磷酸盐水泥对^(90)Sr固化性能的研究

Study of solidification performance of phosphate cement to ^(90)Sr

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90Sr的固化性能.同时,通过XRD、SEM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,90Sr的加入会降低磷酸盐水泥固化体的抗压强度,随着90Sr含量的增大,水泥固化体的强度损失越大,而对于不同原料配方的固化体,90Sr的28d浸出率和累计浸出分数可分别降低至4.57×10-5cm·d-1和7.39×10-3cm,强度值和浸出率均优于国家标准相关要求,表明磷酸盐水泥对90Sr具有良好的固化性能.同时,以磷酸二氢铵、磷酸二氢钾为原料的固化体抗压强度和浸出性能都明显优于以磷酸氢二铵为原料的固化体.

Using dead-burned magnesia（containing 95% MgO） and phosphate as raw materials,the phosphate cement with strontium has been prepared.The phase compositions,microstructure of as-prepared samples have been investigated by XRD and SEM,anti-leaching performance test has also been done with GB 7023—86（Long-term leach testing of solidified radioactive waste forms）.Experimental results show that addition of 90Sr reduces the compressive strength of phosphate cement;with more 90Sr addition,the greater strength loss is found.Phosphate cement has good anti-leaching performance,the leaching rate and accumulated leaching scores are only 4.57×10-5 cm · d-1,7.39×10-3 cm in 28 day.Compared with the samples prepared by different phosphate as raw materials,the compressive strength and leaching properties of samples,with ammonium dihydrogen phosphate or potassium dihydrogen phosphate as raw material,are obviously superior to those of samples with diammonium hydrogen phosphate as raw materials.