Interaction of Nitric Acid and Zn Intermetallides of Fe, Cr, Ni Obtained after Stripping Zn from EP823 Steel Solutions in Zinc

Two samples of the steel EP823 solution in zinc were prepared. The samples were undergone to zinc vacuum distillation. X-ray analysis showed that the residue particles have a different structure and ratio of elements, depending on zinc residual content. Needle-type particles consist mainly of iron (over 60 wt%) and 9-12% of zinc. Sponge-type particles consist mainly of zinc (over 70%). Chromium localize in zinc-rich particles.In the nitric acid treatment (4 and 8 mole/l) and 6 hours boiling, from 60 wt% to 70 wt% of the sample passed into solution. X-ray spectrum analysis shows that the main phase of the insoluble residue is a solid solution of (Cr,Zn,Fe)O4.