Effective flotation separation of fluorite and barite with the environmentally friendly surfactant caprylhydroxamic acid

The surface properties of fluorite and barite are similar, which results in agent action behaviour that is also similar. it is essential to use a highly selective agent in order to achieve effective separation of the two minerals. In this study, an environmentally friendly surfactant, caprylhydroxamic acid (CHA), was found as an effective collector for flotation separation of fluorite and barite. The results of microflotation experiments show that CHA can achieve effective separation of fluorite and barite with excellent selectivity without the addition of depressants. FT-IR, contact angle measurement, XPS, SEM-EDS measurement and AFM measurement results indicated that the interaction between CHA and fluorite was strong, whereas the adsorption of CHA on barite was weak. CHA is chemically acted on the surface of fluorite mainly through the Ca-O bond. DFT calculations show that the adsorption model of CHA on fluorite surface has lower adsorption energy compared to the adsorption model on barite surface. In the fluorite adsorption model, the electron density surrounding the O atoms is higher, indicating that the CHA adsorption effect is more obvious.