Method and electrode for electrochemical recovery of lithium value from aqueous solution

摘要

A novel and efficient electrochemical method is disclosed for the recovery of lithium value from an aqueous solution containing lithium ions in a relatively low concentration together with ions of various kinds of other metallic impurity elements. The method comprises electrochemical selective adsorption of lithium ions from the aqueous solution on to a specific working electrode by applying a DC voltage of a relatively low DC voltage of 0.1-0.4 volt versus a saturated calomel electrode to the working electrode as the cathode opposed to a counterelectrode as the anode and then desorption of the lithium ions therefrom by applying a DC voltage of 0.7-1.2 volts versus a saturated calomel electrode to the lithium-bearing working electrode as the anode opposed to a counterelectrode as the cathode in an aqueous desorption medium containing an electrolyte such as a lithium salt. At least the surface layer of the working electrode is formed from an oxide of manganese prepared by admixing a manganese compound with a limited amount of a lithium or magnesium compound, converting the mixture into oxides by a heat treatment in an oxidizing atmosphere and then removing the lithium or magnesium therefrom by leaching in an acid solution or by an electrochemical means.