中文摘要：

对某低品位腐殖土型红土镍矿（镍和铁质量分数分别为1.01%和15.72%）进行压块—还原焙烧—磁选试验,研究还原温度、还原时间、复合添加剂用量和预热温度对镍和铁回收效果的影响。研究结果表明：在碱度（即CaO与SiO2质量比）为0.2、复合添加剂质量分数为14%、预热温度为900℃、预热时间为15 min、还原温度为1 250℃、还原时间为35 min、煤与矿质量比为2.7、磨矿细度小于0.074 mm的质量分数为（95±4）%、磁选磁场强度为131.34 kA/m的条件下,获得镍和铁品位分别为4.22%和69.75%的镍精矿,镍和铁回收率分别为92.22%和85.73%;适宜的预热制度有利于团块中镍、铁的富集;复合添加剂促进了镍铁晶粒的聚集、长大,提高了镍、铁回收效果。

英文摘要：

The enrichment of Ni from a low-grade saprolite laterite assaying with 1.01% Ni and 15.72% Fe was studied through briquetting-reduction-magnetic separation process and the effects of reduction temperature, reduction duration, dosage of composite additive, preheating temperature on the recovery of Ni and Fe were examined to optimize the process. The results show that nickel concentrate with 4.22% Ni and 69.75% Fe was achieved with recoveries of 92.22% and 85.73% for Ni and Fe respectively at the following conditions： basicity （mass ratio of CaO to SiO2） 0.2, dosage of composite additive 14%, preheating at 900℃ for 15 rain, reduction at 1 250 ℃ for 35 min, mass ratio of coal to ore 2.7, grinding fineness of （95±4）% passing 0.074 mm and magnetic intensity of 131.34 kA/m, the enrichment of Ni and Fe is improved by preheating the briquettes of laterite ores. The composite additive can promote the growth of ferro-nickel grains, enhance the separation process and improve the recovery of Ni and Fe.