阅读说明：本技术 一种窄粒度分布三元前驱体的制备方法 (Preparation method of ternary precursor with narrow particle size distribution ) 是由 王碧武 朱珠 倪湖炳 于 2020-05-12 设计创作，主要内容包括：本发明提供一种窄粒度分布三元前驱体的制备方法,包括以下步骤：将水、氨水和氢氧化钠溶液在反应釜中混合,得到混合液；反应釜上部侧壁设有第一溢流口和第二溢流口；第一溢流口在距离第二溢流口上方98～102cm处；混合液的液面与第二溢料口的垂直距离为28～32cm；在搅拌下,向混合液中持续通入镍钴锰混合液、氨水和氢氧化钠溶液,进行反应；超过第二溢流口的物料流出反应釜；待反应至产物粒度D50达到要求后关闭第二溢流口,开启第一溢流口,pH值升高后进行打球,且使液面在第一和第二溢流口之间,打球结束后降回至原pH值开始生长,至料液从第一溢流口流出,得到窄粒度分布三元前驱体。该工艺能连续生产,且产品粒度分布较小。(The invention provides a preparation method of a ternary precursor with narrow particle size distribution, which comprises the following steps: mixing water, ammonia water and a sodium hydroxide solution in a reaction kettle to obtain a mixed solution; a first overflow port and a second overflow port are formed in the side wall of the upper part of the reaction kettle; the first overflow port is 98-102 cm away from the upper part of the second overflow port; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 28-32 cm; continuously introducing a nickel-cobalt-manganese mixed solution, ammonia water and a sodium hydroxide solution into the mixed solution under stirring to react; the material exceeding the second overflow port flows out of the reaction kettle; and (3) after the reaction is carried out until the product granularity D50 meets the requirement, closing the second overflow port, opening the first overflow port, carrying out ball hitting after the pH value is increased, enabling the liquid level to be between the first overflow port and the second overflow port, reducing the pH value to the original value after the ball hitting is finished, starting to grow until the feed liquid flows out from the first overflow port, and obtaining the ternary precursor with narrow granularity distribution. The process can realize continuous production, and the product has small particle size distribution.)

1. A preparation method of a ternary precursor with narrow particle size distribution comprises the following steps:

mixing water, ammonia water and a sodium hydroxide solution in a reaction kettle to obtain a mixed solution; a first overflow port and a second overflow port are formed in the side wall of the upper part of the reaction kettle; the first overflow port is 98-102 cm away from the upper part of the second overflow port; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 28-32 cm;

continuously introducing a nickel-cobalt-manganese mixed solution, ammonia water and a sodium hydroxide solution into the mixed solution under a stirring condition to react, wherein the flow rate of the nickel-cobalt-manganese mixed solution is 50-300L/h, the ammonia value of the system is 2-15 g/L by the ammonia water and the sodium hydroxide solution, and the pH value is 9-12; the material exceeding the second overflow port flows out of the reaction kettle;

after the reaction is carried out until the granularity D50 of the product reaches 9.5-10.5 microns, closing the second overflow port, opening the first overflow port, raising the pH value by 0.2-0.6, then carrying out ball hitting for 2-4 h, enabling the liquid level to be between the first overflow port and the second overflow port, reducing the pH value to the original value after the ball hitting is finished, starting to grow, and enabling the feed liquid to flow out from the first overflow port to obtain a ternary precursor with narrow granularity distribution;

and after the granularity D50 exceeds 10.5 mu m, opening the second overflow port, enabling the slurry to flow out until the liquid level is equal to the second overflow port, and repeating the steps of balling and growing.

2. The method of claim 1, wherein the first overflow port is located 100cm above the second overflow port; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 30 cm.

3. The method of claim 1, wherein the time period for returning to the original pH value is 30 to 60 min.

4. The preparation method according to claim 1, wherein the concentration of the nickel-cobalt-manganese mixed solution is 1-5 mol/L;

the molar ratio of nickel ions, cobalt ions and manganese ions in the nickel-cobalt-manganese mixed solution is 3: 0.98-1.02: 0.98-1.02.

5. The preparation method according to claim 1, wherein the concentration of the ammonia water is 3 to 10 mol/L;

the concentration of the sodium hydroxide solution is 1-15 mol/L.

6. The preparation method according to claim 1, wherein the nickel ions in the nickel-cobalt-manganese mixed solution are provided by nickel nitrate, nickel chloride or nickel sulfate;

the cobalt ions are provided by cobalt nitrate, cobalt chloride or cobalt sulfate;

the manganese ions are provided by manganese nitrate, manganese chloride or manganese sulfate.

