阅读说明：本技术 一种三元正极材料前驱体自动控制进料系统 (Ternary cathode material precursor automatic control feeding system ) 是由 许开华 蒋振康 张坤 李聪 孙海波 陈康 黎俊 范亮姣 于 2019-09-27 设计创作，主要内容包括：本发明属于三元正极材料前驱体制备技术领域,公开了一种三元正极材料前驱体自动控制进料系统,包括控制器,及与控制器电性连接的进料模块、计时模块和输入单元；进料模块用于将各种反应物料以并流的方式输送到反应釜内；计时模块用于记录每次反应的实际累计时间；输入单元用于输入三元正极材料前驱体的各反应物料的预设流速；输入单元用于输入每次反应的预设累计时间或三元正极材料前驱体的预设D50；输入单元用于输入三元正极材料前驱体的实际D50；控制器根据预设累计时间或预设D50与预设流速之间的关系,并结合实际累计时间或实际D50,控制进料模块对各反应物料的输送速度。本发明的控制系统能够得到稳定性较好的产品。(The invention belongs to the technical field of preparation of ternary cathode material precursors, and discloses an automatic control feeding system of a ternary cathode material precursor, which comprises a controller, a feeding module, a timing module and an input unit, wherein the feeding module, the timing module and the input unit are electrically connected with the controller; the feeding module is used for conveying various reaction materials into the reaction kettle in a parallel flow mode; the timing module is used for recording the actual accumulated time of each reaction; the input unit is used for inputting the preset flow rate of each reaction material of the ternary anode material precursor; the input unit is used for inputting preset integration time of each reaction or preset D50 of a ternary positive electrode material precursor; the input unit is used for inputting the actual D50 of the ternary cathode material precursor; the controller controls the conveying speed of each reaction material by the feeding module according to the preset accumulated time or the relation between the preset D50 and the preset flow rate and the combination of the actual accumulated time or the actual D50. The control system can obtain products with better stability.)

1. An automatic control feeding system for a ternary anode material precursor is characterized by comprising a feeding module, a timing module, an input unit and a controller;

the feeding module, the timing module and the input unit are all electrically connected with the controller;

the feeding module is used for conveying each reaction material required for preparing the ternary cathode material precursor into a reaction kettle containing a base solution in a parallel flow mode;

the timing module is used for recording the actual accumulated time of each reaction and sending the actual accumulated time to the controller;

the input unit is used for inputting the preset flow rate of each reaction material of the ternary cathode material precursor; the preset D50 is used for inputting the preset accumulated time of each reaction or the precursor of the ternary cathode material; actual D50 for input of the ternary positive electrode material precursor;

the controller is used for receiving the actual accumulated time or the actual D50 and controlling the feeding speed of each reaction material according to the preset accumulated time or the relation between the preset D50 and the preset flow rate of each reaction material.

2. The ternary positive electrode material precursor automatic control feed system of claim 1, wherein the feed modules comprise a first feed module, a second feed module, and a third feed module;

the first feeding module is used for conveying the ternary mixed solution into the reaction kettle;

the second feeding module is used for conveying the alkali solution into the reaction kettle;

the third feeding module is used for conveying ammonia solution into the reaction kettle.

3. The automatic control feeding system of a ternary cathode material precursor as claimed in claim 1, further comprising a mass flow meter for monitoring the flow rate of the feeding module, and a frequency converter for regulating the flow rate of the feeding module; the mass flow meter is arranged on the feeding module and is electrically connected with the controller; the feeding module is electrically connected with the controller through the frequency converter.

4. The automatic ternary cathode material precursor feeding system according to claim 1, further comprising a temperature detection module, wherein the temperature detection module is electrically connected to the controller;

the temperature detection module is used for detecting the temperature in the reaction kettle and sending the result to the controller.

5. The automatic ternary positive electrode material precursor feed system of claim 1, further comprising a display module, wherein the display module is electrically connected to the controller.

