Improving aluminum recycling through investigations of thermodynamic effects in remelting

Aluminum recycling is an important area of research because of the tremendous energy savings achieved by producing aluminum products from secondary sources. Aluminum products have precise compositional specifications that must be met to ensure adequate mechanical properties. These precise compositional specifications limit the incorporation of secondary metals into final aluminum products because of the substantial compositional uncertainty of secondary materials. Reducing the amount of compositional uncertainty in secondary metals streams is an active area of research because of the projected gains in scrap utilization. One potential source for compositional uncertainty during scrap remelting is thermodynamic reactions involving aluminum and the secondary alloying elements in the melt. This paper explores the chemical reactions that may occur during aluminum remelting and the resulting impact on material yield. The conclusions from this investigation will aid the development of higher accuracy batch planning algorithms that incorporate the thermodynamic effects on material yield and thereby promote scrap utilization.