Glass panel etching waste liquid treatment method

Abstract

The application discloses a glass panel etching waste liquid treatment method, which comprises the following steps: mixing an extraction organic phase with glass panel etching wastewater to extract a fluorine-containing organic phase and a raffinate water phase; the extraction agent of the extraction organic phase comprises diisooctyl phosphate, trialkyl phosphine oxide and tributyl phosphate; mixing the fluorine-containing organic phase with a potassium hydroxide solution to perform back extraction to obtain a back extraction liquid water phase; evaporating the back extraction liquid water phase to obtain potassium fluoride; adding aluminum hydroxide into the raffinate water phase, and mixing the two to perform an alkaline hydrolysis reaction to obtain a solid-liquid mixture; filtering the solid-liquid mixture to obtain aluminum fluoride, white carbon black and an alkaline hydrolysis filtrate. The glass panel etching waste liquid treatment method provided by the application realizes treatment of glass panel etching waste liquid, converts original components in the waste liquid into high-value chemical raw materials potassium fluoride, aluminum fluoride and white carbon black through chemical reactions, effectively recovers effective components of the glass panel etching waste liquid, and achieves the effect of changing waste into treasure and recycling resources.

Description

Technical Field

[0001] This invention relates to the field of etching waste liquid treatment technology, and more specifically, to a method for treating etching waste liquid from glass panels. Background Technology

[0002] The glass panel manufacturing industry generates a large amount of hydrofluoric acid etching wastewater during the glass panel production process. Currently, this etching wastewater is generally treated using lime chemical precipitation, which works by reacting lime with fluoride ions to form calcium fluoride precipitate, thus removing fluorides. However, this process produces a large amount of difficult-to-dispose mixed sludge, mainly composed of CaF2 and CaSO4. This type of sludge is classified as hazardous waste, resulting in high subsequent disposal costs. To reduce the fluoride ion concentration to emission standards, excessive lime needs to be added to the wastewater, leading to high reagent consumption and increased operating costs. The wastewater contains both free fluoride ions and complexed fluorosilicate ions. Traditional lime precipitation methods are insufficient to effectively destroy the fluorosilicate ions, causing the fluoride content in the treated wastewater to easily exceed the standard. Furthermore, valuable components in the wastewater cannot be recovered and utilized.

[0003] To address the aforementioned issues, the traditional process of treating glass panel etching waste liquid using lime chemical precipitation in the existing technology urgently needs improvement. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this invention provides a method for treating glass panel etching waste liquid, comprising the following steps: S10 Extraction Process: The organic phase to be extracted is mixed with glass panel etching wastewater at room temperature to carry out the extraction reaction, resulting in a fluorine-containing organic phase and a raffinate aqueous phase; wherein, the extractant in the organic phase includes the following components: diisooctyl phosphate and trialkylphosphine oxide tributyl phosphate. S20 back-extraction process: The fluorine-containing organic phase is mixed with a 15wt%-30wt% potassium hydroxide solution at room temperature to carry out a back-extraction reaction, resulting in an aqueous back-extraction solution and a regenerated organic phase; the aqueous back-extraction solution is evaporated to obtain potassium fluoride crystals; S30 Alkaline Hydrolysis Process: 6wt%-12wt% aluminum hydroxide is added to the raffinate aqueous phase. The raffinate aqueous phase and aluminum hydroxide are mixed at 70℃-90℃ to carry out an alkaline hydrolysis reaction to obtain a solid-liquid mixture. The solid-liquid mixture is filtered to obtain a solid mixture of aluminum fluoride and silica, as well as the alkaline hydrolysis filtrate.

[0005] Preferably, the volume ratio of diisooctyl phosphate, trialkylphosphine oxide, and tributyl phosphate in the extractant is (0.6-0.8):(0.3-0.5):0.5.

[0006] Preferably, the extractant content in the organic phase accounts for 50%-80% of the volume of the organic phase, and the diluent content accounts for 20%-50% of the volume of the organic phase.

[0007] Preferably, the diluent for extracting the organic phase includes one of the following components: kerosene or ethyl acetate.

[0008] Preferably, in step S10, the extracted organic phase and the glass panel etching wastewater are mixed and reacted at a volume ratio of 1:1 to 4:1 under stirring conditions of room temperature and 300 rpm to 500 rpm for 7 min to 15 min.

[0009] Preferably, in step S20, the fluorine-containing organic phase and a potassium hydroxide solution with a concentration of 15wt%-30wt% are mixed and reacted at a volume ratio of 2:1-4:1 under stirring conditions of room temperature and 500rpm-700rpm for 6min-10min.

