Hydrofluoric acid regeneration method for photovoltaic waste acid

Abstract

Disclosed in the present application is a hydrofluoric acid regeneration method for photovoltaic waste acid. The method comprises the following steps: S1, light component removal, involving: introducing a liquid containing hydrofluoric acid to be treated into a light component removal tower, wherein the tower bottom temperature of the light component removal tower is 100-105°C, and the tower top temperature is 70-80°C, subjecting the liquid to be treated to a light component removal treatment by means of the light component removal tower, discharging the water vapor, which is generated by means of light component removal, via the tower top of the light component removal tower, discharging the generated light component removal liquid, which is generated by means of light component removal, via the tower bottom of the light component removal tower, and introducing same into a first rectification tower; and S2, rectification, involving: the tower bottom temperature of the first rectification tower being 110-115°C, and the tower top temperature being 98-105°C, rectifying the generated light component removal liquid by means of the first rectification tower, discharging HF and water vapor, which are generated by means of rectification, via the tower top of the first rectification tower, condensing same to form hydrofluoric acid, and discharging the distillate, which is generated by means of rectification, via the tower bottom of the first rectification tower. By means of the present application, hydrofluoric acid in the hydrofluoric acid waste liquid can be recycled, and compared with the prior art, the situation where fluorine resources are wasted is effectively avoided.

Description

Hydrofluoric acid regeneration method for photovoltaic waste acid Technical Field

[0001] The present invention relates to the technical field of photovoltaic industry pickling waste liquid treatment, and in particular to a hydrofluoric acid regeneration method for photovoltaic waste acid. Background Art

[0002] Photovoltaic solar energy is a new application technology that utilizes the photovoltaic effect of solar cell semiconductor materials to convert sunlight into electrical energy. During the solar cell manufacturing process, silicon wafers are immersed in a cleaning tank filled with hydrofluoric acid to remove surface impurities such as oxide layers, particulate matter, and metal ions. Since the concentration and purity of hydrofluoric acid decrease over time, and the cleaning effect also declines, the solution must be replaced regularly.

[0003] Hydrofluoric acid waste liquid is highly corrosive, toxic and environmentally polluting. The hydrofluoric acid waste liquid discharged from the cleaning tank is usually discharged into the wastewater or waste acid treatment system for centralized treatment. There are many methods for treating hydrofluoric acid waste liquid, among which chemical precipitation is the simplest and most effective. The chemical precipitation method is to remove fluoride ions by adding calcium salts such as calcium oxide, calcium chloride, lime milk, and carbide slag to the hydrofluoric acid waste liquid, and the fluoride ions react with calcium ions to form insoluble calcium fluoride precipitates. Since hydrofluoric acid waste liquid contains a large amount of fluorine resources, if chemical precipitation is used, a large amount of fluorine resources will be converted into sludge with no economic value. Obviously, this chemical precipitation method cannot recycle hydrofluoric acid waste liquid, which not only causes a waste of fluorine resources, but also poses a risk of secondary pollution. Summary of the Invention

[0004] One advantage of the present invention is that it provides a hydrofluoric acid regeneration method for photovoltaic waste acid. The present invention can recycle the hydrofluoric acid in the hydrofluoric acid waste liquid, and compared with the existing technology, it effectively avoids the waste of fluorine resources.

[0005] One advantage of the present invention is that it provides a method for regenerating hydrofluoric acid from photovoltaic waste acid. The present invention can circulate and treat the hydrofluoric acid formed by condensation of HF and water vapor produced by two distillations, greatly improving the recovery rate of hydrofluoric acid waste liquid, so that the hydrofluoric acid recovery rate reaches more than 90%, reducing the HF content in the discharged wastewater, and reducing the cost of wastewater treatment. Compared with the existing technology, not only is the recovery rate higher, but the process is simpler, the discharge of waste residue and wastewater is greatly reduced, and the economic and environmental benefits are obvious.

[0006] One advantage of the present invention is that it provides a hydrofluoric acid regeneration method for photovoltaic waste acid. The present invention can generate water vapor during the process of recovering hydrofluoric acid, and the water vapor can be condensed to form water to achieve water recovery, thereby reducing wastewater production.

[0007] One advantage of the present invention is that it provides a method for regenerating hydrofluoric acid from photovoltaic waste acid. After light removal, the present invention adsorbs water formed by condensation of water vapor generated by light removal to obtain ultrapure water.

[0008] One advantage of the present invention is that it provides a method for regenerating hydrofluoric acid for photovoltaic waste acid. After a primary distillation, the present invention adsorbs the hydrofluoric acid formed by condensation of HF and water vapor generated in the primary distillation to obtain UPS electronic grade hydrofluoric acid.

