Theoretical and experimental study on high-entropy flotation of micro-fine cassiterite

Abstract

Tin is a critical metal for various industries, making its recovery from low-grade cassiterite ores crucial. This study aimed to optimize the flotation recovery of cassiterite using multi-component collector systems. Several collectors were initially selected through micro-flotation tests, leading to the identification of optimal proportions for a four-component collector system (SHA-OHA-SPA-DBIA in a 4:3:2:1 ratio). Molecular dynamics simulations and surface tension tests were used to investigate the micellar behavior of these collectors in aqueous solution. The adsorption characteristics were quantified using microcalorimetry, enabling the determination of collection entropy and changes in Gibbs free energy. The four-component collector system showed the highest entropy change and the most favorable Gibbs free energy, leading to a cassiterite recovery of above 90% at a concentration of 8.0×10⁻⁵ mol/L. Various analytical techniques were employed to systematically characterize the adsorption mechanism. The findings revealed a positive correlation between the adsorption products formed by the multi-component collectors on the cassiterite surface and the entropy changes. Industrial-scale testing of the high-entropy collector system produced a tin concentrate with an Sn grade of 6.17% and an Sn recovery of 82.43%, demonstrating its substantial potential for practical applications in cassiterite flotation.