In this study, the dissolution kinetics of synthetically prepared CaWO4 in HCl solutions containing H3PO4 was studied. The effects of process parameters such as stirring speed, temperature and acid concentrations on the dissolution rate of CaWO4 were investigated. The reaction rate was found to be of 1/3 and 2/3 order with respect to HCl and H3PO4 concentrations, respectively, and the activation energy for the dissolution reaction to be 60 W mol(-1). The rate equation for the dissolution reaction was derived using the Avrami equation and the rate determining step was the chemical reaction on the surface of solid particles. (c) 2005 Elsevier B.V. All rights reserved.