Lime works. Industrial plant for the treatment of the quarried mineral limestone. Limestone is calcium carbonate (CaCO3), which is an important building material, being used as an aggregate in road construction and a ballast for railways. It is also the source of quicklime (calcium oxide), which is made by heating to 800 degrees Celsius: CaCO3 ----> CaO + CO2 Quicklime is used in making mortar and cement. When mixed with water it produces slaked lime, or calcium hydroxide (Ca(OH)2). Slaked lime is used in agriculture to neutralise acidic soil.