The paper examines the various factors that influence the breakage of particle agglomerates resulting from impact. Numerical simulations of polydisperse spherical agglomerates impacting orthogonally on a target wall have been performed to study the effects of impact velocity, solid fraction, contact density, and the local arrangement of particles near the impact zone. Results of simulations show distinct fracture patterns for dense agglomerates above a critical impact velocity whereas for loose agglomerates disintegration occurs under identical testing conditions. Either fracture or disintegration may occur for agglomerates with an intermediate packing density. It is also demonstrated that, for agglomerates with intermediate packing densities, the mode of failure can change from disintegration to fracture by either increasing the contact density or changing the location on the agglomerate surface, which is used as the impact site. (C) 2001 Elsevier Science B.V. All rights reserved.