Continuous carbonization and purification device for lithium carbonate

Abstract

The utility model relates to the technical field of lithium carbonate preparation devices, in particular to a continuous carbonization and purification device for lithium carbonate. The utility model provides a lithium carbonate continuous carbonization and purification device which comprises three carbonization towers, a purification liquid storage tank, a pyrolysis tower, a pyrolysis heater, a thickener, a liquid storage tank and a centrifugal machine which are sequentially connected through pipelines, and the three carbonization towers are divided into a first-stage carbonization tower, a second-stage carbonization tower and a third-stage carbonization tower; the carbonization towers are sequentially arranged in series, and the step-by-step conveying of slurry is realized through a discharge pump arranged at the upper part of a pipeline; one side of the pyrolysis tower is connected with a recovery system for condensing and recovering carbon dioxide; the recovery system comprises an indirect condenser, a normal pressure buffer tank, a compressor unit, a pressurization buffer tank, a two-stage condenser, a water tank, a liquid storage tank and a vaporizer which are sequentially connected through pipelines. According to the carbonization and purification device, the carbonization tower, the pyrolysis tower and the recovery system are designed, so that the water dissolving and purification conversion operation between lithium carbonate and lithium bicarbonate is realized.

Description

Technical Field

[0001] This application relates to the technical field of lithium carbonate preparation devices, and particularly to a continuous carbonization and purification device for lithium carbonate. Background Art

[0002] In the prior art, lithium carbonate, as the basic salt of lithium salts, is the raw material for preparing lithium compounds and metallic lithium, and is also the key raw material for lithium-ion batteries. It is increasingly widely used in fields such as electric vehicles and renewable energy storage. Due to the limitations of production technology and the characteristics of salt lake brine itself, currently, crude lithium carbonate (85 - 98%) and industrial-grade lithium carbonate (98.5 - 99.0%) are mostly used as raw materials, and further purification is carried out to produce high-purity battery-grade lithium carbonate (99.5 - 99.9%). For this purpose, the heating decomposition method is usually used to heat lithium carbonate to a certain temperature. By controlling the heating temperature and time, lithium carbonate with a relatively high purity can be obtained. However, in the actual operation, due to the existence of residual heat, lithium carbonate is easily decomposed into sodium carbonate and lithium salts, resulting in an increase in the loss of lithium carbonate. Therefore, how to improve the purity of lithium carbonate while reducing its loss is particularly important. Summary of the Utility Model

[0003] The problem to be solved by this application is that when the existing lithium carbonate is purified by the heating decomposition method, due to the existence of residual heat, lithium carbonate is easily decomposed into sodium carbonate and lithium salts, resulting in an increase in the loss of lithium carbonate.

[0004] To solve the above technical problems, this application provides a continuous carbonization and purification device for lithium carbonate, which includes a carbonization tower, a purified liquid storage tank, a pyrolysis tower, a pyrolysis heater, a thickener, a liquid storage tank, and a centrifuge connected in sequence through pipelines. The number of carbonization towers is three, which are divided into a primary carbonization tower, a secondary carbonization tower, and a tertiary carbonization tower. The carbonization towers are arranged in series in sequence, and the slurry is gradually transported through the discharge pumps arranged in the upper part of the pipelines. One side of the pyrolysis tower is connected with a recovery system for condensing and recovering carbon dioxide. The recovery system includes an indirect condenser, an atmospheric buffer tank, a compressor unit, a pressurized buffer tank, a two-stage condenser, a water tank, a liquid storage tank, and a vaporizer connected in sequence through pipelines.

[0005] Since the carbonization and purification device of this application is designed with a carbonization tower, a pyrolysis tower, and a recovery system, it can not only realize the water-soluble purification conversion operation between lithium carbonate and lithium bicarbonate through the carbonization tower and the pyrolysis tower, but also realize the recovery and utilization operation of carbon dioxide and moisture during the purification process of lithium carbonate through the recovery system, solving the problem that when the existing lithium carbonate is purified by the heating decomposition method, due to the existence of residual heat, lithium carbonate is easily decomposed into sodium carbonate and lithium salts, resulting in an increase in the loss of lithium carbonate. Brief Description of the Drawings

[0006] Figure 1 It is a process flow diagram of the three-stage carbonization of lithium carbonate.

[0007] Figure 2 It is a process flow diagram of the pyrolysis of lithium bicarbonate.

