Synthesis device and synthesis method of cobalt carbonate

Abstract

The invention belongs to the technical field of battery positive electrode materials, and relates to a synthesis device and a synthesis method of cobalt carbonate, the synthesis device comprises a first-stage reaction kettle, a second-stage reaction kettle, a first-stage thickener and a second-stage thickener which are sequentially connected along the material flow direction; the discharge hole of the first-stage reaction kettle is communicated with the feed hole of the second-stage reaction kettle through an overflow pipeline; a discharge hole of the second-stage reaction kettle is communicated with a feed hole of the first-stage thickener through an overflow pipeline; an overflow outlet of the first-stage thickener is communicated with a feeding hole of the second-stage thickener; and an overflow outlet of the second-stage thickener is communicated with a reflux inlet of the first-stage reaction kettle through a reflux pipeline. The synthesis device provided by the invention can realize continuous and efficient production, can adapt to synthesis of large-particle-size cobalt carbonate, and improves the stability of the product reaction process, the operation efficiency and the product quality.

Description

Technical Field

[0001] This invention belongs to the field of battery cathode material technology, and relates to a cobalt carbonate synthesis apparatus and synthesis method. Background Technology

[0002] Currently, the lithium-ion battery industry in the 3C digital field is developing rapidly. Lithium cobalt oxide, due to its high discharge capacity, good voltage stability, and relatively ideal cycle life, has become a key cathode material for manufacturing lithium-ion rechargeable batteries, basically meeting the target requirements of current mainstream digital products. However, as terminal electronic products continue to develop towards lightweight and long battery life, higher standards are being set for battery energy density, which necessitates further improvements in the performance of lithium cobalt oxide cathode materials.

[0003] As a key precursor for the preparation of lithium cobalt oxide, the performance of cobalt tetroxide directly affects the electrochemical performance of the cathode material. In recent years, to meet the development needs of high-voltage lithium cobalt oxide, large-particle-size, high-density, and structurally stable cobalt carbonate precursors have gradually become the focus of market attention. However, existing production technologies and equipment face challenges in balancing capacity and stability, as well as high process complexity, when dealing with the market demand for high-voltage, large-particle cobalt carbonate.

[0004] In the industrial production of cobalt carbonate, single-reactor synthesis is currently a relatively mature technology. This process achieves the gradual growth of cobalt carbonate particles through repeated settling or thickener purging, and is effective for preparing conventional granular cobalt carbonate suitable for lower voltage conditions. However, with the increasing market demand for high-voltage, large-particle cobalt carbonate, the single-reactor synthesis process has shown certain limitations. The synthesis of large-particle cobalt carbonate requires slow, controlled conditions and a lengthy reaction process. The repeated settling and thickener purging operations in the single-reactor system are prone to equipment failure during long-term operation, leading to significant fluctuations in the synthesis process. Furthermore, single-reactor synthesis is essentially an intermittent operation, requiring frequent cycles of feeding, reaction, discharging, and cleaning, making continuous production impossible, and resulting in significant batch-to-batch product quality variations.

[0005] Therefore, there is an urgent need to develop a device that can achieve continuous and efficient production and is suitable for the synthesis of large-particle-size cobalt carbonate. Summary of the Invention

[0006] In view of the shortcomings of the existing technology, the purpose of this invention is to provide a synthesis apparatus and method for cobalt carbonate. The synthesis apparatus can achieve continuous and efficient production and can adapt to the synthesis of large-particle-size cobalt carbonate, thereby improving the stability of the product reaction process.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides an apparatus for synthesizing cobalt carbonate, the apparatus comprising a primary reactor, a secondary reactor, a primary concentrator, and a secondary concentrator connected sequentially along the material flow direction;

[0009] The discharge port of the primary reactor is connected to the inlet of the secondary reactor via an overflow pipe; the discharge port of the secondary reactor is connected to the inlet of the primary concentrator via an overflow pipe; the overflow outlet of the primary concentrator is connected to the inlet of the secondary concentrator; and the overflow outlet of the secondary concentrator is connected to the reflux port of the primary reactor via a reflux pipe.

