Recovery of mercury of amalgams in digging gold - retorta RHYP

Abstract

Among the heavy metal ions, the mercury cations are especially prominent because they are not biodegradable and because of their capacity to accumulate in organisms along the food chain, magnifying themselves. Once absorbed the mercury ions cause, among others, neurological damage, cerebral palsy, tremors, muscle fibrillation, pulmonary irritation, renal impairment, etc. and even death. Small-scale, homemade gold extraction is usually carried out in diggings from metal mercury in the form of amalgams. This technique is one of the major sources of mercury pollution in the environment and, therefore, it is always necessary to use instruments that minimize its effects. This was the stimulus for the development of the Retorta RHYP that was developed in the Laboratory of Chemistry, the Institute of Geosciences of the University of São Paulo, presented in this paper. In addition to being extremely low cost, easy to assemble, it recovers mercury from amalgam of gold to values close to 100%. It is a retort that still has the advantage of being easy to carry and that does not require refrigeration. Despite little dissemination, The Retorta RHYP has been used in many countries in Africa, The Philippines and also in some South American countries, requiring further dissemination through work such as this one being presented.