Degassing of magnesium alloy by rotating impeller degasser: Part 1 – Mathematical modelling

Abstract

A mathematical model was used to simulate the removal of hydrogen from magnesium alloy by a rotary impeller. It has been shown that the degassing efficiency is mainly dependent on the total surface area of the inert gas bubbles that is related to the rotation speed and the gas flowrate as well as the design of the impeller. An oxygen/water system was used to determine the total surface area of the inert gas bubbles experimentally. Finally, degassing experiments were carried out on magnesium melt to verify the mathematical model. Excellent agreement was obtained between the model predicted and the measured degassing efficiency. It was concluded that this model and the oxygen/water system are suitable to predicate the removal of hydrogen from magnesium alloy by the rotary impeller, and are also useful to the design of the impeller and the research of the effect of the processing parameters.