Method and equipment for purifying electronic-grade high-purity 1-hydroxyethylidene-1, 1-diphosphonic acid

Abstract

The invention relates to the technical field of production of electronic-grade chemical products, and provides a purification method of electronic-grade high-purity 1-hydroxyethylidene-1, 1-diphosphonic acid. The method provided by the invention comprises the following steps: a dissolving step: uniformly dissolving an industrial-grade hydroxyethylidene-1, 1-diphosphonic acid raw material; a filtering step: removing large particles from the industrial-grade hydroxyethylidene-1, 1-diphosphonic acid solution through a micro-filter, removing zwitterions through a zwitterion removal device, and removing micro particles through a nano-filter in sequence; a crystallization step: carrying out crystallization treatment on the HEDP solution from which the microparticles are removed to obtain an electronic-grade high-purity HEDP crystal; and a drying step: drying the electronic-grade high-purity hydroxyethylidene-1, 1-diphosphonic acid crystal. The method can meet the standard requirements of the industries of general semiconductors, aerospace, photoelectricity and the like, and realizes the production of electronic-grade HEDP from industrial-grade HEDP.

Description

Technical Field

[0001] The invention belongs to the technical field of wet electronic chemicals, and in particular relates to a method and equipment for purifying electronic-grade high-purity hydroxyethylidene diphosphonic acid. Background Art

[0002] Hydroxyethylidene diphosphonic acid (HEDP) can be used in photoresists required by the pan-semiconductor industry to stabilize the quality of the developer, enhance the fixing effect, shorten the development time, avoid precipitation, and have strong antioxidant properties, solubility, and permeability. It is an important additive in photoresists. As the semiconductor industry has increasingly intensive requirements for integrated circuit line widths, the requirements for the cleanliness of wet electronic chemicals have become increasingly higher, and the requirements for harmful metal ion content have increased from 10 -6 Raised to 10 -9 , which places higher requirements on processing equipment, materials, containers and environment and significantly increases costs. However, hydroxyethylidene diphosphoric acid has a strong ability to chelate metal ions, and how to remove the metal ions in it is a difficult problem in the industry. There is no literature at home and abroad that publicly reports how to use industrial-grade hydroxyethylidene diphosphoric acid as a raw material to purify high-purity electronic-grade hydroxyethylidene diphosphoric acid required by the pan-semiconductor industry, aerospace and optoelectronic fields.

[0003] Patent CN 117361566 A discloses a method for preparing a high-purity ammonium fluoride aqueous solution, which specifically comprises: dissolving industrial ammonium fluoride in an organic solvent, recrystallizing, drying, and then dissolving in high-purity water, passing through a cation exchange resin and an anion exchange resin in sequence to remove metal salt impurities, and then filtering with a three-stage microporous membrane to obtain a high-purity ammonium fluoride aqueous solution. However, the method of removing most impurities by recrystallization with an organic solvent and then deep impurity removal with a cation exchange resin and an anion exchange resin is not effective in removing iron ions and calcium ions from hydroxyethylidene diphosphoric acid, and hydroxyethylidene diphosphoric acid that meets the electronic grade chemical standard cannot be obtained. Summary of the invention

[0004] In view of the above technical problems, the present invention proposes that the cation exchange resin is prepared by swelling a skeleton composed of a copolymer of styrene and vinylbenzene in a volume ratio of 5:1, acidifying with sulfuric acid and sulfate, and then washing to a pH value of 5-6.

[0005] The present invention also provides an anion exchange resin, wherein the anion exchange resin is prepared by sequentially subjecting a skeleton composed of a copolymer of styrene and vinylbenzene in a volume ratio of 5:1 to chloromethylation and amination.

[0006] The present invention also provides an anion and cation removal device, which comprises the above-mentioned cation exchange resin and the above-mentioned anion exchange resin.

