阅读说明：本技术 一种窄分布中粒度四氧化三钴的制备方法 (Preparation method of narrow-distribution medium-particle-size cobaltosic oxide ) 是由 谭玉虎 汤玲花 赵宗明 丁冬久 初旭 常开善 王平德 王飞 于 2021-08-25 设计创作，主要内容包括：一种窄分布中粒度四氧化三钴的制备方法,包括以下步骤：溶液的配制,合成反应,过滤、洗涤及干燥。本发明合成采用高浓度溶液,大流量进料,大大提升生产效率；通过过程PH阶段性调整,控制生长速度,改善产品形貌,杜绝微粉产出；采用本发明方法制备出的窄分布中粒度四氧化三钴产品粒度分布较好,Dmin≥2um,D-(10)≥4-6um,D-(50):7.5-9um,Dmax≤35um,(D90-D10)/D50≤85%。(A preparation method of narrow-distribution medium-particle-size cobaltosic oxide comprises the following steps: preparing solution, synthesizing reaction, filtering, washing and drying. The synthesis of the invention adopts high-concentration solution, and the feeding is carried out at a large flow rate, thus greatly improving the production efficiency; through the process of pH staged adjustment, the growth speed is controlled, the product appearance is improved, and the output of micro powder is avoided; the narrow-distribution medium-particle-size cobaltosic oxide product prepared by the method has good particle size distribution, Dmin is more than or equal to 2um, and D 10 ≥4‑6um，D 50 :7.5‑9um，Dmax≤35um，（D90‑D10）/D50≤85%。)

1. A preparation method of narrow-distribution medium-particle-size cobaltosic oxide is characterized by comprising the following steps of:

a. preparing a solution A with the cobalt concentration of Xg/L by taking cobalt salt as a raw material, preparing a solution B with the concentration of Yg/L by taking sodium hydroxide as a raw material, and adding an ammonia water solution with the volume of 0.04-0.06 time and the concentration of 180-200g/L into the solution B; storing the prepared solution for later use;

b. adding hot pure water with a fixed volume into each kettle as a synthesis buffer solution, controlling the temperature and stirring, then sequentially adding solution A and solution B, setting the flow rate of the solution A, adjusting and controlling the pH =7.8-8.6 in stages, stabilizing the flow rate of the solution B, synthesizing for 18-20 hours, detecting the granularity, and performing subsequent processes when the granularity reaches the required index;

c. after the synthesis is finished, the slurry is centrifugally washed by deionized water at 80-100 ℃, dried at 100-120 ℃, and calcined at 750-800 ℃ in a rotary kiln to obtain the narrow-distribution medium-granularity cobaltosic oxide product.

2. The method for preparing the narrow-distribution medium-particle-size cobaltosic oxide according to claim 1, wherein the narrow-distribution medium-particle-size cobaltosic oxide is prepared by the following steps: and in the step a, the cobalt salt is cobalt nitrate or cobalt chloride.

3. The method for preparing large-particle-size aluminum-coated cobaltosic oxide according to claim 1, wherein the method comprises the following steps: the concentration of the solution A in the step a is 120g/L of 110-3000 g/L, and the concentration of the solution B is 3000g/L of 250-3000 g/L.

4. The method for preparing large-particle-size aluminum-coated cobaltosic oxide according to claim 1, wherein the method comprises the following steps: the flow rate of the solution A in the step B is 400-500L/h, and the flow rate of the solution B is 200-300L/h.

5. The method for preparing large-particle-size aluminum-coated cobaltosic oxide according to claim 1, wherein the method comprises the following steps: the pH value in the step b is adjusted in stages as follows: 1-10 h: 8.4-8.6, 10-15 h: 8.2-8.4, after 15 h: 7.8-8.2.

Technical Field

The invention belongs to the technical field of lithium ion batteries, and particularly relates to a method for preparing cobaltosic oxide with medium particle size in narrow distribution of a precursor of a positive electrode material of a lithium cobalt oxide battery.

Background

The lithium ion battery prepared by taking lithium cobaltate as the anode material has the characteristics of light weight, large capacity, high specific energy, high working voltage, stable discharge, suitability for large-current discharge, good cycle performance, long service life and the like, and is mainly applied to the field of 3C digital codes.

Lithium cobaltate is developing towards high voltage, high compaction and high cycle performance, and thus, the requirement for the raw material cobaltosic oxide is increasing. Co₃O₄Is a functional material with special structure and performance, and how to prepare the high-performance narrow-distribution medium-particle-size cobaltosic oxide is particularly important.

The prior preparation process of hydroxyl cobaltosic oxide has the following problems: the small particles (micro powder) have higher proportion, and have larger influence on the subsequent preparation of the anode material; dmax is generally large; the overall particle size distribution is poor, and the ratio of (D90-D10)/D50 is basically over 95 percent; the product appearance is poor.

Disclosure of Invention

The invention aims to overcome the problems in the prior art and provide the preparation method of the cobaltosic oxide, which has the advantages of high production efficiency, narrow product particle size distribution and good appearance.

