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采用添加助熔剂直接还原焙烧-磁选方法,对镍主要以硅酸镍形式存在的低品位红土镍矿中镍和铁的富集进行了研究.结果表明,同时添加助熔剂,可获得较好的技术指标.最佳工艺条件为:煤作还原剂,质量分数为15%;KD-2为助熔剂,质量分数为20%;焙烧温度为1200℃;焙烧时间为40min.在此条件下可以得到镍品位10.83%、铁品位52.87%、镍回收率82.15%和铁回收率54.59%的镍铁精矿.用X射线衍射(XRD)和透射电镜(TEM)对还原过程中助熔剂和煤的作用机理进行了研究.发现KD-2可以与原矿中含镍的石英和硅酸盐矿物反应,释放出其中的镍;煤用量太多时可生成部分不含镍的金属铁,会造成镍的回收率降低.
The enrichment of nickel and iron in low-grade nickel laterite ore, mainly in the form of nickel silicate, was studied by direct reduction roasting-magnetic separation with flux addition.The results show that the addition of flux can achieve better results Of the technical indicators.The optimum conditions are as follows: coal as a reducing agent, the mass fraction of 15%; KD-2 as a flux, mass fraction of 20%; calcination temperature of 1200 ℃; baking time of 40min. Under these conditions The nickel-iron concentrate with 10.83% nickel grade, 52.87% iron grade, 82.15% nickel recovery and 54.59% iron recovery were obtained.The XRD and TEM were used to characterize the properties of the flux and coal Mechanism was studied.It is found that KD-2 can react with the nickel-bearing quartz and silicate minerals in the ore to release the nickel therein. When the amount of coal is too large, a part of the metal iron which does not contain nickel can be generated and the nickel recovery Lower rates.