AN EXPERIMENTAL STUDY OF STIBNITE SOLUBILITY IN GASEOUS HYDROGEN SULPHIDE FROM 200 TO 320°C

Abstract

The solubility of stibnite in gaseous hydrogen sulphide was investigated experimentally in the systems Sb2S3-S-H2S and Sb2S3-H2S at temperatures between 200 and 320°C (pressures of up to 200 bars). The concentrations obtained are several orders of magnitude higher than those calculated for H2S-free systems and display a prograde dependence on temperature in the range of 200 to 290°C. Concentrations of Sb2S3 are relatively constant at temperatures ranging from 290 to 320°C with a proposed solubility maximum at 300°C. In order to be able to describe stibnite solubility in the gas phase a simple solvation model was used, namely: Sb2S3cryst. + H2Sgas = Sb2S3 . (H2S)gas.Equilibrium constant for this solvation reaction varied from 10-6.76 to 10-5.77 over the temperature range from 200 to 320°C.