Destruction of cyanide waste solutions using chlorine dioxide, ozone and titania sol

Increasingly, there are severe environmental controls in the mining industry. Because of lack of technological advances, waste management practices are severely limited. Most of the wastes in the milling industrial effluents are known to contain cyanides and it is recognized that after extraction and recovery of precious metals, substantial amounts of cyanide are delivered to tailings ponds. The toxicity of cyanide creates serious environmental problems. In this paper we describe several methods for the treatment of cyanide solutions. These include: (1) cyanide destruction by oxidation with chlorine dioxide (ClO2) in a Gas-Sparged Hydrocyclone (GSH) reactor; (2) destruction of cyanide by ozone (O3) using a stirred batch reactor, and finally, (3) the photolysis of cyanide with UV light in presence of titania sol. In all cases excellent performance were observed as measured by the extent and of the destruction.