Research on the distribution of S species in the pressure oxidation leaching process of SrS solution

Abstract

Strontium compounds apply extensively in a variety of domains. Commonly, strontium compounds are made by carbonization of SrS solution. H2S is readily generated in this process. To avoid H2S byproducing, a novel strategy for the pressure oxidation leaching process of SrS solution was used. The overoxidation of sulfides was restrained, and a higher separation efficiency of Sr and S was obtained, which was beneficial for synthesizing other strontium compounds. The effects of the oxidation pH environment, reaction temperature, initial total sulfide concentration and reaction time on the conversion ratio of S species were investigated. The results showed that S0 was preferably generated in a near-neutral, low-temperature and low initial total sulfide concentration oxidation environment. The optimum oxidation conditions were summarized experimentally: 48 mL/L HCl (pH = 7.11), 25 °C reaction temperature, 8.2 g/L initial total sulfide concentration and 60 min reaction time. The optimum conversion ratios were obtained under optimum oxidation conditions as follows: χsulfide 2.3%, χH2S 0.5%, χS0 81.5%, χinter 10.0% and χS - Sr 5.7%. SrCl2 crystal was recovered finally from the leachate. At last, the pressure oxidation mechanism of SrS was discussed.