Estudio de la oxidación de un mineral sulfurado aurífero refractario en medio acuoso para incrementar la disolución de oro en el proceso de cianuración

Abstract

In the present work, three oxidative methods were evaluated to improve the gold and silver recovery in a refractory auriferous sulfurized mineral. The mineral was characterized using X-ray diffraction (XRD), atomic absorption spectrophotometry (AA) and fire test. The oxidizing agents used were: nitric acid, hydrogen peroxide and ozone; in all cases, cyanidation was used as a method to evaluate the oxidation efficiency and the release of gold. The oxidizing agent that generated the best Au and Ag recoveries in solution was HNO3, obtaining 80.4% Au and 29.5% Ag when working with particle size (d80) of 92 μm, solution 3 N and 2 hours of oxidation. A plant for the daily processing of 1 000 kg / day of ore equivalent to 30 000 kg / month was designed, obtaining 1.53 kg / month and 0.99 kg / month of Au and Ag respectively. When carrying out the economic pre-feasibility analysis, it was obtained that the project is viable for a life of 10 years; with a NPV of $ 624 362.50; TIR of 64.9%, investment recovery time of 1.8 years and cost-benefit ratio (B / C) of 2.01.