The batch flotation process has been commonly characterized assuming a flotation rate distribution function F(k), e.g.: Dirac delta, Rectangular, Gamma or Weibull functions. The identification of F(k) for the collection zone of continuous industrial cells is more complex and to the authors knowledge, has not been reported yet. In this work, a novel procedure to estimate the flotation rate distribution from the collection zone of industrial flotation cells, using the radioactive tracer technique, is presented. The approach consists of measuring the impulse response of the floatable mineral tracer concentration, and non-floatable gangue tracer concentration (Residence Time Distribution, RTD), in the cell tailings. Then, the floatable tracer concentration can be compared with the model prediction, using the Gamma function and the RTD of the non-floatable tracer. Thus, the F(k) distribution parameters were obtained by means of the least-square estimation. The new approach was successfully tested in industrial rougher flotation cells of large size. (C) 2010 Elsevier Ltd. All rights reserved.