Thermal Decomposition Of Two Tunisian Natural Phosphates And Study Of Kinetic Decarbonation

We propose in this work to study thermally the decomposition of two Tunisian natural phosphates or carbonated fluorapatite in a range of temperature between ambient and 1000C. Several techniques were used such as thermo gravimetric analysis differential scanning calorimetry and Infra-Red Spectroscopy for this mineralogical study. The results showed that after dehydration decarbonation occurs in two steps. In the first one the maximum decomposition rate appears near 660C for the sample of phosphate 1 and 770C for the sample of phosphate 2. In the second one the maximum is about 780C for phosphate 1 and 810C for phosphate 2. In addition it was reported that the first decarbonation translated the kinetics of decomposition of the carbonate ions of the type B associated with a vaccum while the second decarbonation is related to the thermal decomposition of the entity of CO3F generated by the decomposition of carbonate ions of type B and A.