Method of extracting lithium compound(s)

The invention relates to a method and apparatus of preparing lithium compound(s) from lithium-containing mineral. The method comprises a) a leaching step, wherein the lithium-containing mineral is leached in aqueous leach solution containing alkaline carbonate, for liberating lithium and phosphate (s) from the lithium-containing mineral, thus obtaining leach slurry containing lithium carbonate and phosphate (s) leach slurry, b) a carbonization step, wherein the leach slurry containing lithium carbonate and phosphate(s), obtained from the leaching step, is reacted with an alkali earth metal compound in the presence of C02 for obtaining a carbonated slurry containing lithium hydrogen carbonate, and for precipitating phosphate (s) contained in the leach slurry as insoluble phosphate compound(s), c) a solid-liquid separation step, wherein the carbonated slurry obtained from carbonization step is subjected to solid-liquid separation wherein the undissolved mineral and phosphate compound(s) are separated as solids that can be recovered or discarded, thereby obtaining a solution containing lithium hydrogen carbonate.