In the USA aluminum accounts for 99% of the beverage can market and over 85% of aluminum cans are recycled. An important step in recycling is adjustment of alloy composition (e.g., magnesium removal) by "chlorine fluxing". Argon/chlorine mixtures are bubbled through the molten alloy to react with constituents to be removed. Chlorine emissions are common. This is a fundamental study, by experiment and mathematical modeling, of the phenomena (reaction kinetics, mass transport and bubble behaviour) governing this technology.