Complete sulphate removal from neutralised acidic mine drainage with Complete sulphate removal from neutralised acidic mine drainage with barium carbonate

摘要

The most widespread method used for the treatment of acidic mine drainage (AMD) is neutralisation through thenaddition of lime to the effluent in order to raise the pH. As a result, dissolvedmetals precipitate as metal hydroxidesnwhile partial sulphate removal is achieved. However, further treatment is required in order to reduce the sulphatenconcentration to below 500 mg/ℓ, which is the required concentration for discharge into waterways. The CSIRndeveloped and patented the ABC (alkali-barium-calcium) Desalination process which uses barium salts to furthernreduce the sulphate concentration to acceptable levels with the added advantage that sulphate removal can bencontrolled due to the low solubility of BaSO4. This paper reports on the results of an investigation to demonstratenthe performance of this sulphate removal reaction. Laboratory results that draw attention to the conditionsnrequired for BaSO4 precipitation are presented. A number of parameters, including temperature, initial sulphatenconcentration, barium-to-sulphate molar ratio and different BaCO3 sources were considered. The results werenalso tested and verified on industrial process water. The results clearly demonstrate that the reactor temperature,ninitial sulphate concentration, and molar ratio of barium to sulphate have a positive influence on sulphate removal.