[0010] Preferably, in step S30, the raffinate aqueous phase is heated, and aluminum hydroxide, accounting for 6wt%-12wt% of the mass fraction of the raffinate aqueous phase, is added, so that the raffinate aqueous phase and the aluminum hydroxide are mixed and reacted at a temperature of 70℃-90℃ for 20min-30min.

[0011] Preferably, the step S30 alkaline hydrolysis process further includes: S40. Recycle the alkaline hydrolysis filtrate to the extraction process; repeat the relevant operations of the extraction and back-extraction processes, or repeat the relevant operations of the extraction, back-extraction and alkaline hydrolysis processes, and circulate the filtrate until the concentration of fluoride ions in the raffinate or alkaline hydrolysis filtrate is lower than a preset threshold; the preset threshold is less than or equal to 4 g / L.

[0012] Preferably, after step S40, the method further includes: Excess calcium oxide or excess calcium chloride is added to the raffinate aqueous phase or alkaline filtrate to remove fluoride, resulting in a solid-liquid mixture containing calcium fluoride. The solid-liquid mixture is then filtered to obtain a fluoride-free filtrate.

[0013] Preferably, after step S30 or step S40, the method further includes: washing and drying the solid mixture, and using the different densities of aluminum fluoride and silica, separating the dried aluminum fluoride and silica in sequence through aging, sedimentation, and graded pressure filtration.

[0014] The beneficial effects of this invention are as follows: The glass panel etching wastewater treatment method provided by this invention involves mixing the extractable organic phase with the glass panel etching wastewater for an extraction reaction to obtain a fluorine-containing organic phase and a raffinate aqueous phase; mixing the fluorine-containing organic phase with a potassium hydroxide solution for a back-extraction reaction to obtain potassium fluoride crystals; adding aluminum hydroxide to the raffinate aqueous phase, and mixing the two at 70℃-90℃ for an alkaline hydrolysis reaction to obtain aluminum fluoride and silica. This method not only treats the glass panel etching wastewater but also utilizes a combination of extraction, back-extraction, and alkaline hydrolysis reactions to convert the fluorine and silicon sources in the wastewater into high-value-added chemical raw materials such as potassium fluoride, aluminum fluoride, and silica, effectively recovering the effective components of the glass panel etching wastewater and achieving the effect of turning waste into treasure and recycling resources. Attached Figure Description

[0015] The accompanying drawings, which are included to provide a further understanding of the invention and form part of this invention, illustrate exemplary embodiments of the invention and are used to explain the invention, but do not constitute an undue limitation of the invention. In the drawings: Figure 1 This is a schematic flowchart of the glass panel etching waste liquid treatment method of the present invention.

[0016] Figure 2 This is another schematic diagram of the glass panel etching waste liquid treatment method of the present invention. Detailed Implementation

[0017] The following drawings disclose several embodiments of the present invention. For clarity, many practical details will be described in the following description. However, it should be understood that these practical details are not intended to limit the invention. That is, in some embodiments of the invention, these practical details are not essential. Furthermore, for the sake of simplicity, some conventional structures and components will be shown in the drawings in a simple schematic manner.

[0018] It should be noted that all directional indications in the embodiments of the present invention, such as up, down, left, right, front, back, etc., are only used to explain the relative positional relationship and movement of the components in a specific posture as shown in the attached figure. If the specific posture changes, the directional indication will also change accordingly.

[0019] Furthermore, in this invention, the use of terms such as "first," "second," etc., is for descriptive purposes only and does not specifically refer to any order or sequence, nor is it intended to limit the invention. They are merely used to distinguish items or operations described using the same technical terms and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but only if they are feasible for those skilled in the art. If a combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0020] To further understand the invention's content, features, and effects, the following embodiments are provided, and detailed descriptions are given below in conjunction with the accompanying drawings: Reference Figure 1 , Figure 1 This is a schematic flowchart of the glass panel etching waste liquid treatment method of the present invention. The glass panel etching waste liquid treatment method provided by the present invention includes the following steps: S10 Extraction Process: The organic phase to be extracted is mixed with the glass panel etching wastewater at room temperature to carry out the extraction reaction, resulting in a fluorine-containing organic phase and a raffinate aqueous phase.

[0021] Specifically, in step S10, the extracted organic phase and the glass panel etching wastewater are mixed and reacted at a volume ratio of 1:1 to 4:1 under stirring conditions of room temperature and 300 rpm to 500 rpm for 7 min to 15 min.

