Evaluation of the difference in adsorption of sodium alginate as an efficient and non-toxic arsenopyrite depressant on the surface of arsenopyrite and chalcopyrite

Abstract

In this study, sodium alginate (SA) was used as a selective depressant, combined with potassium permanganate oxidizing pretreatment, which will benefit the separation of chalcopyrite and arsenopyrite. Flotation experiments were conducted with chalcopyrite and arsenopyrite after treatment with SA and/or potassium permanganate, and the possible complexes formed by SA on the mineral surface were theoretically analyzed. SA was more easily adsorbed on the arsenopyrite surface after potassium permanganate pretreatment. The maximum depressant effect of arsenopyrite was observed following treatment with 62.5 mg/L of potassium permanganate and 1000 mg/L of SA with flotation at pH 11. Fourier-transform infrared spectroscopy and X-ray photoelectron spectroscopy indicated that the adsorption of SA on the chalcopyrite and arsenopyrite surfaces was dominated by chemisorption. Theoretical analyses confirmed that the adsorption strength of SA on the arsenopyrite surface was higher than that on chalcopyrite. Furthermore, the intermolecular interactions between SA and the possible complexes formed were investigated using interaction region indicator function tools. The results of this investigation revealed that SA adsorption on chalcopyrite and arsenopyrite surfaces is controlled by partial covalent hydrogen bonds and other weak interactions. Therefore, SA can be used as a promising green depressant for the separation of arsenopyrite during chalcopyrite flotation.