Study on the preparation of iron concentrate from copper smelting slag

Aiming at the problem of inefficient utilization of iron resources in flotation tailings of copper smelting slag, the distribution behavior and law of iron and silicon in the process of low-temperature alkaline smelting and leaching were studied, and the optimized process conditions were determined to prepare iron concentrate. The effects of melting time, melting temperature, the alkali-slag-ratio on the separation of silicon and iron and leaching time, liquid-solid ratio, and leaching temperature on the multielement leaching rate were studied. The optimum technological parameters were a melting temperature of 550℃, a melting time of 1.5 h, an alkali-slag mass ratio of 1.5:1, a leaching temperature of 40℃, the leaching time of 20 min, and a liquid-solid ratio of 15:1 mL/g. In the low-temperature alkaline smelting-leaching process, the total recovery rates of Fe and Si reached 99.43% and 91.22%, respectively. The iron grade of the iron concentrate was 61.82%, which met the iron standard of the third-grade iron concentrate in GB/T 25953-2010, and the content of all impurities except copper was lower than the limit value in the first-grade standard, which could be directly used in the iron and steel industry.