The halide mediated electro-oxidation of ammonia, cyanide, cyanate and thiocyanate in mine/mill waste waters

CIM Bulletin, Vol. 89, No. 1001, 1996

Kazi E. Haque and D.J. MacKinnon, CANMET, MRL, Environmental Laboratory, Ottawa, Ontario K1A 0G1

Ammonia present in a variety of mine/mill waste waters was almost completely oxidized to nitrogen by chloride mediated electro-oxidation. A closed circuit operation of preconcentration of ammonia on a suitable adsorbent (e.g. zeolite or a resin) followed by brine stripping of ammonia and electrolysis of the strip liquor seems to have sound technical, economic and environmental merits. The removal of ammonia, cyanide, cyanate or thiocyanate from a mine/mill waste water (e.g. gold mill), either individually or collectively, is also feasible by chloride mediated electro-oxidation technique. Further R&D investigations are necessary for the development of a closed circuit operation for the removal of ammonia, cyanide and thiocyanate cyanate; and also to obtain technical data for process cost estimates.

Keywords: Ammonia, Chloride electrooxidation, Cyanide, Cyanate, Electro-oxidation, Mediated oxidation, Mineral processing, Thiocyanate, Waste water.