Production device for continuously preparing lithium carbonate from lithium hydroxide

Abstract

The utility model relates to the technical field of lithium carbonate production devices, in particular to a production device for continuously preparing lithium carbonate from lithium hydroxide. The utility model provides a production device for continuously preparing lithium carbonate from lithium hydroxide, the production device comprises a precooler, a reactor, a circulating pump, a centrifugal machine, a mother liquor tank, a mother liquor pump and a plate-and-frame filter press which are sequentially connected through a pipeline, in order to realize continuous production operation of lithium carbonate, the reactor is a continuous reaction device of a four-stage reactor, and the centrifugal machine is a centrifugal machine. The number of the reactors and the number of the circulating pumps are both four, the yield of lithium carbonate is increased through four-stage continuous countercurrent carbonization, the four reactors are divided into a first-stage reactor, a second-stage reactor, a third-stage reactor and a fourth-stage reactor, and the four circulating pumps are divided into a first-stage circulating pump, a second-stage circulating pump, a third-stage circulating pump and a fourth-stage circulating pump. According to the production device disclosed by the invention, a continuous reaction device of a four-stage reactor is designed, so that the yield of lithium carbonate can be increased through four-stage continuous countercurrent carbonization.

Description

Technical Field

[0001] The present application relates to the technical field of lithium carbonate production equipment, and in particular to a production equipment for continuously preparing lithium carbonate from lithium hydroxide. Background Art

[0002] In the prior art, in the lithium carbonate industry, lithium carbonate is produced using the sulfuric acid method, which is widely used in spodumene, lepidolite ore and battery recycling materials; because the lithium sulfate solution is obtained by adding sulfuric acid to remove impurities, the original process is to add sodium carbonate to generate lithium carbonate precipitation, complete the lithium precipitation operation, and obtain the lithium carbonate product.

[0003] Due to the widespread application of ion membrane technology in the lithium industry in recent years, the production of lithium carbonate using the sulfuric acid method can be separated by ion membrane to obtain sulfuric acid solution and lithium hydroxide solution.

[0004] The sulfuric acid solution is returned to the acid addition section for recycling, and the lithium hydroxide solution can also be evaporated and crystallized to obtain lithium hydroxide solid. Because it is a strongly alkaline hazardous chemical and the demand for downstream production of lithium battery positive electrode materials is not large, a considerable portion of it needs to be converted into lithium carbonate products for sale.

[0005] The original production device added lithium hydroxide solution into the reactor and then introduced carbon dioxide gas to react and generate lithium carbonate precipitate. However, this method is an intermittent operation with low production efficiency. In addition, feeding and discharging will cause part of the carbon dioxide to escape and be wasted. During the reaction, material stagnation and pipeline blockage are likely to occur inside the equipment. Utility Model Content

[0006] The problem to be solved by the present application is that the existing lithium carbonate production device is an indirect production device, which not only results in low production efficiency, but also causes carbon dioxide escape loss during material feeding and discharging, and the problem of material stagnation and pipeline blockage easily forming inside the equipment during the reaction process.

[0007] In order to solve the above technical problems, the present application provides a production device for continuously preparing lithium carbonate from lithium hydroxide, which is characterized by comprising a precooler, a reactor, a circulation pump, a carbonized liquid storage tank, a centrifuge, a mother liquid tank, a mother liquid pump and a plate and frame filter press connected in sequence by pipelines, the reactor being a continuous reaction device of a four-stage reactor, the number of reactors and circulation pumps are four groups, the four groups of reactors are divided into a primary reactor, a secondary reactor, a tertiary reactor and a fourth-stage reactor, and the four groups of circulation pumps are divided into a primary circulation pump, a secondary circulation pump, a tertiary circulation pump and a fourth-stage circulation pump.

[0008] Since the production device of the present application is designed as a continuous reaction device with a four-stage reactor, the yield of lithium carbonate can be improved through four-stage continuous countercurrent carbonization, which solves the problem that the lithium carbonate production device in the prior art is an indirect production device, which not only results in low production efficiency, but also causes carbon dioxide escape loss during feeding and discharging, and the problem that material stagnation and pipeline blockage are easily formed inside the equipment during the reaction process. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 It is a structural schematic diagram of an embodiment.

