A device and method for grading and recovering nickel-cobalt hydroxide reaction overflow

Abstract

This invention discloses a graded recovery device and method for nickel-cobalt hydroxide reaction overflow material. The device includes a preparation tank (1), a qualified liquid tank (2), a buffer tank (3), a reaction vessel (4), a thickener (5), a first overflow tank (6), a second overflow tank (7), a filter press (8), and an acid dissolution tank (9). All components are connected via pipes equipped with centrifugal pumps or valves. The recovery method includes the following steps: preparing a binary solution using nickel sulfate, cobalt sulfate, and pure water; storing and replenishing the binary solution; then co-precipitating the binary solution, ammonia, and liquid alkali; material growth; step (four): filtering the material in the first overflow tank and then acid dissolving it to obtain acid-dissolved material; adjusting the concentration of the acid-dissolved material with pure water for later use; returning the material in the second overflow tank to the reaction vessel as bottom material for re-co-precipitation. This invention enables the graded recovery and reuse of nickel-cobalt hydroxide reaction overflow material.

Description

Technical Field

[0001] This invention belongs to the field of nickel-cobalt hydroxide production technology, specifically relating to a graded recovery device and recovery method for nickel-cobalt hydroxide reaction overflow. Background Technology

[0002] The general production process of nickel-cobalt hydroxide is as follows: nickel-cobalt binary solution is prepared by using nickel sulfate solution and cobalt sulfate solution. The nickel-cobalt binary solution, ammonia water and liquid alkali are subjected to co-precipitation reaction. Then, the solution is subjected to pressure filtration, washing, centrifugal dehydration, flash drying, sieving, iron removal and packaging to obtain the finished product.

[0003] The reaction process of some nickel-cobalt hydroxides is carried out in stages. The first stage is the overflow stage, and the second stage is the concentration stage. The overflow material in the overflow stage will become waste. The waste material needs to be filtered by pressure, weighed, and manually fed into the acid dissolution tank for acid dissolution. After the acid dissolution is qualified, it is added in batches into the preparation tank to prepare nickel-cobalt binary solution, and then into the qualified solution tank. This process requires weighing, manual feeding, and mixing, etc., and the recycling process is relatively long. Summary of the Invention

[0004] To address the problems in the prior art, this invention provides a graded recycling device and method for nickel-cobalt hydroxide reaction overflow. This invention enables graded recycling and reuse of nickel-cobalt hydroxide reaction overflow, optimizes the recycling process of reaction overflow, reduces the amount of production waste, improves recycling efficiency, and lowers production costs.

[0005] The present invention adopts the following technical solution:

[0006] A graded recovery device for overflow material from a nickel-cobalt hydroxide reaction is characterized in that the device includes a preparation tank (1), a qualified liquid tank (2), a buffer tank (3), a reaction vessel (4), a thickener (5), a first overflow tank (6), a second overflow tank (7), a filter press (8), and an acid dissolving tank (9). The preparation tank (1) and the qualified liquid tank (2) are connected by a pipe equipped with a centrifugal pump. The qualified liquid tank (2) and the buffer tank (3) are connected by a pipe equipped with a centrifugal pump. The buffer tank (3) and the reaction vessel (4) are connected by a pipe equipped with a centrifugal pump. The first overflow tank (6) is connected to the overflow pipe with a first valve installed. The thickener (5) is connected to the overflow pipe with a second valve installed. The second overflow tank (7) is connected to the overflow pipe with a third valve installed. The second overflow tank (7) is connected to the reactor (4) with a centrifugal pump installed. The first overflow tank (6) is connected to the filter press (8) with a centrifugal pump installed. The filter press (8) is connected to the acid dissolving tank (9) with a valve installed. The acid dissolving tank (9) is connected to the preparation tank (1) with a centrifugal pump installed.

[0007] According to the above-mentioned graded recovery device for nickel-cobalt hydroxide reaction overflow, the top of the preparation tank (1) is characterized by having three material inlets.

[0008] The above-mentioned graded recovery device for nickel-cobalt hydroxide reaction overflow is characterized in that the top of the acid dissolution tank (9) is processed with three material inlets.

