Abstract: Gold exists in the form of free fine gold and gold-wrapped sulfide in mercury smelting slag with gold bearing of 1.85 g/t.Research on recovering gold by flotation from the secondary resources was carried out.The research results showed that under grinding fineness of -0.074 mm 80%，gold concentrate with gold grade of 28.65 g/t，and recovery of 68.45% was obtained by the flow sheet of one-roughing，two-cleaning，three-scavenging and middles back to the process in order.The main reasons resulting in low gold recovery are that gold occurs in ultra-fine particles or was wrapped by carbonates，limonite，quartz and silicate.

Key words: Gold-bearing mercury sinelting slay, Freefine gold,Gold-wrapped sulfide, Secondary resources