Method for removing aluminum from ferrophosphorus slag after lithium extraction of waste lithium iron phosphate and preparation method of battery-grade iron phosphate

A technology of lithium iron phosphate and iron phosphorus slag, applied in chemical instruments and methods, phosphorus compounds, inorganic chemistry, etc., can solve the problems of lengthy recovery process, low product purity, increased cost of impurity removal, etc., and achieve broad application prospects, The effect of high yield, good economic and social benefits

Active Publication Date: 2022-01-04
GUANGDONG GUANGHUA SCI TECH +1
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Problems solved by technology

However, in the existing process, lithium and iron are often leached at the same time, and then precipitated separately to separate the two, but this operation makes the two interact with each other, increases the cost of impurity removal, and the purity of the final product is not high. And the whole recycling process is lengthy, complicated and costly

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  • Method for removing aluminum from ferrophosphorus slag after lithium extraction of waste lithium iron phosphate and preparation method of battery-grade iron phosphate
  • Method for removing aluminum from ferrophosphorus slag after lithium extraction of waste lithium iron phosphate and preparation method of battery-grade iron phosphate

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preparation example Construction

[0064] The present invention also provides a method for preparing battery-grade iron phosphate, comprising the following steps:

[0065] The ferrophosphorus liquid is obtained according to the method for removing aluminum from the ferrophosphorus slag after extracting lithium from the above-mentioned waste lithium iron phosphate;

[0066] The ferrophosphorus liquid is mixed with an oxidizing agent and a pH regulator to generate an oxidation reaction.

[0067] In one embodiment, the oxidizing agent is selected from at least one of hydrogen peroxide, air, ozone or oxygen.

[0068] In one embodiment, the mass ratio of the oxidant to the ferrophosphorus slag after extracting lithium from the waste lithium iron phosphate is (0.3-0.9):1.

[0069] In one embodiment, the pH regulator is at least one selected from ammonia water, ammonium carbonate or ammonium bicarbonate.

[0070] In one embodiment, the parameters of the oxidation reaction include: the reaction temperature is 40°C-10...

Embodiment 1

[0078] Mix 400g of waste lithium iron phosphate with lithium-extracted phosphorus iron slag, 80g of iron powder, 2600g of pure water and 600g of 98% sulfuric acid to make slurry, and react at 80°C for 4.0 hours. After the reaction, Fe-containing 2+ 、Al 3+ 、PO 4 3- Acid slurry A.

[0079] Under the protection of carbon dioxide, 4 g of 2-pyridinecarboxylic acid was added to the slurry A, the reaction temperature was controlled at 100° C., and the reaction time was 2.0 hours. After the reaction was completed, the solid-liquid separation was carried out to obtain the ferrophosphorus solution after aluminum removal.

[0080] Ferrophosphorus solution was mixed with 400g of 30% hydrogen peroxide, adjusted to pH 1.8 with ammonia water, reacted at 100°C for 4 hours, separated from solid and liquid, and washed to obtain battery grade iron phosphate with a yield of 96.6%.

[0081] Carry out XRD test to the ferric phosphate that above-mentioned preparation obtains, obtain figure 1 Sho...

Embodiment 2

[0084] Mix 700g of waste lithium iron phosphate with phosphorus iron slag, 245g of iron powder, 8.4kg of pure water and 1050g of 85% phosphoric acid to make slurry, and react at 65°C for 5.0 hours. After the reaction is over, you can get Fe-containing 2+ 、Al 3+ 、PO 4 3- Acid slurry A.

[0085] Under the protection of nitrogen, 21g of isoquinoline-3-carboxylic acid was added to the slurry A, the reaction temperature was controlled at 80°C, and the reaction time was 3.0 hours. After the reaction, the solid and liquid were separated to obtain the phosphorus iron liquid after aluminum removal.

[0086] Introduce oxygen into the solution at a flow rate of 0.81L / min into the ferrophosphorus solution, and control the oxygen partial pressure of the solution to 1.2MPa through a pressure reducing valve, adjust the pH to 2.0 with ammonium carbonate, react at 60°C for 5 hours, and then separate the solid from the liquid , and washed to obtain battery-grade iron phosphate with a yield o...

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Abstract

The invention relates to a method for removing aluminum from ferrophosphorus slag after lithium extraction of waste lithium iron phosphate and a preparation method of battery-grade iron phosphate. The method for removing aluminum comprises the following steps: mixing ferrophosphorus slag obtained after lithium extraction of waste lithium iron phosphate, elemental iron, acid and water, and carrying out an acid leaching reaction to prepare slurry A; mixing the slurry A with an aluminum removal agent, carrying out an aluminum removal reaction, and then removing solids to obtain aluminum-removed ferrophosphorus liquid; the aluminum removal agent is selected from at least one of picolinic acid compounds, quinolinic acid compounds and isoquinoline-3-formic acid compounds. The organic aluminum removal agent can be complexed with iron and aluminum to form metal organic complex precipitates with different solubility, the solubility difference of iron and aluminum can be effectively amplified, and preferential precipitation of aluminum is ensured so that aluminum impurities are effectively removed, the product purity of iron phosphate is improved, and the high yield of iron phosphate can be ensured. In addition, the method for removing aluminum is easy to operate, low in equipment investment, environmentally friendly, controllable in quality and easy to industrialize.

Description

technical field [0001] The invention relates to the technical field of battery material recycling, in particular to a method for removing aluminum from iron phosphorus slag after extracting lithium from waste lithium iron phosphate and a method for preparing battery grade iron phosphate. Background technique [0002] Because lithium iron phosphate batteries have many advantages such as high specific capacity, stable structure, safe performance, and long service life, they have been widely used in the field of new energy. With the rapid development of new energy vehicles in my country, based on the current life cycle of lithium-ion batteries generally being 3 to 5 years, with the passage of time, the amount of scrapped power batteries in my country will reach 120,000 to 170,000 tons. A large number of decommissioned waste power batteries are in urgent need of recycling. Since lithium iron phosphate batteries are rich in lithium and iron phosphate, from the perspective of reso...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37
CPCC01B25/375C01P2002/72C01P2006/80Y02W30/84
Inventor 李立平黄铿齐谭泽黄司平
Owner GUANGDONG GUANGHUA SCI TECH
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