Novel technology for hydrogen sulfide purification via the slurry prepared from roasted vanadium steel slag

Abstract

Roasted vanadium-bearing steel (V-S) slag was used to prepare absorption slurry to purify H2S offgas, and the technical parameters and mechanism for the H2S purification were investigated in this study. The roasted V-S slag had a relatively high alkalinity and abundant higher-valence metal oxides, and it exhibited a relatively high desulfurisation efficiency and sulfur capacity. When the pH of the absorption slurry maintained a natural variation, the desulfurisation rate in the absorption system was almost 100% within 100 min, then gradually decreased from 96.9% at 120 min to 77.2% at 260 min. O2 could moderately restore the oxidation performance of the absorption slurry, and the O2 content in the inlet gas was not less than 0.5%. The molecular H2S diffused from a gas to liquid phase. HS− was the main form of soluble sulfide under alkaline condition, and it might be oxidised to sulfur-containing products by the dissolved metal ions or oxygen in the aqueous solution. Based on the principles of physical chemistry and the results obtained in this study, a pathway of the H2S catalytic purification via the absorption slurry of roasted V-S slag was proposed, and potential chemical reactions during the desulfurisation process were also suggested to expound on the process of H2S catalytic oxidation.