Abstract
The application of an electric potential difference on the leaching of an auriferous mineral typical of Colombian mining was analyzed in an electroleaching reactor. Electric potentials of 5, 30, and 60 volts were evaluated during 4, 6, and 20 hours. In each of the conditions evaluated, samples of the liquors were taken near the cathode and anode and were analyzed by atomic absorption spectrophotometry. It was observed that there is a direct relation between the applied electric potential and the migrational flow of the gold species to the anode. After the electroleaching process, the used electrodes were analyzed by SEM-EDX, where the presence of gold deposits was detected on the surface of the electrode under all the potential difference conditions applied. Based on the results obtained, a mechanism is proposed to explain the influence on the kinetics of gold cyanidation of the application of an electric potential difference on a column leaching process.
Highlights
INTRODUCTIONGold complexes in an aqueous solution may exist in two oxidation states, aurous (Au+) and auric (Au3+)
LUVER ECHEVERRY VARGAS, NE STOR ROJAS REYESGold complexes in an aqueous solution may exist in two oxidation states, aurous (Au+) and auric (Au3+)
When graphing the variation in gold concentration in accordance to the leaching time in the anode liquor at different voltages, it can be observed that the increase in gold concentration is directly proportional to the increase in the voltage applied. This implies that the higher the electric potential difference applied, the larger the migrational flow of the Au(CN−2 ) species will be to the anode
Summary
Gold complexes in an aqueous solution may exist in two oxidation states, aurous (Au+) and auric (Au3+). The process of ionic species transport in a solution through a mineral porous bed appears under the application of a electric potential difference, and this is achieved by mass flow due to diffusion, migration, and electroosmosis. When an electric potential difference is applied on a mineral bed submerged in an electrolyte, the electric current is transported by the ions present in the solution. When an electric field is established throughout a capillary, excess counterions across the region of the electric double layer adjacent to the particles of the medium move toward the electrode with the opposite charge The movement of these species generates a net tension that is transferred to the molecules of the surrounding fluid through viscous forces, producing a flow in the insterstitial fluid known as the electroosmotic flow (Acar et al, 1995; Valenzuela et al, 2016). This work investigates the influence of an electric potential difference on gold leaching in an auriferous mineral by applying electric potentials of 5, 30, and 60 volts in 4, 6, and 20 hours
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