A method for producing electronic grade phosphoric acid by combining resin-electrolysis and in situ regeneration of the resin

Abstract

The present application belongs to the field of electronic grade phosphoric acid preparation, and discloses a method for preparing electronic grade phosphoric acid by combining resin and electrolysis and regenerating resin in situ. The method uses a membrane two-chamber ultra-pure plate-frame electrolysis device containing an anion exchange membrane, and the anode storage tank is provided with cation exchange resin. The electronic grade phosphoric acid is prepared by using the selective permeability of the anion exchange membrane and the adsorption of metal ions by the cation exchange resin. Meanwhile, the cation exchange resin can be regenerated by using the phosphoric acid solution generated by the anode, and the phosphoric acid solution can be used as raw material for electrolysis after regeneration. The method uses the selective permeability of the anion exchange membrane and the adsorption of metal ions by the cation exchange resin to remove the metal ions which are difficult to remove by conventional methods from the phosphoric acid aqueous solution, and prepares electronic grade phosphoric acid products.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of electronic grade phosphoric acid preparation, and more particularly relates to a method for preparing electronic grade phosphoric acid by combining resin and electrolysis and regenerating resin in situ. BACKGROUND

[0002] Electronic grade phosphoric acid aqueous solution is widely used in microelectronic industry such as ultra large scale integrated circuit, large screen liquid crystal display, and is mainly used for wet cleaning and wet etching of chips. The content of metal ions in phosphoric acid has a great influence on the yield of finished products. For example, alkali metal impurities can dissolve into the oxide film, resulting in a decrease in insulation voltage. Heavy metal impurities attached to the surface of the wafer can cause a decrease in P-N junction voltage. The attachment of impurity molecules or ions can also cause corrosion or leakage and other faults.

[0003] Electronic grade ultra-pure reagents are mostly prepared by coupling processes such as distillation, rectification, membrane filtration, ion exchange, extraction, and crystallization. Correspondingly, the current methods for preparing electronic grade phosphoric acid include H3P decomposition method, phosphoric acid triester hydrolysis method, and yellow phosphorus combustion one-step method.

[0004] Electrolytic preparation of electronic grade phosphoric acid utilizes the selective permeability of anion exchange membrane to anions such as dihydrogen phosphate, monohydrogen phosphate and phosphate to purify phosphoric acid. However, the technical personnel found that the effect of removing part of the high-valence metal in phosphoric acid by electrolysis is poor. Strong acid cation exchange resin has strong acid groups such as sulfonic acid groups (—SO3H) on it. The H + ions dissociated therefrom can be ion exchanged with equivalent metal cations, thereby achieving the purpose of adsorbing and removing metal ions. Chelating resin is a cross-linked functional polymer compound that can form a multi-site complex with metal ions. The functional atomic groups on this type of resin can undergo coordination reaction with metal ions, thereby forming a stable structure similar to small molecule chelates, achieving the purpose of adsorbing and removing metal ions. Meanwhile, metal ions act as acid (i.e. electron acceptor) and functional groups in resin act as base (i.e. electron donor) following the Lewis acid-base electron theory, i.e. strong base reacts with strong acid first and weak base reacts with weak acid first. The more charges a metal ion has and the smaller its radius, the greater the ion potential Zeff / r, the greater the tendency to attract electron pairs, the stronger the acidity, and the stronger the adsorption capacity of the resin. That is, the resin can adsorb and remove high-valence metal cations in phosphoric acid which have poor electrolytic removal effect.

[0005] Since the essence of removing metal cations by resin is ion exchange equilibrium, i.e. in the regeneration process of the resin, H + in the acid exchanges with metal cations in the resin, the metal cations are dissolved into the solution, and H + ions are re-adsorbed in the resin. Therefore, a large amount of acid is required for the regeneration of the resin, which in turn generates a large amount of waste acid, and the treatment process is complex, energy-consuming, and causes resource waste.

[0006] Therefore, it is urgent to provide a method for preparing electronic-grade phosphoric acid by combining resin and electrolysis and regenerating resin in situ. SUMMARY

[0007] The present application aims at solving the problems of the prior art and provides a method for preparing electronic-grade phosphoric acid by combining resin and electrolysis and regenerating resin in situ. The present application removes metal ions that are difficult to remove by conventional methods from phosphoric acid aqueous solution by using the selective permeability of anion exchange membrane and the adsorption of metal ions by cation exchange resin, and electrolytically prepares electronic-grade phosphoric acid product.

