An application of breakage mechanics for predicting energy–size reduction relationships in comminution

• Stress and evolving size distribution during comminution are linked in a new continuum modelling.
• The evolving size distribution can be tracked in space and time during comminution.
• This study opens a new potential for optimising grinding operations.

We propose a new continuum approach to predicting the energy–size reduction relationship in comminution. The approach is based on a breakage mechanics model that accounts for the evolution of the grain size distribution (GSD) due to comminution with only five parameters, all of which are physically meaningful. The model is implemented and used in finite element analysis to study the energy–size reduction relationship in a roller mill. Predictions of product GSDs and energy consumption are validated against experimental counterparts. On this basis, a series of parametric studies in terms of various roller gaps and grinding speeds are carried out in order to explore: 1) the optimum roller gap, in which the maximum new surface can be created while the least input work is required; and 2) the influence of increasing grinding speeds on new surface creation.

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