Flotation separation of fluorite from calcite using bis hydroxamic acid collector

•Novel collector (OBHA) was introduced in fluorite and calcite flotation separation.•OBHA exhibited strong collecting ability and good selectivity.•OBHA can achieve the flotation separation of fluorite from calcite. The efficient separation of fluorite and calcite is a challenging task in the field of mineral processing because of their similar chemical and physical properties. In this research, octylamino-bis-(butanohydroxamic acid) (OBHA) was introduced as collector into a flotation system comprising fluorite and calcite, and the separation of fluorite and calcite was realized in the absence of any depressants. ζ potential, FTIR, XPS measurements and DFT calculations were performed to investigate the mechanism for the selective adsorption of OBHA. The results indicate that the hydroxamic acid group of OBHA account for the adsorption process, and the adsorption of the hydroxamic acid group on fluorite was much stronger than that on calcite surface.