Leaching kinetics in cyanide media of Ag contained in the industrial mining-metallurgical wastes in the state of Hidalgo, Mexico

The leaching kinetics in cyanide media of the silver contained in the Dos Carlos waste tailings at the City of Pachuca de Soto, Hidalgo State, Mexico were carried out. The used material contained the following chemical composition: 56 × 10-6 of Ag, 0.6 × 10−6 of Au and 70.43% (by weight) of SiO2; 7.032% (by weight) of Al2O3; 2.69% (by weight) of Fe; 0.46% (by weight) of Mn; 3.98% (by weight) of K2O; 3.34% (by weight) of CaO; 2.50% (by weight) of Na2O; 0.04% (by weight) of Zn; 0.026% (by weight) of Pb. The mineralogical phases present were the following: Silica, albite, argentite, berlinite, orthoclase, potassium jarosite, and natrojarosite. In the leaching kinetics in cyanide media, and under the studied conditions, the effect of the CN− concentration on the reaction rate has no effect on the whole process of alkaline cyanidation, of which the reaction order is n ≈ 0. Temperature has an effect on the cyanidation rate of the reaction, with an activation energy of 47.9 KJ/mol. At the same time, when the particle size decreases there is an increase in the reaction rate, which is inversely proportional to the particle diameter; when increasing the NaOH concentration there is an increase in the reaction rate Kexp, with a reaction order (n) of 0.215 under the studied ranges.