Link for citation: Dolmatov O.Yu., Kuznetsov M.S., Semenov A.O. Development of matrix material based on aluminate perovskite for immobilization of actinides by self-propagating high-temperature synthesis. Bulletin of the Tomsk Polytechnic University. Geo Assets Engineering, 2021, vol. 332, no. 10, рр. 160–170. In Rus.

The relevance of the research is determined by the need to developing the method for obtaining mineral-like matrix materials intended for immobilization of the most hazardous radioactive waste of the nuclear industry. The use of the self-propagating high-temperature synthesis technology to obtain such materials is more resource-saving and does not require complex technological equipment and operations compared to traditional ways of production. The main aim of the research is to define and propose a method for producing neodymium aluminate as a matrix material for the actinide fraction of radioactive waste. Objects of the research are neodymium aluminate NdAlO₃ with the structure of the mineral perovskite, which is used as an imitator of the trivalent fraction of radioactive waste. Methods: evaluation and analysis of the matrix material creation by computer modeling of the self-propagating high-temperature synthesis; laboratory experiments on the synthesis of neodymium aluminate; determination of the morphological composition of the material by XDR phase analysis Results. The paper describes a theoretical and simulation model for determining the fundamental possibility of the self-propagating high-temperature synthesis of a matrix material based on neodymium aluminate, intended for immobilization of high-level radioactive waste. Numerical simulation methods allowed us to consider various synthesis reactions of such material and determine the maximum possible amount of inclusion of a trivalent actinide simulator. Thus, it is necessary to use the reaction of SH-synthesis of aluminum-nickel with an additional content of no more than 46 wt. % of Nd₂O₃-Al₂O₃ (oxide component ratio of 3,3:1) system in the initial mixture to obtain NdAlO₃. The experimental study was carried out on the synthesis of the matrix material based on the results of the developed model. The authors have determined the optimal conditions for preparation of the components batch: the initial system density should not exceed 5,29 g/cm³ which corresponds to pressure of 40 MPa; the maximum possible inclusion of Nd₂O₃-Al₂O₃ into Ni-Al system is not more than 40 wt. %. The performed XRD analysis showed the presence of a neodymium aluminate phase in all synthesized samples; the maximum proportion of NdAlO₃ is achieved during the synthesis of a sample with 40 wt. % of Nd₂O₃-Al₂O₃ additive and pressure of 30 MPa. Thus, the use of a resource-efficient and simple technology of self-propagating high-temperature synthesis makes it possible to obtain a reliable matrix material for radioactive waste immobilization.