[0009] One advantage of the present invention is that it provides a hydrofluoric acid regeneration method for photovoltaic waste acid. The present invention can treat hydrofluoric acid waste liquid, fully utilize the heat generated during the treatment process through heat transfer and mass transfer, realize the comprehensive utilization of thermal energy, and effectively save energy consumption.

[0010] To achieve at least one of the above advantages of the present invention, the present invention provides a method for regenerating hydrofluoric acid from photovoltaic waste acid, comprising the following steps:

[0011] S1, light removal: a liquid to be treated containing hydrofluoric acid is introduced into the light removal tower, the bottom temperature of the light removal tower is 100-105°C and the top temperature is 70-80°C, the light removal tower is used to remove light from the liquid to be treated, the water vapor generated by the light removal is discharged from the top of the light removal tower, and the light removal product liquid generated by the light removal is discharged from the bottom of the light removal tower and introduced into the first distillation tower;

[0012] S2. Distillation: The bottom temperature of the first distillation tower is 110-115°C and the top temperature is 98-105°C. The first distillation tower distills the light-removed liquid. HF and water vapor produced by the distillation are discharged from the top of the first distillation tower and condensed to form hydrofluoric acid. The distillate produced by the distillation is discharged from the bottom of the first distillation tower.

[0013] According to one embodiment of the present invention, the following steps are further included before step S1:

[0014] Material introduction: The hydrofluoric acid waste liquid in the cleaning tank is introduced into the pretreatment component through a high-purity pipeline, and the pretreatment component introduces the liquid to be treated containing hydrofluoric acid into the light removal tower.

[0015] According to one embodiment of the present invention, the following steps are included:

[0016] The hydrofluoric acid waste liquid in the cleaning tank is introduced into the mixer of the pretreatment component through a high-purity pipeline. The mixer mixes the hydrofluoric acid waste liquid with a predetermined amount of hydrogen peroxide to form a liquid to be treated.

[0017] According to an embodiment of the present invention, the following steps are also included:

[0018] The pretreatment component includes a reactor, wherein a spraying member and a catalytic layer are provided in the reactor, the reactor forms a reaction chamber, the catalytic layer is installed in the reaction chamber, the spraying member is installed above the catalytic layer, and the spraying member is configured to spray ozone into the reaction chamber, high-purity water is introduced into the reaction chamber formed by the reactor, and the high-purity water and ozone generate active oxygen groups under the action of the catalyst, so that low-valent metal ions are oxidized into high-valent metal ions by the active oxygen groups.

[0019] According to an embodiment of the present invention, the following steps are also included:

[0020] The hydrofluoric acid waste liquid discharged from the cleaning tank is filtered through a filter before being introduced into the pretreatment component to remove solid impurities in the hydrofluoric acid waste liquid.

[0021] According to one embodiment of the present invention, the following steps are further included after step S2:

[0022] Secondary distillation and reflux: The distillate discharged from the bottom of the first distillation tower is introduced into the second distillation tower. The bottom temperature of the second distillation tower is 108-120°C and the top temperature is 98-105°C. The distillate is distilled by the second distillation tower. The HF and water vapor generated by the distillation are discharged from the top of the second distillation tower and condensed to form hydrofluoric acid. After entering the pretreatment component through a high-purity pipeline for circulation treatment, the wastewater generated by the distillation is discharged from the bottom of the second distillation tower.

[0023] According to an embodiment of the present invention, the following steps are also included:

[0024] The distillate discharged from the bottom of the first distillation tower is introduced into a first transfer tank for storage. After the distillate in the first transfer tank reaches a predetermined amount, the distillate is guided from the first transfer tank to the second distillation tower.

[0025] According to an embodiment of the present invention, the following steps are also included:

[0026] The hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the second distillation tower is introduced into a second transfer tank for storage. The hydrofluoric acid can be guided to the pretreatment assembly from the second transfer tank.

[0027] According to one embodiment of the present invention, the following steps are included:

[0028] The first adsorber adsorbs water formed by condensation of water vapor discharged from the top of the light removal tower to remove metal ions in the water;

[0029] The water treated by the first adsorber is introduced into a water storage tank for water recovery.

[0030] According to an embodiment of the present invention, the following steps are also included:

[0031] The second adsorber adsorbs hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the first distillation tower to remove metal ions in the hydrofluoric acid;

[0032] The hydrofluoric acid treated by the second adsorber is introduced into a product storage tank for hydrofluoric acid recovery.

[0033] Compared with the prior art, the hydrofluoric acid regeneration equipment for photovoltaic waste acid of the present invention has the following technical effects:

[0034] 1. The mixer of the present invention mixes hydrofluoric acid waste liquid and a predetermined amount of hydrogen peroxide to form a liquid to be treated, and then the light removal tower removes light to produce water vapor and light removal liquid. Since hydrogen peroxide reacts with metal ions in the hydrofluoric acid waste liquid to produce high boiling points, the content of metal ions in the water vapor generated by light removal is reduced to recover water with higher purity formed by condensation of the water vapor.