[0007] On the other hand, the present invention provides a method for purifying electronic-grade high-purity hydroxyethylidene diphosphoric acid, which can meet the standard requirements of the semiconductor, aerospace, optoelectronics and other industries, and realize the production of electronic-grade hydroxyethylidene diphosphoric acid from industrial-grade hydroxyethylidene diphosphoric acid.

[0008] The method proposed by the present invention comprises the following steps:

[0009] Dissolving step: dissolving the industrial grade hydroxyethylidene diphosphonic acid raw material uniformly;

[0010] Filtration step: the industrial-grade hydroxyethylidene diphosphonic acid solution is sequentially passed through a microfilter to remove large particles, passed through the above-mentioned anion and cation removal device to remove anions and cations, and passed through a nanofilter to remove microparticles;

[0011] Crystallization step: subjecting the hydroxyethylidene diphosphonic acid solution after removing the microparticles to crystallization treatment to obtain electronic grade high-purity hydroxyethylidene diphosphonic acid crystals;

[0012] Drying step: drying the electronic grade high-purity hydroxyethylidene diphosphonic acid crystals;

[0013] In the industrial-grade hydroxyethylidene diphosphoric acid raw material, the purity of hydroxyethylidene diphosphoric acid is above 97% by mass, the mass content of phosphoric acid is below 0.5%, the mass content of phosphorous acid is below 0.8%, the mass content of chloride is below 100ppm, and the mass content of iron is below 10ppm.

[0014] As an improvement, the dissolving step specifically includes introducing industrial-grade hydroxyethylidene diphosphonic acid, a solvent and a chelating agent into a stirring and heating mixer to dissolve into a hydroxyethylidene diphosphonic acid solution; the temperature of the stirring and heating mixer does not exceed 80°C.

[0015] As an improvement, the solvent in the dissolving step includes but is not limited to water, methanol, ethanol, n-propanol, isopropanol, acetone, methyl acetate, ethyl acetate, etc., or a mixture of several of them; the chelating agent in the dissolving step includes but is not limited to tetrasodium ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid, sodium tripolyphosphate, tetrasodium iminodisuccinate, trisodium nitrilotriacetic acid, ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, polyaspartic acid, and citric acid, or a mixture of several of them.

[0016] As an improvement, the nanofilter includes but is not limited to one or more of polytetrafluoroethylene membrane, polyethersulfone membrane, polyvinylidene fluoride membrane, polyimide membrane, and polyamide membrane in series, and the pore size of the filter membrane of the nanofilter is 10-50nm.

[0017] As an improvement, the crystallization step adopts one or a combination of a suspended stirring crystallizer, a plate crystallizer and a falling film crystallizer, and the crystallization temperature does not exceed 80°C.

[0018] As an improvement, the drying step is specifically vacuum drying, and the drying temperature does not exceed 80°C.

[0019] The cation exchange resin of the anion and cation removal device includes one or more resins with polystyrene-divinylbenzene as the skeleton and grafted with sulfonic acid groups, carboxyl groups or quaternary amine groups. The anion exchange resin includes any one or more resins with polystyrene-polysulfone as the skeleton and grafted with sulfonic acid groups. The anion exchange resin or cation exchange resin uses a functional resin with a particle size of less than 1 mm and a uniformity coefficient of less than 1.25.

[0020] The process of the invention is simple, and the hydroxyethylidene diphosphoric acid content of the electronic-grade hydroxyethylidene diphosphoric acid product is obtained by using cheap industrial-grade hydroxyethylidene diphosphoric acid as a raw material. The hydroxyethylidene diphosphoric acid content of the electronic-grade hydroxyethylidene diphosphoric acid product is more than 99%, and the single metal ion content is less than 10 ppb, which can meet the standard requirements of the pan-semiconductor, aerospace, optoelectronics and other industries. The electronic-grade hydroxyethylidene diphosphoric acid is produced from the industrial-grade hydroxyethylidene diphosphoric acid. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 :Flowchart of a solution;

[0022] Figure 2 : Device connection relationship of a solution. DETAILED DESCRIPTION

[0023] The following examples further illustrate the content of the present invention, but should not be construed as limiting the present invention. Without departing from the spirit and substance of the present invention, modifications or substitutions made to the methods, steps or conditions of the present invention all fall within the scope of the present invention.

