Abstract

Sylvite (KCl) is a classical soluble mineral with high solubility, endowing the possibility to precisely adjust its surficial structure for flotation recovery. In this work, efforts have been originally made to study flotation behaviors of KCl with (200) and (222) exposing facets. KCl(200) crystals had a higher recovery than that of KCl(222) with octadecylamine hydrochloride (ODA). FTIR and XPS results indicated that interaction force between KCl and ODA was not chemical absorption. Zeta potential results further implied the mechanism that the ODA reacted with KCl by static force and KCl(200) possessed a lower potential than KCl(222) and thus facilitated the flotation process. 2D as well as 3D AFM results provided microscopic details of perfect cubic KCl(200) and octahedron KCl(222) samples where layered growing method of former samples exhibited more edges with hanging Cl bonds, leading to its more negative surficial potential and less hydrophilic property, enhancing flotation recovery. Moreover, adhesion & adsorption force further illustrated that KCl(200) obtained a stronger interaction with bubbles, in coincidence with its better flotation recovery. KCl crystals with (200) exposing faces promoted flotation in comparison with crystal with (222) faces, offering strategy to reserve (200) faces for designing KCl crystals with high recovery.