What is Air-Slaked Lime? Uses, Properties, and Applications

Air-slaked lime, also known as "unslaked lime", is a type of calcium oxide (CaO) that has not been slaked, or mixed with water, to form calcium hydroxide (Ca(OH)2). Slaking is the process of adding water to calcium oxide to produce calcium hydroxide, which is the main component of lime putty.

Air-slaked lime is made by heating limestone (calcium carbonate, CaCO3) in a kiln or furnace without adding any water. The high heat causes the limestone to decompose into calcium oxide and carbon dioxide, leaving behind a powdery residue that is air-slaked lime. This process is called "calcination".

Air-slaked lime has several applications, including:

1. Construction: Air-slaked lime is used as a binder in cement and concrete, as well as for plastering and rendering walls.
2. Agriculture: Air-slaked lime can be used to neutralize acidic soil and improve its fertility.
3. Water treatment: Air-slaked lime can be used to remove impurities from water by precipitating them as calcium carbonate.
4. Paper manufacturing: Air-slaked lime is used in the production of paper to improve its strength and durability.
5. Pharmaceuticals: Air-slaked lime is used as an ingredient in some pharmaceutical products, such as antacids.

Overall, air-slaked lime is a versatile product with many applications in different industries.