DETERMINATION OF OXYGEN IN CALCIUM METAL BY DISTILLATION AND ANALYSISOF THE RESIDUE

Calcium is a very reactive metal and always contains some oxygen, alth ough it is generally stored under inert gas. Specific applications req uire the evaluation of the oxygen content of calcium metal by a method reliable enough for industrial purposes. The standard method based on high temperature reduction of the oxide by carbon is dangerous becaus e of reactive calcium deposits in the equipment, introducing a fire or explosion hazard, mainly during cleaning. In this paper, a method is described based on distillation and analysis of the residue. Samples ( 150-300 g) must be ground under argon. Distillation proceeds under Vac uum at 940 degrees C for 3 h. The residue free from metal is crushed u nder argon. A small amount of it (3 mg) is submitted to oxygen analysi s in a conventional LECO atmospheric pressure oxygen analyser.