Lithium Iron Phosphate Precursor Recovery With Low-Impurity Precipitation
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Solution Overview
Problem
Existing methods for reclaiming lithium iron phosphate batteries are inefficient, resulting in high impurity content, high reclamation costs, and significant environmental pollution.
Innovation Solution
A method is developed to produce a lithium iron phosphate precursor using a retired lithium iron phosphate battery as a raw material, involving steps such as soaking the battery cell in acid, performing electrolysis to reclaim copper, oxidizing ferrous iron, precipitating iron phosphate, and precipitating lithium carbonate, thereby achieving low impurity content and reduced reclamation costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If physical methods (screening, flotation, wind separation, eddy-current separation) are used to remove copper and aluminum impurities, then separation capability is improved, but device complexity and maintenance costs increase significantly
Solution Approach 1:
The patent replaces complex mechanical separation systems (screening, flotation, wind separation, eddy-current separation) with a simple chemical precipitation system. Instead of using multiple sophisticated physical separation devices, the invention uses chemical reagents to transform impurities into precipitates that can be removed through simple filtration, thereby reducing device complexity while maintaining impurity removal capability.
Solution Approach 2:
The patent changes the chemical state of impurities from dissolved ions to solid precipitates by adjusting solution parameters (adding precipitating agents). This parameter change allows impurities to be removed through simple filtration rather than complex physical separation processes, reducing equipment requirements while maintaining separation effectiveness.
2Manufacturing precision
If chemical precipitation methods are used to remove copper and aluminum impurities, then impurity removal capability is improved, but material costs and process complexity increase
Solution Approach 1:
The patent extracts and removes only the necessary precipitating agents (sodium hydroxide and sodium carbonate) from the complex chemical process system. By selectively removing impurities through targeted precipitation reactions rather than using multiple chemical treatments, the process is simplified while maintaining effective impurity removal capability.
Solution Approach 2:
The patent discards the need for complex chemical processing steps by using a two-stage precipitation method that naturally separates impurities from the product. The first stage removes copper and aluminum as hydroxide precipitates, and the second stage removes lithium as carbonate precipitate, with the iron phosphate product being recovered in between, simplifying the overall manufacturing process.
3Manufacturing precision
If multi-stage filtering and many operation steps are used to remove impurities, then impurity removal capability is improved, but operation complexity and time consumption increase
Solution Approach 1:
The patent merges multiple impurity removal operations into a unified two-stage precipitation process. Instead of performing separate screening, flotation, wind separation, and eddy-current separation operations followed by multiple filtrations, the invention combines all impurity removal into two chemical precipitation steps followed by a single filtration operation, significantly reducing process time and operational complexity.
4Manufacturing precision
If produced copper(II) sulfide, copper hydroxide, and aluminum hydroxide require further smelting, then impurity removal capability is improved, but process complexity and material consumption increase
Solution Approach 1:
The patent converts the harmful dissolved copper and aluminum ions into beneficial solid precipitates that can be easily filtered and discarded. By using chemical precipitation to transform impurities from a problematic dissolved state into easily removable solid form, the process eliminates the need for complex smelting operations while maintaining effective impurity removal.
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
The method achieves a lithium iron phosphate precursor with low impurity content, reducing reclamation costs and environmental impact, and enables the production of lithium iron phosphate materials with high capacity and good cycle performance for use in lithium battery systems.
Implementation Method 1
soaking the battery cell in acid, and performing filtering
Implementation Method 2
performing electrolysis to reclaim copper: adding a copper cathode and a carbon anode into filtered solution, and performing electrolysis
Implementation Method 3
oxidizing ferrous iron: adding oxidant into the electrolyzed solution, and performing oxidation reaction
Implementation Method 4
precipitating iron phosphate: gradually adjusting pH of the solution resulting from the oxidation reaction to greater than 14 to obtain an iron phosphate precipitate
Implementation Method 5
precipitating lithium carbonate: keeping adding carbonate solution into the post-reaction solution until a white precipitate no longer increases
Data Source
AI summary
A method for producing a lithium iron phosphate precursor by using a retired lithium iron phosphate battery as a raw material is provided, which includes steps of: soaking a battery cell in acid, performing electrolysis to reclaim copper, oxidizing ferrous iron, precipitating iron phosphate, and precipitating lithium carbonate. After precipitation is completed, performing one-step reclaim to obtain the lithium iron phosphate precursor.