关键词: 铜冶炼渣, 深度还原, 磁选, 铁回收

Abstract: 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.

Key words: copper smelting slag, deep reduction, magnetic separation, iron recovery