[0022] In step S10, the organic phase used for extraction includes an extractant and a diluent. The extractant comprises the following components: diisooctyl phosphate, trialkylphosphine oxide, and tributyl phosphate. The volume ratio of these three components is (0.6-0.8):(0.3-0.5):0.5. The diluent comprises one of the following components: kerosene or ethyl acetate; that is, the diluent is either kerosene or ethyl acetate.

[0023] The extractant content in the organic phase accounts for 50%-80% of the volume of the organic phase, and the diluent content accounts for 20%-50% of the volume of the organic phase.

[0024] Fluorine exists in two forms in glass panel etching waste liquid: one is in the form of fluoride ions, and the other is in the form of fluorosilicate ions.

[0025] During the extraction process, free fluoride ions in the glass panel etching waste liquid react with the extractant and combine with it, allowing the free fluoride ions to enter the organic phase, resulting in a fluorine-containing organic phase and a raffinate aqueous phase.

[0026] S20 back-extraction process: The fluorine-containing organic phase is mixed with a 15wt%-30wt% potassium hydroxide solution at room temperature to carry out a back-extraction reaction, resulting in an aqueous back-extraction solution and a regenerated organic phase; the aqueous back-extraction solution is evaporated to obtain potassium fluoride crystals.

[0027] In step S20, the fluorine-containing organic phase and a potassium hydroxide solution with a concentration of 15wt%-30wt% are mixed and reacted at a volume ratio of 2:1-4:1 under stirring conditions of room temperature and 500rpm-700rpm for 6min-10min.

[0028] In this step, the fluorine-containing organic phase reacts with potassium hydroxide to generate an aqueous back-extraction solution containing potassium fluoroborate and potassium fluoride, and a regenerated organic phase. The aqueous back-extraction solution is filtered to obtain potassium fluoroborate precipitate and filtrate. The filtrate is evaporated to obtain potassium fluoride crystals. The regenerated organic phase is recycled back to the extraction process as the extraction organic phase for reuse.

[0029] S30 Alkaline Hydrolysis Process: 6wt%-12wt% aluminum hydroxide is added to the raffinate aqueous phase, and the two are mixed at 70℃-90℃ to carry out an alkaline hydrolysis reaction to obtain a solid-liquid mixture; the solid-liquid mixture is filtered to obtain a solid mixture of aluminum fluoride and silica, as well as an alkaline hydrolysis filtrate.

[0030] In step S30, the raffinate aqueous phase is heated, and aluminum hydroxide, accounting for 6wt%-12wt% of the mass fraction of the raffinate aqueous phase, is added, so that the two are mixed and reacted at a temperature of 70℃-90℃ for 20min-30min.

[0031] The raffinate aqueous phase contains fluorosilicate ions. In this step, the raffinate aqueous phase is heated to 70℃-90℃, and then aluminum hydroxide is added to the raffinate aqueous phase. The fluorosilicate ions react chemically with the aluminum hydroxide to produce aluminum fluoride and hydrated silica, that is, aluminum fluoride and silica, resulting in a solid-liquid mixture containing aluminum fluoride and silica. The solid-liquid mixture is then filtered to obtain a mixture of aluminum fluoride and silica, as well as an alkaline hydrolysis filtrate.

[0032] In the alkaline hydrolysis step, some of the fluorine in the fluorosilicate ions in the raffinate aqueous phase combines with aluminum to form aluminum fluoride, while the rest is converted into free fluoride ions. The silicon in the fluorosilicate ions is converted into hydrated silicon dioxide, i.e., into silica. Therefore, the alkaline hydrolysis filtrate contains free fluoride ions converted from fluorosilicate ions.

[0033] Further, see Figure 2 , Figure 2 This is another schematic flowchart of the glass panel etching waste liquid treatment method of the present invention. The glass panel etching waste liquid treatment method provided by the present invention further includes, after step S30 (alkaline hydrolysis), the following: S40. Recycle the alkaline hydrolysis filtrate back to the extraction process; repeat the extraction and back-extraction processes, or repeat the extraction, back-extraction, and alkaline hydrolysis processes, until the fluoride ion concentration in the raffinate or alkaline hydrolysis filtrate is lower than a preset threshold. The preset threshold is less than or equal to 4 g / L.

