Treatment device for lithium precipitation wastewater of lithium hydroxide or lithium carbonate

Abstract

The utility model provides a treatment device for lithium precipitation wastewater of lithium hydroxide or lithium carbonate, and relates to the technical field of water treatment. The treatment device provided by the utility model comprises a collecting tank, a pH adjusting system, a first filtering device, a reverse osmosis device, a forward osmosis device, an evaporation concentration device, a neutralization reaction tank, a precipitation separation device and a freezing crystallization device. The treatment device is simple in structure and reasonable in design, water can be recycled through cooperation of all the structures, and meanwhile lithium in waste water can be recycled; through the cooperation between the nanofiltration system and the reverse osmosis device, the energy consumption and investment of the evaporator are reduced; through the design of the forward osmosis device, the energy consumption of the evaporation and concentration device is effectively reduced, and the treatment energy consumption is reduced on the whole; the method has economic and social benefits and has research and popularization values.

Description

Technical Field

[0001] The utility model relates to the technical field of water treatment, in particular to a treatment device for lithium hydroxide or lithium carbonate lithium precipitation wastewater. Background Art

[0002] As a clean, efficient and environmentally friendly energy storage device, new energy lithium batteries will be favored and sought after by more people. Lithium is an indispensable carrier and transmitter of energy in batteries. Lithium carbonate or lithium hydroxide is the main component of the positive electrode material and electrolyte in lithium batteries, accounting for the majority of the cost.

[0003] The lithium hydroxide / lithium carbonate production process mainly uses lithium ore concentrate and salt lake brine as raw materials. The conventional production process is to acid dissolve lithium ore concentrate to remove impurities and then evaporate and precipitate, or to extract lithium from salt lake brine and concentrate it, and then precipitate it. Both production processes will produce lithium precipitation wastewater. The wastewater contains a small amount of lithium carbonate or lithium hydroxide. Due to the low concentration, further lithium extraction cannot be carried out. The conventional treatment process is to simply neutralize and treat it before discharge. This method will cause a waste of lithium resources.

[0004] In view of this, the present utility model is proposed. Utility Model Content

[0005] The utility model aims to provide a treatment device for lithium hydroxide or lithium carbonate lithium precipitation wastewater to solve the above problems.

[0006] In order to achieve the above objectives, the following technical solutions are adopted:

[0007] In a first aspect, the utility model provides a treatment device for lithium hydroxide or lithium carbonate lithium precipitation wastewater, comprising: a collection tank, a pH adjustment system, a first filtering device, a reverse osmosis device, a forward osmosis device, an evaporation concentration device, a neutralization reaction tank, a precipitation separation device and a freezing crystallization device;

[0008] Along the water treatment direction, the collection tank, pH adjustment system, first filtering device, forward osmosis device, evaporation concentration device, neutralization reaction tank and precipitation separation device are connected in sequence;

[0009] The collection pool is used to collect lithium precipitation wastewater and crystallization mother liquor of lithium hydroxide or lithium carbonate;

[0010] The pH adjustment system is used to adjust the pH of the wastewater to 3-9;

[0011] The first filtering device is used to filter the wastewater treated by the pH adjustment system; the first filtering device includes a nanofiltration system; the water outlet of the nanofiltration system is connected to the reverse osmosis device, and the concentrated water outlet of the nanofiltration system is connected to the forward osmosis device;

[0012] The reverse osmosis device is used to purify the produced water of the nanofiltration system to obtain purified water; the concentrated water of the reverse osmosis device is returned to the nanofiltration system for concentration treatment;

[0013] The forward osmosis device is used to concentrate the concentrated water of the nanofiltration system;

[0014] The evaporation concentration device is used to concentrate the concentrated water treated by the forward osmosis device;

[0015] The neutralization reaction tank is used to add sodium carbonate to the wastewater for neutralization reaction;

[0016] The precipitation separation device is used to perform solid-liquid separation on the wastewater treated by the neutralization reaction tank to obtain lithium carbonate and lithium precipitation mother liquor; the lithium precipitation mother liquor is used as the draw liquid of the forward osmosis device;

[0017] The freezing crystallization device is connected to the forward osmosis device and is used to perform freezing crystallization on the drawn liquid treated by the forward osmosis device to obtain sodium sulfate crystals and crystallization mother liquor; the crystallization mother liquor is refluxed to the collection pool.

