Fluorine-containing wastewater treatment device

Abstract

The utility model discloses a fluorine-containing wastewater treatment device which comprises a collection tank, a neutralization tank, a membrane tank, a reaction tank, a sedimentation tank and a collection tank which are sequentially arranged, and a drying part is arranged at the rear end of the collection tank; the neutralization tank is provided with an acid-base dosing device, the reaction tank is provided with a lithium chloride dosing device, and the sedimentation tank is a coagulative sedimentation tank. Fluorine is directly recycled from high-concentration fluorine-containing wastewater generated by semiconductor enterprises, so that the fluorine-containing wastewater treatment procedures, cost and secondary pollutants are reduced; recycled products can be used in other industries after being processed, and the problem of fluorine pollution is fundamentally solved.

Description

Technical Field

[0001] The utility model relates to the technical field of fluorine-containing wastewater treatment, in particular to a fluorine-containing wastewater treatment device. Background Art

[0002] Fluoride-containing wastewater in the semiconductor industry refers to wastewater containing fluoride ions generated during the semiconductor manufacturing process. Semiconductor manufacturing is a highly technical process that requires the use of fluoride for steps such as etching and cleaning. The chemicals used in its manufacturing process contain fluoride, such as hydrofluoric acid, which may produce fluoride-containing wastewater during use. Secondly, the detergents and cleaning solvents used in the semiconductor production process also contain fluoride, which react with impurities during the cleaning process to produce fluoride-containing wastewater.

[0003] The characteristics of semiconductor fluoride wastewater are mainly as follows. 1. The concentration of fluoride used in the semiconductor manufacturing process is high, so the concentration of fluoride ions in the wastewater is also correspondingly high. 2. Fluoride is highly corrosive and has a certain corrosive effect on traditional treatment equipment and pipeline materials. 3. Fluoride is toxic to both the human body and the environment. 4. Fluoride is difficult to degrade in the natural environment and will exist in the water for a long time.

[0004] In order to solve the problem of fluoride-containing wastewater in the semiconductor industry, a series of treatment measures can be taken, such as using ion exchange, chemical precipitation, reverse osmosis and defluorination agents to remove fluoride ions from wastewater. Precipitation, ion exchange and other methods all use physical and chemical methods to remove fluoride from sewage in the form of other wastes, and then treat the waste in other forms (such as solid sludge, etc.), without using fluorine as a resource, resulting in a waste of fluorine resources. Fluorine is widely used, especially in the lithium battery industry. Utility Model Content

[0005] The purpose of the utility model is to provide a fluorine-containing wastewater treatment device to solve the problems raised in the above background technology.

[0006] In order to achieve the above purpose, the utility model provides the following technical solutions:

[0007] A fluorine-containing wastewater treatment device comprises a first collecting tank, a neutralization tank, a membrane tank, a reaction tank, a sedimentation tank, and a second collecting tank which are arranged in sequence, wherein a drying part is provided at the rear end of the second collecting tank;

[0008] The neutralization tank is provided with an acid and alkali dosing device, the reaction tank is provided with a lithium chloride dosing device, and the sedimentation tank is a coagulation sedimentation tank.

[0009] As a further solution of the utility model: a main water inlet is provided on the first collecting tank.

[0010] As a further solution of the utility model: a grid pool is provided between the neutralization pool and the membrane pool, and a fine grid is provided in the grid pool.

[0011] As a further solution of the utility model: an immersed ultrafiltration membrane is arranged in the membrane pool, the ultrafiltration membrane is in the form of hollow fiber, the pore size of the ultrafiltration membrane is 0.03-0.08 micron, and the material of the ultrafiltration membrane is polyvinylidene fluoride.

[0012] As a further solution of the utility model: the water outlet of the sedimentation tank is connected to a ceramic membrane device, the concentrated liquid outlet of the ceramic membrane device is connected to the second collecting tank, and a deep defluorination unit is arranged behind the ceramic membrane device.

