# 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:*

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

Is it possible to heat the calcium carbonate at temperatures below 825 degrees Celsius.

• Do you mean "Is it possible to achieve the same effect heating the calcium carbonate at temperatures below 825 degrees Celsius?" – G M Feb 10 '14 at 14:54
• Yes, complete calcite at temperatures below 825 degrees Celsius. – marco2008 Feb 10 '14 at 15:58

## 1 Answer

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.

• In the US we activate molecular sieves in a vacuum oven around 150-200 C. In Canada, they use porcelain bowl and a Meeker burner underneath. If nanostructure is important, go cooler. – Uncle Al Feb 10 '14 at 23:10