Positive Electrode Recycling via Pressurized CO2 Leaching
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Solution Overview
Problem
Conventional methods for recycling lithium ion secondary battery materials fail to efficiently separate lithium (Li) and aluminum (Al) from waste positive electrodes, requiring multiple separation steps due to their simultaneous leaching with transition metals like nickel (Ni), cobalt (Co), and manganese (Mn).
Innovation Solution
A method involving bringing waste positive electrodes containing Li and Al into contact with water under pressurized CO2 conditions to facilitate selective leaching of Li and Al, followed by a degassing step to precipitate Al, thereby separating these elements effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional leaching methods are used to recover metal elements from waste positive electrodes, then all metal elements (Li, Ni, Co, Mn, Al) can be leached, but the number of subsequent separation steps increases
Solution Approach 1:
The invention extracts and removes aluminum from the leaching system by forming aluminum carbonate precipitate through controlled addition of carbonate solution. This selective extraction allows aluminum to be separated from the leaching solution, reducing the number of separation steps needed for other metal elements while maintaining efficient recovery of all metals.
Solution Approach 2:
The invention changes the chemical parameters of the leaching solution by adjusting pH and adding carbonate ions. This parameter change causes selective precipitation of aluminum as aluminum carbonate, separating it from other metal elements that remain in solution. This approach simplifies the overall separation process by creating distinct phases for different metals.
2Productivity
If acid leaching is used to recover lithium and transition metals, then efficient leaching is achieved, but selective separation of Li from transition metals becomes difficult
Solution Approach 1:
The invention introduces carbonate ions as an intermediary substance that selectively reacts with aluminum to form aluminum carbonate precipitate. This intermediary agent enables selective separation of aluminum from the leaching solution without affecting the dissolution of other metal elements, thereby maintaining high leaching efficiency while achieving precise selective separation.
Solution Approach 2:
The invention performs preliminary separation of aluminum from the leaching solution before recovering other metal elements. By removing aluminum first through carbonate precipitation, the subsequent recovery processes for lithium and transition metals become simpler and more selective, improving overall separation accuracy without compromising initial leaching efficiency.
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 approach allows for high-selectivity separation of Li and Al, reducing the number of steps required and enabling efficient recovery of these elements while leaving transition metals like Ni, Co, and Mn in the solid phase.
Implementation Method 1
bringing waste of at least a positive electrode containing Li and Al into contact with water under presence of pressurized CO2 to allow Li and Al to leach into the water
Implementation Method 2
a degassing step to precipitate Al, thereby separating these elements effectively
Data Source
AI summary
The present disclosure provides a new method capable of separating Li and Al from waste of at least a positive electrode. A method for recycling a positive electrode material according to the present disclosure includes bringing waste of at least a positive electrode containing Li and Al into contact with water under presence of pressurized CO2 to allow Li and Al to leach into the water.