A modified Rittinger model for the grinding of wet granular material

Grinding is a fundamental process widely used across various industrial sectors. Although often considered merely a pre-treatment step, it remains poorly studied from a fundamental perspective-especially when accounting for the presence of water or humidity. In particular, the relationship between grinding parameters and size reduction efficiency remains a critical bottleneck in optimizing this highly energy-intensive operation. The water content of the raw material to be ground is often a poorly controlled factor, yet it strongly influences grinding efficiency. This can be due to lubrication forces and capillary cohesion, which leads to the formation of aggregates that are more difficult to grind. This paper presents an original approach to link the particle aggregation capacity with the grinding rate. This aggregation, which limits the energy available for effective grinding, was estimated using the Carr index. A modified Rittinger law that relates the specific surface area created to the energy transmitted by the grinding media, incorporating the influence of water content is proposed. This model provides new guidelines for achieving more efficient comminution. • Quartz sand grinding, performed in a vibratory ball mill on dry to saturated samples • Grinding rate shows strong correlation with densification capacity of a granular bed • A modified Rittinger model: incorporating water content through the Carr index