Reducción de cianuro de agua residual proveniente de una empresa metalúrgica por tratamiento oxidativo con peróxido de hidrógeno

Abstract

In the metallurgical industry, high-level wastes are generated, usually cyanide, which due to their high toxicity cause a negative impact on the environment when they are released. In the present titration work, the degradation of total cyanide contained in wastewater has been taken as a primary objective, by oxidative treatment with 50% hydrogen peroxide, up to the value established by the Ecuadorian environmental regulations TULSMA 2015. In this study a free cyanide oxidation technique with hydrogen peroxide is tested at the laboratory level on a sample of cyanide wastewater from a metallurgical company. An experimental design with three factors is proposed: agitation, retention time and oxidant dosing. The levels of each test factor are evaluated under the following ranges: oxidant / cyanide ratio (2: 1; 5: 1), retention time (2; 4 hours) and stirring (150; 200 rpm). Through an analysis of variance, the effect of each of the aforementioned factors is evaluated, thus obtaining an optimal model to test the effectiveness of the treatment in the degradation of total cyanide. Through this study it was demonstrated that the optimal conditions of degradation of free cyanide and total cyanide are: oxidant / cyanide ratio 6: 1, retention time 240 minutes in terms of agitation, it is decided to work at 175 rpm, reaching a final concentration in cyanide Total according to Ecuadorian environmental regulations. Finally, a technical study is proposed to carry out the process of cyanide degradation in the plant.