The fundamental research on suspended dross in hot dip Al–Zn galvanising process

Abstract

In this research, supergravity enrichment experiment was conducted to determine compounds in suspended dross and to analyse density of the suspended dross in the hot-dip Al–Zn (ZA) melt. It was found that the suspended dross was composed of Al–Fe–Si–Zn intermetallic compounds (IMCs), mixtures of Fe2Al5Zn0.4 and Alx–Fe3–Siy with various Al and Si contents. The density of suspended dross was small compared with the molten hot-dip ZA liquid. After being quenched in water, the morphology of the suspended dross was confirmed as polygonal granular structures. Thermodynamics was applied to explain why there were various morphological structures of the suspended dross in the solidified hot-dip ZA melt. This research had also demonstrated that it was technically feasible to separate the suspended dross from the molten hot-dip ZA melt in a supergravity field.