阅读说明：本技术 一种废旧锂电池回收浸出LiHCO3溶液深度除氟的方法 (LiHCO recovered and leached from waste lithium battery3Method for deeply removing fluorine from solution ) 是由 冯炎飞 张旭霞 唐光华 郭泽宇 杨亮 于 2020-12-31 设计创作，主要内容包括：本发明属于锂离子电池回收技术领域,提供一种废旧锂离子电池回收LiHCO-3溶液深度除氟的方法,以LiHCO-3溶液为原液制备电池级碳酸锂。包括以下步骤：A.原料准备；B.碱洗除氟剂；B.通CO-2调控体系pH；D.LiHCO-3溶液除氟；E.除氟剂再生。本发明通过向LiHCO-3溶液加入含铝、钛、锆、氮等元素的除氟剂,并鼓CO-2气体调控反应pH,既能达到深度除氟效果,又能保证LiHCO-3溶液体系不变,同时不会引入新的杂质,满足后续电池级碳酸锂的制备要求,提升了产品品质。(The invention belongs to the technical field of lithium ion battery recovery, and provides a method for recovering LiHCO from waste lithium ion batteries 3 Method for deep defluorination of solutions with LiHCO 3 And preparing battery-grade lithium carbonate by using the solution as a stock solution. The method comprises the following steps: A. preparing raw materials; B. washing with alkali to remove fluorine; B. introducing CO 2 Regulating and controlling the pH value of the system; lihco 3 Removing fluorine from the solution; E. and (4) regenerating the fluorine removal agent. The invention is realized by adding LiHCO 3 Adding fluorine removing agent containing aluminum, titanium, zirconium, nitrogen, etc. into the solution, and bubbling CO 2 The gas regulates and controls the pH of the reaction, not only can achieve the effect of deep fluorine removal, but also can ensure LiHCO 3 The solution system is unchanged, new impurities are not introduced, and the requirement of subsequent battery-grade carbonic acid is metThe preparation requirement of the lithium improves the product quality.)

1. LiHCO recovered and leached from waste lithium battery₃The method for deeply removing fluorine from the solution is characterized by comprising the following steps: the method comprises the following steps:

A. preparing raw materials: LiHCO prepared by carbonizing and presoaking a certain amount of waste battery materials₃Solution according to LiHCO₃Adding 5-20% defluorinating agent (1000 mLLIHCO) into the solution₃Adding 50 g-200 g of defluorinating agent into the solution; the defluorinating agent is a composite material which is prepared by alumina, butyl titanate, zirconium sulfate and nitrogen-containing compounds and is activated by acid;

B. alkali washing fluorine removal agent: mixing and stirring the defluorinating agent and inorganic base according to a certain solid-liquid ratio, and then filtering to obtain the defluorinating agent for eluting chloride or sulfate radicals;

C. adjusting the pH of the system: adding the defluorinating agent obtained in the step B into LiHCO₃In solution, then introducing CO₂Adjusting the pH value of the reaction system to 7-8;

D.LiHCO₃removing fluorine from the solution: blowing gas at room temperature while stirring for reaction, and then performing filter pressing to obtain LiHCO₃Removing fluorine liquid and fluorine-containing slag;

E. and (3) regenerating a fluorine removal agent: and D, adding a sodium hydroxide solution into the fluorine-containing slag obtained in the step D according to a certain solid-to-liquid ratio, reacting at a certain temperature, and after complete reaction, performing filter pressing, washing and filter pressing to obtain a regenerated fluorine removal agent.

2. The method for recovering leached LiHCO from waste lithium batteries according to claim 1₃The method for deeply removing fluorine from the solution is characterized by comprising the following steps: the fluorine removal agent in the step A is a CF-2000 fluorine removal agent produced by Changsha Huasheng new material science and technology Limited liability company.

3. The method for recovering leached LiHCO from waste lithium batteries according to claim 1₃The method for deeply removing fluorine from the solution is characterized by comprising the following steps: the inorganic base in the step B is hydrogen hydroxideThe solid-liquid ratio of sodium is 1: 2-5.

4. The method for recovering leached LiHCO from waste lithium batteries according to claim 1₃The method for deeply removing fluorine from the solution is characterized by comprising the following steps: and D, stirring and reacting for 0.5-1.5 h.

