微波加热含锌粉尘的物相形貌特征及还原过程研究

含锌粉尘和煤粉按质量比4:1混合形成混合粉。采用化学分析和扫描电镜对混合粉的成分和物相进行分析,研究大气常压下微波加热还原混合粉在不同时间下的显微物相形貌特征以及混合粉的还原过程。结果表明:微波加热7 min时,混合粉物相中出现金属铁相、浮氏体相和渣相;随时间的延长,金属铁相逐渐增大、浮氏体相逐渐减小、渣中的锌含量逐渐减少,20 min时,浮氏体相消失,渣中已很难找到锌元素;混合粉的脱锌率和金属化率随加热时间的延长不断提高,加热20 min,金属化率均能达到80%以上,脱锌率在前10 min提高明显,能达到67%。

铁浴法处理不锈钢粉尘的研究

采用扫描电子显微镜和X射线能谱分析仪对不锈钢粉尘的矿相进行分析,研究铁浴法还原不锈钢粉尘回收镍铬的效果,及铁浴条件下温度、配碳量、反应时间对不锈钢粉尘还原的影响。结果表明:粉尘表面铁、镍、铬、锌含量与粉尘颗粒大小无关;不同尺寸的不锈钢粉尘对铁、镍、铬、锌元素不存在选择性吸附规律;影响镍铬回收率的3个因素中,配碳量最为显著,其余依次是反应时间和铁浴温度;回收镍铬实验的最优化方案为铁浴温度1 610℃,配碳量(质量分数)20%,反应时间40 min,其镍铬回收率分别可达87.9%和83.5%。

Phase transitions, micro-morphology and its oxidation mechanism in oxidation of ilmenite (FeTiO_3) powder

Phase transitions, morphology changes, and oxidation mechanism of the ilmenite oxidation process were investigated. FeTi03 transforms to hematite and rutile when oxidation at 700-800 ℃, and pseudobrookite is formed when the oxidation temperature reaches 900 ℃. The initial ilmenite powder exhibits paramagnetism; however, after being oxidized at the intermediate temperature （800-850 ℃）, the oxidation product exhibits weak ferromagnetism. The oxidation mechanism was discussed. The microstructure observations show that a lot of micro-pores emerge on the surfaces of ilmenite particles at the intermediate temperature, which is deemed to be caoable ofenhancin~ the mass transfer ofoxgen during oxidation.