[0018] As a further technical solution, a second filtering device is also included between the collection tank and the pH adjustment system to remove suspended particles in the wastewater;

[0019] The second filtering device comprises a microfiltration device.

[0020] As a further technical solution, the pH adjustment system is a single-stage, double-stage or three-stage pH adjustment system.

[0021] As a further technical solution, along the water treatment direction, the first filtering device includes a sand filtering device, an ultrafiltration device and a nanofiltration system which are connected in sequence.

[0022] As a further technical solution, the concentrated water from the ultrafiltration device is returned to the collection tank.

[0023] As a further technical solution, the nanofiltration membrane of the nanofiltration system is a high-pressure tubular nanofiltration membrane or a disc-tube nanofiltration membrane.

[0024] As a further technical solution, a chelating resin treatment device is also included between the evaporation concentration device and the neutralization reaction tank to remove impurities in the wastewater.

[0025] As a further technical solution, a lithium precipitation mother liquor pool is further provided between the precipitation separation device and the forward osmosis device, for collecting the lithium precipitation mother liquor and supplying it to the forward osmosis device.

[0026] As a further technical solution, a drying device is also included;

[0027] The drying device is used for drying the sodium sulfate crystals.

[0028] As a further technical solution, the drying device is a fluidized bed.

[0029] Compared with the prior art, the utility model has the following beneficial effects:

[0030] 1) The treatment device provided by the utility model has a simple structure and a reasonable design. Through the coordination between various structures, water can be recycled and lithium in the wastewater can be utilized as a resource;

[0031] 2) The utility model reduces the energy consumption and investment of the evaporator through the cooperation between the nanofiltration system and the reverse osmosis device.

[0032] 3) Through the design of the forward osmosis device, the energy consumption of the evaporation concentration device is effectively reduced, and the overall processing energy consumption is reduced.

[0033] 4) The processing device provided by the utility model has both economic and social benefits and has research and promotion value. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] In order to more clearly illustrate the specific implementation methods of the utility model or the technical solutions in the prior art, the drawings required for use in the specific implementation methods or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some implementation methods of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0035] Figure 1 The processing device provided in Example 1 of the utility model;

[0036] Figure 2 This is a processing device provided in Example 2 of the utility model.

[0037] Icons: 1-collection tank; 2-pH adjustment system; 3-first filtration device; 301-sand filtration device; 302-ultrafiltration device; 303-nanofiltration system; 4-reverse osmosis device; 5-forward osmosis device; 6-evaporation concentration device; 7-neutralization reaction tank; 8-precipitation separation device; 9-freezing crystallization device; 10-second filtration device; 11-chelating resin treatment device; 12-lithium precipitation mother liquor tank; 13-drying device. DETAILED DESCRIPTION

[0038] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. The components of the embodiments of the present application described in the drawings here can be arranged and designed in various different configurations.

[0039] Therefore, the following detailed description of the embodiments of the present application provided in the accompanying drawings is not intended to limit the scope of the present application for which protection is sought, but merely represents selected embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of the present application.

[0040] In the description of the present utility model, it should be noted that the terms "center", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are the directions or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation on the present utility model.

