The protection of molten magnesium by SO_2 gas mixtures

摘要

The gas flow and the sulphur dioxide concentration needed for a sufficient melt protection depend on the alloy, the melt temperature and the furnace design. At high melt temperatures protective gas mixtures consisting of N2, CO2 and SO2 are superior to ones consisting of N_2 and SO_2. Gas mixing units ensure constant gas concentration In protective gas mixtures and enable adjustments of the gas flow and the gas concentrations to existing process conditions. Measurement of the gas concentrations in a furnace helps to investigate the causes of excessive dross formation. It is also a valuable tool for the adaptation of the gas flow and the sulphur dioxide concentration in protective gas mixtures and in optimisation of the furnace design.