In order to investigate the difference in flotation kinetics of various size fractions of bituminous coal between rougher and cleaner flotation processes, clean coal was collected as a function of time in both rougher and cleaner flotation processes. The size composition of clean coal was then analyzed. Six flotation kinetic models were applied to the modeling of data from the flotation tests by using MATrix LABoratory software. The relationship between flotation rate constant, maximum combustible recovery and particle size was also studied. The results show that the maximum flotation combustible recovery and flotation rate are obtained with an intermediate particle size both in the rougher and cleaner flotation processes. The combustible recovery and flotation rate are higher in the cleaner flotation process than that in the rougher flotation process. Except the classical first order flotation kinetic model, the other five kinetic models gave an excellent fit to the flotation data. The rougher flotation process can be described using the first-order and second-order models while the cleaner flotation process can only be described using the first-order model. It is found that the first-order model with rectangular distribution of floatability provides the best fit of the experimental data obtained from both the rougher and cleaner flotation processes-among the tested models. (C) 2016 Elsevier B.V. All rights reserved.