Principles and Economic Considerations of Electrochemical Treatment of Cyanide-Laden Wastewater

The mining industry is a global economic driver, that produces the metals and minerals required to sustain our current technological advancements. It is also however, a water intensive industry, that uses a third of Canada's fresh annual water resources. The increased mining activity requires significant waste and wastewater treatment of the contaminated water. The gold mining industry in particular is integral to the production of electronics, copper, and the solar panels that are required for the long-term growth of the renewable energy sector. Significant demand in recent years has lead the gold mining industry to consume 20% of the annual production of cyanide, which is used as a leaching reagent. The health and environmental risk posed by the wide spread use of cyanide has raised public concern, and as a result ever more stringent wastewater discharge requirements are being implemented. The current conventional method of treating cyanide requires a large amount of real estate, leads to persistent toxicity, and prevents mine operators from successfully meeting land reclamation requirements. Electrochemical oxidation and coagulation of cyanide offers an alternative wastewater treatment method that requires less real estate, is amenable to automation, and capable of meeting new stringent requirements. This paper presents the economic framework needed to assess the technical and economic validity of employing electrochemical treatment methods of cyanide-laden wastewater.