低放高盐模拟核废液水泥固化体中无机盐的赋存状态研究

采用水泥固化法对模拟核废液（主要核素为137^Cs,90^Sr,主要含钠盐（质量分数〉15%））进行固化并在普通硅酸盐水泥中掺入矿渣、粉煤灰、沸石及凹凸棒土掺合料,以观察掺合料对固化体中无机盐赋存状态的影响。采用SEM,XRD及FT-IR对核废物固化基材的微观结构、物相及产物组成进行了表征与分析。结果表明：引入矿物掺合料能降低水泥固化体中无机盐的流失量,尤其掺入矿粉使无机盐的流失量降至82.5%;废液中大部分无机盐以沉淀或持留在水泥水化产物中的形式存在于硬化水泥石的孔隙中;矿物掺合料引入大量SiO2,使得水泥石中Ca（OH）2相基本消失,C-S-H凝胶的含量大幅度提高,部分Na^＋进入C-S-H凝胶的层间位置从而提高盐的固容量。

The Effect of Inorganic Salt for Hydration Products of Cement Solidified Forms and the Existence State

The low and intermediate level radioactive liquid waste is a high slat and alkali-loaded waste,its main nuclide are137 Cs and90Sr,including sodium salt（ 15 %）. Through mixed with slag,fly ash,zeolite and Palygorskite to modify ordinary Portland cement. The microstructure,phase and composition of hydration products of solidification materials for nuclear wastes were investigated by SEM,XRD and FT-IR. The existence state of inorganic salt in cement solidified forms and the influence of inorganic salt to hydration products of cement matrix material solidified forms were discussed. The results show that the addition of mineral admixture reduces the loss of inorganic salt,especially the addition of slag and fly-ash solidified forms reduces the loss to 82. 5%; Most inorganic salt of waste liquid as the form of precipitation or the cement hydration products exists in the pore of cement matrix material solidified forms; owing to the mineral admixture bringing in much SiO2,Ca（OH）2phase disappeared absolutely and C-S-H gels content increased significantly; a part of Na＋gone into C-S-H gels＇ layers to improve the salt content.