Chemistry of lanthanide/actinide oxalates

Speaker

Václav Tyrpekl - Charles University, Czech Republic 

Abstract

Oxalate salts are important materials in the chemical technology of lanthanides and actinides. Thanks to their low solubility they are applied in oxide synthesis and separations. One of the interesting examples is cerium dioxide. Ceria, pure or doped, is an important electrolyte material in solid oxide fuel cells, catalysts, and plutonium surrogates. Even though ceria is a widely studied material, its coprecipitation with the most common doping element, gadolinium, is taken mostly as mastered, which might not be the case. The lecture deals with a comprehensive study of gadolinium-cerium oxalates prepared by coprecipitation of gadolinium (III) and cerium (III) salts by oxalic acid under different reaction conditions and element ratios. For this purpose, we assessed the effects of basic precipitation conditions on the final oxalate size, shape, and conversion into the corresponding oxides. The results showed that coprecipitation with oxalic acid yields an ideal solid solution, which translates into oxides. This low-cost and straightforward synthetic route provides then high-quality solid solutions of Ge-Gd in the oxide lattice. Thus, this approach has a high industrialization potential, with significant advantages over hydrolysis or hydrothermal techniques.

Bioskech

Dr. Václav Tyrpekl is an assistant professor at the Department of inorganic chemistry, Faculty Science, Charles University, Czech Republic since October 2017. He is the leader of the Group of solid-state chemistry and nanomaterials, which is focused on materials synthesis and processing in the energy domain. Namely, the group deals with field-assisted sintering techniques, oxalate chemistry, carbide synthesis, and materials for nuclear safety (e.g. geopolymers). Since 2020 he is a research consultant at UJV Řež a.s., an engineering company in the nuclear industry, Group of severe accident and thermomechanics, Group of generation IV reactors development. He has published about 45+ research articles and is currently supervising 5 Ph.D. and 2 MSc students.  Before joining Charles University, he worked in various European Nuclear Research Institutes in the field of the nuclear fuel cycle, thorium fuel, and high-temperature ceramics. During the years 2016 – 2017 he acted as a project leader in the nuclear fuel cycle at the Belgian Nuclear Research Centre, SCK·CEN, Mol, Belgium, Institute of Nuclear Materials Science, Group of Fuel Materials Analysis. From 2013 to 2016 he was a grant holder at the European Commission, Joint Research Centre, Karlsruhe, Germany, Nuclear Fuel Safety unit. There he met field-assisted sintering techniques and their application in nuclear fuel preparation.
Dr. Tyrpekl holds a PhD from the Université de Strasbourg, while working at CEA Cadarache, France, Department of Nuclear Energy, Division of Nuclear Technology, Laboratory of Severe Accident Mastering. His Ph.D. thesis was focused on the severe accident of light water reactors phenomenology, in particular the interaction of molten core materials with coolant. 

Research focus

High-temperature materials, ceramics, field-assisted sintering, chemistry of lanthanide/actinide oxalates, nuclear fuel cycle