Resumen

ZAMORA ECHENIQUE, Gerardo; HINOJOSA CARRASCO, Octavio  y  GOMEZ PORREZ, Karem Paola. Aluvial gold recovery, without the use of mercury. REV. MAMYM [online]. 2021, vol.6, n.1, pp.48-58. ISSN 2519-5352.

Abstract Currently, there are more than 10 to 15 million artisanal gold miners in more than 70 countries in the world. It is also estimated that about 30% of the world's gold production comes from artisanal mining. This activity has spread dangerously in many regions that do not adequately control their environmental laws and one of these regions is South America, specifically the Amazon, a region that involves 9 countries; and even territory equivalent to 7.8 million km2, in which about 33 million people live in more than 385 indigenous towns. This entire area is being affected by the legal and illegal exploitation of alluvial gold found in rivers, the negative environmental impact it generates is enormous. In this context, this research work proposes a technical alternative for the recovery of gold from alluvial sediments by applying centrifugal gravimetric concentration, thus avoiding the use of mercury. The characterization of the studied sample shows d80 = 3200 microns (3.2 mm) and d50 = 400 microns (0.4 mm); on the other hand, the gold content is 4.05 g / t, which is liberated and with the highest content in the particle size fractions below -48 + 200 Tyler mesh. According to the metallurgical balances it can be verified that the recovery of gold in the different stages of the process (pre concentration - concentration - amalgamation and / or fusion) is always above 90%. The efficiencies of the melting stage of the concentrates obtained are greater than 95%. From the point of view of the total recovery of Au, it has that, in the Knelson-Mesa-Amalgamation process, it is 73.08%; while, for the Knelson-Mesa-Fusion process, 76.67%; in addition, for the Knelson-Knelson-Amalgamation process, 64.65% and, finally, Knelson-Knelson-Fusion, 66.53% of total recovery. The conclusions of the work show that the alluvial gold sample responds favorably to the process of gravimetric concentration and centrifugation, and it is absolutely possible to totally or partially dispense with mercury in its treatment. By totally eliminating the use of mercury, it is possible to reach metallic gold by melting the concentrates obtained, even in better recovery conditions than amalgamation.

Palabras clave : Mercury-free Au concentration; Centrifugal Au concentration.