CN-122000514-A - Recovery and separation method for graphite and valuable metals in waste battery

CN122000514ACN 122000514 ACN122000514 ACN 122000514ACN-122000514-A

Abstract

The application relates to the technical field of recovery of graphite and valuable metals in waste batteries, in particular to a recovery and separation method of graphite and valuable metals in waste batteries, which aims to realize high-efficiency, high-purity and low-cost recovery of graphite and valuable metals and improve the recycling and effective utilization of waste batteries. A method for recovering and separating graphite and valuable metals from waste batteries includes such steps as mixing plastics with graphite to be recovered, immersing the mixture in oxidant solution and alkaline solution, pyrolyzing the immersed mixture, washing the pyrolyzed product with water, introducing carbon dioxide to alkaline aqueous solution to obtain lithium carbonate, acid leaching the oil phase solution and the pyrolyzed product of graphite, regulating pH value of acidic aqueous solution, extracting, back extracting and evaporating to crystallize cobalt salt and nickel salt, and sintering oil phase graphite.

Inventors

JIANG SHUANGSHUANG
LIU PENG
WANG LEI
GENG WENJIE
Wan Shimao
SUN YONGXU
Geng Ruisen
MA TENG

Assignees

万华化学集团股份有限公司

Dates

Publication Date: 20260508
Application Date: 20241107

Claims (10)

1. A method for recovering and separating graphite and valuable metals in waste batteries is characterized by comprising the following steps: Providing plastic and graphite material to be recovered, wherein the graphite material to be recovered comprises graphite, an organic binder and valuable metals; mixing the plastic with the graphite material to be recovered to obtain a mixture; Sequentially soaking the mixture by adopting an oxidant solution and an alkaline solution to oxidize the plastic and dissolve valuable metals in the graphite material to be recovered; pyrolyzing the soaked mixture, and pyrolyzing the oxidized plastic into an oily solvent; Washing and separating the pyrolyzed product to obtain an alkaline aqueous phase solution, an oil phase solution and a graphite pyrolyzed product respectively; introducing carbon dioxide into the alkaline aqueous phase solution to prepare lithium carbonate; Carrying out acid leaching treatment on the oil phase solution and the graphite pyrolysis product, and obtaining an acidic aqueous phase solution and oil phase graphite after phase separation; Adjusting the pH value of the acidic aqueous phase solution, and removing other valuable metal ions except nickel and cobalt in the acidic aqueous phase solution to obtain a first aqueous phase solution of cobalt salt and nickel salt; Sequentially extracting and back-extracting cobalt salt and nickel salt in the first aqueous phase solution by adopting phosphonic acid extractant and sulfuric acid, and evaporating and crystallizing the second aqueous phase solution obtained after back-extraction to obtain cobalt sulfate and nickel sulfate; And sintering the oil phase graphite in a protective atmosphere to prepare the carbon-coated graphite material.
2. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein said plastic satisfies at least one of the following conditions: (1) The plastic is waste plastic; (2) The granularity of the plastic is 100-500 meshes; (3) The plastic comprises at least one of polyethylene, polypropylene, polycarbonate, polyethylene terephthalate and polymethyl methacrylate; (4) The mass ratio of the plastic in the mixture is 0.5% -5%.
3. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein said oxidizer solution satisfies at least one of the following conditions: (1) The oxidant in the oxidant solution comprises at least one of sodium persulfate, hydrogen peroxide and sodium perchlorate; (2) The mass concentration of the oxidant solution is 5% -30%; (3) The soaking temperature of the oxidant solution is 20-30 ℃ and the time is 15 min-60 min.
4. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein said alkaline solution satisfies at least one of the following conditions: (1) The alkali in the alkaline solution comprises at least one of sodium carbonate, potassium carbonate, sodium hydroxide and potassium hydroxide; (2) The concentration of the alkaline solution is 1 mol/L-3 mol/L; (3) The mass ratio of the solid to the liquid soaked in the alkaline solution is 1 (2-5); (4) The soaking temperature of the alkaline solution is 30-90 ℃ and the soaking time is 30-120 min.
5. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein, The pyrolysis temperature is 250-350 ℃, the pressure is 5-10 MPa, and the time is 10-30 min.
6. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein, The mass ratio of the water adopted by the water washing to the pyrolyzed product is 1 (10-25).
7. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein, The molar quantity of the introduced carbon dioxide is 5-20 times of the molar quantity of lithium ions in the alkaline aqueous phase solution, and/or, The recovery separation method further comprises the step of heating the alkaline aqueous phase solution after carbon dioxide is introduced to prepare lithium carbonate, wherein the heating temperature is optionally 60-90 ℃ and the time is 30-60 min.
8. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein said acid leaching treatment satisfies at least one of the following conditions: (1) The acid adopted in the acid leaching treatment comprises at least one of sulfuric acid and hydrochloric acid; (2) The mass concentration of the acid solution adopted in the acid leaching treatment is 10% -30%; (3) The liquid-solid mass ratio of the acid leaching treatment is 1 (5-15); (4) The temperature of the acid leaching treatment is 70-90 ℃ and the time is 30-180 min.
9. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein the pH value of the acidic aqueous solution is adjusted to remove other valuable metal ions except nickel and cobalt in the acidic aqueous solution, thereby obtaining a first aqueous solution of cobalt salt and nickel salt, comprising: Adding an alkaline substance into the acidic aqueous phase solution, and adjusting the pH value of the acidic aqueous phase solution to 4.5-5.0 so as to remove other valuable metal ions except nickel and cobalt in the acidic aqueous phase solution in the form of hydroxide precipitation; optionally, the alkaline substance comprises at least one of sodium bicarbonate, sodium carbonate, potassium carbonate, sodium hydroxide and potassium hydroxide.
10. The method for recovering and separating graphite and valuable metals from waste batteries according to claim 1, wherein, The sintering temperature is 600-1000 ℃, the pressure is 30-50 mpa, and the time is 10-40 h.

