Synthesis of rare earth phosphates in molten LiCl–KCl eutectic: Application to preliminary treatment of chlorinated waste streams containing fission products
Synthesis of rare earth phosphates in molten LiCl–KCl eutectic: Application to preliminary treatment of chlorinated waste streams containing fission products
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DOI：
10.1016/j.jnucmat.2008.09.005
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发表时间：
2008-11
影响因子：
3.1
通讯作者：
D. Hudry;I. Bardez;A. Rakhmatullin;A. Rakhmatullin;C. Bessada;C. Bessada;F. Bart;S. Jobic;P. Deniard
中科院分区：
文献类型：
--
作者：
D. Hudry;I. Bardez;A. Rakhmatullin;A. Rakhmatullin;C. Bessada;C. Bessada;F. Bart;S. Jobic;P. Deniard
本文研究了在500°C的空气中，在LiCl-KCl共晶熔体中，稀土磷酸盐（RE=La，Ce，Pr，Nd和Lu）从RECl 3中的沉淀。使用磷酸二氢铵（NH 4 H2 PO 4）作为磷前体。X-射线衍射分析表明形成了具有独居石（La，Ce，Pr，Nd）或磷钇矿（Lu）结构的化合物。31 P NMR光谱测量证实镧形成了纯独居石，这表明LaCl 3 → LaPO 4的转换因子接近100%。这些结果表明，NH 4 H2 PO 4的化学计量添加足以在熔融LiCl-KCl中在500°C下获得无水稀土磷酸盐的定量沉淀。这种前体的优点是在回收稀土磷酸盐后不会改变介质的化学成分，可在通过高温化学工艺对含有乏燃料后处理产生的裂变产物的氯化浴进行净化的第一步中考虑使用这种前体。
The precipitation of rare earth phosphates (RE=La, Ce, Pr, Nd, and Lu), from RECl3was investigated in molten LiCl–KCl eutectic at 500°C in air. Ammonium dihydrogenphosphate (NH4H2PO4) was used as the phosphorus precursor. X-ray diffraction analysis indicated the formation of compounds with monazite (La, Ce, Pr, and Nd) or xenotime (Lu) structures.31P NMR spectroscopy measurements confirmed that lanthanum formed pure monazite, which indicates a LaCl3→LaPO4conversion factor near 100%. These results demonstrate that the stoichiometric addition of NH4H2PO4is sufficient to obtain quantitative precipitation at 500°C of anhydrous rare earth phosphates in molten LiCl–KCl. The use of this type of precursor, which has the advantage of not modifying the chemical composition of the medium after recovery of the rare earth phosphates, could be considered during the first step of purification of chlorinated baths containing fission products arising from spent fuel reprocessing by a pyrochemical process.