Quicklime, chemically known as calcium oxide (CaO), is a white powder or solid substance produced by high-temperature calcination of natural limestone (primarily composed of calcium carbonate). During the calcination process, calcium carbonate in the limestone decomposes into calcium oxide and carbon dioxide gas. Quicklime is strongly alkaline and hygroscopic, capable of undergoing a vigorous chemical reaction with water to form calcium hydroxide (commonly known as slaked lime or limewater), releasing a significant amount of heat in the process. As a desiccant that removes water vapor through chemical absorption, quicklime is commonly used in industries such as steel production, pesticides, pharmaceuticals, leather tanning, and alcohol dehydration.