[0008] To achieve the above-mentioned purpose, the present application provides a method for preparing electronic-grade phosphoric acid by combining resin and electrolysis and regenerating resin in situ, which comprises the following steps:

[0009] S1: impurity removal by resin pretreatment;

[0010] S2: injecting phosphoric acid aqueous solution raw material A into the cathode liquid storage tank of the electrolysis system, injecting ultrapure water into the anode liquid storage tank containing the pretreated impurity removal resin and / or regenerated resin of step S1, and connecting the power supply to perform dynamic circulation electrolysis; the anions generated by the ionization of the phosphoric acid aqueous solution raw material A in the cathode liquid storage tank pass through the cathode chamber, the anion exchange membrane and the anode chamber of the electrolysis system in sequence under the action of the electric field, and combine with the hydrogen ions generated by anode electrolysis to generate first purified phosphoric acid; the resin in the anode liquid storage tank adsorbs and removes metal cations in the first purified phosphoric acid; when the mass concentration of the phosphoric acid aqueous solution B in the anode liquid storage tank reaches a first threshold value, the dynamic circulation electrolysis is stopped, and an electronic-grade phosphoric acid product is obtained;

[0011] S3: resin regeneration:

[0012] After the electronic-grade phosphoric acid product obtained in step S2 is discharged from the electrolysis system, ultrapure water is injected into the anode liquid storage tank to mix with the resin after use in step S2; an industrial-grade phosphoric acid raw material solution is injected into the cathode liquid storage tank, and the power supply is connected to perform dynamic circulation electrolysis; the anions generated by the ionization of the phosphoric acid raw material in the cathode liquid storage tank pass through the cathode chamber, the anion exchange membrane and the anode chamber in sequence under the action of the electric field, and combine with the hydrogen ions generated by anode electrolysis to generate first purified phosphoric acid; the first purified phosphoric acid is used to desorb and regenerate the resin in the anode liquid storage tank; when the mass concentration of the phosphoric acid aqueous solution C in the anode liquid storage tank is higher than a second threshold value, the dynamic circulation electrolysis is stopped;

[0013] The phosphoric acid aqueous solution C in the anode liquid storage tank and the remaining phosphoric acid aqueous solution in the cathode liquid storage tank are discharged from the electrolysis system, ultrapure water is injected into the anode liquid storage tank and the cathode liquid storage tank, and circulation flushing is performed until the metal element content in the cleaning liquid is lower than a third threshold value, and the regenerated resin is obtained.

[0014] According to the present application, preferably, as shown in the drawings, the electrolysis system comprises an electrolytic cell, the anion exchange membrane, the anolyte storage tank, the catholyte storage tank and the power supply; Figure 1

[0015] The anion exchange membrane is used to divide the electrolytic cell into the anode chamber and the cathode chamber;

[0016] The anode chamber and the cathode chamber are respectively provided with an anode sheet and a cathode sheet;

[0017] The catholyte storage tank is provided with a first conduit and a second conduit, one end of the first conduit is close to the bottom of the catholyte storage tank, the other end is close to the bottom of the anode chamber through a cathode peristaltic pump; one end of the second conduit is close to the top of the cathode chamber, the other end is close to the top of the catholyte storage tank;

[0018] The anolyte storage tank is provided with a third conduit and a fourth conduit, one end of the third conduit is close to the bottom of the anolyte storage tank, the other end is close to the bottom of the anode chamber through an anode peristaltic pump; one end of the fourth conduit is close to the top of the anode chamber, the other end is close to the top of the anolyte storage tank;

[0019] The positive and negative electrodes of the power supply are respectively electrically connected with the anode sheet and the cathode sheet.

[0020] In the present application, the first conduit, the second conduit, the third conduit, the fourth conduit, the anode peristaltic pump and the cathode peristaltic pump are arranged to realize the feeding and discharging of the electrolytic cell in the feeding and discharging mode from bottom to top.

[0021] In the present application, the anode peristaltic pump and the cathode peristaltic pump are used to realize the dynamic circulation electrolysis and the circulation flushing in the resin pretreatment impurity removal and regeneration method.

[0022] According to the present application, preferably, the electrolytic cell is an ultra-pure plate-frame electrolytic cell.

