Abstract In this paper we present some considerations on the computation of optimal flow rates for the heap leaching process of solid reactants from porous pellets. We use a model already published by authors, which is suitable in applications where the scale-up is necessary. This approach allows to obtain better flow rates. Novelty of this approach is the simple form of the models and the easy way to compute good flow rates as used in actual operations in industry, for instance, alternate flows. We propose, also, an exponentially decreasing flow rate which is optimal from the mathematical point of view and the model being used. Due to the model simplicity, they can be used without mathematical complexities. We present a brief sensibility analysis to identify important operation variables that are relevant to change usual constant flow rates of lixiviant agents. Through simple optimization and case studies, we find better flow rate to minimize the acid and water consumed in the process under consideration.