钙基提钒尾渣强化还原-磁选分离钛铁技术研究

Study on the technology of enhanced reduction-magnetic separation of titanium and iron from calcium-based vanadium extraction tailings

采用直接还原-磁选方法从钒钛磁铁矿直接提钒尾渣中回收Fe,在还原温度1250℃、还原时间2 h、还原剂用量为尾渣质量的20%的条件下,球团的金属化率为92.71%。在球团中加入5%CaCO_(3)并延长保温时间至6 h后,Fe晶粒的平均直径从14.53μm增加至25.39μm。通过对Fe晶粒的生长速率拟合发现,加入CaCO_(3)后,晶粒生长速率常数从0.26μm^(2)/min提高至1.45μm^(2)/min。加入CaCO_(3)的直接还原球团经过磁选后,可以得到TFe含量为90.72%的直接还原铁和TiO_(2)含量为41.75%的含钛渣,Fe的回收率达到了91.05%,大幅提高了钒钛磁铁矿的资源利用率。

In this paper, the direct reduction-magnetic separation method was used to recover Fe from vanadium titano-magnetite(VTM) tailings. Under the conditions of reduction temperature 1 250 ℃, reduction time 2 h and reducing agent dosage 20% of the mass of the tailings, the metallization rate of pellets was 92.71%. After adding 5% CaCO_(3)and prolonging the holding time to 6 h, the average diameter of Fe grains increased from 14.53 μm to 25.39 μm. By fitting the growth rate of Fe grains, it was found that the grains growth rate constant increased from 0.26 μm^(2)/min to 1.45 μm^(2)/min after adding CaCO_(3).After magnetic separation, the direct reduced iron with TFe content of 90.72% and the titanium slag with TiO_(2)content of 41.75% could be obtained. The recovery rate of Fe reached 91.05%, which greatly improved the resource utilization of VTM.