Leaching Behavior of Sr²⁺, Cs⁺ in Synthesized Zeolite From Fly Ash-Solidified Waste Forms

Synthetic zeolite was prepared by hydrothermal method using fly ash from power plant as raw material. Cs⁺ and Sr²⁺ were isolated and enriched by synthetic zeolite from the radioactive waste liquid. Then, geopolymer was made with fly ash and synthetic zeolite, using sodium silicate as activator. Finally, the physical properties and the leaching resistance of the solidified body were tested, and the leaching mechanism was preliminarily discussed by XRD and SEM technology. The results show that the compressive strength and the leaching resistance of the solidified body is significantly affected by the zeolite dosage. When the dosage is 20%-30%（mass fraction）, the compressive properties reach the national standard, and the leaching rate and the accumulated leaching fraction are far lower than the national standard limits. According to the data, the curing effect of Sr²⁺ and Cs⁺ in the solidified body is different, and the curing effect of Sr²⁺ is more excellent. The leaching rate of 42 d is 1.87×10^-6 cm/d, and the leaching fraction is 3.3×10^-4cm. The experimental reveal that the Sr²⁺ and Cs⁺ of synthesized zeolite from fly ash have excellent curing effect.