A novel efficient activator 2-mercaptopyridine in azurite flotation: Flotation performance and Reaction mechanism

Azurite is an important oxidized copper mineral, and the traditional sulfidation-xanthate flotation process still fails to achieve ideal results. Organic chelating reagents containing donor atoms such as N, S, and O have demonstrated excellent performance in mineral flotation and copper corrosion inhibitor research. However, such reagents have rarely been applied in azurite flotation studies. This study introduces a novel N/S – containing activator, 2-mercaptopyridine (2-MP), for azurite activation, and investigates its modification mechanism and flotation effects on azurite. Micro-flotation tests show that 2-MP significantly improves azurite's flotation performance. The flotation recovery of azurite in the 2-MP-potassium butyl xanthate system increased substantially from 37.54% to 97.23%. Theoretical studies reveal that 2-MP activates the azurite surface to form a dense product layer containing S/N elements. This S/N – enriched hydrophobic layer facilitates effective xanthate adsorption, thereby enhancing flotation recovery. The activation mechanism is elucidated as follows: The N/S atoms in 2-MP interact with copper sites on the azurite surface, forming 2-MP-Cu complexes containing S-Cu and N-Cu bonds that adsorb onto the mineral surface, exposing more copper sites. Simultaneously, Cu(II) is reduced to highly active Cu(I), providing a fresh active surface that greatly promotes xanthate adsorption while improving the mineral's hydrophobicity and floatability. This work reveals the surface modification mechanism of the bidentate organic chelating reagent 2-MP on azurite, offering a new approach for the efficient utilization of oxidized copper mineral resources.