[0035] 2. The first distillation tower of the present invention distills the light-removal product liquid produced by light-removal to produce HF, water vapor and distillate, thereby realizing a single distillation, and recovers the hydrofluoric acid formed by the condensation of HF and water vapor to recycle the hydrofluoric acid in the hydrofluoric acid waste liquid.

[0036] 3. The present invention is based on a light fraction removal operation and a primary distillation operation. The second distillation tower distills the distillate to produce HF, water vapor, and wastewater. By directing the hydrofluoric acid formed by condensing HF and water vapor to the pretreatment component for recycling treatment, the recovery rate of the hydrofluoric acid waste liquid is greatly improved, and the hydrofluoric acid recovery rate reaches more than 90%.

[0037] 4. The first adsorber of the present invention adsorbs water formed by condensation of water vapor generated by light removal to remove metal ions in the water, thereby ensuring that the obtained water is ultrapure water.

[0038] 5. The second adsorber of the present invention adsorbs the hydrofluoric acid formed by condensing HF and water vapor produced by the primary condensation to remove metal ions in the hydrofluoric acid, thereby ensuring that the obtained hydrofluoric acid meets the UPS electronic grade hydrofluoric acid standard. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] FIG1 shows a schematic structural diagram of a hydrofluoric acid regeneration device for photovoltaic waste acid according to the present invention.

[0040] Reference numerals:

[0041] Pretreatment component 10; mixer 11; intermediate storage tank 12;

[0042] Lightness removal tower 20;

[0043] Distillation assembly 30; first distillation tower 31; second distillation tower 32;

[0044] Transfer tank group 40; first transfer tank 41; second transfer tank 42;

[0045] Adsorption assembly 50; first adsorber 51; second adsorber 52;

[0046] Storage tank group 60; water storage tank 61; product storage tank 62;

[0047] Filter 70. DETAILED DESCRIPTION

[0048] The following description is intended to disclose the present invention so that those skilled in the art can implement the present invention. The preferred embodiments described below are for illustrative purposes only, and those skilled in the art will readily appreciate other obvious variations. The basic principles of the present invention defined in the following description may be applied to other embodiments, variations, improvements, equivalents, and other technical solutions that do not depart from the spirit and scope of the present invention.

[0049] Those skilled in the art should understand that, in the disclosure of the present invention, the terms "longitudinal", "transverse", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like to indicate orientations or positional relationships are based on the orientations or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, the above terms should not be understood as limiting the present invention.

[0050] It is to be understood that the term "one" should be understood as "at least one" or "one or more", that is, in one embodiment, the number of an element may be one, while in another embodiment, the number of the elements may be multiple, and the term "one" should not be understood as a limitation on the quantity.

[0051] With reference to FIG1 , a hydrofluoric acid regeneration device for photovoltaic waste acid according to a preferred embodiment of the present invention will be described in detail below. The hydrofluoric acid regeneration device for photovoltaic waste acid includes a pretreatment component 10, which is connected to a cleaning tank through a high-purity pipeline, and the cleaning tank can introduce hydrofluoric acid waste liquid into the pretreatment component 10.

[0052] The hydrofluoric acid regeneration equipment for photovoltaic waste acid includes a light-removal tower 20. The pretreatment component 10 is connected to the light-removal tower 20 through a high-purity pipeline. The pretreatment component 10 can pass the liquid to be treated containing hydrofluoric acid into the light-removal tower 20. The bottom temperature of the light-removal tower 20 is 100-105°C and the top temperature is 70-80°C. Based on the characteristic that the azeotropic point of HF and water in the hydrofluoric acid waste liquid is higher than the boiling point of water, the light-removal tower 20 can remove light from the liquid to be treated to discharge the water vapor generated by the light-removal treatment from its top and discharge the light-removal product containing hydrofluoric acid from its bottom, so as to utilize the light-removal tower 20 to reduce the moisture in the liquid to be treated.

[0053] Preferably, the liquid to be treated is introduced from the upper end of the lightness removal tower 20. In this way, as the water vapor in the lightness removal tower 20 rises and is discharged from the top of the tower, the liquid to be treated flowing downward in the lightness removal tower 20 contacts the rising water vapor, conducting mass and heat transfer. Part of the heat of the water vapor is absorbed by the liquid to be treated, thereby facilitating the lightness removal operation, saving energy consumption of the lightness removal tower 20, and utilizing the heat of the water vapor. In addition, the liquid to be treated acts as a refrigerant to cool the water vapor to promote its condensation for subsequent recovery, thereby achieving comprehensive utilization of thermal energy.

