Experimental and simulation study on the flotation separation of smithsonite from dolomite using phosphoryl carboxyl copolymer as a novel depressant

•POCA effectively suppresses dolomite flotation at 5 mg/l, minimally affecting smithsonite.•POCA strongly chelates with dolomite's Ca sites, leading to its higher adsorption capacity than on smithsonite.•POCA pre-adsorption on dolomite increases the steric hindrance and electrostatic repulsion, hindering NaOl adsorption.•A POCA adsorption model for smithsonite-dolomite separation via flotation is devised from experiments. The increasing need for zinc resources and the diminishing supply of sulfide zinc ore reserves have made the extensive application of zinc oxide a significant topic of interest. This study investigates the effects of a newly depressant, phosphorus acyl carboxylic acid copolymer (POCA), in the sodium oleate (NaOL) collector system on the flotation separation of smithsonite from dolomite. Micro-flotation experiments under optimal conditions (pH 9, NaOL 80 mg/L) reveal that adding a minute quantity (5 mg/L) of POCA effectively inhibit dolomite, resulting in a significant recovery rate difference (>80 %). The assessment of POCA adsorption strength on the surface of the mineral, together with the level of ions in solution, provides convincing proof of POCA's dual behavior in selective adsorption and dissolution on the dolomite surface. These discoveries are additionally substantiated by the outcomes of zeta potential and Fourier Transform Infrared Spectroscopy (FTIR) tests. These tests show that the pre-adsorption of POCA diminishes the bond between NaOL and dolomite, while the impact of POCA on smithsonite is negligible. Furthermore, the chemical adsorption between POCA and dolomite has been confirmed through X-ray Photoelectron Spectroscopy (XPS). Atomic Force Microscope (AFM) reveals that POCA has a stronger adsorption-dissolution effect on dolomite than on smithsonite. These findings align with the outcomes of molecular dynamics and Density functional theory (DFT) simulations.