Abstract: The paper describes the technological mineralogy and flotation-separation characteristics of Donganshan carbonate-containing refractory iron ore and puts forward a new process for treating this kind of ore, stepped flotation. It consists of first separating the siderite by direct flotation in neutral medium and then separating hematite by indirect flotation. The closed-circuit laboratory test results show that an iron concentrate grading 66.34% iron with an iron recovery of 71.6% can be obtained from a flotation feed grading 52.3% by stepped flotation process.

Key words: Stepped flotation, Siderite, Direct flotation, Hematite, Indirect flotation