The new energy vehicle industry is developing rapidly. Due to their high safety, long cycle life, and cost advantages, lithium iron phosphate (LiFePO₄) batteries have become the mainstream choice in the power battery market. However, the large-scale retirement of these batteries is becoming a prominent issue. Spent batteries must be handled properly. If neglected, they will waste valuable resources like lithium, iron, and phosphorus. Furthermore, electrolyte leakage and heavy metal dissolution can lead to serious environmental pollution. Therefore, developing efficient, economical, and eco-friendly recycling technologies is now urgent.
Currently, recycling technologies for spent LiFePO₄ cathode materials fall into three main categories: direct regeneration, pyrometallurgy, and hydrometallurgy. The industrial implementation of these processes requires high-efficiency mechanical de-agglomeration equipment at the very front end. Devices like the Turbo Mill are now the key factors determining final recycling purity and efficiency.
Direct Regeneration Technology: Crystal Repair and Mechanical Activation
Direct regeneration technology restores electrochemical performance by repairing structural defects in the material, offering advantages such as short process flow and low carbon emissions.
1. High-Temperature Solid-State Method
The high-temperature solid-state method reconstructs the crystal structure by adding lithium sources under high-temperature conditions. For example, vanadium-doped regenerated materials can achieve a discharge specific capacity of 154.3 mAh/g at 0.1C. However, this method has high energy consumption and extremely strict requirements for raw material particle size uniformity and purity.
2. Hydrothermal Method
The hydrothermal method performs material restoration in lithium-containing solutions. For example, using Na₂SO₃ as a reducing agent, regenerated cathode materials can reach a reversible capacity of 135.9 mAh/g at 1C, with capacity retention of 99% after 100 cycles. However, safety risks associated with high-pressure environments limit its large-scale application.
Pyrometallurgical Technology: High-Temperature Decomposition and Molten Salt Assistance
Pyrometallurgical technology separates metal components through high-temperature roasting of battery materials.
Traditional pyrometallurgy involves calcination at around 1000°C to decompose organic substances and binders, followed by hydrometallurgical processes to recover valuable metals.
To reduce energy consumption, researchers developed molten salt-assisted methods. Using NaOH or NaHSO₄ as activators, the reaction temperature can be reduced to 400–900°C, achieving lithium leaching rates above 99%.
However, pyrometallurgical processes still suffer from high energy consumption, generation of hazardous gases such as HF, and difficulties in salt recycling, which limit their large-scale industrial application under increasingly strict environmental regulations.
Hydrometallurgical Technology: Mainstream Process and the Core Role of Turbo Mill
Hydrometallurgy is currently the most commercially viable recycling technology. Its standard process includes: pretreatment → leaching → impurity removal → product regeneration.
Pretreatment Stage: Turbo Mill Enables Efficient “Al–Fe–Li Separation”
The quality of pretreatment directly determines the purity of the subsequent solution system. In industry, conventional mechanical crushing methods are commonly used. However, traditional crushers (such as shear crushers and hammer crushers) often cause aluminum foil and cathode powder to be “mixed together,” forming embedded contamination. Residual aluminum foil introduces impurities such as Al, F, and Ti, significantly increasing downstream chemical purification difficulty.
Turbo Mill Enhancement in Pretreatment
By introducing the Turbo Mill, a high-efficiency mechanical de-agglomeration device, into the pretreatment line, high-frequency shear forces and vortex impacts are generated inside the grinding chamber through high-speed rotating turbine blades.
Selective delamination:
Aluminum foil is ductile, while spent LFP cathode powder is hard and brittle. Under high-frequency rubbing and micro-impact effects of the Turbo Mill, cathode coating materials are rapidly and precisely detached from the aluminum foil surface (de-coating) and pulverized.