[0009] According to the above-mentioned graded recovery device for nickel-cobalt hydroxide reaction overflow, the lower part of the preparation tank (1) is connected to the top of the qualified liquid tank (2) through a pipe equipped with a centrifugal pump; the lower part of the qualified liquid tank (2) is connected to the top of the buffer tank (3) through a pipe equipped with a centrifugal pump; the lower part of the buffer tank (3) is connected to the top of the reactor (4) through a pipe equipped with a centrifugal pump; the upper part of the reactor (4) is connected to the top of the first overflow tank (6) through an overflow pipe equipped with a first valve; and the upper part of the thickener (5) is connected to... The overflow pipe is connected to the pipe with a second valve installed. The top of the second overflow tank (7) is connected to the overflow pipe with a third valve installed. The bottom of the second overflow tank (7) is connected to the top of the reactor (4) with a centrifugal pump installed. The bottom of the first overflow tank (6) is connected to the filter press (8) with a centrifugal pump installed. The bottom of the filter press (8) is connected to the top of the acid dissolving tank (9) with a valve installed. The bottom of the acid dissolving tank (9) is connected to the top of the preparation tank (1) with a centrifugal pump installed.

[0010] According to the above-mentioned graded recovery device for nickel-cobalt hydroxide reaction overflow, the preparation tank (1), qualified liquid tank (2), buffer tank (3), first overflow tank (6), second overflow tank (7), and acid dissolution tank (9) are all equipped with level gauges.

[0011] A recovery method for a graded recovery device based on the above-mentioned nickel-cobalt hydroxide reaction overflow material, characterized in that the recovery method includes the following steps:

[0012] Step (1): Prepare a binary solution by mixing nickel sulfate, cobalt sulfate, and pure water in a mixing tank (1);

[0013] Step (2): The binary liquid is transported to the qualified liquid tank (2) for storage; the binary liquid in the qualified liquid tank (2) is transported to the buffer tank (3) to replenish the liquid level; the binary liquid in the buffer tank (3) is transported to the reaction vessel (4), and then ammonia water and liquid alkali are introduced into the reaction vessel (4) for co-precipitation reaction;

[0014] Step (3): When the particle size D50 of the material in the reactor (4) grows to 3μm-7μm, open the first valve and the material in the reactor (4) overflows into the first overflow tank (6) for storage; when the particle size D50 of the material in the reactor (4) grows to 7μm-10μm, open the third valve and the material in the reactor (4) overflows into the second overflow tank (7) for storage; when the particle size D50 of the material in the reactor (4) grows to 10μm-15μm, open the second valve and the material in the reactor (4) overflows into the thickener (5) for thickening until the particle size D50 of the material in the reactor (4) grows to 14.5μm-15.5μm, then stop feeding into the reactor (4);

[0015] Step (4): The material in the first overflow tank (6) is sent to the filter press (8) for filtration and then enters the acid dissolution tank (9) for acid dissolution to obtain the acid-dissolved material. The acid-dissolved material is sent to the preparation tank (1) and pure water is added to adjust the concentration for later use. The material in the second overflow tank (7) is returned to the reactor (4) as the bottom material and fed back into the reactor (4) for co-precipitation reaction.

[0016] According to the above-mentioned recycling method of the graded recycling device for nickel-cobalt hydroxide reaction overflow, the material particle size D50 stored in the first overflow tank (6) is 3μm-7μm; the material particle size D50 stored in the second overflow tank (7) is 7μm-10μm.

[0017] According to the above-mentioned method for recycling overflow material from nickel-cobalt hydroxide reaction graded recycling device, the characteristic of step (iv) is that the material in the first overflow tank (6) is transported to the filter press (8) for filtration and then enters the acid dissolution tank (9) for acid dissolution as follows: First, pure water is used to slurry the material after filtration in the filter press (8) in the acid dissolution tank (9) to obtain slurry. Then, the solid content of the slurry is detected. Based on the volume and solid content of the slurry, the solid mass in the slurry is obtained. Then, sulfuric acid and sodium sulfite are added to the acid dissolution tank (9) and stirred for 2-4 hours to obtain the acid-dissolved material. The ratio of the solid mass in the slurry, the volume of sulfuric acid, and the mass of sodium sulfite is 1:2.5-3.5:0.012-0.018.

