Effect of polyaspartic acid as an environmental-friendly depressant on flotation separation of chalcopyrite from arsenopyrite

Abstract

The selection of environmental-friendly and high-efficiency depressants is a major research priority for removing arsenic from copper concentrates. The polyaspartic acid (PASP, (C4H6O3N) n) was used for the selective separation of chalcopyrite from arsenopyrite to explore the depression mechanism of PASP using micro-flotation experiments, contact angle measurements, zeta potential measurements, fourier transform infrared spectroscopy (FT-IR), local electrochemical impedance (LEIS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The flotation results showed that recovery of chalcopyrite reached up 90.18 %, while the recovery of arsenopyrite was only 23.48 %, when the PASP was added. The contact angle measurements and zeta potential measurements showed that PASP selectively adsorbed on the surface of arsenopyrite, but was not adsorbed on the surface of chalcopyrite. The FT-IR tests further confirmed that the adsorption was chemical adsorption. The LEIS tests revealed that the conductivity of arsenopyrite surface increased with the addition of PASP, while chalcopyrite was almost unaffected. The ToF-SIMS analyses illustrated that the arsenopyrite with Fe and As sites was reacted with —NH– in the structure of PASP to form stable complexes. Finally, the mechanism diagram was designed to provide insight into the adsorption mechanism of PASP on the surface of arsenopyrite and its selective inhibition of arsenopyrite.