A three-level Box-Behnken factorial design combining with a response surface methodology (RSM) was employed for modeling and optimizing three operations parameters of the flotation on lead flotation. The flotation studies of lead ores containing 7.1% Pb were carried out in this study. The variables studied were potassium amyl xanthate (KAX) as a collector, sodium sulfide (Na2S) and pH. Experiments were carried out using Box-Behnken factorial design. The main and interaction effects were evaluated using response surface methodology. Second order response functions were produced for both the Ph grade and recovery. These response functions were then optimized using the quadratic programming method to maximize Pb grade and recovery within the experimental range studied. The optimum composition was found to be 212 g/t KAX, 1250 g/t sodium sulfide and 9 pH to achieve the maximum Ph grade. The model prediction of 47.44% Ph at optimum conditions was higher than any value obtained in the initial experiments conducted. In the same way, the optimum composition was found to be 100 g/t KAX, 1250 g/t Na2S and 7 pH to achieve the maximum recovery. The model prediction of 84.58% recovery at optimum conditions was also higher than any value obtained in the initial experiments conducted. (c) 2008 Elsevier B.V. All rights reserved.