Samples of the input, output and return material of cement clinker are collected and analyzed from an industrial CKP mill. The model of first-order crushing rate function is established and all the parameters are suitable for physical characterization by using the data of the material size distribution and mass balances. The values of three parameters b, mu and gamma are identified as -0.3263, 15.2 mm and 2.59. The relationship between the parameter a (min(-1)) and the operating parameters in the CKP mill is determined by the correction model. When the total grinding flux in the CKP mill reaches 88 t/h, the parameter a (min(-1)) has a local maximum. Using the fitting method and curve data compression principle, the best operating area of the industrial mill is calculated under different circulating loads. These results provide the basic mechanisms for energy conservation and emissions reduction of actual production practice in industrial mills. (C) 2013 Elsevier B.V, All rights reserved.