[0041] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms "set", "install", "connect", and "connect" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In the first aspect, the utility model provides a treatment device for lithium hydroxide or lithium carbonate lithium precipitation wastewater, comprising: a collection tank 1, a pH adjustment system 2, a first filtering device 3, a reverse osmosis device 4, a forward osmosis device 5, an evaporation concentration device 6, a neutralization reaction tank 7, a precipitation separation device 8 and a freezing crystallization device 9;

[0043] Along the water treatment direction, the collection tank 1, pH adjustment system 2, first filtering device 3, forward osmosis device 5, evaporation concentration device 6, neutralization reaction tank 7 and precipitation separation device 8 are connected in sequence;

[0044] The collection pool 1 is used to collect lithium hydroxide or lithium carbonate lithium precipitation wastewater and crystallization mother liquor;

[0045] The pH adjustment system 2 is used to adjust the pH of the wastewater to 3-9;

[0046] The first filtering device 3 is used to filter the wastewater treated by the pH adjustment system 2; the first filtering device 3 includes a nanofiltration system 303; the water outlet of the nanofiltration system 303 is connected to the reverse osmosis device 4, and the concentrated water outlet of the nanofiltration system 303 is connected to the forward osmosis device 5;

[0047] The reverse osmosis device 4 is used to purify the produced water of the nanofiltration system 303 to obtain purified water, which can be reused in production; the concentrated water of the reverse osmosis device 4 is returned to the nanofiltration system 303 for concentration treatment;

[0048] The forward osmosis device 5 is used to concentrate the concentrated water of the nanofiltration system 303;

[0049] The evaporation concentration device 6 is used to concentrate the concentrated water treated by the forward osmosis device 5;

[0050] The neutralization reaction tank 7 is used to add sodium carbonate to the wastewater for neutralization reaction;

[0051] The precipitation separation device 8 is used to separate the wastewater treated by the neutralization reaction tank 7 into solid and liquid to obtain lithium carbonate and lithium precipitation mother liquor; the lithium precipitation mother liquor is used as the draw liquid of the forward osmosis device 5;

[0052] The freezing crystallization device 9 is connected to the forward osmosis device 5 and is used to perform freezing crystallization on the drawn liquid treated by the forward osmosis device 5 to obtain sodium sulfate crystals and crystallization mother liquor; the crystallization mother liquor is refluxed to the collection tank 1.

[0053] The treatment device provided by the utility model has a simple structure and a reasonable design. Water can be recycled through the cooperation between various structures, and lithium in the wastewater can be utilized as a resource.

[0054] In some optional embodiments, a second filtering device 10 is further included between the collection tank 1 and the pH adjustment system 2 to remove suspended particles and colloids in the wastewater.

[0055] In some optional embodiments, the second filtering device 10 is a microfiltration device.

[0056] In some optional embodiments, the pH adjustment system 2 is a single-stage, double-stage or three-stage pH adjustment system.

[0057] For example, for wastewater with a pH value above 11, a three-stage pH adjustment system can be used; for wastewater with a pH value of 11, a single-stage or double-stage pH adjustment system can be set up.

[0058] There is no specific limitation on the method for adjusting pH, for example, sulfuric acid or hydrochloric acid may be used for adjustment.

[0059] In some optional embodiments, along the water treatment direction, the first filtering device 3 includes a sand filtration device 301, an ultrafiltration device 302 and a nanofiltration system 303 connected in sequence, which helps to efficiently remove suspended particles in the wastewater and extend the service life of the device.

[0060] In some optional embodiments, the nanofiltration system 303 concentrates the lithium sulfate concentration in the wastewater to 6%-15%.

[0061] In some optional embodiments, the concentrated water from the ultrafiltration device 302 is returned to the collection tank 1, thereby achieving purification and recovery of all water in the wastewater.

[0062] In some optional embodiments, the nanofiltration membrane of the nanofiltration system 303 is a high-pressure tubular nanofiltration membrane or a disc-tube nanofiltration membrane.

[0063] In some optional embodiments, the evaporation concentration device concentrates the lithium sulfate concentration in the wastewater to 20%-30%.

[0064] In some optional embodiments, a chelating resin treatment device 11 is further provided between the evaporation concentration device 6 and the neutralization reaction tank 7 to remove impurities in the wastewater.

