Magnesite-dolomite separation using potassium cetyl phosphate as a novel flotation collector and related surface chemistry

•PCP acts as a selective collector for flotation separation of magnesite from dolomite.•Presence of dolomite in binary mixtures has detrimental effects on separation.•Sodium silicate as a modifier can restore the conditions for selectivity in the separation.•Zeta potential, wettability and XPS techniques were used in the study of mechanisms. To investigate the separation effect of magnesite from dolomite using potassium cetyl phosphate (PCP) as a collector, flotation experiments were carried out. In this study, the results obtained from the single minerals experiments showed an excellent selectivity with high recoveries for magnesite using PCP as the collector in contrast to the case with dolomite. The separation effect of the binary mixtures at pulp pH 9.0 was also investigated. The results confirmed that the PCP is an appropriate collector for the flotation separation of magnesite from dolomite. Surface chemical aspects of the separation mechanism were investigated through measurements of zeta potential, contact angle, and X-ray photoelectron spectroscopy analysis. The results support the flotation selectivity observed and are consistent with chemisorption of PCP on magnesite in the presence of sodium silicate that was used as a modifier to stabilize hydrophilicity of dolomite and remove its adverse effect on the recovery of magnesite.