Conditioning of Spent ion-exchange Resins Followed by Solidification in the Alkali-slag Long-lived Matrix with an Increased Level of Filling with Resins

The possibility for spent ion-exchange resins (IER) of intermediate specific activity to be solidified in alkali-slag (geocement) water-resistant matrixes with an increased level of filling with resins was studied. Comparative tests of the IER immobilization process were done for justifying the most technologically effective matrix material. We used three different alkali-slag cementing systems and the prepared simulated pulps of IER with the specific activity of 3x10(8) Bq/L, saturated with Cs-137 radionuclide. The manufactured samples of the alkali-slag compounds, filled with IER at the level of 24-27% by weight, meet the regulatory requirements set in NP-019-15 code and feature better working quality parameters (mechanical strength: 5-14 MPa, leaching rate of Cs-137, Na, Ca: < 2x10(-4) g/cm(2)'" day on the 7th-10th day, mechanical strength of compounds rises by the factor of 1.2-1.5 after immersion tests). The incorporation of the spent IER in the most technologically effective alkali-slag matrix makes it possible to decrease the cementing material consumption by the factor of 2.4 in comparison with Portland cement and by the factor of 1.3 in comparison with the known slag binders, while a compound with better quality parameters is produced. The research was done with the support of the Russian Ministry of Education and Science (unique identifier of the applied research studies - RFMEFI57915X0101) for justifying a new energy-efficient and resource-saving technology of reprocessing the spent IER-containing waste.