Combined inhibitor for flotation separation of lead-sulfur sulfide ore and application thereof

The invention discloses a combined inhibitor for flotation separation of lead-sulfur sulfide ore and application thereof. The combined inhibitor comprises L-cysteine and sodium poly(naphthaleneformaldehyde)sulfonate, and is used for flotation separation of galena and pyrite. According to the invention, raw ore is ground to obtain to-be-floated ore pulp; zinc sulfate, ethyl xanthate and 2# oil are sequentially added into the ore pulp for lead-sulfur bulk flotation operation, so lead-sulfur bulk concentrate is obtained; L-cysteine and sodium poly(naphthaleneformaldehyde)sulfonatete are added into the lead-sulfur bulk concentrate to serve as the combined inhibitor of pyrite, and lead-sulfur separation flotation operation is conducted, so lead concentrate and sulfur concentrate are obtained; and the combined inhibitor has a relatively strong selective inhibition effect on pyrite, effectively realizes flotation separation of galena and pyrite, has the excellent characteristics of low dosage, good water solubility,