6. The automatic ternary cathode material precursor feeding system according to claim 1, further comprising a pH detection module for detecting pH in the reaction kettle, wherein the pH detection module is electrically connected to the controller.

7. The ternary positive electrode material precursor automatic control feed system of any one of claims 1 to 6, wherein the feed module is a metering pump.

8. The automatic ternary positive electrode material precursor feeding system according to claim 7, wherein the actual flow rate of the metering pump is 30-100% of the rated flow rate of the metering pump.

Technical Field

The invention belongs to the technical field of preparation of ternary cathode material precursors, and particularly relates to an automatic control feeding system for a ternary cathode material precursor.

Background

The existing process for industrially producing the precursor of the ternary cathode material is to add a reaction material containing various metal ions, an alkali solution and an ammonia solution into a reaction kettle at a certain flow rate for reaction, the stability of various parameters in the reaction process has very important influence on the reaction process, the product form and the like, and especially the fluctuation of pH can cause very adverse influence on the product quality. Although the reaction kettle is equipped with a device for monitoring the temperature and a device for monitoring the reaction pH on line (such as an on-line pH meter) in the industrial production process, the accuracy of the on-line detection value is difficult to ensure because the reaction temperature is high, the reaction time is long, and the on-line pH meter cannot be corrected in time; in addition, because pH is sensitive to temperature, temperature fluctuation can also cause reaction pH fluctuation, and therefore online pH in an industrial production process is generally only used as a reference.

In order to better monitor the reaction process of the ternary precursor, the reaction pH, the total alkali, the ammonia concentration and the particle size distribution can be detected by sampling at regular time in the specific production process. However, when the same sample is tested by using different pH meters, the detection results can be different; even if the same pH meter is used for testing, the accuracy of the test result is difficult to ensure due to the sampling amount, the electrode insertion position and the like. The total alkalinity and the ammonia concentration are generally detected by adopting an artificial titration method, and the influence of human factors is large. And because the reaction pH and the ammonia concentration need to be controlled within a certain range in the ternary precursor reaction process, the ammonia-base flow rate needs to be finely adjusted according to the detection result, so that under the condition that the accuracy of the detection result is deviated, the requirement on the experience of staff is higher when the ammonia-base flow rate is finely adjusted, and the poor stability among different batches of the same product is easily caused. Furthermore, because workers have limited energy, if increased production capacity is desired, more labor costs are incurred, thereby increasing production costs.

Disclosure of Invention

In view of this, the invention provides an automatic control feeding system for a ternary cathode material precursor, which aims to solve the problem of poor product stability caused by manual feeding in the process of producing the ternary cathode material precursor.

An automatic control feeding system for a ternary anode material precursor comprises a feeding module, a timing module, an input unit and a controller;

the feeding module, the timing module and the input unit are electrically connected with the controller;

the feeding module is used for conveying each reaction material required for preparing the ternary cathode material precursor into a reaction kettle containing a base solution in a parallel flow mode;

the timing module is used for recording the actual accumulated time of each reaction and sending the actual accumulated time to the controller;

the input unit is used for inputting the preset flow rate of each reaction material of the ternary anode material precursor; a preset D50 for inputting a preset integration time or a ternary positive electrode material precursor of each reaction; actual D50 for input of ternary positive electrode material precursor;

the controller is used for receiving the actual accumulated time or the actual D50, and controlling the conveying speed of the feeding module to each reaction material according to the preset accumulated time or the relation between the preset D50 and the preset flow rate and by combining the actual accumulated time or the actual D50.

Preferably, the feeding modules comprise a first feeding module, a second feeding module and a third feeding module;

the first feeding module is used for conveying the ternary mixed solution into the reaction kettle;

the second feeding module is used for conveying the alkali solution into the reaction kettle;

and the third feeding module is used for conveying the ammonia solution into the reaction kettle.

Preferably, the system comprises a mass flowmeter for detecting the flow rate of the feeding module and a frequency converter for regulating and controlling the flow of the feeding module; the mass flow meter is arranged on the feeding module and is electrically connected with the controller; the feeding module is electrically connected with the controller through the frequency converter.