[0018] The beneficial technical effects of this invention are as follows: This invention recycles the overflow material from the nickel-cobalt hydroxide reaction in two stages. The overflow material with larger particle size is returned to the reactor as bottom material for restarting the reaction; the overflow material with smaller particle size is filtered and then enters the acid dissolution tank for acid dissolution, and is then directionally returned to the nickel-cobalt binary solution preparation tank of this model. After adding pure water to adjust the concentration, it can be used. This optimizes the overflow material recovery process. The staged recovery of overflow material can reduce the generation of waste and improve the recovery efficiency. The staged recovery and use of the reaction overflow material can improve the yield, reduce the amount of auxiliary materials used, and reduce production costs. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the structure of the device of the present invention;

[0020] Figure 2 This is a schematic diagram of the process flow of the method of the present invention. Detailed Implementation

[0021] See Figure 1 The present invention discloses a graded recovery device for overflow material from a nickel-cobalt hydroxide reaction, comprising a preparation tank 1, a qualified liquid tank 2, a buffer tank 3, a reaction vessel 4, a thickener 5, a first overflow tank 6, a second overflow tank 7, a filter press 8, and an acid dissolving tank 9. The preparation tank 1 and the qualified liquid tank 2 are connected by a pipe equipped with a centrifugal pump. The qualified liquid tank 2 and the buffer tank 3 are connected by a pipe equipped with a centrifugal pump. The buffer tank 3 and the reaction vessel 4 are connected by a pipe equipped with a centrifugal pump. The reaction vessel 4 and the first overflow tank 6 are connected by an overflow pipe equipped with a first valve. The thickener 5 and the overflow pipe are connected by a pipe equipped with a second valve. The second overflow tank 7 and the overflow pipe are connected by a pipe equipped with a third valve. The second overflow tank 7 and the reaction vessel 4 are connected by a pipe equipped with a centrifugal pump. The first overflow tank 6 and the filter press 8 are connected by a pipe equipped with a centrifugal pump. The filter press 8 and the acid dissolving tank 9 are connected by a pipe equipped with a valve. The acid dissolving tank 9 and the preparation tank 1 are connected by a pipe equipped with a centrifugal pump. The preparation tank 1, qualified liquid tank 2, buffer tank 3, first overflow tank 6, second overflow tank 7, and acid dissolving tank 9 are all equipped with level gauges. The top of the preparation tank 1 has material inlets for nickel sulfate, cobalt sulfate, and pure water. The top of the acid dissolving tank 9 has material inlets for sulfuric acid, sodium sulfite, and pure water. Preferably, the lower part of the preparation tank 1 is connected to the top of the qualified liquid tank 2 via a pipe equipped with a centrifugal pump; the lower part of the qualified liquid tank 2 is connected to the top of the buffer tank 3 via a pipe equipped with a centrifugal pump; the lower part of the buffer tank 3 is connected to the top of the reactor 4 via a pipe equipped with a centrifugal pump; the upper part of the reactor 4 is connected to the top of the first overflow tank 6 via an overflow pipe equipped with a first valve; the upper part of the thickener 5 is connected to the overflow pipe via a pipe equipped with a second valve; the top of the second overflow tank 7 is connected to the overflow pipe via a pipe equipped with a third valve; the lower part of the second overflow tank 7 is connected to the top of the reactor 4 via a pipe equipped with a centrifugal pump; the lower part of the first overflow tank 6 is connected to the filter press 8 via a pipe equipped with a centrifugal pump; the bottom of the filter press 8 is connected to the top of the acid dissolving tank 9 via a pipe equipped with a valve; and the lower part of the acid dissolving tank 9 is connected to the top of the preparation tank 1 via a pipe equipped with a centrifugal pump.

[0022] See Figure 2 The recovery method of the nickel-cobalt hydroxide reaction overflow device of the present invention includes the following steps:

[0023] Step (1): Prepare a binary solution by mixing nickel sulfate, cobalt sulfate, and pure water in preparation tank 1.

[0024] Step (2): The binary liquid is transferred to the qualified liquid tank 2 for storage; the binary liquid in the qualified liquid tank 2 is transferred to the buffer tank 3 to replenish the liquid level; the binary liquid in the buffer tank 3 is transferred to the reaction vessel 4, and then ammonia water and liquid alkali are introduced into the reaction vessel 4 to carry out a co-precipitation reaction.

