Popular Science on Wet Process Production Technology for Lithium Iron Phosphate (LFP) Battery Scrap

I. Raw Material Composition

The wet recycling process primarily handles raw materials such as lithium battery scrap cells and pole pieces. After pretreatment, these materials enter the wet comprehensive recycling system for further processing.

II. Production Process Flow

1. Lithium Battery Scrap Pretreatment System

Pretreatment is the first step of the wet recycling process and mainly includes the following stages:

• Saltwater Discharge: The scrap batteries are first discharged in saltwater to ensure safety during subsequent processing.

• Crushing: After discharge, the batteries undergo primary crushing, secondary crushing, and carbonization treatment.

• Sorting: Through processes such as Z-type sorting, drum screening, tertiary crushing, linear screening, quaternary crushing, and disc screening, the positive and negative electrode powders are separated.

• Magnetic Separation + Screening + Air Separation: Further separation removes metal impurities, yielding pure positive and negative electrode powders.

2. Wet Comprehensive Recycling System for Lithium Battery Scrap Powder

The pretreated positive and negative electrode powders enter the wet comprehensive recycling system, with the following specific steps:

• Mixing and Forming: The pretreated powders are mixed with auxiliary materials such as sodium sulfate, calcium sulfate, and calcium hydroxide, and pressed into green bodies.

• Drying and Roasting: The green bodies are roasted at high temperatures of 600–900°C for 1–3 hours, releasing lithium, sodium, and other elements in the form of soluble salts.

• Crushing and Grinding: The roasted green bodies are crushed and ground into fine powder.

• Leaching + Impurity Removal + Purification + Filtration: The fine powder is mixed with an acid solution for leaching, dissolving valuable metals like lithium into the solution. Impurity removal, purification, and filtration processes then yield a purified leachate.

• MVR Evaporation Concentration + Crystallization Removal + Resin Exchange: The leachate undergoes MVR evaporation concentration, crystallization removal, and resin exchange for further lithium purification.

• Lithium Precipitation + Washing + Drying + Crushing and Packaging: Finally, lithium is precipitated, washed, dried, crushed, and packaged to produce high-purity lithium carbonate.

III. Environmental Protection and Safety Requirements

Environmental protection and safety are critical during the wet recycling process. Specific requirements include:

• Wastewater Treatment: Wastewater generated during the recycling process must be collected and treated to ensure pollutant discharge meets national or local standards.

• Solid Waste Treatment: Solid waste generated must be collected, stored, transported, and handed over to qualified units for treatment in accordance with GB 18597 and HJ 2025 requirements.

IV. Detection Methods

To ensure the purity and quality of recycled materials, highly sensitive detection methods are necessary. Common detection methods include:

• ICP-MS: Used to detect impurity elements, ensuring low detection limits and high precision.

• ICP-OES: Used to detect major elements, ensuring LFP (P, Fe) RSD < 0.5% and Li RSD < 1.0%.

Conclusion:

The wet recycling process for LFP batteries not only efficiently recovers valuable metals but also reduces environmental pollution, offering significant economic and environmental benefits. Through steps such as pretreatment, wet comprehensive recycling, and environmental protection measures, resource recycling and sustainable environmental development are achieved.

SMM New Energy Research Team

Cong Wang 021-51666838

Lingying Zhang 021-51666775

Xiaodan Yu 021-20707870

Rui Ma 021-51595780

Ying Xu 021-51666707

Disheng Feng 021-51666714

Yujun Liu 021-20707895

Yanlin Lü 021-20707875

Xianjue Sun 021-51666757

Chensi Lin 021-51666836

Zhicheng Zhou 021-51666711

He Zhang 021-20707850