Nickel-metal hydride (NiMH) battery recycling
AssigneeAscend Elements, Inc.
InventorsKee-Chan Kim, Matthew Eggert
Life of this patent
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Abstract
Recycling of nickel-metal hydride (NiMH) batteries extracts substantially pure nickel based on adding a leach agent to granular cathode material resulting from agitation of the NiMH batteries to form a leach solution. A pH of the leach solution is maintained for precipitating iron, aluminum and lanthanide rare earth elements (REE) for yielding a nickel solution for forming a cathode material precursor in a recycled battery, often with a high nickel content.
Claims13
A method of recycling nickel-metal hydride (NiMH) batteries, comprising:
- combining a leach agent and granular cathode material resulting from agitation of the NiMH batteries to form a leach solution;
- and
- adjusting or maintaining a pH of the leach solution to between 5 and 6 for precipitating and removing impurities comprising iron, aluminum and lanthanide rare earth elements (REE) for yielding a nickel solution.
A method of recycling nickel-metal hydride (NiMH) batteries, comprising:
- combining a leach agent and granular cathode material resulting from agitation of the NiMH batteries to form a leach solution;
- adjusting or maintaining a pH of the leach solution for precipitating impurities comprising iron, aluminum and lanthanide rare earth elements (REE) for yielding a nickel solution;
- stirring the leach solution for at least 5 hours for dissolving nickel and cobalt in the leach solution;
- following dissolution of the nickel and cobalt, adjusting or maintaining the pH of the leach solution between 5 and 6 for precipitating Fe and Al;
- and
- filtering precipitated impurities including the Fe and Al for recovering the dissolved nickel and cobalt in the leach solution.
A method of recycling nickel-metal hydride (NiMH) batteries, comprising:
- receiving a black mass in a recycling stream including granular cathode material resulting from agitation of the NiMH batteries;
- adding sulfuric acid of a 2-5 M concentration to the black mass to form a leach solution;
- adding hydrogen peroxide in an amount of 0.2-0.6 volume ratio to the weight of black mass to the leach solution;
- stirring the leach solution for at least 5 hours while maintaining a pH of the leach solution between 5-6 for precipitating impurities including iron and aluminum from the leach solution;
- filtering the leach solution to remove precipitated solid of the impurities;
- adding sulfuric acid of a concentration between 93%-98% and sodium hydroxide of a concentration between 25%-50% to adjust the pH of the leach solution between 1-3 for precipitating REEs (rare earth elements) remaining in the leach solution;
- precipitating a double sulfate salt of the REEs as a crystalline powder;
- filtering the REEs from the leach solution;
- and
- crystallizing excess sodium sulfate to achieve a nickel ion concentration between 1.1 M-1.7 M in the leach solution.
Dependencies are inferred from the claim text.