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Studies on Countercurrent Electromigration of Molten Salts with an aim of High Enrichment of <^6Li>

高富集<^6Li>熔盐逆流电迁移研究

基本信息

批准号：
60470160
负责人：
OKADA Isao
金额：
$ 2.37万
依托单位：
Tokyo Institute of Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1985
资助国家：
日本
起止时间：
1985 至 1986
项目状态：
已结题

项目摘要

Although enriched <^6Li> is useful, no method has been established in Japan even on a laboratory scale. Countercurrent electromigration of molten salts is promissing for enrichment particularly of isotopes of alkali metals and hence of <^6Li> . However, enrichment of <^6Li> , which is to be held at the cathode, is not so easy as that of <^7Li> because of inevitable low current density there. To avoid this, the method of <^6Li> enrichment around the boundary between molten <LiNO_3> and molten <NH_4> <NO_3> at the cathode was previously devised by us. In this study, electromigration cells of "horizontal type" was made; the separation tube was placed nearly horizontally in which the boundary was established near the relatively large cathode compartment containing molten <NH_4> <NO_3> . The part of the separation tube was heated at about 300 ゜C, while the part of the cathode compartment was heated at about 180 ゜C. Lithium-6 was enriched from 7.4% to 82% in 31 days without corrosion trouble. The enrichment took place around the rather sharp boundary between <LiNO_3> and <NH_4> <NO_3> . The elementry separation factor, that is, the relative difference in internal mobilities of <^6Li> and <^7Li> in neat <LiNO_3> , <LiNO_3> - <NH_4> <NO_3> mixture and <LiNO_3> - <KNO_3> mixture melts, was measured.The effect of mixing on the separation factor is not clear. The separation factor increases with rising temperature. This can be interpreted microscopically with molecular dynamics simulation. The following methods are to be found in the future:(1) detecting the boundary between <LiNO_3> and <NH_4> <NO_3> from the outside and (2) the extracting very small amount of enriched <^6Li> from molten <NH_4> <NO_3> at the cathode. If these are solved, <^6Li> could be enriched more effectively.

尽管浓缩锂是有用的，但在日本还没有建立起一种即使是实验室规模的方法。熔盐的逆流电迁移有利于碱金属同位素的富集，从而有利于~6Li和~6Li；的富集。然而，将在阴极进行的浓缩并不像浓缩那样容易，因为那里的电流密度不可避免地很低。为了避免这种情况，我们先前设计了在阴极的熔体和熔体之间的界面附近富集锂和硝酸锂的方法。在本研究中，制作了“卧式”电迁移池，分离管被放置在接近水平的位置，其中边界被建立在较大的含有熔体的阴极室附近。分离管部分加热温度约为300゜C，阴极室部分加热温度约为180゜C，锂-6在31天内从7.4%浓缩到82%，没有腐蚀问题。在&lt；LiNo_3&gt；和&lt；NH_4&gt；&lt；NO_3&gt；之间有明显的分界线。测定了LINT；LINO_3&GT；，LINO_3；LINO_3&GT；-LT；NH_4&GT；&LT；NO_3&GT；混合物和&LT；LiNO_3&GT；-&LT；KNO_3&GT；混合熔体的元素分离因子，即&lt；LiNO_3&gt；-&lt；KNO_3&gt；混合对分离因子的影响不明显。分离系数随温度升高而增大。这可以用分子动力学模拟从微观上解释。未来将探索以下方法：(1)从外部探测~lt；LiNO_3&gt；和&lt；NH_4&gt；&lt；NO_3&gt；；(2)从阴极熔体中提取极少量的浓缩物。如果这些问题得到解决，就可以更有效地进行浓缩。