The effects of carbonate minerals(dolomite and siderite) on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared(FTIR) spectroscopic studies, and X-ray photoelectron spectroscopy(XPS) analyses. The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests confirmed that both the cations(Ca~(2+) and Mg~(2+)) and CO_3~(2+)ions dissolved from dolomite depressed hematite flotation, whereas only the 23CO-ions dissolved from siderite were responsible for hematite depression. The zeta-potential, FTIR spectroscopic, and XPS analyses indicated that Ca~(2+), Mg~(2+), and CO_3~(2-)(HCO_3~-) could adsorb onto the hematite surface, thereby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation. The effects of carbonate minerals (dolomite and siderite) on the flotation of hematite using sodium oleate as a collector were investigated through flotation tests, supplemented by dissolution measurements, solution chemistry calculations, zeta-potential measurements, Fourier transform infrared (FTIR) spectroscopic studies, The results of flotation tests show that the presence of siderite or dolomite reduced the recovery of hematite and that the inhibiting effects of dolomite were stronger. Dissolution measurements, solution chemistry calculations, and flotation tests that both the cations (Ca ~ (2+) and Mg ~ (2+)) and CO_3 ~ (2+) ions dissolved from dolomite depressed hematite flotation, but only the 23CO-ion dissolved from siderite were responsible for hematite depression. zeta-potential, FTIR spectroscopic, and XPS analyzes indicate that Ca 2+, Mg 2+, and CO 3 2- (HCO 3 -) could adsorb onto the hematite surface, the reby hindering the adsorption of sodium oleate, which was the main reason for the inhibiting effects of carbonate minerals on hematite flotation.