Interfacial Tension between Aluminum and NaCl-KCl-Based Salt Systems

摘要

Aluminum scrap is frequently remelted under aNaCl-KCl based salt flux cover to prevent oxidation, to aid in thestripping of oxide films, and to improve drop coalescence. In thisprocess, the interfacial tension between the aluminum metal andthe salt flux plays and important role. However, the measurementof interfacial tensions at high temperature is difficult and prone toerrors. Therefore, an interfacial tension model, presented in thisarticle, has been developed. The interfacial tension betweenaluminum and NaCl-KCl based melts does not change with theaddition of chlorides or with variations in the composition of theNaCl-KCl melt. On the other hand, the addition of fluoridesdecreases the interfacial tension to various extents due to theadsorption of sodium and/or potassium at the interface. Additionof AlF3 is the least effective; addition of LiF, MgF2, CaF2, BaF2,or SrF2 are moderately effective; and addition of NaF or KF arethe most effective in lowering the interfacial tension.