Method for obtaining inorganic sorbent for extraction of lithium from lithium-containing brines

A method for obtaining an inorganic sorbent for extraction of lithium from a lithium-containing brine, the method comprising:

• contacting a mixture of at least one soluble manganese (II) salt in an aqueous solution and at least one aluminum (III) salt in an aqueous solution with an alkali solution in a reaction container in a mother solution in the presence of an alkali metal permanganate to obtain a precipitate of a mixed hydrated manganese (III), manganese (IV), and aluminum (oxide, which comprises a non-stoichiometric compound;
• washing the obtained precipitate by decanting with deionized water to a certain content in the mother solution of the at least one alkali metal salt;
• discontinuing the decanting and settling the precipitate in the reaction container to a predetermined level;
• removing a transparent part of the mother solution to obtain a precipitate suspension in a residue of the mother solution;
• transferring the obtained precipitate of the precipitate suspension in the residue of the mother solution to a freezer container and freezing the precipitate to a solid frozen state for obtaining a mixed hydrated manganese (III), manganese (IV), and aluminum (III) oxide in an icy granular form having a surface;
• removing at least one alkali metal salt from the surface of the icy granular form;
• thawing the mixed hydrated manganese (III), manganese (IV), and aluminum (III) oxide to form a resulting granulated mixed hydrated manganese (III), manganese (IV), and aluminum (III) oxide and thawing the mother solution to form a thawed mother solution;
• separating the icy granular form from an excess of the thawed mother solution;
• converting the resulting granulated mixed hydrated manganese manganese (IV), and aluminum (III) oxide into an H-form of the granulated mixed hydrated manganese (III), manganese (IV), and aluminum (III) oxide by treating thereof with a solution of an acid;
• converting the H-form of the granulated mixed hydrated manganese (III), manganese (IV), and aluminum (III) oxide into a Li-form of the granulated mixed hydrated manganese (III), manganese (IV), and aluminum (III) oxide by treating thereof with a solution of a lithium-containing compound;
• drying and calcining the Li-form of the granulated mixed hydrated manganese (III), manganese (IV), and aluminum (III) oxide to obtain a dehydrated granulated mixed manganese (III), manganese (IV), and aluminum (III) oxide, which contains in its composition four oxides and comprises a lithium-form of an inorganic ion-exchanger;
• and
• converting the obtained lithium-form of an inorganic ion exchanger into an H-form of the ion-exchanger by treating thereof with an acid solution.