Calcium Oxide Preparation Calcium oxide is called quick lime. It is prepared by heating limestone in a rotatory kiln at 1070-1270 K. CaCO3 ⇔ CaO + CO2 ΔH = 179.9 KJ Since the reaction is reversible, therefore, the carbon dioxide is removed as soon as it is formed to enable the reaction to proceed to completion. The temperature is not allowed to rise above … [Read more...] about Calcium Oxide