Insights into the Flotation of Cassiterite-Containing Clinochlore with Hydrophobic Entrainment Based on EDLVO Theory

Clay minerals are a common gangue occurrence in tin ores. These clay minerals can enter the tin concentrate product through entailing the dilution of the tin grade of the flotation concentrate, resulting in poor flotation performance, and hence, the product loses value. The hydrophobic entrainment mechanism of clinochlore was systematically examined through flotation experiments. The flotation process demonstrated size-dependent entrainment characteristics of hydrophobic clinochlore, particularly showing enhanced particle migration into concentrates at elevated pulp concentrations. The slime coating formation mechanism was investigated through the integrated application of Extended Derjaguin-Landau-Verwey-Overbeek (EDLVO) modeling and SEM-EDS characterization. Critical interaction energy parameters required for EDLVO calculations were quantitatively determined via zeta potential analysis and hydrophobicity assessments using contact angle measurements. Computational results of EDLVO theory confirmed that the polar interfacial energy was the dominant energetic component to the total energy when the separation distance of cassiterite and clinochlore was less than 15 nm, and the two minerals could be attracted to each other. SEM-EDS observation verified that fine particles of clinochlore were attached to the surfaces of the unfloated cassiterite particles. This study fundamentally revealed the influence of clinochlore on cassiterite flotation.