NOVELTY - Preparing lithium carbonate, comprises: reacting an aqueous composition comprising lithium hydroxide with carbon dioxide by sparging carbon dioxide into the composition, at a pH of 10-12.5, to obtain a precipitate comprising lithium carbonate; inserting at least a portion of the precipitate into a clarifier and obtaining a supernatant comprising lithium bicarbonate and a solid comprising lithium carbonate; separating the solid; and heating the supernatant at a temperature of at least 85 degrees C so as to at least partially convert lithium bicarbonate into lithium carbonate.    USE - The processes are useful for preparing lithium carbonate (claimed), which is used: as an additive in aluminum molten salt electrolysis and in enamels and glasses; to control manic depression; in the production of electronic grade crystals of lithium niobate, tantalate and fluoride; and in the emerging technology of lithium batteries. No biological data given.    ADVANTAGE - The process provides lithium carbonate with high purity.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are also included for:    (1) a process (P1) of preparing lithium carbonate, comprising submitting an aqueous composition comprising a lithium compound to an electrodialysis or electrolysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide, where during the electrodialysis or electrolysis, the aqueous composition is at least substantially maintained at a pH of 9.5-12.5, and converting the lithium hydroxide into lithium carbonate;    (2) a process (P2) for preparing lithium carbonate, comprising leaching an acid roasted lithium-containing material with water so as to obtain an aqueous composition comprising lithium and at least one metal ion, reacting the aqueous composition comprising lithium and metal ion with a base so as to obtain a pH of 4.5-6.5 and thus at least partially precipitating the metal ion under the form of at least one hydroxide so as to obtain a precipitate comprising the hydroxide and an aqueous composition comprising lithium and having a reduced content of the metal ion, and separating the aqueous composition from the precipitate, and optionally reacting the aqueous composition comprising lithium and having reduced content of metal ion with another base so as to obtain a pH of 9.5-11 .5, and with optionally at least one metal carbonate, thus at least partially precipitating at least one metal ion optionally under the form of at least one carbonate so as to obtain a precipitate optionally comprising the carbonate and an aqueous composition comprising lithium and having a reduced content of the metal ion, and separating the aqueous composition from the precipitate, contacting the aqueous composition comprising lithium and having a reduced content of the metal ion with an ion exchange resin so as to at least partially remove at least one metal ion from the composition, thus obtaining an aqueous composition comprising a lithium compound, submitting the aqueous composition comprising lithium compound to an electrodialysis or an electrolysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide and converting the lithium hydroxide into lithium carbonate; and    (3) a process (P3) of preparing lithium carbonate, comprising leaching a base-baked lithium-containing material with water so as to obtain an aqueous composition comprising lithium and at least one metal ion, reacting the aqueous composition comprising lithium and metal ion with the base to obtain a precipitate comprising hydroxide and an aqueous composition comprising lithium and having a reduced content of metal ion, and separating the aqueous composition from the precipitate, optionally reacting the aqueous composition comprising lithium and having the reduced content of metal ion with another base so as to obtain a pH of 9.5-11.5, and with optionally at least one metal carbonate, thus at least partially precipitating at least one metal ion optionally under the form of at least one carbonate so as to obtain a precipitate optionally comprising the carbonate and an aqueous composition comprising lithium and having a reduced content of the metal ion, and separating the aqueous composition from the precipitate, contacting the aqueous composition comprising lithium and having a reduced content of metal ion with an ion exchange resin so as to at least partially remove at least one metal ion from the composition, thus obtaining an aqueous composition comprising a lithium compound, submitting the aqueous composition comprising the lithium compound to an electrodialysis or electrolysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide and converting the lithium hydroxide into lithium carbonate, or leaching the base-baked lithium-containing material with water, optionally reacting the aqueous composition comprising with the base, at least partially precipitating the metal ion under the form of at least one hydroxide so as to obtain a precipitate comprising hydroxide and an aqueous composition comprising lithium and having a reduced content of the metal ion, and separating the aqueous composition, optionally reacting the aqueous composition comprising with another base so as to obtain a pH of 9.5-11.5, and with optionally at least one metal carbonate, thus at least partially precipitating metal ion optionally under the form of at least one carbonate so as to obtain a precipitate optionally comprising the carbonate and an aqueous composition comprising lithium and having a reduced content of metal ion, and separating the aqueous composition, contacting the aqueous composition with an ion exchange resin so as to at least partially remove at least one metal ion from the composition, thus obtaining an aqueous composition comprising a lithium compound, submitting the aqueous composition comprising the lithium compound to an electrodialysis or electrolysis under conditions suitable for converting at least a portion of the lithium compound into lithium hydroxide and converting the lithium hydroxide into lithium carbonate.