Modeling single-particle breakage by slow compression

Compression of particles to a fixed final gap is the mode of application of stresses in many crushing devices. Understanding and modeling this particle fracture process is indispensable for comminution operations. The present work is based on detailed compression tests conducted with five different ores to which different deformation ratios are applied to characterize their size-dependent fracture energy distribution and progeny size distribution. An energy-based model is proposed to describe single-particle breakage by compression based on three modes, which define whether the particle is classified for breakage (classification function), the likelihood that the classified particle is sufficiently nipped to break (breakage probability), and the extent of breakage the particle will undergo (breakage distribution). Expressions that allow the calculation of the energy absorbed by the particle in both primary and secondary breakage are proposed by explicitly accounting for particle thickness, stiffness, and the fixed applied final gap. Model verification is demonstrated, with the model predicting the breakage response and energy consumption for single-particle compression experiments performed on a bench-scale with all materials investigated. The validation of the model is shown by accurately predicting, without any fitting, the progeny size distribution and overall energy consumption of compression using fixed gaps and breakage in a double roll crusher.