[0010] The cobalt carbonate synthesis apparatus provided by this invention is designed as a multi-stage synthesis apparatus. By separating the nucleation and growth stages into different reaction units, it can provide an optimized reaction environment for each stage, thereby achieving precise control over the crystallization process of large-particle cobalt carbonate. At the same time, the synthesis apparatus can react continuously, eliminating the need for operations such as batching due to high solid content or untimely thickener rinsing during the reaction process, thus improving the stability of the product reaction process, operational efficiency, and product quality.

[0011] Preferably, the bottom of the primary and secondary concentrators are each independently provided with a mother liquor discharge port.

[0012] Secondly, the present invention provides a method for synthesizing cobalt carbonate, the synthesis method being carried out using the cobalt carbonate synthesis apparatus described in the first aspect, the synthesis method comprising the following steps:

[0013] (1) Seed nucleation stage: Add the bottom liquid to the primary reactor, then add ammonium bicarbonate solution and cobalt sulfate solution to react until the particle size D50 reaches 6-8 μm, then overflow to the secondary reactor;

[0014] (2) Finished product growth stage: continue to add ammonium bicarbonate solution and cobalt sulfate solution to the reaction system in the secondary reactor, and control particle growth by periodically adjusting the material flow rate. The reaction mother liquor overflows to the primary and secondary thickeners for solid-liquid separation and recovery. The reaction continues until the cobalt carbonate particle size D50 grows to 20-24μm and then the feeding stops.

[0015] The present invention controls the synthesis stage into a seed nucleation stage and a finished product growth stage, which are carried out in different reactors. This provides different reaction environments for crystal nucleation and particle growth, improving product uniformity. At the same time, by independently adjusting key parameters such as temperature, reaction time, and feed flow rate of each reactor, precise control of the large-particle cobalt carbonate crystallization process can be achieved.

[0016] The particle size D50 in step (1) reaches 6-8 μm, for example, it can be 6 μm, 6.5 μm, 7 μm, 7.5 μm or 8 μm, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0017] In step (2), the cobalt carbonate particles D50 are grown to 20-24 μm, for example, 20 μm, 21 μm, 22 μm, 23 μm or 24 μm, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0018] Preferably, the base liquid in step (1) comprises pure water and ammonium bicarbonate solution added sequentially.

[0019] Preferably, the amount of pure water added is 3-5 ml. 3 For example, it could be 3m 3 3.5m 3 4m 3 4.5m 3 or 5m 3 However, this does not limit the listed values; other unlisted values ​​within the range are also applicable.

[0020] Preferably, the amount of ammonium bicarbonate solution added is 200-400L, for example, 200L, 250L, 300L, 350L or 400L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0021] Preferably, the concentration of the ammonium bicarbonate solution is 200-280 g / L, for example, it can be 200 g / L, 220 g / L, 240 g / L, 260 g / L or 280 g / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0022] Preferably, in step (1), after adding the base liquid and before adding the ammonium bicarbonate solution and cobalt sulfate solution, the base liquid is heated to 40-45°C, and the stirring rate of the primary reactor is adjusted to 150-300 r / min.

[0023] The bottom liquid is heated to 40-45°C, for example, 40°C, 41°C, 42°C, 43°C or 45°C, but not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0024] The stirring rate of the primary reactor is adjusted to 150-300 r / min, for example, it can be 150 r / min, 180 r / min, 200 r / min, 250 r / min or 300 r / min, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0025] Preferably, the feed flow rate of the cobalt sulfate solution in step (1) is 200-400 L / h, and the feed flow rate of the ammonium bicarbonate solution is 400-800 L / h.

[0026] The feed flow rate of the cobalt sulfate solution is 200-400 L / h, for example, it can be 200 L / h, 250 L / h, 300 L / h, 350 L / h or 400 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0027] The feed flow rate of the ammonium bicarbonate solution is 400-800 L / h, for example, it can be 400 L / h, 500 L / h, 600 L / h, 700 L / h or 800 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0028] Preferably, the concentration of the ammonium bicarbonate solution in step (1) is 200-280 g / L, for example, it can be 200 g / L, 220 g / L, 240 g / L, 260 g / L or 280 g / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0029] Preferably, the concentration of the cobalt sulfate solution in step (1) is 100-150 g / L, for example, it can be 100 g / L, 110 g / L, 120 g / L, 130 g / L, 140 g / L or 150 g / L, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0030] Preferably, in the secondary reactor of step (2), the feed flow rate of ammonium bicarbonate solution is 400-800 L / h, and the feed flow rate of cobalt sulfate solution is 200-400 L / h.

