Documents disponibles écrits par cet auteur

Ball motion, axial segregation and power consumption in a full scale two chamber cement mill / Paul W. Cleary in Minerals engineering, Vol. 22 N° 9/10 (Août/Septembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 809–820 Titre : Ball motion, axial segregation and power consumption in a full scale two chamber cement mill Type de document : texte imprimé Auteurs : Paul W. Cleary, Auteur Année de publication : 2009 Article en page(s) : pp. 809–820 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : DEM  Mill  Cement  Grinding  Particle  flow Résumé : Grinding of clinker for cement production is often performed in a two chamber ball mill. In the first shorter chamber, raw feed is ground using media consisting of large balls. The ground product of the first chamber exits through a discharge grate and enters the second longer chamber. Here smaller balls are used to grind the product material even finer. In this paper we analyse the charge motion, short term ball segregation processes and energy utilisation in a 4 m diameter cement ball mill using DEM. The power draw predicted is consistent with the rated power of the mill. The energy dissipation in the mill is dominated by shear interaction. The gentle liner profiles ensure that few balls move on cataracting trajectories. The distribution of energy utilisation between the different size media fractions is explored as are differences in the collisional environment between the two mill chambers. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900051X [article] Ball motion, axial segregation and power consumption in a full scale two chamber cement mill [texte imprimé] / Paul W. Cleary, Auteur . - 2009 . - pp. 809–820. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 9/10 (Août/Septembre 2009) . - pp. 809–820 Mots-clés : DEM  Mill  Cement  Grinding  Particle  flow Résumé : Grinding of clinker for cement production is often performed in a two chamber ball mill. In the first shorter chamber, raw feed is ground using media consisting of large balls. The ground product of the first chamber exits through a discharge grate and enters the second longer chamber. Here smaller balls are used to grind the product material even finer. In this paper we analyse the charge motion, short term ball segregation processes and energy utilisation in a 4 m diameter cement ball mill using DEM. The power draw predicted is consistent with the rated power of the mill. The energy dissipation in the mill is dominated by shear interaction. The gentle liner profiles ensure that few balls move on cataracting trajectories. The distribution of energy utilisation between the different size media fractions is explored as are differences in the collisional environment between the two mill chambers. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S089268750900051X

Separation performance of double deck banana screens / Paul W. Cleary in Minerals engineering, Vol. 22 N° 14 (Novembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 14 (Novembre 2009) . - pp. 1218–1229 Titre : Separation performance of double deck banana screens : Part 1: Flow and separation for different accelerations Type de document : texte imprimé Auteurs : Paul W. Cleary, Auteur ; Matthew D. Sinnott, Auteur ; Rob D. Morrison, Auteur Année de publication : 2009 Article en page(s) : pp. 1218–1229 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Screening  Separation  Discrete  element  method  DEM  Banana  screen Résumé : Banana screens are often used for high capacity separation of iron ore, coal and aggregates into different size fractions. They consist of one or more curved decks that are fitted with screen panels with arrays of square or rectangular holes. The screen structure is vibrated at high frequency to generate peak accelerations of around 4–6g which separates particles flowing over each screen according to their size. Screens are often used to close comminution circuits and return specific size fractions of rock to different destinations such as pebble mills, crushers and back into the mills. All multi-deck screens are difficult to sample for intermediate products which makes measurement and optimization very difficult. Banana screens are even more difficult because the screen cut size varies with the varying slope of the decks. In this paper, the discrete element method (DEM) is used to simulate a full industrial scale double deck banana screen for a range of accelerations. The nature of the particle flow through this complex machine is explored for a range of peak accelerations. Critical aspects of the flow are linked to the separation performance. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001551 [article] Separation performance of double deck banana screens : Part 1: Flow and separation for different accelerations [texte imprimé] / Paul W. Cleary, Auteur ; Matthew D. Sinnott, Auteur ; Rob D. Morrison, Auteur . - 2009 . - pp. 1218–1229. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 14 (Novembre 2009) . - pp. 1218–1229 Mots-clés : Screening  Separation  Discrete  element  method  DEM  Banana  screen Résumé : Banana screens are often used for high capacity separation of iron ore, coal and aggregates into different size fractions. They consist of one or more curved decks that are fitted with screen panels with arrays of square or rectangular holes. The screen structure is vibrated at high frequency to generate peak accelerations of around 4–6g which separates particles flowing over each screen according to their size. Screens are often used to close comminution circuits and return specific size fractions of rock to different destinations such as pebble mills, crushers and back into the mills. All multi-deck screens are difficult to sample for intermediate products which makes measurement and optimization very difficult. Banana screens are even more difficult because the screen cut size varies with the varying slope of the decks. In this paper, the discrete element method (DEM) is used to simulate a full industrial scale double deck banana screen for a range of accelerations. The nature of the particle flow through this complex machine is explored for a range of peak accelerations. Critical aspects of the flow are linked to the separation performance. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001551