Preferably, the temperature detection module is electrically connected with the controller;

the temperature detection module is used for detecting the temperature in the reaction kettle and sending the result to the controller.

Preferably, the display device comprises a display module, and the display module is electrically connected with the input unit.

Preferably, the pH detection device comprises a pH detection module for detecting the pH in the reaction kettle, and the pH detection module is electrically connected with the controller.

Preferably, the feed module is a metering pump.

Preferably, the actual flow rate of the metering pump is 30-100% of the rated flow rate of the metering pump.

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

through the automatic control feeding system, when the same type of ternary cathode materials with the same particle size requirement are produced, a worker can input the preset accumulated time or the preset D50 of each reaction and the preset flow rate of each reaction material into the input unit; the controller automatically controls the conveying speed of the feeding module to each reaction material according to the relation between the preset accumulation time or the preset D50 and the preset flow rate and by combining the actual accumulation time or the actual D50, so that the reaction scale can be increased on the premise of not increasing the number of workers, and the production cost is reduced;

in addition, in the traditional preparation process of the ternary cathode material precursor, because workers need to regulate and control the feeding speed of an alkali solution and an ammonia solution according to the detected reaction pH value and the detected ammonia concentration of a supernatant, and because the pH value of the reaction and the ammonia concentration of the supernatant have the problem of inaccurate detection, the wrong judgment of the workers can be possibly caused, so that the stability of the produced ternary precursors of each batch is poor.

In the whole feeding process, manual operation is not needed, so that the fluctuation and even disqualification of the product quality caused by misoperation are avoided. Meanwhile, due to the high precision of the feeding system and the fact that products of the same type are produced by the same parameters, the stability of the products in different batches can be guaranteed, and the product quality is improved.

Drawings

FIG. 1 is a schematic diagram of an automatic control feeding system for a ternary cathode material precursor provided by the invention;

FIG. 2 is a graph showing the relationship between the preset D50 and the material flow rate in the automatic continuous feeding process in example 1 of the present invention;

FIG. 3 is a diagram showing the relationship between the preset cumulative time and the flow rate of the material in the automatic feeding process of the batch process in example 2 of the present invention;

FIG. 4 is a scanning electron microscope image of a ternary cathode material precursor NCM811 according to example 1 of the present invention;

fig. 5 is a scanning electron microscope image of the ternary positive electrode material precursor NCM712 according to example 2 of the present invention.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail with reference to the following embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

The embodiment provides an automatic control feeding system for a ternary cathode material precursor, as shown in fig. 1, which includes a feeding module, a timing module, an input unit and a controller;

the feeding module, the timing module and the input unit are electrically connected with the controller;

the feeding module is used for conveying all reaction materials required for preparing the ternary cathode material precursor into the reaction kettle in a parallel flow mode;

the timing module is used for recording the actual accumulated time of each reaction;

the input unit is used for inputting the preset flow rate of each reaction material of the ternary anode material precursor; the input unit is used for inputting preset integration time of each reaction or preset D50 of a ternary positive electrode material precursor; the input unit is used for inputting the actual D50 of the ternary cathode material precursor;

the controller controls the conveying speed of each reaction material by the feeding module according to the preset accumulated time or the relation between the preset D50 and the preset flow rate and the combination of the actual accumulated time or the actual D50.

Through the automatic control feeding system of the embodiment, when the same kind of ternary cathode materials with the same particle size requirement are produced, a worker can input the preset accumulated time or the preset D50 of each reaction and the preset flow rate of each reaction material into the input unit; the controller automatically controls the conveying speed of the feeding module to each reaction material according to the relation between the preset accumulation time or the preset D50 and the preset flow rate and by combining the actual accumulation time or the actual D50, so that the reaction scale can be increased on the premise of not increasing the number of workers, and the production cost is reduced;

in addition, in the traditional preparation process of the ternary cathode material precursor, because workers need to regulate and control the feeding speed of an alkali solution and an ammonia solution according to the detected reaction pH value and the detected ammonia concentration of a supernatant, and because the pH value of the reaction and the ammonia concentration of the supernatant have the problem of inaccurate detection, the wrong judgment of the workers can be caused, so that the stability of the produced ternary precursors of each batch is poor.

