Mixed Metal Extraction pH Control for Battery Leachate Purity
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Solution Overview
Problem
Existing metal recovery processes from lithium ion battery waste fail to produce high-purity mixed metal solutions or salts containing manganese, cobalt, and nickel due to the extraction of aluminum ions, which lowers the purity and complicates the process.
Innovation Solution
A method involving an Al removal step to extract aluminum ions into a solvent while maintaining manganese ions in the aqueous phase, followed by a metal extraction step using a carboxylic acid-based extracting agent to extract cobalt and nickel ions, and a back-extraction step to obtain a high-purity mixed metal solution, and a precipitation step to form mixed metal salts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If aluminum ions are extracted into a solvent during the first solvent extraction step, then aluminum removal is achieved, but manganese ions are also extracted along with aluminum, resulting in a deficiency of manganese in the final metal mixed solution or mixed metal salts
Solution Approach 1:
The patent divides the extraction process into two distinct stages: (1) an Al removal step using a specific extracting agent that selectively extracts aluminum while leaving manganese in the aqueous phase, and (2) a subsequent metal extraction step that extracts cobalt, nickel, and manganese. This segmentation allows independent optimization of aluminum removal without compromising manganese content.
Solution Approach 2:
The patent utilizes parameter changes, specifically pH control, to achieve selective extraction. By adjusting the pH to a specific range during the Al removal step, the extracting agent selectively binds aluminum ions while manganese ions remain in the aqueous phase. This parameter control enables differentiation between metal ions based on their extraction behavior at specific pH conditions.
2Quantity of substance
If aluminum ions are not sufficiently extracted and removed, then manganese content is preserved, but aluminum remains as an impurity in the metal mixed solution or mixed metal salts, decreasing the purity
Solution Approach 1:
The patent segments the extraction process into distinct functional steps: first removing aluminum through selective extraction at controlled pH, then subsequently extracting the desired metals (cobalt, nickel, manganese). This segmentation ensures that aluminum removal does not compromise manganese retention, as each step is optimized for its specific function.
Solution Approach 2:
The patent employs parameter changes, specifically controlling pH within a specific range during the Al removal step, to achieve selective aluminum extraction while preserving manganese. By adjusting this critical parameter, the process achieves high aluminum removal efficiency without sacrificing manganese content, thereby simultaneously improving purity and maintaining quantity.
3Manufacturing precision
If multiple separate extraction steps are used to remove aluminum and then extract cobalt, nickel, and manganese, then purity is improved, but the process complexity and cost increase
Solution Approach 1:
The patent merges the aluminum removal function and the metal extraction function into a unified two-step process using a single type of extracting agent (carboxylic acid-based). By combining these functions and using the same agent type for both steps, the process achieves high purity while reducing complexity compared to using multiple different extracting agents and procedures.
Solution Approach 2:
The patent employs a carboxylic acid-based extracting agent that serves multiple functions: it selectively removes aluminum in the first step and then extracts cobalt, nickel, and manganese in the second step. This multi-functionality of a single agent type simplifies the overall process compared to using different specialized agents for each metal, thereby reducing device complexity while maintaining manufacturing precision.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method effectively produces high-purity mixed metal solutions and salts, simplifying the process and reducing costs by omitting electrolysis, and enabling direct use in producing cathode materials for lithium ion batteries.
Implementation Method 1
extracting the aluminum ions into a solvent while leaving at least a part of the manganese ions in the acidic solution in an aqueous phase
Implementation Method 2
bringing an extracted residual liquid obtained in the Al removal step to an equilibrium pH of 6.5 to 7.5 using a solvent comprising a carboxylic acid-based extracting agent, extracting at least one of the manganese ions and at least one of the cobalt ions and the nickel ions into the solvent
Data Source
AI summary
A method for producing a mixed metal solution containing manganese ions and at least one of cobalt ions and nickel ions, the method including: an Al removal step of subjecting an acidic solution containing at least manganese ions and aluminum ions, and at least one of cobalt ions and nickel ions, to removal of the aluminum ions by extracting the aluminum ions into a solvent while leaving at least a part of the manganese ions in the acidic solution in an aqueous phase, the acidic solution being obtained by subjecting battery powder of lithium ion batteries to a leaching step; and a metal extraction step of bringing an extracted residual liquid obtained in the Al removal step to an equilibrium pH of 6.5 to 7.5 using a solvent containing a carboxylic acid-based extracting agent, extracting at least one of the manganese ions and at least one of the cobalt ions and the nickel ions into the solvent, and then back-extracting the manganese ions and at least one of the cobalt ions and nickel ions.