DHX collector for recovery of cassiterite: Mechanistic insights and practical implications

Abstract

This study addresses the efficiency and sustainability of tin resource utilization by exploring a novel collector, C16H33NO2 (DHX), in cassiterite flotation. DHX demonstrated superior collection efficiency and a broader effective pH range in micro-flotation tests. A peak cassiterite recovery of 92.2% was achieved with DHX at pH 7.5 ± 0.3, while BHA could achieve only 69.6%. Furthermore, DHX consistently maintained a recovery above 70% in a wide pH range from 3 to 11. The capacity of DHX to separate cassiterite from calcite in mixtures underlines its remarkable selectivity. Zeta potential and contact angle measurements showed strong DHX adsorption on cassiterite surfaces, leading to marked enhancements in hydrophobicity and potentially augmenting flotation efficiency. FTIR and XPS analyses further confirmed the formation of a stable ring structure between the hydroxy and oxime groups in DHX anions and Sn ions on the cassiterite surface. In practical applications, such as a copper-zinc-tin polymetallic mine in Yunnan, China, DHX exhibited promising recovery results in gravity separation tailings. Bench-scale flotation tests on tin-bearing tailings (0.21% Sn) resulted in a concentrate with a tin grade and recovery rate of 2.15% and 61.27%, respectively. These results highlight DHX’s immense potential as a cassiterite flotation collector, outperforming conventional alternatives in performance.