Salt separation and recovery device for sodium chloride and lithium chloride

Abstract

The utility model relates to the technical field of lithium carbonate recovery devices, in particular to a salt separation and recovery device for sodium chloride and lithium chloride. The utility model provides a salt separation and recovery device for sodium chloride and lithium chloride, which comprises evaporators, a cooler, a thickener, a centrifugal machine, a mother liquor tank, a condensate water tank, a discharge pump, a vacuum pump and a mother liquor pump which are sequentially connected through pipelines, and the evaporators are three groups of triple-effect circulating evaporators which are arranged in series and can effectively improve the concentration of sodium chloride and lithium chloride; the triple-effect circulating evaporator comprises a first-stage evaporator, a second-stage evaporator and a third-stage evaporator which are sequentially connected through pipelines; according to the recovery device disclosed by the invention, the triple-effect circulating evaporator is designed; according to the lithium carbonate recycling device, evaporation, concentration and crystallization of raw materials can be carried out through the triple-effect circulating evaporator, sodium chloride solid salt and a high-concentration lithium chloride solution can be obtained through centrifugal separation and mother liquor recycling, and the problem that in the prior art, lithium carbonate is slightly dissolved in water, and consequently the lithium carbonate recycling benefit is not ideal is solved.

Description

Technical Field

[0001] The present application relates to the technical field of lithium carbonate recovery devices, and in particular to a sodium chloride and lithium chloride salt separation and recovery device. Background Art

[0002] In the prior art, since the price of lithium carbonate is between RMB 100,000 and 500,000 per ton and it is a high-value product, recycling the lithium element in the positive electrode powder of waste lithium batteries can effectively increase the recycling efficiency of waste batteries.

[0003] After crushing and separation, the battery positive electrode powder is added with hydrochloric acid to react and generate a lithium chloride acid solution with impurities such as carbon powder. After plate and frame filtration and chemical impurity removal, sodium hydroxide is added to adjust the pH value to 7-8. The resulting neutral solution contains two substances, lithium chloride and sodium chloride. Then, it enters the lithium precipitation process and sodium carbonate is added to react to generate lithium carbonate precipitate and sodium chloride solution. After centrifugal separation and washing, a high-purity lithium carbonate product can be obtained.

[0004] However, since lithium carbonate is slightly soluble in water, the solution after centrifugation and washing contains 2-3 g / L of lithium carbonate in addition to a large amount of sodium chloride. Since the concentration of lithium carbonate is too low, this part of the lithium carbonate cannot effectively complete the lithium precipitation reaction and is lost. Utility Model Content

[0005] The problem to be solved by the present application is that the existing lithium carbonate is slightly soluble in water, so that the solution after centrifugation and washing contains a small amount of discarded lithium carbonate that cannot complete the lithium precipitation reaction, thereby resulting in unsatisfactory lithium carbonate recovery efficiency.

[0006] To solve the above technical problems, the present application provides a salt separation and recovery device for sodium chloride and lithium chloride, comprising an evaporator, a cooler, a thickener, a centrifuge, a mother liquor tank, a condensed water tank, a discharge pump, a vacuum pump and a mother liquor pump connected in sequence through pipelines, the evaporator being three groups of triple-effect circulation evaporators arranged in series that can effectively increase the concentration of sodium chloride and lithium chloride, the triple-effect circulation evaporator comprising a primary evaporator, a secondary evaporator and a tertiary evaporator connected in sequence through pipelines.

[0007] Since the recovery device of the present application is designed with a triple-effect circulating evaporator, it is possible to not only evaporate, concentrate and crystallize the raw materials through the triple-effect (circulating evaporator, but also obtain sodium chloride solid salt and high-concentration lithium chloride solution through centrifugal separation and recycling of the mother liquor, thereby solving the problem in the prior art that lithium carbonate is slightly soluble in water, resulting in a small amount of lithium carbonate that cannot be discarded in the solution after centrifugation and washing, thereby resulting in unsatisfactory lithium carbonate recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1Schematic diagram of the production process of the embodiment.

[0009] In the figure: 1. primary heater; 2. secondary heater; 3. tertiary heater; 4. primary separator; 5. secondary separator; 6. tertiary separator; 7. cooler; 8. thickener; 9. centrifuge; 10. mother liquor tank; 11. condensate tank; 12. primary circulation pump; 13. secondary circulation pump; 14. tertiary circulation pump; 15. discharge pump; 16. vacuum pump; 17. mother liquor pump. DETAILED DESCRIPTION

[0010] 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

[0011] The present application relates to a sodium chloride and lithium chloride salt separation and recovery device, such as Figure 1 As shown, the recovery device includes an evaporator, a cooler 7, a thickener 8, a centrifuge 9, a mother liquid tank 10, a condensed water tank 11, a discharge pump 15, a vacuum pump 16 and a mother liquid pump 17 which are sequentially connected by pipelines. In order to effectively improve the concentration of sodium chloride and lithium chloride, the evaporator is three groups of three-effect circulation evaporators arranged in series which can effectively improve the concentration of sodium chloride and lithium chloride. The three-effect circulation evaporator includes a primary evaporator, a secondary evaporator and a tertiary evaporator which are sequentially connected by pipelines.

[0012] The primary evaporator includes a primary heater 1, a primary separator 4, and a primary circulation pump 12 which are connected in sequence through pipelines; the secondary evaporator includes a secondary heater 2, a secondary separator 5, and a secondary circulation pump 13 which are connected in sequence through pipelines; the tertiary evaporator includes a tertiary heater 3, a tertiary separator 6, and a tertiary circulation pump 14 which are connected in sequence through pipelines.

