Separation of lithium isotopes by countercurrent‐exchange‐electrolysis

The separation of the lithium isotopes by countercurrent‐exchange‐electrolysis was investigated. In this process the separation is based on an exchange between a lithium amalgam and a solution of a lithium salt, transported in countercurrent through a column. It appeared possible to obtain a satisfactory countercurrent transport in a packed column. Sand with a particle size between 0.35 and 0.5 mm was found to be a suitable packing material. The reflux at the bottom of a column, where the lithium is transported from the amalgam to the electrolyte solution (anodic reflux) was realized by a continous method based on exchange‐electrolysis. The cathodic reflux is obtained by evaporating the solvent dimethyl formamide, transferring the lithium chloride into water and electrolyzing the lithium chloride solution in water. Experiments carried out during 20 to 40 hours in an exchange‐column with a length of 1 to 2 m resulted in an increase of lithium‐6 content from 7.5 to 13% at the bottom of the column and a decrease of lithium‐6 content from 7.5 to 5.3% at the top of the column.