Study on recovery of iron and sulfur from high-sulfur magnetite ore

In this paper, to produce a saleable magnetite concentrate with a sulfur level below 0.20% and recover sulfur concentrate, flotation and magnetic separation tests were undertaken. Results showed that the optimum conditions of flotation were established as follows: grinding fineness of 90% particles passing 0.074mm, pH 6, 400 g/t of CuSO4, and 400 g/t of combined collectors. Under these conditions and magnetic separation, S grade of the magnetite concentrate was reduced from 3.20% to 0.18%, and the Fe grade improved from 57.29% to 71.17%. At the same time a sulfur concentrate with S grade of 38.05% and recovery of 91.32% was also obtained. The XPS results showed that the addition of CuSO4 benefited the formation of hydrophobic Sn2-/S0 and Cu+-xanthate, enhancing pyrrhotite floatability. The flotation separation efficiency could be enhanced using a mixture of collectors, and collector mixture demonstrated three synergetic effects, namely enhanced S recovery, improved adsorption behavior of the collectors and enhanced hydrophobicity of pyrrhotite surface.