The invention relates to a preparation method of narrow-distribution medium-particle-size cobaltosic oxide, which comprises the following steps of:

a. preparing a solution A with the cobalt concentration of Xg/L by taking cobalt salt as a raw material, preparing a solution B with the concentration of Yg/L by taking sodium hydroxide as a raw material, and adding an ammonia water solution with the volume of 0.04-0.06 time and the concentration of 180-200g/L into the solution B; storing the prepared solution for later use;

b. adding hot pure water with a fixed volume into each kettle as a synthesis buffer solution, controlling the temperature and stirring, then sequentially adding solution A and solution B, setting the flow rate of the solution A, adjusting and controlling the pH =7.8-8.6 in stages, stabilizing the flow rate of the solution B, synthesizing for 18-20 hours, detecting the granularity, and performing subsequent processes when the granularity reaches the required index;

c. after the synthesis is finished, the slurry is centrifugally washed by deionized water at 80-100 ℃, dried at 100-120 ℃, and calcined at 750-800 ℃ in a rotary kiln to obtain the narrow-distribution medium-granularity cobaltosic oxide product.

And in the step a, the cobalt salt is cobalt nitrate or cobalt chloride.

The concentration of the solution A in the step a is 120g/L of 110-3000 g/L, and the concentration of the solution B is 3000g/L of 250-3000 g/L.

The flow rate of the solution A in the step B is 400-500L/h, and the flow rate of the solution B is 200-300L/h.

The pH value in the step b is adjusted in stages as follows: 1-10 h: 8.4-8.6, 10-15 h: 8.2-8.4, after 15 h: 7.8-8.2.

Compared with the prior art, the invention has the following advantages: the synthesis adopts high-concentration solution, and the feeding is carried out at a large flow rate, so that the production efficiency is greatly improved; through the process of pH staged adjustment, the growth speed is controlled, the product appearance is improved, and the output of micro powder is avoided; the narrow-distribution medium-particle-size cobaltosic oxide product prepared by the method has good particle size distribution, Dmin is more than or equal to 2um, and D₁₀≥4-6um，D₅₀:7.5-9um，Dmax≤35um，（D90-D10）/D50≤85%。

Drawings

FIG. 1 is a flow chart of a process employing the present invention.

FIG. 2 is a graph showing the results of detection of the product synthesized by the preparation method of the present invention.

Fig. 3 is a graph showing the results of detection of the product calcined by the preparation method of the present invention.

Detailed Description

The following will clearly and completely describe the technical solutions in 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 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 preparation method of the narrow-distribution medium-particle-size cobaltosic oxide shown in the figure 1 comprises the following steps of:

a. preparing a solution A with the cobalt concentration of Xg/L by taking cobalt salt as a raw material, preparing a solution B with the concentration of Yg/L by taking sodium hydroxide as a raw material, and adding an ammonia water solution with the volume of 0.04-0.06 time and the concentration of 180-200g/L into the solution B; storing the prepared solution for later use;

b. adding hot pure water with a fixed volume into each kettle as a synthesis buffer solution, controlling the temperature and stirring, then sequentially adding solution A and solution B, setting the flow rate of the solution A, adjusting and controlling the pH =7.8-8.6 in stages, stabilizing the flow rate of the solution B, synthesizing for 18-20 hours, detecting the granularity, and performing subsequent processes when the granularity reaches the required index;

c. after the synthesis is finished, the slurry is centrifugally washed by deionized water at 80-100 ℃, dried at 100-120 ℃, and calcined at 750-800 ℃ in a rotary kiln to obtain the narrow-distribution medium-granularity cobaltosic oxide product.

In the step a, the cobalt salt is cobalt nitrate or cobalt chloride, the concentration of the solution A is 120g/L, and the concentration of the solution B is 3000 g/L; in the step B, the flow rate of the solution A is 400-500L/h, the flow rate of the solution B is 200-300L/h, and the pH is adjusted by stages as follows: 1-10 h: 8.4-8.6, 10-15 h: 8.2-8.4, after 15 h: 7.8-8.2.

DETAILED DESCRIPTION OF EMBODIMENT (S) OF INVENTION

1. Preparing a cobalt solution with the cobalt concentration of 110-120g/L as an A solution and a B solution with the cobalt concentration of 250-300g/L, and adding an ammonia water solution with the volume of 0.04-0.06 time and the concentration of 180g/L into the B solution; 5-8L of additive hydrazine hydrate is solution C; and storing the prepared solution for later use.

2. Adding hot pure water with a fixed volume into each kettle as a synthesis buffer solution, controlling the temperature at 74-76 ℃, stirring at a rotating speed of 35HZ, then sequentially adding the solution A and the solution B, controlling the flow rate of the solution A at 400 +/-30L/h, then controlling the pH =7.8-8.6 according to the process, stabilizing the flow rate of the solution B, synthesizing for 20-25 hours, and performing subsequent procedures after the D50 reaches 8.5-9.5 um.

3. After the synthesis is finished, the slurry is centrifugally washed by deionized water at 80-100 ℃, dried at 100-120 ℃, and calcined at 750-800 ℃ in a rotary kiln to obtain the narrow-distribution medium-granularity cobaltosic oxide product.

The method adopts high-concentration and high-flow solution, and has the advantages of high yield, narrow particle size distribution after synthesis, no micro powder in the product, excellent washing effect, low water content after washing and low drying temperature through pH stage regulation in the process.

The above description is only for the preferred embodiments of the present invention, but the protection scope of the present invention is not limited thereto, and any person skilled in the art can substitute or change the technical solution of the present invention and the inventive concept thereof within the scope of the present invention.