Selective depression of galena by tamarind seed gum during chalcopyrite flotation

Abstract

The similar flotation properties of chalcopyrite and galena pose significant challenges for their flotation separation. To address this, tamarind seed gum (TSG) was evaluated as an galena depressant with butyl xanthate (BX) as the collector in the flotation separation of chalcopyrite and galena. The depression mechanism of TSG on galena was investigated through flotation tests, contact angle measurements, zeta potential measurements, X-ray photoelectron spectroscopy (XPS) analyses, inductively coupled plasma optical emission spectrometer (ICP-OES) tests, Atomic force microscopy (AFM) tests and density functional theory (DFT) calculations. The flotation tests demonstrated that TSG had strong depression effect on galena under neutral condition. However, it slightly affected chalcopyrite flotation. The adsorption of TSG on the galena surface was confirmed through contact angle measurements, zeta potential measurements, XPS analyses. The ICP-OES tests revealed that TSG impeded the dissolution of Pb²⁺ and improved its hydrophilicity. AFM tests demonstrated a pronounced augmentation in the adsorption affinity of TSG towards the galena surface as opposed to chalcopyrite, consequently hindering subsequent collector attachment onto galena. Density Functional Theory (DFT) calculations indicated the active hydroxyl groups in the polysaccharide structure of TSG have a strong interaction with lead hydroxide of galena surface, while exhibiting very low affinity for the lead hydroxide of galena surface. This study provides a theoretical basis for using TSG as an galena depressant in the flotation separation of galena from chalcopyrite.