A detailed breakage model implemented in commercial DEM platforms

Often in several particulate systems that are object of simulation using the Discrete Element Method (DEM) breakage of particles can occur. The extent of this breakage can be significant, such as in crushers and mills, which are meant to do exactly that; or not so significant, such as when particles are subjected to operations such as transportation, handling, mixing, compaction and separation, where breakage is not desired. In all these cases, however, conducting DEM simulations without accounting for breakage can lead to biased results, and sometimes even useless ones.

The description of breakage in DEM is still limited and very computationally demanding. Several approaches have been proposed to mimic particle breakage. Yet, these methods disregard important material properties and their validity over the range of conditions encountered in practice is still scarcely reported. A breakage model developed by the author and co-workers has been implemented in the two leading simulation platforms, that is, Rocky DEM and EDEM, being named “Tavares Breakage Model” and “Breakage Model based on Tavares (UFRJ)”, respectively. It is demonstrated that the model covers important material behavior characteristics, such as the inherent variation of particles’ fracture energy, the influence of their size and weakening of particles due to damage accumulation as well as fines generation due to surface breakage. Differences in the implementation of the model in the different platforms are also discussed, in which Rocky DEM uses polyhedrons to represent particle shape, whereas EDEM favors spheres and clusters of spheres.

The model as adapted in both software platforms has been tested in different size reduction systems. Starting from description of single impacts in which individual particles are propelled against a target and in drop weight tests, in which weakening by repeated impacts is demonstrated, the model has been also validated in breakage of particle beds by comparing the amount of material broken and the size distribution of the progeny. Larger scale comminution equipment are then simulated, demonstrated good agreement between simulations and data.

Prof. Tavares holds a bachelor's degree in mining engineering (1988) and a Master´s degree in Mining, Metallurgical and Materials Engineering (1991) from the Federal University of Rio Grande do Sul and a PhD in Metallurgical Engineering from the University of Utah (1997). He is Professor of the Federal University of Rio de Janeiro and Head of the Laboratory of Mineral Technology of the Graduate School of Engineering (COPPE). He has experience in Mining, Metallurgical and Materials Engineering, with emphasis on Mineral Processing, working mainly in the topics of modelling and simulation of comminution and mineral concentration processes and fundamentals of particle breakage as well as sustainability in the minerals industry. He is a founding member of the Global Comminution Collaborative, has been a member of the editorial board of several scientific journals, including International Journal of Mineral Processing, Minerals, Heliyon and KONA Powder and Particle.  He has presented invited keynote lectures in twelve countries and has been the principal investigators in more than 100 projects.