阅读说明：本技术 一种回收废旧锂电池制作高纯氢氧化物的方法 (Method for preparing high-purity hydroxide by recycling waste lithium batteries ) 是由 张松柏 陈明忠 于 2020-05-14 设计创作，主要内容包括：本发明公开了一种回收废旧锂电池制作高纯氢氧化物的方法,涉及氢氧化物制备技术领域,该方法包括如下步骤：将废旧锂电池粉末溶解过滤洗涤后得到滤液备用；加入氯酸钠粉末,机械搅拌20-30min后调节溶液pH值为3-4.5,得到氢氧化铁胶体；调节溶液pH值为6.5-8.5,得到氢氧化铝胶体；将氢氧化铝胶体放入氢氧化钠溶液中溶解后过滤；浓缩滤液,再调节pH为5-6,静置,抽滤收集氢氧化铝固体。本发明中通过调节混合溶液至pH值为3.5-4.0,能够使氢氧化铁胶体析出量达到最大；通过调节混合溶液至pH为4.0-5.2,能够使氢氧化铝胶体析出量最大；通过对氢氧化铝胶体进行碱溶解和酸沉淀,能够提高氢氧化铝沉淀的纯度。(The invention discloses a method for preparing high-purity hydroxide by recycling waste lithium batteries, which relates to the technical field of hydroxide preparation, and comprises the following steps: dissolving, filtering and washing waste lithium battery powder to obtain filtrate for later use; adding sodium chlorate powder, mechanically stirring for 20-30min, and adjusting the pH value of the solution to 3-4.5 to obtain ferric hydroxide colloid; adjusting the pH value of the solution to 6.5-8.5 to obtain aluminum hydroxide colloid; putting the aluminum hydroxide colloid into a sodium hydroxide solution for dissolving and then filtering; concentrating the filtrate, adjusting pH to 5-6, standing, and vacuum filtering to collect aluminum hydroxide solid. In the invention, the precipitation amount of the ferric hydroxide colloid can be maximized by adjusting the pH value of the mixed solution to 3.5-4.0; the precipitation amount of the aluminum hydroxide colloid can be maximized by adjusting the pH of the mixed solution to 4.0-5.2; the purity of the aluminum hydroxide precipitate can be improved by carrying out alkali dissolution and acid precipitation on the aluminum hydroxide colloid.)

1. The method for preparing the high-purity hydroxide by recycling the waste lithium batteries is characterized by comprising the following steps of:

step one, waste lithium battery powder is placed into a mixed solution of water, concentrated sulfuric acid, hydrogen peroxide and sodium sulfite, the mass ratio of the waste lithium battery powder to the mixed solution is 1:12-15, the waste lithium battery powder and the mixed solution are mechanically stirred uniformly, the temperature is raised to 30-40 ℃, soaking is carried out for 45-50min, mixed solution is obtained, and filtrate and washing liquid are mixed for standby after filtration and washing;

step two, heating the filtrate to 35-40 ℃, adding sodium chlorate powder, mechanically stirring for 20-30min, adding an acetone mixed aqueous solution of ammonia with the mass fraction of 0.3-0.5 percent, the mass fraction of acetone of 25-35 percent and the rest of water until the pH value of the solution is kept at 3.5-4.0 to obtain ferric hydroxide colloid, filtering and washing by adopting ethanol; continuously dropwise adding the acetone mixed aqueous solution of ammonia of water into the filtrate until the pH value of the solution is kept to be 4.0-5.2, standing to obtain aluminum hydroxide colloid, and washing the aluminum hydroxide colloid by adopting ethanol solution;

step three, putting the ferric hydroxide colloid into a drying oven for drying at the drying temperature of 45-55 ℃ until the quality of the ferric hydroxide colloid powder does not change any more, and obtaining ferric hydroxide powder;

step four, putting the washed aluminum hydroxide colloid into a sodium hydroxide solution with the pH value of 11-13, mechanically stirring until the precipitation is not reduced any more, filtering, and finally washing with deionized water;

and step five, mixing the obtained filtrate and washing liquid, concentrating until the mass fraction of water is 25-30%, then adding dilute sulfuric acid to adjust the pH value to 5-6, standing, performing suction filtration to collect aluminum hydroxide solid, washing the aluminum hydroxide solid by using ethanol, putting the washed aluminum hydroxide solid into an oven to be dried for 5-6 hours, wherein the drying temperature is 45-55 ℃, and obtaining aluminum hydroxide solid powder until the weight is not reduced any more.

