Thermal analysis (DSC-TG-MS) - Senegal phosphate ore with additives - uncalcined and calcined samples

Samples of phosphate ores from Senegal deposit with additives (NaCl, KNO3, Na2CO3) before and after calcination process were subjected to differential scanning calorimetry and thermogravimetry coupled with mass spectrometry (DSC-TG-MS).
All samples used in this study prior to any experiments were air dried under ambient conditions, then ground in IKA A11 Basic analytical mill and sieved to fraction less than 300 μm.
Samples of phosphate ore from Senegal deposit were mixed with solid NaCl, KNO3 and Na2CO3 in 19:1 (m/m) relation. The mixtures were then calcined in porcelain crucibles in the FCF 12 SHM resistance muffle furnace at the temperature (850°C, 950°C, 1050°C) and calcination time (1 h, 2 h, 3 h) according to the experiment matrix of full factorial design plan. Approx. 10 g of sample was placed in the crucible which was inserted to a preheated oven, kept for the selected time, then removed and cooled in a desiccator.
The thermal analyzer Netzsch STA 449 F3 Jupiter, with thermobalance and the quadrupole mass spectrometer Netzsch Aeolos QMS 403C, was used. Sample containing 20 mg of studied material was placed in a 85 μl DSC crucible made of alumina, and then heated to a temperature of 1100°C with a heating rate of 10°C/min in synthetic air with a total flow of 30 ml/min. Measurements were preceded by correction measurement up to 1200°C to compensate thermal effects associated with characteristics of the crucible.

This research was funded by National Science Centre, Poland under research project „Badania oczyszczania surowców fosforowych z kadmu przez kalcynację”, no UMO-2021/41/N/ST8/00147.