Analysis of Composition, Properties, and Usage Efficiency of Different Commercial Salt Fluxes for Aluminum Alloy Refining

One of the key problems in the billet and shaped casting of aluminum alloys is the presence of various undesirable inclusions and impurities in the melt, which can serve as stress concentrators in the finished product, as well as dissolved hydrogen, which contributes to the formation of porosity. The interaction of aluminum with other gases produced by the combustion of fuel particles, oil, and paint materials brought into the furnace together with charge and scrap increases the amount of nitrides, oxides, carbides, and sulfides in the melt. Flux treatment is widely used as protection of aluminum alloys from oxidation and removal of impurities. The present paper reports the data of a comparative analysis of five widely used flux compositions based on sodium, potassium, and magnesium chlorides. The study covers the following aspects: chemical composition, moisture content, melting temperature and melting range, particle size distribution, and refining ability as measured by the change in Na, Ca, and H2 content after melt treatment.