Oceanic research and possible evaluation of lithium recovery from deep ocean waters near Palau and Fiji islands

Abstract

We investigated ion components (Li⁺, Na⁺, K⁺, Mg²⁺, Ca²⁺, Cl^-, Br^-, SO₄^2-), and their vertical distributions through seawater close to Palau and Fiji islands, for the possible evaluation of recovery of valuable ion components, especially lithium ion. At all sites of both seas, Li⁺ concentrations were 0.15-0.16 mg/L, and kept constant through out the vertical depth, and main ion components in both seawaters also agreed with each other. The ion compositions of seawaters adjacent to Palau and Fiji were almost the same as those in Imari Bay in Japan. λ-MnO₂ adsorbent, which has been used for our benchmark plant experiment for Li⁺ recovery from seawater, could effectively adsorb Li⁺ from deep seawater with low temperature compared with surface seawater with high temperature. These results demonstrate that Li⁺ can be effectively recovered from the deep ocean water near Palau and Fiji islands using the adsorption technique with λ-MnO₂ adsorbent.