Method for preparing battery grade iron phosphate from waste and old lithium iron phosphate batteries

A lithium iron phosphate battery, lithium iron phosphate technology, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of reducing the economic value of products, affecting the purity of iron phosphate, increasing recovery costs, etc., and reducing lithium recovery. cost, corrosion mitigation, recovery effect

Active Publication Date: 2019-01-11
INST OF RESOURCES UTILIZATION & RARE EARTH DEV GUANGDONG ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

However, the process is carried out at relatively high temperature (leaching temperature is 25-95°C, oxidation temperature is 40-60°C, iron phosphate precipitation temperature is 60-95°C), high energy consumption leads to increased recovery costs, and the requirements for equipment Higher; the ferric phosphate obtained by controlling the pH to 1.5-4 at a temperature of 60-95°C contains a small amount of ferric hydroxide, which decomposes into ferric oxide after calcination, which affects the purity of ferric phosphate and reduces the economical value of the product. value

Method used

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  • Method for preparing battery grade iron phosphate from waste and old lithium iron phosphate batteries
  • Method for preparing battery grade iron phosphate from waste and old lithium iron phosphate batteries
  • Method for preparing battery grade iron phosphate from waste and old lithium iron phosphate batteries

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Embodiment 1

[0048] This embodiment provides a method for preparing battery-grade iron phosphate from waste lithium iron phosphate batteries, which mainly includes the following steps:

[0049] (1) Battery dismantling and separation: Discharge the waste lithium iron phosphate battery to below 2.0V, put it into a crusher for disassembly, and then separate it by vibrating screening and airflow screening to obtain the first lithium iron phosphate powder, Aluminum powder and copper powder;

[0050] (2) Alkaline leaching: put 300 g of the first lithium iron phosphate powder recovered from waste lithium iron phosphate batteries into 1.5 L of sodium hydroxide solution with a concentration of 3 mol / L and stir for 1 hour at a stirring speed of 500 r / min. room temperature (28°C), then filter and wash to obtain the first filter residue and alkali-containing filtrate, and the alkali-containing solution is supplemented with a second preset concentration of alkali and then continue to leach new second l...

Embodiment 2

[0056] This embodiment provides a method for preparing battery-grade iron phosphate from waste lithium iron phosphate batteries, which mainly includes the following steps:

[0057] (1) Battery dismantling and separation: Discharge the waste lithium iron phosphate battery to below 2.0V, put it into a crusher for disassembly, and then separate it by vibrating screening and airflow screening to obtain the first lithium iron phosphate powder, Aluminum powder and copper powder;

[0058] (2) Alkaline leaching: Put 300 g of the first lithium iron phosphate powder recovered from waste lithium iron phosphate batteries into 2.0 L of sodium hydroxide solution with a concentration of 1 mol / L and stir for 3 hours at a stirring speed of 600 r / min. room temperature (32° C.), then filter and wash to obtain the first filter residue and alkali-containing filtrate, and the alkali-containing solution is supplemented with a second preset concentration of alkali and then continue to leach new secon...

Embodiment 3

[0064] (1) Battery dismantling and separation: Discharge the waste lithium iron phosphate battery to below 2.0V, put it into a crusher for disassembly, and then separate it by vibrating screening and airflow screening to obtain the first lithium iron phosphate powder, Aluminum powder and copper powder;

[0065] (2) Alkaline leaching: put 300 g of the first lithium iron phosphate powder recovered from waste lithium iron phosphate batteries into 2.0 L of sodium hydroxide solution with a concentration of 4 mol / L and stir for 0.5 h at a stirring speed of 600 r / min. The temperature is room temperature (31°C), and then filtered and washed to obtain the first filter residue and alkali-containing filtrate. The alkali-containing solution is supplemented with a second preset concentration of alkali and continues to leach new second lithium iron phosphate powder. The first filter residue enters the next step ;

[0066] (3) Acid leaching: the first filter residue obtained in step (2) is ...

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Abstract

The invention discloses a method for preparing battery grade iron phosphate from waste and old lithium iron phosphate batteries and relates to the technical field of battery recovery. The method can prepare anhydrous battery grade iron phosphate by battery disassembly and separation, alkali leaching, acid leaching, oxidation, precipitation and calcination. Through alkali leaching and then acid leaching and precipitation, impurities such as aluminum in lithium iron phosphate can be removed and the purity of iron phosphate can be improved. The alkali leaching solution and the lithium-rich solution can be reused so that a recovery cost is reduced. After repeated acid supply, the lithium-rich solution immerses novel filter wastes so that the concentration of lithium in the solution and the recovery rate of lithium can be increased and the recovery cost of lithium can be reduced. pH at the precipitation end point is low in a range of 1.0-2.5 so that the formation trend of iron hydroxide isreduced. The aging process after the precipitation reaction can improve the purity of iron phosphate and the produced iron phosphate meets the industry standards. The whole process is carried out at alow temperature so that the corrosion of the solution to the equipment is delayed and the energy consumption and recycling cost are reduced.

Description

technical field [0001] The invention relates to the technical field of battery recycling, and in particular to a method for preparing battery-grade iron phosphate from waste lithium iron phosphate batteries. Background technique [0002] Because lithium iron phosphate power batteries have the advantages of long cycle life and good safety performance, they have been widely used in various electric vehicles and energy storage fields in recent years. Especially in recent years, driven by new energy vehicles and energy storage lithium batteries, the sales of lithium iron phosphate have increased significantly. Behind the mass production means that a large number of waste lithium iron phosphate batteries will be produced every year. The new energy automobile industry will still be in a stage of rapid development at present and in the next 3 to 5 years. It is estimated that the amount of scrapped lithium batteries will reach 500,000 tons by 2020, and will reach 1.16 million tons b...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37
CPCC01B25/375C01P2006/80
Inventor 黄玲王英唐仁衡李文超
Owner INST OF RESOURCES UTILIZATION & RARE EARTH DEV GUANGDONG ACAD OF SCI
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