CN112320854A

CN112320854A - Method for improving production rate of cobaltosic oxide

Info

Publication number: CN112320854A
Application number: CN202011156871.4A
Authority: CN
Inventors: 沈国庆; 辛勇诚
Original assignee: Hefei Youngy Metal Technology Co ltd
Current assignee: Hefei Youngy Metal Technology Co ltd
Priority date: 2020-10-26
Filing date: 2020-10-26
Publication date: 2021-02-05

Abstract

The invention discloses a method for improving the production rate of cobaltosic oxide, because carbon dioxide is generated when carbonate precipitant reacts with cobalt salt, ammonia water or gaseous ammonia gas is added in the reaction, the forward reaction can be promoted, the conversion rate is improved, the precipitation reaction is settled and separated by self gravity and intermolecular repulsion, the precipitation efficiency can be improved by adding flocculant, the molecular-level adhesive bond disappears after high-temperature calcination to form stable cobaltosic oxide, the flocculant is mainly divided into inorganic flocculant and organic flocculant at present, mainly an aluminum flocculant or an organic polymer flocculant is selected, in addition, the performance of the product can be improved by adding aluminum to the cobaltosic oxide, the aluminum-doped cobaltosic oxide is formed, and whether to wash clean aluminum can be selected according to requirements in the later synthesis stage.

Description

Method for improving production rate of cobaltosic oxide

Technical Field

The invention belongs to the technical field of chemical raw material production, and particularly relates to a method for improving the production rate of cobaltosic oxide.

Background

The cobaltosic oxide is an important precursor material for preparing lithium battery materials, the main production method of the cobaltosic oxide is a precipitation crystallization and heat treatment technology, the main raw materials of the precipitation crystallization are cobalt salt and carbonate or strong base, the generated precipitate is washed and centrifuged and then is roasted in a kiln to obtain the cobaltosic oxide, along with the explosive growth of electronic products, the demand on the lithium battery materials is increasingly vigorous, high-quality cobaltosic oxide is developed, and the important promotion effect is played for the whole industry. Meanwhile, the explosive growth of the industry also brings the demand on the amount of cobaltosic oxide, the improvement of the reaction rate and the improvement of the conversion rate by utilizing the existing productivity are important technical improvement directions, and the invention is very helpful for increasing the yield.

Disclosure of Invention

The invention aims to provide a method for improving the production rate of cobaltosic oxide, because carbon dioxide is generated when a carbonate precipitator reacts with cobalt salt, ammonia water or gaseous ammonia gas is added in the reaction, the forward direction of the reaction can be promoted, and the conversion rate is improved. The precipitation reaction is subjected to precipitation separation by virtue of self gravity and intermolecular repulsion, the precipitation efficiency can be improved by adding the flocculating agent, and the molecular-level adhesive bond disappears after high-temperature calcination to form stable cobaltosic oxide. At present, flocculants are mainly divided into inorganic flocculants and organic flocculants, aluminum flocculants or organic polymer flocculants are mainly selected, in addition, the performance of the product can be improved by adding aluminum into the cobaltosic oxide, the aluminum-doped cobaltosic oxide is formed, and whether the aluminum is washed clean or not can be selected according to requirements in the later synthesis stage.

The purpose of the invention can be realized by the following technical scheme:

the invention provides a scheme for improving the product conversion rate and the precipitation rate in the synthesis process of the cobaltosic oxide and achieving the purpose of improving the productivity, and in addition, the aluminum flocculant or the organic polymer flocculant can synthesize high-quality aluminum-doped cobaltosic oxide.

The invention provides a method for improving the yield of cobaltosic oxide, which comprises the following steps:

firstly, preparing a cobalt salt solution, a precipitator solution and a precipitation accelerator solution, and simultaneously introducing the precipitation accelerator solution for improving the reaction conversion rate in the reaction process of the precipitator solution and the cobalt salt solution;

secondly, stirring and mixing the components together under the conditions that the pH value is 7-12 and the temperature is 40-70 ℃, and the stirring speed is 20-50Hz to obtain a precursor;

and thirdly, washing and centrifugally filtering the precursor obtained in the second step, and roasting at the temperature of 500-800 ℃ for 3-6h to obtain the finished cobaltosic oxide.

In the second step, the flow rate of the cobalt salt solution is 500-1000L/h, the flow rate of the precipitant solution is 600-1000L/h, and the flow rate of the promoter solution is 5-20L/h when the cobalt salt solution and the precipitant solution are mixed together.

As a further embodiment of the present invention, the volume percentage of the accelerator in the mixed solution is 0.4-1%.

As a further embodiment of the invention, the concentration of the cobalt salt solution is 1-2mol/L,

as a further embodiment of the invention, the concentration of the precipitant solution is 2.2 to 4.4 mol/L.