[0034] Because the alkaline hydrolysis filtrate contains free fluoride ions derived from the conversion of fluorosilicate ions, it needs to be recycled back to the extraction process to further remove these fluoride ions. After recycling back to the extraction process, the following methods can be used for the relevant operations: The first method involves repeatedly performing the extraction and back-extraction processes.

[0035] The second method involves repeatedly performing the extraction, back-extraction, and alkaline hydrolysis processes.

[0036] The specific method used depends on whether the fluoride ion concentration in the treated wastewater has fallen below a preset threshold. If, after repeated back-extraction, the fluoride ion concentration in the raffinate is below the preset threshold, no further alkaline hydrolysis is required. If the fluoride ion concentration in the raffinate does not meet the preset threshold, alkaline hydrolysis is necessary. If, after alkaline hydrolysis, the fluoride ion concentration in the corresponding filtrate falls below the preset threshold, the process ends. If the fluoride ion concentration in the corresponding filtrate still does not meet the preset threshold, the filtrate must be recycled back to the extraction process for extraction and subsequent steps until the fluoride ion concentration in the treated wastewater falls below the preset threshold.

[0037] Furthermore, after step S40, the method further includes: adding excess calcium oxide or excess calcium chloride to the raffinate aqueous phase or alkaline filtrate to remove fluoride from the raffinate aqueous phase or alkaline filtrate, obtaining a solid-liquid mixture containing calcium fluoride, and filtering the solid-liquid mixture to obtain a fluoride-free filtrate.

[0038] When the concentration of fluoride ions in the aqueous raffinate or alkaline filtrate is lower than a preset threshold, excess calcium oxide or calcium chloride can be added to the aqueous raffinate or alkaline filtrate to react with the fluoride ions in the aqueous raffinate or alkaline filtrate to form calcium fluoride precipitate, thereby removing the fluoride ions from the aqueous raffinate or alkaline filtrate and obtaining fluoride-free filtrate. After further harmless treatment of the fluoride-free filtrate, it can be discharged.

[0039] Furthermore, after step S30 or step S40, the following process is also included: washing and drying the solid mixture, and separating the dried aluminum fluoride and silica by aging-sedimentation-grading pressure filtration separation method, taking advantage of the different densities of aluminum fluoride and silica.

[0040] The glass panel etching wastewater treatment method provided by this invention involves mixing the extractable organic phase with the glass panel etching wastewater for an extraction reaction to obtain a fluorine-containing organic phase and a raffinate aqueous phase; mixing the fluorine-containing organic phase with a potassium hydroxide solution for a back-extraction reaction to obtain potassium fluoride crystals; adding aluminum hydroxide to the raffinate aqueous phase, and mixing the two at 70℃-90℃ for an alkaline hydrolysis reaction to obtain aluminum fluoride and silica. This method not only treats the glass panel etching wastewater but also utilizes chemical reactions to convert the original components in the wastewater into chemical raw materials such as potassium fluoride, aluminum fluoride, and silica, effectively recovering the effective components of the glass panel etching wastewater and achieving the effect of turning waste into treasure and recycling resources.

[0041] The technical solution of the present invention will be further described in detail below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and do not constitute a limitation on the scope of protection of the present invention. Equivalent adjustments or optimizations made by those skilled in the art based on the core concept of the present invention should still fall within the scope of protection of the present invention.

[0042] Example 1 The glass panel etching waste liquid provided in this embodiment is 1000 liters with a total fluoride content (C1) of 190 g / L, a free fluoride content (C2) of 38 g / L, and an acidity (P1) of 12 mol / L. The target is to stop the extraction-back-extraction-alkaline hydrolysis process when the fluoride content in the raffinate or alkaline hydrolysis filtrate is below 3 g / L. It is then discharged after further treatment.

[0043] This embodiment specifically includes the following glass panel etching waste liquid treatment process: Step S10 Extraction Process (First Extraction): The extracted organic phase and glass panel etching waste liquid were mixed and reacted at a volume ratio of 2:1 (R1) under the conditions of T1 of 25℃ and stirring rate N1 of 400 rpm for t1 of 10 min to obtain a fluorine-containing organic phase and a raffinate aqueous phase; the fluorine-containing organic phase and the raffinate aqueous phase were then separated.

[0044] The organic phase for extraction includes an extractant and a diluent. The extractant consists of dioctyl phosphate, trialkylphosphine oxide, and tributyl phosphate in a volume ratio of 0.6:0.3:0.5. The diluent is ethyl acetate. The extractant and diluent each comprise 50% of the volume of the organic phase for extraction.

