Destruction of cyanide by ozone in two gas-liquid contacting systems

F.R. Carrillo-Pedroza*, M.J. Soria-Aguilar

Facultad de Metalurgia, Universidad Autónoma de Coahuila, Carr. 57 Km 5, CP 25710, Monclova, Coahuila, México

Received Received 14 May 2001; accepted 10 July 2001


The treatment of aqueous effluents resulting from cyanidation process is one of the main problems in the gold mining industry. Different methods are used for cyanide destruction or cyanide regeneration. Ozone is an alternative that presents the advantage of the removal of cyanide of cyanidation tailings. The reactions of oxidation of cyanide by ozone were studied in aqueous solutions using a bubble column and a mechanically-stirred reactor. These reactors were operated at different conditions of ozone dosage rate, gas-flow rate and cyanide concentrations. The rate of the oxidation of cyanide by ozone can be described by an equation, which is of first order with respect to ozone and independent on the cyanide concentration. The reaction of ozone with cyanide occurs by oxidation of one mole of cyanide by one mole of ozone. This work shows that the rate of oxidation of cyanide by ozone is independent of the type of reactor.

Keywords: Cyanidation effluents; Ozone; Cyanide; Kinetics

* Corresponding author
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