[0054] Preferably, the bottom pressure of the lightness removal tower 20 is 0.09-0.11 MPa, the top pressure is 0.09-0.1 MPa, and the reflux ratio is controlled at 0.28-0.35. By controlling the pressure and temperature, more water vapor can be effectively discharged from the top of the tower.

[0055] The hydrofluoric acid regeneration equipment for photovoltaic waste acid also includes a distillation component 30, which includes a first distillation tower 31. The bottom of the light removal tower 20 is connected to a high-purity pipeline and is in communication with the first distillation tower 31 through the high-purity pipeline. The light removal tower 20 can introduce light removal product liquid into the first distillation tower 31. The bottom temperature of the first distillation tower 31 is 110-115°C to reach above the azeotropic point of HF and water, and the top temperature is 98-105°C. The first distillation tower 31 can distill the light removal product liquid to discharge HF and water vapor generated by the distillation treatment from its top and discharge a distillate containing hydrofluoric acid from its bottom to achieve a single distillation, wherein HF and water vapor can be condensed to form hydrofluoric acid, so as to recycle the hydrofluoric acid in the hydrofluoric acid waste liquid. Compared with the existing technology, it effectively avoids the waste of fluorine resources.

[0056] Preferably, the light-removal product liquid is introduced into the upper end of the first distillation tower 31. In this way, as the HF and water vapor rise within the first distillation tower 31 and are discharged from the top, the light-removal product liquid flowing downstream within the first distillation tower 31 contacts the rising HF and water vapor, allowing mass and heat transfer. Part of the heat from the HF and water vapor is absorbed by the light-removal product liquid, facilitating a single distillation operation, saving energy consumption in the first distillation tower 31, and utilizing the heat from the HF and water vapor. Furthermore, the light-removal product liquid acts as a refrigerant to cool the HF and water vapor to promote their condensation for subsequent recovery, achieving comprehensive utilization of thermal energy.

[0057] Preferably, the bottom pressure of the first distillation tower 31 is 0.09-0.11 MPa, and the top pressure is 0.09-0.11 MPa. By controlling the pressure and temperature, HF and water vapor can be effectively discharged in a predetermined ratio, so that the concentration of the generated hydrofluoric acid can be directly used for cleaning solar cells.

[0058] In a preferred embodiment, by detecting the concentration of the hydrofluoric acid discharged from the first distillation tower 31, such as by using an acidity detector to detect the concentration of the hydrofluoric acid discharged from the first distillation tower 31, it can be determined whether the concentration of the hydrofluoric acid discharged from the first distillation tower 31 meets the concentration requirement for subsequent cleaning of solar cells.

[0059] Furthermore, based on the detected concentration of the hydrofluoric acid discharged from the first distillation tower 31, the bottom pressure and the top pressure of the first distillation tower 31 are automatically regulated by a controller to be between 0.09 and 0.11 MPa. In a variant embodiment, based on the detected concentration of the hydrofluoric acid discharged from the first distillation tower 31, the bottom pressure and the top pressure of the lightness removal tower 20 are automatically regulated by a controller, thereby ensuring that the concentration of the hydrofluoric acid distilled from the first distillation tower 31 is sufficient for direct use in cleaning solar cells.

[0060] Those skilled in the art will appreciate that the gas pressure generator for regulating the pressure of the bottom and top of the first distillation tower 31 and / or the bottom and top of the lightness removal tower 20 is controllably connected to the controller.

[0061] The distillation assembly 30 also includes a second distillation tower 32. The bottom of the first distillation tower 31 is connected to a high-purity pipeline and is connected to the second distillation tower 32 through a high-purity pipeline. The first distillation tower 31 can introduce distillate into the second distillation tower 32. The bottom temperature of the second distillation tower 32 is 108-120°C, and the top temperature is 98-105°C. The second distillation tower 32 can distill the distillate to discharge HF and water vapor generated by the distillation process from its top and discharge wastewater from its bottom to achieve secondary distillation. In this way, based on the distillation of the light-removed liquid by the first distillation tower 31, the second distillation tower 32 further distills the distillate discharged from the bottom of the first distillation tower 31, reducing the HF content in the discharged wastewater and reducing the cost of wastewater treatment.

[0062] It is worth mentioning that the concentration of hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the second distillation tower 32 is relatively low. The top of the second distillation tower 32 is connected to a high-purity pipeline and is connected to the pretreatment component 10 through the high-purity pipeline, so that the hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the second distillation tower 32 can be introduced into the pretreatment component 10 to form a circulating treatment. At this time, the hydrofluoric acid recovery rate reaches more than 90%. Compared with the existing technology, there is no need to discharge the hydrofluoric acid waste liquid into the mixed acid system and then recover the hydrofluoric acid through a more complex process. The recovery rate of the hydrofluoric acid waste liquid is higher, which greatly reduces the discharge of waste residue and wastewater, and has obvious economic and environmental benefits.

