Patent attributes
This invention relates to the separation of lithium from lithium-containing materials, primarily ores such as hectoritic montmorillonite, having about 0.1 to 1.0 percent lithium by weight. The process comprises reducing the particle size of the material to less than about 150 microns; mixing the material with a solid source of sulfates and carbonates at predetermined ratios; granulating the mix with an aqueous solvent in order to obtain granules of 1-10 mm; reacting the granules at temperatures of 950-1100° C.; slurrying the reaction products with an aqueous solution; heating the resulting slurry at about 50° to 100° C. for from about 0.3 to 2 hr; separating the solids and evaporating the solution to separate potassium and sodium salts; separating the liquid portion of the cooled brine, which is treated with sodium carbonate, potassium carbonate with heating to remove interfering alkaline earth metals, cooling and separating the aqueous phase followed by treatment with sufficient alkali carbonate to precipitate the lithium carbonate with filtering of the hot slurry to remove the lithium as solid lithium carbonate.