[0024] Example 1 Cationic exchange resin synthesis method example

[0025] S1 Preparation of ion exchange resin skeleton (suspension copolymerization of styrene and divinylbenzene): add 120 liters of deionized water and 5 liters of dispersant (the dispersant can be: polyvinyl alcohol (PVA), starch, gelatin, this patent uses 10% polyvinyl alcohol aqueous solution) to a polytetrafluoroethylene container, add 20 liters of styrene, 4 liters of divinylbenzene and 300 grams of initiator (benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide can be used, we use benzoyl peroxide (BPO) as the initiator) to the polytetrafluoroethylene container, shake until the initiator is dissolved and pour into the polytetrafluoroethylene container, start stirring and control a certain stirring speed to disperse the monomer into beads of a certain size, and react at about 80°C for 2 hours. Wash, filter, vacuum dry and set aside.

[0026] S2 Ion exchange resin skeleton functionalization: Place about 5 kg of weighed dry ion exchange resin skeleton in a polytetrafluoroethylene container, add 30 liters of swelling agent (ethylene dichloride), swell at 60°C for half an hour, then heat to 70°C, then add 250 grams of silver sulfate and 30 liters of 98% concentrated sulfuric acid in sequence, and complete the addition within 15 minutes. Then heat to 80°C and react for 2-3 hours. Cool to room temperature, slowly add 50 liters of 25-30% dilute sulfuric acid to the polytetrafluoroethylene container, and after the system temperature drops to room temperature, add 200 liters of distilled water, stir for a few minutes, and filter; add 200 liters of distilled water for washing, stir for 10 minutes, and measure the pH value; if the pH value is less than 5, continue the washing-drying process until the solution pH value is greater than 5. The resulting product is finally dried to obtain a cation exchange resin.

[0027] Example 2 Anion Exchange Resin Synthesis Method Example

[0028] S1 Preparation of ion exchange resin skeleton (suspension copolymerization of styrene and divinylbenzene): Styrene and divinylbenzene monomers are suspended and copolymerized in water phase under the initiation of benzoyl peroxide. This step specifically includes the following steps:

[0029] S11 water phase preparation: pure water, dispersant (starch or gelatin can be used, we use 15% gelatin aqueous solution as dispersant), and methylene blue are put into a polymerization kettle, stirred and heated to 47°C for use;

[0030] S12 oil phase preparation: put styrene, divinylbenzene, initiator (benzoyl peroxide, lauroyl peroxide, di-tert-butyl peroxide are all OK, we use benzoyl peroxide as initiator) into the mixing kettle at room temperature, and put into the water phase polymerization kettle after mixing. After the oil phase is put into the polymerization kettle, the temperature is raised in stages under stirring for suspension polymerization, and solidification begins after reaching 95°C. Keep warm for 6 hours to obtain the polymerized bead reactant - ion exchange resin skeleton material. Draw off the mother liquor, put the ion exchange resin skeleton material into the filter and wash it with 90°C hot pure water for 3-4 times until the waste water is discharged. The washed skeleton material is dried (80-95°C), and the finished ion exchange resin skeleton material can be obtained after screening after drying in a fluidized bed.