[0013] As a further solution of the utility model: the drying section includes a washing device, a centrifugal device, and a drying device which are arranged in sequence.

[0014] Compared with the prior art, the beneficial effects of the utility model are:

[0015] 1. This company directly recycles and reuses fluorine from high-concentration fluorine-containing wastewater generated by semiconductor companies, reducing the treatment process, cost and secondary pollutants of fluorine-containing wastewater. The recycled products can be used in other industries after processing, fundamentally solving the problem of fluorine pollution.

[0016] 2. This application adopts the method of adding alkali in the neutralization tank to adjust the pH of the fluoride-containing wastewater to 7-9, which not only removes the influence of hydrogen ions in the water on the precipitation of lithium fluoride, but also produces flocs under alkaline conditions to remove other substances in the water, and can also ensure that the subsequent process sections operate under neutral or weakly alkaline conditions, reduce the anti-corrosion level of the equipment and prevent equipment corrosion;

[0017] 3. The first filtration device of this application adopts submerged ultrafiltration and is arranged in a membrane pool. The membrane adopts the form of hollow fibers, and the composition of the fibers and the distribution of pore sizes are specially designed for difficult-to-treat wastewater. The completely open water inlet channel has a strong impact resistance to high-concentration suspended solids and other influents. The basic pore size of the membrane is 0.03 to 0.08 microns, and the material is polyvinylidene fluoride (PVDF), which has strong oxidative stability. It is resistant to hydrolysis and most acids and alkalis. SS, colloids, etc. can be effectively removed, and the turbidity of the produced water is less than 0.1NTU, reducing the impurities in the recycled raw materials. The cost of the entire system is better than other forms of filtration devices, and it is easy to clean and maintain;

[0018] 4. This application uses a high-efficiency sedimentation tank for solid-liquid separation. No coagulant or flocculant is added here to avoid affecting the recovered material. Most of the lithium fluoride is directly separated in the form of precipitation, and the remaining part enters the next stage in the form of a mixed liquid;

[0019] 5. The membrane device of this application adopts a ceramic membrane system for lithium fluoride concentration and recovery. The ceramic membrane has the following characteristics for lithium fluoride concentration and recovery: the lithium fluoride reuse rate can reach more than 90%, the adopted process route has been verified by long-term operation, and the system reliability is high. The ceramic membrane has the advantages of good chemical stability, acid resistance, alkali resistance, organic solvent resistance, high mechanical strength, backwashing, strong anti-microbial ability, high temperature resistance, narrow pore size distribution, and high separation efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 This is a schematic diagram of the structure of this embodiment;

[0021] Figure 2 This is the process flow chart of this embodiment

[0022] In the figure: 1-first collecting tank, 2-neutralization tank, 3-grid tank, 4-membrane tank, 5-reaction tank, 6-sedimentation tank, 7-ceramic membrane device, 8-second collecting tank, 9-washing device, 10-centrifugal device, 11-drying device, 12-total water inlet. DETAILED DESCRIPTION

