versão On-line ISSN 0718-0764
JUAREZ, Julio C; RIVERA, Isauro; PATINO, Francisco e REYES, María I. Temperature and Concentration Effect of Thiosulfates on the Dissolution Rate of Silver contained in Mining Waste using S2O32--O2-Zn2+ Solutions. Inf. tecnol. [online]. 2012, vol.23, n.4, pp. 133-138. ISSN 0718-0764. http://dx.doi.org/10.4067/S0718-07642012000400015.
The effect of the temperature and thiosulfate concentration on the dissolution rate of silver contained in mining wastes, using the system S2O32--O2-Zn2+ was studied. In the State of Hidalgo in México, thousands of tons of waste mining having around 71 grams of silver per ton of waste have been accumulated over the years. This is the main reason that motivates this study. It was observed that the temperature drastically affects the leaching rate of the silver showing an activation energy Ea= 55.85 kJ mol-1, implying that the dissolution reaction is controlled by the chemical reaction. The thiosulfate concentration shows a considerable influence on the precious metal dissolution rate. The maximum silver dissolution was found to be approximately 97% at 45 °C and 40 gL-1 of [S2O32-]. It is concluded that the process studied represents a good alternative when compared to other processes such as the toxic cyanidation reaction.
Palavras-chave : lixiviación; desechos mineros; plata; tiosulfatos; leaching; tailings; silver; thiosulfates.