In the production of new energy materials such as iron phosphate and lithium iron phosphate (LFP), flue gas treatment in the two core processes of drying and calcination has long been a major environmental challenge.
Unlike ordinary industrial exhaust gases, kiln tail gases in lithium battery production are characterized by four critical features: high corrosivity, high temperature, high viscosity, and high-value dust. These include P₂O₅ crystallization causing pipeline blockages, HF strong acid corrosion, ultra-fine powders easily clogging filter bags, and filter media damage under high-temperature conditions.
Traditional glass fiber filter bags and PTFE-coated filter bags frequently suffer from issues such as breakage, dust leakage, surging resistance, frequent replacements, and low recovery rates of valuable powders. These problems not only result in high O&M costs but also easily lead to particulate matter exceeding standards and failure in environmental compliance acceptance.
Currently, leading mass-production lines in the lithium battery industry have comprehensively upgraded their core dust removal components to industrial sintered metal filter bags.
Targeting the specific working conditions of iron phosphate drying and LFP calcination, metal filter bags can be customized with appropriate materials based on actual parameters such as flue gas temperature, corrosion concentration, and dust characteristics. They have become an essential core equipment in the pretreatment of lithium battery tail gases, thoroughly resolving the shortcomings of traditional filter media.
Pain Points in Flue Gas Treatment for Two Major Lithium Battery Processes:
1. Pain Points in Iron Phosphate Drying Tail Gas
In the spray drying and flash drying processes of iron phosphate, the flue gas temperature ranges from 100–280°C, with high humidity and moisture content. The gas carries ultra-fine, sticky iron phosphate powder along with trace amounts of ammonia mist and phosphoric acid mist.
The drawbacks of traditional filter bags are prominent: moist dust causes bag clogging, cleaning is difficult, operating resistance is high, and frequent shutdowns for bag replacement lead to significant losses in the recovery of valuable powders.
2. Pain Points in LFP Calcination Tail Gas
The high-temperature sintering processes in rotary kilns and pusher plate kilns present even harsher conditions: temperatures of 250–600°C, containing corrosive components such as HF, phosphorus oxides, CO, and VOCs.
The most fatal issue is that gaseous P₂O₅ easily crystallizes and blocks pipelines upon temperature fluctuations. Fluorides strongly corrode ordinary filter media. Traditional filter bags lack sufficient high-temperature and anti-corrosion resistance, making them highly susceptible to burning, breakage, and dust leakage, which directly affects the stable operation of downstream incineration and washing systems.
Technical Advantages of Metal Filter Media in Flue Gas Treatment:
Sintered metal filter media are perfectly suited for the high-temperature, highly corrosive, and high-precision dust removal conditions in lithium battery production. They can be flexibly selected based on on-site flue gas temperature, corrosive medium concentration, and dust characteristics. Compared to traditional filter media, they offer significant comprehensive application advantages, effectively solving various pain points in lithium battery tail gas treatment.
Advantage 1: Ultra-Wide Temperature Resistance, Unfazed by High-Temperature Calcination Impacts
Under working conditions, metal filter bags can continuously withstand temperatures up to 450°C, with instantaneous resistance exceeding 500°C, fully covering the 250–400°C regular operating range of calcination kiln tail gases. For ultra-high-temperature special conditions, upgraded high-grade metal materials can be selected to further increase the temperature limit.
This completely eliminates the high-temperature aging, burning, and deformation issues of traditional PTFE and glass fiber filter bags. There is no need to worry about filter bag failure due to kiln temperature fluctuations, ensuring 24-hour continuous and stable system operation, perfectly matching the needs of continuous mass production.
Advantage 2: Fluorine and Phosphorus Corrosion Resistance, Tailored for Special Lithium Battery Flue Gases
HF and phosphorus compounds in LFP calcination tail gases are the "nemesis" of ordinary organic filter media, causing embrittlement and a drastic drop in air permeability during long-term operation.
Customized metal filter media in
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