LiFePO4 Battery Recycling Problems
LiPF6, organic carbonate, copper and other chemical substances contained in LiFePO4 Battery are all included in the National Hazardous Waste List. LiPF6 is highly corrosive and easily decomposes to produce HF when exposed to water; organic solvents and their decomposition and hydrolysis products can cause serious pollution to the atmosphere, water, and soil, and harm the ecosystem; heavy metals such as copper accumulate in the environment and eventually Harm humans themselves through the biological chain; once phosphorus enters lakes and other water bodies, it is very easy to cause eutrophication of the water body. It can be seen that if the discarded lithium iron phosphate battery is not recycled, it will be extremely harmful to the environment and human health.
With the rapid development of LiFePO4 Power Station, the demand for LiFePO4 Battery is also rapidly increasing. A large number of LiFePO4 Battery is scrapped and entering the recycling stage. The recycling market of LiFePO4 Battery has shown explosive growth. Then, the current LiFePO4 Battery recycling exists What are the problems?
1. Immature recycling technology
Existing data indicate that there are two types of recycling treatment for waste LiFePO4 Battery: one is recycling metal, and the other is regenerating LiFePO4 cathode material.
(1) Wet recycling of Lithium and Iron
This type of process is mainly to recover Lithium. Because LiFePO4 does not contain precious metals, the recovery process of lithium cobalt oxide is modified. First disassemble the LiFePO4 Battery to obtain the positive electrode material, crush and sieve to obtain the powder; then add the alkali solution to the powder to dissolve aluminum and aluminum oxides, and filter to obtain a filter residue containing Lithium, Iron, etc.; The filter residue is mixed with sulfuric acid and sulfuric acid The mixed solution of hydrogen peroxide (reducing agent) is leached to obtain the leaching liquid; adding alkali to precipitate ferric hydroxide and filtering to obtain the filtrate; burning the iron hydroxide to obtain iron oxide; finally adjusting the pH value of the leaching solution (5.0 ~ 8.0), and filtering the leaching solution to obtain The filtrate is added with solid sodium carbonate to concentrate and crystallize to obtain lithium carbonate.
(2) Regenerated LiFePO4
The recovery of a single element makes the recovery of LiFePO4 that does not contain precious metals produce relatively low economic benefits. Therefore, the solid-phase method is mainly used to regenerate lithium iron phosphate to treat waste LiFePO4 Battery. This process has a high recovery efficiency and a high comprehensive utilization rate of resources.
First disassemble the LiFePO4 Battery to obtain the positive electrode material, crush and sieve to obtain the powder; then heat treatment to remove the residual graphite and binder, and then add the alkaline solution to the powder to dissolve aluminum and aluminum oxide; filter to obtain lithium Analyze the molar ratio of iron, lithium, and phosphorus in the filter residue, add iron source, lithium source and phosphorus source, adjust the molar ratio of iron, lithium, and phosphorus to 1:1:1; add carbon source, after ball milling Calcined in an inert atmosphere to obtain a new lithium iron phosphate cathode material.
2. Imperfect recycling system
Although enterprises in various countries have vigorously promoted LiFePO4 Battery, because it is still in the stage of equipping a large number of vehicles, recycling is still in its infancy, the existing recycling system is not sound, and a systematic and professional vehicle power battery recycling system has not yet been established. The existing recycling system has certain problems, and the recycling efficiency is low. This problem is mainly caused by the following aspects:
(1) Low recyclable amount
A large number of used batteries are scattered in the hands of the people, but the people have no place to put them, so they are treated together with the domestic garbage, so that the scrap batteries recovered from individuals are almost zero, and most of the recycled batteries are generated during the production process of the manufacturing company. The number of large-scale power batteries recovered from waste materials or stockpiled materials is even rarer.
(2) The recovery system is not sound
Many countries have not established a system dedicated to recycling batteries, mainly the extensive collection of small workshops. Similar to China, which is a major producer and consumer of lithium-ion batteries, but due to its large population, the per capita battery population is relatively small. For a long time, recycling companies have not recycled individual lithium-ion batteries that have no recycling value.
(3) High barriers to entry
Enterprises who want to engage in the recycling and processing of used batteries must have the national regulations to apply for a hazardous waste business license. However, there are not many companies that can meet the qualifications for large-scale recycling. Instead, there are a large number of small-scale and low-tech companies, resulting in batteries. Problems that cannot be collected collectively.
(4) High recovery cost
A large number of LiFePO4 materials are used in electric vehicles or LiFePO4 Power Stations. The demand is far greater than that of ordinary small batteries. Recycling them has high social value, but the recycling cost is relatively high. The LiFePO4 Battery does not contain precious metals, which is economical. The value is low.
(5) Weak recycling awareness
For a long time, there has been little publicity and education on the recycling of used batteries in various countries, resulting in a lack of in-depth understanding of the pollution hazards of used batteries and a lack of awareness of conscious recycling.
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