Adsorption and depression mechanism of an eco-friendly depressant PCA onto chalcopyrite and pyrite for the efficiency flotation separation

At present, it is still a difficulty to separate chalcopyrite from pyrite due to the similar electrochemical properties of the two minerals, which would dilute the grade of copper concentrates and affect the follow process. In this paper, polypropylene carboxylic acid (PCA) was used as an environmentally friendly depressant to efficiently separate pyrite from chalcopyrite, and the separation performance was evaluated by micro-flotation experiments. The results of the flotation experiments showed that PCA could selectively depress the flotation of pyrite rather than that of chalcopyrite when using SBX as the collector, and the optimum separation performance was realized at the reagent scheme of 60 mg/L PCA and 15 mg/L SBX when pH was 8.16. Meanwhile, the selective depression mechanism of PCA on the two minerals was also investigated via a series of surface analyses. The analyzed results indicated that PCA could be chemisorbed on pyrite surface via the Fe sites and impede the further adsorption of SBX, which would intensively enhance the hydrophilicity of pyrite and make it sink into the tailing products even in the presence of SBX. However, the adsorption of PCA on chalcopyrite surface was very weak and SBX could still be chemisorbed on chalcopyrite surface even the chalcopyrite was pre-conditioned with PCA. Therefore, PCA could be selected as the potential depressant for the efficient separation of chalcopyrite from pyrite.