[0063] Preferably, the distillate is introduced into the upper end of the second distillation column 32. As the HF and water vapor rise within the second distillation column 32 and are discharged from the top, the distillate flowing downward from the second distillation column 32 comes into contact with the HF and water vapor, allowing for mass and heat transfer. Part of the heat from the HF and water vapor is absorbed by the distillate, facilitating the secondary distillation operation. This saves energy in the second distillation column 32 and allows the heat from the HF and water vapor to be utilized. Furthermore, the distillate acts as a refrigerant to cool the HF and water vapor, promoting their condensation for subsequent recovery, achieving comprehensive thermal energy utilization.

[0064] Preferably, the bottom pressure of the second distillation tower 32 is 0.09-0.11 MPa, and the top pressure is 0.09-0.11 MPa.

[0065] The pretreatment assembly 10 includes a mixer 11, which is connected to the cleaning tank via a high-purity pipeline. The mixer 11 can be introduced with a predetermined amount of hydrogen peroxide and mixes the hydrofluoric acid waste liquid discharged from the cleaning tank with the hydrogen peroxide to form a liquid to be treated, wherein the low-valent arsenic compounds in the hydrofluoric acid waste liquid are oxidized and converted into high-valent high-boiling arsenic compounds as heavy components. The light removal tower 20 removes light from the liquid to be treated, so that the bottom of the tower discharges a light removal product containing hydrofluoric acid and high-boiling compounds. The first rectifying tower 31 rectifys the light removal product so that the bottom of the tower discharges a distillate containing hydrofluoric acid and high-boiling compounds. The second rectifying tower 32 rectifys the distillate so that the bottom of the tower discharges wastewater containing high-boiling compounds.

[0066] Preferably, the mass ratio of the hydrogen peroxide mixed in the mixer 11 to HF in the hydrofluoric acid waste liquid is 0.2-1.5%.

[0067] 0046. The pretreatment assembly 10 also includes an intermediate storage tank 12. The mixer 11 is connected to the intermediate storage tank 12 via a high-purity pipeline. The mixer 11 can introduce the liquid to be treated into the intermediate storage tank 12. The intermediate storage tank 12 is used to store the liquid to be treated. The intermediate storage tank 12 is connected to the lightness removal tower 20 via a high-purity pipeline. The intermediate storage tank 12 can introduce the liquid to be treated into the lightness removal tower 20. In this way, the liquid to be treated after being mixed by the mixer 11 is introduced into the intermediate storage tank 12 to free up space for the mixer 11 to carry out the next round of mixing.

[0068] More preferably, the pretreatment assembly 10 includes a reactor, wherein a spraying member and a catalytic layer are provided in the reactor, the reactor forms a reaction chamber, and the catalytic layer is installed in the reaction chamber. The spraying member 322 is installed above the catalytic layer, and the spraying member is configured to spray ozone into the reaction chamber. High-purity water is introduced into the reaction chamber formed by the reactor, and the high-purity water and ozone generate active oxygen groups, such as OH groups, under the action of the catalyst. - 、O2 - The reactor is connected to the mixer via a pipeline, so that the liquid containing active oxygen groups discharged from the reaction device is passed into the mixer. Low-valent metal ions in the waste acid liquid passed into the mixer are oxidized by the active oxygen groups into high-valent metal ions.

[0069] It is worth mentioning that the active oxygen groups generated in the pretreatment component 10 have stronger oxidizing ability than oxidants such as potassium permanganate and hydrogen peroxide, so that the metal ions in the waste acid liquid can be fully oxidized, so that the metal ions oxidized into high-valent metal ions can flow with the liquid phase to the recovery device, so that the water vapor flowing out of the gas phase from the de-light tower 20 and the hydrofluoric acid gas flowing out of the first distillation tower 31 and the second distillation tower 32 do not contain metal ions, and then the device can extract high-purity water and electronic-grade hydrofluoric acid that can be directly used for subsequent cleaning of solar cells without setting up an adsorption tower.

[0070] Preferably, the second distillation tower 32 is connected to the intermediate storage tank 12 through a high-purity pipeline, so that the hydrofluoric acid discharged from the top of the second distillation tower 32 and formed by condensation can be introduced into the intermediate storage tank 12 for circulation treatment.

[0071] Preferably, the mass fraction of HF in the light-removal liquid discharged from the bottom of the light-removal tower 20 is controlled at 30-40%, so that the HF and water vapor distilled from the first distillation tower 31 can be discharged in a predetermined ratio.