[0023] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0024] See also Figure 1-2In the embodiment of the utility model, a fluorine-containing wastewater treatment device comprises a first collecting tank 1, a neutralization tank 2, a grid tank 3, a membrane tank 4, a reaction tank 5, a sedimentation tank 6, a ceramic membrane device 7, and a second collecting tank 8, which are arranged in sequence. The rear end of the second collecting tank 8 is provided with a drying part, and the drying part comprises a washing device 9, a centrifugal device 10, and a drying device 11 arranged in sequence. The collecting tank 1 is provided with a total water inlet 12, and an acid-base dosing device is provided in the neutralization tank 2. A fine grid is provided in the grid tank 3, and a lithium chloride dosing device is provided inside the reaction tank 5. An immersed ultrafiltration membrane is provided in the membrane tank 4, and the ultrafiltration membrane adopts a hollow fiber form. The basic pore size of the ultrafiltration membrane is 0.03 to 0.08 microns, and the material of the ultrafiltration membrane is polyvinylidene fluoride. The sedimentation tank 6 is a high-efficiency coagulation sedimentation tank, and the precipitated lithium fluoride enters the lithium fluoride collection tank 8 through a pipeline. The ceramic membrane device 7 concentrates lithium fluoride through a ceramic membrane system, and the concentrated liquid is connected to the lithium fluoride collection tank 8 through a pipeline. After the collection tank, washing, centrifugation and drying devices are set up. In the washing equipment, pure water at 80℃ to 90℃ is used for washing, and the washing liquid-solid ratio is controlled at 2:1, and the pH is between 6 and 8. After washing, the solid-liquid separation is carried out by a centrifuge. The separated lithium fluoride is dehydrated again through the drying process. The gas high-efficiency sedimentation tank and ceramic membrane device are connected to the lithium fluoride collection tank. A deep defluorination unit is set up after the ceramic membrane device.

[0025] When the utility model is in use, high-concentration fluorine wastewater in the workshop is collected and concentrated into a fluorine-containing wastewater collection pool; the wastewater is pumped into a neutralization pool through a lifting pump in the collection pool, and liquid alkali is added into the neutralization pool to adjust the pH to 7-9; the wastewater is pumped into a fine grid (grid gap ≤1mm) by a pump to remove large impurities, and flows into a membrane pool, in which an immersion ultrafiltration is arranged, and a membrane component made of PVDF material is used to further remove impurities such as SS; the effluent of the membrane component enters a reaction pool, lithium chloride is added into the reaction pool for precipitation reaction, and the mixed liquid enters a high-efficiency precipitation pool for solid-liquid separation; the precipitated solid enters a lithium fluoride collection pool, the supernatant enters a ceramic membrane device for further solid-liquid separation, the concentrated liquid enters a lithium fluoride collection pool, and the clear liquid enters a next deep defluorination unit; the lithium fluoride in the lithium fluoride collection pool is subjected to a washing process to wash out other impurities on the crystal surface and in the concentrated liquid with 20°C ultrapure water; the washed lithium fluoride enters a fluidized bed dryer for drying, and the dried lithium fluoride is packaged.

[0026] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0027] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A fluorine-containing wastewater treatment device, characterized in that: It comprises a first collecting tank (1), a neutralization tank (2), a membrane tank (4), a reaction tank (5), a sedimentation tank (6), and a second collecting tank (8) which are arranged in sequence, wherein a drying section is provided at the rear end of the second collecting tank (8); The neutralization tank (2) is provided with an acid and alkali dosing device, the reaction tank (5) is provided with a lithium chloride dosing device, and the sedimentation tank (6) is a coagulation sedimentation tank; The membrane pool (4) is provided with an immersed ultrafiltration membrane, the ultrafiltration membrane is in the form of a hollow fiber, the pore size of the ultrafiltration membrane is 0.03 to 0.08 microns, and the ultrafiltration membrane is made of polyvinylidene fluoride; The water outlet of the sedimentation tank (6) is connected to a ceramic membrane device (7), the concentrated liquid outlet of the ceramic membrane device (7) is connected to the second collection tank (8), and a deep defluorination unit is arranged behind the ceramic membrane device (7).

2. A fluorine-containing wastewater treatment device according to claim 1, characterized in that: The first collecting pool (1) is provided with a main water inlet (12).

3. A fluorine-containing wastewater treatment device according to claim 1, characterized in that: A grid pool (3) is provided between the neutralization pool (2) and the membrane pool (4), and a fine grid is provided in the grid pool (3).

4. A fluorine-containing wastewater treatment device according to claim 1, characterized in that: The drying section comprises a washing device (9), a centrifugal device (10), and a drying device (11) which are arranged in sequence.

Images