7. The preparation method according to claim 1, wherein the particle size distribution of the narrow particle size distribution ternary precursor is 0.65-0.85.

Technical Field

The invention belongs to the technical field of ternary precursors, and particularly relates to a preparation method of a ternary precursor with narrow particle size distribution.

Background

The main current preparation method of the ternary precursor is a coprecipitation method, wherein a nickel-cobalt-manganese metal salt solution is used as a raw material, NaOH is used as a precipitator, and ammonia water is used as a complexing agent to perform a complex precipitation reaction in a reaction kettle to obtain a final product. The continuous method is characterized in that after the D50 granularity meets the requirement, the pH value is adjusted to play balls, the D50 is reduced to a certain value, the pH value is adjusted again to slowly grow to the required granularity, then the balls are played, and the process is repeated continuously. Under the process production conditions of the existing continuous method, the particle size distribution of the obtained precursor is wider, and a plurality of small particles can be seen from an electron microscope.

Disclosure of Invention

In view of the above, the present invention provides a method for preparing a ternary precursor with a narrow particle size distribution, which is capable of preparing a precursor with a narrower particle size distribution.

The invention provides a preparation method of a ternary precursor with narrow particle size distribution, which comprises the following steps:

mixing water, ammonia water and a sodium hydroxide solution in a reaction kettle to obtain a mixed solution; a first overflow port and a second overflow port are formed in the side wall of the upper part of the reaction kettle; the first overflow port is 98-102 cm away from the upper part of the second overflow port; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 28-32 cm;

continuously introducing a nickel-cobalt-manganese mixed solution, ammonia water and a sodium hydroxide solution into the mixed solution under a stirring condition to react, wherein the flow rate of the nickel-cobalt-manganese mixed solution is 50-300L/h, the ammonia value of the system is 2-15 g/L by the ammonia water and the sodium hydroxide solution, and the pH value is 9-12; the material exceeding the second overflow port flows out of the reaction kettle;

after the reaction is carried out until the granularity D50 of the product reaches 9.5-10.5 microns, closing the second overflow port, opening the first overflow port, raising the pH value by 0.2-0.6, then carrying out ball hitting for 2-4 h, enabling the liquid level to be between the first overflow port and the second overflow port, reducing the pH value to the original value after the ball hitting is finished, starting to grow, and enabling the feed liquid to flow out from the first overflow port to obtain a ternary precursor with narrow granularity distribution;

and after the granularity D50 exceeds 10.5 mu m, opening the second overflow port, enabling the slurry to flow out until the liquid level is equal to the second overflow port, and repeating the steps of balling and growing.

Preferably, the first overflow outlet is located 100cm above the second overflow outlet; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 30 cm.

Preferably, the time for returning to the original pH value is 30-60 min.

Preferably, the concentration of the nickel-cobalt-manganese mixed solution is 1-5 mol/L;

the molar ratio of nickel ions, cobalt ions and manganese ions in the nickel-cobalt-manganese mixed solution is 3: 0.98-1.02: 0.98-1.02.

Preferably, the concentration of the ammonia water is 3-10 mol/L;

the concentration of the sodium hydroxide solution is 1-15 mol/L.

Preferably, the nickel ions in the nickel-cobalt-manganese mixed solution are provided by nickel nitrate, nickel chloride or nickel sulfate;

the cobalt ions are provided by cobalt nitrate, cobalt chloride or cobalt sulfate;

the manganese ions are provided by manganese nitrate, manganese chloride or manganese sulfate.

Preferably, the particle size distribution of the narrow particle size distribution ternary precursor is 0.65-0.85.

The invention provides a preparation method of a ternary precursor with narrow particle size distribution, which comprises the following steps: mixing water, ammonia water and a sodium hydroxide solution in a reaction kettle to obtain a mixed solution; a first overflow port and a second overflow port are formed in the side wall of the upper part of the reaction kettle; the first overflow port is 98-102 cm away from the upper part of the second overflow port; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 28-32 cm; continuously introducing a nickel-cobalt-manganese mixed solution, ammonia water and a sodium hydroxide solution into the mixed solution under a stirring condition to react, wherein the flow rate of the nickel-cobalt-manganese mixed solution is 50-300L/h, the ammonia value of the system is 2-15 g/L by the ammonia water and the sodium hydroxide solution, and the pH value is 9-12; the material exceeding the second overflow port flows out of the reaction kettle; after the reaction is carried out until the granularity D50 of the product reaches 9.5-10.5 microns, closing the second overflow port, opening the first overflow port, raising the pH value by 0.2-0.6, then carrying out ball hitting for 2-4 h, enabling the liquid level to be between the first overflow port and the second overflow port, reducing the pH value to the original value after the ball hitting is finished, starting to grow, and enabling the feed liquid to flow out from the first overflow port to obtain a ternary precursor with narrow granularity distribution; and after the granularity D50 exceeds 10.5 mu m, opening the second overflow port, enabling the slurry to flow out until the liquid level is equal to the second overflow port, and repeating the steps of balling and growing. According to the invention, the first overflow port and the second overflow port with specific height difference are arranged on the switching reaction kettle, so that the slurry after ball striking continues to grow in the kettle for a period of time without flowing to the aging kettle, full growth of particles is ensured, the number of small particles in a finished product is finally reduced, and the effect of reducing particle size distribution is achieved by combining specific process conditions, and continuous production can be realized. The experimental results show that: the particle size distribution of the ternary precursor is 0.65-0.85.