[0045] Step S20 Back-extraction process (first back-extraction): A fluorine-containing organic phase and a 30 wt% KOH solution (w1) were mixed at a volume ratio of 3:1 (R2) and subjected to a back-extraction reaction at a temperature (T2) of 25°C and a stirring speed (N2) of 600 rpm for 7 min, yielding an aqueous back-extraction solution and a regenerated organic phase. The aqueous back-extraction solution and the regenerated organic phase were then separated.

[0046] The aqueous phase of the back-extraction solution was filtered, and the filtered filtrate was evaporated using a multi-effect evaporator. The vacuum degree of the multi-effect evaporator was set to -0.06 MPa, and evaporation was carried out sequentially at 90℃ for 3 min, at 70℃ for 4 min, and at 50℃ for 6 min. After cooling, potassium fluoride crystals with a purity of 98% and a mass M1 of 116.2 kg were obtained.

[0047] Step S30 Alkali hydrolysis (first alkali hydrolysis): The raffinate aqueous phase is heated to T3 (85°C). Aluminum hydroxide (9 wt% W1) is added to the raffinate aqueous phase, and the reaction is carried out at a stirring speed N3 (1000 rpm) for t3 (25 min) to obtain a solid-liquid mixture containing aluminum fluoride and silica. The solid-liquid mixture is filtered to obtain a mixture of aluminum fluoride and silica and an alkali hydrolysis filtrate. The mixture of aluminum fluoride and silica is washed and dried to obtain a solid mixture of aluminum fluoride and silica. The solid mixture of aluminum fluoride and silica is separated by an aging-sedimentation-grading pressure filtration method. The mass of aluminum fluoride is M2 (87.87 kg) and the mass of silica is M3 (45.6 kg).

[0048] Step S40: Recycle the alkaline hydrolysis filtrate back to the extraction process, and repeat the extraction process, back-extraction process and alkaline hydrolysis process.

[0049] Specifically, it includes: Step S41: Recycle the alkaline hydrolysis filtrate to the extraction process (second extraction) and the back-extraction process (second back-extraction), repeat the above step S10 to obtain the first fluorine-containing organic phase and the first raffinate aqueous phase; repeat the above step S20 to obtain potassium fluoride crystals with a mass M4 of 86.58 kg and the regenerated organic phase.

[0050] Step S42: The first raffinate aqueous phase is recycled back to the alkaline hydrolysis process (second alkaline hydrolysis). The first raffinate aqueous phase is heated to 80°C, and aluminum hydroxide with a mass fraction (W2) of 6 wt% is added to the first raffinate aqueous phase. The two are reacted at a stirring speed (N4) of 1000 rpm for t4 of 25 min to obtain a first solid-liquid mixture containing aluminum fluoride and silica. The first solid-liquid mixture is filtered to obtain a first mixture of aluminum fluoride and silica and a first alkaline hydrolysis filtrate. The first mixture of aluminum fluoride and silica is washed and dried to obtain a solid mixture of aluminum fluoride and silica. The solid mixture of aluminum fluoride and silica is separated by an aging-sedimentation-fractional pressure filtration method to obtain aluminum fluoride with a mass of M5 of 59.91 kg and silica with a mass of M6 of 31.3 kg.

[0051] Step S43: The first alkaline hydrolysis filtrate is recycled to the extraction process (third extraction) and the back-extraction process (third back-extraction). Steps S10 and S20 are repeated to obtain 61.72 kg of potassium fluoride crystals (M7) and a second raffinate aqueous phase with a fluorine content of 2.41 g / L.

[0052] Step S50: Add excess calcium oxide or excess calcium chloride to the second raffinate aqueous phase to remove fluoride from the second extraction aqueous phase, obtaining a solid-liquid mixture containing calcium fluoride. Filter the solid-liquid mixture to obtain a fluoride-free solution. The fluoride-free solution is discharged after other necessary safety treatments.

[0053] In this embodiment, since the fluoride content in the second raffinate aqueous phase is 2.41 g / L, which is lower than the preset threshold of 3 g / L, there is no need to perform alkaline hydrolysis on the second raffinate aqueous phase.

[0054] The method for separating the solid mixture of aluminum fluoride and hydrated silica (white carbon black) using the aging-sedimentation-grading pressure filtration separation method specifically includes: 1. Pulping Section The dried aluminum fluoride and hydrated silica mixture is added to deionized water or recycled process water at a solid-liquid ratio of 1:3 to 1:6 (mass ratio), and stirred and dispersed in a mixing tank at room temperature for 30 to 60 minutes to prepare a uniform suspension slurry.

