【作者】 姚军； 苏锡光； 龙会遵； 范显华；

【Author】 YAO Jun SU Xi-guang LONG Hui-zun FAN Xian-hua (China Institute of Atomic Energy,Beijing,102413)

【机构】 中国原子能科学研究院；

【摘要】 实验以甘肃红泉膨润土为预选的缓冲、回填材料,研究了核素²³⁷Np在该材料中的吸附行为,在大气和低氧(氧含量低于5×10^-6的Ar气气氛)两种条件下,分别测定了三种膨润土的吸附分配比K)d值,并以混合型膨润土为例研究了pH值和CO₃^2-浓度对Kd值的影响,主要得到如下结果:（1）大气条件下在混合型、Mg-型、Ca-型膨润土上的吸附分配比K_d分别为:47.3 mL/g、52.0 mL/g、42.4 mL/g,低氧条件下分别为:89.3 mL/g、38.8 mL/g、29.0 mL/g。（2）混合型膨润土在pH<9.2时,随着pH的升高,K_d值增大,在pH=9.2时,出现最大值。（3）在大气和低氧两种条件下,在Np的浓度低于NaNpO₂CO₃的溶解度时,随着CO₃^2-浓度增加K_d值减小。更多还原

【Abstract】 The performance of adsorping ²³⁷Np for bentonite as buffer/backfill material was investigated.The adsorption coefficients of ²³⁷Np were determined for three kinds of bentonite under atmosphere and anoxic atmosphere. Further,it was studied that K_d values were affected by pH and CO₃^2-.The results are shown as follows: （1） Distribution coefficients K_d under atmosphere:for mixed-bentonite is 47.3 mL/g,for Mg-bentonite 52.0 mL/g and for Ca-bentonite 42.4 mL/g;and the corresponding K_d under anoxic atmosphere:89.3 mL/g, 38.8 mL/g and 29.0 mL/g,respectively. （2） When pH was lower than 9.2,K_d of the mixed-bentonite increased with the increase of pH and the maximumt K_d value appeared at pH 9.2. （3） K_d of the mixed-bentonite got lower in high carbonate concentration when the total neptunium concentration was smaller than the solubility of NaNpO₂CO₃.更多还原