Effect of Ammonium Carbamate on Catalytic Sulfidation and Flotation of Azurite

Abstract

In this study, the effects of CH6N2O2 and Na2S·9H2O on azurite catalytic sulfidation were studied. The catalytic sulfidation of CH6N2O2 and Na2S·9H2O achieved a satisfactory sulfidation flotation of azurite. The recovery rate of catalytic sulfidation azurite was 82.51%. The Cu(II) species on the pure azurite surface were reduced to Cu(I) species, and the S2− was oxidized to Sn2− or S2− species, forming a highly crystalline CuS2. The analyses revealed that the rougher the azurite surface, the higher the atomic concentration of S and the more CuS2 species formed, generating hydrophobic surfaces and promoting the flotation of azurite. The dissociative adsorption of H2O molecules on the (0 1 1) surface of azurite hindered further adsorption of HS− species on the (0 1 1) surface of azurite. The adsorption energy of HS− species on the (0 1 1) surface of azurite was more negative with NH3, indicating that the NH3 enhanced the adsorption of HS− species. In addition, the chemical bond strength of Cu-S formed through catalytic sulfidation of azurite was stronger than the chemical bond strength of Cu-S of direct sulfidation. The enhancement of between S and Cu bond greatly improved the stability of sulfide layers after catalytic sulfidation.

Keywords: azurite, roughness, chemical shift, catalytic sulfidation, DFT