[0023] According to the present application, preferably, the material of the electrolytic cell is at least one of ultra-pure polytetrafluoroethylene and fluorinated alkyl vinyl ether copolymer, ultra-pure high-density polyethylene and ultra-pure polytetrafluoroethylene, preferably ultra-pure polytetrafluoroethylene and fluorinated alkyl vinyl ether copolymer.

[0024] According to the present application, preferably, the anion exchange membrane is a quaternary amine base type anion exchange membrane.

[0025] According to the present application, preferably, the anode sheet and the cathode sheet are each independently a platinum electrode with a purity of greater than 99.9%, preferably a platinum electrode with a purity of greater than 99.999%.

[0026] According to the present application, preferably, the distance between the anode sheet and the cathode sheet is 0.5-3.0 cm.​

[0027] According to the application, preferably, the resin is a cation exchange resin, preferably at least one of a strong acid styrene type cation exchange resin, a macroporous strong acid cation exchange resin and a macroporous chelate type cation exchange resin.

[0028] In the application, the resin is always kept in the anolyte tank.

[0029] According to the application, preferably, the method for removing impurities by pretreating the resin comprises:

[0030] The resin and ultrapure water are injected into the anolyte tank, an industrial-grade phosphoric acid raw solution is injected into the catholyte tank, and a power supply is turned on for dynamic circulating electrolysis; the anions generated by ionization of the phosphoric acid raw material in the catholyte tank pass through the cathode chamber, the anion exchange membrane and reach the anode chamber in turn under the action of the electric field, and combine with the hydrogen ions generated by anode electrolysis to generate first-purified phosphoric acid; the first-purified phosphoric acid is used to pretreat and remove impurities from the resin in the anolyte tank; when the mass concentration of the phosphoric acid aqueous solution D in the anolyte tank is higher than a second threshold value, the dynamic circulating electrolysis is stopped.

[0031] The phosphoric acid aqueous solution D in the anolyte tank and the remaining phosphoric acid aqueous solution in the catholyte tank are discharged from the electrolysis system, ultrapure water is injected into the anolyte tank and the catholyte tank, and a cycle flushing is performed until the content of metal elements in the cleaning liquid is lower than a third threshold value, and the pretreatment and removal of impurities of the resin are completed.

[0032] According to the application, preferably, the first threshold value is 39.5%-40.5%.

[0033] According to the application, preferably, the second threshold value is 55%-65%.

[0034] According to the application, preferably, the third threshold value is 0.08-0.12 ppb.

[0035] According to the application, preferably, the concentration of the phosphoric acid aqueous solution raw material A is 20%-39%.

[0036] The phosphoric acid aqueous solution raw material A is at least one of an industrial-grade phosphoric acid raw solution, a phosphoric acid aqueous solution C with a mass concentration reaching a second threshold value in step S3, and a phosphoric acid aqueous solution D with a mass concentration reaching a second threshold value after the pretreatment and removal of impurities of the resin.

[0037] According to the application, preferably, the anion is at least one of dihydrogen phosphate, monohydrogen phosphate and phosphate.

[0038] In the application, the mass concentration of the industrial-grade phosphoric acid raw solution is 20%-35%.

[0039] According to the application, preferably, the dynamic circulation electrolysis is constant current electrolysis, and preferably, the current density is 500-2000 A / m 2 .

[0040] According to the application, preferably, the solution flow rate in the cathode chamber and the anode chamber of the electrolysis system is 0.5-3.5 m / min.

[0041] According to the application, preferably, the temperature in the dynamic circulation electrolysis, the anolyte storage tank and the catholyte storage tank is independently 30-60℃.

[0042] According to the application, preferably, the content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb, and the mass concentration of phosphoric acid is 39.5%-40.5%.

[0043] The beneficial effects of the technical scheme of the application are as follows:

[0044] The application utilizes the selective permeability of anion exchange membrane and the adsorption of metal ions by cation exchange resin to remove metal ions in the phosphoric acid aqueous solution which are difficult to remove by conventional methods, and to prepare electronic grade phosphoric acid products by electrolysis. The electrochemical method is applied to the preparation process of ultrapure reagents, which simplifies the preparation process of ultrapure reagents, and the raw materials and products are completely separated in the method, which meets the requirements of clean production.

