Abstract: Through the single mineral flotation test, the flotation behavior of magnesite and dolomite in the dodecylamine flotation system and the influence of the regulator Fe³⁺ on the floatability of the two minerals were studied. Based on Fourier Infrared Spectroscopy (FTIR) and contact angle test, the mechanism of Fe³⁺ was studied. The flotation test results show that in the dodecylamine system, under the natural pH condition of the pulp, the floatability of dolomite is better than that of magnesite. There is a certain floatation difference between magnesite and dolomite, and the addition of a small amount of Fe³⁺ significantly improves the floatation difference of the two minerals. Infrared spectroscopy test results show that the adsorption of dodecylamine on the surface of dolomite is mainly electrostatic adsorption, dolomite CO₃²⁻ out-of-plane bending vibration and CO₃²⁻ in-plane bending vibration are almost unchanged, and -CH₃ and -CH₂ are symmetrical and asymmetrical. The peak value of extensional vibration increases. The contact angle test results show that the addition of a small amount of Fe³⁺ enhances the hydrophobicity of dolomite, which has the effect of activating dolomite.