Method for producing secondary battery material from black mass

1 . A method for producing a secondary battery material from black mass, comprising:

roasting black mass to produce roasted black mass;

leaching the roasted black mass with water to separate a first lithium (Li) solution and a cake;

producing lithium carbonate (Li2CO3) crystals by evaporating and concentrating the first lithium (Li) solution;

leaching the cake separated from the first lithium (Li) solution;

removing copper and aluminum from a leaching solution produced by the leaching of the cake, which includes removing of the copper by adding sodium hydrogen sulfide (NaHS) to the leaching solution and removing the aluminum by adding sodium hydroxide (NaOH) to the leaching solution;

neutralizing the leaching solution and separating the leaching solution into a second lithium (Li) solution and a cake containing Ni, Co, and Mn (“NCM cake”); and

feeding the lithium carbonate (Li2CO3) crystals and the second lithium (Li) solution produced by the separating of the leaching solution to a lithium hydroxide (LiOH) production process, which includes:

producing a lithium phosphate (Li3PO4) cake by adding phosphoric acid (H3PO4) and sodium hydroxide (NaOH) to the second lithium (Li) solution produced by the separating of the leaching solution,

preparing a lithium sulfate (Li2SO4) solution by co-leaching the lithium carbonate (Li2CO3) crystals and the lithium phosphate (Li3PO4) cake together with sulfuric acid,

precipitating lithium carbonate (Li2CO3) by adding sodium carbonate (Na2CO3) to the lithium sulfate (Li2SO4) solution,

preparing a lithium hydroxide (LiOH) solution by adding calcium oxide (CaO) and water to the lithium carbonate (Li2CO3), and

evaporating and concentrating the lithium hydroxide (LiOH) solution.

2 . The method of claim 1 , further comprising:

preparing a solution containing Ni, Co, and Mn (“NCM solution”) by leaching the NCM cake with sulfuric acid;

removing impurities from the NCM solution; and

feeding the NCM solution with the impurities removed to a factory that produces precursor raw materials.

3 . The method of claim 2 , further comprising:

removing residual sodium salt by repulping the NCM cake twice or more.

4 . The method of claim 1 , further comprising:

separating the lithium sulfate (Li 2 SO 4 ) solution into lithium sulfate (Li 2 SO 4 ) crystals and a phosphoric acid (H 3 PO 4 ) filtrate by evaporating and concentrating the lithium sulfate (Li 2 SO 4 ) solution.

5 . The method of claim 1 , further comprising:

removing residual sodium salt from a cake of lithium carbonate (Li 2 CO 3 ) produced by the precipitating of the lithium carbonate (Li 2 CO 3 ).

6 . The method of claim 1 , further comprising:

removing phosphorous (P), iron (Fe), and other impurities by adding aluminum sulfate (Al 2 (SO 4 ) 3 ) to the lithium sulfate (Li 2 SO 4 ) solution to control a pH to be from 5.0 to 6.0.

7 . The method of claim 1 ,

wherein 1.2 equivalents of the sodium hydrogen sulfide (NaHS) for removing the copper are added to the leaching solution at a temperature of 60 to 80 degrees C., and

wherein the removing of the aluminum is performed at a temperature of 70 to 85 degrees.

8 . The method of claim 1 ,

wherein aluminum precipitates as aluminum hydroxide (Al(OH) 3 by adding the sodium hydroxide (NaOH) to the leaching solution, and

wherein Fe and Si are co-precipitated with the aluminum hydroxide (Al(OH) 3 .

9 . The method of claim 1 , wherein the producing of the lithium phosphate (Li 3 PO 4 ) cake precipitates and recovers lithium (Li) in the form of lithium phosphate (Li 3 PO 4 ) by adding 1.2 equivalents of the phosphoric acid (H 3 PO 4 ) to the second lithium (Li) solution at a temperature of 70 to 85 degrees C.

10 . The method of claim 2 ,

wherein the removing of the impurities from the NCM solution includes removing copper and aluminum from the NCM solution to 5 mg/L or less, respectively,

wherein the removing of the copper from the NCM solution includes adding 1.2 equivalents of sodium hydrogen sulfide (NaHS) to the NCM solution at a temperature of 60 to 80 degrees C., and

wherein the removing of the aluminum from the NCM solution occurs at a temperature of 70 to 85 degrees cat a pH of 4.0 to 5.5.

11 . The method of claim 2 ,

wherein the removing of impurities from the NCM solution includes removing copper and aluminum from the NCM solution to 5 mg/L or less, respectively,

wherein the removing of the copper from the NCM solution includes adding 1.2 equivalents of sodium hydrogen sulfide (NaHS) to the NCM solution at a temperature of 60 to 80 degrees C., and

wherein the removing of the aluminum from the NCM solution occurs at a temperature of 70 to 85 degrees C. at a pH 4.0 to 5.5.

12 . The method of claim 1 , wherein evaporation condensate generated in the producing of lithium carbonate (Li 2 CO 3 ) crystals and in the evaporating and concentrating of the lithium hydroxide (LiOH) solution is recycled as a process solution for the leaching of the roasted black mass.