A method for leaching lithium, nickel, cobalt and manganese from the positive electrode of waste NCM type lithium ion batteries

Abstract

The present invention relates to a method for leaching lithium, nickel, cobalt and manganese from the positive electrode of waste NCM-type lithium-ion batteries, belonging to the technical field of waste lithium-ion battery recycling. The present invention comprises dissolving tetraethylammonium chloride and ascorbic acid in deionized water, stirring at a temperature of 30 to 90°C until a colorless and transparent liquid is formed to obtain a deep eutectic solvent, wherein the deep eutectic solvent has a water content of 30 to 60 wt.%. The waste NCM-type lithium-ion battery positive electrode is added to the deep eutectic solvent, and stirred and leached at a temperature of 30 to 90°C to obtain a lithium, nickel, cobalt and manganese leachate. The present invention utilizes the deep eutectic solvent to leach lithium, nickel, cobalt and manganese from the positive electrode of waste NCM-type lithium-ion batteries, and the leaching rate of lithium, nickel, cobalt and manganese is as high as over 99%.

Description

Technical Field

[0001] The invention relates to a method for leaching lithium, nickel, cobalt and manganese from a positive electrode of a waste NCM type lithium ion battery, belonging to the field of waste lithium ion battery recycling. Background Art

[0002] Currently, the recycling of lithium-ion cathode materials is mainly based on traditional pyrometallurgy and hydrometallurgy, which involves a large amount of energy consumption or the use of strong acids and alkalis, causing environmental pollution. In view of this situation, in recent years, many scholars have studied the use of biodegradable organic acids to leaching and recover lithium-ion cathode materials. For example, some scholars have used oxalic acid, citric acid, succinic acid, etc. to leach cathode materials. However, due to the weak acidity of organic acids, they often require long reaction times at higher temperatures, and the leaching rate is often low. Summary of the Invention

[0003] In view of the problems of low leaching efficiency and high requirements for leaching conditions in the current leaching of lithium, nickel, cobalt and manganese from lithium-ion positive electrode materials, the present invention provides a method for leaching lithium, nickel, cobalt and manganese from waste NCM lithium-ion battery positive electrodes, that is, using a deep eutectic solvent to leach lithium, nickel, cobalt and manganese in the waste NCM lithium-ion battery positive electrodes, and the leaching rate of lithium, nickel, cobalt and manganese is as high as over 99%.

[0004] A method for leaching lithium, nickel, cobalt and manganese from the positive electrode of waste NCM type lithium ion batteries, comprising the following steps:

[0005] (1) Tetraethylammonium chloride and ascorbic acid are dissolved in deionized water and stirred at a temperature of 30 to 90° C. until a colorless transparent liquid is formed to obtain a deep eutectic solvent, wherein the water content of the deep eutectic solvent is 30 to 60 wt.%;

[0006] (2) Add the waste NCM lithium-ion battery positive electrode into a deep eutectic solvent and stir and leach at a temperature of 30 to 90°C to obtain a lithium nickel cobalt manganese leachate.

[0007] In the step (1), the molar ratio of tetraethylammonium chloride to ascorbic acid is 3:1 to 1:5.

[0008] In the step (2), the solid-liquid ratio of the waste NCM lithium-ion battery positive electrode to the deep eutectic solvent is g:mL 1:50-200.

[0009] Calculation formula for the leaching rate of lithium, nickel, cobalt and manganese in the positive electrode of waste NCM lithium-ion batteries

[0010] Where X represents the leaching rate, C i (g / L) represents the concentration of metal ion "i" in the leachate, V represents the volume of the leachate, M i (g) and Wi represent the mass of raw materials and the mass percentage of metal i in the raw materials, respectively.

[0011] The principle of using deep eutectic solvent to leaching lithium, nickel, cobalt and manganese from the positive electrode of waste NCM lithium-ion batteries is mainly divided into three steps: (1) ascorbic acid releases protons and combines with oxygen in the positive electrode material, destroying the layered structure of the positive electrode material, generating water and releasing metal ions; (2) +3-valent cobalt and +4-valent manganese are reduced to +2-valent; (3) +2-valent nickel, cobalt and manganese form metal complexes with chloride anions.

[0012] The beneficial effects of the present invention are:

[0013] (1) The present invention utilizes a deep eutectic solvent to leach lithium, nickel, cobalt, and manganese from the positive electrode of waste NCM lithium-ion batteries, thereby avoiding the use of inorganic strong acids / strong bases and reducing agents in traditional wet recovery. The entire leaching process is easy to operate, has a short process and time, and has high leaching efficiency. In addition, tetraethylammonium chloride and ascorbic acid are non-toxic and can be naturally degraded.

[0014] (2) The present invention utilizes deep eutectic solvent to leach lithium, nickel, cobalt and manganese from the positive electrode of waste NCM lithium-ion batteries, which not only improves the shortcomings of wet recovery technology and pyrometallurgical recovery technology in recovering lithium valuable metals, but also achieves a leaching rate of lithium, nickel, cobalt and manganese of more than 99%. DETAILED DESCRIPTION

[0015] The present invention will be further described in detail below in conjunction with specific embodiments, but the protection scope of the present invention is not limited to the contents described above.

