Flotation separation of chalcopyrite from talc using carboxylated chitosan as a depressant and insight into its selective adsorption mechanism

A novel depressant, CCS, has been developed for the selective inhibition of talc minerals. • Efficient flotation separation of chalcopyrite from talc can be achieved under natural pH conditions. • The adsorption of CCS onto the talc surface is predominantly physical in nature. • This work offers a green and efficient strategy for the comprehensive recovery of copper from talc-bearing ores. In the flotation of sulfide ores, easily floatable gangue minerals such as talc can adversely affect flotation efficiency. Therefore, effective depressants are commonly employed to selectively inhibit talc flotation. This study investigates the application of carboxylated chitosan (CCS), an environmentally friendly and non-toxic talc depressant, in the flotation separation of chalcopyrite and talc. The flotation test results show that under neutral pH conditions, with CCS as a depressant and butyl xanthate as a collector, efficient separation of chalcopyrite and talc can be achieved. Adsorption capacity measurements, energy-dispersive X-ray spectroscopy (EDS), and Fourier-transform infrared (FTIR) spectroscopy analyses indicated that CCS preferentially adsorbs onto the talc surface rather than onto the chalcopyrite surface. X-ray photoelectron spectroscopy (XPS) analysis revealed that the interaction between CCS and the talc surface is primarily physical adsorption. Density functional theory (DFT) calculations further confirmed that CCS exhibits weaker adsorption affinity for the chalcopyrite surface, thereby facilitating the subsequent adsorption of butyl xanthate (BX) onto chalcopyrite and enabling its flotation separation from talc. Collectively, this study provides theoretical guidance for the use of CCS as an effective talc depressant in the flotation separation of chalcopyrite and talc. Download: Download high-res image (188KB) Download: Download full-size image