Quicklime, also known as calcium oxide, is a white, caustic solid that is produced by heating limestone in a process called calcination. This process removes carbon dioxide from the limestone, resulting in quicklime. It is commonly used in various industries, including construction, where it serves as a key ingredient in making cement and mortar. In addition to construction, quicklime has applications in water treatment, where it helps to purify drinking water by removing impurities. It is also used in the production of glass and in the chemical industry for various reactions. Due to its reactive nature, quicklime must be handled with care.