In the whole feeding process, manual operation is not needed, so that the fluctuation and even disqualification of the product quality caused by misoperation are avoided. Meanwhile, due to the high precision of the feeding system and the fact that products of the same type are produced by the same parameters, the stability of the products in different batches can be guaranteed, and the product quality is improved.

The controller of the present embodiment may employ various units that can implement adjustable digital signals, such as various cell machines, microcontrollers, DSPs (digital signal processors), and FPGAs (field programmable gate arrays).

In this embodiment, the controller may adopt a single chip microcomputer, and various control functions may be implemented by programming the single chip microcomputer, for example, in this embodiment, functions such as receiving, determining, and controlling of signals are implemented, and the single chip microcomputer has the advantages of facilitating interface calling and facilitating control.

For example, the controller of the present embodiment may be a PLC automatic controller.

The input unit may be a device for inputting data and information to a computer, and may be, for example, a keyboard for inputting text information.

In particular embodiments, the feed modules include a first feed module, a second feed module, and a third feed module;

the first feeding module is used for conveying the ternary mixed solution into the reaction kettle;

the second feeding module is used for conveying the alkali solution into the reaction kettle;

and the third feeding module is used for conveying the ammonia solution into the reaction kettle.

Because the reaction material of the precursor of the ternary cathode material comprises a ternary mixed solution, an alkaline solution serving as a precipitator and an ammonia solution having a complexing effect, the material module in the embodiment comprises a first material feeding module, a second material feeding module and a third material feeding module;

in this embodiment, the controller may control the flow rate of the ternary mixed solution of the first feeding module, the flow rate of the alkaline solution of the second feeding module, and the flow rate of the ammonia solution of the third feeding module according to the relationship between the preset flow rate and the preset D50 in combination with the actual D50.

The controller can also control the flow rate of the ternary mixed solution of the first feeding module, the flow rate of the alkali solution of the second feeding module and the flow rate of the ammonia solution of the third feeding module according to the relationship between the preset flow rate and the preset accumulated time and by combining the actual accumulated time.

In a specific embodiment, the system further comprises a mass flowmeter for monitoring the flow rate of the feeding module and a frequency converter for regulating and controlling the flow of the feeding module; the mass flow meter is arranged on the feeding module and is electrically connected with the controller; the feeding module is electrically connected with the controller through the frequency converter.

The mass flow meter feeds the detected flow rate back to the controller in real time, and when the actual flow rate is not within the set flow rate range, the controller controls the frequency converter to further change the flow of the feeding module, and finally the flow rate of the feeding module is recovered to the set range.

In a specific embodiment, the device further comprises a temperature detection module, wherein the temperature detection module is electrically connected with the controller;

the temperature detection module is used for detecting the temperature in the reaction kettle and sending the result to the controller;

because the temperature has a large influence on the reaction in the specific production process, the reaction temperature in the reaction process can be monitored at any time through the temperature detection module, and when the temperature is lower than the reaction temperature, the controller can control the steam valve to be opened, the cooling water valve to be closed, and steam is introduced into the interlayer of the reaction kettle to raise the temperature; when the temperature is higher than the reaction temperature, the controller controls the steam valve to be closed, the cooling water valve is opened, cooling water is introduced into the reaction kettle interlayer, and the reaction temperature is reduced. In this embodiment, the temperature detecting module may be a temperature sensor, which is electrically connected to the controller.

In a specific embodiment, the device comprises a display module, the display module is electrically connected with the controller, and the display is used for displaying the actual flow rate of each reaction material, information input by a worker in the input unit and the like, so that the worker can conveniently check the information.

