Thermal decomposition of calcium carbonate Thermal decomposition of calcium carbonate.

In general, we heat $\ce{CaCO3}$ to temperature of approximately 825°C it decomposes into calcium oxide and liberates carbon dioxide gas:*

$$\ce{CaCO3} \overset{825\ ^\circ \text{C}}{\ce{ -&gt;}}\ce{CaO + CO2}$$

Is it possible to heat the calcium carbonate at temperatures below 825 degrees Celsius.
Pump a hard vacuum and calcium carbonate will calcine at a lower temperature.  825°C is about one atmosphere of carbon dioxide at equilibrium.  Thermodynamics proposes, kinetics disposes - finely ground goes faster than bulk.