Method for the production of lithium carbonate

A process (1) for the production of lithium carbonate from an aqueous salt solution (2) at least containing lithium ions, strontium ions, chloride ions and calcium ions,

• characterized in that
• (1) the aqueous salt solution (2) with a lithium content of at least 0.005% by weight and a maximum of 0.2% by weight is condensed in a first evaporation step (3) at a temperature between 40° C. and 160° C. until a concentrate I with a water content of ≤70% by weight and >60% by weight is formed,
• (2) in a second evaporation step (4), the concentrate I is condensed at a temperature between 60° C. and 180°° C. until a concentrate II with a water content of ≤60% by weight is formed,
• (3) after the second evaporation step (4), the concentrate II is cooled down to a temperature of T≤40° C. in a cooling step, and a solid residue II-2 is formed in the cooling step and separated from the concentrate II, wherein the solid residue II-2 contains strontium chloride and/or strontium chloride hydrate,
• (4) in a Li concentration step (5), the lithium content is raised to at least 0.14% by heating the concentrate II to a temperature of at least 60° C. and thus a lithium-rich concentrate III and a residue III are formed, wherein the residue III contains calcium chloride and/or calcium chloride hydrate, and the residue III is separated out,
• (5) in a precipitation step (6), solid lithium carbonate is formed from the concentrate III by adding carbonates, hydrogen carbonates, carbon dioxide and/or carbon dioxide in combination with a base, and
• (6) the lithium carbonate which is precipitated out or crystallized from the concentrate III by means of carbonate is separated out, whereupon a mother liquor (8) remains.