Quantitative analysis of gold in low-grade tailings from different matrices, coupled with a study into the associated uncertainties
| dc.contributor.author | Mashale, Kedibone Nicholine | |
| dc.contributor.co-supervisor | Tshilongo, James | |
| dc.contributor.supervisor | Chimuka, Luke | |
| dc.date.accessioned | 2024-10-21T13:05:46Z | |
| dc.date.available | 2024-10-21T13:05:46Z | |
| dc.date.issued | 2023 | |
| dc.description | A thesis submitted to the Faculty of Science, University of the Witwatersrand, in fulfillment of the requirements for the degree of Doctor of Philosophy, Johannesburg 2023 | |
| dc.description.abstract | Gold is one of the precious group elements that is used for various purposes, such as jewellery, auto catalysts and as a form of investment. Various countries have gold reserves, with South Africa being the leading gold producer between 1980 and 2007. However, as of 2022, it is ranked as the eighth largest producer of gold, contributing 3% to the global contribution. The majority of gold is mainly mined from the Witwatersrand Basin in Johannesburg. It is well known that mining has been ongoing for decades, which means that a significant amount of land has been mined across the country. During gold mining, a large proportion of the ore material from which the gold is extracted is waste, together with the chemicals that were used, and this waste is termed mine tailings. This implies that based on the years that gold mining has occurred for and the depth of mining, a significant amount of the tailings have been deposited into free land around the mines, some of which are close to communities. The tailings consist of traces of gold that were left due to inefficient extraction processes and other components, such as base metals. The disadvantage of this is that due to the other chemical composition of these tailings, they have the potential to be dangerous to the environment. Some tailings contain minerals such as jarosite (KFe2(SO4)2(OH)6) that cause acid mine drainage, while heavy metals such as lead, mercury, arsenic and chromium can leach into surface and ground waters, causing pollution. Furthermore, they pose a danger if the dams that they are stored in collapse, which was recently witnessed in South Africa. Because of these factors, there have been various advances made towards the beneficiation of tailings, such as utilizing them to make glass or bricks for construction. A major advancement was the reprocessing of these mine tailings to recover or extract the remaining gold, which benefits both the environment and the mining houses. Therefore, in a move to support this initiative, scientists have taken to the laboratory to develop new or optimize existing methods for the extraction and quantification of gold, which is expected to be of a low grade over time. Various methods can be used for the quantification of gold, including the conventional fire assay, wet and dry chlorination and acid digestion. Most of these are suitable for medium- to high-grade gold ores but are known to experience challenges in regard to low-grade ores. The aim of this research was therefore to find the optimum method for the quantification of gold from mine tailings emanating from the Ventersdorp Contact Reef (VCR) and Barberton Greenstone Belt (GBS). Subsequent to chemical analysis, the samples were characterized for mineralogy using X-ray diffraction (XRD) and Brunauer‒Emmett‒Teller (BET) surface area | |
| dc.description.sponsorship | NRF | |
| dc.description.sponsorship | Mintek | |
| dc.description.submitter | MM2024 | |
| dc.faculty | Faculty of Science | |
| dc.identifier | https://orcid.org/ 0000-0003-2502-5688 | |
| dc.identifier.citation | Mashale, Kedibone Nicholine. (2023). Quantitative analysis of gold in low-grade tailings from different matrices, coupled with a study into the associated uncertainties [PhD thesis, University of the Witwatersrand, Johannesburg]. WireDSpace. https://hdl.handle.net/10539/41790 | |
| dc.identifier.uri | https://hdl.handle.net/10539/41790 | |
| dc.language.iso | en | |
| dc.publisher | University of the Witwatersrand, Johannesburg | |
| dc.rights | © 2023 University of the Witwatersrand, Johannesburg. All rights reserved. The copyright in this work vests in the University of the Witwatersrand, Johannesburg. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of University of the Witwatersrand, Johannesburg. | |
| dc.rights.holder | University of the Witwatersrand, Johannesburg | |
| dc.school | School of Chemistry | |
| dc.subject | Mine trailing | |
| dc.subject | Fire essay | |
| dc.subject | Gold | |
| dc.subject | Acid digestion | |
| dc.subject | Chlorination | |
| dc.subject | UCTD | |
| dc.subject.other | SDG-12: Responsible consumption and production | |
| dc.title | Quantitative analysis of gold in low-grade tailings from different matrices, coupled with a study into the associated uncertainties | |
| dc.type | Thesis |