Lithium-ion battery recycling method

Nickel and Cobalt Selective Separation Process for Spent Batteries Combining Carbonaceous Reduction Roasting and Magnetic Separation

This technology involves reduction roasting of spent lithium-ion battery powder with a carbonaceous reducing agent at 600–680°C. It converts non-magnetic cathode composite metal oxides into magnetic single metal oxides, such as nickel and cobalt, which are then separated via magnetic sorting to ensure the efficiency and stability of the multi-stage leaching process.

Conventional methods suffer from low acid leaching rates for nickel and cobalt in cathode materials, necessitating the constant addition of expensive reducing agents like hydrogen peroxide. This leads to process instability and inefficient consumption of reducing agents.

This technology mixes battery powder with a carbonaceous reducing agent, such as activated carbon, at a 3–4 molar ratio relative to the cathode material. After reduction roasting to restore metal magnetism, nickel and cobalt components are isolated through solid-liquid separation and magnetic sorting, allowing only these fractions to proceed to the secondary leaching stage. Applicable to cell manufacturing scrap and black mass pretreatment lines, it enables the recycling of anode graphite as a reducing agent while concentrating the use of expensive chemical reagents only where necessary.

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Key Features:

• A reduction roasting step where battery powder is mixed with a carbonaceous reducing agent at a 3–4 molar ratio to the cathode material and heated to reduce individual metals into oxide forms
• A step of reacting the roasted battery powder with an acid solution to leach metals, followed by solid-liquid separation to remove unleached residue
• A magnetic separation step to isolate magnetic metals, such as cobalt and nickel oxides, from the solid battery powder residue
• A secondary leaching step where a reducing agent is added to the acid solution to reduce and acid-leach the magnetically separated metals

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of advanced hydrometallurgical technologies to increase the value of recovered resources.

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