Reverse flotation separation of calcite/dolomite from hemimorphite based on their surface sulphophile and oxyphile affinity differences

This study attempts to selectively inhibit hemimorphite flotation using sodium sulphide and uncover the mechanisms behind it. With the use of a fatty acid collector, the flotation test results showed that sodium sulphide had a strong inhibition performance on hemimorphite flotation while having no adverse impact on calcite and dolomite flotation, which were consistent with the contact angle measurement results. According to the results of attenuated total reflectance-Fourier transform infrared spectroscopy and adsorption proportion measurement of sodium oleate, sodium sulphide can inhibit sodium oleate binding on hemimorphite surfaces while having no effect on calcite and dolomite surfaces. The sulphide species exhibited an extremely high binding affinity for the hemimorphite surface but not for the surfaces of the calcium/magnesium-bearing gangue minerals, as demonstrated by the X-ray photoelectron spectroscopy measurements. Because of the strong sulphophile affinity of zinc, when the sodium sulphide concentration was sufficiently high, an interface boundary layer of a liquid solution with the remaining sulphide species formed on the hemimorphite surface, preventing sodium oleate from binding on the hemimorphite surfaces and thus selectively inhibiting the hemimorphite flotation.