Method for separating rare earth elements contained in nickel metal hydride battery and method for recovering valuable metals from nickel metal hydride battery

摘要

PROBLEM TO BE SOLVED: To provide a method for separating rare earth elements contained in a nickel-hydrogen battery in which rare earth elements can be efficiently separated, while leaching nickel at high leaching ratio when recovering nickel and rare earth elements of valuable metals from a negative electrode component of the nickel-hydrogen battery, and to provide a method for recovering valuable metals from the nickel-hydrogen battery using the method.SOLUTION: When recovering nickel and rare earth elements of valuable metals from a negative electrode component of a nickel-hydrogen battery, a sulfuric acid solution whose concentration is adjusted so as to fluctuate within a range from a solubility equal to or greater than a solubility of the rare earth elements contained in a negative electrode component to a solubility equal to or less than a solubility of nickel is added to the negative electrode component to leach valuable metals from the negative electrode component. The resultant leaching slurry is separated into a leaching solution and a leaching residue. The rare earth elements dissolved in the leaching solution are separated by adding de rare earth agent to the leaching solution.