Effect of DL-cysteine on the flotation behavior of jamesonite and marmatite: Experimental and DFT studies

A novel flotation depressant with selective adsorption properties based on orbital matching was used to replace cyanide for the flotation separation of jamesonite and marmatite. The presence of characteristic groups, such as the sulfhydryl and amino groups, enhanced the adsorption of DL-cysteine on the metal ions (Zn2+ and Fe2+) on marmatite surface. The adsorption of DL-cysteine on the marmatite surface significantly enhanced the surface hydrophilicity and decreased the flotation recovery. [Display omitted] •DL-cysteine is a potential green depressant for marmatite flotation.•DL selectively depressants marmatite but has little effect on jamesonite floatability.•The adsorption between DL and marmatite hinders DDTC adsorption.•Coordination theory analysis confirmed the complexation between DL and Fe2+/Zn2+. Flotation is an effective separation technique for removing marmatite, a harmful impurity, from jamesonite. In this study, DL-cysteine (DL) was used as an eco-friendly flotation agent for the targeted separation of jamesonite from marmatite. Micro-flotation experiments, zeta potential measurement, Fourier transform infrared, and X-ray photoelectron spectroscopies show that DL can combine with metal ions on the surface of marmatite through chemical complexation, thereby selectively hindering the flotation of marmatite. The competitive adsorption of DL and sodium diethyldithiocarbamate on marmatite surface is the main factor leading to the change in marmatite floatability. The flotation coordination theory confirms that Fe2+ is the main active site on marmatite surface. π-back-bonding and σ-bonding are the main driving forces for the adsorption of DL on marmatite surface. Importantly, DL can be produced using animal hair as a raw material. It is, thus, a low-cost material with good environmental compatibility and high selectivity and a potential green depressant for marmatite flotation.