[0045] Meanwhile, according to the ion exchange balance principle of resin adsorption and desorption, the cation exchange resin can be desorbed and pretreated by purified phosphoric acid to remove impurities and regenerate. After the removal and regeneration are completed, the obtained phosphoric acid aqueous solution can be used as the phosphoric acid aqueous solution raw material A again. Compared with some previous processes, the operation is simple, the raw materials and products are completely separated, the resin regeneration does not produce waste acid and waste alkali, and the process is clean and pollution-free, which is suitable for large-scale production.

[0046] The method can realize continuous production, greatly reduce the use of high-power heating equipment, and does not produce waste acid and waste alkali, thereby solving the pollution and energy consumption problems of traditional processes, and reducing the production cost.

[0047] Other features and advantages of the application will be described in detail in the following specific embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0048] The above and other objects, features and advantages of the present application will become more apparent from the following detailed description when taken in conjunction with the accompanying drawings in which similar reference characters refer to similar features throughout the several views, and in which:

[0049] Figure 1A schematic diagram of an electrolysis system used in a method for preparing electronic-grade phosphoric acid by combining resin-electrolysis and in-situ resin regeneration provided by the present application is shown.

[0050] The reference signs are explained as follows: 1 - electrolytic cell; 2 - cathode liquid storage tank; 3 - cathode liquid peristaltic pump; 4 - anode liquid storage tank; 5 - anode liquid peristaltic pump; 6 - anion exchange membrane; 7 - cathode chamber; 8 - cathode sheet; 9 - anode chamber; 10 - anode sheet; 11 - power supply; 12 - first conduit; 13 - second conduit; 14 - third conduit; 15 - fourth conduit. DETAILED DESCRIPTION

[0051] The preferred embodiments of the present application will be described in more detail below. Although the preferred embodiments of the present application are described below, it is understood that the present application can be implemented in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that the present application will be thorough and complete, and will fully convey the scope of the present application to those skilled in the art.

[0052] In the following examples, the content of metal elements (including Na, K, Ag, Ca, Cu, Zn, Ni, Pb, Mn, Al, Fe, Cr) in the electronic-grade phosphoric acid product obtained in step S2 is quantitatively analyzed by inductively coupled plasma mass spectrometry (ICP-MS).

[0053] Example 1

[0054] The present embodiment provides a method for preparing electronic-grade phosphoric acid by combining resin-electrolysis and in-situ resin regeneration, which is performed in the system shown in Figure 1 as shown in Figure 1 The electrolysis system comprises an electrolytic cell 1, an anion exchange membrane 6, an anode liquid storage tank 4, a cathode liquid storage tank 2, and a power supply 11.

[0055] The anion exchange membrane 6 is used to divide the electrolytic cell 1 into the anode chamber 9 and the cathode chamber 7.

[0056] The anode chamber 9 and the cathode chamber 7 are respectively provided with an anode sheet 10 and a cathode sheet 8.

[0057] The cathode liquid storage tank 2 is provided with a first conduit 12 and a second conduit 13. One end of the first conduit 12 is close to the bottom of the cathode liquid storage tank, and the other end is close to the bottom of the cathode chamber through the cathode peristaltic pump 3. One end of the second conduit 13 is close to the top of the cathode chamber, and the other end is close to the top of the cathode liquid storage tank.

[0058] The anolyte storage tank 4 is provided with a third conduit 14 and a fourth conduit 15, one end of the third conduit 14 is close to the bottom of the anolyte storage tank, the other end is close to the bottom of the anode chamber through the anode peristaltic pump 5; one end of the fourth conduit 15 is close to the top of the anode chamber, the other end is close to the top of the anolyte storage tank;

[0059] The positive and negative poles of the power supply 11 are respectively electrically connected with the anode sheet and the cathode sheet.

[0060] The electrolytic cell 1 is an ultrapure plate frame electrolytic cell; the material of the electrolytic cell is ultrapure polytetrafluoroethylene and fluorine alkyl vinyl ether copolymer;

[0061] The anion exchange membrane 6 is a quaternary amine base type anion exchange membrane;

[0062] The anode sheet 10 and the cathode sheet 8 are each independently a platinum electrode with a purity of greater than 99.999%;

[0063] The distance between the anode sheet and the cathode sheet is 1.5m.

