磷酸盐水泥对137Cs的固化性能

以含95％MgO的重烧镁砂、磷酸盐和硼砂为原料，制备了磷酸盐水泥，研究其对137Cs的固化性能。通过XRD衍射分析、SEM电镜扫描等手段对固化体物相组成及显微结构进行分析，参照国家标准“放射性废物固化体长期浸出试验”（GB7023—86）对固化体进行抗浸出性能试验。结果表明，当以磷酸氢二铵为原料时，137Cs的加入会降低磷酸盐水泥固化体的抗压强度，137Cs的含量越多，强度损失越小；当以磷酸二氢铵为原料时，随着137Cs的加入，强度先减小后增大，掺量为1．6％时强度甚至超过了空白体系；以磷酸二氢钾为原料时，137Cs的加入会使强度减小，减小程度和掺量关系的规律性不明显。以磷酸二氢铵、磷酸二氢钾为原料的固化体抗压强度明显优于以磷酸氢二铵为原料的固化体。以磷酸二氢铵为原料的固化体，137Cs的42d浸出率和累计浸出分数低至2．1×10-4（em·d11）和7．74×10^-3cm，强度值和浸出率均优于国家标准相关要求，表明了磷酸盐水泥对137Cs有良好的固化效果。

Testing and Researching on Phosphate Cement Performance in Solidifying Radionuclide 137Cs

Using the dead burned magnesia and phosphate（ containing 95 % MgO ）as raw materials, the phosphate cement doped with 137 Cs has been synthesized. The phase composition, microstrueture have been investigated by XRD and SEM, anti-leaching performance test has also been done with GB 7023 - 86, radioactive waste solidified body long-term leaching experiment. Experimental results show that ad- dition of 137 Cs reduces the compressive strength of phosphate cement solidified, and the more addition will led to the lower loss when diammonium phosphate as a raw material; When ammonium dihydrogen phosphate as raw material, with the addition of 137Cs, the strength decreases and then increases, when the dosage is 1.6%, even more than the blank system; When the potassium dihydrogen phosphate as raw material, the strength will decrease, the regularity of the relationship between the reducing and content is not obvious. The compressive strength of solidified of samples with ammonium dihydrogen phosphate or potassium dihydrogen phosphate as raw material, is obviously superior to those of samples with diam- monium hydrogen phosphate as raw materials. With ammonium dihydrogen phosphate as raw material, the leaching rate and accumulated leaching scores are only 2.1 × 10 ^-4 cm/d and 7.74 ×10^ -3 cm in 42 d. The compressive strength and the leaching rate have been better than the GB, so Phosphate cement has good solidifying effect.