The effect of impeller speed and cell volume on batch coal flotation performance in a self-aerating flotation machine is studied in the present investigation. Factorial designed experiments are carried out to establish the relationships between the manipulated variables (impeller speed, and cell volume, and their interactions) with the separation indicators (yield, ash, combustible recovery and entrained water recovery). Correlation coefficient values are used to select the best fit model, and an analysis of variance to identify the statistically significant components of the model. The results indicated that both the impeller speed and cell volume significantly influence the performance of coal flotation. Further, the influence of these variables and their significance is discussed by flotation rate constant. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved.