Research of lithium-6 isotope enrichment technology by electrodialysis under special voltage profile

2022 Fiscal Year Final Research Report

• Project/Area Number: 19H02639
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Single-year Grants
• Section: 一般
• Review Section: Basic Section 31010:Nuclear engineering-related
• Research Institution: Hirosaki University
• Principal Investigator: Sasaki Kazuya 弘前大学, 理工学研究科, 教授 (70631810)
• Co-Investigator(Kenkyū-buntansha): 向井 啓祐 京都大学, エネルギー理工学研究所, 助教 (70807700)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: リチウム / 同位体濃縮 / 電気透析 / 核融合

Outline of Final Research Achievements

In the lithium isotope enrichment by electrodialysis applying a special voltage profile that achieved high isotope enrichment in our past research, we studied to clarify the mechanism of obtaining a large isotope enrichment.
It was found that isotope enrichment occurs in two processes, surface adsorption-dissociation and ion migration in the electrolyte, and the contribution rate of the latter increases at lower temperatures. We investigated the temperature dependence of the migration rate of 6Li and 7Li and clarified that there is a difference in the activation energy of migration. From this result, it was found that the lower the temperature, the higher the isotope enrichment rate. Furthermore, as a result of investigating the time course of the isotope enrichment rate by making a prototype scale device, it was confirmed that the isotope ratio gradually decreased toward the natural isotope ratio with the passage of time.

Free Research Field

核融合

Academic Significance and Societal Importance of the Research Achievements

質量数6のリチウム同位体（6Li）を90%以上に濃縮するための技術を開発するための有望な技術の一つであるリチウムイオン伝導性固体電解質を隔膜とする電気透析技術を高度化し、あるいはカスケード化することで実用化するために必要な、基礎的知見を獲得した。本技術は、21世紀中ごろに実用化が望まれている核融合炉発電における最大の課題の一つである6Li同位体濃縮率を高めたリチウムを提供するといった社会的意義がある。また、電気透析時の同位体による挙動の違いを解明するという点で学術的意義がある。