New insights into the flotation response of brucite and serpentine of different conditioning time: Surface dissolution behavior

Gangue minerals inadvertently dissolution frequently plays a detrimental role on the flotation of valuable minerals. In this paper, the effect of conditioning time on the flotation separation of brucite and serpentine was investigated. By analyzing the Mg²⁺ concentration, the relative content of elements, and pulp viscosity, the effect of mineral dissolution on the brucite flotation was studied. The artificial mixed mineral flotation results (with -10 μm serpentine) showed that, with the conditioning time extended from 60 s to 360 s, a large amount of Mg²⁺ on the mineral surface gradually dissolved into the pulp, resulting in a decrease of brucite recovery (from 83.83% to 76.79%), whereas the recovery of serpentine increased from 52.12% to 64.03%. Moreover, the SEM observation was applied to analyze the agglomeration behavior of brucite and serpentine, which clearly demonstrated the difference of adhesion behavior under various conditioning time. Finally, the total interaction energy that carried out by extended DLVO (E-DLVO) theory also supports the conclusion that the gravitational force between brucite and serpentine increases significantly with the increase of conditioning time.