Abstract
This study presents a comprehensive investigation of producing solid forms of liquid radioactive waste by selective sorption using perlite as a sorbent. The technological process includes impregnation of perlite with a model salt-containing liquid radioactive waste (LRW), drying to remove excess moisture, pressing with sample formation, and subsequent sintering in a muffle furnace. Sintering was carried out in the temperature range of 300–500 ºC with a holding time of 60 minutes. Microstructural analysis using optical microscopy and scanning electron microscopy revealed a transition from a highly porous structure to a denser and more cohesive microstructure with increasing sintering temperature. As the temperature rises to 400 ºC, material densification becomes clearly evident; however, at higher temperatures, a slight decrease in density is observed. The microhardness of the samples increases throughout the investigated temperature range, indicating strengthening of interparticle bonds and correlating with the microstructural analysis results. The obtained findings confirm the significant role of sintering temperature in the formation of structure and mechanical properties of perlite-based solid forms and demonstrate the potential of the proposed approach for immobilization of salt-containing liquid radioactive waste.