阅读说明：本技术 一种氟化锂的制备方法 (Preparation method of lithium fluoride ) 是由 吴凯飞 赵正红 朱大明 朱晶晶 于 2020-05-19 设计创作，主要内容包括：本发明属于化学制备技术领域,尤其涉及一种氟化锂的制备方法。该制备方法包括：将碳酸锂与纯水混合,得到第一溶液；在第一溶液中通入二氧化碳,通入的二氧化碳将所述碳酸锂进行氢化,得到碳酸氢锂溶液；将得到的碳酸氢锂溶液进行过滤；在过滤后的碳酸氢锂溶液中加入表面活性剂,搅拌至表面活性剂完全溶解,得到第二溶液；在第二溶液中加入浓度为40％的氢氟酸,控制加入氢氟酸的第二溶液的pH为4-5,结束反应后,得到氟化锂浆料；将氟化锂浆料进行离心分离,得到氟化锂湿料；将得到的氟化锂湿料进行烘干,得到最终产品。通过本发明获得的氟化锂颗粒的粒径大于120微米,晶体结构规则,流动性显著提高,可满足一些新产品制备对大颗粒氟化锂原料的要求。(The invention belongs to the technical field of chemical preparation, and particularly relates to a preparation method of lithium fluoride. The preparation method comprises the following steps: mixing lithium carbonate with pure water to obtain a first solution; introducing carbon dioxide into the first solution, and hydrogenating the lithium carbonate by the introduced carbon dioxide to obtain a lithium bicarbonate solution; filtering the obtained lithium bicarbonate solution; adding a surfactant into the filtered lithium bicarbonate solution, and stirring until the surfactant is completely dissolved to obtain a second solution; adding 40% hydrofluoric acid into the second solution, controlling the pH of the second solution added with the hydrofluoric acid to be 4-5, and obtaining lithium fluoride slurry after the reaction is finished; performing centrifugal separation on the lithium fluoride slurry to obtain a lithium fluoride wet material; and drying the obtained lithium fluoride wet material to obtain a final product. The particle size of the lithium fluoride particles obtained by the method is larger than 120 microns, the crystal structure is regular, the fluidity is obviously improved, and the requirements of some new product preparations on large-particle lithium fluoride raw materials can be met.)

1. A preparation method of lithium fluoride is characterized by comprising the following steps:

mixing lithium carbonate with pure water to obtain a first solution;

introducing carbon dioxide into the first solution, and hydrogenating the lithium carbonate by the introduced carbon dioxide to obtain a lithium bicarbonate solution;

filtering the obtained lithium bicarbonate solution;

adding a surfactant into the filtered lithium bicarbonate solution, and stirring until the surfactant is completely dissolved to obtain a second solution;

adding 40% hydrofluoric acid into the second solution, controlling the pH of the second solution added with the hydrofluoric acid to be 4-5, and obtaining lithium fluoride slurry after the reaction is finished;

performing centrifugal separation on the lithium fluoride slurry to obtain a lithium fluoride wet material;

and drying the obtained lithium fluoride wet material to obtain a final product.

2. The method of claim 1, wherein the lithium carbonate has a purity of not less than 99.9%.

3. The method for preparing lithium fluoride according to claim 1, wherein the mass ratio of lithium carbonate to pure water in the first solution is 1: 10-30.

4. The method for preparing lithium fluoride according to claim 1, wherein carbon dioxide is introduced into the first solution, and the introduced carbon dioxide hydrogenates the lithium carbonate to obtain a lithium bicarbonate solution, and specifically comprises:

the mass ratio of the lithium carbonate to the introduced carbon dioxide is 1: 1-5, and the introduction time of the carbon dioxide is 1-3 hours.

5. The method for preparing lithium fluoride according to claim 1, wherein the surfactant is added in an amount of 0.01-1% by mass based on the mass of lithium carbonate in the filtered lithium bicarbonate solution.

6. The method for preparing lithium fluoride according to claim 1, wherein the surfactant is one or more of alkyl ammonium salt with 12-16 carbon atoms, fatty alcohol-polyoxyethylene ether with 11-13 carbon atoms and fatty acid-polyethylene glycol ester with 10-24 carbon atoms.

7. The method for preparing lithium fluoride according to claim 1, wherein the mass ratio of the mass of lithium carbonate in the filtered lithium bicarbonate solution to the addition amount of hydrofluoric acid with the concentration of 40% is 1: 1.35-1.5.

