New Method Established for Recovering Li From Seawater

Feb 19, 2014
Motohiko Hamada, Nikkei Automotive Technology

Japan Atomic Energy Agency (JAEA) developed a technology of separating lithium (Li) from seawater by using an ionic conductor as a separating film.

This time, JAEA succeeded in refining lithium carbonate (Li2CO3) powder, which is a material for Li-ion rechargeable batteries, by using seawater. Though JAEA has an aim to stably supply Li for nuclear fusion reactors, it is also considering using Li for Li-ion rechargeable batteries.

The new technology provides recovery solution (dilute hydrochloric acid) to both sides of the ion separation film to cause the difference in Li density between seawater and the recovery solution so that Li in the seawater moves to the solution. The move of Li ions to the ionic conductor causes electron flow between the electrodes, generating electricity.

The ionic conductor is a ceramic material having the NASICON crystal structure containing Li, aluminum (Al), titanium (Ti), germanium (Ge), silicon (Si), phosphorus (P) and oxygen (O). In theory, it is a "battery." So, it does not use electricity unlike electrolysis and generates electricity instead. But energy for making materials such as dilute hydrochloric acid and sodium carbonate (Na2CO3) is necessary.

In an experiment of recovering Li from actual seawater, up to about 7% of the Li contained in the seawater was recovered in three days.