Synthesis and study of the chemical stability and strength of zirconium phosphates with the structure of langbeinite with imitators of high-level radioactive waste (HLRW)

Resumo

Crystalline zirconium phosphates with the langbeinite structure containing macroquantities of elements that imitate high-level radioactive waste (HLRW) (Cs 4.6 wt %, Sr 6.2 wt %, La 10.0 wt %, or U⁴⁺ 11.6 wt %) have been synthesized. To impart finely the dispersed materials with the necessary rheological properties, they have been made more compact with the addition of an 2.4–4.4 wt % aluminophosphate binder. The rate of leaching (logR) of the prepared langbeinite samples in distilled water at room temperature for 100 days decreased to–6.1 (Cs),–5.4 (Sr),–5.5 (La), and–5.6 (U) g/(cm² day) with a noticeable trend toward further reduction, which meets, in practical terms, the requirements for the matrix material used for HLRW management. The samples’ axial compression strengths after leaching tests varied from 600 to 1100 kg/cm².