[0008] Figure 3 It is a process flow diagram of the recovery of carbon dioxide.

[0009] In the figure: 1. Feed pump; 2. First-stage carbonization tower; 3. Second-stage carbonization tower; 4. Third-stage carbonization tower; 5. Discharge pump; 6. Purified liquid storage tank; 7. Feed pump; 8. Pyrolysis heater; 9. Pyrolysis circulation pump; 10. Pyrolysis tower; 11. Thickener; 12. Slurry pump; 13. Liquid storage tank; 14. Centrifuge; 15. Mother liquor heat exchanger; 16. Clear liquid tank; 17. Mother liquor tank; 18. Raw steam condensate tank; 19. Indirect condenser; 20. Induced draft fan; 21. Water tank; 22. Water pump; 23. Atmospheric pressure buffer tank; 24. Compressor unit; 25. Two-stage condenser; 26. Pressurized buffer tank; 27. Vaporizer; 28. Liquid storage tank. Specific embodiments

[0010] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present application. Embodiment

[0011] The present application relates to a lithium carbonate continuous carbonization and purification device. As Figure 1 shown, the carbonization and purification device includes a carbonization tower, a pyrolysis tower 10, and a thickener 11 connected in sequence through pipelines. Among them, the number of carbonization towers is three, which are divided into a first-stage carbonization tower 2, a second-stage carbonization tower 3, and a third-stage carbonization tower 4. The carbonization towers are arranged in series in sequence and the slurry is transported step by step through a discharge pump 5. A feed pump 1 for transporting slurry into the first-stage carbonization tower 2 is arranged on the left side of the first-stage carbonization tower 2. Among them, the slurry is prepared by mixing raw materials (industrial-grade lithium carbonate or crude lithium) with deionized water (separated mother liquor, secondary steam condensate), and the mixing ratio is 1:20 - 30. Then, it reacts with carbon dioxide at a certain pressure and temperature through three carbonization towers to obtain a lithium bicarbonate solution. In order to achieve full mixing between the slurry and carbon dioxide, therefore, the slurry and carbon dioxide gas operate in countercurrent in the carbonization tower. The prepared lithium bicarbonate solution is filtered through an impurity removal system and then stored in a purified liquid storage tank 6. The carbonization tower adopts a structure with a high length-diameter ratio and without stirring.

[0012] The purified liquid storage tank 6 is connected to the pyrolysis tower 10 through a pipeline, and the directional transportation of the lithium bicarbonate solution is realized by means of a feed pump 7 arranged on the upper part of the pipeline. One side of the pyrolysis tower 10 is connected to a pyrolysis heater 8 through a pipeline. The pyrolysis heater 8 conveys saturated steam to the pyrolysis tower 10 by means of a pyrolysis circulation pump 9 arranged on the upper part of the pipeline, so as to promote the heat exchange and temperature rise of the slurry inside the pyrolysis tower 10. The other side of the pyrolysis tower 10 is connected to a thickener 11 for thickening the pyrolyzed slurry through a pipeline. One side of the thickener 11 is connected to a liquid storage tank 13 through a pipeline with a slurry pump 12. One side of the liquid storage tank 13 is respectively connected to two groups of centrifuges 14 through pipelines, so that the thickened slurry is conveyed to the liquid storage tank 13 by the slurry pump 12, and then battery-grade lithium carbonate is obtained through centrifugal separation, drying, screening, iron removal, crushing, mixing and packaging by the centrifuges 14.

[0013] One side of the pyrolysis tower 10 is also connected to a recovery system for condensing and recovering carbon dioxide. The recovery system includes an indirect condenser 18, an atmospheric pressure buffer tank 22, a compressor unit 23, a pressurized buffer tank 25, a two-stage condenser 24, a water tank 20, a liquid storage tank 27, and a vaporizer 26 that are connected in sequence through pipelines. One end of the indirect condenser 18 is connected to the atmospheric pressure buffer tank 22 through a pipeline with an induced draft fan 19, so as to convey the condensed carbon dioxide to it by means of the induced draft fan 19. The other end of the indirect condenser 18 is connected to a water tank 20 for receiving condensed water through a pipeline. The water tank 20 discharges the condensed water through a pipeline with a water pump 21 for flushing the pipeline or preparing the liquid. The atmospheric pressure buffer tank 22 is connected to the compressor unit 23 through a pipeline, so as to compress the volume of carbon dioxide. One end of the compressor unit 23 is connected to the compression buffer tank through a pipeline with a two-stage condenser 24, so as to perform two condensations on the compressed carbon dioxide and then convey it to the compression buffer tank for storage. The compression buffer tank is connected to the liquid storage tank 27 through a pipeline with a vaporizer 26, so as to convert the compressed carbon dioxide through the vaporizer 26 and store it in a liquid state. The recovered carbon dioxide can be returned to the carbonation section for reuse, and the carbon dioxide lost in the system is supplemented by gasifying liquid carbon dioxide.

