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Modelling comminution devices using DEM
Author(s) -
Cleary Paul
Publication year - 2001
Publication title -
international journal for numerical and analytical methods in geomechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.419
H-Index - 91
eISSN - 1096-9853
pISSN - 0363-9061
DOI - 10.1002/1096-9853(200101)25:1<83::aid-nag120>3.0.co;2-k
Subject(s) - comminution , discrete element method , breakage , mill , ball mill , mechanics , roller mill , rotational speed , particle size , torque , granular material , specific energy , materials science , energy consumption , range (aeronautics) , mechanical engineering , particle (ecology) , engineering , composite material , physics , metallurgy , geology , electrical engineering , oceanography , quantum mechanics , chemical engineering , thermodynamics
Particle size reduction, or milling, is an essential component of mineral processing and is important in other industry sectors. This needs to be done as efficiently as possible, maximizing mill throughput while minimizing operating costs. Such milling processes typically use only 1–5 per cent of the supplied energy for particle breakage, which leaves room for improvement. In discrete element modelling (DEM) of granular flows the trajectories, orientations and spins of all the particles and objects in the system are calculated and their interactions with other particles and with their environment are predicted. It is necessary to simulate particles of many different sizes and densities interacting with complex‐shaped objects moving in different ways. Particle flows in three types of mills; a 5 m ball mill, a 10 mm SAG mill and a 15 cm diameter centrifugal mill are predicted. Charge behaviour, torque and power draw are analysed for a range of rotation rates from 50 to 130 per cent of the critical speed for the ball mill. Sensitivity of the results to material properties and size distribution are examined. Radial size segregation is shown to occur and increases strongly with mill speed. Charge motion and power consumption for the SAG mill are predicted. Compari son of simulated flow patterns for the centrifugal mill with high‐speed experimental photographs reveals close agreement. The limitations and restrictions of this type of DEM model are discussed in detail. Copyright © 2001 John Wiley & Sons, Ltd.