Effect of Surface Dissolution on the Floatability of Brucite in Three Anionic Collector Systems

Abstract This study investigated the relation between the solubility and floatability of the soluble mineral brucite, focusing on the concentration characteristics of dissolved Mg2+ in brucite under three dissolution methods and the surface characteristics after dissolution. Some common rules of brucite flotation in three anionic collectors were discovered. Results of a flotation test showed that for three anionic collector systems of sodium oleate, sodium dodecyl sulfonate, and oxidized paraffin soap, the flotation recovery rate of brucite, increased with the time of dissolution and decreased with the removal of dissolved Mg2+, but the flotation recovery rate is lower than that of untreated brucite. Inductively coupled plasma spectroscopy indicated that the content of dissolved Mg2+ in brucite slurry increases with increasing brucite content or dissolution time. Zeta potential measurements showed that the ability of dissolved Mg2+ to increase the surface potential of brucite follows the order of H2SO4 action > HCl action > H2O action. Adsorption capacity measurements showed that the presence of dissolved Mg2+ after dissolution is not beneficial for the adsorption of the three collectors on the surface of brucite. The capacity of the adsorption collectors follows the order of brucite after H2O dissolution > brucite after HCl dissolution > brucite after H2SO4 dissolution. Scanning electron microscopy and X-ray photoelectron spectroscopy analyses indicated that the surface dissolution promoted the dissolution of Mg2+ on brucite surface in the solution, reducing the number of Mg sites on brucite surface and deteriorating the collection effect of the collector.