Theoretical and practical possibility to stabilize ¹³⁷Cs(Na)-bearing liquid radioactive waste in mineral-like forms which are geochemically compatible with granithoids in its long-term disposal was demonstrated. Perforated cenospheres (SiO₂/Al₂O₃=3.4) of fly ash generated from combustion of kuznetskii coal was used as an aluminosilicate precursor. It was established that solidification of Cs-bearing solutions at 750-1100 °С via the proposed route resulted in glass-crystalline compounds incorporating 53-79 wt. % pollucite with the Cs leaching rate being by 2-3 order of magnitude lower than the standard parameter accepted in Russia for solidified high level waste.