Production of lithium carbonate from brines

A process for producing lithium carbonate from natural or industrial brines, which comprises:

• (a) acidifying a brine, which comprises at least lithium, magnesium, boron and water, by mixing an acid therewith so as to maintain a pH of from 0 to 4 and to form boric acid, said pH being measured by diluting the acidified brine with water in a ratio of 1:10;
• (b) removing said boric acid by crystallization and separating boric acid crystals from said brine to produce a boron-depleted brine;
• (c) removing residual boron from said boron-depleted brine by treating said brine with an organic extractant to thereby produce a boron-free brine;
• (d) diluting said boron-free brine with at least a portion of a mother liquor generated in a lithium carbonate precipitation step;
• (e) removing magnesium from said diluted brine by adding sodium carbonate thereto and precipitating and separating magnesium carbonate therefrom to form a magnesium-depleted brine, said removing step (e) results in the removal of 60 to 95%, by weight, of the magnesium contained in said diluted brine;
• (f) removing residual magnesium from said magnesium-depleted brine by adding calcium hydroxide thereto and precipitating and separating magnesium hydroxide therefrom to form a magnesium-free brine;
• (g) adding sodium carbonate to said magnesium-free brine to form and precipitate lithium carbonate;
• (h) separating said lithium carbonate from said brine to thereby obtain a lithium carbonate cake and said mother liquor having a lithium content of 0.1 to 0.3%, by weight.