Method for preparing electronic grade sulfuric acid

Abstract

The invention relates to the technical field of electronic-grade sulfuric acid, and discloses a method for preparing electronic-grade sulfuric acid. Industrial-grade liquid sulfur trioxide is subjected to gasification, demisting, dehumidification and purification to prepare ultra-pure sulfur trioxide; absorbing sulfur trioxide by using electronic-grade sulfuric acid to prepare an electronic-grade sulfuric acid crude product; the electronic-grade sulfuric acid crude product is subjected to degassing, hydrogen type macroporous cation resin modification and continuous multi-group high-efficiency membrane combined filtration to obtain electronic-grade sulfuric acid; according to the modified hydrogen type macroporous cationic resin disclosed by the invention, the surface characteristics of the resin are changed through acylation reaction, so that the modified hydrogen type macroporous cationic resin shows better selectivity and affinity in the subsequent metal ion adsorption process; the introduced multi-sulfydryl functional group provides more adsorption sites for the resin, and the sites and metal ions can form a stable complex, so that the metal ions in a solution are effectively adsorbed and removed, and metal ion impurities in electronic-grade sulfuric acid are further reduced; the purity of the prepared electronic-grade sulfuric acid is 99.9999999%, the content of metal ions is only 5 ppt, and the electronic-grade sulfuric acid can meet the quality requirement of semiconductor-grade G5 of an ultra-large integrated circuit.

Description

Technical Field

[0001] The invention relates to the technical field of electronic grade sulfuric acid, in particular to a method for preparing electronic grade sulfuric acid. Background Art

[0002] Electronic grade sulfuric acid is an ultra-clean and high-purity reagent, mainly used for cleaning and etching silicon wafers. It can effectively remove impurity particles, inorganic residues and carbon deposits on silicon wafers. Its purity directly affects the yield of integrated circuits and is widely used in the assembly and processing of semiconductors and ultra-large-scale integrated circuits. The purity and cleanliness of electronic grade sulfuric acid have an important impact on the yield, electrical performance and reliability of electronic components.

[0003] Chinese patent CN113274750B: belongs to the field of chemical product preparation, and particularly relates to an electronic grade sulfuric acid preparation device and its preparation method. The device includes a pretreatment tank, which contains strong oxidants, including potassium permanganate and potassium dichromate, for oxidizing reducing impurities in industrial sulfuric acid raw materials; a distillation tower with an internal temperature of 185-195°C and a pressure of 1.45-2.23kPa, for removing sulfate impurities generated by oxidation reaction in the pretreatment tank to obtain high-purity sulfuric acid; an absorption treatment tower, in which an alkaline solution is provided, for absorbing and neutralizing the acidic waste gas generated in the distillation tower; and a microporous filter membrane is provided in the filter, which can filter out fine solid particle impurities in high-purity sulfuric acid.

[0004] Chinese patent CN114314525A: Provides a process for preparing electronic grade sulfuric acid by a gas absorption method, comprising the following steps: A) introducing pressurized liquid sulfur and preheated oxygen into a sulfur dioxide generator for oxidation to obtain SO2; B) transporting the SO2 and preheated O2 to a reactor, reacting under the action of a catalyst to obtain SO3; C) introducing SO3 into an absorption tower, using circulating oleum to absorb SO3, and the obtained high-concentration oleum enters a decomposition tower after leaving the absorption tower, and decomposition obtains pure SO3 and low-concentration oleum, and the low-concentration oleum returns to the absorption tower for absorbing SO3; D) reacting the pure SO3 obtained by decomposition with pure water to obtain electronic grade sulfuric acid.

[0005] Chinese patent CN116281877A: relates to the field of electronic grade sulfuric acid preparation, specifically to a method for preparing electronic grade sulfuric acid; the invention adopts distillation and impurity removal technology, ultrapure water absorption technology, distillation and light removal technology, and distillation and heavy removal technology.

