Abstract: To elucidate the enhancement mechanism of staged sulfidation process on the flotation behavior of azurite and
the growth law of surface sulfidation products,this study systematically investigated the effect of staged sulfidation on the recovery
of azurite through pure mineral flotation tests. The evolution of surface micromorphology and chemical states was analyzed
using transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The flotation behavior study
showed that under optimal single-stage conditions (Na2S of 160 mg/ L,butyl xanthate of 160 mg/ L,sulfidation time of 1 min,
pH=9),the recovery was 75. 59%. Maintaining the total reagent dosage constant,the highest cumulative recovery of 97. 15%
was achieved with a four-stage sulfidation process and a reagent mass ratio of 4∶3∶3∶2. Surface analysis indicated that sulfidation
led to the formation of a multiphase composite sulfide film (comprising CuS,Cu2S,and CuSx ) with nano-sized irregular
flaky morphology on the azurite surface,where sulfur was preferentially enriched at particle edges and protrusions. XPS analysis
further revealed that compared to single-stage sulfidation,the relative surface content of S and Cu increased after four-stage
treatment,with the proportions of stable sulfide (S2- ) and reduced copper (Cu(Ⅰ)) significantly enhanced,while the proportion
of oxidized sulfur species (SO2- n ) decreased. This confirms that staged sulfidation promotes the formation and growth of
more stable and compact sulfide phases through a "gradual" reaction mechanism,thereby significantly improving the floatability
of azurite.