Abstract: As the important part of copper ore resources，improving development and utilization technologies of copper oxide minerals is of great significance for efficient and comprehensive recovery of copper resources. Azurite is important copper oxide mineral，while the floatability is poor，usually by sulfide flotation to recover it. The effects of ammonium sulfate on the sulfidization flotation of azurite has been investigated using monomineral flotation experiments. The activation mechanism of ammonium sulfate on azurite sulfidization flotation was studied by the analysis of the adsorption energy calculation of the reagents on the mineral surface，the changes of elements type and contents on mineral surfaces both before and after interaction with buthy xanthate. The results showed that the recovery of azurite was increased to 60.03% with the 200 mg/L ammonium sulfate from 44.15% of no ammonium sulfate. After the addition of ammonium sulfate，the relative contents of copper and sulfur on mineral surface were increased，and the relative contents of carbon and oxygen were reduced，the sulfidization and hydrophobicity of mineral surface were improved，facilitating the adsorption of butyl xanthate. The calculation results obtained from Material Studio indicted that the adsorption energy of HS-ions and C4H9OCSS-ions on azurite surface decreased after the adding of ammonium sulfate，the adsorption stability of butyl xanthate and sodium sulfide on the azurite surface was increased，which had an activation effect on the sulfidization flotation of azurite.

Key words: Azurite, Sulfidization flotation, Ammonium sulfate, Activation, Gene mechanism