Drawings

FIG. 1 is a schematic view of a partial structure of a reaction vessel used in the present invention;

FIG. 2 is an SEM image of a ternary precursor prepared according to comparative example 1 of the present invention;

FIG. 3 is an SEM image of a ternary precursor prepared in example 1 of the present invention;

fig. 4 is an SEM image of the ternary precursor prepared in example 2 of the present invention.

Detailed Description

The invention provides a preparation method of a ternary precursor with narrow particle size distribution, which comprises the following steps:

mixing water, ammonia water and a sodium hydroxide solution in a reaction kettle to obtain a mixed solution; a first overflow port and a second overflow port are formed in the side wall of the upper part of the reaction kettle; the first overflow port is 98-102 cm away from the upper part of the second overflow port; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 28-32 cm;

continuously introducing a nickel-cobalt-manganese mixed solution, ammonia water and a sodium hydroxide solution into the mixed solution under a stirring condition to react, wherein the flow rate of the nickel-cobalt-manganese mixed solution is 50-300L/h, the ammonia value of the system is 2-15 g/L by the ammonia water and the sodium hydroxide solution, and the pH value is 9-12; the material exceeding the second overflow port flows out of the reaction kettle;

after the reaction is carried out until the granularity D50 of the product reaches 9.5-10.5 microns, closing the second overflow port, opening the first overflow port, raising the pH value by 0.2-0.6, then carrying out ball hitting for 2-4 h, enabling the liquid level to be between the first overflow port and the second overflow port, reducing the pH value to the original value after the ball hitting is finished, starting to grow, and enabling the feed liquid to flow out from the first overflow port to obtain a ternary precursor with narrow granularity distribution;

and after the granularity D50 exceeds 10.5 mu m, opening the second overflow port, enabling the slurry to flow out until the liquid level is equal to the second overflow port, and repeating the steps of balling and growing.

Fig. 1 is a schematic view of a partial structure of a reaction kettle used in the present invention, wherein a is a first overflow port, and B is a second overflow port.

Mixing water, ammonia water and a sodium hydroxide solution in a reaction kettle to obtain a mixed solution; the lateral wall of the upper part of the reaction kettle is provided with a first overflow port and a second overflow port. In the invention, the concentration of the ammonia water is 3-10 mol/L; in a specific embodiment, the concentration of the ammonia water is 6 mol/L. The concentration of the sodium hydroxide solution is 1-15 mol/L, and in a specific embodiment, the concentration of the sodium hydroxide solution is 8 mol/L. And the ammonia value of the mixed solution obtained after the water, the ammonia water and the sodium hydroxide solution are mixed is 2-15 g/L, and the pH value is 9-12.

The first overflow port is positioned 98-102 cm above the second overflow port, preferably 99-101 cm, and more preferably 100 cm; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 28-32 cm, preferably 29-31 cm, and most preferably 30 cm.

In the invention, preferably, under the condition of stirring, the nickel-cobalt-manganese mixed solution, ammonia water and sodium hydroxide solution are continuously introduced into the mixed solution to carry out reaction. The concentration of the nickel-cobalt-manganese mixed solution is preferably 1-5 mol/L, and in a specific embodiment, the concentration of the nickel-cobalt-manganese ion mixed solution is 1mol/L or 2.5 mol/L; the mol ratio of nickel ions, cobalt ions and manganese ions in the nickel-cobalt-manganese mixed solution is preferably 3: 0.98-1.02: 0.98-1.02, and more preferably 3:1: 1. The nickel ions in the nickel-cobalt-manganese mixed solution are provided by nickel nitrate, nickel chloride or nickel sulfate; the cobalt ions are provided by cobalt nitrate, cobalt chloride or cobalt sulfate; the manganese ions are provided by manganese nitrate, manganese chloride or manganese sulfate. The ammonia water can perform complexation on three metal ions of nickel, cobalt and manganese, so that the three metal ions can be subjected to coprecipitation at the same time, and the obtained product is relatively uniform; originally, the three ions and hydroxide ions have precipitation reaction under alkaline conditions, but the three metal ions have different precipitation capacities, and if ammonia water is not added, the three metal ions are precipitated respectively to obtain uniform products.