8. The method for preparing lithium fluoride according to claim 1, wherein the step of centrifuging the lithium fluoride slurry to obtain a wet lithium fluoride material comprises: the centrifugation is carried out at normal temperature, and the maximum rotation speed of the centrifugation is 1500 revolutions per minute.

9. The method as claimed in claim 1, wherein the obtained lithium fluoride wet material is dried at a temperature of 100-160 ℃.

Technical Field

The invention belongs to the technical field of chemical preparation, and particularly relates to a preparation method of lithium fluoride.

Background

With the development of new energy automobile industry in recent years, the demand of lithium ion batteries is greatly increased, and the demand of lithium fluoride as an indispensable raw material of lithium ion battery materials is also increased more and more.

At present, the most common method for industrially producing lithium fluoride is to synthesize lithium fluoride by adding hydrofluoric acid into lithium carbonate, and the method has the advantages of simple process, high operability, low requirement on equipment and high economical efficiency. However, the lithium fluoride produced by the method has small particle size and irregular crystal structure, so that the product has poor fluidity and is difficult to meet the requirement of some new product preparation on large-particle lithium fluoride raw materials.

Disclosure of Invention

Aiming at the defects in the prior art, the invention provides a preparation method of lithium fluoride, which aims to solve the technical problems of small particle size and irregular crystal structure of the lithium fluoride prepared by the prior art.

The technical scheme of the invention is as follows:

a preparation method of lithium fluoride is characterized by comprising the following steps:

mixing lithium carbonate with pure water to obtain a first solution;

introducing carbon dioxide into the first solution, and hydrogenating the lithium carbonate by the introduced carbon dioxide to obtain a lithium bicarbonate solution;

filtering the obtained lithium bicarbonate solution;

adding a surfactant into the filtered lithium bicarbonate solution, and stirring until the surfactant is completely dissolved to obtain a second solution;

adding 40% hydrofluoric acid into the second solution, controlling the pH of the second solution added with the hydrofluoric acid to be 4-5, and obtaining lithium fluoride slurry after the reaction is finished;

performing centrifugal separation on the lithium fluoride slurry to obtain a lithium fluoride wet material;

and drying the obtained lithium fluoride wet material to obtain a final product.

Further, the purity of the lithium carbonate is not lower than 99.9%.

Further, in the first solution, the mass ratio of the lithium carbonate to the pure water is 1: 10-30.

Further, carbon dioxide is introduced into the first solution, and the introduced carbon dioxide hydrogenates the lithium carbonate to obtain a lithium bicarbonate solution, which specifically includes:

the mass ratio of the lithium carbonate to the introduced carbon dioxide is 1: 1-5, and the introduction time of the carbon dioxide is 1-3 hours.

Preferably, the addition amount of the surfactant is 0.01-1% of the mass of the lithium carbonate in the filtered lithium bicarbonate solution.

Further, the surfactant is one or a mixture of several of alkyl ammonium salt with 12-16 carbon atoms, fatty alcohol-polyoxyethylene ether with 11-13 carbon atoms and fatty acid polyglycol ester with 10-24 carbon atoms.

Further, the mass ratio of the mass of the lithium carbonate in the filtered lithium bicarbonate solution to the addition amount of the hydrofluoric acid with the concentration of 40% is 1: 1.35-1.5.

Further, the lithium fluoride slurry is subjected to centrifugal separation to obtain a lithium fluoride wet material, the centrifugal separation is performed at normal temperature, and the maximum rotation speed of the centrifugal separation is 1500 revolutions per minute.

Further, drying the obtained lithium fluoride wet material, wherein the drying temperature is 100-160 ℃.

The invention has the beneficial effects that:

the particle size of the lithium fluoride particles obtained by the method is larger than 120 microns, the crystal structure is regular, the fluidity is obviously improved, and the requirements of some new product preparations on large-particle lithium fluoride raw materials can be met.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the 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.

The embodiment of the invention discloses a preparation method of lithium fluoride, which comprises the following steps:

s1: mixing lithium carbonate with pure water to obtain a first solution;

specifically, further, the purity of lithium carbonate is not lower than 99.9%, and in the first solution, the mass ratio of lithium carbonate to pure water is 1: 10-30.

