Treatment for gold ores with high content of carbonaceous matter

Abstract

Gold ores associated with carbonaceous matter present several difficulties in their extraction due to the ability of this matter to adsorb the aurocyanide complex from gold pregnant solutions, resulting in low extractions by direct cyanidation. This phenomenon is known as preg-robbing. In the present work, a process to effectively recover Au from a highly carbonaceous ore from Colombia is proposed, combining froth flotation using the organic polymer maltodextrin as a depressant of the carbonaceous matter and a pretreatment with a cationic surfactant (benzalkonium chloride) prior cyanidation in conjunction with activated carbon (CIL). The preg-robbing % (PR%) was reduced from the initial 39.5 % to 3.96 % in the flotation concentrates and a maximum of 87.26 % extraction of Au was achieved during cyanidation.