The use of magnesium, the lightest metallic construction material, is on the rise – above all in the automotive industry. To lower the attendant risk of a magnesium fire triggered by oxygen, sulfur hexafluoride (SF6) or sulfur dioxide (SF6) have been used to date. Sulfur dioxide is toxic and therefore subject to rigorous safety precautions when used in foundries. Sulfur hexafluoride, in turn, has a high global warming potential or GWP factor of 23,900 – with respect to the damage caused to the earth’s atmosphere by CO₂. The use of sulfur hexafluoride for cast magnesium has therefore been banned with effect at January 1, 2007, unless the quantity involved remains below 500 kilograms per annum.

Linde Gas has developed and filed a patent for a procedure that eliminates these problems. Using dry ice as a covering agent and protective gas, magnesium melts are effectively shielded from the ingress of oxygen.