铜冶炼渣中铁的生物炭深度还原—磁选回收试验

铜冶炼渣中铁含量达30%~40%，但铁元素主要以铁橄榄石的形式存在，采用传统方法难以回收利用。以可再生生物炭为还原剂，通过深度还原—磁选回收铜冶炼渣中的铁，考察了还原条件对铜冶炼渣深度还原的影响。当还原温度为1 200 ℃、还原时间为75 min、CaO用量10%、碳氧摩尔比为1.5时，深度还原产品的金属化率达到86.83%，经过磨矿磁选可获得铁品位为62.84%、回收率为81.92%的磁选精矿。铜冶炼渣中主要含铁矿物有Fe2SiO4、Fe3O4及少量的Fe2O3，其还原过程为Fe2SiO4→FeO→Fe、Fe2O3→Fe3O4→FeO→Fe，得到的金属铁逐渐聚集长大最终形成有利于磁选分离的金属铁颗粒。

Study on Iron Recovery from Copper Smelting Slag by Deep Reduction with Biochar and Magnetic Separation

The iron content in copper smelting slag is 30%~40%,but the iron element mainly exists in the form of iron olivine,which is difficult to be recycled by traditional methods.The iron was recovered from copper smelting slag by deep reduction and magnetic separation using renewable biochar as reducing agent.The effect of reduction conditions on deep reduction of copper smelting slag was investigated.When the reduction conditions were reduction temperature of 1 200 ℃,reduction time of 75 min,CaO dosage of 10% and molar ratio of carbon and oxide of 1.5,the metallization rate of deep reduction product reached 86.83%.Magnetic concentrate with iron grade of 62.84% and recovery rate of 81.92% was obtained by grinding and magnetic separation.The main iron bearing minerals in copper smelting slag are Fe2SiO4,Fe3O4 and a small amount of Fe2O3.The reduction process is Fe2SiO4→FeO→Fe,Fe2O3→Fe3O4→FeO→Fe,and the obtained metal iron gradually gathers and grows up,finally forming metal iron particles that are beneficial to magnetic separation.