Abstract: Siderite among Donganshan carbonates-contained iron ore usually makes the non-separation of concentrates and tailings in the reverse flotation of Donganshan Sinter Plant, resulting in the loss of the high carbonates ore. Therefore, artificial mixed minerals were adopted to investigate the effect of siderite on the reverse flotation of martite and quartz. Then, stepped flotation experiments of artificial mixed minerals and mixed magnetic concentrate of Donganshan high carbonates-contained hematite ores were carried out, where about 9.13% of siderite are removed at the first step of direct flotation in the close-circuit tests of mixed magnetic concentrate, and good index with iron concentrate of Fe grade 66.34% and recovery 71.60% was obtained in close-circuit experiment of the reverse flotation at the second step. All these approved that the stepped flotation is an effective flotation process for Donganshan high carbonates-contained hematite ore. 

Key words: Donganshan high carbonates-contained iron ore, Siderite, Reverse flotation, Stepped flotation