Quicklime, often referred to as either calcium oxide (CaO) or lime, is manufactured by heating the raw ingredient ‘limestone’ or ‘calcium carbonate’ in large kilns. This process removes CO2 that is trapped in the stone leaving behind CaO and other minor mineral constituents. This CaO molecule is what we consider to be high calcium quicklime.
Quicklime as CaO is not the most useful chemical form for many applications. For applications such as water treatment, flue gas treatment, and when used as a raw ingredient to some chemical applications, the quicklime must first be slaked. Slaking occurs when quicklime is reacted with water to form Ca(OH)2, most commonly called hydrated lime in its dry form or lime slurry or milk of lime in its wet form. The slaking process is exothermic, releasing heat as the quicklime and water mix and chemically combine. A lime slaking system that is not running at its peak could be unsafe, cost you money and potentially shut your process down.