Documents disponibles écrits par cet auteur

Bonded-particle modelling of microwave-induced damage in ore particles / A.Y. Ali in Minerals engineering, Vol. 23 N° 10 (Septembre 2010) 

Public ISBD [article]  in Minerals engineering > Vol. 23 N° 10 (Septembre 2010) . - pp. 780–790 Titre : Bonded-particle modelling of microwave-induced damage in ore particles Type de document : texte imprimé Auteurs : A.Y. Ali, Auteur ; S. M. Bradshaw, Auteur Année de publication : 2011 Article en page(s) : pp. 780–790 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Discrete  element  modelling  Liberation Résumé : Microwave heating of mineral ores offers a mechanism to induce fractures around grain boundaries due to the different rates of microwave power dissipation and the differences in thermal expansion coefficient among various minerals in the ore particles. As a consequence, this has the potential to reduce the energy required in subsequent grinding and to enhance liberation of valuable minerals. In this paper, numerical simulation using a bonded-particle model was undertaken to provide a better understanding of the mechanism of microwave-induced micro-fracture and to predict the effect of microwave power delivery and ore texture on microwave treatment of ores. Computational simulations of microwave heating and thermal damage have been carried out on two-phase conceptual ores. It was shown that the extent of damage and the crack pattern in an ore sample for the same microwave energy input depend strongly on the applied power density and the microwave absorbent phase grain size. It is possible both to reduce the energy input and to localize the microwave-induced damage around the grain boundaries by operating at high power density. It was also shown that high power pulsed equipment would be more efficient than continuous wave equipment for treating fine-grained ores. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001524 [article] Bonded-particle modelling of microwave-induced damage in ore particles [texte imprimé] / A.Y. Ali, Auteur ; S. M. Bradshaw, Auteur . - 2011 . - pp. 780–790. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 23 N° 10 (Septembre 2010) . - pp. 780–790 Mots-clés : Discrete  element  modelling  Liberation Résumé : Microwave heating of mineral ores offers a mechanism to induce fractures around grain boundaries due to the different rates of microwave power dissipation and the differences in thermal expansion coefficient among various minerals in the ore particles. As a consequence, this has the potential to reduce the energy required in subsequent grinding and to enhance liberation of valuable minerals. In this paper, numerical simulation using a bonded-particle model was undertaken to provide a better understanding of the mechanism of microwave-induced micro-fracture and to predict the effect of microwave power delivery and ore texture on microwave treatment of ores. Computational simulations of microwave heating and thermal damage have been carried out on two-phase conceptual ores. It was shown that the extent of damage and the crack pattern in an ore sample for the same microwave energy input depend strongly on the applied power density and the microwave absorbent phase grain size. It is possible both to reduce the energy input and to localize the microwave-induced damage around the grain boundaries by operating at high power density. It was also shown that high power pulsed equipment would be more efficient than continuous wave equipment for treating fine-grained ores. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687510001524

Computational fluid dynamic modelling of an electric furnace used in the smelting of PGM containing concentrates / J. J. Bezuidenhout in Minerals engineering, Vol. 22 N° 11 (Octobre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 995–1006 Titre : Computational fluid dynamic modelling of an electric furnace used in the smelting of PGM containing concentrates Type de document : texte imprimé Auteurs : J. J. Bezuidenhout, Auteur ; J.J. Eksteen, Auteur ; S. M. Bradshaw, Auteur Année de publication : 2009 Article en page(s) : pp. 995–1006 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Computational  fluid  dynamics  Modelling  Electric  refining  Pyrometallurgy Résumé : A complete three-dimensional computational fluid dynamic model has been developed to investigate the internal dynamics of a circular, three-phase electrical furnace as used for the smelting of Platinum Group Metal (PGM) concentrates. The model included multi-phase interactions between multiple fluid layers and CO-gas bubble release from the immersed electrode surface while three-phase AC electrical current was simulated at the electrodes. The model further accounts for the heat associated with the melting of concentrate which was thermodynamically calculated and incorporated by assuming zones of varying smelting intensity within the concentrate layer. The relationship between electrode immersion depths, at 15%, 35% and 55% in the slag, and the current distribution and slag electrical resistivity has been quantified while the temperature and velocity fields were obtained for 35% electrode immersion model, a typical operation case. The slag was identified as being at a fairly uniform temperature due to the mixing induced by natural buoyancy and the CO-bubble-momentum with the highest flow noted between and directly around the electrodes. The matte showed a stratified temperature distribution with little flow activity. The model results were found to correlate well with previously published studies and actual operating parameters. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000740 [article] Computational fluid dynamic modelling of an electric furnace used in the smelting of PGM containing concentrates [texte imprimé] / J. J. Bezuidenhout, Auteur ; J.J. Eksteen, Auteur ; S. M. Bradshaw, Auteur . - 2009 . - pp. 995–1006. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 11 (Octobre 2009) . - pp. 995–1006 Mots-clés : Computational  fluid  dynamics  Modelling  Electric  refining  Pyrometallurgy Résumé : A complete three-dimensional computational fluid dynamic model has been developed to investigate the internal dynamics of a circular, three-phase electrical furnace as used for the smelting of Platinum Group Metal (PGM) concentrates. The model included multi-phase interactions between multiple fluid layers and CO-gas bubble release from the immersed electrode surface while three-phase AC electrical current was simulated at the electrodes. The model further accounts for the heat associated with the melting of concentrate which was thermodynamically calculated and incorporated by assuming zones of varying smelting intensity within the concentrate layer. The relationship between electrode immersion depths, at 15%, 35% and 55% in the slag, and the current distribution and slag electrical resistivity has been quantified while the temperature and velocity fields were obtained for 35% electrode immersion model, a typical operation case. The slag was identified as being at a fairly uniform temperature due to the mixing induced by natural buoyancy and the CO-bubble-momentum with the highest flow noted between and directly around the electrodes. The matte showed a stratified temperature distribution with little flow activity. The model results were found to correlate well with previously published studies and actual operating parameters. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000740