Civil Engineering Reference
In-Depth Information
as the rice husk ash has also been studied by thermal analysis.
[28]
Lithium
carbonate is used to lower the decomposition temperature of calcium
carbonate in the reaction of CaCO
3
with quartz. DTA-DTG of mixtures of
CaCO
3
and quartz containing different amounts of lithium carbonate
(equivalent to 0.1-5% Li
2
O) was examined up to a temperature of 1450°C.
[29]
The decomposition temperature of calcium carbonate was lowered as the
amount of lithium carbonate was increased. The CaO formed from the
decomposition of the carbonate, combined with SiO
2
to form C
2
S. At 1%
Li
2
O,
-C
2
S was detected even at a temperature of 750°C, but the reaction
was completed only at 1350°C. At an additional level of 5%, the final
reaction temperature decreased to 1250°C. In terms of the decomposition
of CaCO
3
, at Li
2
CO
3
contents of 0.5, 1, and 5%, approximately 2, 6, and
80% CaCO
3
decomposed at about 600°C.
β
Figure 7.
DTA of calcium carbonate-silica containing fluorides.