5. The method for recovering leached LiHCO from waste lithium batteries according to claim 1₃The method for deeply removing fluorine from the solution is characterized by comprising the following steps: and E, the mass fraction of the sodium hydroxide solution in the step E is 2-5%, the solid-liquid ratio of the fluorine-containing slag to the sodium hydroxide solution is 1: 3-6, the reaction temperature is 25-50 ℃, and the reaction time is 0.5 h.

Technical Field

The invention relates to the technical field of battery recovery, in particular to a defluorination method for recovering leachate from waste lithium batteries.

Background

The number of lithium ion batteries used has increased in multiples in recent years, with a concomitant increase in the number of rejected batteries. The lithium ion battery contains high value-added metals such as cobalt, nickel, manganese, lithium and the like. If the electrolyte is not recycled, resources are wasted, and substances such as electrolyte contained in the battery easily cause environmental pollution. Therefore, it is necessary to effectively recycle the battery and realize the recycling of resources. In the process of purifying and separating valuable elements in a lithium ion battery, the aluminum foil, the copper foil and battery electrode powder can not be completely separated, and fluorine in electrolyte enters leachate along with leaching, so that the fluorine content in subsequent products is high. In the existing recovery process of waste batteries, after a lithium ion battery is crushed and screened, the obtained battery powder is leached, purified and extracted to recover valuable metals, and the defluorination is mainly carried out at the later stage of the recovery process. Disadvantages of back-end fluorine removal include: (1) in the valuable metal recovery process, the concentration of various ions in the wastewater can be gradually increased, so that the rear-section defluorination effect is poor, the consumption of auxiliary materials is increased, a large amount of salt is carried in defluorination residues, and the residue amount is increased; (2) fluorine in the lithium ion battery enters a solution along with various metals in a leaching process, so that equipment corrosion is accelerated; (3) the fluorine ions and other ions in the solution can form stable compounds, which easily causes pipeline blockage; (4) fluorine enters into the back extraction solution of P-204 in the extraction section, and is continuously enriched and circulated, so that fluorine enters into the product in the extraction process, and the product quality is influenced. Therefore, the above problems can be avoided by performing the defluorination treatment on the battery powder leachate.

The existing mature methods for removing fluorine include chemical precipitation, activated alumina adsorption, ion exchange resin, etc. In the precipitation method, calcium salt is widely used as defluorination reagent and is utilized to generate insoluble CaF₂The defluorination effect is achieved. Roasting and reducing the battery powder, and then carbonizing and leaching to obtain LiHCO₃Solution to ensure LiHCO₃The solution system is unchanged, the introduction of calcium salt impurities is avoided, the influence on the preparation of the battery-grade lithium carbonate is avoided, a small amount of calcium salt is added according to the Ksp constant calculation of calcium fluoride, and the defluorination effect is not ideal. Thus, in LiHCO₃The addition of calcium salt in the solution can only achieve the purpose of rough fluorine removal, but cannot achieve the purpose of deep fluorine removal, and the quality of battery-grade lithium carbonate is influenced. The existing adsorptive fluorine removal agent basically has better fluorine removal effect under acidic condition and poor fluorine removal effect under alkaline condition. Therefore, the existing defluorinating agent is adopted to treat the LiHCO with weak alkalinity₃The solution has poor fluorine removal effect.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a method for deeply removing fluorine from a recovered leaching solution of a waste lithium battery, which can achieve the aim of deeply removing fluorine and does not introduce new pollution factors.

In order to achieve the purpose, the invention discloses a method for recovering and leaching LiHCO from waste lithium batteries₃The method for deeply removing fluorine from the solution specifically comprises the following steps:

A. preparing raw materials: LiHCO prepared by carbonizing and presoaking a certain amount of waste battery materials₃Solution according to LiHCO₃Adding 5-20% defluorinating agent (1000 mLLIHCO) into the solution₃Adding 50 g-200 g of defluorinating agent into the solution; the defluorinating agent is a composite material which is prepared by alumina, butyl titanate, zirconium sulfate and nitrogen-containing compounds and is activated by acid;

