1997 Volume 83 Issue 3 Pages 187-192
Based on studies of the electrochemical stability of the intermetallic compound (Al-Fe-Si-Zn) in a 55mass% Al-Zn bath, a method of isolating and identifying the composition of the dross was established.
The dross was extracted by controlled potential electrolysis at-1.4V vs. SCE in a 10mass% NaOH solution. A small amount of residual Zn was removed by dissolving with concentrated HNO3. The extracted dross was dissolved in HCl and the amounts of Al, Fe, Si and Zn were determined by ICP-AES. The concentration and chemical composition of the dross in rapid-cooled and air-cooled samples were almost equivalent.
The method of controlled potential electrolysis in an NaOH solution was also found to be applicable to the removal of the upper layer of 55mass% Al-Zn plate for electron microscope observation of the alloyed layer (Al-Fe-Zn-Si intermetallic compounds).
