硫酸渣复合球团还原焙烧法制备高品位磁铁精矿

magnetic-separation Preparation of high quality magnetite concentrate from pyrite cinder by composite pellet reduction-roasting and

进行了硫酸渣复合球团还原焙烧-磁选实验。研究结果表明:以铁品位低(TFe 45.56%)、铜和硫含量高(Cu 0.19%,S 1.45%)的某硫酸渣为原料,添加复合添加剂5%,在圆盘造球机上制备复合球团,将生球干燥后进回转窑还原焙烧,往每吨复合球团中喷入煤300 kg,在700～800℃还原焙烧20 min,将还原焙烧后产物通过两段球磨、四段磁选工艺,可得到铁品位高(总铁含量为66.23%),Cu和S含量低(Cu 0.048%,S 0.053%)的优质磁铁精矿,其铁回收率达73.32%,铜脱除率达74.73%,硫脱除率达96.34%。实验的关键技术是复合粘结剂促进铁氧化物的还原及铜、硫等杂质的转化,在磁选分离过程中脱除杂质。使用此新工艺,能综合利用硫酸渣中铁资源,扩大钢铁工业原料来源。

A new technology of composite pellet reduction-roasting and magnetic-separation （CPRM） was developed for utilization of pyrite cinder, a common by-product in vitriol industry. Pyrite cinder, containing 45.56% Fe, 0.19% Cu and 1.45% S, was pelletized with addition of 5% composite agent in bailing disc. Green balls after drying were reduced at 700-800℃ for 20 min with 300 kg/t pulverized coal injection in rotary kiln. After two-stage ball-grinding and four stages magnetic separation, magnetite concentrate with iron grade of 66.23% Fe and containing 0.048% Cu and 0.053% S were made. And iron recovery of 73.32%, desulphurization degree of 96.34% and decoppering degree of 74.73% were achieved. Key technique is that composite agent can accelerate reduction of Fe203 and transfer copper and sulphur into water-soluble inorganic salts, which are removed during wet magnetic concentration. This new technology can be used to fully utilize pyrite cinder and produce high quality magnetite concentrate as iron-bearing feed for steel industry, which will help to solve the pollution of pyrite cinder and extend raw material sourcing for Chinese steel industry.