[0006] The electronic-grade sulfuric acid prepared by the above patents and prior art has poor and unstable metal ions and particles, and cannot meet the G5 quality requirements of semiconductor grade for ultra-large integrated circuits. Summary of the invention

[0007] The present invention aims to solve the problem of residual metal ions in electronic-grade sulfuric acid in the prior art, and provides a method for preparing electronic-grade sulfuric acid, which greatly reduces the metal ion content of electronic-grade sulfuric acid and meets the semiconductor-grade G5 quality requirements of ultra-large integrated circuits.

[0008] To achieve the above object, the technical solution adopted by the present invention is:

[0009] A method for preparing electronic grade sulfuric acid, the operating steps are:

[0010] S1: Industrial-grade liquid sulfur trioxide is heated and gasified to obtain gaseous sulfur trioxide;

[0011] S2: passing gaseous sulfur trioxide through a demister and a dehumidifier to remove impurities and particles in the gas to obtain high-purity sulfur trioxide gas;

[0012] S3: High-purity sulfur trioxide gas and circulating electronic-grade sulfuric acid are absorbed in an absorption device to obtain electronic-grade sulfuric acid crude product;

[0013] S4: The electronic grade sulfuric acid crude product is passed through a degassing device to remove the reducing substances; then a modified hydrogen-type macroporous cationic resin is added to adsorb and exchange metal ions, thereby further reducing the metal ion impurities in the electronic grade sulfuric acid;

[0014] S5: The crude electronic grade sulfuric acid is filtered through multiple groups of high-efficiency membrane combinations to remove particulate matter in the electronic grade sulfuric acid to obtain electronic grade sulfuric acid.

[0015] In the above scheme of the method, the content of industrial-grade liquid sulfur trioxide is 99.9%.

[0016] In the above scheme of the method, the gasification pressure is -10 to 10 kPa, and the operating temperature is 35 to 50°C.

[0017] In the above scheme of the present method, the absorption device is composed of three absorption towers connected in series, and each absorption tower is equipped with a cooler to remove the reaction heat.

[0018] In the above scheme of the present method, the absorption temperature is 60-90°C and the pressure is -10 to 10 kPa.

[0019] In the above scheme of the present method, the preparation method of the modified hydrogen-type macroporous cationic resin is:

[0020] K1: Acylation reaction:

[0021] According to weight, 100-150 parts of dry sodium macroporous cationic resin are immersed in 1000-2000 parts of ethylene dichloride; then 5-10 parts of 4,4'-diacyl chloride diphenyl ether and 2-5 parts of zinc chloride are added, and the mixture is stirred and immersed for 10-15 hours at a reaction condition of -20-0°C, and then filtered and dried to obtain a precursor 1;

[0022] K2: Plasma treatment:

[0023] The precursor is introduced into a plasma chamber, the pressure is increased to 70-90 mTorr, and the precursor is exposed to the plasma gas for treatment at a power of 150-250 W for 20-60 minutes. After the treatment is completed, the resin is taken out to obtain a precursor 2;

[0024] K3: Place it in an ion exchange column and slowly pass a 0.5-1.5M hydrochloric acid solution at a flow rate of 1-3 times the bed height per hour. This operation ensures that the hydrogen ions are fully exchanged with the sodium ions on the resin; use deionized water to thoroughly rinse the resin until the pH value of the washing water is 6-7, and test the conductivity of the washing water to ensure that there are no residual chloride ions and sodium ions to obtain a modified hydrogen-type macroporous cationic resin.

[0025] In the above scheme of the method, the plasma gas is dithiosuccinic acid vapor: argon gas in a volume ratio of 1:0.5-1.

[0026] In the above scheme of the method, the plasma gas flow rate is 20-45 ml / min.

