碳热还原-磁选工艺富集红土镍矿中金属镍

Enriching Metallic Nickel from Laterite-Nickel Ore via Thermal Carbon Reduction-Magnetic Separation Process

采用碳热还原-磁选富集镍的工艺处理低品位红土镍矿,以活性炭粉为还原剂,在还原球团内加入添加剂A以促进还原球团中金属晶粒的生长及磁性物质与非磁性物质的磁选分离,使红土镍矿在低于传统的熔炼温度下进行还原反应,可大大降低能量消耗.研究结果表明,最佳反应条件:还原温度为1 320℃,还原时间为1 20 min,还原剂与添加剂的质量分数分别为3%及5%;添加剂可促进金属晶粒的聚集,富集的金属晶粒更易于磁选分离;还原产品镍铁合金中镍的质量分数可达8.31%,矿石中镍的回收率可达95.44%,金属镍得到了富集.本工艺具有流程短、操作简单、能耗低及镍铁合金的经济价值高等优点.

The low-grade laterite-nickel ore was treated by thermal carbon reduction-magnetic separation process to enrich the metallic nickel with activated carbon powder as reductant.With the additive A added in the pre-reduced pellets to stimulate the growth of metallic grains in them and magnetic separation of magnetic substance from nonmagnetic substance,the reduction reaction of laterite-nickel ore occurred at the temperature below conventional melting point,thus,reducing greatly the energy consumption.The testing results showed that the optimal reduction conditions are 1 320 ℃ for 120 min and the proportional mass fractions of activated carbon powder and the additive A are 3% and 5%,respectively.The additive A accelerates the aggregation of metallic grains so as to make the enriched metallic grains easier for magnetic separation.The mass fraction of maximum nickel in ferronickel alloy and nickel recovery in the laterite-nickel ore are 8.31% and 95.44%,respectively.Metallic nickel is thus enriched.The proposed process has such advantages as short in procedure,easy to operate,low energy consumption and high economic benefit from ferronickel alloy.