Separation performance of double deck banana screens / Paul W. Cleary in Minerals engineering, Vol. 22 N° 14 (Novembre 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 14 (Novembre 2009) . - pp. 1230–1244 Titre : Separation performance of double deck banana screens Titre original : Part 2: Quantitative predictions Type de document : texte imprimé Auteurs : Paul W. Cleary, Auteur ; Matthew D. Sinnott, Auteur ; Rob D. Morrison, Auteur Année de publication : 2009 Article en page(s) : pp. 1230–1244 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Screening  Separation  Discrete  element  method  DEM  Banana  screen Résumé : Banana screens are often used for high capacity separation of iron ore, coal and aggregates into different size fractions. They consist of one or more curved decks that are fitted with screen panels with arrays of square or rectangular holes. The screen structure is vibrated while a dense stream of particles flows over it and is separated according to size. The material discharging from the top of the deck is the oversize and may become a coarse product or be crushed and recycled to the screen feed. The material falling through the deck can be further separated by additional decks below. Each lower deck returns a product stream and the material passing out through the bottom deck is the undersize. In this paper, Discrete Element Method (DEM) is used to explore the separation performance of a full industrial scale double deck banana screen for a peak acceleration of 5g. The separation efficiency of each deck is analysed and the individual contributions of each screen panel are assessed using outputs from the model. Residence time distributions for particles on each deck provide insight into both the transport characteristics along the deck and the separation performance through each deck. The top and bottom decks have very different flow behaviour with very different bed structure and motion. The stresses applied by the flowing particles to the screen cloths and the impact and abrasive wear on the screen surfaces are evaluated. Finally, the energy absorbed by particles provides insight into the extent of particle degradation produced by transiting the screen. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001563 [article] Separation performance of double deck banana screens = Part 2: Quantitative predictions [texte imprimé] / Paul W. Cleary, Auteur ; Matthew D. Sinnott, Auteur ; Rob D. Morrison, Auteur . - 2009 . - pp. 1230–1244. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 14 (Novembre 2009) . - pp. 1230–1244 Mots-clés : Screening  Separation  Discrete  element  method  DEM  Banana  screen Résumé : Banana screens are often used for high capacity separation of iron ore, coal and aggregates into different size fractions. They consist of one or more curved decks that are fitted with screen panels with arrays of square or rectangular holes. The screen structure is vibrated while a dense stream of particles flows over it and is separated according to size. The material discharging from the top of the deck is the oversize and may become a coarse product or be crushed and recycled to the screen feed. The material falling through the deck can be further separated by additional decks below. Each lower deck returns a product stream and the material passing out through the bottom deck is the undersize. In this paper, Discrete Element Method (DEM) is used to explore the separation performance of a full industrial scale double deck banana screen for a peak acceleration of 5g. The separation efficiency of each deck is analysed and the individual contributions of each screen panel are assessed using outputs from the model. Residence time distributions for particles on each deck provide insight into both the transport characteristics along the deck and the separation performance through each deck. The top and bottom decks have very different flow behaviour with very different bed structure and motion. The stresses applied by the flowing particles to the screen cloths and the impact and abrasive wear on the screen surfaces are evaluated. Finally, the energy absorbed by particles provides insight into the extent of particle degradation produced by transiting the screen. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509001563

Using DEM to compare the energy efficiency of pilot scale ball and tower mills / Rob D. Morrison in Minerals engineering, Vol. 22 N° 7/8 (Juin/Juillet 2009) 

Public ISBD [article]  in Minerals engineering > Vol. 22 N° 7/8 (Juin/Juillet 2009) . - pp. 665–672 Titre : Using DEM to compare the energy efficiency of pilot scale ball and tower mills Type de document : texte imprimé Auteurs : Rob D. Morrison, Auteur ; Paul W. Cleary, Auteur ; Matthew D. Sinnott, Auteur Année de publication : 2009 Article en page(s) : pp. 665–672 Note générale : Génie Minier Langues : Anglais (eng) Mots-clés : Comminution  Grinding  and  fine  particle  processing Résumé : Tower mills are considered to be appreciably more energy efficient than ball mills. Why this should be so is a question which can be explored by using DEM to simulate one machine of each type with similar breakage capabilities. This paper reports on a comparison between a pilot scale tower mill and a small ball mill in terms of the power required to produce reasonably similar distributions of normal and tangential impacts. While the tower mill produces quite a narrow spectrum of normal energies, the ball mill produces a wide distribution. Hence, the ball mill can be expected to be much more “forgiving” of variable feed conditions but much less efficient in terms of utilization of the energy from media interactions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000302 [article] Using DEM to compare the energy efficiency of pilot scale ball and tower mills [texte imprimé] / Rob D. Morrison, Auteur ; Paul W. Cleary, Auteur ; Matthew D. Sinnott, Auteur . - 2009 . - pp. 665–672. Génie Minier Langues : Anglais (eng) in Minerals engineering > Vol. 22 N° 7/8 (Juin/Juillet 2009) . - pp. 665–672 Mots-clés : Comminution  Grinding  and  fine  particle  processing Résumé : Tower mills are considered to be appreciably more energy efficient than ball mills. Why this should be so is a question which can be explored by using DEM to simulate one machine of each type with similar breakage capabilities. This paper reports on a comparison between a pilot scale tower mill and a small ball mill in terms of the power required to produce reasonably similar distributions of normal and tangential impacts. While the tower mill produces quite a narrow spectrum of normal energies, the ball mill produces a wide distribution. Hence, the ball mill can be expected to be much more “forgiving” of variable feed conditions but much less efficient in terms of utilization of the energy from media interactions. DEWEY : 622 ISSN : 0892-6875 En ligne : http://www.sciencedirect.com/science/article/pii/S0892687509000302