B. alkali washing fluorine removal agent: mixing and stirring the defluorinating agent and inorganic base according to a certain solid-liquid ratio, and then filtering to obtain the defluorinating agent for eluting chloride or sulfate radicals;

C. adjusting the pH of the system: adding the defluorinating agent obtained in the step B into LiHCO₃In solution, then introducing CO₂Adjusting the pH value of the reaction system to 7-8;

D.LiHCO₃removing fluorine from the solution: blowing gas at room temperature while stirring for reaction, and then performing filter pressing to obtain LiHCO₃Removing fluorine liquid and fluorine-containing slag;

E. and (3) regenerating a fluorine removal agent: and D, adding a sodium hydroxide solution into the fluorine-containing slag obtained in the step D according to a certain solid-to-liquid ratio, reacting at a certain temperature, and after complete reaction, performing filter pressing, washing and filter pressing to obtain a regenerated fluorine removal agent.

Further, the fluorine removal agent in the step A is a CF-2000 fluorine removal agent produced by Changsha Huasheng New Material science and technology Limited liability company.

Further, the inorganic base in the step B is sodium hydroxide, and the solid-liquid ratio is 1: 2-5.

Further, the stirring reaction time in the step D is 0.5-1.5 h.

And furthermore, the mass fraction of the sodium hydroxide solution in the step E is 2-5%, the solid-liquid ratio of the fluorine-containing slag to the sodium hydroxide solution is 1: 3-6, the reaction temperature is 25-50 ℃, and the reaction time is 0.5 h.

According to the invention, the fluorine removal agent activated by acid is subjected to alkali washing, so that a large amount of chlorine radicals and sulfate radicals in a system can not be introduced in the fluorine removal process to cause LiHCO₃The solution system changes. Titanium in the defluorinating agent provides adsorption activity, alumina provides a matrix, and zirconium sulfate provides dispersibility.

The invention introduces CO in the defluorination stage₂Gas in LiHCO₃Introducing CO into the solution₂Not only can achieve the control of pH in the defluorination stage, but also can avoid LiHCO₃The low-fluorine (less than 0.02 percent) battery grade lithium carbonate can be prepared in one step. If the pH is controlled by directly adding acid, LiHCO will be generated₃Conversion of the system to Li₂SO₄the/LiCl system. And introducing CO₂No new impurity is introduced, and the preparation requirement of the subsequent battery-grade lithium carbonate is met.

The fluorine removal agent in the current market absorbs fluorine under an acidic condition, and performs alkaline defluorination, wherein the lower the pH value is, the better the defluorination effect is; but the pH is regulated by adding acid, and LiHCO is caused₃The solution system changes. The invention not only improves the defluorination efficiency, but also ensures LiHCO₃The solution system is unchanged, a defluorinating agent containing aluminum, titanium, zirconium, nitrogen and other elements is adopted, and CO is introduced in the defluorination stage₂And (3) adjusting the pH value of the reaction system to 7-8 by using gas, thereby realizing the purpose of efficiently removing fluorine in a weak alkaline environment.

Detailed Description

Example 1:

A. preparing raw materials: LiHCO prepared by carbonizing and presoaking 1L of waste battery materials₃Solution, measured as LiHCO, having a fluoride ion content of 110ppm₃Adding a defluorinating agent 15% by volume of the solution, i.e. 1000mLLIHCO₃150g of fluorine removal agent was added to the solution. The fluorine removal agent is a CF-2000 fluorine removal agent produced by Changsha Huasheng new material science and technology Limited liability company.

B. Alkali washing of fluorine removal agent: adding 2% NaOH solution into the defluorinating agent according to the solid-to-liquid ratio of 1:2, mixing, stirring, reacting for 0.5h, and filtering to obtain the defluorinating agent for eluting sulfate radicals or chloride ions.

C. Adjusting the pH of the system: adding the washed defluorinating agent into LiHCO₃Introducing CO into the solution₂The pH of the system was adjusted to 7.25.

D.LiHCO₃Removing fluorine from the solution: stirring for 1h while blowing, and vacuum filtering to obtain fluorine-containing slag and defluorinated LiHCO₃Solution, determination of LiHCO after fluorine removal₃The fluoride ion content of the solution was 3.8 ppm.

