Method for recovering valuable metals from waste lithium-ion batteries

Process for separating valuable metals from waste battery alloys using combined NaClO oxidative precipitation and oxalate precipitation

This technology is a process for separating and recovering valuable metals by dissolving molten-reduced waste battery alloys in an acidic leachate, followed by copper displacement using iron powder, multi-stage solvent extraction of Fe(III), selective oxidative precipitation of manganese and cobalt, and oxalate precipitation of nickel.

Some extractants used in conventional hydrometallurgical processes have limited utility due to low metal selectivity and environmental toxicity. Furthermore, they face limitations such as poor separation efficiency between metal ions and the formation of fine precipitates, which complicates the filtration process.

This technology involves adding a NaClO oxidizing agent to the filtrate after Fe(III) removal to sequentially precipitate Mn(II) as MnO2 and Co(II) as Co2O3, and finally reacting Ni(II) with oxalate to precipitate it as NiC2O4. Applicable to hybrid dry-wet battery recycling plants and nickel-cobalt precursor material regeneration, it enables the sequential acquisition of high-purity metal intermediates while reducing the use of hazardous extractants.

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Key Features:

• A leaching solution preparation step of dissolving copper, nickel, cobalt, and manganese from an alloy phase produced by molten reduction of waste lithium batteries using ferric chloride or ferric sulfate extractant
• A copper recovery step of adding iron powder to the leaching solution to precipitate and recover copper ions through a displacement reaction
• An iron removal step of oxidizing Fe(II) ions to Fe(III) ions with a primary oxidizing agent and removing the Fe(III) ions via solvent extraction
• A sequential precipitation step of oxidizing and precipitating Mn(II) as MnO2 using NaClO at a molar ratio of 3.0–4.5, and Co(II) as Co2O3 at a ratio of 4.5–7.5

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This invention was developed with support from the Ministry of Trade, Industry and Energy for the development of commercial-scale high-temperature reduction melting and concentration/separation technology for recovering valuable metals from medium-to-large waste lithium-ion batteries (2,000 tons/year).

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