[0055] Note: Hydrated silica is easily dispersed in water to form a suspended colloid, while aluminum fluoride particles have a high density and strong hydrophobicity. The sedimentation behavior of the two in the slurry is significantly different, which provides conditions for subsequent separation.

[0056] 2. Chenhua Chemical Section The above slurry is transferred to an aging tank and aged at a constant temperature of 60-90℃ for 2-6 hours with a stirring speed of 30-60 r / min.

[0057] Aging effect: After the aluminum fluoride microparticles dissolve, they recrystallize on the surface of the larger particles, which increases the particle size of the aluminum fluoride. Hydrated silica flocs further aggregate and grow, improving sedimentation performance.

[0058] 3. Settlement Separation Section After aging, the slurry is transferred to a settling tank (conical bottom structure) while still hot and allowed to settle at 50-80℃ for 4-12 hours.

[0059] Stratification results: Bottom layer: Aluminum fluoride precipitate (white, dense layer) Upper layer: Hydrated silica suspension (milky white flocculent suspension) Middle layer: Clear liquid (can be reused for pulping) Separation operation: First, collect the upper layer of hydrated silica suspension through the overflow port; Then, the bottom layer of aluminum fluoride slurry is discharged through the bottom outlet.

[0060] 4. Aluminum fluoride recycling The bottom AlF3 slurry is fed into a plate and frame filter press and filtered for 30 to 60 minutes under a pressure of 0.4 to 0.6 MPa to obtain aluminum fluoride filter cake, which is then dried at 105 to 120°C to constant weight.

[0061] 5. Recycling of hydrated silica The upper suspension is fed into a precision plate and frame filter press (filter cloth precision 0.5–1.0 μm) and filtered at 0.3–0.5 MPa for 60–120 minutes. The filter cake is then slurried with deionized water at a mass ratio of 1:2–1:5, filtered again, and washed 2–3 times to remove entrained soluble impurities. After washing, the filter cake is dried at 105–120℃ to constant weight to obtain hydrated silica (white carbon black).

[0062] The total fluoride content in the glass panel etching waste liquid provided in Example 1 was detected using the alkali fusion-fluoride ion selective electrode method, and the specific testing procedure was performed in accordance with HG / T 6267-2024 "Determination of Fluoride Content in Copper-Containing Etching Waste Liquid". The free fluoride content in the waste liquid was detected using the direct fluoride ion selective electrode method, specifically referring to GB / T 7484-1987 "Determination of Fluorides in Water - Ion Selective Electrode Method". The total acidity in the waste liquid was detected using the acid-base titration method, specifically referring to HG / T 5018-2016 "Analysis Method for Main Components and Trace Metal Elements in Copper-Containing Etching Waste Liquid". Specific test results are shown in Table 1, which contains the process parameter values ​​corresponding to Examples 1 to 3 of this invention.

[0063] The potassium fluoride, aluminum fluoride, and silica generated during the treatment of glass panel etching waste liquid in Example 1 were subjected to phase identification, mass determination, and purity verification. The mass determination results are shown in Table 1. The specific details of the phase identification, mass determination, and purity verification are as follows: 1. Potassium fluoride: 1.1 Phase Identification: The product was analyzed using X-ray diffraction (XRD). Test conditions: Cu target, Kα rays, scanning range 2θ = 10°~80°. The obtained spectrum was compared with the potassium fluoride standard PDF card (No. 00-001-0982). The characteristic diffraction peaks were consistent, confirming that the product was potassium fluoride.

[0064] 1.2. Mass determination: The separated potassium fluoride product was dried at 105±5℃ to constant weight, weighed using an analytical balance, and the mass was recorded.

[0065] 1.3 Purity verification: The fluoride content was determined by the fluoride ion selective electrode method.

[0066] 2. Aluminum fluoride (AlF3) 2.1 Phase Identification: The product was analyzed using X-ray diffraction (XRD). Test conditions: Cu target, Kα rays, scanning range 2θ = 10°~80°. The obtained spectrum was compared with the standard PDF card of aluminum fluoride (No. 00-044-0232). The characteristic diffraction peaks were consistent, confirming that the product was aluminum fluoride.

[0067] 2.2 Mass determination: The separated aluminum fluoride product was dried at 105±5℃ to constant weight, weighed using an analytical balance, and the mass was recorded.

[0068] 2.3 Purity verification: The fluorine content was determined by the alkali fusion-fluoride ion selective electrode method.

