How to recycle lithium iron phosphate batteries after retirement? After their service life, lithium iron phosphate (LFP) batteries can be recycled to recover valuable materials and reduce environmental impact. The recycling process typically includes pre-treatment, dismantling, material separation, and purification. Pre-treatment involves discharging, testing, and sorting the batteries to determine their residual value and recyclability.
Specific Recycling Technologies
1. Pyrometallurgy Recovery Technique
The Pyrometallurgy recovery technique primarily involves mechanical sorting to separate the battery shell, electrodes, and separator. High-temperature incineration is then applied to the electrodes to burn off organic binders, allowing the lithium iron phosphate powder to separate from the aluminum foil. Volatile compounds are condensed and collected after vaporization.
Advantages:
No additional chemical reactions occur.
Shorter process flow.
Disadvantages:
Limited specificity for different types of waste batteries.
High energy consumption.
Organic solvents and other volatile compounds may cause environmental pollution upon combustion, making it suitable as a preliminary stage for metal separation.
2. Hydrometallurgical Recovery Technique
The Hydrometallurgical recovery technique uses aqueous solutions to dissolve metal ions from LFP batteries. This is followed by precipitation, adsorption, or ion exchange to extract the dissolved metal ions as oxides or salts. Sulfuric acid (H₂SO₄), sodium hydroxide (NaOH), and hydrogen peroxide (H₂O₂) are commonly used reagents.
Immersion Process:
Optimization of reaction conditions, including acid or base solution, concentration, reaction time, and liquid-to-solid ratio, facilitates the dissolution of metal elements into ionic form.
Extraction Process:
Suitable extractants, such as ketones, alcohols, and alkyl phosphates, are used to extract lithium and other metals from the solution, ultimately yielding the target metals.
3. Bioleaching Recovery Technique
Bioleaching recovery technology leverages microbial activity to transform useful components into soluble compounds. Selective dissolution is achieved, followed by separation of valuable metals from impurities in the solution. Although this technology has been studied for the recovery of metals from cobalt-based lithium batteries, research on its application to retired LFP batteries is limited.