In a specific embodiment, including the pH detection module who is used for detecting pH in the reation kettle, pH detection module and controller electric connection, pH can the pH in the on-line measuring reation kettle, and the controller controls the alarm autoalarm when the big amplitude fluctuation appears suddenly, avoids appearing the quality accident.

In a particular embodiment, the feed module is a metering pump.

In a particular embodiment, the actual flow rate of the metering pump is between 30% and 100% of the rated flow rate of said metering pump, in order to ensure the stability of the feed.

The following is further illustrated with reference to specific production processes:

example 1

The method for preparing the ternary cathode material precursor NCM811 by a continuous method has an automatic control feeding system, and comprises the following steps:

and 1, selecting a proper metering pump and a proper reaction kettle according to the production capacity and experience. This example selects 10m³The maximum flow of the first feeding module (the first metering pump) is 15L/min, the maximum flow of the second feeding module (the second metering pump) is 6L/min, and the maximum flow of the third feeding module (the third metering pump) is 3L/min;

step 2, electrically connecting the first metering pump, the second metering pump and the third metering pump with a controller through frequency converters, and simultaneously installing mass flow meters on feeding pipelines of the first metering pump, the second metering pump and the third metering pump, wherein the mass flow meters and the frequency converters are electrically connected with the controller;

simultaneously adding a base solution into the reaction kettle, wherein the base solution comprises 500kg of water, 100kg of sodium hydroxide solution and 300kg of ammonia water;

and 3, firstly, inputting preset flow rates of all reaction materials of the ternary positive electrode material precursor, namely the preset flow rate of the ternary mixed solution, the preset flow rate of the alkali solution and the preset flow rate of the ammonia solution through an input unit (keyboard) as shown in fig. 2, wherein the stirring frequency is set to be 31 Hz.

Simultaneously inputting preset D50 of the precursor of the ternary cathode material, wherein the preset D50 in the embodiment comprises three preset D50 which are respectively 8 microns, 9 microns and 11 microns;

then, an actual D50 of less than 8 μm was input through the input unit (keyboard), at which time the controller controls the first feeding module to feed the ternary mixed solution into the reaction tank containing the base solution at a flow rate of 600kg/h, controls the second feeding module to feed the alkali solution into the reaction tank containing the base solution at a flow rate of 214kg/h, and controls the third feeding module to feed the ammonia solution into the reaction tank containing the base solution at a flow rate of 62 kg/h;

secondly, sampling and testing the particle size distribution of the product every 2h of reaction, inputting the detected D50 serving as actual D50 through an input unit (keyboard), and automatically controlling the flow rate of each material by a controller according to the input actual D50;

for example, when the input actual D50 satisfies: when D50 is more than 8 mu m and less than 9 mu m, the controller controls the first feeding module to convey the ternary mixed solution into the reaction kettle containing the base solution at the flow rate of 600kg/h, controls the second feeding module to convey the alkali solution into the reaction kettle containing the base solution at the flow rate of 218kg/h, and controls the third feeding module to convey the ammonia solution into the reaction kettle containing the base solution at the flow rate of 60 kg/h;

when the input actual D50 satisfies: when D50 is more than 9 mu m and less than 11 mu m, the controller controls the first feeding module to convey the ternary mixed solution into the reaction kettle containing the base solution at the flow rate of 600kg/h, controls the second feeding module to convey the alkali solution into the reaction kettle containing the base solution at the flow rate of 220kg/h, and controls the third feeding module to convey the ammonia solution into the reaction kettle containing the base solution at the flow rate of 59 kg/h;

when the input actual D50 satisfies: when D50 is more than 11 mu m, the controller controls the first feeding module to convey the ternary mixed solution into the reaction kettle containing the base solution at the flow rate of 600kg/h, controls the second feeding module to convey the alkali solution into the reaction kettle containing the base solution at the flow rate of 226kg/h, and controls the third feeding module to convey the ammonia solution into the reaction kettle containing the base solution at the flow rate of 54 kg/h;

when D50 reached 9um, the overflow material began to be finished. And finally, after the reaction lasts for 300h, stopping feeding, and obtaining a ternary cathode material precursor NCM811 after the procedures of washing, drying, mixing, screening, deironing, packaging and the like.

