SULFATE, CALCIUM AND HEAVY-METAL REMOVAL FROM INDUSTRIAL EFFLUENTS USING BARIUM CARBONATE

This paper presents results obtained from reacting barium carbonate with calcium, magnesium and sodium sulphate solutions and sulphate containing industrial and mining effluents. Sulphate removal was very effective when the sulphate ions were associated with calcium. When they were associated with magnesium or sodium the addition of lime aided sulphate removal. The rate of sulphate removal from a calcium sulphate solution was retarded by the presence of magnesium ions. Sulphate removal from a power station cooling water was enhanced by the addition of sulphuric acid. In addition, calcium, magnesium, zinc and cadmium were also removed from solution by barium carbonate. Calcium sulphide could be produced as a by-product of a barium carbonate regeneration process. This sulphide could be used to treat heavy metal containing effluents.