2. The method for preparing high-purity hydroxide by recycling waste lithium batteries as claimed in claim 1, wherein in the step one, the mass ratio of water, concentrated sulfuric acid, hydrogen peroxide and sodium sulfite is 10-20:1-3:2-5:2-5, and the water, the concentrated sulfuric acid, the hydrogen peroxide and the sodium sulfite are mixed in sequence, namely, the water, the hydrogen peroxide and the sodium sulfite are mixed firstly, mechanically stirred uniformly, then kept stand for 20-30min, and finally the concentrated sulfuric acid is slowly added into the mixed solution.

3. The method for preparing high-purity hydroxide by recycling waste lithium batteries as claimed in claim 1, wherein the waste lithium battery powder in the step one is prepared by crushing unqualified lithium battery roll cores and scrapped lithium batteries to screen out powder with a particle size of 0.1-1mm, and returning the intercepted powder to continuous grinding.

4. The method for preparing the high-purity hydroxide by recycling the waste lithium batteries as claimed in claim 1, wherein the addition amount of the sodium chlorate in the second step is 1-1.5% of the total mass of the mixed solution.

5. The method for preparing high-purity hydroxide by recycling waste lithium batteries as claimed in claim 1, wherein in the first step, deionized water is adopted for washing for 2-3 times.

6. The method for preparing high-purity hydroxide by recycling waste lithium batteries as claimed in claim 1, wherein the concentration temperature in the fourth step is 100-120 ℃, and the pressure is 0.1 Mpa.

7. The method for preparing high-purity hydroxide by recycling waste lithium batteries as claimed in claim 1, wherein the pH value of the sodium hydroxide in the fourth step is 12.5.

8. The method for preparing high-purity hydroxide by recycling waste lithium batteries as claimed in claim 1, wherein in the step two, when ferric hydroxide colloid is precipitated, an acetone mixed aqueous solution of ammonia is added dropwise until the pH value is kept between 3.5 and 4.0; and when the aluminum hydroxide colloid is precipitated, dropwise adding an acetone mixed aqueous solution of ammonia until the pH value is kept between 4.0 and 5.2.

Technical Field

The invention relates to the technical field of hydroxide preparation, in particular to a method for preparing high-purity hydroxide by recycling waste lithium batteries.

Background

The electrode plates and shells of the waste lithium batteries contain lithium elements, phosphorus elements, iron elements and aluminum elements, wherein the lithium elements and the phosphorus elements are main contents, and the recovery process is mature. The iron element and the aluminum element are not mature in the prior recovery process. However, the contents of iron and aluminum elements in electrode plates and shells of waste lithium batteries are high, the two elements are very common metal elements, and compounds and simple substances of the two elements have use values in various industries such as buildings, traffic and the like. In the recovery process of the electrode plates and the shells of the waste lithium batteries, if the waste liquid containing iron elements and aluminum elements is directly discarded, the environment is affected, and waste is generated. Iron elements in the electrode plates and the shells of the waste lithium batteries can be generated into ferric hydroxide through a reasonable recovery process, the ferric hydroxide can be prepared into nano-sized ferric trioxide, and the nano-sized ferric trioxide material has a good ultraviolet absorption function and a good shielding effect. The ferric trioxide can be used as an additive to be added into high-grade paint or coating. Aluminum element in the electrode plates of the waste lithium batteries can generate aluminum hydroxide, and the aluminum hydroxide is a very important raw material for industrial production.

The existing process for recovering iron and aluminum elements in electrode plates and shells of waste lithium batteries also has the defects of low recovery rate of the iron and aluminum elements, impurities in aluminum hydroxide recovered substances and the like, so that a method is needed to be provided for obtaining high-purity hydroxide.

Disclosure of Invention

The invention aims to provide a method for preparing high-purity hydroxide by recycling waste lithium batteries, so as to solve the technical problem.