[0072] The hydrofluoric acid regeneration equipment for photovoltaic waste acid also includes a transfer tank group 40, which includes a first transfer tank 41. The first transfer tank 41 is installed on the high-purity pipeline between the first distillation tower 31 and the second distillation tower 32. The first transfer tank 41 is used to store the distillate discharged from the bottom of the first distillation tower 31. The first transfer tank 41 can introduce the distillate into the second distillation tower 32.

[0073] It is worth mentioning that since the distillate produced by the distillation treatment in the first distillation tower 31 is small, the first transfer tank 41 is used to store the distillate discharged from the first distillation tower 31 in real time, and after the distillate reaches a certain amount, it is introduced into the second distillation tower 32, so that the second distillation tower 32 can perform intermittent distillation to save processing costs.

[0074] The transfer tank group 40 also includes a second transfer tank 42, which is installed on the high-purity pipeline between the second distillation tower 32 and the pretreatment component 10. The second transfer tank 42 is used to store hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the second distillation tower 32. The second transfer tank 42 can introduce hydrofluoric acid into the pretreatment component 10.

[0075] It is worth mentioning that due to the aggregation effect of the first transfer tank 41 on the distillate, after the second distillation tower 32 performs the distillation operation, more HF and water vapor are discharged from the top of the second distillation tower 32, so that the second transfer tank 42 stores more condensed hydrofluoric acid, so as to supply hydrofluoric acid to the pretreatment component 10 considering the actual space capacity of the pretreatment component 10.

[0076] Preferably, the second transfer tank 42 is installed on the high-purity pipeline between the second distillation tower 32 and the intermediate storage tank 12, so that the hydrofluoric acid treated and condensed by the distillation component 30 can be processed again, thereby improving the recovery rate of the hydrofluoric acid waste liquid.

[0077] The hydrofluoric acid regeneration equipment for photovoltaic waste acid includes an adsorption component 50, and the adsorption component 50 includes a first adsorber 51. The top of the de-lightening tower 20 is connected to a high-purity pipeline and communicates with the first adsorber 51 through the high-purity pipeline. The first adsorber 51 is used to remove metal ions in water formed by condensation of water vapor discharged from the top of the de-lightening tower 20, so that the recovered water is ultrapure water.

[0078] Preferably, the first adsorber 51 is filled with an ion exchange resin having a particle size of 10 to 20 meshes.

[0079] The adsorption assembly 50 also includes a second adsorber 52. The top of the first distillation tower 31 is connected to a high-purity pipeline and communicates with the second adsorber 52 through the high-purity pipeline. The second adsorber 52 is used to remove metal ions in the hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the first distillation tower 31, so as to improve the purity of the hydrofluoric acid and ensure that the obtained hydrofluoric acid meets the UPS electronic grade hydrofluoric acid standard.

[0080] Preferably, the second adsorber 52 is filled with an ion exchange resin having a particle size of 10 to 20 meshes.

[0081] The hydrofluoric acid regeneration equipment for photovoltaic waste acid includes a storage tank group 60, and the storage tank group 60 includes a water storage tank 61. The water storage tank 61 is connected to the first adsorber 51 through a high-purity pipeline. The water storage tank 61 is used to collect water discharged by adsorption by the first adsorber 51.

[0082] The storage tank group 60 further includes a product storage tank 62 , which is connected to the second adsorber 52 via a high-purity pipeline. The product storage tank 62 is used to collect the hydrofluoric acid discharged after adsorption by the second adsorber 52 .

[0083] Preferably, the hydrofluoric acid regeneration equipment for photovoltaic waste acid further includes a filter 70, which is installed on the high-purity pipeline between the mixer 11 and the cleaning tank, and is used to remove solid impurities in the hydrofluoric acid waste liquid.

[0084] Preferably, the pore size of the filter 70 is 0.01-0.05 μm.

[0085] In one embodiment, the temperature of the hydrofluoric acid waste liquid discharged from the cleaning tank is 25° C. The treated liquid formed by mixing the hydrofluoric acid waste liquid with hydrogen peroxide contains hydrofluoric acid and high-boiling substances such as fluorosilicic acid, wherein the HF content is 10%, the water content is 89.8%, the high-boiling substance content is 0.2%, and the mass ratio of hydrogen peroxide to HF in the hydrofluoric acid waste liquid is 1%. The treated liquid formed by mixing the hydrofluoric acid waste liquid with hydrogen peroxide is introduced into the lightness removal column 20 at a flow rate of 30 kg / h. The bottom temperature of the lightness removal column 20 is 100-103° C., the top temperature is 75-80° C., the bottom pressure is 0.09-0.11 MPa, the top pressure is 0.09-0.1 MPa, the reflux ratio is controlled at 0.28-0.35, and the ultrapure water recovery rate is approximately 21.4 kg / h.