[0064] Comprising the following steps:

[0065] S1: resin desorption pretreatment impurity removal, comprising: injecting strong acid styrene type cation exchange resin and ultrapure water into the anolyte storage tank, injecting industrial grade phosphoric acid raw solution into the catholyte storage tank, and connecting the power supply to perform dynamic circulating electrolysis; The anions generated by the ionization of the phosphoric acid raw material in the catholyte storage tank pass through the cathode chamber, the anion exchange membrane and reach the anode chamber under the action of the electric field in turn, and the hydrogen ions generated by anode electrolysis combine to generate first purified phosphoric acid; The first purified phosphoric acid is used for pretreatment and impurity removal of the resin in the anolyte storage tank; When the mass concentration of the phosphoric acid aqueous solution D in the anolyte storage tank is higher than 60%, the dynamic circulating electrolysis is stopped;

[0066] The phosphoric acid aqueous solution D in the anolyte storage tank and the remaining phosphoric acid aqueous solution in the catholyte storage tank are discharged from the electrolysis system, and ultrapure water is injected into the anolyte storage tank and the catholyte storage tank, and the circulation flushing is carried out until the metal element content in the cleaning liquid is lower than 0.1ppb, and the resin pretreatment impurity removal is completed.

[0067] The reaction conditions of step S1 include: the temperature of the anode and cathode storage tank is 40℃; the flow rate of the peristaltic pump is 0.5m / min, and the constant current density is 1500A / m 2 .

[0068] S2: 250 mL of the phosphoric acid aqueous solution raw material A with a concentration of 25% is injected into the cathode liquid storage tank of the electrolysis system, 100 mL of ultrapure water and 50 mL of the resin after impurity removal in pretreatment are injected into the anode liquid storage tank of the electrolysis system, and the power supply is turned on to perform dynamic circulation electrolysis. The anions generated by ionization of the phosphoric acid aqueous solution raw material A in the cathode liquid storage tank combine with hydrogen ions generated by anode electrolysis to generate first-purified phosphoric acid under the action of an electric field. The resin in the anode liquid storage tank adsorbs and removes metal cations in the first-purified phosphoric acid. When the mass concentration of the phosphoric acid aqueous solution B in the anode liquid storage tank reaches 40%, the dynamic circulation electrolysis is stopped, and the solutions in the anode chamber and the cathode chamber are pumped into the anode liquid storage tank and the cathode liquid storage tank, respectively, to obtain an electronic-grade phosphoric acid product. The content of various metal elements in the electronic-grade phosphoric acid product is less than 0.1 ppb.

[0069] The reaction conditions of step S2 include that the temperature of the anode and cathode liquid storage tanks is 40°C, the flow rate of the peristaltic pump is 2 m / min, and the constant current density is 1500 A / m 2 .

[0070] S3: Resin regeneration

[0071] After the electronic-grade phosphoric acid product obtained in step S2 is discharged from the electrolysis system, ultrapure water is injected into the anode liquid storage tank to mix with the resin after use in step S2. An industrial-grade phosphoric acid raw material solution is injected into the cathode liquid storage tank, and the power supply is turned on to perform dynamic circulation electrolysis. The anions generated by ionization of the phosphoric acid raw material in the cathode liquid storage tank combine with hydrogen ions generated by anode electrolysis to generate first-purified phosphoric acid under the action of an electric field. The resin in the anode liquid storage tank is desorbed and regenerated by the first-purified phosphoric acid. When the mass concentration of the phosphoric acid aqueous solution C in the anode liquid storage tank is higher than 60%, the dynamic circulation electrolysis is stopped, and the phosphoric acid aqueous solution C in the anode liquid storage tank and the remaining phosphoric acid aqueous solution in the cathode liquid storage tank are discharged from the electrolysis system. Ultrapure water is injected into the anode liquid storage tank and the cathode liquid storage tank, and the circulation washing is performed until the content of metal elements in the washing liquid is lower than a third threshold value to obtain the regenerated resin. Step S2 can be continued.

[0072] The reaction conditions of step S3 include that the temperature of the anode and cathode liquid storage tanks is 40°C, the flow rate of the peristaltic pump is 0.5 m / min, and the constant current density is 1500 A / m 2 , and the dynamic circulation electrolysis is started.

