Thermodynamic and Kinetic Study for Silver Recovery by Electrocoagulation Process

• Published in: Mining, metallurgy & exploration Vol. 39; no. 1; pp. 153 - 159
• Main Authors: Montaño, Erick, Vázquez, Víctor, Valenzuela, Jesús L., Tiburcio, Guillermo, Parga, José, Valenzuela, Alejandro, Encinas, Martin
• Format: Journal Article
• Language: English
• Published: Cham Springer International Publishing 01-02-2022
• Subjects: Engineering; Materials Engineering; Metallic Materials; Mineral Resources; Review; Silver; Electrocoagulation; Adsorption; Cyanidation
• ISSN: 2524-3462; 2524-3470
• DOI: 10.1007/s42461-021-00509-5

Merrill-Crowe is the primary process used for the concentration and purification of silver in a cyanide solution. The Langmuir Adsorption model for silver recovery in a cyanide solution was used for the study. The maximum adsorption capacity was 6.19 mmol/g for silver. This model properly adjusts the experimental results of the adsorption equilibrium with high correlation coefficients, which also favors the formation of a single layer of molecules adsorbed for the silver in the electrocoagulation-generated species. The thermodynamic parameters ΔG, ΔH, and ΔS were estimated, and it was found that the adsorption process is exothermic and spontaneous. For the kinetic study, the Lagergren second-order equation was used to study the adsorption speed. To characterize the solids coming from the electrocoagulation, X-ray diffraction (XRD), and scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDX) were used; the results of this study suggest that silver is present in aluminite, hydroniumjarosite, and alunogen.