The extraction of antimony from sulfidic wastes has been investigated. Using a special double-zone transpiration reactor, the vapor transport chemistry of antimony sulfide has been established. By varying the sulfur potential in the carrier gas, through the use of an hs/h mixture, it was determined that two transport mechanisms are possible: sb2s3(s,1) = sb2s2(g) + 1/2 s2(g) and sb2s3(s,1) = sb2s3(g). Moreover, if arsenic sulfide vapor is present in the carrier gas, the transport rate of antimony sulfide can be enhanced by several hundred percent owing to the formation of the vapor complex assb3s6(g): 6 sb2s3(s) + as4s6(g) = 4 assb3s6(g). The Gibbs free energies have been determined for the vapor transport reactions. The results have been used to construct vapor pressure-stability diagrams for the sb-s-o system and to identify process conditions for the treatment of sulfidic wastes containing arsenic and antimony.
Proc. 2nd Int'l Symp.-recyc. of Metals & Eng. Mater., Miner. Met. & Mater. Soc., 1990, Pp 39-58