Milk of lime is produced by slaking of quicklime with excess water. Lime Slaking is done in both batch and continuous slakers. The term milk of lime is used to describe a fluid suspension of slaked lime in water. It may contain up 18-40% by weight of solids. Milk of lime with a high solids content is sometimes called lime slurry. 

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 Milk of Lime is a fine suspension of calcium hydroxide particles in water and as the term implies is visually, but certainly not chemically, similar to your everyday pint of milk. Calcium hydroxide is produced from the highly exothermic reaction between calcium oxide, known also as “burnt lime”, and water as shown below. An excess of water is added to keep the calcium hydroxide in liquid suspension and to control the percentage solids content.

 

CaO + H2O → Ca(OH)2

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Operational control is maintained by computerised, measured additions of specialist chemicals to the process water. The treated water and burnt lime are then metered independently into the first of three stirred mixing vessels, otherwise known as slakers, where the exothermic chemical reaction begins. Resultant liquid hydrated lime product passes through two more mixing and conditioning vessels before it is screened to remove oversized grit and pumped to one of five holding tanks ready for despatch/usage.