Description

Recovery and separation method for graphite and valuable metals in waste battery Technical Field The application relates to the technical field of recovery of graphite and valuable metals in waste batteries, in particular to a recovery and separation method of graphite and valuable metals in waste batteries. Background With the development of battery technology and the increasing level of electricity consumption, the demand and yield of batteries are greatly increased, and a great deal of waste batteries are generated. At present, people focus on how to recycle graphite in waste batteries, the graphite material also contains a small amount of valuable metals, in the related art, when valuable metals in graphite materials are recovered, there are problems of low recovery rate, complex process, high cost and the like. Therefore, how to realize high-efficiency, high-purity and low-cost recovery of graphite and valuable metals is a technical problem to be solved urgently. Disclosure of Invention Based on the above, some embodiments of the present application provide a method for recovering and separating graphite and valuable metals from waste batteries, so as to achieve high-efficiency, high-purity and low-cost recovery of graphite and valuable metals, and improve the recycling and effective utilization of waste batteries. In a first aspect, a method for recovering and separating graphite and valuable metals from waste batteries is provided, comprising: providing plastic and graphite material to be recovered, wherein the graphite material to be recovered comprises graphite, an organic binder and valuable metals; Mixing plastic with graphite material to be recovered to obtain a mixture; Sequentially soaking the mixture by adopting an oxidant solution and an alkaline solution to oxidize plastics and dissolve valuable metals in the graphite material to be recovered; pyrolyzing the soaked mixture, and pyrolyzing the oxidized plastic into an oily solvent; Washing and separating the pyrolyzed product to obtain an alkaline aqueous phase solution, an oil phase solution and a graphite pyrolyzed product respectively; introducing carbon dioxide into the alkaline aqueous phase solution to prepare lithium carbonate; Carrying out acid leaching treatment on the oil phase solution and the graphite pyrolysis product, and obtaining an acidic aqueous phase solution and oil phase graphite after phase separation; Adjusting the pH value of the acidic aqueous solution, and removing other valuable metal ions except nickel and cobalt in the acidic aqueous solution to obtain cobalt salt and a first aqueous solution of the nickel salt; Sequentially extracting and back-extracting cobalt salt and nickel salt in the first aqueous phase solution by adopting phosphonic acid extractant and sulfuric acid, and evaporating and crystallizing the second aqueous phase solution obtained after back-extraction to obtain cobalt sulfate and nickel sulfate; And sintering the oil phase graphite under a protective atmosphere to prepare the carbon-coated graphite material. The method is characterized in that plastic is added into a graphite material to be recovered, the characteristic that the plastic can be pyrolyzed to form an oily solvent is utilized, the oily solvent is utilized to dissolve an organic binder in the mixture, the binder can be separated from the graphite material to be recovered, then, the characteristic that an aqueous phase solution and an oil phase solution are not mutually soluble is utilized, lithium salt in the graphite material to be recovered can be dissolved in an alkaline aqueous phase solution, carbon dioxide is introduced into the alkaline aqueous phase solution, lithium ions can be separated out, then, the oil phase solution and a graphite pyrolysis product are subjected to acid leaching treatment, other valuable metal ions except lithium ions in the oil phase solution and the graphite pyrolysis product are dissolved out, the precipitation sequence of the valuable metal ions is different under different pH values, and other valuable metal ions except nickel and cobalt in the acidic aqueous phase solution obtained after the acid leaching treatment can be precipitated, so that the separation of the cobalt salt and the nickel salt is realized, then, the cobalt salt and the nickel salt in the first aqueous phase solution are sequentially extracted and back extracted by utilizing a phosphonic acid extractant and sulfuric acid, the cobalt salt and the nickel sulfate can be obtained, the cobalt salt and the nickel sulfate in the oil phase solution can be recovered, the graphite material can be recovered, the efficiency is improved, the graphite material can be recovered, the graphite material can be sintered, the cost can be improved, the cost is improved, and the graphite material can be recovered, and the cost is high, and the graphite material can be recovered, and the cost can be sintered and the graphite material can be recover