A new synthetic polymer depressant PADEMA for Cu-Pb separation and its interfacial adsorption mechanism on galena surface

Abstract

In mineral processing, a chemical with hydrophilic groups and mineral-avid groups together might be used as a depressant to depress target minerals. In the present study, a novel polymer depressant poly(acrylamide-2-(dithiocarbamate) ethyl maleamidic acid) (PADEMA) containing amide groups as hydrophilic groups and dithiocarbamate groups as mineral-avid groups, was first designed, synthesized and used to depress galena in the flotation separation from chalcopyrite. Its selective interfacial adsorption mechanism on galena surface was comprehensively investigated by Fourier transform infrared spectroscopy (FT-IR), adsorption capacity tests, contact angle, Atomic Force Microscope (AFM), X-ray photoelectron spectroscopy (XPS) measurements and time-of-flight secondary ion mass spectrometry (ToF-SIMS). These analysis results demonstrated that PADEMA was likely to chemisorb on galena surface by forming a polymer complex via Pb sites on galena surface and the dithiocarbamate groups in PADEMA structure. The micro-flotation separation results indicated that the PADEMA polymer depressant could adsorb on galena surface and render it hydrophilic, thus to improve the separation index during the flotation separation of chalcopyrite and galena.