[0031] S2 Ion Exchange Resin Skeleton Functionalization: The anion exchange resin functionalization of this patent is achieved by two steps of chloromethylation and amination. The specific process is as follows:

[0032] S21 ion exchange resin skeleton material is treated with a catalyst (the catalyst can be zinc chloride or ferric oxide), and chloromethyl ether is added to the material, and the temperature is maintained at 20-25°C for 2 hours, and then the temperature is raised to 45-48°C and the reaction is carried out for 12 hours to obtain a chlorinated skeleton material;

[0033] After adding methylal to the S22 chlorinated skeleton material and washing it three times, add methylal again, keep it at 20-25℃ (not exceeding 25℃), keep it for 4 hours, then raise the temperature to 30-35℃ (not exceeding 35℃) and add 20-35% by weight (dimethylammonium or trimethylammonium), react for 10 hours, then raise the temperature to 38-40℃ (not exceeding 42℃), react for 6 hours, reduce to room temperature, wash with methanol 3 times, add 1 mole / L hydrochloric acid, keep it for 1 hour, wash with ultrapure water until neutral, and obtain anion exchange resin.

[0034] The chelating agent used in the following examples is from Sinopharm Group, and hydroxyethylidene diphosphonic acid is from Shandong Taihe Water Treatment Technology Co., Ltd. The resin used in this patent is a functional resin customized and developed by Beijing Ximing Technology Co., Ltd., and the raw material resin is from Lanxiao Technology, Purolite (China) Co., Ltd. and DuPont.

[0035] The feed treated in the following examples is an industrial-grade hydroxyethylidene diphosphoric acid raw material (powder), wherein the hydroxyethylidene diphosphoric acid purity is above 97% by mass, the phosphoric acid mass content is below 0.5% (as PO43-), the phosphorous acid mass content is below 0.8% (as PO33-), the chloride (as Cl-) mass content is below 100 ppm, the calcium mass content is below 200 ppm, the sodium mass content is below 200 ppm, and the iron mass content is below 10 ppm. The specific indicators of the contents of other metal cation impurities in the industrial-grade hydroxyethylidene diphosphoric acid raw material are shown in Table 1 below.

[0036] Table 1. Impurity content in industrial grade hydroxyethylidene diphosphonic acid raw materials

[0037]

[0038] Example 3: Method for Purifying Electronic Grade High-Purity Hydroxyethylidene Diphosphonic Acid

[0039] This embodiment includes Figure 1 The following steps are shown:

[0040] S1 dissolving step: dissolving the industrial grade hydroxyethylidene diphosphonic acid raw material uniformly;

[0041] S2 filtration step: the industrial-grade hydroxyethylidene diphosphonic acid solution is sequentially passed through a microfilter to remove large particles, through an anion and cation removal device to remove anions and cations, and through a nanofilter to remove microparticles;

[0042] S3 crystallization step: the hydroxyethylidene diphosphonic acid solution after the microparticles are removed is subjected to crystallization treatment to obtain electronic grade high-purity hydroxyethylidene diphosphonic acid crystals;

[0043] S4 drying step: drying the electronic grade high-purity hydroxyethylidene diphosphonic acid crystals.

[0044] The S1 specifically comprises: industrial-grade hydroxyethylidene diphosphonic acid and solvent in a mass ratio of 1:1-2, and chelating agent (tetrasodium ethylenediaminetetraacetic acid) in solvent 2 with a mass content of 10-20ppm entering a stirring and heating mixer to dissolve into a hydroxyethylidene diphosphonic acid solution; the temperature of the stirring and heating mixer does not exceed 80°C. The chelating agent in other embodiments is not limited to tetrasodium ethylenediaminetetraacetic acid, but also includes ethylenediaminetetraacetic acid, sodium tripolyphosphate, tetrasodium iminodisuccinate, trisodium nitrilotriacetic acid, ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, polyaspartic acid, citric acid, one or more of which are mixed.

[0045] The solvent of S1 is water, but other embodiments are not limited to water, and also include: methanol, ethanol, n-propanol, isopropanol, acetone, methyl acetate, ethyl acetate and other one or more mixed solvents. The product obtained after the drying step has a purity mass content of more than 99% and a single metal ion content of less than 10 ppb, which can meet the standard requirements of the semiconductor, aerospace, optoelectronics and other industries. The production of electronic grade hydroxyethylidene diphosphoric acid from industrial grade hydroxyethylidene diphosphoric acid is achieved.

