Abstract

ROMERO BONILLA, HUGO; GUERRERO RODRIGUEZ, RICARDO  and  MORA MOROCHO, MARÍA. Effect of the speed of the agitation on the kinetics of the leaching with thiourea of gold-floated minerals. Ing. Desarro. [online]. 2020, vol.38, n.1, pp.243-258.  Epub June 15, 2021. ISSN 0122-3461.  https://doi.org/10.14482/inde.38.1.531.3.

In this work, the effect of the agitation speed on the thiourea kinetics with thiourea of gold-floated minerals, the concentration of thiourea (TU) that achieved the greatest recovery of gold from its floated concentrates compared with cyanide was determined, along with the kinetic model that controls leaching with thiourea. For this, a "Suction tube" type Baffled reactor is used with mechanical agitation by means of a vane type impeller. The parameters analyzed were: percentage of solids (15%); TU concentration (1, 3, 6, 9, 12 g / L); stirring speed (420, 490, 560, 700 rpm); reaction time (4 hours); effective reactor capacity (27.1 L). An atomic absorption spec-trophotometer is estimated to determine the gold concentration. It was determined that the thiourea concentration of 9 g / L was the one that produced the best gold recovery results. The thiourea leaching process adapts to the kinetic diffusion model through the ash layer as a controlling stage. Thiourea, as a leaching agent of the Au concentrate, has a lower percentage (1.74% less) of recovery of this metal than with cyanide during the leaching process at 240 minutes of stirring at a stirring speed of 700 rpm.

Keywords : concentrate; green chemistry; gold; kinetics; leaching; thiourea.

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