Abstract: After spiral chute gravity concentration of a sulfuric acid raw slag with 57.10% iron grade, iron concentrate with iron grade of above 62% is received but iron grade of tailings is high and iron recovery of concentrate is only 47.95%. Beneficiation comparison experiments of gravity concentration using centrifugal separator, magnetic—flotation separation, and desliming—flotation process were conducted for iron recovery increasing. The results showed that optimal result can received by desliming—flotation process, iron concentrate with iron grade of 59.97%, iron recovery of 42.65% was received for iron increase of tailings, thus mixed concentrate with iron grade of 61.52%, comprehensive recovery of 70.15% was achieved.

Key words: Sulfuric acid slag, Recycling iron from tailings, Gravity concentration, Magnetic—flotation separation, Desliming—flotation