System for recycling trace lithium and purifying sodium sulfate

Abstract

The utility model relates to the technical field of trace ion separation, in particular to a system for recovering trace lithium and purifying sodium sulfate. The system comprises a dissolving system (1), a heat exchange system (2), an extraction separation system (3), a lithium salt concentration system (4) and a sodium salt concentration, crystallization and drying system (5), the inlet end of the dissolving system is connected with a sodium sulfate decahydrate product input port, and the outlet end of the dissolving system is connected with the heat exchange system (2); the heat exchange system (2) is communicated with the extraction separation system (3); the extraction separation system (3) is provided with a lithium-containing salt outlet and a sodium-containing salt outlet, and is connected with the lithium salt concentration system (4) through the lithium-containing salt outlet and connected with the sodium salt concentration, crystallization and drying system (5) through the sodium-containing salt outlet. The system can recover lithium resources from sodium sulfate decahydrate and improve the purity of sodium sulfate, the whole system is stable in operation, and the metal yield and the product quality can be remarkably improved.

Description

Technical Field

[0001] This utility model relates to the field of trace ion separation technology, specifically a system for recovering trace amounts of lithium and purifying sodium sulfate. Background Technology

[0002] Lithium-ion batteries are a type of battery that uses lithium metal or lithium alloy as the positive / negative electrode material and a non-aqueous electrolyte solution. As a secondary energy source, they currently occupy a significant market share. The main components of their positive electrode material are metals such as nickel, cobalt, manganese, and lithium. Therefore, the recycling process is currently a focus of attention.

[0003] During the production and recycling of lithium salts, various byproducts will carry away some lithium resources. For example, in the process of producing lithium salts from spodumene using the sulfuric acid process, the produced sodium sulfate decahydrate byproduct will contain lithium resources, which will cause lithium loss and reduce the quality of the finished sodium sulfate product.

[0004] Because this portion of entrained lithium resources has a low content, it is difficult to recycle and utilize using conventional processing methods, and the quality of sodium sulfate is generally not controlled. Therefore, few companies currently use comprehensive processing of sodium sulfate decahydrate to improve economic efficiency.

[0005] Therefore, if we can improve the system to improve the quality of sodium sulfate while recovering trace amounts of lithium, it will be of great significance for solving environmental and resource waste problems. Utility Model Content

[0006] To address the problems mentioned in the background art, this utility model proposes a system for recovering trace amounts of lithium and purifying sodium sulfate. This system can recover lithium resources from sodium sulfate decahydrate and improve the purity of sodium sulfate. The overall system operates stably, significantly improving metal yield and product quality, and effectively solving the problems of difficult trace lithium recovery and low-quality finished sodium sulfate.

[0007] To achieve the above-mentioned objectives, the specific technical solution of this utility model is as follows:

[0008] A system for recovering trace amounts of lithium and purifying sodium sulfate, the system comprising a dissolution system, a heat exchange system, an extraction and separation system, a lithium salt concentration system, and a sodium salt concentration, crystallization, and drying system;

[0009] The inlet of the dissolution system is connected to the sodium sulfate decahydrate product inlet, and the outlet is connected to the heat exchange system.

[0010] The heat exchange system is connected to the extraction and separation system;

[0011] The extraction and separation system is equipped with a lithium salt outlet and a sodium salt outlet, and is connected to a lithium salt concentration system through the lithium salt outlet and to a sodium salt concentration, crystallization and drying system through the sodium salt outlet.

[0012] Furthermore, in the system for recovering trace amounts of lithium and purifying sodium sulfate, the dissolution system includes a sodium sulfate decahydrate feed and metering device, a dissolving water feed and metering device, and a stirring tank; the sodium sulfate decahydrate feed and metering device is connected to the stirring tank, and the dissolving water feed and metering device is also connected to the stirring tank.

[0013] Furthermore, a matching control valve or regulating valve is installed on the sodium sulfate decahydrate feed and metering device in the system for recovering trace amounts of lithium and purifying sodium sulfate; a matching control valve or regulating valve is also installed on the dissolved water feed and metering device.

[0014] The dissolving system is configured with sodium sulfate solution. The dissolving system can be configured to produce a saturated sodium sulfate solution by adjusting the feed rate of sodium sulfate decahydrate and the feed rate of dissolving water.

[0015] Furthermore, in the system for recovering trace amounts of lithium and purifying sodium sulfate, the heat exchange system includes a heat exchange device and a heat exchange medium reflux device; the heat exchange device is provided with a sodium sulfate solution inlet and outlet, and a heat exchange medium inlet and outlet, the sodium sulfate solution inlet and outlet being connected to a dissolution system and an extraction separation system, respectively, and the heat exchange medium inlet and outlet being connected to the heat exchange medium reflux device.