[0073] Example 2

[0074] The embodiment provides a method for preparing electronic-grade phosphoric acid by combining resin and electrolysis and regenerating the resin in situ. The difference between the embodiment and example 1 is only that:

[0075] The resin is a macroporous strong acid cation exchange resin.

[0076] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0077] Example 3

[0078] The present example provides a method for preparing electronic grade phosphoric acid by combining resin and electrolysis and regenerating the resin in situ. The difference between the present example and Example 1 is that in step S2, the concentration of the phosphoric acid aqueous solution raw material A is 20%.

[0079] The resin is a macroporous chelating cation exchange resin.

[0080] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0081] Example 4

[0082] The present example provides a method for preparing electronic grade phosphoric acid by combining resin and electrolysis and regenerating the resin in situ. The difference between the present example and Example 1 is that in step S2, the concentration of the phosphoric acid aqueous solution raw material A is 20%.

[0083] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0084] Example 5

[0085] The present example provides a method for preparing electronic grade phosphoric acid by combining resin and electrolysis and regenerating the resin in situ. The difference between the present example and Example 1 is that in step S2, the concentration of the phosphoric acid aqueous solution raw material A is 35%.

[0086] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0087] Example 6

[0088] The present example provides a method for preparing electronic grade phosphoric acid by combining resin and electrolysis and regenerating the resin in situ. The difference between the present example and Example 1 is that in step S2,

[0089] The concentration of the phosphoric acid aqueous solution raw material A is 30%;

[0090] The constant current density is set to 750 A / m 2 .

[0091] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0092] Example 7

[0093] The embodiment provides a method for preparing electronic-grade phosphoric acid by combining resin-electrolysis and in-situ resin regeneration, and the difference between the embodiment and the embodiment 1 is that in the step S2,

[0094] The concentration of the phosphoric acid aqueous solution raw material A is 30%;

[0095] The constant current density is set to be 1250 A / m 2 .

[0096] The content of various metal elements in the obtained electronic-grade phosphoric acid product is lower than 0.1 ppb.

[0097] Embodiment 8

[0098] The embodiment provides a method for preparing electronic-grade phosphoric acid by combining resin-electrolysis and in-situ resin regeneration, and the difference between the embodiment and the embodiment 1 is that in the step S2,

[0099] The concentration of the phosphoric acid aqueous solution raw material A is 30%;

[0100] The constant current density is set to be 1750 A / m 2 .

[0101] The content of various metal elements in the obtained electronic-grade phosphoric acid product is lower than 0.1 ppb.

[0102] Embodiment 9

[0103] The embodiment provides a method for preparing electronic-grade phosphoric acid by combining resin-electrolysis and in-situ resin regeneration, and the difference between the embodiment and the embodiment 1 is that in the step S2,

[0104] The concentration of the phosphoric acid aqueous solution raw material is 35%;

[0105] The flow rate of the peristaltic pump is set to be 0.5 m / min, and the peristaltic pump is started;

[0106] The constant current density is set to be 1000 A / m 2 .

[0107] The content of various metal elements in the obtained electronic-grade phosphoric acid product is lower than 0.1 ppb.

[0108] Embodiment 10

[0109] The embodiment provides a method for preparing electronic-grade phosphoric acid by combining resin-electrolysis and in-situ resin regeneration, and the difference between the embodiment and the embodiment 1 is that in the step S2,

[0110] The concentration of the phosphoric acid aqueous solution raw material A is 30%;

[0111] The flow rate of the peristaltic pump is set to be 1.5 m / min, and the peristaltic pump is started;

[0112] The constant current density is set to 1000 A / m 2 .

[0113] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0114] Example 11

[0115] The difference between this embodiment and Example 1 is only that in step S2,

[0116] The concentration of the phosphoric acid aqueous solution raw material A is 30%;

[0117] The constant current density is set to 1000 A / m 2 .

[0118] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0119] Example 12

[0120] The difference between this embodiment and Example 1 is only that in step S2,

[0121] The temperature of dynamic circulation electrolysis and the temperature of the cathode and anode storage tanks are set to 30℃;

[0122] The concentration of the phosphoric acid aqueous solution raw material A is 35%;

[0123] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0124] Example 13

[0125] The difference between this embodiment and Example 1 is only that in step S2,

[0126] The temperature of dynamic circulation electrolysis and the temperature of the cathode and anode storage tanks are set to 60℃;

[0127] The concentration of the phosphoric acid aqueous solution raw material A is 35%;

[0128] The content of various metal elements in the electronic grade phosphoric acid product is less than 0.1 ppb.