[0086] The bottom temperature of the first distillation tower 31 is 110-115°C, the top temperature is 98-102°C, the bottom pressure is 0.09-0.11 MPa, the top pressure is 0.09-0.11 MPa, the reflux ratio is controlled at 0.45-0.55, the HF content in the hydrofluoric acid discharged and condensed from the top of the tower is 34.5-35.5wt%, and the flow rate of the distillate discharged from the bottom of the first distillation tower 31 is about 0.086 kg / h, and the HF content in the distillate is 21.5-22.5wt%.

[0087] The bottom temperature of the second distillation tower 32 is 108-120°C, the top temperature is 98-105°C, the bottom pressure is 0.09-0.11 MPa, the top pressure is 0.09-0.11 MPa, and the reflux ratio is controlled at 0.4-0.6. The HF content in the hydrofluoric acid discharged and condensed from the top of the tower is 31.5-32.5 wt%. The HF content in the wastewater discharged from the bottom of the second distillation tower 32 is less than 3 wt%. Calculations show that the hydrofluoric acid recovery rate exceeds 90%, and only 1 kg of wastewater is generated for every 2500 kg of hydrofluoric acid waste liquid processed.

[0088] This application also proposes a hydrofluoric acid regeneration method for photovoltaic waste acid, comprising the following steps:

[0089] S1, light removal: the light removal tower 20 is introduced into the liquid to be treated containing hydrofluoric acid, the bottom temperature of the light removal tower 20 is 100-105°C and the top temperature is 70-80°C, the light removal tower 20 is used to remove light from the liquid to be treated, the water vapor generated by the light removal is discharged from the top of the light removal tower 20, and the light removal product generated by the light removal is discharged from the bottom of the light removal tower 20 and introduced into the first distillation tower 31;

[0090] S2. Distillation: The bottom temperature of the first distillation tower 31 is 110-115° C. and the top temperature is 98-105° C. The first distillation tower 31 distills the light-removed liquid. HF and water vapor produced by the distillation are discharged from the top of the first distillation tower 31 and condensed to form hydrofluoric acid. The distillate produced by the distillation is discharged from the bottom of the first distillation tower 31.

[0091] The hydrofluoric acid regeneration method for photovoltaic waste acid further comprises the following steps before step S1:

[0092] S3, material introduction: the hydrofluoric acid waste liquid in the cleaning tank is introduced into the pretreatment component 10 through a high-purity pipeline, and the pretreatment component 10 introduces the liquid to be treated containing hydrofluoric acid into the lightness removal tower 20.

[0093] The hydrofluoric acid regeneration method for photovoltaic waste acid further comprises the following steps after step S2:

[0094] S4. Secondary distillation and reflux: The distillate discharged from the bottom of the first distillation tower 31 is introduced into the second distillation tower 32. The bottom temperature of the second distillation tower 32 is 108-120°C and the top temperature is 98-105°C. The distillate is distilled by the second distillation tower 32. HF and water vapor produced by the distillation are discharged from the top of the second distillation tower 32 and condensed to form hydrofluoric acid. After that, they enter the pretreatment component 10 through a high-purity pipeline for recycling treatment. The wastewater produced by the distillation is discharged from the bottom of the second distillation tower 32.

[0095] Preferably, step S3 includes the following steps:

[0096] The hydrofluoric acid waste liquid in the cleaning tank is introduced into the mixer 11 through a high-purity pipeline. The mixer 11 mixes the hydrofluoric acid waste liquid with a predetermined amount of hydrogen peroxide to form a liquid to be treated.

[0097] Preferably, in step S3, the following steps are further included:

[0098] The mixer 11 introduces the liquid to be treated into the intermediate storage tank 12 , and then the liquid to be treated is introduced into the light removal tower 20 from the intermediate storage tank 12 .

[0099] Preferably, in step S3, the following steps are further included:

[0100] The hydrofluoric acid waste liquid discharged from the cleaning tank is filtered through the filter 70 before being introduced into the pretreatment component 10 to remove solid impurities in the hydrofluoric acid waste liquid.

[0101] Preferably, step S1 includes the following steps:

[0102] The first adsorber 51 adsorbs water formed by condensation of water vapor discharged from the top of the lightness removal tower 20 to remove metal ions in the water.

[0103] Preferably, in step S1, the following steps are further included:

[0104] The water treated by the first adsorber 51 is introduced into the water storage tank 61 for water recovery.

[0105] Preferably, step S2 includes the following steps:

[0106] The second adsorber 52 adsorbs hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the first distillation tower 31 to remove metal ions in the hydrofluoric acid.

[0107] Preferably, in step S2, the following steps are further included:

[0108] The hydrofluoric acid treated by the second adsorber 52 is introduced into the product storage tank 62 for hydrofluoric acid recovery.