[0046] The anion and cation removal device used in Example 3 is a functional resin prepared by the method of Examples 1-2. The cationic resin / fiber of other embodiments includes one or more resins with polystyrene / divinylbenzene as the skeleton and grafted with sulfonic acid group, carboxyl group or quaternary amine group. The anionic resin / fiber has polystyrene / polysulfone as the skeleton and grafted with any one or more resins with sulfonic acid group. The raw materials are purchased from Lanxiao Technology, Purolite (China) Co., Ltd. and DuPont Company, etc.

[0047] Example 3 The ion exchange resin uses a functional resin with a particle size of less than 1 mm and a uniformity coefficient of less than 1.25. The ion exchange resins or fibers used in the anion and cation removal devices of other embodiments include, but are not limited to: sulfonic acid styrene resin / fiber, carboxyl styrene resin / fiber, quaternary amino styrene resin / fiber, perfluorosulfonic acid resin / fiber, sulfonated polyethersulfone resin / fiber, one or more of which are connected in series.

[0048] The filter membrane in the nanofilter is a polytetrafluoroethylene membrane with a pore size of 30 nm. The filter membranes in other embodiments are not limited to polytetrafluoroethylene membranes, but also include polyethersulfone membranes, polyvinylidene fluoride membranes, polyimide membranes, polyamide membranes, or one or more of these membranes in series, and the filter membrane pore size of the nanofilter is 10-50 nm.

[0049] In S3, a suspension stirring crystallizer is used, and the crystallization temperature is 78° C. In other embodiments, one or a combination of a plate crystallizer and a falling film crystallizer may be selected, and the crystallization temperature does not exceed 80° C.

[0050] S4 is specifically vacuum drying, and the drying temperature does not exceed 80°C.

[0051] The production method and device of electronic-grade hydroxyethylidene diphosphonic acid in Example 3 have short production process, low energy consumption, good separation effect, strong process continuity, high purity and low impurity content, which can meet the product requirements of purity mass content of more than 99% and single metal ion content of less than 10 ppb.

[0052] Example 4

[0053] refer to Figure 2 , industrial-grade hydroxyethylidene diphosphonic acid 1 and solvent isopropanol 2 from outside the boundary are mixed in a mass ratio of 1:1, the mass content of chelating agent tetrasodium ethylenediaminetetraacetate 3 in isopropanol solvent 2 is 20ppm, and enters into stirring and heating mixer 4 to dissolve into hydroxyethylidene diphosphonic acid solution 5, and the mass content of chelating agent tetrasodium iminodisuccinate in the solution is 1ppm; then enters into microfilter 6, which can use polytetrafluoroethylene membrane with pore size of 0.2μm and uniformity coefficient of 1.1, and removes particles larger than 0.2μm and then enters into anion and cation remover 8, which uses sulfonic acid styrene functional resin with particle size of 1mm and uniformity coefficient of 1.1 and particle size of 0.7mm and uniformity coefficient of 1.1. The present invention relates to a quaternary aminostyrene resin having a coefficient of 1.15, and the anions and cations in the o-hydroxyethylidene diphosphonic acid solution are removed. The anions and cations in the o-hydroxyethylidene diphosphonic acid solution 9 are removed. The anions and cations in the o-hydroxyethylidene diphosphonic acid solution 9 enters the nanofilter and is filtered out by the nanofilter 13 to remove particles larger than 10 nm. The filter membrane of the nanofilter 13 can adopt a polyvinylidene fluoride membrane (PVDF) with a pore size of 10 nm and a uniformity coefficient of 1.25. After filtering out particles larger than 10 nm, the filter enters the separator 12. The separator adopts a plate crystallizer, and the crystallization temperature is 197° C. and the crystallization pressure is normal pressure. The hydroxyethylidene diphosphonic acid 15 obtained by the separator passes through a vacuum dryer 16, and the vacuum drying pressure is 50 kPa and the vacuum drying temperature is 60° C., and then the product is obtained. The product indicators are shown in Table 2.

