Calcium hydroxide, also known as slaked lime or hydrated lime, is typically produced from limestone through a process called slaking. Here are the steps involved:
Quarrying: Limestone is extracted from quarries and transported to a processing plant.
Calcination: Limestone is heated to a high temperature (around 1000°C) in a lime kiln to produce calcium oxide (also known as quicklime). This process is called calcination and drives off carbon dioxide from the limestone, leaving behind calcium oxide.
Slaking: Quicklime is then mixed with water in a process called slaking. The water causes a chemical reaction that produces calcium hydroxide:
CaO + H2O → Ca(OH)2
The reaction is exothermic and produces a lot of heat.
Purification and Drying: The calcium hydroxide is then purified to remove impurities and excess water. This is typically done using a rotary kiln or a vertical kiln. The purified calcium hydroxide is then dried to remove any remaining moisture.
Packaging and Storage: Finally, the calcium hydroxide is packaged and stored in bags or bulk containers until it is ready to be used.
Overall, the production of calcium hydroxide from limestone involves the use of high temperatures, water, and careful handling of the materials to ensure worker safety. The process is widely used in various industrial applications such as water treatment, construction, and agriculture.