Corrosion activation by ammonium fluoride enhances the separation of chrysocolla and quartz by sulfidation flotation

Abstract

In this study, the effects of ammonium fluoride (NH4F) on chrysocolla corrosion activation were investigated. Fluoride ions corroded the surface of chrysocolla and exposed more active copper particles to facilitate the catalytic sulfidation of ammonium, which increased the flotation recovery by 59.14 %. After treatment with a solution of NH4F and Na2S·9H2O, atomic force microscopy (AFM) imaging revealed that the surface of chrysocolla was rougher than that treated with the Na2S·9H2O solution. This indicated that the F ions reacted with Al and Si ions on the mineral surface and corroded the mineral surface, and NH3 reacted with Cu ions to form Cu(NH3)i2+ (i = 1, 2, 3, 4) on the mineral surface and became adsorbed to the mineral surface. Time-of-flight secondary-ion mass spectrometry (ToF-SIMS) surface analysis and X-ray photoelectron spectroscopy (XPS) analysis revealed that the −Al−O−Si− structure of the chrysocolla surface was greatly damaged by NH4F, and the formed Cu(NH3)+ promoted the formation of CuS2 films through catalytic sulfidation to obtain chrysocolla with surface hydrophobicity. Fourier transform infrared (FTIR) spectroscopy analysis and adsorption capacity measurements showed that xanthate has strong adsorption capacity on the activated hydrophobic surface of chrysocolla. All the results showed that NH4F contributes to the formation of more hydrophobic CuS2 films on the chrysocolla surface. The treatment with NH4F resulted in a satisfactory separation of chrysocolla and quartz by sulfidation flotation.