A novel activation scheme for fine cassiterite flotation by using a metal ion modified collector

Abstract

The large specific surface area of fine cassiterite poses significant challenges to its flotation recovery. Metal ions have been shown to enhance the flotation performance of collectors. This study investigated the influence and synergistic mechanism of silver ion and salicylhydroxamic acid on the flotation behavior of fine cassiterite. At a pH of 8, the addition of 5 × 10^–4 mol/L silver ion increased cassiterite recovery from 56.83 % to 83.36 %, thereby indicating the synergistic activation effect of silver ion on cassiterite flotation. Zeta potential and contact angle analyses indicated that silver ion facilitated the adsorption of salicylhydroxamic acid on the cassiterite surface, thereby enhancing the hydrophobicity of the cassiterite surface. The corresponding mechanism tests indicated that silver ion treatment changed the chemical environment of oxygen O atoms on the cassiterite surface, thereby facilitating the formation of C–H, C–N, and N–O bonds. This change was attributable to the adsorption of silver ion on O sites of the cassiterite surface, creating additional active sites for salicylhydroxamic acid and thereby enhancing flotation efficiency. Atomic force microscopy imaging analysis indicated that silver ion pre-activation formed new hydrophobic layers on the cassiterite surface, which enhanced the adsorption capacity and stability of salicylhydroxamic acid. Thus, the flotation of fine cassiterite remains a persistent global challenge. This study offered an enhanced recovery strategy for fine cassiterite flotation.