Valuable metal leaching method, and valuable metal collection method employing the leaching method
AssigneeSumitomo Metal Mining Co., Ltd.
InventorsHitoshi Ishida, Yukie Kawakami, Keiji Kudo, Satoshi Asano
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Abstract
The present invention provides a valuable metal leaching method and a valuable metal collection method, in each of which valuable metals can be leached efficiently, the amount of a reducing agent used can be reduced, and cost reduction can be achieved. In the present invention, a positive electrode material is immersed in an acidic solution together with a metal having a lower reduction potential than a reduction potential of hydrogen, whereby valuable metals are leached out from a positive-electrode active substance.
Claims7
A valuable metal leaching method of leaching out valuable metals comprising nickel, cobalt, and lithium contained in a positive electrode material of a lithium ion battery,
- wherein the positive electrode material is immersed in an acidic solution together with a metal having a lower reduction potential than a reduction potential of hydrogen, whereby the valuable metals are leached out from a positive-electrode active substance,
- wherein the metal having a lower reduction potential than a reduction potential of hydrogen is nickel metal obtained from a nickel-metal hydride battery,
- wherein an alkali sulfate is added to a leachate obtained by a leaching step, thereby removing a rare earth element contained in said leachate as a double sulfate, and
- wherein a sulfurizing agent is added to a mother liquor obtained through a rare earth element removal step, and, with adjusting a pH of said mother liquor to 2 to 5, a mixed sulfide of nickel and cobalt is formed.
A valuable metal collection method of collecting valuable metals comprising nickel, cobalt, and lithium contained in a positive electrode material of a lithium ion battery, the method comprising:
- a leaching step of leaching out the valuable metals from a positive-electrode active substance by immersing the positive electrode material in an acidic solution together with a metal having a lower reduction potential than a reduction potential of hydrogen,
- wherein the metal having a lower reduction potential than a reduction potential of hydrogen is nickel metal obtained from a nickel-metal hydride battery,
- a rare earth element removal step, wherein an alkali sulfate is added to a leachate obtained by the leaching step, thereby removing a rare earth element contained in said leachate as a double sulfate, and
- a sulfurizing step, wherein a sulfurizing agent is added to a mother liquor obtained through the rare earth element removal step, and, with adjusting a pH of said mother liquor to 2 to 5, a mixed sulfide of nickel and cobalt is formed.
Dependencies are inferred from the claim text.