S2: introducing carbon dioxide into the first solution, and hydrogenating lithium carbonate by the introduced carbon dioxide to obtain a lithium bicarbonate solution;

specifically, the mass ratio of the introduced lithium carbonate to the introduced carbon dioxide is 1: 1-5, and the introduction time of the carbon dioxide is 1-3 hours. The purpose of introducing carbon dioxide in the step is as follows: is prepared from Li₂CO₃Hydrogenation to LiHCO₃，Li₂CO₃Slightly soluble in water, and LiHCO₃Is easy to dissolve in water to form solution, so that the next reaction is more sufficient, and the impurity removing function can be realized, and impurities which are not dissolved in water can be filtered.

S3: and filtering the obtained lithium bicarbonate solution to remove impurities insoluble in water, so that the reaction solution is purer to obtain a product with higher purity, and taking the clarity and transparency of the solution as a filtering standard.

S4: adding a surfactant into the filtered lithium bicarbonate solution, and stirring until the surfactant is completely dissolved to obtain a second solution, wherein the second solution specifically comprises the following components:

the addition amount of the surfactant is 0.01-1% of the mass of the lithium carbonate in the filtered lithium bicarbonate solution, and the surfactant is one or a mixture of alkyl ammonium salt with the carbon atom number of 12-16, fatty alcohol-polyoxyethylene ether with the carbon atom number of 11-13 and fatty acid polyglycol ester with the carbon atom number of 10-24.

In the embodiment of the invention, the surfactant is added into the filtered lithium bicarbonate solution, so that the surface free energy and the thermodynamic property of the solid surface of the filtered lithium bicarbonate solution can be changed, the nucleation rate and the crystal growth rate are influenced, and the size and the shape of the crystal are finally changed.

S5: adding 40% hydrofluoric acid into the second solution, wherein the mass ratio of the mass of the lithium carbonate in the filtered lithium bicarbonate solution to the addition amount of the 40% hydrofluoric acid is 1:1.35-1.5, controlling the pH of the second solution into which the hydrofluoric acid is added to be 4-5, and obtaining lithium fluoride slurry after the reaction is finished;

in this step, hydrofluoric acid having a concentration of 40% is added in order to react the hydrofluoric acid with lithium bicarbonate to produce lithium fluoride.

S6: and (3) performing centrifugal separation on the lithium fluoride slurry to obtain a lithium fluoride wet material, wherein the lithium fluoride can be separated from the mother liquor through the centrifugal separation, the temperature is performed at normal temperature, and the centrifugal maximum rotating speed is 1500 rpm so as to ensure that the lithium fluoride is completely separated from the mother liquor.

S7: and drying the obtained lithium fluoride wet material at the drying temperature of 100-160 ℃, thus obtaining the final product.

The specific application is as follows:

(1) at normal temperature, adding 1kg of lithium carbonate and 20kg of pure water into a reaction kettle, and stirring at 300r/min to form a suspension, wherein the suspension is a first solution;

(2) slowly introducing food-grade carbon dioxide to the bottom of the suspension for hydrogenation reaction, introducing 2kg of carbon dioxide for 3 hours to obtain a lithium bicarbonate solution;

(3) filtering the obtained lithium bicarbonate solution through a precision filter to obtain a pure lithium bicarbonate solution;

(4) adding 1g of dodecyl trimethyl ammonium chloride into the filtered lithium bicarbonate solution, and stirring for 10 minutes to obtain a second solution;

(5) slowly adding 40% hydrofluoric acid solution into the second solution, wherein the adding amount of the 40% hydrofluoric acid solution is 1.375kg, the pH value of the test solution is 5, and finishing the reaction to obtain lithium fluoride slurry;

(6) centrifugally separating the lithium fluoride slurry obtained in the step (1), and then rinsing with deionized water for 2 times to obtain a lithium fluoride wet material;

(7) the obtained lithium fluoride wet material is placed in a Teflon baking pan to be subjected to vacuum at 130 ℃, 697.2g of lithium fluoride product is obtained, the yield is 99.22%, the product is white powder, the particle size is 130.1 microns (measured by a laser particle size analyzer), and the powder repose angle is 30 degrees (measured by a powder repose angle measuring instrument).

In conclusion, the particle size of the lithium fluoride particles obtained by the method is larger than 120 microns, the crystal structure is regular, the fluidity is obviously improved, and the requirements of some new product preparations on large-particle lithium fluoride raw materials can be met.

The following embodiments are provided for the purpose of illustrating the present invention and are not to be construed as limiting the present invention in any way, and it will be apparent to those skilled in the art that the technical features of the present invention can be modified or changed in some ways without departing from the scope of the present invention.