[0016] Example 1: A method for leaching lithium, nickel, cobalt and manganese from the positive electrode of a waste NCM lithium-ion battery, comprising the following steps:

[0017] (1) Tetraethylammonium chloride and ascorbic acid were dissolved in deionized water and stirred at 30° C. until a colorless transparent liquid was formed to obtain a deep eutectic solvent, wherein the molar ratio of tetraethylammonium chloride to ascorbic acid was 2:1, the stirring speed was 400 r / min, and the water content of the deep eutectic solvent was 60 wt.%;

[0018] (2) 1 g of waste NCM type (523 type) lithium ion battery positive electrode was added to a deep eutectic solvent and stirred at a temperature of 60°C to obtain a lithium nickel cobalt manganese leachate; wherein the solid-liquid ratio of the waste NCM type lithium ion battery positive electrode to the deep eutectic solvent was g:mL 1:100, and the stirring speed was 800 r / min;

[0019] The lithium content of the leachate was determined by inductively coupled plasma emission spectrometry, and the calculation formula for the leaching rate of lithium, nickel, cobalt and manganese in the positive electrode of waste NCM lithium-ion batteries was

[0020]

[0021] Where X represents the leaching rate, Ci (g / L) represents the concentration of metal ion "i" in the leachate, V represents the volume of the leachate, Mi (g) and Wi represent the mass of the raw material and the mass percentage of metal i in the raw material, respectively. After leaching is completed, the solution is filtered and no visible residue remains, indicating complete leaching of the cathode material.

[0022] The calculated leaching rates of lithium, nickel, cobalt and manganese are as high as 99.81%.

[0023] Example 2: A method for leaching lithium, nickel, cobalt and manganese from the positive electrode of a waste NCM lithium-ion battery, the specific steps are as follows:

[0024] (1) Tetraethylammonium chloride and ascorbic acid were dissolved in deionized water and stirred at 60° C. until a colorless transparent liquid was formed to obtain a deep eutectic solvent, wherein the molar ratio of tetraethylammonium chloride to ascorbic acid was 3:1, the stirring speed was 500 r / min, and the water content of the deep eutectic solvent was 50 wt.%;

[0025] (2) 3 g of waste NCM type (111 type) lithium ion battery positive electrode was added to a deep eutectic solvent and stirred at a temperature of 70 ° C to obtain a lithium nickel cobalt manganese leachate; wherein the solid-liquid ratio of the waste NCM type lithium ion battery positive electrode to the deep eutectic solvent was g: mL 1:150, and the stirring speed was 600 r / min;

[0026] The lithium content of the leachate was determined by inductively coupled plasma emission spectrometry, and the calculation formula for the leaching rate of lithium, nickel, cobalt and manganese in the positive electrode of waste NCM lithium-ion batteries was

[0027]

[0028] Where X represents the leaching rate, Ci (g / L) represents the concentration of metal ion "i" in the leachate, V represents the volume of the leachate, Mi (g) and Wi represent the mass of the raw material and the mass percentage of metal i in the raw material, respectively. After leaching is completed, the solution is filtered and no visible residue remains, indicating complete leaching of the cathode material.

[0029] The calculated leaching rates of lithium, nickel, cobalt and manganese are as high as 99.94%.

[0030] Example 3: A method for leaching lithium, nickel, cobalt and manganese from the positive electrode of a waste NCM lithium-ion battery, the specific steps are as follows:

[0031] (1) Tetraethylammonium chloride and ascorbic acid were dissolved in deionized water and stirred at 80° C. until a colorless transparent liquid was formed to obtain a deep eutectic solvent, wherein the stirring speed was 600 r / min and the water content of the deep eutectic solvent was 40 wt.%;

[0032] (2) 2 g of waste NCM type (622 type) lithium ion battery positive electrode was added to a deep eutectic solvent and stirred at a temperature of 80 ° C to obtain a lithium nickel cobalt manganese leachate; wherein the molar ratio of tetraethylammonium chloride to ascorbic acid was 1:2, the solid-liquid ratio of the waste NCM type lithium ion battery positive electrode to the deep eutectic solvent was g:mL 1:180, and the stirring speed was 1000 r / min;

[0033] The lithium content of the leachate was determined by inductively coupled plasma emission spectrometry, and the calculation formula for the leaching rate of lithium, nickel, cobalt and manganese in the positive electrode of waste NCM lithium-ion batteries was

[0034]

[0035] Where X represents the leaching rate, Ci (g / L) represents the concentration of metal ion "i" in the leachate, V represents the volume of the leachate, Mi (g) and Wi represent the mass of the raw material and the mass percentage of metal i in the raw material, respectively. After leaching is completed, the solution is filtered and no visible residue remains, indicating complete leaching of the cathode material.

[0036] The calculated leaching rates of lithium, nickel, cobalt and manganese are as high as 99.13%.

[0037] The above describes the specific embodiments of the present invention in detail, but the present invention is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in this field without departing from the scope of the present invention.

Claims

1. A method for leaching lithium, nickel, cobalt and manganese from the positive electrode of waste NCM type lithium ion batteries, characterized in that: The specific steps are as follows: (1) Tetraethylammonium chloride and ascorbic acid are dissolved in deionized water and stirred at a temperature of 30-90°C until a colorless transparent liquid is formed to obtain a deep eutectic solvent, wherein the water content of the deep eutectic solvent is 30-60 wt.%; the molar ratio of tetraethylammonium chloride to ascorbic acid is 3:1-1:5; (2) The waste NCM lithium-ion battery positive electrode is added to the deep eutectic solvent and stirred and leached at a temperature of 30~90℃ to obtain a lithium nickel cobalt manganese leachate.

2. The method for leaching lithium, nickel, cobalt and manganese from the positive electrode of waste NCM type lithium ion batteries according to claim 1, characterized in that: In step (2), the solid-liquid ratio of the waste NCM lithium-ion battery positive electrode to the deep eutectic solvent is 1:50-200 g:mL.

Images