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.

A method according to an embodiment is for recovering a valuable metal from a waste electrode material of a lithium secondary battery by using lithium carbonate. An anode-cathode mixed electrode material that has been separated by draining, crushing, screening, and sorting a waste lithium secondary battery is preprocessed. A precipitation operation performed by adding lithium carbonate (Li2CO3) to a metal melt acquired by performing sulfuric acid dissolution using sulfuric acid. A valuable metal such as nickel, cobalt, manganese, aluminum, and copper is recovered as a residue in the form of a carbonate composite, and a lithium sulfate (Li2SO4) aqueous solution including lithium is recovered as a filtrate.

This disclosure relates to a method of preparing a lithium compound that includes preparing a lithium phosphate, mixing the lithium phosphate with sulfuric acid to obtain a mixture, converting the lithium phosphate into lithium sulfate through a reaction in the mixture, and separating the lithium sulfate in a solid phase, wherein in the step of converting the lithium phosphate into lithium sulfate through the reaction in the mixture, a sum concentration ([P+S] mol/L) of phosphorus (P) and sulfur (S) in a liquid phase of the mixture is greater than or equal to 5 mol/L.

This disclosure relates to a method of preparing a lithium compound that includes preparing a lithium phosphate, mixing the lithium phosphate with sulfuric acid to obtain a mixture, converting the lithium phosphate into lithium sulfate through a reaction in the mixture, and separating the lithium sulfate in a solid phase, wherein in the step of converting the lithium phosphate into lithium sulfate through the reaction in the mixture, a sum concentration ([P+S] mol/L) of phosphorus (P) and sulfur (S) in a liquid phase of the mixture is greater than or equal to 5 mol/L.

Systems and methods using solar evaporation to preconcentrate lithium containing brines to at or near lithium saturation, followed by a separation processes to separate lithium from impurities. A separated impurity stream is recycled to a point in the evaporation sequence where conditions are favorable for their precipitation and removal or disposed in a separate evaporation pond or reinjected underground, while a lower impurity stream is transferred to one or more of the removal location, to a subsequent pond in the sequence, or to a lithium plant or concentration facility. Further concentration of lithium by evaporation can then take place because impurities are removed thus eliminating lithium losses due to co-precipitation and achieving significantly higher concentrations of lithium.

Systems and methods using solar evaporation to preconcentrate lithium containing brines to at or near lithium saturation, followed by a separation processes to separate lithium from impurities. A separated impurity stream is recycled to a point in the evaporation sequence where conditions are favorable for their precipitation and removal or disposed in a separate evaporation pond or reinjected underground, while a lower impurity stream is transferred to one or more of the removal location, to a subsequent pond in the sequence, or to a lithium plant or concentration facility. Further concentration of lithium by evaporation can then take place because impurities are removed thus eliminating lithium losses due to co-precipitation and achieving significantly higher concentrations of lithium.

The present invention relates to recovery of lithium from liquid resources to produce lithium solutions while limiting impurity precipitation in the lithium solutions.

The present invention relates to recovery of lithium from liquid resources to produce lithium solutions while limiting impurity precipitation in the lithium solutions.

The present invention provides a method for producing a bis (fluorosulfonyl) imide alkali metal salt by a reaction of a mixture containing bis (fluorosulfonyl) imide and an alkali metal compound is provided. According to this method for producing a bis (fluorosulfonyl) imide alkali metal salt, a total of weight ratios of the bis (fluorosulfonyl) imide, the alkali metal compound and the bis (fluorosulfonyl) imide alkali metal salt to an entire reacted mixture is not less than 0.8, after the reaction.

The present invention provides a method for producing a bis (fluorosulfonyl) imide alkali metal salt by a reaction of a mixture containing bis (fluorosulfonyl) imide and an alkali metal compound is provided. According to this method for producing a bis (fluorosulfonyl) imide alkali metal salt, a total of weight ratios of the bis (fluorosulfonyl) imide, the alkali metal compound and the bis (fluorosulfonyl) imide alkali metal salt to an entire reacted mixture is not less than 0.8, after the reaction.