As a further scheme of the invention, the precipitation promoter is one or a mixture of more of ammonia water, ammonia gas and aluminum salt flocculant.

As a further scheme of the invention, the cobalt salt is one or a mixture of two of cobalt sulfate and cobalt chloride.

As a further embodiment of the present invention, the precipitant is one of sodium hydroxide or ammonium bicarbonate.

As a further aspect of the invention, when an aluminum flocculant is used as the precipitation promoter substance, either the aluminum can be washed clean to obtain pure cobalt precipitate or the aluminum-doped cobalt precipitate can be obtained without washing the aluminum.

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

(1) the cobalt salt reacts with the precipitator and simultaneously adds the precipitation accelerant, the reaction condition is pH value 7-12, stirring speed is 20-50Hz, feeding speed is respectively 1000L/h of cobalt salt solution 500-.

(2) In the reaction process, an aluminum flocculant or an organic polymer flocculant is added to increase the precipitation rate, a uniform mesh structure of the flocculant and the precipitate is formed, the precipitate particles are uniform and have a regular shape, and the flocculant can be oxidized and sintered to obtain uniform cobaltosic oxide after being roasted at the temperature of 500-800 ℃ for 3-6 h.

(3) The invention adopts the aluminum inorganic flocculant sediment, can wash aluminum and not wash aluminum according to the requirement to obtain aluminum-doped or non-doped cobalt sediment, and obtains aluminum-doped or non-doped cobaltosic oxide through sintering, and the aluminum-doped cobaltosic oxide is more uniform in aluminum doping because a net structure is formed.

Drawings

The invention is described in further detail below with reference to the figures and specific embodiments.

FIG. 1 is a topographical view of tricobalt tetroxide prepared in example 2;

fig. 2 is a morphology diagram of the cobaltosic oxide prepared in comparative example 1.

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.

Example 1

Cobalt-containing mineral aggregate is adopted as a raw material, 100g/l of cobalt sulfate solution is prepared after leaching extraction, and the cobalt sulfate solution reacts with 200g/l of ammonium bicarbonate solution, the flow rate of the cobalt sulfate solution is 600L l/h and the flow rate of the ammonium bicarbonate solution is 650l/h during reaction, ammonia water is synchronously added, the pH value is controlled to be 9.0, the stirring speed is 35HZ, the pH value is regulated to be 8.0 when the reaction end point is reached, the stirring speed is regulated according to current, and the stirring degree is controlled to be 28HZ at the later reaction stage. And washing the obtained precursor, and then feeding the washed precursor into a rotary kiln for roasting at the roasting temperature of 800 ℃ for 3 hours to obtain the cobaltosic oxide.

Example 2

Preparing 100g/L of cobalt sulfate solution, preparing 200g/L of ammonium bicarbonate solution, preparing 0.1mg/L of polyacrylamide flocculant, starting adding the polyacrylamide solution after the cobalt sulfate and the ammonium bicarbonate react for half an hour, controlling the adding speed according to the size of formed vanadium flowers, controlling the speed at 1L/h, controlling the reaction pH value at 8.0, stirring the solution at the speed of 35Hz, controlling the flow rate of the cobalt sulfate solution at 600L L/h and the flow rate of the ammonium bicarbonate solution at 650L/h during the reaction until the reaction end point, taking out the precipitate, washing the precipitate, and roasting at 800 ℃ to prepare the cobaltosic oxide.

Example 3

The method comprises the steps of taking cobalt-containing mineral aggregate as a raw material, preparing 100g/l of cobalt chloride solution after leaching extraction, manually preparing 200g/l of sodium hydroxide solution, controlling the flow rate of the cobalt chloride solution to be 600l/h and the flow rate of the sodium hydroxide to be 200l/h, stirring at the speed of 35Hz, reacting for half an hour, adding a mixture of aluminum sulfate and polyacrylamide, adjusting the weight ratio of the aluminum sulfate to the polyacrylamide to be 1:0.5, controlling the adding speed of the mixture of the aluminum sulfate and the polyacrylamide to be about 1l/h according to the situation of vanadium flower, washing precipitates after the reaction is finished, centrifuging, roasting, and sintering at 800 ℃ for 3 hours to prepare the aluminum-doped cobaltosic oxide.

Example 4

The method comprises the steps of preparing 100g/l of cobalt sulfate solution after leaching and extraction, reacting with 200g/l of ammonium bicarbonate solution, synchronously introducing ammonia gas, introducing the ammonia gas with the pressure of 0.1MPA and the flow rate of 0.05l/h, controlling the pH value to be about 9.0, and controlling the stirring speed to be 35HZ, wherein the flow rate of the cobalt sulfate solution is 600L l/h and the flow rate of the ammonium bicarbonate solution is 650l/h during reaction, the pH value is regulated and controlled to be 8.0 when the reaction end point is reached, the stirring speed is regulated according to current, and the stirring degree is controlled to be 28HZ at the later stage of the. And washing the obtained precursor, and then feeding the washed precursor into a rotary kiln for roasting at the roasting temperature of 800 ℃ for 3 hours to obtain the cobaltosic oxide.

