硫酸钠作用下褐铁型红土矿选择性还原富集镍铁

Selective Reduction and Enrichment of Nickel and Iron in Limonitic Laterite Ore with the Addition of Sodium Sulfate

以Na2SO4为添加剂,采用煤基还原-磁选工艺,对含Ni 1.17%和Fe 35.71%的褐铁型红土矿选择性还原富集镍铁的行为进行了研究.结果表明,原矿中27.40%的镍以氧化物形式存在,69.35%的镍以硅酸盐形式存在;在还原温度1100℃、还原时间60 min、硫酸钠用量20%(?)、无烟煤用量8%(?)的最佳还原条件下,在200 m T的磁场强度下湿式磁选,可富集得到镍品位13.26%、镍回收率88.4%、铁品位67.34%、铁回收率14.71%的镍铁精矿,镍富集比达11.33.红土镍矿还原过程中加入Na2SO4破坏了原矿中硅酸盐的结构,释放出其中的镍与铁,进一步生成Fe S,抑制铁深度还原并降低了体系熔点,有利于金属离子传质,促进镍铁颗粒长大.

The limonitic laterite ore containing 1.17% Ni and 35.71% Fe by the coal-based reduction-magnetic separation process was studied using sodium sulfate as additive. The results showed that nickel was mainly associated with oxides（27.40%） and silicates（69.35%） in ore. For a ferronickel content of 13.26% Ni and 67.34% Fe, nickel recovery rate of 88.40%, iron recovery rate of 14.71% could be obtained under the best conditions of reduction temperature 1 100 ℃, reduction time 60 min, the mass fraction of additive 20% and reductant 8% by the application of a 200 m T magnetic field, the enrichment ratio of nickel reached 11.33. Addition of sodium sulfate destroys the silicate mineral structure, and the majority of nickel and iron is liberated from silicates, Fe S could also be generated. The formation of Fe S inhibits the reduction of iron, decreases the system melting point, intensifies the process of metal irons mass transfer and enhances ferronickel particles growth during the reduction of laterite.