A solid, white (when pure), highly infusible caustic, a constituent of the chemical calcium oxide (CaO), made by calcining limestone, shells, or other sources of calcium carbonate. Lime is a byproduct of acetylene, generated by dropping calcium carbonate into water. The chemical reaction is:
CaC2+ 2H20+C2H2+ Ca(OH)2
See QUICKLIME.
The temperature of acetylene generation often causes a quantity of carbide lime to be carried by the gas. This lime dust passes freely through water; the quantity is small and can be easily removed by a chemical purifier. Its effect on welds seems negligible,
although there have been incidental reports that the narrow passages of some regulators or torches are affected.