[0065] In some optional embodiments, a lithium precipitation mother liquor pool 12 is further included between the precipitation separation device 8 and the forward osmosis device 5 , for collecting the lithium precipitation mother liquor and supplying it to the forward osmosis device 5 .

[0066] In some optional embodiments, a drying device 13 is further included;

[0067] The drying device 13 is used to dry the sodium sulfate crystals.

[0068] In some optional embodiments, the drying device 13 is a fluidized bed.

[0069] The sodium sulphate product is obtained through fluidized bed treatment.

[0070] The present invention is further described below by means of specific examples. However, it should be understood that these examples are only used for more detailed description and should not be understood as limiting the present invention in any form.

[0071] Example 1

[0072] A treatment device for lithium hydroxide or lithium carbonate lithium precipitation wastewater, such as Figure 1 As shown, it includes: a collection tank 1, a pH adjustment system 2, a first filtering device 3, a reverse osmosis device 4, a forward osmosis device 5, an evaporation concentration device 6, a neutralization reaction tank 7, a precipitation separation device 8 and a freezing crystallization device 9;

[0073] Along the water treatment direction, the collection tank 1, pH adjustment system 2, first filtering device 3, forward osmosis device 5, evaporation concentration device 6, neutralization reaction tank 7 and precipitation separation device 8 are connected in sequence;

[0074] The collection pool 1 is used to collect lithium hydroxide or lithium carbonate lithium precipitation wastewater and crystallization mother liquor;

[0075] The pH adjustment system 2 is used to adjust the pH of the wastewater to 3-9;

[0076] The first filtering device 3 is used to filter the wastewater treated by the pH adjustment system 2 to remove suspended particles and colloids in the wastewater; the first filtering device 3 includes a nanofiltration system 303; the nanofiltration system 303 concentrates the lithium sulfate concentration in the wastewater to 6%-15%, the water outlet of the nanofiltration system 303 is connected to the reverse osmosis device 4, and the concentrated water outlet of the nanofiltration system 303 is connected to the forward osmosis device 5;

[0077] The reverse osmosis device 4 is used to purify the produced water of the nanofiltration system 303 to obtain purified water, which can be reused in production; the concentrated water of the reverse osmosis device 4 is returned to the nanofiltration system 303 for concentration treatment;

[0078] The forward osmosis device 5 is used to concentrate the concentrated water of the nanofiltration system 303;

[0079] The evaporation concentration device 6 is used to concentrate the concentrated water treated by the forward osmosis device 5; the evaporation concentration device concentrates the lithium sulfate concentration in the wastewater to 20%-30%;

[0080] The neutralization reaction tank 7 is used to add sodium carbonate to the wastewater for neutralization reaction;

[0081] The precipitation separation device 8 is used to separate the wastewater treated by the neutralization reaction tank 7 into solid and liquid to obtain lithium carbonate and lithium precipitation mother liquor; the lithium precipitation mother liquor is used as the draw liquid of the forward osmosis device 5;

[0082] The freezing crystallization device 9 is connected to the forward osmosis device 5 and is used to perform freezing crystallization on the drawn liquid treated by the forward osmosis device 5 to obtain sodium sulfate crystals and crystallization mother liquor; the crystallization mother liquor is refluxed to the collection tank 1.

[0083] Example 2

[0084] A treatment device for lithium hydroxide or lithium carbonate lithium precipitation wastewater, such as Figure 2As shown, it includes: a collection tank 1, a second filtering device 10, a pH adjustment system 2, a first filtering device 3, a reverse osmosis device 4, a forward osmosis device 5, an evaporation concentration device 6, a chelating resin treatment device 11, a neutralization reaction tank 7, a precipitation separation device 8, a lithium precipitation mother liquor tank 12, a freezing crystallization device 9 and a drying device 13;

[0085] Along the water treatment direction, the collection tank 1, the second filtering device 10, the pH adjustment system 2, the first filtering device 3, the forward osmosis device 5, the evaporation concentration device 6, the chelating resin treatment device 11, the neutralization reaction tank 7 and the precipitation separation device 8 are connected in sequence;

[0086] The collection pool 1 is used to collect lithium hydroxide or lithium carbonate lithium precipitation wastewater and crystallization mother liquor;

[0087] The second filtering device 10 is a microfiltration device, which is used to remove suspended particles in the wastewater.

