Utilization of PMA-EDTC as a Novel Macromolecular Depressant for Galena in the Flotation Separation of Chalcopyrite

To address the issue of mediocre separation efficiency of depressants in the copper-lead separation process, this article synthesized a macromolecular organic depressant, polymaleic anhydride-ethylenediaminetetraacetic acid (PMA-EDTC), using a polycarboxylic macromolecule as the backbone and also introducing -N-(C=S)-S- as the solidophilic group and employed as a galena depressant. The structure of PMA-EDTC was characterized using Fourier transform infrared (FT-IR). The effect of PMA-EDTC on the floatability of galena and chalcopyrite was investigated through micro-flotation and Contact angle measurements. The experimental results demonstrated that PMA-EDTC exhibited selectivity inhibition towards galena rather than chalcopyrite across a wide pH range. At a dose of 8 mg/L, there was effective separation between galena and chalcopyrite with a separation coefficient of 24.17, effectively altering the floatability of galena while having little impact on the floatability of chalcopyrite. The selective inhibition behavior and adsorption mechanism of PMA-EDTC on galena and chalcopyrite were investigated using FT-IR, Zeta potential, and X-ray photoelectron spectroscopy (XPS). FT-IR and Zeta potential studies indicated that PMA-EDTC formed chemical adsorption on the surface of galena. XPS confirmed the model of chemical adsorption of PMA-EDTC on lead atoms in the galena surface. The results indicate that PMA-EDTC adsorbs on the surface of galena via its -(C=S)-S-group, forming a hydrophilic complex and achieving selective depression of lead and the cleaning flotation of copper.