sodium sulfide is used as an activator to make the surfaces of intended minerals hydrophobic and sulfide.
in flotation process of oxide minerals,at first,the surface of the intended oxide mineral should be sulfide by sodium sulfide, and the collector should be added to the mixture. adding sodium sulfide,increases the efficiency of the collector and consequently the whole flotation process significantly.
in leather industry:
sodium sulfide is used in leather industry for the sulfitisation of tanning extracts,it is also used during leather processing,as an unhairing agent in the liming operation .
in textile industry:
sodium sulfide is used in textile industry as a bleaching agent,for desulfurising and as a dechlorating agent.
in paper industry:
sodium sulfide is used in craft process in the pulp and paper industry.
it is used in other application including oil recovery, making dyes and detergent.