In the reaction process, the flow rate of the nickel-cobalt-manganese mixed solution is 50-300L/h, and in the specific embodiment, the flow rate of the nickel-cobalt-manganese mixed solution is 200L/h or 100L/h. The ammonia value of the system is 2-15 g/L and the pH value is 9-12 by the ammonia water and the sodium hydroxide solution; in specific embodiments, the ammonia value is 6g/L or 12g/L and the pH value is 11 or 11.4. And (4) allowing the material exceeding the second overflow port to flow out of the reaction kettle, namely obtaining unqualified slurry.

And (3) after the reaction is carried out until the granularity D50 of the product reaches 9.5-10.5 microns, closing the second overflow port, opening the first overflow port, raising the pH value by 0.2-0.6, then carrying out ball hitting for 2-4 h, enabling the liquid level to be between the first overflow port and the second overflow port, reducing the pH value to the original value after the ball hitting is finished, starting to grow, and enabling the feed liquid to flow out from the first overflow port to obtain the ternary precursor with narrow granularity distribution. Taking out reaction products from the reaction kettle at intervals in the reaction process, and measuring the particle size of the reaction products; for example every two hours. After the granularity D50 reaches 9.5-10.5 mu m, closing the second overflow port, opening the first overflow port, and raising the pH value by 0.2-0.6 on the basis of the first overflow port to play balls; during the process of balling, the growth of the particle size of the reaction product is mainly realized by controlling the alkali content in the solution and is reflected by the pH value, the particle is enlarged at a relatively low pH value, and conversely, the increase of the alkali flow rate and the increase of the pH value can lead the overall particle size of the particle to be reduced. In a specific embodiment, the ball is started when the pH value is increased by 0.4. The time for batting is preferably 2.5-3.5 h, and more preferably 3 h. In the process of batting, the liquid level is controlled between the first overflow port and the second overflow port by controlling the flow rate of the materials. And after the ball is made, the pH value is reduced to the original value and the growth is started until the feed liquid flows out from the first overflow port, and the ternary precursor with narrow particle size distribution is obtained. The pH value of the solution is slowly reduced to the original value; preferably, the pH value is reduced back to the original pH value within 30-60 min after the balling is finished; the first overflow port is opened at the original pH value, and the pH value before the pH value is increased.

In the invention, the particle size distribution of the narrow particle size distribution ternary precursor is preferably 0.65-0.85.

And after the granularity D50 exceeds 10.5 mu m, opening the second overflow port, enabling the slurry to flow out until the liquid level is equal to the second overflow port, and repeating the steps of balling and growing. And opening the second overflow port when the granularity D50 exceeds 10.5 mu m, so that the slurry flows out until the liquid level is equal to the second overflow port, and repeating the steps of balling and growing.

The method obtains the ternary precursor with narrower granularity by improving the continuous process and adjusting the structure of the reaction kettle, and combines the advantages of low cost and high quality of the continuous process and narrow granularity distribution of the batch process.

In order to further illustrate the present invention, the following examples are provided to describe the preparation method of the narrow particle size distribution ternary precursor of the present invention in detail, but they should not be construed as limiting the scope of the present invention.

Comparative example 1

1) Preparing 2.5mol/L mixed solution of nickel, cobalt and manganese ions, wherein the content ratio of nickel, cobalt and manganese ions is 3:1: 1; the complexing agent is 6mol/L ammonia water, and the precipitator is 8mol/L NaOH solution;

2) mixing 9418L of deionized water, 580L of ammonia water and 1.25L of sodium hydroxide solution to obtain a mixed solution; a first overflow port and a second overflow port are formed in the side wall of the upper part of the reaction kettle; the first overflow port is positioned at a position 100cm above the second overflow port; the vertical distance between the liquid level of the mixed liquid and the second overflow port is 30 cm;

3) and (3) stably and continuously introducing the mixed solution, ammonia water and NaOH solution into the mixed solution through a metering pump for reaction, and balling after the pH value is increased by 0.4 when the reaction granularity D50 reaches 10 micrometers, wherein the slurry flows out through a discharge hole B in the whole process to obtain the ternary precursor.

FIG. 2 is an SEM image of a ternary precursor prepared according to comparative example 1 of the present invention; as can be seen in fig. 2, many irregular small particles were present in the product prepared in comparative example 1.

The particle size distribution of the ternary precursor prepared in comparative example 1 was 1.15.