Provided is a method for producing a lithium-containing solution that allows increasing a content rate of lithium in a solution after an eluting step, and suppressing an amount of an eluted solution used in a process after the eluting step, thus suppressing production cost of lithium.
A method for producing a lithium-containing solution includes an adsorption step of bringing a lithium adsorbent obtained from lithium manganese oxide in contact with a low lithium-containing solution to obtain post-adsorption lithium manganese oxide, an eluting step of bringing the post-adsorption lithium manganese oxide in contact with an acid-containing solution to obtain an eluted solution, and a manganese oxidation step of oxidating manganese to obtain a lithium-containing solution with a suppressed manganese concentration. The adsorption step, the eluting step, and the manganese oxidation step are performed in this order, and the acid-containing solution includes the eluted solution with acid added. The method allows the usage amount of the acid in the eluting step to be suppressed, the content rate of lithium in the eluted solution after the eluting step to be increased, and thus the production cost of the lithium-containing solution to be suppressed.