Comparative example 1

Cobalt-containing mineral aggregate is adopted as a raw material, 100g/l of cobalt sulfate solution is prepared after leaching and extraction, and the cobalt sulfate solution reacts with 200g/l of ammonium bicarbonate solution, the flow rate of the cobalt sulfate solution is 600L l/h, the flow rate of the ammonium bicarbonate solution is 650l/h, the pH value is controlled to be about 8.0, and the stirring speed is 35 HZ. And regulating the pH value to be 7.2 when the reaction end point is reached, regulating the stirring speed according to the current, and controlling the stirring degree to be 28HZ at the later stage of the reaction. And washing the obtained precursor, and then feeding the washed precursor into a rotary kiln for roasting at the roasting temperature of 800 ℃ for 3 hours to obtain the cobaltosic oxide.

Comparative example 2

Cobalt-containing mineral aggregate is adopted as a raw material, 100g/l of cobalt chloride solution is prepared after leaching extraction, 200g/l of sodium hydroxide solution is manually prepared, the flow rate of the cobalt chloride solution is 600l/h, the flow rate of the sodium hydroxide is 200l/h, and the stirring speed is 35 Hz. And washing the precipitate after the reaction is finished, centrifuging, roasting, and sintering at 800 ℃ for 3h to prepare the cobaltosic oxide.

Comparative example 3

Preparing 100g/l of cobalt sulfate solution, preparing 200g/l of ammonium bicarbonate solution, preparing 10g/l of aluminum sulfate solution, preparing uniform solution A from aluminum sulfate and cobalt sulfate according to the volume ratio of 20:1, introducing the solution A and the ammonium bicarbonate solution into a reaction kettle at the flow rates of 1000l/h and 1000l/h respectively, stirring at the speed of 35HZ, and preparing carbonate precipitate at the pH value of 8.0. And washing the precipitate, and centrifugally roasting to obtain the aluminum-doped cobaltosic oxide.

Test example

Topography analysis

Fig. 1 and fig. 2 are the morphology diagrams of example 2 and comparative example 1, and it can be seen that the morphology of fig. 1 is more uniform and ordered, which is very helpful for improving electrical properties.

Analysis of reaction time

When the reaction time and the particle size of the precipitate were measured and compared when the reaction was terminated at the same full pot volume in the examples and comparative examples of the present invention, the results are shown in the following Table 1:

TABLE 1

As shown in Table 1, the precipitation accelerator has no influence on the particle size under the reaction conditions, the average saving time is about 26%, the reaction rate is greatly improved, and the yield is effectively improved.

The foregoing is merely exemplary and illustrative of the present invention and various modifications, additions and substitutions may be made by those skilled in the art to the specific embodiments described without departing from the scope of the invention as defined in the following claims.

Claims

1. A method for increasing the production rate of cobaltosic oxide, comprising the steps of:

2. The method for increasing the productivity of cobaltosic oxide according to claim 1, wherein the stirring speed in the second step of the co-stirring and mixing is 25 to 45 Hz.

3. The method as claimed in claim 2, wherein the flow rate of the cobalt salt solution is 500-1000L/h, the flow rate of the precipitant solution is 600-1000L/h, and the flow rate of the precipitation promoter solution is 5-20L/h during the co-stirring and mixing in the second step.

4. The method of claim 1, wherein the precipitation promoter is one or more of ammonia, aluminum salt flocculant, and organic polymer flocculant.

5. The method for increasing the productivity of cobaltosic oxide according to claim 4, wherein the volume percentage of the precipitation accelerator in the mixed solution of the cobalt salt solution, the precipitant solution and the precipitation accelerator solution in the first step is 0.4-1%.

6. A method for increasing the productivity of cobaltosic oxide according to claim 1, wherein the cobalt salt is a mixture of cobalt sulfate and one or both of cobalt chloride.

7. The method for improving the production rate of cobaltosic oxide according to claim 6, wherein the concentration of the cobalt salt solution is 1-2mol/L based on the molar amount of cobalt ions.

8. The method of claim 1, wherein the precipitant is sodium hydroxide or ammonium bicarbonate.

9. The method for increasing the production rate of cobaltosic oxide according to claim 8, wherein the concentration of said precipitant solution is 2.0-4.4 mol/L.

10. The method of claim 1, wherein when the precipitation promoter used in the first and second steps is an aluminum salt flocculant, the aluminum can be washed clean in the third step to obtain pure cobalt precipitate or the aluminum-doped cobalt precipitate can be obtained without washing the aluminum.