Hydrated lime (calcium hydroxide) is a dry, colorless crystalline powder manufactured by treating calcium oxide (quicklime) with water, in a process called “slaking.” Also known as slack lime, builders lime or pickling lime, hydrated lime is used in the production of mortars, plasters, cements, paints, hard rubber products, petrochemicals, and in the tanning of leather.
A more recent development for hydrated lime use is in environmental applications. Here, hydrated lime, a mild alkali, is used for the removal of acid gases in coal-fired energy plants, cement mills, glassmakers and incinerators.1
However, the largest single use of hydrated lime remains steel manufacturing, where it is used to remove impurities. Hydrated lime is also used to produce other metals. In construction, the dominant use of hydrated lime is in soil stabilization for roads, earthen dams, airfields, and building foundations. Hydrated lime can be used to raise the pH of acidic soils. This is also referred to as soil “sweetening.”2