[0129] Comparative Example 1

[0130] The present comparative example provides a method for preparing electronic grade phosphoric acid by electrolysis. The present comparative example is only different from example 1 in that only step S2 is included, and in step S2 only 100 mL of ultrapure water is injected into the anolyte storage tank of the electrolysis system; the reaction conditions are unchanged.

[0131] The contents of Na, K, Ag, Ca, Zn, Ni, Pb, Mn, Cr in the obtained electronic grade phosphoric acid product are all lower than 0.1 ppb, but the contents of Cu, Al, Fe are higher than 20 ppb.

[0132] The above has described various embodiments of the present application, the above description is exemplary, not exhaustive, and is not limited to the disclosed embodiments. Many modifications and changes are obvious to those skilled in the art without departing from the scope and spirit of the described embodiments.

Claims

1. A process for the production of electronic grade phosphoric acid by a combination of resin-electrolytic process and in situ regeneration of the resin, characterized by, The method comprises the following steps: S1: resin pretreatment impurity removal; The method for resin pretreatment impurity removal comprises: The resin and ultrapure water are injected into the anolyte storage tank, the industrial-grade phosphoric acid raw material solution is injected into the catholyte storage tank, and the power supply is turned on to perform dynamic circulation electrolysis; the anions generated by ionization of the phosphoric acid raw material in the catholyte storage tank pass through the cathode chamber, the anion exchange membrane and the anode chamber in turn under the action of the electric field, and combine with the hydrogen ions generated by anode electrolysis to generate first-purified phosphoric acid; the resin in the anolyte storage tank is pretreated and impurity-removed by the first-purified phosphoric acid; when the mass concentration of the phosphoric acid aqueous solution D in the anolyte storage tank is higher than the second threshold value, the dynamic circulation electrolysis is stopped; The phosphoric acid aqueous solution D in the anolyte storage tank and the residual phosphoric acid aqueous solution in the catholyte storage tank are discharged from the electrolysis system, ultrapure water is injected into the anolyte storage tank and the catholyte storage tank, and circulation flushing is performed until the content of metal elements in the cleaning liquid is lower than the third threshold value, and the resin pretreatment impurity removal is completed; S2: the phosphoric acid aqueous solution raw material A is injected into the catholyte storage tank of the electrolysis system, the ultrapure water is injected into the anolyte storage tank containing the pretreatment impurity-removed resin and / or regenerated resin of step S1, and the power supply is turned on to perform dynamic circulation electrolysis; the anions generated by ionization of the phosphoric acid aqueous solution raw material A in the catholyte storage tank pass through the cathode chamber, the anion exchange membrane and the anode chamber of the electrolysis system in turn under the action of the electric field, and combine with the hydrogen ions generated by anode electrolysis to generate first-purified phosphoric acid; the resin in the anolyte storage tank adsorbs and removes the metal cations in the first-purified phosphoric acid; when the mass concentration of the phosphoric acid aqueous solution B in the anolyte storage tank reaches the first threshold value, the dynamic circulation electrolysis is stopped, and the electronic-grade phosphoric acid product is obtained; S3: resin regeneration: After the electronic-grade phosphoric acid product obtained in step S2 is discharged from the electrolysis system, the ultrapure water is injected into the anolyte storage tank to mix with the resin used in step S2; the industrial-grade phosphoric acid raw material solution is injected into the catholyte storage tank, and the power supply is turned on to perform dynamic circulation electrolysis; the anions generated by ionization of the phosphoric acid raw material in the catholyte storage tank pass through the cathode chamber, the anion exchange membrane and the anode chamber in turn under the action of the electric field, and combine with the hydrogen ions generated by anode electrolysis to generate first-purified phosphoric acid; the resin in the anolyte storage tank is desorbed and regenerated by the first-purified phosphoric acid; when the mass concentration of the phosphoric acid aqueous solution C in the anolyte storage tank is higher than the second threshold value, the dynamic circulation electrolysis is stopped; The phosphoric acid aqueous solution C in the anolyte storage tank and the residual phosphoric acid aqueous solution in the catholyte storage tank are discharged from the electrolysis system, ultrapure water is injected into the anolyte storage tank and the catholyte storage tank, and circulation flushing is performed until the content of metal elements in the cleaning liquid is lower than the third threshold value, and the regenerated resin is obtained; The phosphoric acid aqueous solution raw material A is at least one of an industrial-grade phosphoric acid raw material solution, a phosphoric acid aqueous solution C with a mass concentration reaching the second threshold value in step S3, and a phosphoric acid aqueous solution D with a mass concentration reaching the second threshold value after resin pretreatment impurity removal; The first threshold value is 39.5%-40.5%; The second threshold value is 55%-65%; The third threshold value is 0.08-0.12 ppb.