[0027] Reaction mechanism:

[0028] In the acylation reaction, 4,4'-diacyl diphenyl ether chloride acts as an acylating agent to react with the benzene ring on the dry sodium macroporous cationic resin; this reaction is usually carried out through the Friedel-Crafts acylation reaction mechanism, in which the acyl chloride portion of the 4,4'-diacyl diphenyl ether chloride is attacked by a catalyst (such as AlCl3) to form an acyl cation; this cation then attacks the benzene ring of styrene, replacing the hydrogen atom and forming an acylated polystyrene resin; in this process, the diphenyl ether portion acts as a passivating agent, helping to stabilize the sulfonic acid group and prevent it from falling off during the reaction.

[0029] During the plasma treatment process, the precursor (acylated resin) is exposed to a plasma environment, generating high-energy particle flows; these particle flows can introduce dithiol functional groups onto the benzene rings of the resin; the high-energy electrons and ions in the plasma bombard the resin surface, breaking the original chemical bonds and introducing new functional groups (such as SH-); these newly introduced thiol (-SH) functional groups increase the chemical active points of the resin, providing more possibilities for subsequent metal ion adsorption.

[0030] Technical effect:

[0031] 1. Enhanced stability: The diphenyl ether structure introduced through the acylation reaction makes the sulfonic acid group in the polystyrene resin more stable, reduces the shedding during subsequent use or treatment, and improves the service life and efficiency of the resin;

[0032] 2. Improve chemical properties: The acylation reaction changes the surface properties of the resin, making it show better selectivity and affinity in the subsequent metal ion adsorption process, thereby improving the efficiency of removing metal impurities;

[0033] 3. Increase adsorption sites: The introduced polythiol functional groups provide more adsorption sites for the resin, which can form stable complexes with metal ions, thereby effectively adsorbing and removing metal ions in the solution;

[0034] 4. Improve removal efficiency: Since the polythiol functional groups form complexes with metal ions, this mode of action is stronger than simple ion exchange, and can capture and remove metal ions at lower concentrations, thereby improving removal efficiency and purification depth;

[0035] 5. The electronic grade sulfuric acid prepared by the present invention has a purity of 99.99999999% and a metal ion content of only 5ppt, which can meet the G5 quality requirements of semiconductor grade for ultra-large integrated circuits. DETAILED DESCRIPTION

[0036] In order to have a clearer understanding of the technical features, purposes and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be construed as limiting the applicable scope of the present invention.

[0037] Among them, the purity and metal ion concentration of electronic-grade sulfuric acid are tested in accordance with the electronic-grade sulfuric acid standard GB / T41881-2022.

[0038] Example 1

[0039] A method for preparing electronic grade sulfuric acid, the operating steps are:

[0040] S1: Industrial-grade liquid sulfur trioxide is heated and gasified to obtain gaseous sulfur trioxide;

[0041] S2: passing gaseous sulfur trioxide through a demister and a dehumidifier to remove impurities and particles in the gas to obtain high-purity sulfur trioxide gas;

[0042] S3: High-purity sulfur trioxide gas and circulating electronic-grade sulfuric acid are absorbed in an absorption device to obtain electronic-grade sulfuric acid crude product;

[0043] S4: The electronic grade sulfuric acid crude product is passed through a degassing device to remove the reducing substances; then a modified hydrogen-type macroporous cationic resin is added to adsorb and exchange metal ions to further reduce the metal ion impurities in the electronic grade sulfuric acid;

[0044] S5: The crude electronic grade sulfuric acid is filtered through multiple groups of high-efficiency membrane combinations to remove particulate matter in the electronic grade sulfuric acid to obtain electronic grade sulfuric acid.

[0045] The industrial-grade liquid sulfur trioxide content is 99.9%.

[0046] The gasification pressure is -10 kPa and the operating temperature is 35°C.

[0047] The absorption device is composed of three absorption towers connected in series, and each absorption tower is equipped with a cooler to remove the reaction heat.

[0048] The absorption temperature is 70°C and the pressure is -0.005MPa.

