Demagging processes by fluxing from aluninum alloys

Various aluminum fluoride fluxing treatment were tried to achieve a practical process for demagging from molten aluminum alloys. The tried treatments included pure aluminum fluoride fluxing, aluminum fluoride-open-hearth fluxes mixtures fluxing, and aluminum fluoride fluxing followed by open-hearth fluxes fluxing. Fluxing with mixtures of aluminum fluoride and open-hearth fluxes at temperatures 760 °C or above is the most effective. An effect of initial Mg concentration in aluminum alloys on demagging efficiency is determined. An antipollution demagging process using silica (U.S. Pat. 4,097,270) was also tested. It is not so applicable economically and has a low and unstable demagging efficiency.