[0016] The heat exchange system is also equipped with a temperature sensor, which is located at the inlet of the sodium sulfate solution on the heat exchange device. The heat exchange system can control the heat exchange efficiency based on the incoming temperature of the sodium sulfate solution, maintaining the outlet temperature at a level that the extraction system can withstand.

[0017] Furthermore, in the system for recovering trace amounts of lithium and purifying sodium sulfate, the extraction and separation system includes an extraction device, a washing device, and a back-extraction device; the inlet of the extraction device is connected to the outlet of the sodium sulfate solution, the outlet of the extraction device is connected to the inlet of the washing device, and the washing device is connected to the back-extraction device.

[0018] Furthermore, the washing device in the system for recovering trace amounts of lithium and purifying sodium sulfate is provided with two outlets, namely washing device outlet one and washing device outlet two; wherein washing device outlet one is connected to the sodium salt concentration, crystallization and drying system, and washing device outlet two is connected to the inlet of the back-extraction device; the back-extraction device is also provided with two outlets, namely back-extraction device outlet one and back-extraction device outlet two; back-extraction device outlet one is connected to the lithium salt concentration system, and back-extraction device outlet two is connected to the inlet of the extraction device.

[0019] The extraction and separation system uses the above components to perform extraction, washing, and back-extraction processes, and outputs lithium salt solution and sodium salt solution.

[0020] The extraction and separation system can also adjust parameters in real time according to the lithium concentration in the incoming material to keep the lithium concentration in the sodium salt solution reduced to the expected value.

[0021] Furthermore, in the system for recovering trace amounts of lithium and purifying sodium sulfate, the lithium salt concentration system includes an evaporation concentration device and a condensation device; the evaporation concentration device is respectively provided with a feed inlet, a condensate outlet and a discharge outlet;

[0022] The inlet of the evaporation and concentration device is connected to the outlet of the back-extraction device, and the outlet of the evaporation and concentration device is connected out of the system; the inlet of the condensation device is connected to the steam outlet of the evaporation and concentration device, and the outlet of the condensation device is connected to the dissolved water inlet and metering device.

[0023] Lithium salt concentration systems can increase lithium concentration for the production of lithium hydroxide or lithium carbonate, while simultaneously recovering condensate and returning it to the dissolution system.

[0024] Furthermore, in the system for recovering trace amounts of lithium and purifying sodium sulfate, the sodium salt concentration, crystallization, and drying system includes an evaporation and concentration device, a condensation device, and a solid-liquid separation device; the inlet of the evaporation and concentration device is connected to the outlet of the washing device, and the outlet of the evaporation and concentration device is connected to the solid-liquid separation device; the inlet of the condensation device is connected to the steam outlet of the evaporation and concentration device, and the outlet of the condensation device is connected to the dissolved water inlet and metering device.

[0025] Furthermore, in the system for recovering trace amounts of lithium and purifying sodium sulfate, the solid-liquid separation device is provided with a sodium sulfate crystal outlet and a mother liquor outlet, the mother liquor outlet being connected to the outlet of the condensation device.

[0026] The sodium sulfate concentrate, crystallization, and drying system produces sodium sulfate, crystallization mother liquor, and concentrated condensate. Both the crystallization mother liquor and the concentrated condensate are returned to the dissolution system to dissolve sodium sulfate decahydrate.

[0027] Compared with the prior art, the beneficial effects of this utility model are reflected in:

[0028] (1) Most of the lithium entrained in sodium sulfate decahydrate can be recovered through an extraction and separation system;

[0029] (2) Sodium sulfate decahydrate can be crystallized after extraction, which can improve its purity. That is, the system can recover lithium while improving the purity of sodium sulfate.

[0030] (3) The system can recover lithium resources from sodium sulfate decahydrate and improve the purity of sodium sulfate. The overall system operates stably and can significantly improve the metal yield and product quality. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0032] Figure 1 This is a schematic diagram showing the connection relationship of the system for recovering trace amounts of lithium and purifying sodium sulfate as described in this utility model;

[0033] The system includes: 1. Dissolution system; 2. Heat exchange system; 3. Extraction and separation system; 4. Lithium salt concentration system; 5. Sodium salt concentration, crystallization and drying system. Detailed Implementation

[0034] The exemplary embodiments will now be described in more full detail. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more complete and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0035] Furthermore, the described features or characteristics may be combined in any suitable manner in one or more embodiments. In the following description, numerous specific details are provided to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application may be practiced without one or more of the specific details, or other methods, steps, etc. may be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0036] The embodiments are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the actual situation.

[0037] It should be noted that "multiple" in this article refers to two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A alone, A and B simultaneously, or B alone. The character " / " generally indicates that the preceding and following related objects have an "or" relationship.

[0038] It should be noted that the order in which the methods are mentioned in the specification and claims of this application should be understood to be interchangeable where appropriate, so that the embodiments of this application described herein can be implemented in a different order than those described.