[0010] In the figure: 1. precooler; 2. primary reactor; 3. primary circulation pump; 4. secondary reactor; 5. secondary circulation pump; 6. tertiary reactor; 7. tertiary circulation pump; 8. quaternary reactor; 9. quaternary circulation pump; 10. carbonized liquid storage tank; 11. centrifuge; 12. mother liquid tank; 13. mother liquid pump; 14. plate and frame filter press. DETAILED DESCRIPTION

[0011] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application. Example

[0012] The present application relates to a production device for continuously preparing lithium carbonate from lithium hydroxide, such as Figure 1 As shown, the production device includes a precooler 1, a reactor, a circulation pump, a carbonized liquid storage tank 10, a centrifuge 11, a mother liquid tank 12, a mother liquid pump 13 and a plate and frame filter press 14 which are sequentially connected by pipelines. In order to realize the continuous production operation of lithium carbonate, the reactor is a continuous reaction device of a four-stage reactor 8. The number of reactors and circulation pumps is four groups. Four-stage continuous countercurrent carbonization is adopted to improve the yield of lithium carbonate. The four groups of reactors are divided into a primary reactor 2, a secondary reactor 4, a tertiary reactor 6 and a fourth reactor 8. The four groups of circulation pumps are divided into a primary circulation pump 3, a secondary circulation pump 5, a tertiary circulation pump 7 and a fourth circulation pump 9.

[0013] A lithium hydroxide inlet is provided at the lower left end of the precooler 1, the output end of the precooler 1 is connected to the input end of the primary reactor 2 through a pipeline, the primary circulation pump 3 is respectively connected to the primary reactor 2 and the secondary reactor 4 through pipelines, the secondary circulation pump 5 is respectively connected to the secondary reactor 4 and the tertiary reactor 6 through pipelines, the tertiary circulation pump 7 is respectively connected to the tertiary reactor 6 and the quaternary reactor 8 through pipelines, the quaternary circulation pump 9 is respectively connected to the quaternary reactor 8 and the carbonized liquid storage tank 10 through pipelines, the centrifuge 11 is respectively connected to the carbonized liquid storage tank 10 and the mother liquid tank 12 through pipelines, and the mother liquid pump 13 is respectively connected to the mother liquid tank 12 and the plate and frame filter press 14 through pipelines.

[0014] Solution flow: The lithium hydroxide solution from the lithium hydroxide storage tank is transported by the lithium hydroxide feed pump, cooled by the precooler 1, and then enters the primary reactor 2 to react with carbon dioxide. The primary completed liquid is then transported by the primary circulation pump 3 to the secondary reactor 4 to continue to react with carbon dioxide. The secondary completed liquid is then transported by the secondary circulation pump 5 to the tertiary reactor 6 to continue to react with carbon dioxide. The tertiary completed liquid is then transported by the tertiary circulation pump 7 to the quaternary reactor 8 to continue to react with carbon dioxide. The completed liquid of the quaternary reactor 8 is transported by the quaternary circulation pump 9 to the carbonization liquid storage tank 10 for buffering, and solid-liquid separation is performed by the centrifugal separation equipment. The separated wet lithium carbonate enters the drying and crushing section, and the separated mother liquor enters the mother liquor tank 12. The mother liquor enters the subsequent section after being treated by the plate and frame filter press 14 and the bag filter.

[0015] The bottom of each reactor is equipped with a large-flow circulation pump for internal solution circulation and material discharge to prevent the generated lithium carbonate from accumulating at the bottom of the reactor and causing a dead tower.

[0016] CO2 flow: Liquid CO2 from the liquid CO2 storage tank is vaporized by the vaporizer, and then enters the aeration plate at the bottom of the first, second, third, and fourth reactors through the pressure reducing device, and reacts with the lithium hydroxide solution connected in series with the first, second, third, and fourth reactors 8. The unreacted CO2 gas in the second, third, and fourth reactors 8 enters the aeration plate in the middle of the first reactor 2, and continues to react with the lithium hydroxide solution inside the first reactor 2. The CO2 flow rate is controlled by the pressure of the first reactor 2.

