Tetrazinan-thione collectors for copper oxide mineral: Synthesis and flotation mechanism

Abstract

Abstract Novel tetrazinan-thione compounds including 6-hexyl-1,2,4,5-tetrazinan-3-thione (HTT), 6-propyl-1,2,4,5-tetrazinan-3-thione (PrTT) and 6-phenyl-1,2,4,5-tetrazinan-3-thione (PhTT) were synthesized and originally introduced as collectors for beneficiation of copper oxide mineral. The micro-flotation investigations exhibited that HTT achieved higher malachite recovery with better flotation selectivity against calcite than octyl hydroxamic acid (OHA). The three tetrazinan-thione surfactants significantly improved the hydrophobicity of malachite surfaces as followed: HTT > PhTT > PrTT, matching well with their hydrophobic-hydrophilic index LogP value, as well as their flotation response to malachite. In-situ AFM images clearly presented that HTT firmly covered on malachite surfaces. Zeta potential suggested the chemisorption of malachite towards HTT. FTIR and XPS offered additional evidences that malachite chemisorbed HTT on to its surfaces where the Cu S and Cu N bonds were generated. The heptyl group possesses stronger hydrophobic than the hexyl group, while, HTT exhibited better hydrophobization towards malachite than OHA, which might be attributed to their different bonding mode on malachite surfaces.