[0054] Example 5

[0055] refer to Figure 2, as shown in Table 1, the industrial-grade hydroxyethylidene diphosphoric acid feed 1 and the solvent water 2 are mixed in a mass ratio of 1:1, and the mass content of the chelating agent sodium tripolyphosphate 3 in the water solvent 2 is 10ppm, and enters the stirring and heating mixer 4 to dissolve into the hydroxyethylidene diphosphoric acid solution 5, and the mass content of the dechelating agent sodium tripolyphosphate in the solution is 5ppm; then enters the microfilter 6, and the microfilter can use a polytetrafluoroethylene membrane with a pore size of 0.1μm and a uniformity coefficient of 1.2. After removing particles with a particle size of 0.2μm or more, it enters the anion and cation remover 8, and the anion and cation remover uses sulfonated polyethersulfone fiber with a particle size of 0.9mm and a uniformity coefficient of 1.15 and perfluorosulfonic acid fiber with a particle size of 0.5mm, uniformity The perfluorosulfonic acid fiber with a coefficient of 1.25 is connected in series to remove the anions and cations in the o-hydroxyethylidene diphosphonic acid solution. The anions and cations removed hydroxyethylidene diphosphonic acid solution 9 enters the nanofilter 10 and is filtered out by the nanofilter 13 to remove particles larger than 10nm. The nanofilter 13 membrane can adopt a polyvinylidene fluoride membrane (PVDF) with a pore size of 20nm and a uniformity coefficient of 1.1. After filtering out particles larger than 10nm, it enters the separator 12. The separator adopts a falling film crystallizer, the crystallization temperature is: 196°C, and the crystallization pressure is normal pressure; the hydroxyethylidene diphosphonic acid 15 obtained by the separator passes through a vacuum dryer 16, the vacuum drying pressure is 30kpa, the vacuum drying temperature is 40°C, and then the product is obtained. The product indicators are shown in Table 2.

[0056] Comparative Example 1

[0057] Compared with Example 3, the chelating agent tetrasodium ethylenediaminetetraacetate was not added, and the rest was the same as Example 2. The product indicators are shown in Table 2.

[0058] Comparative Example 2

[0059] Compared with Example 4, the crystallization temperature is set to 185°C, and the others are the same as Example 3. The product indicators are shown in Table 2.

[0060] Test Example 1

[0061] The components in the hydroxyethylidene diphosphonic acid of Examples 3-4 and Comparative Examples 1-2 were tested for content. The testing instruments were: PerkinElmer ICP-OES / Avio550MAX for raw metal elements, Agilent ICP-MS / MS 8900 for product metal elements, and Agilent GC-MS gas chromatography for raw material and product content. The results are shown in Table 1-2.

[0062] Table 2. Product indicators after treatment

[0063]

[0064] The quality content of the hydroxyethylidene diphosphonic acid product produced by the method of the invention can reach more than 99%, and the content of each single metal ion (Li, K, Mg, Al, Ba, Cr, Mn, Fe, Co, Ni, Cu, Ti, Zn, Sn, Pb) is ≤10ppb or less, and Na and Ca are ≤50ppb or less, which meets the requirements of the semiconductor, aerospace, optoelectronics and other industries for hydroxyethylidene diphosphonic acid.

[0065] Although the present invention has been described in detail above by general description, specific implementation methods and experiments, it is obvious to those skilled in the art that some modifications or improvements can be made to the present invention. Therefore, these modifications or improvements made without departing from the spirit of the present invention all belong to the scope of protection claimed by the present invention.

Claims

1. A cation exchange resin, characterized in that The cation exchange resin is prepared by swelling a skeleton composed of a copolymer of styrene and vinylbenzene in a volume ratio of 5:1, acidifying with sulfuric acid and sulfate, and then washing to a pH value of 5-6.

