Separation and determination of percentile level zirconium in Gd₂Zr₂O₇ by ion chromatography

Gd₂Zr₂O₇ added with ~ 4 -5% Nb is used as a burnable poison in nuclear reactors. Determination of Zr is mandatory for the chemical characterization of Gd₂Zr₂O₇. The determination of Zr in percentile level, in general, is carried out by a gravimetric method. In this method Zr is precipitated as Zr-mandelate by adding mandelic acid. The accuracy of the results is hampered by the presence of Nb, which is prone to precipitate even in acidic media. This necessitates the separation of Nb prior to the gravimetric determination of Zr. Simultaneous separation of Gd and Zr using liquid chromatography would enable their quantification simple and rapid. Previously we reported the feasibility of separating uranium and zirconium simultaneously on a reversed phase column as their 2,6-pyridine dicarboxylic acid (PDCA). Therefore, the feasibility of separating Gd and Zr using polymer based RP column has been explored. PDCA was chosen as eluent because it readily forms complexes with U, Th, Zr etc. in high acidic medium. Based on the results of the previous study wherein U and Zr were separated, the effect of PDCA, KNO₃, HNO₃ and MeOH on the separation of Zr was studied and the final composition of the eluent has been formulated as 0.5 mM PDCA, 0.02 M KNO₃, 0.8 M HNO₃ and 18 % MeOH