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.

Mineralogical characteristics of sulfuric acid formation during bacterial oxidation of flotation concentrate

“…In present time the world's reserves of deposits with high initial content and easily recoverable ores are practically depleted and at the same time the share of gold is increasing in primaryh rudah, related to the category of persistent gold-bearing mineral raw materials. These minerals consist ofIt mainly from pyrite, arsenopyrite, chalcopyrite, hydroarsenatebut iron, oxidebut manganese and othersh [1][2].…”

“…The direct mechanism requires close physical contact between the bacteria and the mineral surface to ensure that the bacteria attach to the mineral, while the indirect mechanism involves the action of bacterial-generated iron sulfate (III). Iron ions are mainly found in the composition of ore minerals-pyrite (FeS2) and arsenopyrite (FeAsS), also as part of the fayalita (Fe 2 [SiCl 4 ]) [1,4].…”