Lithium carbonate-containing pellets were made in a laboratory-scale centrifugal granulator in order to investigate the effects of the process parameters (rotor rotation speed, slit airflow rate and spray air rate) on the pellet shape and size distribution. The size distribution and the shape parameters (roundness, roughness, rectangularity and sphericity) of the pellets were measured, and an optimization parameter was then calculated from these shape parameters. The experiment was carried out and evaluated according to a 2(3) full factorial design. All three variables were found to exert a significant effect on the pellet shape. With use of the signs and magnitudes of the coefficients of the variables in the fitted linear model, the direction of the gradient was determined; two control measurements were made. These proved the accuracy of the applied model and the direction of the gradient. Overall, a high rotor rotation speed and low slit airflow rate and spray air rate furnished the best value of the optimization parameter.