An experimental study of the impact breakage of wet granules

The breakage behaviour of wet granules produced in a high-shear mixer was investigated experimentally using single granule impact tests and the results are described in terms of the critical impact velocity, breakage pattern, and extent of breakage. The failure patterns of these wet granules have a number of common features that have been observed for dry granules including the formation of debris with a conical geometry. A more quantitative description is presented of the factors that control the volume of these conical regions. The granules were produced with negligible air voidage and there were unusual strength characteristics with varying binder content. Most previous studies have involved a reduction in the air voidage of granules as the binder content is increased, which leads to a maximum in the strength at some critical binder content. For the granules studied in the current work, the strength either showed a minimum value or decreased monotonically with increasing binder content depending on the size of the primary particles.