Why are molten magnesium and magnesium alloys protected by flux or gas during handling?

Molten magnesium and its alloys must be protected during handling because the metal is highly reactive with oxygen at high temperatures. If left unprotected, molten magnesium can easily ignite and burn with intense heat and a bright white light.1

To prevent this combustion, the metal is shielded by a layer of flux or a protective gas, such as sulfur hexafluoride or sulfur dioxide. This barrier is essential during the refining process, when the metal is melted to remove impurities or to create alloys.2