Because molten magnesium burns in the presence of oxygen, production and casting of magnesium metal requires a protection system to prevent this oxidation. Among the various protection systems commonly used are those that use gaseous components with high GWP values, such as SF6, which typically escape to the atmosphere. SF6, because it is such a non-reactive gas, is ideally suited for this kind of protection as a covering for molten magnesium (hence the term “cover gas”).
Shanghai Meridian Magnesium Products (SMMP) currently uses SF6 as a protective cover gas to prevent oxidation of its molten magnesium. The proposed project will switch over from SF6 to either sulphur dioxide or another gas called Novec-612. The project will stop using the SF6 and instead use a cover gas that has no global warming potential, thus reducing GHG emissions to the atmosphere.