[0109] Preferably, between step S2 and step S4, the following steps are further included:

[0110] The distillate discharged from the bottom of the first distillation tower 31 is introduced into the first transfer tank 41 for storage. After the distillate in the first transfer tank 41 reaches a predetermined amount, the distillate is guided from the first transfer tank 41 to the second distillation tower 32 .

[0111] Preferably, in step S4, the following steps are further included:

[0112] The hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the second distillation tower 32 is introduced into the second transfer tank 42 for storage. The hydrofluoric acid can be guided to the pretreatment assembly 10 from the second transfer tank 42 .

[0113] Those skilled in the art will appreciate that the embodiments of the present invention described above and shown in the accompanying drawings are intended to be illustrative only and are not intended to limit the present invention. The advantages of the present invention have been fully and effectively achieved. The functional and structural principles of the present invention have been demonstrated and illustrated in the embodiments. Any variations or modifications may be made to the embodiments of the present invention without departing from the principles described.

Claims

1. A method for regenerating hydrofluoric acid from photovoltaic waste acid, characterized in that: The steps include: S1, light removal: a liquid to be treated containing hydrofluoric acid is introduced into the light removal tower, the bottom temperature of the light removal tower is 100-105°C and the top temperature is 70-80°C, the light removal tower is used to remove light from the liquid to be treated, the water vapor generated by the light removal is discharged from the top of the light removal tower, and the light removal product liquid generated by the light removal is discharged from the bottom of the light removal tower and introduced into the first distillation tower; S2, distillation: the bottom temperature of the first distillation tower is 110-115°C and the top temperature is 98-105°C. The first distillation tower distills the light-removed liquid. HF and water vapor produced by the distillation are discharged from the top of the first distillation tower and condensed to form hydrofluoric acid. The distillate produced by the distillation is discharged from the bottom of the first distillation tower. Secondary distillation and reflux: The distillate discharged from the bottom of the first distillation tower is introduced into the second distillation tower. The bottom temperature of the second distillation tower is 108-120°C and the top temperature is 98-105°C. The distillate is distilled by the second distillation tower. The HF and water vapor generated by the distillation are discharged from the top of the second distillation tower and condensed to form hydrofluoric acid. After entering the pretreatment component through a high-purity pipeline for circulation treatment, the wastewater generated by the distillation is discharged from the bottom of the second distillation tower.

2. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 1, characterized in that: The following steps are also included before step S1: Material introduction: The hydrofluoric acid waste liquid in the cleaning tank is introduced into the pretreatment component through a high-purity pipeline, and the pretreatment component introduces the liquid to be treated containing hydrofluoric acid into the light removal tower.

3. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 2, characterized in that: The steps include: The hydrofluoric acid waste liquid in the cleaning tank is introduced into the mixer of the pretreatment component through a high-purity pipeline. The mixer mixes the hydrofluoric acid waste liquid with a predetermined amount of hydrogen peroxide to form a liquid to be treated.

4. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 3, characterized in that: The following steps are also included: The pretreatment component includes a reactor, wherein a spraying member and a catalytic layer are provided in the reactor, the reactor forms a reaction chamber, the catalytic layer is installed in the reaction chamber, the spraying member is installed above the catalytic layer, and the spraying member is configured to spray ozone into the reaction chamber, high-purity water is introduced into the reaction chamber formed by the reactor, and the high-purity water and ozone generate active oxygen groups under the action of the catalyst, so that low-valent metal ions are oxidized into high-valent metal ions by the active oxygen groups.

5. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 2, characterized in that: The following steps are also included: The hydrofluoric acid waste liquid discharged from the cleaning tank is filtered through a filter before being introduced into the pretreatment component to remove solid impurities in the hydrofluoric acid waste liquid.

6. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 1, characterized in that: The following steps are also included: The distillate discharged from the bottom of the first distillation tower is introduced into a first transfer tank for storage. After the distillate in the first transfer tank reaches a predetermined amount, the distillate is guided from the first transfer tank to the second distillation tower.

7. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 1, characterized in that: The following steps are also included: The hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the second distillation tower is introduced into a second transfer tank for storage. The hydrofluoric acid can be guided to the pretreatment assembly from the second transfer tank.

8. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 1, characterized in that: The steps include: The first adsorber adsorbs water formed by condensation of water vapor discharged from the top of the light removal tower to remove metal ions in the water; The water treated by the first adsorber is introduced into a water storage tank for water recovery.

9. The hydrofluoric acid regeneration method for photovoltaic waste acid according to claim 1, characterized in that: The following steps are also included: The second adsorber adsorbs hydrofluoric acid formed by condensation of HF and water vapor discharged from the top of the first distillation tower to remove metal ions in the hydrofluoric acid; The hydrofluoric acid treated by the second adsorber is introduced into a product storage tank for hydrofluoric acid recovery.

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