Chlorine Control by In-Line Fluxing Operations

Abstract

The history of the metallurgy of aluminum and its alloys has been closely associated with chlorine and fluorine. Fluorine is important in smelting operations. This paper deals with melting operations and discusses the use of chlorine to remove aluminum and magnesium oxides, dissolved hydrogen, and minor elements such as sodium and magnesium to obtain aluminum alloys of a quality satisfactory for modern use in transportation, aircraft, building, and other industries. A development period of ten years has resulted in a series of graded processes that accomplish this chlorine use effectively enough that atmospheric contamination is no longer a problem. The use of these processes which operate between the melting and casting units is discussed in some detail. The use of a new process to remove magnesium from recycled scrap aluminum is also considered.