Flotation of low-grade bauxite using modified humics as depressant

Abstract

The low-grade bauxite, which is abundant in China, cannot be directly used in Bayer process. Flotation of low-grade bauxite is an effective way to improve the grade. Flotation experiments were carried out by using modified humics as depressant in this paper. The effects of pulp pH, collector dosage and depressant dosage were examined. Under the optimal flotation conditions with sodium oleate dosage of 2200 g/t, modified humics dosage of 10 g/t, pulp pH 10.0, the alumina to silica mass ratio (A/S) of flotation concentrate increased to 7.5. The recovery of aluminum minerals reached to 72.29%. Experiments results indicated that modified humics can be used as an effective depressant to improve A/S of low-grade bauxite.