[0088] The pH adjustment system 2 is a three-stage pH adjustment system, which is used to adjust the pH of the wastewater to 3-9;

[0089] The first filtering device 3 is used to filter the wastewater treated by the pH adjustment system 2 to remove suspended particles and colloids in the wastewater; the first filtering device 3 includes a sand filtering device 301, an ultrafiltration device 302 and a nanofiltration system 303 which are connected in sequence; the concentrated water of the ultrafiltration device 302 is returned to the collection tank 1; the nanofiltration system 303 concentrates the lithium sulfate concentration in the wastewater to 6%-15%, the water outlet of the nanofiltration system 303 is connected to the reverse osmosis device 4, and the concentrated water outlet of the nanofiltration system 303 is connected to the forward osmosis device 5;

[0090] The reverse osmosis device 4 is used to purify the produced water of the nanofiltration system 303 to obtain purified water, which can be reused in production; the concentrated water of the reverse osmosis device 4 is returned to the nanofiltration system 303 for concentration treatment;

[0091] The forward osmosis device 5 is used to concentrate the concentrated water of the nanofiltration system 303;

[0092] The evaporation concentration device 6 is used to concentrate the concentrated water treated by the forward osmosis device 5; the evaporation concentration device concentrates the lithium sulfate concentration in the wastewater to 20%-30%;

[0093] The chelate resin treatment device 11 is used to remove impurities in the wastewater;

[0094] The neutralization reaction tank 7 is used to add sodium carbonate to the wastewater for neutralization reaction;

[0095] The precipitation separation device 8 is used to separate the wastewater treated by the neutralization reaction tank 7 into solid and liquid to obtain lithium carbonate and lithium precipitation mother liquor; the lithium precipitation mother liquor is used as the draw liquid of the forward osmosis device 5;

[0096] The lithium precipitation mother liquor pool 12 is used to collect the lithium precipitation mother liquor and supply it to the forward osmosis device 5;

[0097] The freezing crystallization device 9 is connected to the lithium precipitation mother liquor pool 12, and is used to freeze and crystallize the drawn liquid treated by the forward osmosis device 5 to obtain sodium sulfate crystals and crystallization mother liquor; the crystallization mother liquor is refluxed to the collection pool 1;

[0098] The drying device 13 is a fluidized bed, which is used to dry the obtained sodium sulfate crystals to obtain glauber salt.

[0099] Comparative Example 1

[0100] A treatment device for lithium hydroxide or lithium carbonate precipitation wastewater, which differs from Example 2 in that it does not include a forward osmosis device 5, the concentrate outlet of the nanofiltration system 303 is connected to the evaporation concentration device 6, and the precipitation separation device is connected to the freezing crystallization device 9.

[0101] Test Example 1

[0102] The lithium sulfate concentration in the nanofiltration concentrate is 8%, and the water volume is 10m 3 / h, the amount of water entering the evaporator in comparative example 1 is 10m 3 / h, lithium sulfate concentration 8%, evaporation concentration to 22%, evaporated water volume 6.4m 3 / h, while in Example 2, the nanofiltration concentrate is preferentially fed into the forward osmosis device for pre-concentration to 15%. At this time, the water volume of the concentrate in the forward osmosis device is 5.3m 3 / h, that is, the amount of water entering the evaporator is 5.3m 3 / h, evaporation concentration to 22%, evaporation water volume is 1.7m 3 / h. Compared with comparative example 1, the amount of evaporated water in example 2 is reduced by 4.7m 3 / h, steam energy consumption is reduced by 47% (4.7 / 10=47%).