In order to ensure the accuracy of the reaction, the reaction temperature and the reaction pH in the reaction kettle are detected in real time, namely, the temperature detection module and the pH detection module are electrically connected with the controller and are displayed through the display screen. The temperature detection module of this embodiment is temperature sensor, and the pH detection module is the pH meter.

To verify whether the product obtained by the automatic controlled feeding system of this example is stable, the process of example 1 was repeated three times, and the results are reported as batch 1-1, batch 1-2 and batch 1-3, respectively, and are shown in table 1; as can be seen from table 1, the D50, Tap Density (TD) and specific surface area of each batch of product do not differ much, indicating that the stability of the precursor prepared by this example 1 is better.

Wherein the specific surface area is measured by a BET method.

TABLE 1 batches of product obtained using the feed procedure of example 1

And meanwhile, randomly sampling the products obtained from the batch 1-1, and taking a picture by a scanning electron microscope, wherein the result is shown in figure 4, and the figure 4 shows that the precursor has uniform particle size and a spherical structure.

Comparative example 1

The comparative example adopts the traditional method of manually adjusting the feeding to feed and produce the precursor NCM811 of the ternary cathode material.

Firstly, 400L of pure water is added into a reaction kettle, the PH of a base solution is adjusted to 11.7 by using liquid caustic soda and ammonia water, the ammonia concentration is adjusted to 16g/L, and 2m of nitrogen is introduced³The protection is carried out in the way that the temperature range of the reaction kettle is set to be 69 ℃, and the rotating speed is set to be 300rpm.

480L/h of ternary liquid, 163L/h of liquid caustic soda and 65L/h of ammonia water are fed, sampling is carried out every 0.5h after the start-up for detecting the pH and the particle size distribution, and supernatant liquid is taken for titrating the ammonia-soda concentration. After 4h, samples were taken every 1h for pH measurement, the supernatant was titrated for ammonia-base concentration, and samples were taken every 2h for particle size distribution. In order to prevent the pH meter from generating problems to cause misjudgment, two pH meters are adopted for simultaneous detection, the difference value of the two pH meters is stable, the result is proved to be more reliable, and if the difference value fluctuates, the pH meters are corrected in time. Meanwhile, the pH test should be carried out in a water bath kettle, and the pH is tested at 60 ℃. The sampling quantity and the electrode insertion depth should be kept as consistent as possible.

And adjusting the flow rates of the liquid caustic soda and the ammonia water to the process range. When the D50 is less than 8um, the pH is controlled to be 11.6-11.8, and the ammonia concentration of the supernatant is controlled to be 15-17 g/L; when 8um is less than D50 and less than 9um, the pH is controlled to be 11.7-11.9, and the ammonia concentration of the supernatant is controlled to be 14-16 g/L; when the concentration of 9um is less than D50 and less than 11um, the pH is controlled to be 11.9-12.0, and the ammonia concentration of the supernatant is controlled to be 13-15 g/L; when D50 is larger than 11um, the pH value is controlled to be 12.0-12.1, and the ammonia concentration of the supernatant is controlled to be 12-14 g/L.

When D50 reached 9um, the overflow material began to be finished. And finally, after the reaction lasts for 300h, stopping feeding, and obtaining a ternary cathode material precursor NCM811 after the procedures of washing, drying, mixing, screening, deironing, packaging and the like.

To verify the stability of the product obtained by the manual feeding method of this comparative example, the procedure of comparative example 1 was repeated three times, and the results are shown in table 2, as lots 1-1 ', lots 1-2 ', and lots 1-3 ', respectively; as can be seen from table 2, there are certain differences in D50, Tap Density (TD) and specific surface area for each batch of product, and it is clear that the product of example 1 is more stable than the data in table 1.

