Rare earth tungsten bronzes: a new method of synthesis. Perspectives for their application as inert matrices for transmutation of long-life actinide elements

A new method of synthesis of oxide tungsten bronzes containing lanthanide ( Ln) Nd and Eu, based on thermal degradation of polyoxotungstate compounds, is proposed. The simplicity of the method allows to consider this class of compounds with chemical formula, Ln x WO 3, as potential inert target for incineration or transmutation of minor actinides, Am and Cm, in neutron reactors. Nd and Eu were used as analogues of transplutonium elements. Powder X-ray diffraction patterns of compounds synthesized reveal a cubic perovskite structure. The lanthanide content in bronzes was determined by optical spectroscopy analysis. The experimental density of the pressed bronze samples was estimated at 6.58 g cm −3, i.e., 89% of the crystallographic value. The thermal stability of the bronzes synthesized was checked up to 900°C in an inert atmosphere. Leaching tests were performed for europium bronzes in nitric acid solutions using luminescence technique.