Abstract The current work has been carried out on a pneumatically fed impact pulveriser. A recent build of the proposed device, and early experiments have shown promising size reduction ratios and energy savings in comparison with conventional milling techniques. A number of experiments have shown the points of greatest wear to be on the blades of the rotor and on the walls of the outlet duct. Experimental work was carried out on a single-phase airflow, and a two-phase air–talc mixture. Numerical simulations were performed using the proprietary CFD code FLUENT. Flow predictions of the single and two-phase systems indicated highly turbulent flows and simulations followed the trends indicated by flow visualisation. The authors propose a breakage model for particles.