A method for dissolving a lithium compound according to the present invention includes bringing a lithium compound into contact with water or an acidic solution, and feeding, separately from the lithium compound, a carbonate ion to the water or the acidic solution to produce carbonic acid, and allowing the carbonic acid to react with the lithium compound to produce lithium hydrogen carbonate.

A method of forming lithium carbonate from a lithium-bearing solution including: evaporating the lithium-bearing solution to precipitate a first group of impurities; removing the first group of impurities to form a first purified solution; and performing a flash crystallisation step within a predetermined temperature range to crystallise a second group of impurities from the first purified solution; removing the second group of impurities from the first solution to form a second purified solution, wherein at least 90 wt % of lithium is recovered from the first purified solution; and reacting the second purified solution with a metal carbonate to form lithium carbonate of at least 90 wt % purity.

A method of forming lithium carbonate from a lithium-bearing solution including: evaporating the lithium-bearing solution to precipitate a first group of impurities; removing the first group of impurities to form a first purified solution; and performing a flash crystallisation step within a predetermined temperature range to crystallise a second group of impurities from the first purified solution; removing the second group of impurities from the first solution to form a second purified solution, wherein at least 90 wt % of lithium is recovered from the first purified solution; and reacting the second purified solution with a metal carbonate to form lithium carbonate of at least 90 wt % purity.

Disclosed is a method of producing high-purity lithium carbonate and barium sulfate from discarded lithium secondary batteries, including: a first process for producing high-purity lithium phosphate from a discarded battery; and a second process for producing lithium sulfate from the lithium phosphate and producing lithium carbonate and barium sulfate from the lithium sulfate. The second process has steps of (a) producing a liquid mixture of lithium phosphate and sulfuric acid, (b) obtaining lithium sulfate by condensing the liquid mixture, (c) dissolving the lithium sulfate in water or a sodium hydroxide aqueous solution, depositing phosphoric acid as lithium phosphate, and performing solid-liquid separation (d) depositing lithium carbonate and performing solid-liquid separation to obtain lithium carbonate, (e) finely grinding the lithium carbonate and classifying the particles, (f) controlling a particle size and shape by dissolving edges of particles or minute particles, (g) performing solid-liquid separation, and (h) depositing barium sulfate.

Disclosed is a method of producing high-purity lithium carbonate and barium sulfate from discarded lithium secondary batteries, including: a first process for producing high-purity lithium phosphate from a discarded battery; and a second process for producing lithium sulfate from the lithium phosphate and producing lithium carbonate and barium sulfate from the lithium sulfate. The second process has steps of (a) producing a liquid mixture of lithium phosphate and sulfuric acid, (b) obtaining lithium sulfate by condensing the liquid mixture, (c) dissolving the lithium sulfate in water or a sodium hydroxide aqueous solution, depositing phosphoric acid as lithium phosphate, and performing solid-liquid separation (d) depositing lithium carbonate and performing solid-liquid separation to obtain lithium carbonate, (e) finely grinding the lithium carbonate and classifying the particles, (f) controlling a particle size and shape by dissolving edges of particles or minute particles, (g) performing solid-liquid separation, and (h) depositing barium sulfate.

Disclosed is a method of producing high-purity lithium carbonate and barium sulfate from discarded lithium secondary batteries, including: a first process for producing high-purity lithium phosphate from a discarded battery; and a second process for producing lithium sulfate from the lithium phosphate and producing lithium carbonate and barium sulfate from the lithium sulfate. The second process has steps of (a) producing a liquid mixture of lithium phosphate and sulfuric acid, (b) obtaining lithium sulfate by condensing the liquid mixture, (c) dissolving the lithium sulfate in water or a sodium hydroxide aqueous solution, depositing phosphoric acid as lithium phosphate, and performing solid-liquid separation (d) depositing lithium carbonate and performing solid-liquid separation to obtain lithium carbonate, (e) finely grinding the lithium carbonate and classifying the particles, (f) controlling a particle size and shape by dissloving edges of particles or minute particles, (g) performing solid-liquid separation, and (h) depositing barium sulfate.

Disclosed is a method of producing high-purity lithium carbonate and barium sulfate from discarded lithium secondary batteries, including: a first process for producing high-purity lithium phosphate from a discarded battery; and a second process for producing lithium sulfate from the lithium phosphate and producing lithium carbonate and barium sulfate from the lithium sulfate. The second process has steps of (a) producing a liquid mixture of lithium phosphate and sulfuric acid, (b) obtaining lithium sulfate by condensing the liquid mixture, (c) dissolving the lithium sulfate in water or a sodium hydroxide aqueous solution, depositing phosphoric acid as lithium phosphate, and performing solid-liquid separation (d) depositing lithium carbonate and performing solid-liquid separation to obtain lithium carbonate, (e) finely grinding the lithium carbonate and classifying the particles, (f) controlling a particle size and shape by dissloving edges of particles or minute particles, (g) performing solid-liquid separation, and (h) depositing barium sulfate.

A method for dissolving a lithium compound according to the present invention includes bringing a lithium compound into contact with water or an acidic solution, and feeding, separately from the lithium compound, a carbonate ion to the water or the acidic solution to produce carbonic acid, and allowing the carbonic acid to react with the lithium compound to produce lithium hydrogen carbonate.

A process for alumina and carbonate production from aluminium rich materials with integrated CO.sub.2 utilization, comprising: comminuting and leaching Al-rich materials in concentrated HCl; separating unreacted material from metal chloride solution; separating Al.sup.3+ from solution by crystallization of AlCl.sub.3.6H.sub.2O; calcination of AlCl.sub.3.6H.sub.2O with HCl recovery; precipitation of metal carbonates from CO.sub.2; regeneration of HCl and extractive amines; the Al.sup.3+ separation the facilitated by increasing HCl concentration; the calcination being performed in two steps, one in the range 400 and 600? C. to generate a HCl-rich gas and one above 600? C. to produce Al.sub.2O.sub.3; for precipitating metal carbonates, mixing the metal chloride solution with an organic solution containing a selected amine and contacting the mixture with a CO.sub.2-containing gas, thereby also extracting HCl by formation of an ammonium chloride salt complex; processing thermally or chemically the organic solution to regenerate the amine for recirculation.

A process for alumina and carbonate production from aluminium rich materials with integrated CO.sub.2 utilization, comprising: comminuting and leaching Al-rich materials in concentrated HCl; separating unreacted material from metal chloride solution; separating Al.sup.3+ from solution by crystallization of AlCl.sub.3.6H.sub.2O; calcination of AlCl.sub.3.6H.sub.2O with HCl recovery; precipitation of metal carbonates from CO.sub.2; regeneration of HCl and extractive amines; the Al.sup.3+ separation the facilitated by increasing HCl concentration; the calcination being performed in two steps, one in the range 400 and 600? C. to generate a HCl-rich gas and one above 600? C. to produce Al.sub.2O.sub.3; for precipitating metal carbonates, mixing the metal chloride solution with an organic solution containing a selected amine and contacting the mixture with a CO.sub.2-containing gas, thereby also extracting HCl by formation of an ammonium chloride salt complex; processing thermally or chemically the organic solution to regenerate the amine for recirculation.