2. The process for the production of electronic grade phosphoric acid by resin-electrodic combination and in situ regeneration of the resin as claimed in claim 1 wherein, The electrolysis system comprises an electrolytic cell, the anion exchange membrane, the anolyte storage tank, the catholyte storage tank and the power supply; The anion exchange membrane is used to divide the electrolytic cell into the anode chamber and the cathode chamber; The anode chamber and the cathode chamber are respectively provided with an anode sheet and a cathode sheet; The catholyte storage tank is provided with a first conduit and a second conduit, one end of the first conduit is close to the bottom of the catholyte storage tank, and the other end is close to the bottom of the anode chamber through a cathode peristaltic pump; one end of the second conduit is close to the top of the cathode chamber, and the other end is close to the top of the catholyte storage tank; The anolyte storage tank is provided with a third conduit and a fourth conduit, one end of the third conduit is close to the bottom of the anolyte storage tank, and the other end is close to the bottom of the anode chamber through an anode peristaltic pump; one end of the fourth conduit is close to the top of the anode chamber, and the other end is close to the top of the anolyte storage tank; The positive and negative electrodes of the power supply are respectively electrically connected with the anode sheet and the cathode sheet.

3. The method of claim 2, wherein the resin-electrolysis combined preparation of electronic-grade phosphoric acid and in-situ regeneration of resin is characterized in that, The electrolytic cell is an ultra-pure plate-frame electrolytic cell; The material of the electrolytic cell is at least one of ultra-pure polytetrafluoroethylene and fluorine alkyl vinyl ether copolymer, ultra-pure high-density polyethylene and ultra-pure polytetrafluoroethylene; The anion exchange membrane is a quaternary amine base type anion exchange membrane; The anode sheet and the cathode sheet are each independently a platinum electrode with a purity of greater than 99.9%; The distance between the anode sheet and the cathode sheet is 0.5-3.0 cm.

4. The process for the resin-electrodialytic production of electronic grade phosphoric acid with in situ regeneration of the resin according to claim 1, wherein, The resin is a cation exchange resin.

5. The process for the production of electronic grade phosphoric acid by resin-electrodic combination and in situ regeneration of the resin as claimed in claim 4 wherein, The resin is at least one of a strong acid styrene type cation exchange resin, a macroporous strong acid cation exchange resin and a macroporous chelate type cation exchange resin.

6. The process for the resin-electrodialytic production of electronic grade phosphoric acid with in situ regeneration of the resin according to claim 1, wherein, The concentration of the phosphoric acid aqueous solution raw material A is 20%-39%.

7. The process for the resin-electrodialytic production of electronic grade phosphoric acid with in situ regeneration of the resin according to claim 1, wherein, The anion is at least one of dihydrogen phosphate, monohydrogen phosphate and phosphate.

8. The method of claim 1, wherein the resin-electrolysis combined preparation of electronic-grade phosphoric acid and in-situ regeneration of resin is characterized in that, The dynamic circulation electrolysis is constant current electrolysis; The solution flow rate in the cathode chamber and the anode chamber in the electrolysis system is 0.5-3.5 m / min; The temperature in the dynamic circulation electrolysis, the anolyte storage tank and the catholyte storage tank is independently 30-60℃.

9. The method of claim 8, wherein the resin-electrolysis combined preparation of electronic-grade phosphoric acid and in-situ regeneration of resin is characterized in that, The current density of the dynamic circulation electrolysis is 500-2000 A / m 2 .

10. The process for the production of electronic grade phosphoric acid by resin-electrodialysis combination and in situ regeneration of the resin according to any one of claims 1 to 9, wherein, The content of various metal elements in the electronic-grade phosphoric acid product is less than 0.1 ppb, and the mass concentration of phosphoric acid is 39.5%-40.5%.

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