METHOD FOR RECOVERING METALS FROM LITHIUM ION BATTERY WASTE
Provided is a method for efficiently recovering metals from lithium ion battery waste while reducing the use of sodium hydroxide as a pH adjuster. A method for recovering metals from lithium ion battery waste includes wet processing of leaching metals containing lithium from lithium ion battery waste with an acid, and extracting the metals from the metal-containing solution in which the metals are dissolved, in which the lithium extracted in the wet processing is used as a pH adjuster used in the wet processing.
1 . A method for recovering metals from lithium ion battery waste, comprising
wet processing of leaching metals containing lithium from lithium ion battery waste with an acid, and extracting the metals from a metal-containing solution in which the metals are dissolved,
wherein the lithium extracted in the wet processing is used as a pH adjuster used in the wet processing.
2 . The metal recovery method according to claim 1 , wherein the lithium is extracted as a lithium hydroxide aqueous solution in the wet processing, and the lithium hydroxide aqueous solution is used as the pH adjuster.
3 . The metal recovery method according to claim 1 , wherein lithium extracted in the wet processing is used as all of the alkaline pH adjusters used in the wet processing.
4 . The metal recovery method according to claim 1 , wherein all alkaline pH adjusters used in the wet processing are sodium-free.
5 . The metal recovery method according to claim 1 ,
wherein the wet processing comprises an acid leaching step of leaching metals comprising lithium from the lithium ion battery waste with an acid to obtain the metal-containing solution, and one or more extraction steps of separating the metals from the metal-containing solution by solvent extraction,
wherein lithium extracted in the wet processing is used as a pH adjuster used in at least one of the extraction steps.
6 . The metal recovery method according to claim 5 ,
wherein the metals comprise cobalt, nickel, and manganese,
the extraction step includes a manganese extraction step, a cobalt extraction step, and a nickel extraction step in this order, and
lithium used as a pH adjuster used in the wet processing is extracted from the extraction residue obtained in the nickel extraction step.
7 . The metal recovery method according to claim 6 ,
wherein the extraction residue is a lithium sulfate aqueous solution, and
the nickel extraction step is followed by a hydroxylation step to obtain a lithium hydroxide aqueous solution from the lithium sulfate aqueous solution.
8 . The metal recovery method according to claim 7 , wherein a part of the lithium sulfate aqueous solution is used in the hydroxylation step, and the remainder is used as at least a part of the acid in the acid leaching step.
9 . The metal recovery method according to claim 7 , wherein a series of steps including an acid leaching step, a manganese extraction step, a cobalt extraction step, a nickel extraction step, and a hydroxylation step is repeatedly performed over a plurality of times, and at least a part of the lithium is circulated in the solution in the series of steps.
10 . The metal recovery method according to claim 9 ,
wherein the repetition of the series of steps feeds metals in the lithium ion battery waste into the series of steps, which in turn increases the lithium ion concentration in the solution, and
the hydroxylation step is followed by a precipitation step to precipitate lithium hydroxide from a part of the lithium hydroxide aqueous solution according to the lithium ion concentration in the solution.
11 . The metal recovery method according to claim 6 ,
wherein the cobalt extraction step and the nickel extraction step each comprise extracting metal ions in the metal-containing solution into a solvent and back-extracting the metal ions in the solvent with a sulfuric acid solution, and
the cobalt extraction step and the nickel extraction step are each followed by a crystallization step to crystallize the metal ions in the back-extracted solution to obtain a sulfate.
12 . The metal recovery method according to claim 1 ,
wherein the wet processing is preceded by dry processing to obtain battery powder by processing comprising roasting of lithium ion battery waste, and
the battery powder is subjected to acid leaching in the wet processing to obtain the metal-containing solution.
13 . The metal recovery method according to claim 2 , wherein lithium extracted in the wet processing is used as all of the alkaline pH adjusters used in the wet processing.
14 . The metal recovery method according to claim 2 , wherein all alkaline pH adjusters used in the wet processing are sodium-free.
15 . The metal recovery method according to claim 2 ,
wherein the wet processing comprises an acid leaching step of leaching metals comprising lithium from the lithium ion battery waste with an acid to obtain the metal-containing solution, and one or more extraction steps of separating the metals from the metal-containing solution by solvent extraction,
wherein lithium extracted in the wet processing is used as a pH adjuster used in at least one of the extraction steps.
16 . The metal recovery method according to claim 2 ,
wherein the wet processing is preceded by dry processing to obtain battery powder by processing comprising roasting of lithium ion battery waste, and
the battery powder is subjected to acid leaching in the wet processing to obtain the metal-containing solution.