蛇纹石矿物的高温相变对红土镍矿直接还原的影响

摘要

红土镍矿所含的蛇纹石矿物在焙烧过程中会出现脱羟基和重结晶等相变。选取两种不同试样进行直接还原焙烧−磁选实验，研究蛇纹石的高温相变对直接还原焙烧红土镍矿的影响。对两种红土镍矿进行热重分析、XRD衍射分析和扫描电镜分析，研究两种红土镍矿中的蛇纹石矿物在焙烧过程中相变过程的异同及其对直接还原的影响。结果表明：两种试样所含主要矿物为蛇纹石和针铁矿，其热重分析曲线相似；在焙烧过程中，试样2在较低温度下出现橄榄石相。在最终的焙烧矿物相中，与试样1相比，试样2中出现石英相；与试样2相比，试样1的蛇纹石颗粒内部在焙烧后形成较多裂隙。因此，试样2的镍回收率较低。%The phase transitions of dehydroxylation and recrystallization will happen in the roasting process of serpentine mineral in the laterite nickel ore. To study the effect of phase transition of serpentine on the direct reduction of laterite nickel ore, the direct reduction roasting−magnetic separation test was conducted on two samples. The similarities and differences of phase change of the two kinds of laterite nickel ore in the process of roasting and the influence on direct reduction roasting were analyzed by TGA, XRD and SEM. The results show that two kinds of samples contain the same main minerals of serpentine and goethite, and the TGA curves are similar. Olivine phase appears earlier in Sample 2 at low temperature in the roasting process. The quartz phase appears in the final roasting mineral phases of Sample 2 but not in that of Sample 1. Compared with Sample 2, there are more fracture in serpentine particles of Sample 1 after roasting. Therefore, the nickel recovery rate of Sample 2 is lower.