Simplified solvent extraction process for high-purity Ni/Co mixed solution for lithium–ion batteries

ABSTRACT

The demands for Ni-based raw materials increase as Ni–Co–Mn ternary cathode materials become the main axis of the battery industry. Conventional hydrometallurgical process to produce raw materials from Ni ore for battery application is as follows: (i) leaching of metal ions by acid, (ii) solvent extraction process to extract target metals, and (iii) crystallization process to produce final single-metal compound as powder products. The conventional solvent extraction process is a three-circuit process comprising impurity removal, Co extraction, and Ni extraction circuits. Unlike conventional process, in this work, we suggest a simplified two-circuit process to simultaneously extract Ni and Co to produce Ni/Co mixed solution for cathode material precursor production. Accordingly, the efficiency of site utilization can be maximized by reducing the investment cost for the manufacturing process and downsizing mixer-settler facilities. Further, eco-friendly effects such as reducing the consumption of titrants and cutting down the process costs and wastewater discharge can be realized.

KEYWORDS:

• Nickel
• cobalt
• solvent extraction
• D2EHPA
• VA10

Disclosure statement

No potential conflict of interest was reported by the authors.

Author contributions

Conceptualization: Yong-Tae Kim and Gogwon Choe

Methodology: Yong-Tae Kim, Gogwon Choe, Young-Jin Lim, and Younghyun Kim

Investigation: Gogwon Choe, Young-Jin Lim, and Younghyun Kim

Funding acquisition: Yong-Tae Kim

Writing – original draft: Gogwon Choe and Young-Jin Lim

Writing – review and editing: All authors

Statement of novelty

In this work, we describe a simplified method for separating nickel (Ni) and cobalt (Co) from a type of Ni ore leachate called mixed hydroxide precipitate (MHP) to produce battery materials. The conventional method involves a three-circuit process to separate Ni and Co, while the simplified method is a two-circuit process that can extract Ni and Co simultaneously, reducing the number of stages required. This allows to produce Ni/Co mixed solutions without crystallization, which can be used to produce hydroxide precursor for battery materials. This new approach is promising for increasing efficiency, reducing cost, and minimizing environmental impact.

Additional information

Funding

The work was supported by the grants from Korea Institute of Energy Technology Evaluation and Planning [20217510100020] and National Research Foundation of Korea [2019M3D1A1079306].