Abstract: The laboratory tests of reverse flotation were carried out in order to improve the low grade mixed concentrate of magnetic separation from a hematite ore concentrator by the countercurrent bubble contact flotation column. By systemic studies in the lab, the optimal operational conditions had been determined as follows: the feeding speed of 847mL/min, the pulp density of 35%, the inflatable volume 4.0m³/h, the foam layer height of 30mm. And the pharmaceutical dosage was NaOH 1250g/t, starch 1200g/t, CaO 600g/t and GK-58 650g /t. The results showed that a final iron concentrate with TFe grade of 65.82% and iron recovery of 62.79% from the magnetic concentrate with TFe grade of 42.15％was obtained by one roughing. The test data can provide some reference for the flotation column application in the hematite flotation process.