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Developing a methodology for reducing diamond breakage within processing plant
Diamond breakage has been a problem experienced by diamond operations. Material breakage characterisation methods has been used to determine the hardness or resistance to breakage of diamond host rock, ceramic diamond simulants and simulants embedded in the concrete blocks. This establishes a relati...
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| Format: | Thesis |
| Language: | English |
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Department of Chemical Engineering
2021
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| _version_ | 1867613235102875648 |
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| access_status_str | Open Access |
| author | Chele, Motsi John |
| author2 | Mainza, Aubrey |
| author_browse | Chele, Motsi John Mainza, Aubrey |
| author_facet | Mainza, Aubrey Chele, Motsi John |
| author_sort | Chele, Motsi John |
| collection | Thesis |
| description | Diamond breakage has been a problem experienced by diamond operations. Material breakage characterisation methods has been used to determine the hardness or resistance to breakage of diamond host rock, ceramic diamond simulants and simulants embedded in the concrete blocks. This establishes a relationship between specific input energy and degree of breakage that can be used for size reduction to minimise diamond breakage. Ceramic diamond simulants have been used in the process to identify areas that are more prevalent to diamond breakage. It was found that sections of high impact such as the cone crushers and drop height in the surge bins had the highest risk of diamond breakage. Kimberlite ore and ceramic diamond simulants were subjected to compressive breakage in drop weight test. The progeny particle size distribution and degree of breakage were compared. Standard breakage characterisation models were fitted to the breakage data of tested material and relative hardness parameters determined to establish the energy threshold. The breakage tests results showed that the ceramic diamond simulants were very hard while the kimberlite ore and concrete blocks were medium to soft. The material hardness parameters were determined from fitting the breakage data to the standard impact breakage characterisation models (t10-Ecs breakage model and Size dependent breakage model). Concrete blocks and Kimberlite ore showed less resistance to compressive breakage as demonstrated by higher A values compared to the ceramic diamond simulants. Applying material hardness categories presented by Napier-Munn et al (1999), Kimberlite ore was soft, concrete blocks ranged medium to soft and ceramic diamond simulants very hard. The remedial measures implemented in the process were to rubber line the concentrate bins in the recovery to minimise the impact forces, as well the surge bins in the process plant were controlled in such a way that reduces the drop height. Finally, the cone crushers and pan feeders operating philosophy has been improved to start at high speed to achieve choke feed conditions faster and to promote interparticle crushing. The close side settings were also optimized to reduce liner to liner interaction rather enhance particle-to-particle interaction. Through the optimised process, it had been observed that the diamond breakage had dropped below 5% level of the total stones recovered at +5cts. The methodology developed proved to be working after being tested in the chosen flowsheet. |
| format | Thesis |
| id | oai:open.uct.ac.za:11427/33681 |
| institution | University of Cape Town (South Africa) |
| language | eng |
| last_indexed | 2026-06-10T12:32:54.720Z |
| license_str | Not specified — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UCTD — University of Cape Town Open Access Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | Department of Chemical Engineering |
| publisherStr | Department of Chemical Engineering |
| record_format | dspace |
| source_str | UCTD — University of Cape Town Open Access Repository |
| spelling | oai:open.uct.ac.za:11427/33681 Developing a methodology for reducing diamond breakage within processing plant Chele, Motsi John Mainza, Aubrey Evertsson, Carl M Bremner, Sherry Chemical Engineering Diamond breakage has been a problem experienced by diamond operations. Material breakage characterisation methods has been used to determine the hardness or resistance to breakage of diamond host rock, ceramic diamond simulants and simulants embedded in the concrete blocks. This establishes a relationship between specific input energy and degree of breakage that can be used for size reduction to minimise diamond breakage. Ceramic diamond simulants have been used in the process to identify areas that are more prevalent to diamond breakage. It was found that sections of high impact such as the cone crushers and drop height in the surge bins had the highest risk of diamond breakage. Kimberlite ore and ceramic diamond simulants were subjected to compressive breakage in drop weight test. The progeny particle size distribution and degree of breakage were compared. Standard breakage characterisation models were fitted to the breakage data of tested material and relative hardness parameters determined to establish the energy threshold. The breakage tests results showed that the ceramic diamond simulants were very hard while the kimberlite ore and concrete blocks were medium to soft. The material hardness parameters were determined from fitting the breakage data to the standard impact breakage characterisation models (t10-Ecs breakage model and Size dependent breakage model). Concrete blocks and Kimberlite ore showed less resistance to compressive breakage as demonstrated by higher A values compared to the ceramic diamond simulants. Applying material hardness categories presented by Napier-Munn et al (1999), Kimberlite ore was soft, concrete blocks ranged medium to soft and ceramic diamond simulants very hard. The remedial measures implemented in the process were to rubber line the concentrate bins in the recovery to minimise the impact forces, as well the surge bins in the process plant were controlled in such a way that reduces the drop height. Finally, the cone crushers and pan feeders operating philosophy has been improved to start at high speed to achieve choke feed conditions faster and to promote interparticle crushing. The close side settings were also optimized to reduce liner to liner interaction rather enhance particle-to-particle interaction. Through the optimised process, it had been observed that the diamond breakage had dropped below 5% level of the total stones recovered at +5cts. The methodology developed proved to be working after being tested in the chosen flowsheet. 2021-08-03T09:57:32Z 2021-08-03T09:57:32Z 2021 2021-08-02T11:56:33Z Master Thesis Masters MSc http://hdl.handle.net/11427/33681 eng application/pdf Department of Chemical Engineering Faculty of Engineering and the Built Environment |
| spellingShingle | Chemical Engineering Chele, Motsi John Developing a methodology for reducing diamond breakage within processing plant |
| thesis_degree_str | Master's |
| title | Developing a methodology for reducing diamond breakage within processing plant |
| title_full | Developing a methodology for reducing diamond breakage within processing plant |
| title_fullStr | Developing a methodology for reducing diamond breakage within processing plant |
| title_full_unstemmed | Developing a methodology for reducing diamond breakage within processing plant |
| title_short | Developing a methodology for reducing diamond breakage within processing plant |
| title_sort | developing a methodology for reducing diamond breakage within processing plant |
| topic | Chemical Engineering |
| url | http://hdl.handle.net/11427/33681 |
| work_keys_str_mv | AT chelemotsijohn developingamethodologyforreducingdiamondbreakagewithinprocessingplant |