[0014] Generally speaking, terms should be understood at least in part by their use in context. For example, at least in part depending on the context, the term "one or more" used in the text can be used to describe any feature, structure or property with a singular meaning, or can be used to describe a combination of features, structures or properties with a plural meaning. Similarly, at least in part depending on the context, terms such as "a" or "the" can also be understood as conveying a singular usage or conveying a plural usage.

[0015] It should be easily understood that the terms "on", "above", and "over" in this disclosure should be interpreted in the broadest manner, such that "on" not only means "directly on something", but also includes the meaning of "on something" with intermediate features or layers therebetween, and "above" or "over" not only includes the meaning of "above" or "over something", but may also include the meaning of "above" or "over something" with no intermediate features or layers therebetween (i.e., directly on something).

[0016] In addition, for the sake of convenience of description, spatial relative terms may be used in the text, such as "below", "beneath", "under", "above", "over", etc., to describe the relationship of one element or feature relative to other elements or features as shown in the figures. Spatial relative terms are intended to encompass different orientations of the device in use or operation other than the orientation shown in the drawings. The device may have other orientations (rotated 90 degrees or in other orientations), and the spatial relative descriptive terms used in the text may be interpreted accordingly as well.

[0017] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit them; although the present application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A lithium carbonate continuous carbonization and purification device, characterized in that: It includes a carbonization tower, a purified liquid storage tank, a pyrolysis tower, a pyrolysis heater, a thickener, a liquid storage tank, and a centrifuge which are sequentially connected through pipelines. There are three carbonization towers, which are divided into a primary carbonization tower, a secondary carbonization tower, and a tertiary carbonization tower. The carbonization towers are sequentially arranged in series and the discharge pumps arranged on the upper part of the pipelines realize the step-by-step transportation of the slurry. One side of the pyrolysis tower is connected to a recovery system for condensing and recovering carbon dioxide. The recovery system includes an indirect condenser, a normal pressure buffer tank, a compressor unit, a pressurized buffer tank, a two-stage condenser, a water tank, a liquid storage tank, and a vaporizer which are sequentially connected through pipelines.

2. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: The purified liquid storage tank is connected to the pyrolysis tower through a pipeline, and the lithium bicarbonate solution is directional transported by means of a feed pump arranged on the upper part of the pipeline.

3. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: One side of the pyrolysis tower is connected to a pyrolysis heater through a pipeline, and the pyrolysis heater transports saturated steam to the pyrolysis tower by means of a pyrolysis circulation pump arranged on the upper part of the pipeline.

4. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: The other side of the pyrolysis tower is connected to a thickener for thickening the pyrolysis slurry through a pipeline, one side of the thickener is connected to a liquid storage tank through a pipeline with a slurry pump, and one side of the liquid storage tank is connected to two sets of centrifuges through pipelines.

5. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: One end of the indirect condenser is connected to the atmospheric pressure buffer tank through a pipeline with an induced draft fan, and the other end of the indirect condenser is connected to the pyrolysis tower through a pipeline.

6. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: The other end of the indirect condenser is connected to a water tank for receiving condensed water through a pipeline. The water tank discharges the condensed water through a pipeline with a water pump for flushing the pipeline or preparing liquid.

7. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: The atmospheric pressure buffer tank is connected to the compressor unit through a pipeline, and one end of the compressor unit is connected to the compression buffer tank through a pipeline with a two-stage condenser.

8. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: The compression buffer tank is connected to the liquid storage tank through a pipeline with a vaporizer.

9. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: The slurry and carbon dioxide gas are operated in countercurrent in the carbonization tower.

10. The lithium carbonate continuous carbonization and purification device according to claim 1, characterized in that: A raw material pump for conveying slurry into the first-stage carbonization tower is arranged on the left side thereof.

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