CN-121971892-A - Selective flocculant and method for separating anode and cathode materials in waste lithium battery black powder

Abstract

The application discloses a selective flocculant and a method for separating anode and cathode materials in waste lithium battery black powder, and relates to the technical field of flocculants. The selective flocculant provided by the application is phosphate group-carboxymethyl double-modified starch; A process for preparing the phosphate-carboxymethyl dual-modified starch includes such steps as dispersing starch and phosphate in the first solution, regulating pH value, first reacting, centrifugal separation, washing, drying, mixing with the second solution, adding sodium hydroxide, activating, adding chloroacetic acid, second reacting, centrifugal separation, washing and drying. According to the application, when the selective flocculant is used for flotation separation, the high-efficiency separation of the positive electrode material and the graphite negative electrode material in the waste lithium battery black powder can be realized.

Inventors

• ZHAO MEI
• LIU TIEFENG
• LIU YUANLONG
• YANG SHAODONG
• JIANG SIHUA
• HONG MIN
• WU JIAWEI
• LI NA

Assignees

• 衢州动力电池和储能研究院

Dates

Publication Date

20260505

Application Date

20260109

Claims (10)

1. 1. A selective flocculant, characterized in that the selective flocculant is phosphate-carboxymethyl double-modified starch; The preparation method of the phosphate-carboxymethyl double-modified starch comprises the following steps: Dispersing starch and phosphate in a first solution, adjusting the pH to be acidic, performing a first reaction at a first temperature, centrifuging, taking a precipitate, cleaning and drying to obtain phosphorylated starch; mixing the phosphorylated starch with a second solution, and adding a solvent containing sodium hydroxide to activate the phosphorylated starch; and adding chloroacetic acid into the activated phosphorylated starch, performing a second reaction at a second temperature, centrifuging, taking a precipitate, and washing and drying to obtain the phosphate-carboxymethyl double-modified starch.
2. 2. A selective flocculant according to claim 1, wherein the mass ratio of starch to phosphate is 10:0.5-2, and/or The first solution is water, and the mass ratio of the mixture of the starch and the phosphate to the water is 1:2-5.
3. 3. The selective flocculant of claim 1 wherein the first temperature is 45 ℃ to 65 ℃ and the first reaction time is 3 hours to 5 hours.
4. 4. The selective flocculant of claim 1 wherein the phosphate salt is one or more of sodium tripolyphosphate, sodium hexametaphosphate, and sodium dihydrogen phosphate.
5. 5. A selective flocculant according to claim 1, wherein the activation temperature is 40 ℃ to 55 ℃, the activation time is 0.5 h to 2h, and/or The second temperature is 40-60 ℃, and the second reaction time is 3-5 h.
6. 6. A selective flocculant according to claim 1 wherein the acid to base ratio of the phosphorylated starch to the sodium hydroxide is 1:1.5 to 2.5, and/or The mass ratio of the phosphorylated starch to the chloroacetic acid is 1:0.3-1.
7. 7. The selective flocculant of claim 1 wherein the second solution is a 75-90% ethanol solution.
8. 8. The method for separating the anode and cathode materials in the waste lithium battery black powder is characterized by comprising the following steps of: regulating pH after mixing the waste lithium battery black powder to obtain pulp with pH of 7-10; adding a flotation reagent into the ore pulp for flotation so as to separate negative electrode materials and positive electrode materials in the waste lithium battery black powder, wherein the flotation reagent comprises the selective flocculant as claimed in any one of claims 1 to 7.
9. 9. The method for separating positive and negative electrode materials in waste lithium battery black powder according to claim 8, wherein the flotation reagent further comprises a collector and a foaming agent; Adding a flotation reagent into the ore pulp for flotation so as to separate a negative electrode material and a positive electrode material in the waste lithium battery black powder, wherein the flotation reagent comprises the following steps: And sequentially adding the selective flocculant, the collector and the foaming agent into the ore pulp, stirring and then scraping bubbles to separate the negative electrode material and the positive electrode material in the waste lithium battery black powder.
10. 10. The method for separating anode and cathode materials in waste lithium battery black powder according to claim 9, wherein the addition amount of the selective flocculant is 500 g/t-1500 g/t.

