It is necessary for calcium oxide (quicklime) to be slaked in a controlled environment because it can create heat that reaches up to 50 degrees Celsius. Calcium hydroxide, or hydrated lime, is already neutralized, so it will not undergo oxidation and can be mixed with water in our system, for water ph control, lime slurry addition, lime slurry mixes, soil rehabilitation and more.
The fact of adding water to the powdered quicklime, putting it in a kiln or oven, and then pulverizing it with water, lead to the reaction of CaO with H2O bringing the new chemical Ca(OH)2.
CaO + H2O→ Ca(OH)2