[0049] The preparation method of the modified hydrogen-type macroporous cationic resin is as follows:

[0050] K1: Acylation reaction:

[0051] 100 g of dry sodium macroporous cationic resin was immersed in 1000 g of ethylene dichloride; 5 g of 4,4'-diacyl chloride diphenyl ether and 2 g of zinc chloride were added, and the mixture was stirred and immersed for 10 hours at -20°C, and then filtered and dried to obtain precursor 1;

[0052] K2: Plasma treatment:

[0053] The precursor was introduced into the plasma chamber, the pressure was increased to 70 mTorr, and the precursor was exposed to the plasma gas for treatment at a power of 150 W for 20 minutes. After the treatment was completed, the resin was taken out to obtain the precursor 2;

[0054] K3: Place the resin in an ion exchange column and slowly pass a 0.5M hydrochloric acid solution at a flow rate of 1 times the bed height per hour. This operation ensures that the hydrogen ions are fully exchanged with the sodium ions on the resin. Rinse the resin thoroughly with deionized water until the pH value of the washing water is 6. Test the conductivity of the washing water to ensure that there are no residual chloride ions and sodium ions, and obtain a modified hydrogen-type macroporous cationic resin.

[0055] The plasma gas is dithiosulfate vapor: argon gas in a volume ratio of 1:0.5.

[0056] The plasma gas flow rate is 20 ml / min.

[0057] The cation exchange resin is a 732 type strongly acidic cation exchange resin.

[0058] Example 2

[0059] A method for preparing electronic grade sulfuric acid, the operating steps are:

[0060] S1: Industrial-grade liquid sulfur trioxide is heated and gasified to obtain gaseous sulfur trioxide;

[0061] S2: passing gaseous sulfur trioxide through a demister and a dehumidifier to remove impurities and particles in the gas to obtain high-purity sulfur trioxide gas;

[0062] S3: High-purity sulfur trioxide gas and circulating electronic-grade sulfuric acid are absorbed in an absorption device to obtain electronic-grade sulfuric acid crude product;

[0063] S4: The electronic grade sulfuric acid crude product is passed through a degassing device to remove the reducing substances; then a modified hydrogen-type macroporous cationic resin is added to adsorb and exchange metal ions, thereby further reducing the metal ion impurities in the electronic grade sulfuric acid;

[0064] S5: The crude electronic grade sulfuric acid is filtered through multiple groups of high-efficiency membrane combinations to remove particulate matter in the electronic grade sulfuric acid to obtain electronic grade sulfuric acid.

[0065] The industrial-grade liquid sulfur trioxide content is 99.9%.

[0066] The gasification pressure is -5 kPa and the operating temperature is 40°C.

[0067] The absorption device is composed of three absorption towers connected in series, and each absorption tower is equipped with a cooler to remove the reaction heat.

[0068] The absorption temperature is 65°C and the pressure is -0.002MPa.

[0069] The preparation method of the modified hydrogen-type macroporous cationic resin is as follows:

[0070] K1: Acylation reaction:

[0071] 110 g of dry sodium macroporous cationic resin was immersed in 1400 g of ethylene dichloride; 6 g of 4,4'-diacyl chloride diphenyl ether and 3 g of zinc chloride were added, and the mixture was stirred and immersed for 12 hours at -15°C, and then filtered and dried to obtain a precursor 1;

[0072] K2: Plasma treatment:

[0073] The precursor was introduced into the plasma chamber, the pressure was increased to 75 mTorr, and the precursor was exposed to the plasma gas for treatment at a power of 180 W for 30 minutes. After the treatment was completed, the resin was taken out to obtain the precursor 2;

[0074] K3: Place it in an ion exchange column and slowly pass a 0.8M hydrochloric acid solution at a flow rate of 2 times the bed height per hour. This operation ensures that the hydrogen ions are fully exchanged with the sodium ions on the resin; use deionized water to thoroughly rinse the resin until the pH value of the washing water is 6, and test the conductivity of the washing water to ensure that there are no residual chloride ions and sodium ions, thereby obtaining a modified hydrogen-type macroporous cationic resin.