[0013] The bottom side wall of the first-stage heater 1 has a raw material inlet, the top side wall of the first-stage heater 1 has a steam inlet, the top output end of the first-stage collector is connected to the side wall input end of the first-stage separator 4 through a pipeline, the output end of the first-stage circulation pump 12 is connected to the input end of the first-stage heater 1 through a pipeline, and the input end of the first-stage circulation pump 12 is connected to the bottom output end of the first-stage separator 4 through a pipeline, so that with the help of the rotation of the first-stage circulation pump 12, the raw material is evenly pushed in from the bottom of the first-stage heater 1, and then the heated raw material is pushed out from the top of the first-stage heater 1, and then enters the first-stage separator 4 to complete the gas-liquid separation operation.

[0014] The secondary evaporator and the tertiary evaporator have the same arrangement as the primary evaporator. The gas and liquid separated by the primary evaporator are the raw materials and steam of the secondary evaporator, and the gas and liquid separated by the secondary evaporator are the raw materials and steam of the tertiary evaporator. Therefore, after the raw materials are concentrated three times, a crystal slurry liquid for precipitating sodium chloride crystals is obtained.

[0015] The input end of the discharge pump 15 is connected to the output end of the tertiary circulation pump 14 through a pipeline, the output end of the discharge pump 15 is connected to the input end of the thickener 8 through a pipeline, the output end of the thickener 8 is connected to the input end of the centrifuge 9 through a pipeline, the output end of the centrifuge 9 is connected to the input end of the mother liquid tank 10 through a pipeline, the input end of the mother liquid pump 17 is connected to the output end of the mother liquid tank 10 through a pipeline, the output end of the mother liquid pump 17 is connected to the tertiary separator 6 through a pipeline, the input end of the cooler 7 is connected to the top output end of the tertiary separator 6 through a pipeline, and the output end of the cooler 7 is respectively connected to the vacuum pump 16 and the condensed water tank 11 through pipelines, which are used to condense and recover the recycled steam, adjust the solid-liquid ratio of the crystal paddle liquid through the thickener 8, and then enter the solid-liquid separation operation of the centrifuge 9 to obtain sodium chloride solid salt. Since the surface of the solid salt after centrifugation still contains There is 3%-5% water content in lithium chloride mother liquor, so it is necessary to perform water spray washing operation in the centrifuge 9 to replace the mother liquor containing lithium chloride on the surface of the solid salt. The mother liquor enters the mother liquor tank 10 and is pumped into the three-stage separator 6 by the mother liquor pump 17 for mother liquor circulation. When the lithium content in the mother liquor reaches about 10g / L, the valve returning to the evaporation system continues to be opened, and the regulating valve for mother liquor discharge is opened at the same time to discharge into the next process. During the discharge process, the lithium concentration in the mother liquor is detected in real time, and the opening of the discharge regulating valve is guided by the measured lithium concentration data. The lithium concentration in the mother liquor is controlled by the size of the discharge volume to achieve continuous and stable production, which not only improves production efficiency, but also provides qualified concentration materials for the subsequent lithium precipitation process. The device can improve the lithium carbonate recovery rate by 15-20% as a whole. If the average price of lithium carbonate is 200,000 yuan / ton, the income can be increased by 30,000 to 40,000 yuan per ton.

[0016] 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 sodium chloride and lithium chloride salt recovery device, characterized in that: It includes an evaporator, a cooler, a thickener, a centrifuge, a mother liquor tank, a condensed water tank, a discharge pump, a vacuum pump and a mother liquor pump which are sequentially connected through pipelines. The evaporator is a three-stage circulating evaporator which is arranged in series and can effectively increase the concentration of sodium chloride and lithium chloride. The three-effect circulating evaporator includes a primary evaporator, a secondary evaporator and a tertiary evaporator which are sequentially connected through pipelines.

2. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 1, characterized in that: The primary evaporator comprises a primary heater, a primary separator and a primary circulation pump which are sequentially connected through pipelines. The bottom side wall of the primary heater is provided with a raw material inlet, and the top side wall of the primary heater is provided with a steam inlet.

3. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 2, characterized in that: The secondary evaporator includes a secondary heater, a secondary separator and a secondary circulation pump which are sequentially connected through pipelines.

4. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 3, characterized in that: The three-stage evaporator includes a three-stage heater, a three-stage separator and a three-stage circulation pump which are sequentially connected through pipelines.

5. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 2, characterized in that: The top output end of the primary collector is connected to the side wall input end of the primary separator through a pipeline, the output end of the primary circulation pump is connected to the input end of the primary heater through a pipeline, and the input end of the primary circulation pump is connected to the bottom output end of the primary separator through a pipeline.

6. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 1, characterized in that: The layout of the secondary evaporator, the tertiary evaporator and the primary evaporator is the same.

7. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 2, characterized in that: The gas and liquid separated by the first-stage evaporator are the raw materials and steam of the second-stage evaporator, and the gas and liquid separated by the second-stage evaporator are the raw materials and steam of the third-stage evaporator.

8. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 4, characterized in that: The input end of the discharge pump is connected to the output end of the tertiary circulation pump through a pipeline, the output end of the discharge pump is connected to the input end of the thickener through a pipeline, the output end of the thickener is connected to the input end of the centrifuge through a pipeline, the output end of the centrifuge is connected to the input end of the mother liquid tank through a pipeline, the input end of the mother liquid pump is connected to the output end of the mother liquid tank through a pipeline, and the output end of the mother liquid pump is connected to the tertiary separator through a pipeline.

9. The salt separation and recovery device for sodium chloride and lithium chloride according to claim 1, characterized in that: The input end of the cooler is connected to the top output end of the three-stage separator through a pipeline, and the output end of the cooler is connected to the vacuum pump and the condensed water tank through pipelines respectively.

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