深度还原-弱磁选回收稀土尾矿中铁的试验研究

Test Research on Recovery of Iron from Rare Earth Tailings by Depth Reduction Roasting-Low Intensity Magnetic Separation

对某全铁品位为16.25%的稀土尾矿进行了深度还原-弱磁选回收铁试验研究,研究了还原剂种类及用量、焙烧温度及时间、磨矿细度及磁场强度对铁精矿品位和回收率的影响,并采用SEM,XRD等手段对稀土尾矿、焙烧产物、铁精矿进行了测试.结果表明,在烟煤质量分数30%,焙烧温度1 300℃,焙烧时间60 min,磨矿细度-0.074 mm占75%,磁场强度118 kA/m的条件下,所得铁精矿TFe品位可达80.76%,铁回收率可达93.24%;稀土尾矿经深度还原后,其中的赤、褐铁矿、硅酸铁等含铁矿物转化为单质铁,铁精矿品位和回收率较常规选矿方法大幅度提高,同时脉石矿物组成简单,有利于萤石的富集回收.

A process of depth reduction roasting-low intensity magnetic separation was introduced to the rare earth tailings with an iron grade of 16.25%.The effects of processing parameters,such as the type and dosage of reducing agent,roasting temperature,roasting time,grinding fineness and magnetic field intensity on the iron grade and recovery of the concentrate were investigated.And the means of SEM,XRD were used to analyze the rare earth tailings,the roasted products and the iron concentrate.The results showed that an iron concentrate with TFe grade of 80.76% and recovery of 93.24% was obtained under the condition of bituminous coal dosage of 30%,roasting temperature of 1 300 ℃,roasting time of 60 min,grinding fineness of-0.074 mm accounted 75% and magnetic field intensity of 118 kA/m.After depth reduction,iron-bearing minerals in the tailings,such as hematite,limonite and iron silicate,translated into simple substance iron.Compared with the conventional separation methods,the iron concentrate grade and recovery increased more significantly and the gangue minerals composition was simple,which was helpful for enrichment and recovery of fluorite.