Complex Permittivity of Moroccan Phosphate as Function of Moisture Content

Abstract

This paper deals with the experimental results of hertrian spectrum analysis of phosphate as function of moisture content. A study has been developed in the microwaves frequencies range the results of this study has been used to built a moisture rate controller. I -IntroductionThe phosphate, when extracted from mines has a moisture content of about 17 %. The drying reduces this rate at 1 %. The great problem lies in the measurement of this last parameter.In order to reach an optimal control [iJ of phosphate drying furnace, we have done a deep study [2] . In this study we investigated all the physical parameters that could be developed in measuring residual humidity of phosphate coming out of a drying furnace. In this paper we study especially dielectric properties. This physical parameter is the only one that seems intersting for the humidity control of phosphate. The other parameters, which have been tested with some success in laboratory C33 , are not, as far as we know, suitable to an industrial use, except back-warddiffusion of infra-red rays that, we think will give satisfactory results £43. II -Dielectric properties of phosphateWe have done a study of dielectric properties of phosphate from a few Hz to 20 GHz in collaboration with other laboratories >J , L 6 J . The experimental method to obtain the dielectric spectrum of phosphate is described elswhere £21 . It is based on a measure of the complex permittivity, given by:Which can be writtenWhere tg6 = s" e' is the dielectric losses.The moisture rate is defined as follows PH -PS h % -P-PSx 100 PH Where PH and PS are respectively the humid and dry sample weight.