Abstract: Dolomite is the main calcium-containing impurity of low quality magnesite ore. However, the similar crystal structure and composition resulted in the difficult flotation separation of dolomite and magnesite. Developing novel and efficient collectors is the main means to improve the separation efficiency of magnesite and dolomite. Based on this, sodium dodecyl sulfate (SDS) was used as the collector of dolomite. The effects of slurry pH value, collector concentration and soluble ions of Ca²⁺, Mg²⁺ and Fe³⁺ on the flotation performance of magnesite and dolomite were investigated. The results showed that a better flotation separation result was obtained when the SDS concentration was 20×10⁻⁵ mol/L and pulp was 10. The ions of Ca²⁺ and Mg²⁺ could simultaneously inhibit the flotation of magnesite and dolomite, which had little effect on the flotation difference of the two minerals. The inhibitory of Fe³⁺ on dolomite was weaker than that of magnesite, which was conducive to the flotation separation. The FTIR and Zeta potential results indicated that the adsorption capacity of SDS on the dolomite surface was much greater than that on the magnesite surface, and Fe³⁺ could promote the SDS adsorption on the dolomite surface and inhibit the SDS adsorption on the magnesite surface, thus increasing the flotation difference between dolomite and magnesite.