A nanoscale qualitative study on the role of sodium hydrosulfide in oxidized carrollite flotation

The surface species transformation of oxidized carrollite processing with NaHS and KBX was investigated. Flotation and contact angle tests indicate that the combination of NaHS and KBX takes a better flotation performance than adding NaHS or KBX alone. Thermodynamic analysis, X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) results confirm the stronger chemisorption of KBX occurs on the oxidized carrollite surface with NaHS, which is beneficial to remove the cobalt oxides, thus contributing to the superior floatability. Interestingly, less elemental sulfur was observed on the carrollite surface as the interaction of NaHS and KBX than adding NaHS alone. It suggests that elemental sulfur is not the main contributor to the restored floatability of oxidized carrollite through sulfidisation. This study provided a new perspective to correlate the surface species with xanthate adsorption and oxidized carrollite flotation through determining the various intermediate products.