E. And (3) regenerating a fluorine removal agent: adding 2% sodium hydroxide solution into fluorine-containing slag according to the solid-to-liquid ratio of 1:3, reacting for 0.5h at room temperature, then carrying out suction filtration, washing with deionized water, and carrying out suction filtration again to obtain the defluorinating agent.

F. And (3) regenerating a fluorine removal agent to remove fluorine: the regenerated fluorine removal agent was repeated the procedures A to D in example 1 for LiHCO having a fluorine ion content of 110ppm₃Defluorination of the solution and determination of LiHCO after such defluorination₃The fluoride ion content of the solution was 4.1 ppm.

Example 2:

A. preparing raw materials: LiHCO prepared by carbonizing and presoaking 1L of waste battery materials₃The solution, measured as LiHCO, had a fluoride ion content of 88.5ppm₃The volume of the solution is added with 10 percent of defluorinating agent, namely 1000mLLIHCO₃100g of fluorine removal agent was added to the solution. The fluorine removal agent is a CF-2000 fluorine removal agent produced by Changsha Huasheng new material science and technology Limited liability company.

B. Alkali washing of fluorine removal agent: adding 2% NaOH solution into the defluorinating agent according to the solid-to-liquid ratio of 1:3, mixing, stirring, reacting for 0.5h, and filtering to obtain the defluorinating agent for eluting sulfate radicals or chloride ions.

C. Adjusting the pH of the system: will washAdding LiHCO into the defluorinating agent after washing₃Introducing CO into the solution₂The system pH was adjusted to 7.32.

D.LiHCO₃Removing fluorine from the solution: stirring for 1h while blowing, and vacuum filtering to obtain fluorine-containing slag and defluorinated LiHCO₃Solution, determination of LiHCO after fluorine removal₃The fluoride ion content of the solution was 5.86 ppm.

E. And (3) regenerating a fluorine removal agent: adding 2% sodium hydroxide solution into fluorine-containing slag according to the solid-to-liquid ratio of 1:3, reacting for 0.5h at room temperature, then carrying out suction filtration, washing with deionized water, and carrying out suction filtration again to obtain the defluorinating agent.

F. And (3) regenerating a fluorine removal agent to remove fluorine: the regenerated fluorine-removing agent was used to repeat the procedures A to D in example 2 for LiHCO having a fluorine ion content of 88.5ppm₃Defluorination of the solution and determination of LiHCO after such defluorination₃The fluoride ion content of the solution was 5.75 ppm.

Example 3:

A. preparing raw materials: LiHCO prepared by carbonizing and presoaking 1L of waste battery materials₃The solution, measured as LiHCO, had a fluoride ion content of 88.5ppm₃Adding 5% defluorinating agent, i.e. 1000mLLIHCO, to the volume of the solution₃50g of fluorine-removing agent was added to the solution. The fluorine removal agent is a CF-2000 fluorine removal agent produced by Changsha Huasheng new material science and technology Limited liability company.

B. Alkali washing of fluorine removal agent: adding 2% NaOH solution into the defluorinating agent according to the solid-to-liquid ratio of 1:4, mixing, stirring, reacting for 0.5h, and filtering to obtain the defluorinating agent for eluting sulfate radicals or chloride ions.

C. Adjusting the pH of the system: adding the washed defluorinating agent into LiHCO₃Introducing CO into the solution₂The system pH was adjusted to 7.62.

D.LiHCO₃Removing fluorine from the solution: stirring for 1h while blowing, and vacuum filtering to obtain fluorine-containing slag and defluorinated LiHCO₃Solution, determination of LiHCO after fluorine removal₃The fluoride ion content of the solution was 3.23 ppm.

E. And (3) regenerating a fluorine removal agent: adding 2% sodium hydroxide solution into fluorine-containing slag according to the solid-to-liquid ratio of 1:3, reacting for 0.5h at room temperature, then carrying out suction filtration, washing with deionized water, and carrying out suction filtration again to obtain the defluorinating agent.

F. And (3) regenerating a fluorine removal agent to remove fluorine: the regenerated defluorinating agent was repeated as in example 3Steps A-D for LiHCO having a fluoride ion content of 88.5ppm₃Defluorination of the solution and determination of LiHCO after such defluorination₃The fluoride ion content of the solution was 3.75 ppm.