A method for preparing high-purity hydroxide by recycling waste lithium batteries comprises the following steps:

step one, waste lithium battery powder is placed into a mixed solution of water, concentrated sulfuric acid, hydrogen peroxide and sodium sulfite, the mass ratio of the waste lithium battery powder to the mixed solution is 1:12-15, the waste lithium battery powder and the mixed solution are mechanically stirred uniformly, the temperature is raised to 30-40 ℃, soaking is carried out for 45-50min, mixed solution is obtained, and filtrate and washing liquid are mixed for standby after filtration and washing;

step two, heating the filtrate to 35-40 ℃, adding sodium chlorate powder, mechanically stirring for 20-30min, adding an acetone mixed aqueous solution of ammonia with the mass fraction of 0.3-0.5 percent, the mass fraction of acetone of 25-35 percent and the rest of water until the pH value of the solution is kept at 3.5-4.0 to obtain ferric hydroxide colloid, filtering and washing by adopting ethanol; continuously dropwise adding the acetone mixed aqueous solution of ammonia of water into the filtrate until the pH value of the solution is kept to be 4.0-5.2, standing to obtain aluminum hydroxide colloid, and washing the aluminum hydroxide colloid by adopting ethanol solution;

step three, putting the ferric hydroxide colloid into a drying oven for drying, wherein the drying temperature is 45-55 ℃, and stopping drying until the quality of the ferric hydroxide colloid powder does not change, so as to obtain ferric hydroxide powder;

step four, putting the washed aluminum hydroxide colloid into a sodium hydroxide solution with the pH value of 11-13, mechanically stirring until the precipitation is not reduced any more, filtering, and finally washing with deionized water;

and step five, mixing the obtained filtrate and washing liquid, concentrating until the mass fraction of water is 25-30%, then adding dilute sulfuric acid to adjust the pH value to 5-6, standing, performing suction filtration to collect aluminum hydroxide solid, washing the aluminum hydroxide solid by using ethanol, putting the washed aluminum hydroxide solid into an oven to be dried for 5-6 hours, wherein the drying temperature is 45-55 ℃, and obtaining aluminum hydroxide solid powder until the weight is not reduced any more.

Preferably, in the step one, the mass ratio of the water to the concentrated sulfuric acid to the hydrogen peroxide to the sodium sulfite is 10-20:1-3:2-5:2-5, and the water, the concentrated sulfuric acid, the hydrogen peroxide to the sodium sulfite are mixed in sequence, namely, the water, the hydrogen peroxide to the sodium sulfite are mixed, mechanically stirred uniformly and then kept stand for 20-30min, and finally the concentrated sulfuric acid is slowly added into the mixed solution.

As a preferred scheme, the specific preparation method of the waste lithium battery powder in the first step is that the unqualified lithium battery roll core and the scrapped lithium battery are crushed to screen out powder with the particle size of 0.1-1mm, and the intercepted powder is returned to be continuously ground.

Preferably, the amount of sodium chlorate added in the second step is 1-1.5% of the total mass of the mixed solution.

As a preferable scheme, in the step one, deionized water is adopted for washing for 2-3 times.

Preferably, the concentration temperature in the fourth step is 100-.

Preferably, the pH of the sodium hydroxide in the fourth step is 12.5.

Preferably, when the ferric hydroxide colloid is precipitated in the second step, the acetone mixed aqueous solution of ammonia is dropwise added until the pH value is kept between 3.5 and 4.0; and when the aluminum hydroxide colloid is precipitated, dropwise adding an acetone mixed aqueous solution of ammonia until the pH value is kept between 4.0 and 5.2.

Compared with the prior art, the invention has the beneficial effects that:

according to the invention, divalent iron ions can be oxidized into trivalent iron ions by adding sodium chlorate, and the precipitation amount of ferric hydroxide colloid can be maximized by firstly adjusting the pH value of the mixed solution to 3.5-4.0 by adopting ammonia; the precipitation amount of the aluminum hydroxide colloid can be maximized by adjusting the pH of the mixed solution to 4.0-5.2 by ammonia; by carrying out alkali dissolution and acid precipitation on the aluminum hydroxide colloid, the impurity precipitate which is insoluble in alkali and contained in the aluminum hydroxide precipitate can be removed, and the purity of the aluminum hydroxide precipitate is improved.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.