Battery Black Mass Leachate Purification by FePO4 and AlPO4 Precipitation
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Solution Overview
Problem
Current lithium-ion battery recycling technologies face challenges in developing cost-effective and standardized processes due to the varying chemical compositions of batteries from different manufacturers and the environmental and social impacts associated with cobalt mining, leading to inefficiencies in recovering cathode metals like cobalt, nickel, and manganese.
Innovation Solution
A two-step precipitation process is employed, adjusting pH levels between 1.5 to 4 and 2.5 to 6.5, with the addition of crystallization seeds, to efficiently separate iron and aluminum phosphates from the leachate, minimizing co-precipitation of valuable NMC metals and lithium, and allowing for the recovery of these metals in high purity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If conventional acid leaching is used to recover cathode metals, then metal extraction is achieved, but aluminum and iron impurities co-dissolve reducing recovery purity
Solution Approach 1:
The recovery process is segmented into distinct stages: first acid leaching to extract metals, then selective precipitation to separate impurities. This segmentation allows each stage to optimize for its specific function - maximum extraction followed by purification.
Solution Approach 2:
A selective precipitating agent is introduced as an intermediary substance that specifically targets aluminum and iron ions for removal while leaving cathode metals in solution. This mediator enables selective separation without affecting the valuable metals.
2Manufacturing precision
If pH adjustment is used to precipitate impurities, then aluminum and iron removal is achieved, but valuable NMC metals may co-precipitate
Solution Approach 1:
The pH parameter is precisely controlled and adjusted to specific ranges that favor impurity precipitation while maintaining cathode metals in solution. By optimizing pH levels, the process achieves selective separation based on differential solubility characteristics.
Solution Approach 2:
The precipitation conditions are optimized to create local selectivity - the chemical environment is tailored to favor precipitation of aluminum and iron while keeping nickel, manganese, and cobalt in solution. This local optimization of chemical conditions enables selective removal.
3Productivity
If strong acids are used for leaching, then metal extraction efficiency increases, but environmental and safety concerns increase
Solution Approach 1:
The acid concentration and type are optimized to achieve effective leaching at lower, safer concentrations. By adjusting acid parameters, the process maintains high extraction efficiency while reducing environmental hazards and safety risks associated with concentrated strong acids.
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 process effectively removes aluminum and iron, minimizing the co-precipitation of NMC metals and producing a lithium-rich filtrate that is substantially free from copper, iron, and aluminum, facilitating the recovery of NMC metals and lithium with high efficiency and flexibility across varying battery compositions.
Implementation Method 1
adding phosphoric acid (H3PO4) to the leachate from step a), c) adjusting the pH to form iron phosphate (FePO4) and aluminium phosphate (AlPO4), d) precipitating and removing the formed FePO4 and AlPO4
Data Source
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AI summary
A process for removal of aluminium and iron in the recycling of rechargeable batteries comprising providing a leachate from black mass, adding phosphoric acid (H3PO4) to said leachate and adjusting the pH to form iron phosphate (FePO4) and aluminium phosphate (AlPO4), precipitating and removing the formed FePO4 and AlPO4, and forming a filtrate for further recovery of cathode metals, mainly NMC-metals and lithium.