Separation of cast and wrought aluminum alloys by thermomechanical processing.
Brown-RD Jr.; Ambrose-F; Montagna-D
Avondale, MD: U.S. Department of the Interior, Bureau of Mines, RI 8960, 1985 Jan; :1-12
There are techniques for separating aluminum alloys from mixed scrap, but there are no efficient ways to separate wrought aluminum from cast aluminum. This Bureau of Mines report describes a novel technique for separating mixed aluminum alloy scrap into cast and wrought aluminum alloy fractions. The technique, which uses conventional heating, fragmentizing, and screening equipment, exploits differences in the mechanical properties of cast and wrought aluminum alloys at elevated temperatures. The cast alloys become brittle at high temperatures owing to intergranular melting of regions of eutectic composition. This melting begins to occur as the solidus temperature for each alloy is reached. Solidus temperatures for casting alloys generally range from 520 deg. to 580 deg. C, but are above 600 deg. C for most wrought alloys. Thus, the casting alloys are easily fragmented while the wrought alloys remain ductile in the proper temperature range. Starting with a mixture containing approximately 80 pct cast and 20 pct wrought alloys, fractions of 100 pct cast and 98 pct wrought have been produced.
Materials-recovery; Metal-scrap; Thermodynamic-properties; Crushing; Size-screening; Separation; Aluminum-alloys
IH; Report of Investigations
NTIS Accession No.
Avondale, MD: U.S. Department of the Interior, Bureau of Mines, RI 8960