Hydrolytic polymaleic anhydride as a depressant for flotation separation of fine smithsonite from calcite: An experimental and MD study

In this study, the effects of hydrolytic polymaleic anhydride (HPMA) on the flotation separation of fine smithsonite from fine calcite in the Na2S-Pb(II)-xanthate system were investigated. The micro-flotation tests showed that the floatability of fine calcite was significantly decreased after the addition of 40 mg/L of HPMA, while only a slight effect was observed on smithsonite. The inductively coupled plasma optical emission spectrometry (ICP-OES) analysis revealed that the addition of 50 mg/L HPMA dissolved 16.62 mg/L of Ca2+ ions from the calcite surface into the pulp. The analysis of total organic carbon (TOC) and Fourier transform infrared spectroscopy (FTIR) revealed that the HPMA could also chemical adsorption onto the calcite surface. The ultraviolet-visible spectroscopy and zeta potential results indicated that the HPMA blocked the formation of Pb(Ⅱ)-S species on the calcite surface, thus reducing the adsorption of xanthate. The X-ray photoelectron spectroscopy (XPS) analysis further confirmed that the HPMA achieved chemisorption and formed Ca-COOM onto the calcite surface, and the Pb and S contents on the calcite surface decreased significantly after HPMA treatment in the Na2S-Pb(II) system. The molecular dynamics simulation results agreed with the flotation test and measurements analysis results in this work, which explains that HPMA shows stronger adsorption performance on the calcite surface.