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the utility model, rather than to limit it. Although the utility model has been described in detail with reference to the aforementioned embodiments, ordinary technicians in this field should understand that they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not make the essence of the corresponding technical solution deviate from the scope of the technical solution of the embodiments of the utility model.

Claims

1. A treatment device for lithium hydroxide or lithium carbonate lithium precipitation wastewater, characterized in that: include: A collection tank (1), a pH adjustment system (2), a first filtering device (3), a reverse osmosis device (4), a forward osmosis device (5), an evaporation concentration device (6), a neutralization reaction tank (7), a precipitation separation device (8) and a freezing crystallization device (9); Along the water treatment direction, the collection tank (1), pH adjustment system (2), first filtering device (3), forward osmosis device (5), evaporation concentration device (6), neutralization reaction tank (7) and precipitation separation device (8) are connected in sequence; The collection pool (1) is used to collect lithium hydroxide or lithium carbonate lithium precipitation wastewater and crystallization mother liquor; The pH adjustment system (2) is used to adjust the pH of the wastewater to 3-9; The first filtering device (3) is used to filter the wastewater treated by the pH adjustment system (2); the first filtering device (3) comprises a nanofiltration system (303); the water outlet of the nanofiltration system (303) is connected to the reverse osmosis device (4), and the concentrated water outlet of the nanofiltration system (303) is connected to the forward osmosis device (5); The reverse osmosis device (4) is used to purify the produced water of the nanofiltration system (303) to obtain purified water; the concentrated water of the reverse osmosis device (4) is returned to the nanofiltration system (303) for concentration treatment; The forward osmosis device (5) is used to concentrate concentrated water from the nanofiltration system (303); The evaporation concentration device (6) is used to concentrate the concentrated water treated by the forward osmosis device (5); The neutralization reaction tank (7) is used to add sodium carbonate to the wastewater for neutralization reaction; The precipitation separation device (8) is used to perform solid-liquid separation on the wastewater treated by the neutralization reaction tank (7) to obtain lithium carbonate and lithium precipitation mother liquor; the lithium precipitation mother liquor is used as the draw liquid of the forward osmosis device (5); The freezing crystallization device (9) is connected to the forward osmosis device (5) and is used to perform freezing crystallization on the drawn liquid treated by the forward osmosis device (5) to obtain sodium sulfate crystals and crystallization mother liquor; the crystallization mother liquor is refluxed to the collection tank (1).

2. The processing device according to claim 1, characterized in that A second filtering device (10) is also provided between the collection tank (1) and the pH adjustment system (2) for removing suspended particles in the wastewater; The second filtering device (10) comprises a microfiltration device.

3. The processing device according to claim 1, characterized in that The pH adjustment system (2) is a single-stage, double-stage or three-stage pH adjustment system.

4. The processing device according to claim 1, characterized in that Along the water treatment direction, the first filtering device (3) comprises a sand filtering device (301), an ultrafiltration device (302) and a nanofiltration system (303) which are connected in sequence.

5. The processing device according to claim 4, characterized in that The concentrated water from the ultrafiltration device (302) flows back to the collection tank (1).

6. The processing device according to claim 1, characterized in that The nanofiltration membrane of the nanofiltration system (303) is a high-pressure tubular nanofiltration membrane or a disc-tube nanofiltration membrane.

7. The processing device according to claim 1, characterized in that A chelating resin treatment device (11) is also provided between the evaporation concentration device (6) and the neutralization reaction tank (7) for removing impurities in the wastewater.

8. The processing device according to claim 1, characterized in that A lithium precipitation mother liquor pool (12) is also provided between the precipitation separation device (8) and the forward osmosis device (5), for collecting the lithium precipitation mother liquor and supplying it to the forward osmosis device (5).

9. The processing device according to claim 1, characterized in that Also includes a drying device (13); The drying device (13) is used to dry the sodium sulfate crystals.

10. The processing device according to claim 9, characterized in that The drying device (13) is a fluidized bed.

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