Black Mass Impurity Partitioning for High-Purity Cathode Recovery
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Solution Overview
Problem
Existing lithium-ion battery recycling methods face challenges in efficiently removing impurities while preserving the desired metals, often leading to premature loss of metals and decreased recycling throughput due to single-step impurity removal and physical separation processes.
Innovation Solution
A method involving multiple aqueous solution treatments and selective solid-liquid separations is employed to partition impurities into distinct groups, utilizing pH adjustments, chromatography, and chemical reactions to isolate and precipitate cathode active material precursors with high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single-step impurity removal method is used, then the process is simple, but it causes premature loss of metals of interest and cannot achieve high purity
Solution Approach 1:
The impurity removal process is divided into multiple sequential steps: first removing aluminum and calcium ions, then iron ions, and finally magnesium and manganese ions. Each step targets specific impurity groups with selective reagents and pH conditions, allowing progressive purification without premature metal loss.
Solution Approach 2:
The process performs preliminary removal of aluminum and calcium ions before the main leaching step. This preliminary action prevents these impurities from interfering with subsequent metal recovery operations, ensuring high purity of the final cathode active material precursors.
2Manufacturing precision
If physical separation of impurities is performed before leaching, then impurity removal efficiency improves, but recycling throughput decreases due to additional steps
Solution Approach 1:
The patent combines impurity removal operations with the leaching process itself. Impurities are removed during and after leaching through controlled precipitation steps, eliminating the need for separate pre-separation operations and maintaining high recycling throughput.
Solution Approach 2:
The process uses pH adjustment as a key parameter to control impurity removal. By changing pH conditions at different stages, specific impurities are selectively precipitated and removed without requiring physical separation equipment or additional processing steps.
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 effectively separates and removes impurities, maintaining high purity of cathode active material precursors, reducing the need for additional reagents and steps, and enhancing recycling efficiency.
Implementation Method 1
mixing a delithiated black mass and a first aqueous solution to form a pre-leached delithiated black mass and a pre-leach solution, the pre-leach solution comprising a first group of impurity ions from the delithiated black mass
Implementation Method 2
a pre-cathode active material salt may be precipitated from the solution having a purity level demanded for use in synthesizing new cathode active materials
Data Source
AI summary
Methods are provided for removing impurities from recycled battery black mass. The method includes mixing a delithiated black mass with a first solution to form a pre-leached delithiated black mass and a pre-leach solution, separating the pre-leached delithiated black mass from the pre-leach solution, mixing the separated pre-leached delithiated black mass and a second aqueous solution to form a mixture comprising graphite and a leachate solution, and separating the graphite and the leachate solution. The pre-leach solution is comprised of a first group of impurity ions while the leachate solution is comprised of a second group of impurity ions and cathode metal ions.