LiCl-KCl 공융염 내 희토류 및 악티나이드 핵종의 인산화반응 거동 연구
Study on the phosphorylation reaction of rare-earth and actinide nuclide in the LiCl-KCl eutectic salt
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In this study, the phosphorylation reaction of rare-earth elements that is nuclideseparation process for the recycling the LiCl-KCl waste salt generated from pyrochemicalprocess has been investigated. The energy profiles of phosphorylation reaction for 4 kindsof rare-earth nuclide (La, Ce, Pr, and Nd), and the reaction pathways according to thephosphorylation agent of K3PO4-Li3PO4 were analyzed by first-principles calculation. It isfound that the phosphorylation of La, Ce, Pr, and Nd rare-earth nuclides proceeds byexothermic reaction under the phosphorylation agent of K3PO4-Li3PO4, and rare-earthphosphates lead to form energetically stable crystals (or precipitates) due to the highenergy barrier of reverse reaction. Also, ion energy calculation revealed that K3PO4 iseasily ionized and converted to rare-earth phosphate relative to Li3PO4 as well as K3PO4acts as phosphorylation agent to Li+ ion thus leading to formation of Li3PO4. This explainsthe experimental result why only Li3PO4 precipitates exist after phosphorylation reactionunder excess amount of K3PO4-Li3PO4 agent. Furthermore, through the energy profilecalculation of actinide nuclide, it is estimated that the trace of actinide nuclide in theLiCl-KCl waste salt could be also separated from the waste salt by the phosphorylationreaction promoted by K3PO4-Li3PO4 agent. Consequently, it is considered that the energyprofile study on the phosphorylation reaction could be also applicable to the estimation ofphosphorylation reaction pathways between other types of phosphorylation agent andrare-earth or trace of actinide nuclide for design of the efficient nuclide separationprocess.
Abstract
In this study, the phosphorylation reaction of rare-earth elements that is nuclideseparation process for the recycling the LiCl-KCl waste salt generated from pyrochemicalprocess has been investigated. The energy profiles of phosphorylation reaction for 4 kindsof rare-earth nuclide (La, Ce, Pr, and Nd), and the reaction pathways according to thephosphorylation agent of K3PO4-Li3PO4 were analyzed by first-principles calculation. It isfound that the phosphorylation of La, Ce, Pr, and Nd rare-earth nuclides proceeds byexothermic reaction under the phosphorylation agent of K3PO4-Li3PO4, and rare-earthphosphates lead to form energetically stable crystals (or precipitates) due to the highenergy barrier of reverse reaction. Also, ion energy calculation revealed that K3PO4 iseasily ionized and converted to rare-earth phosphate relative to Li3PO4 as well as K3PO4acts as phosphorylation agent to Li+ ion thus leading to formation of Li3PO4. This explainsthe experimental result why only Li3PO4 precipitates exist after phosphorylation reactionunder excess amount of K3PO4-Li3PO4 agent. Furthermore, through the energy profilecalculation of actinide nuclide, it is estimated that the trace of actinide nuclide in theLiCl-KCl waste salt could be also separated from the waste salt by the phosphorylationreaction promoted by K3PO4-Li3PO4 agent. Consequently, it is considered that the energyprofile study on the phosphorylation reaction could be also applicable to the estimation ofphosphorylation reaction pathways between other types of phosphorylation agent andrare-earth or trace of actinide nuclide for design of the efficient nuclide separationprocess.
참고문헌 (12)
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