[0075] The plasma gas is dithiosulfate vapor: argon gas in a volume ratio of 1:0.6.

[0076] The plasma gas flow rate is 25 ml / min.

[0077] The cation exchange resin is a 732 type strongly acidic cation exchange resin.

[0078] Example 3

[0079] A method for preparing electronic grade sulfuric acid, the operating steps are:

[0080] S1: Industrial-grade liquid sulfur trioxide is heated and gasified to obtain gaseous sulfur trioxide;

[0081] S2: passing gaseous sulfur trioxide through a demister and a dehumidifier to remove impurities and particles in the gas to obtain high-purity sulfur trioxide gas;

[0082] S3: High-purity sulfur trioxide gas and circulating electronic-grade sulfuric acid are absorbed in an absorption device to obtain electronic-grade sulfuric acid crude product;

[0083] S4: The electronic grade sulfuric acid crude product is passed through a degassing device to remove the reducing substances; then a modified hydrogen-type macroporous cationic resin is added to adsorb and exchange metal ions, thereby further reducing the metal ion impurities in the electronic grade sulfuric acid;

[0084] S5: The crude electronic grade sulfuric acid is filtered through multiple groups of high-efficiency membrane combinations to remove particulate matter in the electronic grade sulfuric acid to obtain electronic grade sulfuric acid.

[0085] The industrial-grade liquid sulfur trioxide content is 99.9%.

[0086] The gasification pressure is 5 kPa and the operating temperature is 46°C.

[0087] The absorption device is composed of three absorption towers connected in series, and each absorption tower is equipped with a cooler to remove the reaction heat.

[0088] The absorption temperature is 80°C and the pressure is 0.004MPa.

[0089] The preparation method of the modified hydrogen-type macroporous cationic resin is as follows:

[0090] K1: Acylation reaction:

[0091] 140 g of dry sodium macroporous cationic resin was immersed in 1800 g of ethylene dichloride; 8 g of 4,4'-diacyl chloride diphenyl ether and 4 g of zinc chloride were added, and the mixture was stirred and immersed at -5°C for 14 hours, and then filtered and dried to obtain a precursor 1;

[0092] K2: Plasma treatment:

[0093] The precursor was introduced into the plasma chamber, the pressure was increased to 85 mTorr, and the precursor was exposed to the plasma gas for treatment at a power of 230 W for 50 minutes. After the treatment was completed, the resin was taken out to obtain the precursor 2;

[0094] K3: Place the resin in an ion exchange column and slowly pass a 1.3M hydrochloric acid solution at a flow rate of 2 times the bed height per hour. This operation ensures that the hydrogen ions are fully exchanged with the sodium ions on the resin. Rinse the resin thoroughly with deionized water until the pH value of the washing water is 7. Test the conductivity of the washing water to ensure that there are no residual chloride ions and sodium ions, and obtain a modified hydrogen-type macroporous cationic resin.

[0095] The plasma gas is dithiosulfate vapor: argon gas in a volume ratio of 1:0.8.

[0096] The plasma gas flow rate is 40 ml / min.

[0097] The cation exchange resin is a D001 type strongly acidic cation exchange resin.

[0098] Example 4

[0099] A method for preparing electronic grade sulfuric acid, the operating steps are:

[0100] S1: Industrial-grade liquid sulfur trioxide is heated and gasified to obtain gaseous sulfur trioxide;

[0101] S2: passing gaseous sulfur trioxide through a demister and a dehumidifier to remove impurities and particles in the gas to obtain high-purity sulfur trioxide gas;

[0102] S3: High-purity sulfur trioxide gas and circulating electronic-grade sulfuric acid are absorbed in an absorption device to obtain electronic-grade sulfuric acid crude product;

[0103] S4: The electronic grade sulfuric acid crude product is passed through a degassing device to remove the reducing substances; then a modified hydrogen-type macroporous cationic resin is added to adsorb and exchange metal ions, thereby further reducing the metal ion impurities in the electronic grade sulfuric acid;

[0104] S5: The crude electronic grade sulfuric acid is filtered through multiple groups of high-efficiency membrane combinations to remove particulate matter in the electronic grade sulfuric acid to obtain electronic grade sulfuric acid.