[0025] Step (3): In the first overflow stage, the particle size D50 of the material in reactor 4 grows to 3μm-7μm. The first valve is opened, and the second and third valves are closed. The material in reactor 4 overflows into the first overflow tank 6 (small particle size overflow tank) for storage; the particle size D50 of the material stored in the first overflow tank 6 is 3μm-7μm. In the second overflow stage, the particle size D50 of the material in reactor 4 grows to 7μm-10μm. The third valve is opened, and the first and second valves are closed. The material in reactor 4 overflows into the second overflow tank 7 for storage; the particle size D50 of the material stored in the second overflow tank 7 (large particle size overflow tank) is 7μm-10μm. During the thickening stage, when the particle size D50 of the material in reactor 4 grows to 10μm-15μm, the second valve is opened and the first and third valves are closed. The material in reactor 4 overflows into thickener 5 for thickening until the particle size D50 of the material in reactor 4 grows to 14.5μm-15.5μm. Then, feeding into reactor 4 is stopped and the stirring frequency in reactor 4 is reduced.

[0026] Step (4): The material in the first overflow tank 6 is conveyed to the filter press 8 for filtration and then enters the acid dissolution tank 9 for acid dissolution to obtain the acid-dissolved material. The acid-dissolved material is then conveyed to the preparation tank 1, pure water is added to adjust the concentration, and then it is conveyed to the qualified liquid tank for storage and use. The material in the second overflow tank 7 is returned to the reaction vessel 4 as the bottom material, and the material is fed back into the reaction vessel 4 for co-precipitation reaction. The stirring frequency in the reaction vessel 4 is increased. The steps for conveying the material in the first overflow tank 6 to the filter press 8 for filtration and then to the acid dissolution tank 9 for acid dissolution are as follows: First, pure water is used to slurry the material filtered in the filter press 8 in the acid dissolution tank 9 to obtain a slurry. Then, the solid content of the slurry is detected. Based on the volume and solid content of the slurry, the mass of solids in the slurry is obtained. Then, sulfuric acid and sodium sulfite are added to the acid dissolution tank 9 and stirred for 2-4 hours to obtain the acid-dissolved material. The ratio of the mass of solids (kg), the volume of sulfuric acid (L), and the mass of sodium sulfite (kg) in the slurry is 1:2.5-3.5:0.012-0.018.

[0027] Example 1

[0028] A binary solution is prepared by mixing nickel sulfate, cobalt sulfate, and pure water in preparation tank 1. The concentration of the binary solution is 120 g / L, and the molar ratio of nickel to cobalt in the binary solution is 9:1.

[0029] The prepared binary solution is transported to the qualified liquid tank 2 for storage; the binary solution in the qualified liquid tank 2 is transported to the buffer tank 3 to replenish the liquid level; the binary solution in the buffer tank 3 is transported to the reaction vessel 4, and then ammonia water and liquid alkali are introduced into the reaction vessel 4 to carry out a co-precipitation reaction.

[0030] The reactor 4 is started. The initial particle size D50 of the material in the reactor 4 is 3-4 μm. During the first overflow stage, the particle size D50 of the material in the reactor 4 grows to 3 μm-7 μm. The first valve is opened, and the second and third valves are closed. The material in the reactor 4 overflows into the first overflow tank 6 for storage. During the second overflow stage, the particle size D50 of the material in the reactor 4 grows to 7 μm-10 μm. The third valve is opened, and the first and second valves are closed. The material in the reactor 4 overflows into the second overflow tank 7 for storage. During the thickening stage, the particle size D50 of the material in the reactor 4 grows to 10 μm-15 μm. The second valve is opened, and the first and third valves are closed. The material in the reactor 4 overflows into the thickener 5 for thickening until the particle size D50 of the material in the reactor 4 grows to 14.5 μm-15.5 μm. Then, feeding into the reactor 4 is stopped, and the stirring frequency in the reactor 4 is reduced.

