Methods for treating lithium-containing materials

A method for preparing lithium hydroxide and recovering lithium sulfate, said method comprising:

• mixing a lithium-containing material with an acidic aqueous composition comprising sulfuric acid and optionally comprising lithium sulfate and thereby obtaining a mixture;
• roasting said mixture to obtain a roasted, lithium-containing material;
• leaching said roasted material under conditions suitable to obtain a first aqueous composition comprising lithium sulfate;
• submitting said first aqueous composition comprising lithium sulfate to an electromembrane process under suitable conditions for at least partial conversion of said lithium sulfate into lithium hydroxide and to obtain a second aqueous composition comprising lithium sulfate, said electromembrane process involving a hydrogen depolarized anode;
• increasing concentration of acid in said second aqueous composition by removing water from said second aqueous composition by heating said second aqueous composition so as to cause a substantially selective precipitation of lithium sulfate monohydrate and to obtain a third aqueous composition;
• recovering said lithium sulfate monohydrate by separating said lithium sulfate monohydrate from said third aqueous composition;
• and
• using said third aqueous composition comprising lithium sulfate as said acidic aqueous composition for mixing with said lithium-containing material and to obtain said mixture.