Morphology-based separation:
Aluminum foil is sheared into regular small flakes, while LFP becomes ultrafine powder. Through subsequent air classification or vibrating screening, efficient physical separation of “aluminum flakes” and “lithium iron phosphate powder” can be easily achieved, fundamentally preventing aluminum impurities from entering the leaching system.
Leaching Process: Total Element Leaching and Selective Lithium Extraction
Total element leaching:
Using inorganic or organic acid systems (such as H₃PO₄–oxalic acid system), lithium and iron leaching rates can exceed 97%. However, acid consumption is high and wastewater treatment is burdensome.
Selective lithium extraction:
Using oxidants such as H₂O₂ and NaClO, lithium is preferentially leached (leaching rate >95%), while iron and phosphorus remain in the residue as iron phosphate (FePO₄).
Impurity Removal Challenges: Deep Separation and Crystal Control
Deep removal of Al, F, and Ti remains a major industrial bottleneck.
Fluoride coordination methods can simultaneously remove 99.4% of aluminum and 96.4% of fluorine, but require precise control of Al/F ratio. Thermal treatment can remove over 90% of fluorine but may release toxic gases. Induced crystallization achieves over 80% titanium removal with iron loss below 0.8%.
Product Regeneration Stage
Total leachate can be used to synthesize FePO₄ and Li₂CO₃. However, impurity incorporation affects product purity. Lithium-extracted residues must undergo acid leaching, purification, and precipitation to produce battery-grade FePO₄.
At this stage, powders refined by Turbo Mill exhibit higher reactivity, reducing chemical reagent consumption by 10%–15%.
Emerging Technologies: Mechanical Activation and Electrochemical Methods
In the field of mechanical activation, Turbo Mill demonstrates dual functions of ultrafine grinding and mechanochemical activation.
Ultra-high tip-speed milling does more than just reduce particle size. It also causes lattice distortion, dislocations, and an accumulation of mechanical energy within the material. This mechanically activated LFP powder enables lithium extraction under very mild conditions. It eliminates the need for strong acids or harsh oxidants while achieving up to a 99.55% lithium leaching efficiency. Ultimately, this significantly improves both process economy and environmental performance.
Industry Challenges and Future Prospects
Despite diverse recycling technologies, three major bottlenecks remain:
- Insufficient high-value utilization of iron-phosphorus resources
- Difficulty in deep removal of impurities such as Al and Ti
- Conflict between economic cost and environmental sustainability
Future Pathways Toward a Closed-Loop Industry Chain
Future development should accelerate green and short-process recycling strategies:
- Process upgrade at the source: Promote high-efficiency physical separation equipment such as Turbo Mill to minimize aluminum contamination before hydrometallurgical processing, thereby reducing chemical consumption.
- High-value utilization: Explore deep applications of lithium extraction residues as catalysts or functional materials.
- Material upgrading: Develop direct regeneration routes such as converting spent LiFePO₄ into high-voltage solid-solution LiFe₀.₅Mn₀.₅PO₄.
บทสรุป
Achieving a green closed loop in the new energy vehicle industry chain requires efficient, clean, and high-value battery recycling. Multi-technology synergy is the key breakthrough here. It starts with high-efficiency physical separation and mechanical activation using the Turbo Mill at the front end. It then moves to precise separation in hydrometallurgy, and ends with short-process, high-value regeneration at the back end.
By deeply integrating advanced industrial grinding equipment with chemical recycling technologies, we can establish a closed-loop system of “recycling – regeneration – application.” This will provide strong resource support for the sustainable development of the low-carbon economy.
ขอบคุณที่อ่านนะคะ หวังว่าบทความของฉันจะเป็นประโยชน์นะคะ แสดงความคิดเห็นไว้ด้านล่างได้เลยค่ะ หรือหากมีข้อสงสัยเพิ่มเติม สามารถติดต่อตัวแทนฝ่ายบริการลูกค้าออนไลน์ของ Zelda ได้ค่ะ
— โพสต์โดย เอมิลี่ เฉิน
