Abstract (EN):
The effect of structural composition on the purification of Fe-Si alloys by acid leaching is analyzed. Two alloys with different phase constitution were studied: industrial ferro-silicon, with a high Ca/Al ratio containing a quaternary phase Fe-Al-Si-Ca (Caalsifer) together with FeSi2 phases; and a laboratory prepared alloy in which the high Al content induces the precipitation of Al-Fe-Si phases preferably to Caalsifer, and hinders the formation of tetragonal and orthorhombic FeSi2. The leaching behaviour of the various phases, which incorporate the major impurities (Al-Fe-Si, FeSi2, Caalsifer, Ca-Si and CaAl2Si1.5) was studied using a two-step procedure: the first stage with HCl (22%, 6 h, 102-degrees-C) and the second with HCl+FeCl3.6H2O (22%+40%, 12 h, 102-degrees-C). The results show that both Caalsifer and Al-Fe-Si phases are susceptible to leaching, while tetragonal and orthorhombic FeSi2 remain as solid residues.
Idioma:
Inglês
Tipo (Avaliação Docente):
Científica
Nº de páginas:
8