Calcium Carbonate

DESCRIPTION

Calcium carbonate (CaCO3), chemical compound consisting of one atom of calcium, one of carbon, and three of oxygen that is the major constituent of limestone, marble, chalk, eggshells, bivalve shells, and corals. Calcium carbonate is either a white powder or a colorless crystal. When heated, it produces carbon dioxide and calcium oxide (also called quicklime). Calcium carbonate has many uses. Since ancient times, limestone has been burned to quicklime (CaO), slaked to hydrated lime [Ca(OH)2], and mixed with sand to make mortar. Limestone is one of the ingredients used in the manufacture of portland cement and is often employed as a flux in metallurgical processes, such as the smelting of iron ores. Crushed limestone is used widely as riprap, as aggregate for both concrete and asphalt mixes, as agricultural lime, and as an inert ingredient of medicines.