Arsenic Removal From Gold-Mine Waste Waters: Basic Chemistry of the Lime Addition Method

CIM Bulletin, Vol. 69, No. 773, 1976

D. Laguitton,IBM Research Laboratory, San Jose, California

The basic chemistry of arsenic related to its dissolution and subsequent precipitation in gold-mine waste waters is discussed. The lime addition methods provides the most economic treatment of arsenical slurries, but requires a careful control of the oxidation of As1" into Asv, of the pH (>12) and the filtration of the precipitate. If arsenic levels below 0.5 mg/l are required, a modification of the method by phosphate addition must be considered.
Keywords: Environmental control, Arsenic, Gold milling, Waste waters, Lime additions, Water pollution.