[0069] 3. Hydrated silica (SiO2·nH2O, white carbon black) 3.1 Phase Identification: The product was analyzed using X-ray diffraction (XRD). Test conditions: Cu target, Kα rays, scanning range 2θ = 10°~80°. Hydrated silica is an amorphous material; its XRD pattern shows a broad and diffuse scattering peak in the range 2θ = 20°~25°, without sharp crystalline diffraction peaks. Based on this, the product was confirmed to be hydrated silica.

[0070] 3.2 Mass determination: The separated hydrated silica product was dried at 105±5℃ to constant weight, weighed using an analytical balance, and the mass was recorded.

[0071] 3.3 Component verification: The loss on ignition method was used.

[0072] Table 1:

[0073] Example 2 The process flow and operation steps of the glass panel etching waste liquid treatment method provided in Example 2 are the same as those in Example 1, except that the process parameter values ​​for each step are adjusted according to the values ​​shown in Table 1 below. Meanwhile, the detection methods for total fluoride content, free fluoride content, and total acidity in the glass panel etching waste liquid provided in Example 2 are the same as those in Example 1. Furthermore, the phase identification, quality determination, and purity verification methods for potassium fluoride, aluminum fluoride, and silica generated during the treatment of glass panel etching waste liquid in Example 2 are the same as those in Example 1.

[0074] Example 3 The process flow and operation steps of the glass panel etching waste liquid treatment method provided in Example 3 are the same as those in Example 1, except that the process parameter values ​​for each step are adjusted according to the values ​​shown in Table 1 below. Meanwhile, the detection methods for total fluoride content, free fluoride content, and total acidity in the glass panel etching waste liquid provided in Example 3 are the same as those in Example 1. Furthermore, the phase identification, quality determination, and purity verification methods for potassium fluoride, aluminum fluoride, and silica generated during the treatment of the glass panel etching waste liquid in Example 3 are the same as those in Example 1.

[0075] Example 4 The process flow and operation steps of the glass panel etching waste liquid treatment method provided in Example 4 are the same as those in Example 1, except that the process parameter values ​​for each step are adjusted according to the values ​​shown in Table 1 below. The extractant is composed of dioctyl phosphate, trialkylphosphine oxide, and tributyl phosphate in a volume ratio of 0.8:0.5:0.5; the diluent is kerosene. The extractant accounts for 80% of the volume of the extracted organic phase, and the diluent accounts for 20%. The detection methods for total fluoride content, free fluoride content, and total acidity in the glass panel etching waste liquid provided in Example 4 are the same as those in Example 1. Furthermore, the phase identification, quality determination, and purity verification methods for potassium fluoride, aluminum fluoride, and silica generated during the treatment of the glass panel etching waste liquid in Example 4 are the same as those in Example 1.

[0076] Example 5 The process flow and operation steps of the glass panel etching waste liquid treatment method provided in Example 5 are the same as those in Example 1, except that the process parameter values ​​for each step are adjusted according to the values ​​shown in Table 1 below. The extractant is composed of dioctyl phosphate, trialkylphosphine oxide, and tributyl phosphate in a volume ratio of 0.7:0.4:0.5; the diluent is ethyl acetate. The extractant accounts for 70% of the volume of the extracted organic phase, and the diluent accounts for 30%. The detection methods for total fluoride content, free fluoride content, and total acidity in the glass panel etching waste liquid provided in Example 5 are the same as those in Example 1. Furthermore, the phase identification, quality determination, and purity verification methods for potassium fluoride, aluminum fluoride, and silica generated during the treatment of the glass panel etching waste liquid in Example 5 are the same as those in Example 1.

[0077] The glass panel etching waste liquid treatment method provided by this invention, as shown in Table 1 (Examples 1 to 5), yields potassium fluoride, aluminum fluoride, and silica, and the fluoride ion concentration in the treated waste liquid. This invention utilizes an extraction-back-extraction-alkaline hydrolysis-re-extraction-back-extraction (alkaline hydrolysis) process to treat the etching waste liquid. This allows the fluoride and silicon sources in the etching waste liquid to combine with the potassium and aluminum sources to produce three high-value-added products: potassium fluoride, aluminum fluoride, and hydrated silica (silica). This achieves the recovery and high-value utilization of the fluoride and silicon sources in the etching waste liquid, avoiding the generation of fluoride-containing sludge.

