This paper aims at the determination of the kinetics and thermodynamics of a liquid-solid reaction: the attack reaction of the phosphate ore by sulphuric acid. This reaction, which is used industrially for the production of phosphoric acid, has two stages, the first of which consists in the dissolution of phosphate ore in the diluted phosphoric acid diluted and the second relates to the attack of the dissolved ore by sulphuric acid. The thermodynamic properties and the kinetic parameters of each reaction are determined using a calorimetric approach. The complete kinetic study of the step in dissolving the phosphate ore was conducted to develop a kinetic model involving the process of transfer kinetic liquid-solid and the chemical kinetic processes. This model takes into account the coupling between the mass and heat balance and the multitude particles' sizes of phosphate and the stirring speed. The study of the attack of monocalcium phosphate by sulphuric acid allows the evaluation of the reaction order and the values of various parameters that describe the kinetic model of the precipitation reaction. The comparison of different parameters determined with those reported in the literature shows the reliability and the relevance of the proposed methodology.