Quicklime, a monoxide of calcium (CaO), is often referred to as burnt lime. It is a white, caustic, alkaline, crystalline solid manufactured from limestone, which is extracted from quarries and mines. Limestone is usually crushed and fed into lime kilns, where it is burned at high temperatures and broken down into calcium oxide and carbon dioxide.

Quicklime has a wide range of uses, including in the production of iron and steel, paper and pulp, sugar refining, water treatment, flue gases treatment , agriculture, mining, etc.