Studies on the Behavior of Inorganic Ions Caused by Electrodeposition Process. II.
Quantitative Separation of Radioactive Fe, Zn, CrO4 and PO4
1967 Volume 40 Issue 1 Pages 2-9
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1967 Volume 40 Issue 1 Pages 2-9
In order to study the behavior of such ions as Fe3+, Zn2+, Cr042- and PO43- during electrophoretic painting, procedures for their isolation and analytical methods have been examined.
The radioactive ions were added to the mixture of an electrophoretic paint and a solvent (mixture of xylene and n-butanol), extracted from the non-aqueous layer of the mixture, and then separated into individual ion. The reliability of this procedure has been confirmed by the measurements of radioactivity. Extraction of Fe59, Zn65, Cr51 and P32 from the non-aqueous layer.-The ions composed of these radioactive elements were washed out with nitric acid. The yields of Cr51, Zn65 and P32 were at least 95 %. The yield of Fe59 could not be checked due to its weak radioactivity.
Isolation of Cr51 from the nitric acid layer by precipitation of Fe59, Zn65 and part of P32. Cr51 in the nitric acid layer was oxidized with H2O2, then the solution was neutralized in the hope that P32 might be co-precipitated with Fe59 and Zn65 leaving only Cr51 in the solution. The result was not satisfactory because the concentrations of Fe59 and Zn65 were too low to give quantitative precipitations. The amount of Cr51 remained in the liquid layer was as high as 98 %.
Ether extraction of Fe59 from the hydrochloric acid layer. It was confirmed that more than 95 % of Fe59 in the 6 N-HC1 solution of Fe59, Zn65 and P32 could be extracted. The amounts of Zn65 and P32 remained in the solution were 96 and 91 %, respectively.
Isolation of Zn65 with an anion exchange resin. Zn65 present in the 6 N-HCl solution together with P32 was isolated with an anion exchanger (Cl-type) as ZnCl3-ion and recovered by treating the exchanger with distilled water and 0.1 N-HNO3. The amount of Zn65 recovered was close to 100 %. The amount of P32 removed from the solution was only 2 %.
It is clear that the procedures for the precipitation are the key to the reliability of the proposed methods of isolation. It is desirable that the concentrations of Fe59 and Zn65 in the solution are at least 20 p.p.m.
