Processing method of positive electrode active substance waste of lithium ion secondary battery
A method for processing positive electrode active material waste of lithium ion secondary batteries, the waste containing cobalt, nickel, manganese and lithium, the method including: a carbon mixing step of mixing the positive electrode active material waste in the form of powder with carbon to obtain a mixture having a ratio of a mass of carbon to a total mass of the positive electrode active material waste and the carbon of from 10% to 30%; a roasting step of roasting the mixture at a temperature of from 600° C. to 800° C. to obtain roasted powder; a dissolution step including a first dissolution process of dissolving lithium in the roasted powder in water or a lithium-containing solution, and a second dissolution process of dissolving the lithium in a residue obtained in the first dissolution process in water; and an acid leaching step of leaching a residue obtained in the lithium dissolution step with an acid.
1. A method for processing positive electrode active material waste of lithium ion secondary batteries, the waste containing cobalt, nickel, manganese and lithium, the method comprising:
a carbon mixing step of mixing the positive electrode active material waste in the form of powder with carbon to obtain a mixture having a ratio of a mass of carbon to a total mass of the positive electrode active material waste and the carbon of from 10% to 30%;
a roasting step of roasting the mixture at a temperature of from 600° C. to 800° C. to obtain roasted powder;
a lithium dissolution step including a first dissolution process of dissolving lithium in the roasted powder in water or a lithium-containing solution to produce a lithium solution, and a second dissolution process of dissolving the lithium in a residue obtained in the first dissolution process in water; and
an acid leaching step of leaching a residue obtained in the lithium dissolution step with an acid.
2. The method for processing positive electrode active material waste according to claim 1 , wherein the positive electrode active material waste further comprises at least one of aluminum and iron as an impurity, and
wherein the method further comprises a neutralization step of neutralizing a leached solution obtained in the acid leaching step to separate at least a part of the impurity.
3. The method for processing positive electrode active material waste according to claim 2 , further comprising a Mn extraction step of separating manganese from the leached solution obtained in the acid leaching step by solvent extraction.
4. The method for processing positive electrode active material waste according to claim 3 ,
wherein the Mn extraction step comprises separating at least a part of the impurity from the leached solution by solvent extraction.
5. The method for processing positive electrode active material waste according to claim 3 , further comprising a Co recovery step of extracting and back-extracting cobalt by solvent extraction from a neutralized solution obtained in the neutralization step or a Mn extracted solution obtained in the Mn extraction step to obtain electric cobalt by electrowinning.
6. The method for processing positive electrode active material waste according to claim 5 , wherein the Co recovery step comprises dissolving the electric cobalt obtained by electrowinning in sulfuric acid, hydrochloric acid or nitric acid to recover cobalt in the form of a salt of sulfuric acid, hydrochloric acid or nitric acid.
7. The method for processing positive electrode active material waste according to claim 5 , further comprising a Ni recovery step of extracting and back-extracting nickel by solvent extraction from a Co extracted solution obtained by extracting cobalt from the neutralized solution or the Mn extracted solution in the Co recovery step to obtain electrolytic nickel by electrowinning.
8. The method for processing positive electrode active material waste according to claim 7 , wherein the Ni recovery step comprises dissolving the electrolytic nickel obtained by electrowinning in sulfuric acid, hydrochloric acid or nitric acid to recover nickel in the form of a salt of sulfuric acid, hydrochloric acid or nitric acid.
9. The method for processing positive electrode active material waste according to claim 3 , further comprising a Co/Ni recovery step of extracting and back-extracting cobalt and nickel by solvent extraction from a neutralized solution obtained in the neutralization step or a Mn extracted solution obtained in the Mn extraction step to obtain a mixed solution of sulfuric acid, hydrochloric acid or nitric acid in which cobalt and nickel have been dissolved.
10. The method for processing positive electrode active material waste according to claim 1 , wherein lithium in a lithium dissolved solution obtained in the lithium dissolution step is recovered as lithium carbonate or lithium hydroxide.
11. The method for processing positive electrode active material waste according to claim 1 , wherein a lithium dissolved solution obtained in the lithium dissolution step is used as the lithium-containing solution for dissolving lithium in the roasted powder in the first dissolution process.
12. The method for processing positive electrode active material waste according to claim 1 , wherein the first dissolution process is continued until a lithium concentration in the lithium solution reaches 2 g/L or more.
13. The method for processing positive electrode active material waste according to claim 1 , further comprising a Mn extraction step of separating manganese from a leached solution obtained in the acid leaching step by solvent extraction.
14. The method for processing positive electrode active material waste according to claim 13 ,
wherein the positive electrode active material waste further comprises at least one of aluminum and iron as an impurity, and
wherein the Mn extraction step comprises separating at least a part of the impurity from the leached solution by solvent extraction.