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Hydrolysis of Uranyl‐, Nd‐, Ce‐Ions and their Mixtures by Thermal Decomposition of Urea
Author(s) -
Schreinemachers Christian,
Bollen Olivier,
Leinders Gregory,
Tyrpekl Václav,
Modolo Giuseppe,
Verwerft Marc,
Binnemans Koen,
Cardinaels Thomas
Publication year - 2022
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.202100453
Subject(s) - chemistry , uranyl , lanthanide , inorganic chemistry , thermal decomposition , hydrolysis , precipitation , ammonium hydroxide , hydroxide , urea , stoichiometry , decomposition , ternary operation , nuclear chemistry , ion , organic chemistry , physics , meteorology , computer science , programming language
Abstract The hydrolysis of uranyl‐, Nd‐ and Ce‐cations, induced by thermal decomposition of urea was investigated and the impact of the urea content and the experiment temperature on the reaction kinetics was evaluated. Uranyl precipitated as ammonium diuranate (ADU) with varying stoichiometry. Nd(III) and Ce(III) showed comparable pH evolutions and lanthanide carbonate hydroxide ( Ln CO 3 OH) products were identified, whereas Ce(IV) hydrolysed at lower pH and formed CeO 2 . The precipitation behaviour was confirmed for mixtures of uranyl and the lanthanides. Depending on the urea content, a partial co‐precipitation occurred in U/Nd mixtures. The phases formed with Ce(III) and Ce(IV) were also identified in the precipitates of binary U/Ce mixtures. In ternary U/Nd/Ce compositions, a simultaneous precipitation of Nd(III) and Ce(III) was observed and a partial incorporation of the lanthanides into the ADU phase, whereas the precipitation in the presence of Ce(IV)/CeO 2 led to the formation of three individual phases.