[0031] The material in the first overflow tank 6 is conveyed to the filter press 8 for filtration and then enters the acid dissolution tank 9 for acid dissolution. The acid-dissolved material is then conveyed to the preparation tank 1, where pure water is added to adjust the concentration and nickel-cobalt molar ratio of the binary solution to meet the requirements. Finally, it is conveyed to the qualified liquid tank for storage and use. The material in the second overflow tank 7 is returned to the reaction vessel 4 as bottom material, and is then fed back into the reaction vessel 4 for co-precipitation reaction. The stirring frequency in the reaction vessel 4 is increased. The acid dissolution process involves: first, slurrying the material filtered in the filter press 8 with pure water to obtain a slurry; then, detecting the solid content of the slurry, which is 150 g / L, and based on the slurry volume of 4 m³... 3 With a solids content of 150 g / L, the slurry contained 600 kg of solids. 1.8 mg of sulfuric acid was added. 3 Add 9 kg of sodium sulfite, stir for 2 hours, take a sample to test the pH value to be 2-4, and directionally recover it into the preparation tank. After adding pure water to adjust the concentration, it is transported to the qualified liquid tank for storage and use.

[0032] Example 2

[0033] A binary solution is prepared by mixing nickel sulfate, cobalt sulfate, and pure water in preparation tank 1. The concentration of the binary solution is 120 g / L, and the molar ratio of nickel to cobalt in the binary solution is 9:1.

[0034] The prepared binary solution is transported to the qualified liquid tank 2 for storage; the binary solution in the qualified liquid tank 2 is transported to the buffer tank 3 to replenish the liquid level; the binary solution in the buffer tank 3 is transported to the reaction vessel 4, and then ammonia water and liquid alkali are introduced into the reaction vessel 4 to carry out a co-precipitation reaction.

[0035] The reactor 4 is started. The initial particle size D50 of the material in the reactor 4 is 3-4 μm. During the first overflow stage, the particle size D50 of the material in the reactor 4 grows to 3 μm-7 μm. The first valve is opened, and the second and third valves are closed. The material in the reactor 4 overflows into the first overflow tank 6 for storage. During the second overflow stage, the particle size D50 of the material in the reactor 4 grows to 7 μm-10 μm. The third valve is opened, and the first and second valves are closed. The material in the reactor 4 overflows into the second overflow tank 7 for storage. During the thickening stage, the particle size D50 of the material in the reactor 4 grows to 10 μm-15 μm. The second valve is opened, and the first and third valves are closed. The material in the reactor 4 overflows into the thickener 5 for thickening until the particle size D50 of the material in the reactor 4 grows to 14.5 μm-15.5 μm. Then, feeding into the reactor 4 is stopped, and the stirring frequency in the reactor 4 is reduced.

[0036] The material in the first overflow tank 6 is conveyed to the filter press 8 for filtration and then enters the acid dissolution tank 9 for acid dissolution. The acid-dissolved material is then conveyed to the preparation tank 1, where pure water is added to adjust the concentration and nickel-cobalt molar ratio of the binary solution to meet the requirements. Finally, it is conveyed to the qualified liquid tank for storage and use. The material in the second overflow tank 7 is returned to the reaction vessel 4 as bottom material, and is then fed back into the reaction vessel 4 for co-precipitation reaction. The stirring frequency in the reaction vessel 4 is increased. The acid dissolution process involves: first, slurrying the material filtered in the filter press 8 with pure water to obtain a slurry; then, detecting that the solid content of the slurry is 200 g / L, and based on the slurry volume of 4 m³... 3 With a solids content of 200 g / L, the slurry contained 800 kg of solids. 2.4 mg of sulfuric acid was added. 3 Add 12 kg of sodium sulfite, stir for 2 hours, take a sample to test the pH value to be 2-4, and directionally recover it into the preparation tank. After adding pure water to adjust the concentration, it is transported to the qualified liquid tank for storage and use.

[0037] Example 3

[0038] A binary solution is prepared by mixing nickel sulfate, cobalt sulfate, and pure water in preparation tank 1. The concentration of the binary solution is 120 g / L, and the molar ratio of nickel to cobalt in the binary solution is 9:1.

