Experimental and interaction mechanism with novel depressant lysine for the removal of copper ions activation on sphalerite surface

Abstract

Developing highly efficient and selective depressants is an effective measure to solve the susceptibility of sphalerite flotation to copper ion activation. In this study, the depression performance of the novel depressant lysine (Lys) on Cu²⁺-activated sphalerite was investigated, and the removal mechanism was elucidated using contact angle tests, surface adsorption analysis, inductively coupled plasma experiments (ICP), zeta potential measurements, FT-IR analysis, and XPS analysis. The micro-flotation experiment findings investigated that, at pH 9.0 and 30.0 mg/L of Lys, the flotation recovery difference between chalcopyrite and sphalerite was 53.16 %. Lys showed different adsorption behaviors on the surfaces of chalcopyrite and sphalerite, as further demonstrated by contact angle and surface adsorption analysis. Moreover, it was discovered that Lys could effectively inhibit the adsorption of sodium butyl xanthate (NaBX) on the sphalerite surface, leading to selective depression. Based on the outcomes of solution chemistry calculations, ICP experiments, and zeta potential measurements, it also could be concluded that Lys accelerated the dissolution of Cu²⁺ on the sphalerite surface and decreased the negative activation, and Lys ions were found to be the essential constituent of the pulp. FT-IR and XPS analyses confirmed that the RCOO^- a hydrophilic group of Lys, had a coordination reaction with the activating copper ions, which made it a high chemisorption capacity on the sphalerite surface. In addition, the amino group (–NH₂) is indirectly involved in the selective depressant mechanism by interacting with Zn²⁺ ions on the sphalerite surface. Therefore, Lys is a novel and effective sphalerite depressant, offering theoretical and scientific guidance for the flotation separation of chalcopyrite and sphalerite.