[0031] The feed flow rate of the ammonium bicarbonate solution is 400-800 L / h, for example, it can be 400 L / h, 500 L / h, 600 L / h, 700 L / h or 800 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0032] The feed flow rate of the cobalt sulfate solution is 200-400 L / h, for example, it can be 200 L / h, 250 L / h, 300 L / h, 350 L / h or 400 L / h, but is not limited to the listed values. Other unlisted values ​​within the range are also applicable.

[0033] Preferably, the periodic adjustment of material flow rate in step (2) is to adjust the feed flow rate of ammonium bicarbonate solution and the feed flow rate of cobalt sulfate solution every 18 hours.

[0034] It should be noted that the present invention does not specifically limit the adjustment range of the feed flow rate of ammonium bicarbonate solution and cobalt sulfate solution. During the finished product growth stage, those skilled in the art can increase or decrease the feed flow rate of ammonium bicarbonate solution and cobalt sulfate solution according to the particle growth situation.

[0035] Preferably, the excess mother liquor in the primary and secondary concentrators in step (2) is discharged.

[0036] In the finished product growth stage described in step (2), the slurry overflowing from the secondary reactor enters the primary thickener for preliminary concentration. The underflow after concentration is discharged and collected. The overflow liquid enters the secondary thickener for further sedimentation. The overflow liquid of the secondary thickener is returned to the primary reactor as a supplement to the underflow liquid. The mother liquor outlets at the bottom of the primary and secondary thickeners periodically discharge excess mother liquor to maintain system balance.

[0037] The numerical range described in this invention includes not only the point values ​​listed above, but also any point values ​​within the numerical ranges not listed above. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific point values ​​included in the range.

[0038] Compared with the prior art, the present invention has the following beneficial effects:

[0039] The cobalt carbonate synthesis apparatus provided by this invention is designed as a multi-stage synthesis apparatus. By separating the nucleation and growth stages into different reaction units, it can provide an optimized reaction environment for each stage, thereby achieving precise control over the crystallization process of large-particle cobalt carbonate. At the same time, the synthesis apparatus can react continuously, eliminating the need for operations such as batching due to high solid content or untimely thickener rinsing during the reaction process, thus improving the stability of the product reaction process, operational efficiency, and product quality.

[0040] The present invention controls the synthesis stage into a seed nucleation stage and a finished product growth stage, which are carried out in different reactors. This provides different reaction environments for crystal nucleation and particle growth, improving product uniformity. At the same time, by independently adjusting key parameters such as temperature, reaction time, and feed flow rate of each reactor, precise control of the large-particle cobalt carbonate crystallization process can be achieved. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the cobalt carbonate synthesis apparatus provided in Embodiment 1 of the present invention.

[0042] Among them: 1, primary reactor; 2, secondary reactor; 3, primary concentrator; 4, secondary concentrator. Detailed Implementation

[0043] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0044] Example 1

[0045] This embodiment provides an apparatus for synthesizing cobalt carbonate, the structural schematic diagram of which is shown below. Figure 1 As shown, the synthesis apparatus includes a primary reactor 1, a secondary reactor 2, a primary concentrator 3, and a secondary concentrator 4 connected sequentially along the material flow direction; the outlet of the primary reactor 1 is connected to the inlet of the secondary reactor 2 via an overflow pipe; the outlet of the secondary reactor 2 is connected to the inlet of the primary concentrator 3 via an overflow pipe; the overflow outlet of the primary concentrator 3 is connected to the inlet of the secondary concentrator 4; the overflow outlet of the secondary concentrator 4 is connected to the reflux outlet of the primary reactor 1 via a reflux pipe; and the bottoms of the primary concentrator 3 and the secondary concentrator 4 are each independently provided with a mother liquor discharge outlet.

