CaO在红土镍矿直接还原焙烧中的作用机理

摘要

以Ni和Fe质量分数分别为1.46%和26.68%的红土镍矿为研究对象，进行直接还原焙烧−磁选试验研究，并对焙烧矿进行X线衍射(XRD)与扫描电镜(SEM)分析以研究CaO的作用机理。研究结果表明：使用含CaO的组合添加剂能够达到磁选精矿中镍质量分数为8.58%、回收率为88.15%的最佳试验效果。在直接还原焙烧过程中，添加的CaO能够在焙烧过程中与硅酸盐矿物反应生成辉石、提高含镍硅酸盐的反应活性、促进镍的还原并且能够降低还原过程中NiO与SiO 2结合的概率，提高镍的回收率。%The direct reduction roasting-magnetic separation experiment was conducted on nickel laterite sample graded 1.46% Ni and 26.68% Fe, and X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were conducted to to investigate the mechanism of CaO. The results show that it can achieve the best results with nickel grade of 8.58%, recovery grade of 88.15% by using composite additives containing CaO. In the process of direct reduction roasting, CaO can react with silicate minerals to generate pyroxene, which can increase the reactivity of silicate bearing nickel and promote the reduction of nickel. It can also reduce the probability of NiO combined with SiO2 again in the reduction process and improve the recovery of nickel.