Method for producing high-purity nickel/cobalt mixed solutions for cathode materials using a 2-circuit process

Method for producing high-purity mixed solutions for cathode materials by simultaneously extracting nickel and cobalt using a 2-circuit process

This technology is a 2-circuit process that simultaneously extracts and separates nickel and cobalt using D2EHPA and Versatic Acid-10 extractants under specific pH and organic-to-aqueous (O/A) ratio conditions, eliminating the need for conventional 3-circuit extraction and crystallization processes.

The conventional 3-circuit process requires approximately 45 to 60 mixer-settler stages, leading to high capital expenditure, increased operating costs due to the additional crystallization step, excessive consumption of pH adjusters, and significant wastewater generation.

By simplifying the process into a 1st circuit (impurity removal) and a 2nd circuit (nickel/cobalt extraction) and applying optimized pH ranges (e.g., 3.4–3.6 for the 1st circuit, 6.2–6.4 for the 2nd circuit) and O/A ratios for each stage, this technology produces high-purity nickel/cobalt mixed solutions without a crystallization step, offering a practical solution for the development of next-generation lithium secondary battery cathode materials.

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Key Features:

• A 1st-circuit extraction process that uses a primary extractant to remove impurities, excluding magnesium, from sulfides containing nickel, cobalt, and magnesium.
• A 1st-circuit scrubbing process that recovers the co-extracted nickel and cobalt into an aqueous state by stirring the extracted organic solution with distilled water.
• A 2nd-circuit process that simultaneously extracts and separates nickel and cobalt using D2EHPA and Versatic Acid-10 extractants.
• A configuration that simplifies the process into 2 circuits by applying optimized pH ranges and organic-to-aqueous ratios for each stage.

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