Wherein the specific surface area is measured by a BET method.

TABLE 2 batches of product obtained using the feed procedure of comparative example 1

Example 2

The ternary cathode material precursor NCM712 is prepared by a batch method, and an automatic control feeding system comprises the following steps:

and 1, selecting a proper metering pump and a proper reaction kettle according to the production capacity and experience. This example selects 12m³The maximum flow of the first feeding module (first metering pump) is 18L/min, and the second feeding module (second metering pump) is used for feedingThe maximum flow of the material module (second metering pump) is 7.5L/min, and the maximum flow of the third feeding module (third metering pump) is 4L/min;

step 2, electrically connecting the first metering pump, the second metering pump and the third metering pump with a controller through frequency converters, and simultaneously installing mass flow meters on feeding pipelines of the first metering pump, the second metering pump and the third metering pump, wherein the mass flow meters and the frequency converters are electrically connected with the controller;

simultaneously adding a base solution into the reaction kettle, wherein the base solution comprises 400kg of water, 100kg of sodium hydroxide solution and 200kg of ammonia water; introducing nitrogen gas for 2m³The temperature range of the reaction kettle is set to be 62 ℃ under the protection of/h.

Step 3, firstly, as shown in fig. 3, inputting a preset flow rate of each reaction material of the ternary positive electrode material precursor, namely a preset flow rate of the ternary mixed solution, a preset flow rate of the alkali solution and a preset flow rate of the ammonia solution, through an input unit (keyboard);

inputting preset accumulation time in the reaction process of the ternary cathode material precursor, wherein the preset accumulation time in the embodiment includes three times, namely 10h, 40h and 80 h;

then, the controller controls the first feeding module to convey the ternary mixed solution into the reaction kettle containing the base solution at the flow rate of 500kg/h, controls the second feeding module to convey the alkali solution into the reaction kettle containing the base solution at the flow rate of 180kg/h, and controls the third feeding module to convey the ammonia solution into the reaction kettle containing the base solution at the flow rate of 50 kg/h;

the controller controls the feeding module to start feeding, and simultaneously, the timing module (timer) starts timing and sends the accumulated reaction time to the controller in real time, and when the accumulated reaction time received by the controller meets the following requirements: when the accumulated time is more than 10h and less than 40h, the controller controls the first feeding module to convey the ternary mixed solution into the reaction kettle containing the base solution at the flow rate of 500kg/h, controls the second feeding module to convey the alkali solution into the reaction kettle containing the base solution at the flow rate of 175kg/h, and controls the third feeding module to convey the ammonia solution into the reaction kettle containing the base solution at the flow rate of 50 kg/h;

when the accumulated reaction time received by the controller satisfies: when the accumulated time is more than 40h and less than 80h, the controller controls the first feeding module to convey the ternary mixed solution into the reaction kettle containing the base solution at the flow rate of 500kg/h, controls the second feeding module to convey the alkali solution into the reaction kettle containing the base solution at the flow rate of 173kg/h, and controls the third feeding module to convey the ammonia solution into the reaction kettle containing the base solution at the flow rate of 50 kg/h;

when the accumulated reaction time received by the controller satisfies: when the accumulated time is more than 80 hours, the controller controls the first feeding module to convey the ternary mixed solution into the reaction kettle containing the base solution at the flow rate of 500kg/h, controls the second feeding module to convey the alkali solution into the reaction kettle containing the base solution at the flow rate of 171kg/h, and controls the third feeding module to convey the ammonia solution into the reaction kettle containing the base solution at the flow rate of 50 kg/h;

and finally, sampling every 4h in the reaction process to detect the particle size distribution, and controlling the feeding module to stop feeding by the controller until the detected D50 reaches 4.0 mu m to obtain the ternary cathode material precursor NCM 712.

