Effect of Simulated Radionuclide Strontium on Geopolymerization Process

Safety treatment of the nuclear wastes is an important and challenging task troubled scholars for years. In this work, geopolymer was prepared to solidify simulated radionuclide strontium by 4A zeolite and metakaolinite. The effect of radionuclide strontium with different solidification conditions on electrical conductivity and final setting time were investigated and the variation tendency of electrical conductivity has well been in accord with the “three stage” during the whole geopolymerization process. Meanwhile, the mineral phases and chemical bonds of the geopolymer were analyzed by XRD and FTIR respectively. Results show that: (I)the electrical conductivity during the geopolymerization process has the same variation tendency as the final setting time, (II)strontium caused hysteresis effect on geopolymerization process, (III)strontium takes part in the polymerization reaction according to the XRD of geopolymer, and there's little chemical bond vibration effect with the addition of strontium according to the IR result. The results indicated that zeolite-like minerals are synthesized during the geopolymerization process. The immobilization of simulated radionuclide strontium is mainly attributed to absorption, ion exchange, and physical encapsulation.