The kinetics of the thermal decomposition of natural moroccan and iraqi phosphates

Abstract

Phosphate rock valorization aims by thermal treatment to eliminate humidity, organic matter and carbonate in order to increase the amount of P 2O 5. This work consists in the study of both Moroccan and Iraqi phosphates by thermogravimetry, for differents particle size such as 0–200μm, 200–315μm, 315–500μm, 500–800μm, in argon, oxygen and air. The thermal decomposition curves present between the ambient temperature and 1000°C show three domains of weight loss. These are assigned to dehydration (20–200°C), elimination of organic matter (200–550°C), and decomposition of carbonate (600–850°C) respectively. The effect of particle size and the nature of transport gas on thermal decomposition have been investigated. On the other hand, sample phases have been studied by xrd before and after heating. Activation energy(E) and frequency factor(k o) attributed to phosphate decomposition have been determined by FREEMAN-CARROLL methods.