Description

Selective flocculant and method for separating anode and cathode materials in waste lithium battery black powder Technical Field The application relates to the technical field of flocculating agents, in particular to a selective flocculating agent and a method for separating positive and negative electrode materials in waste lithium battery black powder. Background The problems of low separation efficiency usually exist when the flotation method separates the positive electrode material and the graphite negative electrode material in the positive and negative electrode mixture due to the problems of fine material granularity of the waste lithium battery black powder (namely the positive and negative electrode mixture) and spontaneous hydrophobic flocculation of the fine graphite. Disclosure of Invention The application mainly aims to provide a selective flocculant and a method for separating positive and negative electrode materials in waste lithium battery black powder, and aims to solve the technical problem of low separation efficiency of positive and negative electrode materials of waste lithium batteries in related technologies. In order to achieve the above purpose, the present application provides a selective flocculant, wherein the selective flocculant is phosphate group-carboxymethyl double-modified starch; The preparation method of the phosphate-carboxymethyl double-modified starch comprises the following steps: Dispersing starch and phosphate in a first solution, adjusting the pH to be acidic, performing a first reaction at a first temperature, centrifuging, taking a precipitate, cleaning and drying to obtain phosphorylated starch; mixing the phosphorylated starch with a second solution, and adding a solvent containing sodium hydroxide to activate the phosphorylated starch; and adding chloroacetic acid into the activated phosphorylated starch, performing a second reaction at a second temperature, centrifuging, taking a precipitate, and washing and drying to obtain the phosphate-carboxymethyl double-modified starch. In one embodiment, the mass ratio of the starch to the phosphate is 10:0.5-2, and/or The first solution is water, and the mass ratio of the mixture of the starch and the phosphate to the water is 1:2-5. In one embodiment, the first temperature is 45 ℃ to 65 ℃ and the first reaction time is 3 h to 5h. In one embodiment, the phosphate is one or more of sodium tripolyphosphate, sodium hexametaphosphate, and sodium dihydrogen phosphate. In one embodiment, the activation temperature is 40-55 ℃, the activation time is 0.5-2 hours, and/or The second temperature is 40-60 ℃, and the second reaction time is 3-5 h. In one embodiment, the acid-base ratio of the phosphorylated starch to the sodium hydroxide is 1:1.5-2.5, and/or The mass ratio of the phosphorylated starch to the chloroacetic acid is 1:0.3-1. In one embodiment, the second solution is a 75-90% ethanol solution. In addition, in order to achieve the above purpose, the application also provides a method for separating positive and negative electrode materials in the waste lithium battery black powder, which comprises the following steps: regulating pH after mixing the waste lithium battery black powder to obtain pulp with pH of 7-10; And adding a flotation reagent into the ore pulp for flotation so as to separate the negative electrode material and the positive electrode material in the waste lithium battery black powder, wherein the flotation reagent comprises the selective flocculant. In one embodiment, the flotation reagent further comprises a collector and a frother; Adding a flotation reagent into the ore pulp for flotation so as to separate a negative electrode material and a positive electrode material in the waste lithium battery black powder, wherein the flotation reagent comprises the following steps: And sequentially adding the selective flocculant, the collector and the foaming agent into the ore pulp, stirring and then scraping bubbles to separate the negative electrode material and the positive electrode material in the waste lithium battery black powder. In one embodiment, the addition amount of the selective flocculant is 500 g/t-1500 g/t. One or more technical schemes provided by the application have at least the following technical effects: The application provides a green, low-medicine-consumption and low-cost selective flocculant, which is phosphate group-carboxymethyl double-modified starch, and when the selective flocculant is utilized for flotation separation, the positive electrode material in the waste lithium battery black powder can be selectively flocculated through the synergistic effect of double functional groups of the selective flocculant, so that the high-efficiency separation of the positive electrode material and the graphite negative electrode material in the waste lithium battery black powder is realized. Drawings In order to more clearly illustrate the embodiments of the present application or the t