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Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching
Dissertation (MSc)--University of Pretoria, 2016.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2016
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| _version_ | 1867613709970440192 |
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| access_status_str | Open Access |
| author2 | Sandenbergh, R.F. |
| author_browse | Sandenbergh, R.F. |
| author_facet | Sandenbergh, R.F. |
| collection | Thesis |
| dc_rights_str_mv | © 2016 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MSc)--University of Pretoria, 2016. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/57485 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:40:28.124Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2016 |
| publishDateRange | 2016 |
| publishDateSort | 2016 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/57485 Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching Sandenbergh, R.F. u13376579@tuks.co.za Kandengwa, Michael UCTD Jarosite Biooxidation Cyanide Gold leaching Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Dissertation (MSc)--University of Pretoria, 2016. Biooxidation is an attractive process for unlocking of gold from refractory ores, but could be further improved by reducing the rather high cyanide consumption during the cyanidation of the biooxidation residues. The high cyanide demand is typically ascribed to the presence of metastable intermediate sulfur species formed during the oxidation of the sulfide, but it is also conceivable that jarosite formation during the acidic biooxidation process and subsequent leaching during the alkaline cyanidation could also account for significant cyanide consumption. The present work was done to establish if jarosite would readily form under typical biooxidation conditions and, if so, if it would then leach during cyanidation. Methods to stabilise or remove the jarosite were also investigated. To this end crystalline potassium jarosite was synthesized simulating conditions for the mesophile BIOX? process and its decomposition in alkaline media at pH 10.5 to 11 at 25?C investigated. It was found that it transformed into another amorphous iron compound as indicated by a change in colour from yellow to reddish, the presence of potassium and sulfate ions in solution, as well as the disappearance of the characteristic XRD pattern of jarosite. The jarosite also leached in aqueous alkaline cyanide as indicated by the presence of iron in solution, with increased leaching at higher cyanide concentrations. The jarosite could not be totally passified by aging, but removing it by leaching with an iron-complexing agent like oxalic acid was found to be possible. The consumption of cyanide by jarosite during gold leaching could thus be significant, but would obviously depend on how much jarosite is formed during the bioleaching process. Jarosite was observed to be present in the mesophile and thermophile BIOX? products from Fairview Mine with more jarosite present in the products of the thermophile process. The process jarosite was significantly more stable than that produced in the laboratory during alkaline cyanidation with 17 mass percent of the jarosite converted to ferric hydroxide for the process jarosite compared to complete conversion for the laboratory jarosite for a 24 hours leaching period. However, it still accounted for a significant amount of the cyanide consumed. tm2016 mi2025 Materials Science and Metallurgical Engineering MSc Unrestricted SDG-04: Quality education SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production SDG-08: Decent work and economic growth 2016-10-27T07:28:31Z 2016-10-27T07:28:31Z 2016-09-01 2016 Dissertation Kandengwa, M 2016, Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching, MSc Dissertation, University of Pretoria, Pretoria, viewed yymmdd <http://hdl.handle.net/2263/57485> S2016 http://hdl.handle.net/2263/57485 en © 2016 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | UCTD Jarosite Biooxidation Cyanide Gold leaching Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching |
| title | Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching |
| title_full | Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching |
| title_fullStr | Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching |
| title_full_unstemmed | Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching |
| title_short | Characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching |
| title_sort | characterization of jarosite formed during biooxidation of refractory gold ores and its effect on cyanide consumption during gold leaching |
| topic | UCTD Jarosite Biooxidation Cyanide Gold leaching Engineering, built environment and information technology theses SDG-04 SDG-04: Quality education Engineering, built environment and information technology theses SDG-09 SDG-09: Industry, innovation and infrastructure Engineering, built environment and information technology theses SDG-12 SDG-12: Responsible consumption and production Engineering, built environment and information technology theses SDG-08 SDG-08: Decent work and economic growth |
| url | http://hdl.handle.net/2263/57485 |