A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining
| dc.contributor.author | Manzila, Archippe Ngwey | |
| dc.contributor.author | Moyo, Thandazile | |
| dc.contributor.author | Petersen, Jochen | |
| dc.date.accessioned | 2023-09-18T10:58:38Z | |
| dc.date.available | 2023-09-18T10:58:38Z | |
| dc.date.issued | 2022-10-14 | |
| dc.date.updated | 2022-10-26T11:08:03Z | |
| dc.description.abstract | Mercury amalgamation is the method of choice to recover gold in artisanal and small-scale gold mining (ASGM). However, despite the low cost and simplicity of this method, the use of mercury presents serious health and environmental risks, as well as low efficiency in gold extraction. This study investigates the application of cyanide and thiosulphate leaching as alternatives to mercury amalgamation. This investigation was undertaken by conducting leach experiments using cyanide at 1 g/L, 3 g/L, and 5 g/L, and ammonium thiosulphate at 0.1 M and 0.5 M, on three ore samples originating from an artisanal mining area in Zimbabwe. The operating conditions (T = 26 °C, solids loading: 30%, particle size: −300 + 150 µm) were selected to mimic as closely as possible the conditions of artisanal mining processes. It was found that cyanide leaching was the better performing technology compared to thiosulphate leaching, as it achieved gold extractions of 71.6%, 69.7%, and 67.8% for the three ore samples (Sample 1, Sample 2, and Sample 3, respectively), whereas thiosulphate leaching achieved gold extractions of 54.1%, 35.6%, and 38.0% for the three ores, respectively. Both methods outperformed mercury amalgamation, which typically achieves gold recoveries of 30%–50%. Studying the minerology of the ores, using XRF, XRD, QEMSCAN, SEM-EDS, and a diagnostic leach, revealed the presence of sulphide minerals hosting refractory gold which contributed to the low gold extractions observed. Besides achieving higher gold extraction, cyanide leaching proved to be a system that is easier to control compared to thiosulphate leaching, making it much more attractive to artisanal miners. | |
| dc.identifier | doi: 10.3390/min12101291 | |
| dc.identifier.apacitation | Manzila, A. N., Moyo, T., & Petersen, J. (2022). A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining. <i>Minerals</i>, 12(10), 1291. http://hdl.handle.net/11427/38728 | en_ZA |
| dc.identifier.chicagocitation | Manzila, Archippe Ngwey, Thandazile Moyo, and Jochen Petersen "A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining." <i>Minerals</i> 12, 10. (2022): 1291. http://hdl.handle.net/11427/38728 | en_ZA |
| dc.identifier.citation | Manzila, A.N., Moyo, T. & Petersen, J. 2022. A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining. <i>Minerals.</i> 12(10):1291. http://hdl.handle.net/11427/38728 | en_ZA |
| dc.identifier.ris | TY - Journal Article AU - Manzila, Archippe Ngwey AU - Moyo, Thandazile AU - Petersen, Jochen AB - Mercury amalgamation is the method of choice to recover gold in artisanal and small-scale gold mining (ASGM). However, despite the low cost and simplicity of this method, the use of mercury presents serious health and environmental risks, as well as low efficiency in gold extraction. This study investigates the application of cyanide and thiosulphate leaching as alternatives to mercury amalgamation. This investigation was undertaken by conducting leach experiments using cyanide at 1 g/L, 3 g/L, and 5 g/L, and ammonium thiosulphate at 0.1 M and 0.5 M, on three ore samples originating from an artisanal mining area in Zimbabwe. The operating conditions (T = 26 °C, solids loading: 30%, particle size: −300 + 150 µm) were selected to mimic as closely as possible the conditions of artisanal mining processes. It was found that cyanide leaching was the better performing technology compared to thiosulphate leaching, as it achieved gold extractions of 71.6%, 69.7%, and 67.8% for the three ore samples (Sample 1, Sample 2, and Sample 3, respectively), whereas thiosulphate leaching achieved gold extractions of 54.1%, 35.6%, and 38.0% for the three ores, respectively. Both methods outperformed mercury amalgamation, which typically achieves gold recoveries of 30%–50%. Studying the minerology of the ores, using XRF, XRD, QEMSCAN, SEM-EDS, and a diagnostic leach, revealed the presence of sulphide minerals hosting refractory gold which contributed to the low gold extractions observed. Besides achieving higher gold extraction, cyanide leaching proved to be a system that is easier to control compared to thiosulphate leaching, making it much more attractive to artisanal miners. DA - 2022-10-14 DB - OpenUCT DP - University of Cape Town IS - 10 LK - https://open.uct.ac.za PY - 2022 T1 - A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining TI - A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining UR - http://hdl.handle.net/11427/38728 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/38728 | |
| dc.identifier.vancouvercitation | Manzila AN, Moyo T, Petersen J. A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining. Minerals. 2022;12(10):1291. http://hdl.handle.net/11427/38728. | en_ZA |
| dc.publisher | Multidisciplinary Digital Publishing Institute | |
| dc.publisher.department | Chemical Engineering | |
| dc.publisher.faculty | Faculty of Engineering and the Built Environment | |
| dc.rights.uri | http://creativecommons.org/licenses/by/4.0/ | |
| dc.source | Minerals | |
| dc.source.journalissue | 10 | |
| dc.source.journalvolume | 12 | |
| dc.source.pagination | 1291 | |
| dc.source.uri | https://www.mdpi.com/journal/minerals | |
| dc.title | A Study on the Applicability of Agitated Cyanide Leaching and Thiosulphate Leaching for Gold Extraction in Artisanal and Small-Scale Gold Mining | |
| dc.type | Journal Article |