[0046] The synthesis of cobalt carbonate using the aforementioned synthesis apparatus comprises the following steps:

[0047] (1) Seed nucleation stage: Add 4m to the primary reactor 1 3 Pure water was added, followed by 300L of ammonium bicarbonate solution with a concentration of 240g / L. The mixture was heated to 42℃, and the stirring speed of the primary reactor 1 was adjusted to 200r / min. Subsequently, ammonium bicarbonate solution and cobalt sulfate solution were added, with the feed flow rate of cobalt sulfate solution controlled at 300L / h, the concentration of cobalt sulfate solution at 130g / L, and the feed flow rate of ammonium bicarbonate solution at 600L / h. The reaction was carried out until the particle size D50 reached 7μm, and then the mixture overflowed into the secondary reactor 2.

[0048] (2) Finished product growth stage: Ammonium bicarbonate solution and cobalt sulfate solution are added to the reaction system in the secondary reactor 2. The feed flow rate of ammonium bicarbonate solution is 600 L / h and the feed flow rate of cobalt sulfate solution is 300 L / h. The feed flow rate of ammonium bicarbonate solution and cobalt sulfate solution is adjusted every 18 hours to control particle growth. The reaction mother liquor overflows to the primary thickener 3 and the secondary thickener 4 for filtration and recovery. The excess mother liquor in the primary thickener 3 and the secondary thickener 4 is discharged. The reaction continues until the cobalt carbonate particle size D50 grows to 22 μm and then the feeding is stopped.

[0049] The synthesis apparatus provided in this embodiment can realize the continuous production of cobalt carbonate, and the production efficiency is increased by 30% compared with the single-reactor synthesis process.

[0050] Example 2

[0051] This embodiment provides a cobalt carbonate synthesis apparatus, which includes a primary reactor 1, a secondary reactor 2, a primary concentrator 3, and a secondary concentrator 4 connected sequentially along the material flow direction; the outlet of the primary reactor 1 is connected to the inlet of the secondary reactor 2 through an overflow pipe; the outlet of the secondary reactor 2 is connected to the inlet of the primary concentrator 3 through an overflow pipe; the overflow outlet of the primary concentrator 3 is connected to the inlet of the secondary concentrator 4; the overflow outlet of the secondary concentrator 4 is connected to the reflux outlet of the primary reactor 1 through a reflux pipe; and the bottom of the primary concentrator 3 and the secondary concentrator 4 are each independently provided with a mother liquor discharge outlet.

[0052] The synthesis of cobalt carbonate using the aforementioned synthesis apparatus comprises the following steps:

[0053] (1) Seed nucleation stage: Add 3m to the primary reactor 1 3 Pure water was added, followed by 400L of ammonium bicarbonate solution with a concentration of 200g / L. The mixture was heated to 40℃, and the stirring speed of the primary reactor 1 was adjusted to 150r / min. Subsequently, ammonium bicarbonate solution and cobalt sulfate solution were added, with the feed flow rate of cobalt sulfate solution controlled at 200L / h, the concentration of cobalt sulfate solution at 150g / L, and the feed flow rate of ammonium bicarbonate solution at 400L / h. The reaction was carried out until the particle size D50 reached 6μm, and then the mixture overflowed into the secondary reactor 2.

[0054] (2) Finished product growth stage: Ammonium bicarbonate solution and cobalt sulfate solution are added to the reaction system in the secondary reactor 2. The feed flow rate of ammonium bicarbonate solution is 400 L / h and the feed flow rate of cobalt sulfate solution is 200 L / h. The feed flow rate of ammonium bicarbonate solution and cobalt sulfate solution is adjusted every 18 hours to control particle growth. The reaction mother liquor overflows to the primary thickener 3 and the secondary thickener 4 for filtration and recovery. The excess mother liquor in the primary thickener 3 and the secondary thickener 4 is discharged. The reaction continues until the cobalt carbonate particle size D50 grows to 20 μm and then the feeding is stopped.

[0055] The synthesis apparatus provided in this embodiment can realize the continuous production of cobalt carbonate, and the production efficiency is increased by 5% compared with the single-reactor synthesis process.

