A process for preparing lithium carbonate, said process comprising: leaching a sulphuric acid roasted lithium-containing material with water so as to obtain an aqueous composition comprising lithium sulphate and at least one metal ion; reacting said aqueous composition comprising lithium sulphate and said at least one metal ion with a base so as to obtain a pH of about 4.5 to about 6.5 and thereby at least partially precipitating said at least one metal ion under the form of at least one hydroxide so as to obtain a precipitate comprising said at least one hydroxide and an aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion, and separating said aqueous composition comprising lithium sulphate and having said reduced content of said at least one metal ion from said precipitate; optionally reacting said aqueous composition comprising lithium sulphate and having said reduced content of said at least one metal ion with another base so as to obtain a pH of about 9.5 to about 11.5, and with optionally at least one metal carbonate, thereby 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 said at least one carbonate and an aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion, and separating said aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion from said precipitate; contacting said aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion with an ion exchange resin so as to at least partially remove at least one metal ion from said composition, thereby obtaining an aqueous composition comprising lithium sulphate; submitting said aqueous composition comprising said lithium sulphate to an electrodialysis or an electrolysis under conditions suitable for converting at least a portion of said lithium sulphate into lithium hydroxide; and converting said lithium hydroxide into lithium carbonate. leaching a sulphuric acid roasted lithium-containing material with water so as to obtain an aqueous composition comprising lithium sulphate and at least one metal ion; reacting said aqueous composition comprising lithium sulphate and said at least one metal ion with a base so as to obtain a pH of about 4.5 to about 6.5 and thereby at least partially precipitating said at least one metal ion under the form of at least one hydroxide so as to obtain a precipitate comprising said at least one hydroxide and an aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion, and separating said aqueous composition comprising lithium sulphate and having said reduced content of said at least one metal ion from said precipitate; optionally reacting said aqueous composition comprising lithium sulphate and having said reduced content of said at least one metal ion with another base so as to obtain a pH of about 9.5 to about 11.5, and with optionally at least one metal carbonate, thereby 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 said at least one carbonate and an aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion, and separating said aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion from said precipitate; contacting said aqueous composition comprising lithium sulphate and having a reduced content of said at least one metal ion with an ion exchange resin so as to at least partially remove at least one metal ion from said composition, thereby obtaining an aqueous composition comprising lithium sulphate; submitting said aqueous composition comprising said lithium sulphate to an electrodialysis or an electrolysis under conditions suitable for converting at least a portion of said lithium sulphate into lithium hydroxide; and converting said lithium hydroxide into lithium carbonate.