The fracture and autogenous comminution of quartzite

 

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dc.contributor.advisor Ball, Anthony en_ZA
dc.contributor.author Kanellopoulos, Achilles Constantine en_ZA
dc.date.accessioned 2016-03-21T19:01:59Z
dc.date.available 2016-03-21T19:01:59Z
dc.date.issued 1978 en_ZA
dc.identifier.citation Kanellopoulos, A. 1978. The fracture and autogenous comminution of quartzite. University of Cape Town. en_ZA
dc.identifier.uri http://hdl.handle.net/11427/18008
dc.description Bibliography: p.103-116. en_ZA
dc.description.abstract Comminution is the process which aims at increasing the surface area and the resultant liberation of a particular constituent from the mass of a solid. The autogenous mill uses tumbling to effect comminution, but instead of special milling bodies being added, pebbles of the material to be comminuted are used. The autogenous comminution process utilises less than 0,1 per cent of the energy input. The principal objective of the present work was to analyse autogenous milling behaviour in terms of the individual comminuting mechanisms and to establish the inter-relationships between the main process variables, namely rock petrography, size distribution of the feed, applied load, relative velocity and environment. In this manner the optimisation of the process and an improvement of its efficiency was sought. In addition the establishment of testing procedures to predict the autogenous milling behaviour of a given type of rock was aimed. In the present work the gold bearing Witwatersrand quartzite was used, although the findings are applicable to other types of rocks. Since fracture phenomena are involved in all comminuting mechanisms of impact-compression, chipping and abrasion, slow compression and Brazilian tests were performed. The grain size and the mineral composition of the rock has been found to have a large influence on the local stresses required for these processes. Indeed the results show that the fragility and therefore ease of comminution increases with increasing grain size of the quartzite. Brazilian tests on drill cores of varying diameters may allow the prediction of the critical size of rock of the mill feed which can survive in a mill of given characteristics. en_ZA
dc.language.iso eng en_ZA
dc.subject.other Materials Engineering en_ZA
dc.title The fracture and autogenous comminution of quartzite en_ZA
dc.type Doctoral Thesis
uct.type.publication Research en_ZA
uct.type.resource Thesis en_ZA
dc.publisher.institution University of Cape Town
dc.publisher.faculty Faculty of Engineering and the Built Environment
dc.publisher.department Centre for Materials Engineering en_ZA
dc.type.qualificationlevel Doctoral
dc.type.qualificationname PhD en_ZA
uct.type.filetype Text
uct.type.filetype Image
dc.identifier.apacitation Kanellopoulos, A. C. (1978). <i>The fracture and autogenous comminution of quartzite</i>. (Thesis). University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering. Retrieved from http://hdl.handle.net/11427/18008 en_ZA
dc.identifier.chicagocitation Kanellopoulos, Achilles Constantine. <i>"The fracture and autogenous comminution of quartzite."</i> Thesis., University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1978. http://hdl.handle.net/11427/18008 en_ZA
dc.identifier.vancouvercitation Kanellopoulos AC. The fracture and autogenous comminution of quartzite. [Thesis]. University of Cape Town ,Faculty of Engineering & the Built Environment ,Centre for Materials Engineering, 1978 [cited yyyy month dd]. Available from: http://hdl.handle.net/11427/18008 en_ZA
dc.identifier.ris TY - Thesis / Dissertation AU - Kanellopoulos, Achilles Constantine AB - Comminution is the process which aims at increasing the surface area and the resultant liberation of a particular constituent from the mass of a solid. The autogenous mill uses tumbling to effect comminution, but instead of special milling bodies being added, pebbles of the material to be comminuted are used. The autogenous comminution process utilises less than 0,1 per cent of the energy input. The principal objective of the present work was to analyse autogenous milling behaviour in terms of the individual comminuting mechanisms and to establish the inter-relationships between the main process variables, namely rock petrography, size distribution of the feed, applied load, relative velocity and environment. In this manner the optimisation of the process and an improvement of its efficiency was sought. In addition the establishment of testing procedures to predict the autogenous milling behaviour of a given type of rock was aimed. In the present work the gold bearing Witwatersrand quartzite was used, although the findings are applicable to other types of rocks. Since fracture phenomena are involved in all comminuting mechanisms of impact-compression, chipping and abrasion, slow compression and Brazilian tests were performed. The grain size and the mineral composition of the rock has been found to have a large influence on the local stresses required for these processes. Indeed the results show that the fragility and therefore ease of comminution increases with increasing grain size of the quartzite. Brazilian tests on drill cores of varying diameters may allow the prediction of the critical size of rock of the mill feed which can survive in a mill of given characteristics. DA - 1978 DB - OpenUCT DP - University of Cape Town LK - https://open.uct.ac.za PB - University of Cape Town PY - 1978 T1 - The fracture and autogenous comminution of quartzite TI - The fracture and autogenous comminution of quartzite UR - http://hdl.handle.net/11427/18008 ER - en_ZA


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