CHEMISTRY AS ENVIRONMENTAL ASSISTANCE OF ECOSYSTEMS AND POPULATIONS IN PERU

Abstract

Informal gold mining nationally and internationally has an important annual production that often exceeds formal production, the gold recovery technology used is the classic Mercury Amalgamation:

MAu + Hg → Au-Hg + M

Au – Hg → Au + Hg ↑

Given the MINAMATA Convention that specifies the dangers of Mercury for ecosystems and the health of populations, it is good to opt for technologies other than conventional Amalgamation - Cyanuration widely used in informal and formal mining to process your minerals and tailings. Elsner in 1846 correctly identified the chemical reaction that forms the basis of all cyanide leaching processes in gold: 4 Au + 8 NaCN + O2 + 2 H2O → 4 Na [Au (CN) 2] + 4 NaOH. In the context of clean technologies, it is necessary to resort to alternative metallurgical processes for gold recovery such as gravimetric concentration and leaching by agitation using Tiourea, Sandioss and Goldmax among other reagents. We show the reactions of the Gold recovery process by Tiourea:

2 (CS (NH2)2)2+ ↔ NH2 (NH) CSSC (NH) NH2 + 2 H+ + 2 e-

2 Au+ + NH2 (NH) CSSC (NH) NH2   + 2 H+ + e- ↔ 2 Au (CS (NH2)2)2+

2 Au (CS (NH2)2)2+    + e-    ↔ 2 Au0 + 2 (CS (NH2)2)2+

We show results of modeling and simulation of experimental data in obtaining Gold and Silver, considering the need to use processes that do not affect the environment and life, where to process minerals with high content of arsenic, antimony and copper that are cyanicides, as well as their subsequent remediation, they are uneconomic. Laboratory tests were performed to obtain working parameters in order to achieve optimal recovery percentages and moderate reagent consumption. The tests were performed by stirring using activated carbon, the results are shown in the graphs at the end of the work.