[0039] The prepared binary solution is transported to the qualified liquid tank 2 for storage; the binary solution in the qualified liquid tank 2 is transported to the buffer tank 3 to replenish the liquid level; the binary solution in the buffer tank 3 is transported to the reaction vessel 4, and then ammonia water and liquid alkali are introduced into the reaction vessel 4 to carry out a co-precipitation reaction.

[0040] The reactor 4 is started. The initial particle size D50 of the material in the reactor 4 is 3-4 μm. During the first overflow stage, the particle size D50 of the material in the reactor 4 grows to 3 μm-7 μm. The first valve is opened, and the second and third valves are closed. The material in the reactor 4 overflows into the first overflow tank 6 for storage. During the second overflow stage, the particle size D50 of the material in the reactor 4 grows to 7 μm-10 μm. The third valve is opened, and the first and second valves are closed. The material in the reactor 4 overflows into the second overflow tank 7 for storage. During the thickening stage, the particle size D50 of the material in the reactor 4 grows to 10 μm-15 μm. The second valve is opened, and the first and third valves are closed. The material in the reactor 4 overflows into the thickener 5 for thickening until the particle size D50 of the material in the reactor 4 grows to 14.5 μm-15.5 μm. Then, feeding into the reactor 4 is stopped, and the stirring frequency in the reactor 4 is reduced.

[0041] The material in the first overflow tank 6 is conveyed to the filter press 8 for filtration and then enters the acid dissolution tank 9 for acid dissolution. The acid-dissolved material is then conveyed to the preparation tank 1, where pure water is added to adjust the concentration and nickel-cobalt molar ratio of the binary solution to meet the requirements. Finally, it is conveyed to the qualified liquid tank for storage and use. The material in the second overflow tank 7 is returned to the reaction vessel 4 as bottom material, and is then fed back into the reaction vessel 4 for co-precipitation reaction. The stirring frequency in the reaction vessel 4 is increased. The acid dissolution process involves: first, slurrying the material filtered in the filter press 8 with pure water to obtain a slurry; then, detecting the solid content of the slurry, which is 250 g / L, and based on the slurry volume of 4 m³... 3 With a solids content of 250 g / L, the slurry had a solids mass of 1000 kg. 3.0 mg of sulfuric acid was added. 3 Add 15 kg of sodium sulfite, stir for 2-4 hours, take a sample to test the pH value to be 2-4, and then directionally recover it into the preparation tank. After adding pure water to adjust the concentration, it is transported to the qualified liquid tank for storage and use.

Claims

1. A device for fractional recovery of nickel-cobalt hydroxide reaction overflow, characterized in that, The apparatus includes a preparation tank (1), a qualified liquid tank (2), a buffer tank (3), a reaction vessel (4), a thickener (5), a first overflow tank (6), a second overflow tank (7), a filter press (8), and an acid dissolving tank (9). The preparation tank (1) and the qualified liquid tank (2) are connected by a pipe equipped with a centrifugal pump. The qualified liquid tank (2) and the buffer tank (3) are connected by a pipe equipped with a centrifugal pump. The buffer tank (3) and the reaction vessel (4) are connected by a pipe equipped with a centrifugal pump. The reaction vessel (4) and the first overflow tank (6) are connected by a pipe equipped with a centrifugal pump. The first valve is connected to the overflow pipe. The thickener (5) is connected to the overflow pipe through a pipe with a second valve installed. The second overflow tank (7) is connected to the overflow pipe through a pipe with a third valve installed. The second overflow tank (7) is connected to the reactor (4) through a pipe with a centrifugal pump installed. The first overflow tank (6) is connected to the filter press (8) through a pipe with a centrifugal pump installed. The filter press (8) is connected to the acid dissolving tank (9) through a pipe with a valve installed. The acid dissolving tank (9) is connected to the preparation tank (1) through a pipe with a centrifugal pump installed.

2. The device for fractional recovery of nickel-cobalt hydroxide reaction overflow according to claim 1, characterized in that, The top of the preparation tank (1) is machined with three material inlets.

3. The device for fractional recovery of nickel-cobalt hydroxide reaction overflow according to claim 1, characterized in that, The top of the acid dissolving tank (9) has three material inlets.

