Studies on the application of AVR to a cyanide effluent from Riacho Dos Machados ore, Southeastern Brazil

摘要

The primary aim of the treatment of effluents generated in gold processing plants is to remove metallocyanide complexes from slurry and to produce a stream of clarified solution. To the clear solution it is possible then to apply the AVR process (acidification-volatilization-reneutralization) that recycles the cyanide back to the circuit, while the metallic complexes and dissolved metals are precipitated and isolated in a solid concentrate for later disposal or recovery. The chemistry of the process is based on the reactions of alkaline cyanide complexes in sulfuric acid solution that will produce HCN. This work investigates the solubility of an effluent from the cyanidation plant at Riacho dos Machados, Minas Gerais, Brazil. The AVR technology is not indicated for treatment of slurries, since the direct acidification of this fraction increases the acid consumption and the direct precipitation of based methals in the slurries, and that becomen accumulated in the tailings disposal site.