[0039] To make the objectives, technical solutions, and advantages of this utility model clearer, the technical solutions in the embodiments of this utility model will be clearly and completely described below in conjunction with the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of the embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0040] Example 1

[0041] This utility model embodiment relates to a system for recovering trace amounts of lithium and purifying sodium sulfate, the connection diagram of which is shown below. Figure 1 As shown, the system includes: a dissolution system 1, a heat exchange system 2, an extraction and separation system 3, a lithium salt concentration system 4, and a sodium salt concentration, crystallization, and drying system 5;

[0042] The inlet of the dissolution system is connected to the sodium sulfate decahydrate product inlet, and the outlet is connected to the heat exchange system.

[0043] The heat exchange system is connected to the extraction and separation system;

[0044] The extraction and separation system is equipped with a lithium salt outlet and a sodium salt outlet, and is connected to a lithium salt concentration system through the lithium salt outlet and to a sodium salt concentration, crystallization and drying system through the sodium salt outlet.

[0045] The dissolution system 1 includes a sodium sulfate decahydrate feeding and metering device, a dissolving water feeding and metering device, and a mixing tank; the sodium sulfate decahydrate feeding and metering device is connected to the mixing tank, and the dissolving water feeding and metering device is connected to the mixing tank.

[0046] The sodium sulfate decahydrate feed and metering device is equipped with a matching control valve or regulating valve; the dissolved water feed and metering device is also equipped with a matching control valve or regulating valve.

[0047] A sodium sulfate solution is prepared in dissolving system 1. The dissolving system 1 prepares a saturated sodium sulfate solution by adjusting the feed rate of sodium sulfate decahydrate and the feed rate of dissolving water.

[0048] The heat exchange system 2 includes a heat exchange device and a heat exchange medium reflux device; in this embodiment, the heat exchange medium is water.

[0049] The heat exchange device is equipped with a sodium sulfate solution inlet and outlet, and a heat exchange medium inlet and outlet. The sodium sulfate solution inlet and outlet are connected to the dissolution system and the extraction and separation system, respectively, and the heat exchange medium inlet and outlet are connected to the heat exchange medium reflux device.

[0050] The heat exchange system is equipped with a temperature sensor, which can control the heat exchange efficiency based on the temperature of the sodium sulfate solution feed, and maintain the outlet temperature at a level that the extraction system can withstand.

[0051] The extraction and separation system 3 includes an extraction device, a washing device, and a back-extraction device; the inlet of the extraction device is connected to the outlet of the sodium sulfate solution, the outlet of the extraction device is connected to the inlet of the washing device, and the washing device is connected to the back-extraction device.

[0052] Furthermore, the washing device in the system for recovering trace amounts of lithium and purifying sodium sulfate is provided with two outlets, namely washing device outlet one and washing device outlet two; wherein washing device outlet one is connected to the sodium salt concentration, crystallization and drying system, and washing device outlet two is connected to the inlet of the back-extraction device; the back-extraction device is also provided with two outlets, namely back-extraction device outlet one and back-extraction device outlet two; back-extraction device outlet one is connected to the lithium salt concentration system, and back-extraction device outlet two is connected to the inlet of the extraction device.

[0053] The extraction and separation system uses the above components to perform extraction, washing, and back-extraction processes, and outputs lithium salt solution and sodium salt solution.

[0054] The extraction and separation system can also adjust parameters in real time according to the lithium concentration in the incoming material to keep the lithium concentration in the sodium salt solution reduced to the expected value.

[0055] The lithium salt concentration system 4 includes an evaporation and concentration device and a condensation device. The evaporation and concentration device is provided with a feed inlet, a steam outlet and a discharge outlet. The feed inlet of the evaporation and concentration device is connected to the outlet of the back-extraction device of the extraction and separation system 3. The discharge outlet of the evaporation and concentration device is discharged from the system. The inlet of the condensation device is connected to the steam outlet of the evaporation and concentration device. The outlet of the condensation device is connected to the dissolved water feed and metering device of the dissolving system 1.

[0056] Lithium salt concentration systems can increase lithium concentration for the production of lithium hydroxide or lithium carbonate, while simultaneously recovering condensate and returning it to the dissolution system.

[0057] The sodium salt concentration, crystallization and drying system 5 includes an evaporation and concentration device, a condensation device, and a solid-liquid separation device; the inlet of the evaporation and concentration device is connected to the outlet of the washing device of the extraction and separation system 3, and the outlet of the evaporation and concentration device is connected to the solid-liquid separation device; the inlet of the condensation device is connected to the steam outlet of the evaporation and concentration device, and the outlet of the condensation device is connected to the dissolved water feed and metering device on the dissolving system 1.

