IST16 User manual
–
Version 8.0
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INSTRUMENTS
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16.3
Results
16.3.1
TGA/DSC
Figure 1 displays the TGA results using the 70 µL alumina crucible of around 10 mg of calcium carbonate.
The method consisted of a heating from 500 °C to 1000 °C at 20 °C/min. Nitrogen was used as protective
and reactive gas at 20 mL/min and 30 mL/min flow rate, respectively.
The TGA curve normalized to the initial sample mass is shown in black and the DTG curve is shown in red.
The DTG curve corresponds to the first derivative of a TGA curve. In a DTG curve, a TGA step is displayed as
a peak. This makes it easier to determine the limits for the TGA step evaluation.
The sample exhibits one decomposition step of about 44 % in the studied temperature range under
nitrogen atmosphere. It starts at about 600 °C and has its maximum slope around 780 °C. The measured
mass loss of 44 % for the calcination of calcium carbonate agrees well with the expected mass changes.
From the stoichiometry of the reaction (CaCO
3
→
CaO + CO
2
), the theoretical calculated weight loss is 44 %.
The effect observed at about 900 °C corresponds to IST16 position change from storage mode to injection
mode (after collection of the last loop) and is not related to a thermal effect.
Figure 1
: TGA and DTG curves
