Treatment of Mine Water for Sulphate and Metal Removal Using Barium Sulphide

• Published in: Mine water and the environment 2004-12, Vol.23 (4), p.195-203
• Main Authors: Maree, J. P., Hlabela, P., Nengovhela, R., Geldenhuys, A. J., Mbhele, N., Nevhulaudzi, T., Waanders, F. B.
• Format: Article
• Language: English
• Subjects: Acid mine drainage; Alkalinity; Barite; Barium; Barium sulfate; Barium sulfides; Bicarbonates; Calcium; Calcium carbonate; Carbon dioxide; Chemical precipitation; Crystallization; Groundwater pollution; Gypsum; Heavy metals; Hydrogen sulfide; Hydroxides; Iron; Metals; Mine drainage; Mine waters; Precipitation; Removal; Sulfates; Sulfur; Sulphides; Sulphur; Water treatment
• ISSN: 1025-9112; 1616-1068
• DOI: 10.1007/s10230-004-0062-y

The integrated barium sulphide process consists of: preliminary treatment with lime, sulphate precipitation as barium sulphate, H2S-stripping, crystallization of CaCO3, and recovery of barium sulphide. Our tests showed that during lime pre-treatment, sulphate was lowered from 2 800 mg/L to 1 250 mg/L by gypsum crystallization; metals were precipitated as hydroxides. The BaS treatment then lowered sulphate to less than 200 mg/L. Sulphide was lowered from 333 to less than 10 mg/L (as S) in the stripping stage, using CO2 gas for stripping. The stripped H2S-gas was contacted with Fe (III)-solution and converted quantitatively to elemental sulphur. The alkalinity of the calcium bicarbonate-rich water was reduced from 1 000 to 110 mg/L (as CaCO3) after CO2-stripping with air due to CaCO3 precipitation. Fe (II), after sulphur production, was re-oxidized to Fe (III) using an electrolytic step. The running cost of the BaS process is R2.12/m3 (US$1 = SAR6.5) for the removal of 2 g/L of sulphate.