[0017] Circulating cooling water is introduced into the first three-stage reactor 6 to maintain the temperature of the reactor, and steam is introduced into the fourth-stage reactor 8 to increase the temperature of the material, reduce the probability of forming lithium bicarbonate, and at the same time increase the yield of lithium carbonate.

[0018] Thus, the continuous production operation of lithium carbonate can be realized by means of the production device, and almost all carbon dioxide participates in the reaction, which reduces waste and production costs. Moreover, the production of lithium carbonate by the reaction of lithium hydroxide and carbon dioxide has the following characteristics:

[0019] 1. The reaction rate is proportional to the concentration of the raw material. The higher the concentration, the greater the reaction rate.

[0020] 2. The greater the reaction pressure, the faster the reaction rate, but lithium bicarbonate will be generated in the reaction;

[0021] 3. The solubility of carbon dioxide increases with increasing pressure and decreases with increasing temperature;

[0022] 4. The solubility of lithium carbonate decreases with increasing temperature;

[0023] 5. This reaction requires the direct yield of lithium carbonate to be as high as possible.

[0024] Moreover, the device is a continuous reaction device. Compared with the intermittent device, the same equipment size can increase the production capacity by at least 3 times, and after the adjustment is stable, frequent operation is not required, which greatly reduces the labor intensity of on-site production workers. The device is equipped with a carbon dioxide recovery device, which makes the utilization rate of carbon dioxide reach more than 98%, further reducing production consumption; each step is equipped with monitoring instruments and automatic control valves, which can monitor and adjust production parameters in real time to maximize production efficiency.

[0025] Instruments and automatic control valves are set in each process, and automatic continuous production is achieved with the automatic control program to maximize the utilization rate of the equipment; the production process is fully closed to ensure the minimum escape of carbon dioxide, thereby improving the utilization rate of carbon dioxide; after a period of production, some lithium carbonate will form scars, and an automatic cleaning program is set up to automatically clean the equipment with one click, further reducing the intensity of production operations.

[0026] It is to be understood that the present application is described by some embodiments, and it is known to those skilled in the art that various changes or equivalent substitutions may be made to these features and embodiments without departing from the spirit and scope of the present application. In addition, under the guidance of the present application, these features and embodiments may be modified to adapt to specific circumstances and materials without departing from the spirit and scope of the present application. Therefore, the present application is not limited by the specific embodiments disclosed herein, and all embodiments falling within the scope of the claims of the present application are within the scope protected by the present application.

Claims

1. A production device for continuously preparing lithium carbonate from lithium hydroxide, Features: The invention comprises a precooler, a reactor, a circulation pump, a carbonized liquid storage tank, a centrifuge, a mother liquid tank, a mother liquid pump and a plate and frame filter press which are connected in sequence through pipelines. The reactor is a continuous reaction device of a four-stage reactor. There are four groups of reactors and circulation pumps. The four groups of reactors are divided into a primary reactor, a secondary reactor, a tertiary reactor and a fourth-stage reactor. The four groups of circulation pumps are divided into a primary circulation pump, a secondary circulation pump, a tertiary circulation pump and a fourth-stage circulation pump.

2. The production device for continuously preparing lithium carbonate from lithium hydroxide according to claim 1, Features: The output end of the precooler is connected to the input end of the primary reactor through a pipeline, and the primary circulation pump is connected to the primary reactor and the secondary reactor through pipelines respectively.

3. The production device for continuously preparing lithium carbonate from lithium hydroxide according to claim 1, Features: The secondary circulation pump is connected to the secondary reactor and the tertiary reactor through pipelines, and the tertiary circulation pump is connected to the tertiary reactor and the quaternary reactor through pipelines.

4. The production device for continuously preparing lithium carbonate from lithium hydroxide according to claim 1, Features: The four-stage circulation pump is connected to the four-stage reactor and the carbonized liquid storage tank through pipelines, the centrifuge is connected to the carbonized liquid storage tank and the mother liquid tank through pipelines, and the mother liquid pump is connected to the mother liquid tank and the plate and frame filter press through pipelines.

5. The production device for continuously preparing lithium carbonate from lithium hydroxide according to claim 1, Features: A lithium hydroxide inlet is arranged at the lower left end of the precooler.

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