To verify whether the product obtained by the automatic controlled feeding system of this example is stable, the process of example 2 was repeated three times, and the results are reported as batch 2-1, batch 2-2 and batch 2-3, respectively, and are shown in table 3; as can be seen from table 3, the D50, Tap Density (TD) and specific surface area of each batch of product do not differ much, indicating that the stability of the precursor prepared by this example 1 is better.

Wherein the specific surface area is measured by a BET method.

TABLE 3 batches of product obtained using the feed procedure of example 2

Meanwhile, the products obtained from batch 2-1 are randomly sampled and photographed by a scanning electron microscope, and the result is shown in fig. 5, and as can be seen from fig. 5, the particle size of the precursor is uniform and the shape is a spherical structure.

Comparative example 2

The comparative example adopts the traditional method of manually adjusting the feeding to feed and produce the ternary cathode material precursor NCM 712.

Firstly, 400L of pure water is added into a reaction kettle, the PH of a base solution is adjusted to 12.1 by using liquid caustic soda and ammonia water, the ammonia concentration is adjusted to 9g/L, nitrogen is introduced for 2m³The temperature range of the reaction kettle is set to be 62 ℃ under the protection of/h. The start-up speed was set to 500 rpm.

Feeding the ternary solution with the flow rate of 400L/h, the liquid caustic soda with the flow rate of 135L/h and the ammonia water with the flow rate of 55L/h, sampling every 0.5h after starting up for detecting the pH and the particle size distribution within 4h, and taking the supernatant for titrating the ammonia-soda concentration. After 4h, samples were taken every 1h for pH measurement, the supernatant was titrated for ammonia-base concentration, and samples were taken every 4h for particle size distribution. In order to prevent the pH meter from generating problems to cause misjudgment, two pH meters are adopted for simultaneous detection, the difference value of the two pH meters is stable, the result is proved to be more reliable, and if the difference value fluctuates, the pH meters are corrected in time. Meanwhile, the pH test should be carried out in a water bath kettle, and the pH is tested at 60 ℃. The sampling quantity and the electrode insertion depth should be kept as consistent as possible.

The reaction pH is kept between 12.0 and 12.2 within 10 hours after starting up, between 11.8 and 12.0 within 10 hours and between 11.6 and 11.8 within 40 hours and 80 hours, and between 11.4 and 11.6 after 80 hours. The ammonia concentration of the supernatant is always maintained at 8-10 g/L. And in the reaction process, the flow rates of the liquid caustic soda and the ammonia water are adjusted to keep the pH value and the ammonia concentration of the supernatant in a process range. During the period, if the pH and the ammonia-soda concentration exceed the expected values, whether the measurement is a false measurement or not needs to be judged according to the growth trend, if the D50 is increased too fast, the pH is probably lower, and the ammonia concentration is probably higher; if D50 increases too slowly, it may be that the pH is higher and the ammonia concentration is lower. And if the flow rate is judged to be beyond the test range, changing the flow rate of the liquid caustic soda or the flow rate of the ammonia water for adjustment. Meanwhile, as the solid content of the batch method is continuously increased, the stirring current may exceed the standard, the stirring current needs to be concerned at any time, and the rotating speed is reduced after the stirring current exceeds the standard.

Feed was stopped after D50 reached 4.0 um. And washing, drying, screening and removing iron to obtain the NCM712 ternary precursor finished product.

To verify the stability of the product obtained by the manual feeding method of this comparative example, the manual feeding process of comparative example 2 was repeated three times, respectively designated as lots 2-1 ', lots 2-2 ', and lots 2-3 ', and the results are shown in table 4; as can be seen from table 4, there are certain differences in D50, Tap Density (TD) and specific surface area for each batch of product, and it is clear that the product of example 2 is more stable than the data in table 3.

TABLE 4 batches of product obtained using the feed procedure of comparative example 2

In conclusion, the ternary cathode material precursor is produced by the automatic control feeding system for the ternary cathode material precursor, so that the obtained product has better stability, the labor is saved, and the production cost is reduced.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.