Arsenic removal from gold processing waste waters: the potential ineffectiveness of lime

CIM Bulletin, Vol. 75, No. 840, 1982

ROBERT G. ROBINS' School of Chemical Engineering & Industrial Chemistry, The University of New South Wales, KAZUTERU TOZAWA, Institute of Mineral Dressing & Metallurgy Tohoku University, Sendai, Japan

The stability of calcium arsenate is discussed in relation to the possible misuse of lime in the treatment of gold processing waste waters. Stability diagrams have been derived and experimental results cited to show that calcium arsenate has a higher solubility in neutral to alkaline solution than has previously been recognized and this solubility is further enhanced by the presence of carbon dioxide, bicarbonate or carbonate.
Keywords: Mineral processing, Gold processing, Arsenic removal, Lime, Calcium arsenate.