[0056] Example 3

[0057] This embodiment provides a cobalt carbonate synthesis apparatus, which includes a primary reactor 1, a secondary reactor 2, a primary concentrator 3, and a secondary concentrator 4 connected sequentially along the material flow direction; the outlet of the primary reactor 1 is connected to the inlet of the secondary reactor 2 through an overflow pipe; the outlet of the secondary reactor 2 is connected to the inlet of the primary concentrator 3 through an overflow pipe; the overflow outlet of the primary concentrator 3 is connected to the inlet of the secondary concentrator 4; the overflow outlet of the secondary concentrator 4 is connected to the reflux outlet of the primary reactor 1 through a reflux pipe; and the bottom of the primary concentrator 3 and the secondary concentrator 4 are each independently provided with a mother liquor discharge outlet.

[0058] The synthesis of cobalt carbonate using the aforementioned synthesis apparatus comprises the following steps:

[0059] (1) Seed nucleation stage: Add 5m to the primary reactor 1 3 Pure water was added, followed by 200L of ammonium bicarbonate solution with a concentration of 280g / L. The mixture was heated to 45℃, and the stirring speed of the primary reactor 1 was adjusted to 300r / min. Subsequently, ammonium bicarbonate solution and cobalt sulfate solution were added, with the feed flow rate of cobalt sulfate solution controlled at 400L / h, the concentration of cobalt sulfate solution at 100g / L, and the feed flow rate of ammonium bicarbonate solution at 800L / h. The reaction was carried out until the particle size D50 reached 8μm, and then the mixture overflowed into the secondary reactor 2.

[0060] (2) Finished product growth stage: Ammonium bicarbonate solution and cobalt sulfate solution are added to the reaction system in the secondary reactor 2. The feed flow rate of ammonium bicarbonate solution is 800 L / h and the feed flow rate of cobalt sulfate solution is 400 L / h. The feed flow rate of ammonium bicarbonate solution and cobalt sulfate solution is adjusted every 18 hours to control particle growth. The reaction mother liquor overflows to the primary thickener 3 and the secondary thickener 4 for filtration and recovery. The excess mother liquor in the primary thickener 3 and the secondary thickener 4 is discharged. The reaction continues until the cobalt carbonate particle size D50 grows to 24 μm and then the feeding is stopped.

[0061] The synthesis apparatus provided in this embodiment can realize the continuous production of cobalt carbonate, and the production efficiency is increased by 10% compared with the single-reactor synthesis process.

[0062] Example 4

[0063] This embodiment provides a cobalt carbonate synthesis apparatus. Cobalt carbonate is synthesized using the synthesis apparatus. The method of synthesis differs from that in Embodiment 1 in that the stirring rate of the primary reactor 1 in step (1) is adjusted to 100 r / min. All other aspects are the same as in Embodiment 1.

[0064] In this embodiment, the stirring rate of the primary reactor is too low, which leads to a short reaction cycle, a small amount of metal input, and a 20% reduction in production efficiency compared to the single-reactor synthesis process.

[0065] Example 5

[0066] This embodiment provides a cobalt carbonate synthesis apparatus. The synthesis of cobalt carbonate is carried out by the synthesis apparatus. The difference between the synthesis method and that in Embodiment 1 is that the stirring rate of the primary reactor 1 in step (1) is adjusted to 350 r / min. All other aspects are the same as in Embodiment 1.

[0067] In this embodiment, the excessively high stirring rate of the primary reactor leads to an excessively long reaction cycle, an increased amount of metal input, and the need for multiple reactor separations, resulting in a 30% reduction in production efficiency compared to the single-reactor synthesis process.

[0068] Comparative Example 1

[0069] This comparative example provides a cobalt carbonate synthesis apparatus. The difference from Example 1 is that a secondary reactor 2 is not set up. The synthesis method is adapted to carry out the reaction in the primary reactor 1 until the cobalt carbonate particle size D50 grows to 22 μm and then the feeding is stopped. All other aspects are the same as in Example 1.

[0070] Because this comparative example does not have a secondary reactor, the number of reactor separations increases, resulting in a 50% reduction in production efficiency compared to the single-reactor synthesis process.

