Abstract

Ceramic matrix composites for solidification and disposal of actinide-rare-earth fraction of high-level waste (HLW) were prepared by sintering of nanosized powders of 0.8LaPO₄–0.2Al₂O₃, 0.8LaPO₄–0.2Y₂O₃ and 0.8LaPO₄–0.2ZrO₂ obtained from 0.8LaPO₄ · nH₂O–0.2Al(OH)₃, 0.8LaPO₄ · nH₂O–0.2Y(OH)₃ and 0.8L-aPO₄ · nH₂O–0.2ZrO(OH)₂ precursors. These powders-precursors were synthesized via sol-gel technique. After heat treatment at 850°C powders of 0.8LaPO₄–0.2Al₂O₃, 0.8LaPO₄–0.2Y₂O₃ and 0.8LaPO₄–0.2ZrO₂ were obtained. Further powdered compositions were stepwise sintered to prepare ceramic composites which were supposed to be used as matrices for storage of HLW. Rate of La³⁺, Al³⁺, Y³⁺ and Zr⁴⁺ leaching from ceramic matrix composites in strength aqueous solutions of NaCl and Na₂SO₄ simulating underground brine typical for proposed location of HLW geological repository was estimated.

中文翻译：

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基于正磷酸盐镧的陶瓷基复合材料处理高放废物

摘要

通过0.8LaPO的纳米粉末的烧结制备用于凝固和处置的高放废物锕系的稀土类馏分（HLW）陶瓷基复合材料₄ -0.2Al ₂ ö ₃，0.8LaPO ₄ -0.2Y ₂ ö ₃和0.8LaPO ₄ -0.2ZrO ₂从0.8LaPO得到₄ · ñ ħ ₂ -O-0.2Al（OH）₃，0.8LaPO ₄ · ñ ħ ₂ -O-0.2Y（OH）₃和0.8LaPO ₄ · ñ ħ ₂ O–0.2ZrO（OH）₂前体。这些粉末前体是通过溶胶-凝胶技术合成的。在0.8LaPO 850℃的粉末热处理后₄ -0.2Al ₂ ö ₃，0.8LaPO ₄ -0.2Y ₂ ö ₃和0.8LaPO ₄ -0.2ZrO ₂获得。将另外的粉末状组合物逐步烧结以制备陶瓷复合物，该陶瓷复合物应被用作用于存储HLW的基质。NaCl和Na ₂ SO _4的水溶液中陶瓷基复合材料中La ³⁺，Al ³⁺，Y ³⁺和Zr ^4+的浸出率。 估算了拟用于高放废物地质库位置的典型地下盐水模拟。