METHOD FOR PREPARING LITHIUM CARBONATE FROM LITHIUM-CONTAINING NATURAL BRINES Russian patent published in 2018 - IPC C01D15/08 

FIELD: metallurgy.

SUBSTANCE: invention relates to hydrometallurgy of lithium and can be used in the processing of lithium-containing natural waters and process solutions. Lithium aluminum concentrate is prepared by processing a lithium-containing brine with a suspension of freshly precipitated aluminum hydroxide at pH 8.5±0.5, a temperature of 20–50 °C and a stirring time of 20–60 minutes. Resulted concentrate is separated from a mother liquor by filtering on a nutsch filter and fresh water washing at S:L=1:5. Washed cake of the concentrate without drying with a humidity of 60–70 % is loaded into a Soxhlet extractor and treated 10 times with distilled water at a temperature of 100 °C to obtain a concentrated solution of lithium chloride, which for purifying from calcium impurities is heated to 90 °C and, with stirring, is treated with a saturated solution of Na₂CO₃. Lithium carbonate with a 99.6 % basic substance content is obtained from the concentrate ,purified from calcium impurities, by dosing a saturated solution of sodium carbonate into it. Precipitate is separated from the mother liquor, washed step by step with three portions of a saturated solution of Li₂CO₃ at S: L=1:5, after which Li₂CO₃ is dried.

EFFECT: it ensures preparing high-purity lithium carbonate, simplifying and increasing the efficiency of the technological process for the production of lithium carbonate.

1 cl, 1 dwg, 2 tbl, 7 ex