Mathematical Modeling of the Dissolution of Phosphate Rock into Various Acidic Medium

The leaching of phosphate ores in acid medium is widely practiced in the chemical fertilizers industry. Several processes can take place in the reactor and the quantitative modeling of the reaction kinetics or thermodynamics is essential for the design and dimensioning of the industrial equipments. The aim of the present study is to develop a mathematical model to describe the behavior of phosphate particles into acidic solution under certain conditions. A new formalism based on the Noyes-Whitney equation (NWE) is presented in this paper. In this approach, simplified Lucas-Washburn's equation (LWE) is incorporated to evaluate the progression of reaction zone into the mesoporous phosphate rock. The reliability and validity of this new approach are tested on a large database. Results show that the model is predictive in the case of a solid dissolution without ash film and non predictive in the case of solid leaching with formation of a rushed in the mesoporous area follows. Furthermore, the values and physical significance of the parameters of this model are also discussed in the present work.