2.3. Chemical analysis
The elements were determined by X-ray fluorescence Spectrometer (XRF) method following the procedures of Goto and Tatsumi [7] using Rigaku ZSX Primus XRF machine equipped with an end window 4 kW RH-anode X-ray tube.
Differential thermal analysis (DTA) technique was used to study the thermal behavior of the raw material at a heating rate of 10 °C/min by using SII EXSTAR 6000.