Calcium Oxide

CAS #:  1305-78-8

Synonyms: Lime; quicklime; burnt lime; calx; unslaked lime; fluxing lime

Uses: Refractory, flux in steel manufacture, pulp and paper, manufacture of calcium carbide, sulfer dioxide removal from stack gases, sewage treatment ( phosphate removal, pH control), poultry feeds, neutraliztion of acid waste effluents, insecticides and fugicides, dehairing of hides, sugar refining, food additive, glass manufacture, sodium carbonate by Solvay process, carbon dioxide absorbant.  Note: Like other high- melting solids (tungsten, zirconia, carbon), lime (CaO) becomes incandescent when heated to its mp (2500C). Of both historical and etymological intrest is the use of lime as an illuminat in stage lighting for some years before the advent of electricity (1850 -1800). invented in 1816, the technique involved an oxyhydrogen flame  impinging on a cylinder of lime, causing it to emit a brilliant white light that was concentrated to a beam by a lens. the light was powerful enough to spotlight actors or simulate sunshine. it became known in theatrical circles as limelight and was the origin of the familiar phrase “” in the limelight”".

Hazard: Causes burns on mucous membrane and skin.  Inhalation of dust causes sneezing.  A base and an oxidizing agent.  Neutralizes acids with generation of heat. Nonflammable, but will support combustion by liberation of oxygen, especially in the presence of organic materials. Reacts very violently with liquid hydrofluoric acid.  Reacts extremely violently with phosphorus pentaoxide when reaction is initiated by local heating