红土镍矿直接还原焙烧磁选回收铁镍

采用添加助熔剂直接还原焙烧-磁选方法,对镍主要以硅酸镍形式存在的低品位红土镍矿中镍和铁的富集进行了研究.结果表明,同时添加助熔剂,可获得较好的技术指标.最佳工艺条件为:煤作还原剂,质量分数为15%;KD-2为助熔剂,质量分数为20%;焙烧温度为1200℃;焙烧时间为40min.在此条件下可以得到镍品位10.83%、铁品位52.87%、镍回收率82.15%和铁回收率54.59%的镍铁精矿.用X射线衍射(XRD)和透射电镜(TEM)对还原过程中助熔剂和煤的作用机理进行了研究.发现KD-2可以与原矿中含镍的石英和硅酸盐矿物反应,释放出其中的镍;煤用量太多时可生成部分不含镍的金属铁,会造成镍的回收率降低.

Recovery of iron and nickel from nickel laterite ore by direct reduction roasting and magnetic separation

By adding a flux and using a direct reduction roasting and magnetic separation method,iron and nickel enrichment from refractory low-grade nickel laterite ore,in which nickel is mainly contained in silicates,was studied.Better technical indicators were obtained by adding the flux.The optimal conditions are coal as the reducer with a dosage of 15%,KD-2 as the flux with a dosage of 20%,and roasting at 1200℃ for 40min.A concentrate of the Ni content of 10.83% and the Fe content of 52.87%,with the Ni recovery of 82.15% and the Fe recovery of 54.59%,was produced under the optimal conditions.The action mechanisms of KD-2 and coal were also investigated by XRD and TEM.The results show that KD-2 can react with quartz and silicates containing Ni,leading to releasing Ni from the quartz and silicates.An overdosage of coal in the reduction roasting process can result in the formation of pure iron,in company with a decrease in nickel recovery.