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Recovery method of waste lithium iron phosphate positive electrode material

A technology for lithium iron phosphate and positive electrode materials, which is applied in the field of recycling waste lithium iron phosphate positive electrode materials, can solve the problems of containing more aluminum scraps, increasing the cost of impurity removal, and backward recycling technology, so as to achieve high lithium content, reduce purification and Wastewater treatment cost, effect of high industrial production value

Active Publication Date: 2021-03-05
BYD CO LTD +1
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Problems solved by technology

[0003] At present, the recovery and regeneration of valuable metal elements in waste batteries is a relatively popular scientific research field. The main recovery methods are: hydrometallurgy, pyrometallurgy and physical restoration. Among them, hydrometallurgy has the characteristics of high element recovery rate and high purity. It is widely used, but the current recycling technology is still relatively backward. The positive and negative electrode powders obtained after physical dismantling of waste batteries often contain more impurities such as aluminum filings and iron filings, which cannot achieve high selectivity. When the lithium element in the lithium positive electrode recycling material is used, strong acids and strong oxidants are often used in element leaching, which will dissolve impurity elements, such as iron, aluminum and phosphate and other soluble metals or oxides in the lithium-containing leach solution, increasing the subsequent The cost of impurity removal, the dissolved and leached phosphate enters the waste liquid, and at the same time, iron and aluminum are easy to form colloidal precipitates to adsorb lithium elements and reduce the recovery rate of lithium elements

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  • Recovery method of waste lithium iron phosphate positive electrode material
  • Recovery method of waste lithium iron phosphate positive electrode material
  • Recovery method of waste lithium iron phosphate positive electrode material

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Embodiment 1

[0064] Separation: ①Treat the crushed lithium iron phosphate-containing pole pieces at 550°C and nitrogen atmosphere for 120 minutes, and then use vibrating sieve and physical separation to separate the current collector from the lithium iron phosphate powder; ②Preparation selectivity Leaching agent A: Add 70g of ammonium sulfate to 320ml of deionized water, then add 25ml of 30wt% hydrogen peroxide solution; and leaching agent B: a mixed solution of 30ml of 3mol / L sulfuric acid solution and 30ml of 30wt% hydrogen peroxide solution③ Put 100g of lithium iron phosphate powder into the prepared leach solution A, and then add the leach agent B dropwise after 5 minutes. The reaction process is greater than 3.0. After stirring for 2 hours, filter to obtain the leach residue and lithium-containing leach solution. The filter cake was washed twice with water to obtain lithium leaching solution. Put the leaching residue into 5% sodium hydroxide aqueous solution, stir and dissolve the al...

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Abstract

The invention provides a recovery method of a waste lithium iron phosphate positive electrode material. The method comprises the following steps: S1, adding waste lithium iron phosphate powder to a leaching agent A, slowly adding a leaching agent B, adjusting the pH value to be more than or equal to 2, and carrying out solid-liquid separation to obtain a lithium-containing leaching agent and a leaching residue; S2, adding a precipitator into the lithium-containing leachate to obtain lithium carbonate; S3, adding a first alkaline solution into the leaching residues, and filtering to obtain an aluminum-containing solution and filter residues; S4, adjusting the pH value of the aluminum-containing solution to obtain an aluminum hydroxide precipitate; S5, adding the filter residue into a firstacidic solution, performing filtering, adding a second alkaline solution into the obtained filtrate, adjusting the pH value to 2.0-2.7 to obtain basic iron phosphate, and adding phosphoric acid to obtain iron phosphate. The leaching agent A comprises a mixed solution of at least one of a weak base solution or a weak acid solution and a first oxidizing agent; and the leaching agent B comprises a mixed solution of a second acidic solution and a second oxidant. By the adoption of the method, the leaching rate of lithium is high, impurities are few, the purification and wastewater treatment cost during lithium carbonate preparation is reduced, and meanwhile iron phosphate can be efficiently recycled.

Description

technical field [0001] The application relates to the field of battery materials, in particular to a method for recycling waste lithium iron phosphate cathode materials. Background technique [0002] Lithium iron phosphate batteries have the advantages of low cost, non-toxicity, high capacity and excellent cycle performance, and are widely used in electric vehicles and energy storage industries; with the vigorous implementation of the national development of new energy policies, metal lithium and other rare The consumption of metals is increasing; at the same time, a large number of power batteries are decommissioning. It is predicted that by 2030, the number of scrapped lithium-ion batteries in the world will reach more than 11 million tons, and the world will face environmental pollution and rare metals together. Therefore, it is extremely important to invent an effective technology for recycling valuable elements in waste batteries. [0003] At present, the recovery and ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01B25/37C01F7/42C01D15/08H01M10/54C01D15/02
CPCC01B25/375H01M10/54C01F7/42C01D15/08C01D15/02Y02W30/84
Inventor 邓金兴徐茶清曹文玉
Owner BYD CO LTD
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