2. An anion exchange resin, characterized in that The anion exchange resin is prepared by sequentially subjecting a skeleton composed of a copolymer of styrene and vinylbenzene in a volume ratio of 5:1 to chloromethylation and amination.

3. An anion and cation removal device, characterized in that: The anion and cation removal device comprises the cation exchange resin as claimed in claim 1 and the anion exchange resin as claimed in claim 2.

4. A method for purifying electronic grade high-purity hydroxyethylidene diphosphonic acid, characterized in that: The method comprises the following steps: Dissolving step: dissolving the industrial grade hydroxyethylidene diphosphonic acid raw material uniformly; Filtration step: passing the industrial-grade hydroxyethylidene diphosphonic acid solution through a microfilter to remove large particles, passing through an anion and cation removal device as claimed in claim 3 to remove anions and cations, and passing through a nanofilter to remove microparticles; Crystallization step: subjecting the hydroxyethylidene diphosphonic acid solution after removing the microparticles to crystallization treatment to obtain electronic grade high-purity hydroxyethylidene diphosphonic acid crystals; Drying step: drying the electronic grade high-purity hydroxyethylidene diphosphonic acid crystals; In the industrial-grade hydroxyethylidene diphosphoric acid raw material, the purity of hydroxyethylidene diphosphoric acid is above 97% by mass, the mass content of phosphoric acid is below 0.5%, the mass content of phosphorous acid is below 0.8%, the mass content of chloride is below 100ppm, and the mass content of iron is below 10ppm.

5. The method for purifying electronic grade high-purity hydroxyethylidene diphosphonic acid according to claim 4, characterized in that: The dissolving step specifically comprises introducing industrial-grade hydroxyethylidene diphosphonic acid, a solvent and a chelating agent into a stirring and heating mixer to dissolve into a hydroxyethylidene diphosphonic acid solution; the temperature of the stirring and heating mixer does not exceed 80°C.

6. The method for purifying electronic grade high-purity hydroxyethylidene diphosphonic acid according to claim 5, characterized in that: The solvent in the dissolving step includes but is not limited to water, methanol, ethanol, n-propanol, isopropanol, acetone, methyl acetate, ethyl acetate, etc., or a mixture of several of them; the chelating agent in the dissolving step includes but is not limited to tetrasodium ethylenediaminetetraacetic acid, ethylenediaminetetraacetic acid, sodium tripolyphosphate, tetrasodium iminodisuccinate, trisodium nitrilotriacetic acid, ethylenediaminetetraacetic acid, aminotriacetic acid, diethylenetriaminepentaacetic acid, polyaspartic acid, citric acid, or a mixture of several of them.

7. The method for purifying electronic grade high-purity hydroxyethylidene diphosphonic acid according to claim 6, characterized in that: The nanofilter includes but is not limited to one or more of polytetrafluoroethylene membrane, polyethersulfone membrane, polyvinylidene fluoride membrane, polyimide membrane, and polyamide membrane connected in series, and the pore size of the filter membrane of the nanofilter is 10-50nm.

8. The method for purifying electronic grade high-purity hydroxyethylidene diphosphonic acid according to claim 4, characterized in that: In the crystallization step, one or a combination of a suspended stirring crystallizer, a plate crystallizer and a falling film crystallizer is used, and the crystallization temperature does not exceed 80°C.

9. The method for purifying electronic grade high-purity hydroxyethylidene diphosphonic acid according to claim 4, characterized in that: The drying step is specifically vacuum drying, and the drying temperature does not exceed 80°C.

10. The anion and cation removal device according to claim 3, characterized in that: The cation exchange resin of the anion and cation removal device includes one or more resins with polystyrene-divinylbenzene as the skeleton and grafted with sulfonic acid groups, carboxyl groups or quaternary amine groups. The anion exchange resin includes any one or more resins with polystyrene-polysulfone as the skeleton and grafted with sulfonic acid groups. The anion exchange resin or cation exchange resin uses a functional resin with a particle size of less than 1 mm and a uniformity coefficient of less than 1.25.

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