No CrossRef data available.
Published online by Cambridge University Press: 20 February 2017
Iron and nickel oxidation state and coordination in complex sodiumaluminophosphate based glasses suggested as potential matrices forimmobilization of legacy high level waste currently stored in stainless steeltanks at PA «Mayak» (Ural reg., Russia) were determined byX-ray absorption fine structure spectroscopy (XAFS: XANES/EXAFS). The glassescontaining (wt.%) 20-30 Na2O, 6-12 Al2O3, 40-52P2O5, 2-5 Fe2O3, 1-3 NiO, 0-6B2O3, 10-15 other waste oxides produced by quenchingof their melts were fully amorphous or contained minor Fe and Ni free phases. Fein the glasses was found to be predominantly trivalent with an average Fe-Odistance and a coordination number (CN) in the first shell of 1.94 to 1.97Å and 5.2 to 5.8, respectively, mostly in octahedral oxygenenvironment. Ni is divalent in all the glasses and has in the first shell anaverage Ni-O distance and CN of 1.97 to 2.03 Å and 4.9 to 5.6,respectively. The first shell of both Fe and Ni is somewhat distorted. Thesecond and further coordination shells are weakly appeared exhibiting noclustering and homogeneous distribution of Fe and Ni ions in the glass network.The data on Fe obtained are in good agreement with those from Mössbauerstudy of same glasses. After annealing glasses were partly devitrified andinterpretation of XAFS data is strongly complicated due to Fe and Nipartitioning among crystalline and vitreous phases.