4. The device for fractional recovery of nickel-cobalt hydroxide reaction overflow according to claim 1, characterized in that, The lower part of the preparation tank (1) is connected to the top of the qualified liquid tank (2) via a pipe equipped with a centrifugal pump. The lower part of the qualified liquid tank (2) is connected to the top of the buffer tank (3) via a pipe equipped with a centrifugal pump. The lower part of the buffer tank (3) is connected to the top of the reactor (4) via a pipe equipped with a centrifugal pump. The upper part of the reactor (4) is connected to the top of the first overflow tank (6) via an overflow pipe equipped with a first valve. The upper part of the thickener (5) is connected to the overflow pipe via a pipe equipped with a second valve. The top of the second overflow tank (7) is connected to the overflow pipe through a pipe with a third valve installed. The bottom of the second overflow tank (7) is connected to the top of the reactor (4) through a pipe with a centrifugal pump installed. The bottom of the first overflow tank (6) is connected to the filter press (8) through a pipe with a centrifugal pump installed. The bottom of the filter press (8) is connected to the top of the acid dissolving tank (9) through a pipe with a valve installed. The bottom of the acid dissolving tank (9) is connected to the top of the preparation tank (1) through a pipe with a centrifugal pump installed.

5. The graded recovery device for nickel-cobalt hydroxide reaction overflow according to claim 1, characterized in that, The preparation tank (1), qualified liquid tank (2), buffer tank (3), first overflow tank (6), second overflow tank (7), and acid dissolution tank (9) are all equipped with level gauges.

6. A method for recovering nickel-cobalt hydroxide reaction overflow material based on the graded recovery device according to any one of claims 1-5, characterized in that, The recycling method includes the following steps: Step (1): Prepare a binary solution by mixing nickel sulfate, cobalt sulfate, and pure water in a mixing tank (1); Step (2): The binary liquid is transported to the qualified liquid tank (2) for storage; the binary liquid in the qualified liquid tank (2) is transported to the buffer tank (3) to replenish the liquid level; the binary liquid in the buffer tank (3) is transported to the reaction vessel (4), and then ammonia water and liquid alkali are introduced into the reaction vessel (4) for co-precipitation reaction; Step (3): When the particle size D50 of the material in the reactor (4) grows to 3μm-7μm, open the first valve and the material in the reactor (4) overflows into the first overflow tank (6) for storage; when the particle size D50 of the material in the reactor (4) grows to 7μm-10μm, open the third valve and the material in the reactor (4) overflows into the second overflow tank (7) for storage; when the particle size D50 of the material in the reactor (4) grows to 10μm-15μm, open the second valve and the material in the reactor (4) overflows into the thickener (5) for thickening until the particle size D50 of the material in the reactor (4) grows to 14.5μm-15.5μm, then stop feeding into the reactor (4); Step (4): The material in the first overflow tank (6) is sent to the filter press (8) for filtration and then enters the acid dissolution tank (9) for acid dissolution to obtain the acid-dissolved material. The acid-dissolved material is sent to the preparation tank (1) and pure water is added to adjust the concentration for later use. The material in the second overflow tank (7) is returned to the reactor (4) as the bottom material and fed back into the reactor (4) for co-precipitation reaction.

7. The recovery method of the graded recovery device for nickel-cobalt hydroxide reaction overflow according to claim 6, characterized in that, The material with a particle size D50 stored in the first overflow tank (6) is 3μm-7μm; the material with a particle size D50 stored in the second overflow tank (7) is 7μm-10μm.

8. The recovery method of the graded recovery device for nickel-cobalt hydroxide reaction overflow according to claim 6, characterized in that, The steps in step (four) of conveying the material in the first overflow tank (6) to the filter press (8) for filtration and then entering the acid dissolution tank (9) for acid dissolution are as follows: First, pure water is used to slurry the material after filtration in the filter press (8) in the acid dissolution tank (9) to obtain slurry. Then, the solid content of the slurry is detected. Based on the volume and solid content of the slurry, the mass of solids in the slurry is obtained. Then, sulfuric acid and sodium sulfite are added to the acid dissolution tank (9) and stirred for 2-4 hours to obtain the acid-dissolved material. The ratio of the mass of solids in the slurry, the volume of sulfuric acid, and the mass of sodium sulfite is 1:2.5-3.5:0.012-0.018.

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