DRYING PHENOMENON OF MOROCCAN NATURAL PHOSPHATES UNDER MICROWAVE IRRADIATION Part Ⅱ: Comparative studies with drying by conventional heating

摘要

In this article, we present parallel studies on the structural, textural and morphological aspects as well as on the kinetic mechanisms of drying natural humid phosphate by conventional heating and by microwave irradiation. Experiments of drying under atmospheric pressure and under controlled temperature and incident microwave power, have been realized in the isothermal and non-isothermal regimes either in a programmable electrical oven or in a specially adapted microwave cavity. Analysis of samples was performed by various techniques: X-ray Diffraction, Scanning Electron Microscopy, Infrared Spectroscopy and BET method. The experimental results obtained under microwave irradiation are discussed and compared with these obtained by conventional heating. These comparative studies allowed to situate the action of the microwave field and compare it with the classical heating.