[0058] The solid-liquid separation device is equipped with a sodium sulfate crystal outlet and a mother liquor outlet, respectively, and the mother liquor outlet is connected to the outlet of the condensation device.

[0059] The sodium sulfate concentrate, crystallization, and drying system produces sodium sulfate, crystallization mother liquor, and concentrated condensate. Both the crystallization mother liquor and the concentrated condensate are returned to the dissolution system to dissolve sodium sulfate decahydrate.

[0060] This system can recover trace amounts of lithium from sodium sulfate decahydrate and further extract sodium sulfate, ultimately producing a high-concentration lithium-containing solution and sodium sulfate product.

[0061] The embodiments described above merely illustrate specific implementation methods of this application, and while the descriptions are detailed and specific, they should not be construed as limiting the scope of protection of this application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the technical solution of this application, and these modifications and improvements all fall within the scope of protection of this application.

[0062] The background section is provided to generally present the context of this utility model. The work of the currently named inventors, the work to the extent described in this background section, and aspects described in this section that did not constitute prior art at the time of filing are neither expressly nor impliedly acknowledged as prior art to this utility model.

Claims

1. A system for recovering trace amounts of lithium and purifying sodium sulfate, characterized in that: The system includes a dissolution system (1), a heat exchange system (2), an extraction and separation system (3), a lithium salt concentration system (4), and a sodium salt concentration, crystallization, and drying system (5). The inlet of the dissolution system (1) is connected to the sodium sulfate decahydrate product inlet, and the outlet is connected to the heat exchange system (2). The heat exchange system (2) is connected to the extraction and separation system (3); The extraction and separation system (3) is equipped with a lithium salt outlet and a sodium salt outlet, and is connected to the lithium salt concentration system (4) through the lithium salt outlet and to the sodium salt concentration crystallization and drying system (5) through the sodium salt outlet.

2. The system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 1, characterized in that: The dissolution system (1) includes a sodium sulfate decahydrate feeding and metering device, a dissolving water feeding and metering device, and a stirring tank; the sodium sulfate decahydrate feeding and metering device is connected to the stirring tank, and the dissolving water feeding and metering device is also connected to the stirring tank.

3. The system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 2, characterized in that: A matching control valve is installed on the sodium sulfate decahydrate feed and metering device; a matching control valve is also installed on the dissolved water feed and metering device.

4. The system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 2, characterized in that: The heat exchange system (2) includes a heat exchange device and a heat exchange medium reflux device. The heat exchange device is provided with a sodium sulfate solution inlet and outlet, and a heat exchange medium inlet and outlet. The sodium sulfate solution inlet and outlet are respectively connected to the dissolution system (1) and the extraction separation system (3). The heat exchange medium inlet and outlet are connected to the heat exchange medium reflux device.

5. The system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 4, characterized in that: The extraction and separation system (3) includes an extraction device, a washing device, and a back-extraction device; the inlet of the extraction device is connected to the outlet of the sodium sulfate solution in claim 4, the outlet of the extraction device is connected to the inlet of the washing device, and the washing device is connected to the back-extraction device.

6. The system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 5, characterized in that, The washing device has two outlets, namely washing device outlet one and washing device outlet two; washing device outlet one is connected to the sodium salt concentration crystallization drying system (5), and washing device outlet two is connected to the inlet of the back-extraction device; the back-extraction device also has two outlets, namely back-extraction device outlet one and back-extraction device outlet two; back-extraction device outlet one is connected to the lithium salt concentration system (4), and back-extraction device outlet two is connected to the inlet of the extraction device.

7. The system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 6, characterized in that, The lithium salt concentration system (4) includes an evaporation concentration device and a condensation device; the evaporation concentration device is respectively provided with a feed inlet, a steam outlet and a discharge outlet; The feed inlet of the evaporation and concentration device is connected to the outlet of the back-extraction device as described in claim 5, and the discharge port of the evaporation and concentration device is connected out of the system; the inlet of the condensation device is connected to the steam outlet of the evaporation and concentration device, and the outlet of the condensation device is connected to the dissolved water feed and metering device as described in claim 2.

8. The system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 7, characterized in that, The sodium salt concentration, crystallization and drying system (5) includes an evaporation and concentration device, a condensation device and a solid-liquid separation device; the inlet of the evaporation and concentration device is connected to the outlet of the washing device as described in claim 5, and the outlet of the evaporation and concentration device is connected to the solid-liquid separation device; the inlet of the condensation device is connected to the steam outlet of the evaporation and concentration device, and the outlet of the condensation device is connected to the dissolved water feed and metering device as described in claim 2.

9. A system for recovering trace amounts of lithium and purifying sodium sulfate according to claim 8, characterized in that, The solid-liquid separation device is equipped with a sodium sulfate crystal outlet and a mother liquor outlet, and the mother liquor outlet is connected to the outlet of the condensation device.

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