铁精粉氧化过程的动力学研究
Kinetics study on oxidation of iron ore concentrate
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摘要: 通过恒温和均匀升温实验,采用大载荷热重分析仪研究了铁精粉氧化过程动力学.结果表明:均匀升温过程中,铁精粉氧化的主要控制环节变化是外扩散型→内扩散型→外扩散型,氧化结束后,部分Fe2O3发生分解反应生成Fe3O4和O2,使得TG曲线质量变化率减小;等温实验也证明了氧化主体部分的控制环节是内扩散,其表观活化能为26.193kJ·mol-1;铁精粉氧化过程促进了钛元素富集,改变了产物的微观结构.Abstract: Isothermal and uniform temperature-rise experiments were done to study the oxidation kinetics of iron ore concentrate with a TG instrument. The results indicated that the major control unit of the oxidation process changed from out-diffusion to inner-diffusion, and out-diffusion finally during uniform temperature rise. After oxidation, partial hematite decomposed into magnetite and oxygen; as a result, the mass change ratio on the TG curve gradually decreases. The isothermal experiment also proves that the main step is inner-diffusion and the apparent activation energy of oxidation is 26.193 kJ·mol-1. Oxidation of iron ore concentrate accelerates titanium enrichment and changes the microstructure of oxidized products.