO3氢气一段还原过程的主要参数进行了研究,并对过程进行了表征分析。还原温度小于540℃时还原效率过低;还原温度大于540℃时,MoO3的还原过程不易被控制,还原产物结块加重,温度是控制还原率的最主要参数。同时,还原率随着料层厚度的增加而变缓,随着还原时间的增长而增大。产物形貌从不规则颗粒向尺寸均匀的片层状结构演变。不同料层位置的还原产物的物性和微观形貌出现差异变化,还原效率受气体的扩散阻力影响。

MoO3 to MoO2 reduction reaction conforms to continuous reduction mechanism,with mesophase Mo4O11 generated. Based on this theory,main parameters in the one-stage reduction of MoO3 by H2,were studied and the process was characterized by combining with actual production conditions in factory. If reduction temperature is below 540 ℃,reduction efficiency will be too low; if reduction temperature is above 540 ℃,MoO3 reduction process cannot be easily controlled,causing the serious agglomeration problem; so temperature is the key parameter to control reduction efficiency. Study results show that reduction rate will slow with the increase of material thickness and increase with the increase of reduction time. Reduzate morphology will evolve from irregular particle to flake structure with uniform dimension. The physical properties and microstructure of reduzate vary with different material layer position,and reduction rate will be affected by the diffusion resistance of gas.