Speciation and quantification of surface

An increasing number of low-grade gold ore deposits are characterized by the presence of gold as solid solution into the mineral matrix of sulphide minerals which is not directly amenable to gold cyanidation. In order to liberate this submicroscopic gold, the ore has to be oxidized before being subjected to gold cyanidation and extraction. This study investigates the impact of active carbonaceous compounds on gold recovery during autoclave pressure oxidation (AC POX). Using the time of flight secondary ion mass spectrometry (TOF-SIMS) technique, gold species were directly determined on individual carbonaceous particulates from AC POX stream samples. The findings revealed both metallic gold and Au(CN)2 compounds present in the carbonaceous matter from carbon-in-leach (CIL) tail samples. Quantification of these gold forms allowed for an estimation of the loss of gold through preg-robbing by carbonaceous material during the AC POX oxidation process. This research contributes to a better understanding of gold recovery challenges and proposes a new analytical approach to optimize the mining process during gold extraction.