Separation of molybdenite from chalcopyrite with thiolactic acid depressant: Flotation behavior and mechanism
(1. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Engineering Research Center of Ministry of Education for Carbon Emission Reduction in Metal Resource Exploitation and Utilization, Central South University, Changsha 410083, China)
2. Engineering Research Center of Ministry of Education for Carbon Emission Reduction in Metal Resource Exploitation and Utilization, Central South University, Changsha 410083, China)
Abstract: The separation of molybdenite and chalcopyrite is a major challenge because of their similar floatability. It is essential to discover a depressant for selectively inhibiting chalcopyrite in a profitable and sustainable way. A novel chalcopyrite depressant, thiolactic acid (TLA), was proposed. The flotation behaviors were studied through micro-flotation and artificial mixed minerals flotation. Micro-flotation experiments indicated that thiolactic acid could significantly suppress chalcopyrite recovery from 81% to 9.7%, along with molybdenite recovery always more than 71%. Artificial mixed minerals flotation experiments showed a distinct separation behavior between chalcopyrite and molybdenite with an optimal Gaudin’s selectivity index of 12.9. The reactivity mechanism of TLA on molybdenite and chalcopyrite surfaces was determined by FT-IR, XPS, and AFM with a possible adsorption model presented. The results revealed that —SH and —COOH groups of TLA preferentially occupied the active copper site on chalcopyrite surface, inhibiting subsequent sodium n-butyl xanthate chemisorption.
Key words: thiolactic acid; chalcopyrite; chalcopyrite depressant; Cu-Mo separation