[0078] The raffinate phase described in step S40 of this invention includes the raffinate phase, the first raffinate phase, and the second raffinate phase described in other paragraphs of this invention. The alkaline hydrolysis filtrate described in step S40 includes the alkaline hydrolysis filtrate and the first alkaline hydrolysis filtrate described in other paragraphs of this invention.

[0079] The normal temperature mentioned in this invention refers to the temperature between 20°C and 40°C.

[0080] The above description is merely an embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of the present invention should be included within the scope of the claims of the present invention.

Claims

1. A method for treating glass panel etching waste liquid, characterized in that, Includes the following steps: S10 Extraction Process: The organic phase to be extracted is mixed with glass panel etching wastewater at room temperature to carry out the extraction reaction, resulting in a fluorine-containing organic phase and a raffinate aqueous phase; wherein, the extractant in the organic phase includes the following components: diisooctyl phosphate, trialkylphosphine oxide, and tributyl phosphate. S20 Back-extraction process: The fluorine-containing organic phase is mixed with a 15wt%-30wt% potassium hydroxide solution at room temperature to carry out a back-extraction reaction, resulting in an aqueous back-extraction solution and a regenerated organic phase; the aqueous back-extraction solution is evaporated to obtain potassium fluoride crystals; S30 Alkali hydrolysis process: 6wt%-12wt% aluminum hydroxide is added to the raffinate aqueous phase, and the raffinate aqueous phase and the aluminum hydroxide are mixed at 70℃-90℃ to carry out an alkali hydrolysis reaction to obtain a solid-liquid mixture; the solid-liquid mixture is filtered to obtain a solid mixture of aluminum fluoride and silica and an alkali hydrolysis filtrate.

2. The method for treating glass panel etching waste liquid according to claim 1, characterized in that, The volume ratio of diisooctyl phosphate, trialkylphosphine oxide, and tributyl phosphate in the extractant is (0.6-0.8):(0.3-0.5):0.

5.

3. The method for treating glass panel etching waste liquid according to claim 1, characterized in that, The extractant content in the extracted organic phase accounts for 50%-80% of the volume of the extracted organic phase, and the diluent content accounts for 20%-50% of the volume of the extracted organic phase.

4. The method for treating glass panel etching waste liquid according to any one of claims 1 to 3, characterized in that, The diluent for extracting the organic phase includes one of the following components: kerosene or ethyl acetate.

5. The method for treating glass panel etching waste liquid according to claim 1, characterized in that, In step S10, the extracted organic phase and the glass panel etching wastewater are mixed and reacted at a volume ratio of 1:1 to 4:1 under stirring conditions of room temperature and 300 rpm to 500 rpm for 7 min to 15 min.

6. The method for treating glass panel etching waste liquid according to claim 1, characterized in that, In step S20, the fluorine-containing organic phase and a potassium hydroxide solution with a concentration of 15wt%-30wt% are mixed and reacted at a volume ratio of 2:1-4:1 under stirring conditions of room temperature and 500rpm-700rpm for 6min-10min.

7. The method for treating glass panel etching waste liquid according to claim 1, characterized in that, In step S30, the alkali hydrolysis process, the raffinate aqueous phase is heated, and aluminum hydroxide, accounting for 6wt%-12wt% of the mass fraction of the raffinate aqueous phase, is added to mix and react the raffinate aqueous phase and the aluminum hydroxide at a temperature of 70℃-90℃ for 20min-30min.

8. The method for treating glass panel etching waste liquid according to claim 1, characterized in that, Following step S30, the alkaline hydrolysis process, the following is also included: S40. Recycle the alkaline hydrolysis filtrate to the extraction process; repeat the extraction and back-extraction processes, or repeat the extraction, back-extraction, and alkaline hydrolysis processes, until the fluoride ion concentration in the raffinate aqueous phase or alkaline hydrolysis filtrate is lower than a preset threshold; the preset threshold value is less than or equal to 4 g / L.

9. The method for treating glass panel etching waste liquid according to claim 8, characterized in that, The process following step S40 also includes: Excess calcium oxide or excess calcium chloride is added to the raffinate aqueous phase or alkaline filtrate to remove fluoride, resulting in a solid-liquid mixture containing calcium fluoride. The solid-liquid mixture is then filtered to obtain a fluoride-free filtrate.

10. The method for treating glass panel etching waste liquid according to claim 8, characterized in that, The step S30 or step S40 further includes: washing and drying the solid mixture, and using the different densities of aluminum fluoride and silica, separating the dried aluminum fluoride and silica in sequence through aging, sedimentation, and graded pressure filtration.

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