Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles
| dc.contributor.author | Tupikina, Olga V | |
| dc.contributor.author | Minnaar, Susanna H | |
| dc.contributor.author | Rautenbach, George F | |
| dc.contributor.author | Dew, David W | |
| dc.contributor.author | Harrison, Susan T L | |
| dc.date.accessioned | 2016-08-18T10:10:03Z | |
| dc.date.available | 2016-08-18T10:10:03Z | |
| dc.date.issued | 2012 | |
| dc.date.updated | 2016-08-18T10:07:44Z | |
| dc.description.abstract | Bioheap leaching of low grade copper sulphides has been applied successfully at the commercial scale for the extraction of copper from secondary sulphide minerals. It is important to optimise the inoculation of heaps in order to minimise the residence time required for the heap and to maximise extraction.Thermophilic bioleaching of the primary sulphide chalcopyrite poses an additional challenge of rising temperatures inside the heap demanding microbial succession. After heap start up, rising heap core temperatures make conditions less favourable for mesophilic microbial species, and the moderately thermophilic community succeeds them in the consortium. In turn, thermophilic microorganisms succeed the moderately thermophilic microbes as the higher temperatures are reached.A detailed understanding of the microbial colonisation of whole ore is necessary to optimise microbial succession during thermophilic bioleaching, as is that of microbial growth kinetics on whole ore. Most published research is focused on microbial growth rates of bioleaching organisms in liquid cultures; little work is reported on microbial colonisation of whole ore and subsequent microbial activity. To extend the information available on the microbial diversity and succession in a bioleaching habitat, a study of bioleaching microbes colonising the ore body is required.The aim of this work was to explore aspects of colonisation of low grade chalcopyrite ore at 23 °C, 50 °C and 65 °C by acidophilic micro-organisms. Laboratory column packed bed reactors were designed to simulate heap leach environments and to provide a systematic way of studying microbial dynamics on whole ore. The effect of inoculum size and inoculation strategies on microbial activity established and the subsequent leaching performance were investigated under conditions that support mesophilic, moderately thermophilic and thermophilic microorganisms. A relationship was shown between the inoculum size and the culture time required to achieve Eh values greater than 700 mV, especially at 23 °C and 65 °C. However, the culture time required to establish an active iron- (and sulphur-) oxidising culture was also influenced by ore type, irrigation rate and inoculum adaptation. The effect on effluent Eh, pH and dissolved iron levels is also discussed. | en_ZA |
| dc.identifier | http://dx.doi.org/10.1016/j.hydromet.2013.10.010 | |
| dc.identifier.apacitation | Tupikina, O. V., Minnaar, S. H., Rautenbach, G. F., Dew, D. W., & Harrison, S. T. L. (2012). Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles. <i>Hydrometallurgy</i>, http://hdl.handle.net/11427/21309 | en_ZA |
| dc.identifier.chicagocitation | Tupikina, Olga V, Susanna H Minnaar, George F Rautenbach, David W Dew, and Susan T L Harrison "Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles." <i>Hydrometallurgy</i> (2012) http://hdl.handle.net/11427/21309 | en_ZA |
| dc.identifier.citation | Tupikina, O. V., Minnaar, S. H., Rautenbach, G. F., Dew, D. W., & Harrison, S. T. (2014). Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles. Hydrometallurgy, 149, 244-251. | en_ZA |
| dc.identifier.issn | 0304-386X | en_ZA |
| dc.identifier.ris | TY - Journal Article AU - Tupikina, Olga V AU - Minnaar, Susanna H AU - Rautenbach, George F AU - Dew, David W AU - Harrison, Susan T L AB - Bioheap leaching of low grade copper sulphides has been applied successfully at the commercial scale for the extraction of copper from secondary sulphide minerals. It is important to optimise the inoculation of heaps in order to minimise the residence time required for the heap and to maximise extraction.Thermophilic bioleaching of the primary sulphide chalcopyrite poses an additional challenge of rising temperatures inside the heap demanding microbial succession. After heap start up, rising heap core temperatures make conditions less favourable for mesophilic microbial species, and the moderately thermophilic community succeeds them in the consortium. In turn, thermophilic microorganisms succeed the moderately thermophilic microbes as the higher temperatures are reached.A detailed understanding of the microbial colonisation of whole ore is necessary to optimise microbial succession during thermophilic bioleaching, as is that of microbial growth kinetics on whole ore. Most published research is focused on microbial growth rates of bioleaching organisms in liquid cultures; little work is reported on microbial colonisation of whole ore and subsequent microbial activity. To extend the information available on the microbial diversity and succession in a bioleaching habitat, a study of bioleaching microbes colonising the ore body is required.The aim of this work was to explore aspects of colonisation of low grade chalcopyrite ore at 23 °C, 50 °C and 65 °C by acidophilic micro-organisms. Laboratory column packed bed reactors were designed to simulate heap leach environments and to provide a systematic way of studying microbial dynamics on whole ore. The effect of inoculum size and inoculation strategies on microbial activity established and the subsequent leaching performance were investigated under conditions that support mesophilic, moderately thermophilic and thermophilic microorganisms. A relationship was shown between the inoculum size and the culture time required to achieve Eh values greater than 700 mV, especially at 23 °C and 65 °C. However, the culture time required to establish an active iron- (and sulphur-) oxidising culture was also influenced by ore type, irrigation rate and inoculum adaptation. The effect on effluent Eh, pH and dissolved iron levels is also discussed. DA - 2012 DB - OpenUCT DP - University of Cape Town J1 - Hydrometallurgy LK - https://open.uct.ac.za PB - University of Cape Town PY - 2012 SM - 0304-386X T1 - Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles TI - Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles UR - http://hdl.handle.net/11427/21309 ER - | en_ZA |
| dc.identifier.uri | http://hdl.handle.net/11427/21309 | |
| dc.identifier.uri | http://www.sciencedirect.com/science/article/pii/S0304386X13002107 | |
| dc.identifier.vancouvercitation | Tupikina OV, Minnaar SH, Rautenbach GF, Dew DW, Harrison STL. Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles. Hydrometallurgy. 2012; http://hdl.handle.net/11427/21309. | en_ZA |
| dc.language | eng | en_ZA |
| dc.publisher | Elsevier | en_ZA |
| dc.publisher.institution | University of Cape Town | |
| dc.source | Hydrometallurgy | en_ZA |
| dc.source.uri | http://www.sciencedirect.com/science/journal/0304386X | |
| dc.subject.other | Bioleaching | |
| dc.subject.other | Chalcopyrite | |
| dc.subject.other | Mesophilic | |
| dc.subject.other | Microbial colonisation | |
| dc.subject.other | Heap inoculation | |
| dc.title | Effect of inoculum size on the rates of whole ore colonisation of mesophilic, moderate thermophilic and thermophilic acidophiles | en_ZA |
| dc.type | Journal Article | en_ZA |
| uct.type.filetype | Text | |
| uct.type.filetype | Image | |
| uct.type.publication | Research | en_ZA |
| uct.type.resource | Article | en_ZA |