Drying phenomenon of Moroccan natural phosphates under microwave irradiation. Part I: Thermal and kinetic aspects

In this paper, the use of microwave energy in a drying problem is examined. The purpose of this work is the investigation of the effect of incident microwave power to a material during drying and in particular the research of the experimental conditions which can be used to accelerate the drying phenomenon in order to save energy in the industrial processes. We describe, in the first instance, the experimental apparatus used and the results of kinetic and thermal aspects of drying induced by microwave heating. These results lead to the role of different parameters (microwave power, initial sample mass and diameter of the reactor) on the kinetic and the thermal aspects of the drying. In the second instance, the experimental results are presented and discussed taking into account the dielectric proprieties of the material, the literature and the use of the heterogeneous kinetic models. These studies point out important kinetic and thermal aspects allowing a better understanding of drying under microwave irradiation.