Flotation behavior and mechanism of smithsonite under the system of bidentate ligand sulfide sodium thiocyanate

Abstract

The sulfuration pretreatment is essential in enhancing the floatability of zinc oxide ore during the flotation process. The conventional vulcanizing agent employed in the sulfuration process, however, has proven to be ineffective and environmentally unfriendly. The dosage of this agent must be strictly regulated to ensure optimal flotation efficiency of zinc oxide ore, as excessive or insufficient amounts can have a negative impact. To address these issues, a more efficient and environmentally friendly vulcanization agent called sodium thiocyanate (NaSCN) has been introduced to enhance the sulfuration flotation of smithsonite. It also demonstrated the effective sulfidation of smithsonite by sodium thiocyanate, which also exhibits superior vulcanization effects compared to sodium sulfide. By applying NaSCN at a concentration of 6 × 10-4 mol/L, the recovery rate of zinc ore can achieve 88.75 %. Moreover, the vulcanization conditions utilizing sodium thiocyanate offer greater ease of management. The vulcanization mechanism of smithsonite was investigated through FTIR, Zeta potential, and XPS analysis. The findings indicate that the dentate ligand SCN– derived from sodium thiocyanate can undergo chemical adsorption onto the surface of smithsonite through either sulfur (S) or nitrogen (N) elements. The interaction leads to the formation of zinc-thiocyanate anions, which enhance the surface hydrophobicity and expand the mineral collection sites. The overall findings suggest that sodium thiocyanate exhibits promising potential as a highly efficient vulcanization agent for smithsonite, providing valuable insights for the flotation of this mineral.