[0071] Comparative Example 2

[0072] This comparative example provides a cobalt carbonate synthesis apparatus. The difference from Example 1 is that a secondary concentrator 4 is not provided. In the synthesis method, the reaction mother liquor is adapted to overflow to a primary concentrator for filtration and recovery. All other aspects are the same as in Example 1.

[0073] Because this comparative example does not have a secondary concentrator, the reaction cycle is shorter, the amount of metal input is smaller, and the production efficiency is reduced by 60% compared to the single-reactor synthesis process.

[0074] In summary, the synthesis stage of this invention is divided into a seed nucleation stage and a finished product growth stage, which are carried out in different reactors. This provides different reaction environments for crystal nucleation and particle growth, thereby improving product uniformity. At the same time, by independently controlling key parameters such as temperature, reaction time, and feed flow rate of each reactor, precise control of the large-particle-size cobalt carbonate crystallization process can be achieved.

[0075] The above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. An apparatus for synthesizing cobalt carbonate, characterized in that, The synthesis apparatus includes a primary reactor, a secondary reactor, a primary concentrator, and a secondary concentrator connected sequentially along the material flow direction; The discharge port of the primary reactor is connected to the inlet of the secondary reactor via an overflow pipe; the discharge port of the secondary reactor is connected to the inlet of the primary concentrator via an overflow pipe; the overflow outlet of the primary concentrator is connected to the inlet of the secondary concentrator; and the overflow outlet of the secondary concentrator is connected to the reflux port of the primary reactor via a reflux pipe.

2. The synthesis apparatus according to claim 1, characterized in that, The bottom of the primary and secondary concentrators is independently equipped with a mother liquor discharge port.

3. A method for synthesizing cobalt carbonate, characterized in that, The synthesis method is carried out using the cobalt carbonate synthesis apparatus described in claim 1 or 2, and the synthesis method includes the following steps: (1) Seed nucleation stage: Add the bottom liquid to the primary reactor, then add ammonium bicarbonate solution and cobalt sulfate solution to react until the particle size D50 reaches 6-8 μm, then overflow to the secondary reactor; (2) Finished product growth stage: continue to add ammonium bicarbonate solution and cobalt sulfate solution to the reaction system in the secondary reactor, and control particle growth by periodically adjusting the material flow rate. The reaction mother liquor overflows to the primary and secondary thickeners for solid-liquid separation and recovery. The reaction continues until the cobalt carbonate particle size D50 grows to 20-24μm and then the feeding stops.

4. The synthesis method according to claim 3, characterized in that, The base solution in step (1) includes pure water and ammonium bicarbonate solution added sequentially; Preferably, the amount of pure water added is 3-5 ml. 3 ; Preferably, the amount of ammonium bicarbonate solution added is 200-400L; Preferably, the concentration of the ammonium bicarbonate solution is 200-280 g / L.

5. The synthesis method according to claim 3 or 4, characterized in that, In step (1), after adding the base liquid and before adding the ammonium bicarbonate solution and cobalt sulfate solution, the base liquid is heated to 40-45°C, and the stirring rate of the primary reactor is adjusted to 150-300 r / min.

6. The synthesis method according to any one of claims 3-5, characterized in that, The feed flow rate of the cobalt sulfate solution in step (1) is 200-400 L / h, and the feed flow rate of the ammonium bicarbonate solution is 400-800 L / h.

7. The synthesis method according to any one of claims 3-6, characterized in that, The concentration of the ammonium bicarbonate solution in step (1) is 200-280 g / L; Preferably, the concentration of the cobalt sulfate solution in step (1) is 100-150 g / L.

8. The synthesis method according to any one of claims 3-7, characterized in that, In step (2), the feed flow rate of ammonium bicarbonate solution in the secondary reactor is 400-800 L / h, and the feed flow rate of cobalt sulfate solution is 200-400 L / h.

9. The synthesis method according to any one of claims 3-8, characterized in that, The periodic adjustment of material flow rate in step (2) refers to adjusting the feed flow rate of ammonium bicarbonate solution and cobalt sulfate solution every 18 hours.

10. The synthesis method according to any one of claims 3-9, characterized in that, In step (2), the excess mother liquor in the primary and secondary concentrators is discharged.

Images