Improved flotation of molybdenite from talc using a selective reagent scheme

Abstract

Talc is one of the most problematic gangue minerals for molybdenite flotation owing to its strong natural hydrophobicity. In this work, pullulan polysaccharide (PU) was evaluated as a potential depressant in the flotation separation of molybdenite from talc. Bench flotation tests of single mineral samples and multi-mineral samples were carried out to evaluate the performance of PU in flotation. And the results show that under the preferable reagent scheme of 40 mg/L PU, 160 mg/L butyl xanthate (BX) and 25 μL/L MIBC, molybdenite can be effectively separated from talc over a wide pH range (from 2.0 to 8.0). Furthermore, FTIR and XPS analyses demonstrate that BX can desorb the pre-adsorbed PU on the surface of the molybdenite by competitive adsorption, but has only a slight effect on the PU adsorbed on surface of the talc. The results also confirm that PU has a strong and stable adsorption on the surfaces of talc and molybdenite, whereas BX adsorbs more strongly on the surface of molybdenite. Hence, the reagent scheme of PU + BX, with biodegradability, low toxicity, low cost and synergistic selectivity, has great potential for industrial application in the flotation separation of molybdenite from talc.