[0105] The industrial-grade liquid sulfur trioxide content is 99.9%.

[0106] The gasification pressure is 10 kPa and the operating temperature is 48°C.

[0107] The absorption device is composed of three absorption towers connected in series, and each absorption tower is equipped with a cooler to remove the reaction heat.

[0108] The absorption temperature is 85°C and the pressure is 0.005MPa.

[0109] The preparation method of the modified hydrogen-type macroporous cationic resin is as follows:

[0110] K1: Acylation reaction:

[0111] 150 g of dry sodium macroporous cationic resin was immersed in 2000 g of ethylene dichloride; 10 g of 4,4'-diacyl chloride diphenyl ether and 5 g of zinc chloride were added, and the mixture was stirred and immersed for 15 hours at 0°C, and then filtered and dried to obtain precursor 1;

[0112] K2: Plasma treatment:

[0113] The precursor was introduced into the plasma chamber, the pressure was increased to 90 mTorr, and the precursor was exposed to the plasma gas for treatment at a power of 250 W for 60 minutes. After the treatment was completed, the resin was taken out to obtain the precursor 2;

[0114] K3: Place the resin in an ion exchange column and slowly pass a 1.5M hydrochloric acid solution at a flow rate of 3 times the bed height per hour. This operation ensures that the hydrogen ions are fully exchanged with the sodium ions on the resin. Rinse the resin thoroughly with deionized water until the pH value of the washing water is 7. Test the conductivity of the washing water to ensure that there are no residual chloride ions and sodium ions, and obtain a modified hydrogen-type macroporous cationic resin.

[0115] The plasma gas is dithiosulfate vapor: argon gas in a volume ratio of 1:1.

[0116] The plasma gas flow rate is 45 ml / min.

[0117] The cation exchange resin is a D001 type strongly acidic cation exchange resin.

[0118] Comparative Example 1

[0119] The cation exchange resin was not modified, and the other steps were the same as in Example 1.

[0120] Comparative Example 2

[0121] No plasma treatment was performed, and the rest was the same as in Example 1.

[0122] Comparative Example 3

[0123] The other steps were the same as those in Example 1 except that 4,4'-diacyl dichloride diphenyl ether was not added.

[0124] Purity of electronic grade sulfuric acid / % Metal ion concentration / ppt Example 1 99.9999991 10 Example 2 99.9999994 8 Example 3 99.9999997 6 Example 4 99.9999999 5 Comparative Example 1 85.34 58 Comparative Example 2 90.25 32 Comparative Example 3 92.17 26

[0125] Through the data analysis of the above embodiments and comparative examples, the purity of sulfuric acid of the present invention after being treated with modified hydrogen-type macroporous cationic resin is as high as 99.9999999%, and the metal ion concentration is only 5ppt, which can meet the semiconductor-grade G5 quality requirements of ultra-large integrated circuits.

[0126] The specific implementation methods described above provide a detailed description of the technical solutions and beneficial effects of the present invention. It should be understood that the above is only the most preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, supplements and equivalent substitutions made within the scope of the principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for preparing electronic grade sulfuric acid, the operating steps are: S1: Industrial-grade liquid sulfur trioxide is heated and gasified to obtain gaseous sulfur trioxide; S2: passing gaseous sulfur trioxide through a demister and a dehumidifier to remove impurities and particles in the gas to obtain high-purity sulfur trioxide gas; S3: High-purity sulfur trioxide gas and circulating electronic-grade sulfuric acid are absorbed in an absorption device to obtain electronic-grade sulfuric acid crude product; S4: The electronic grade sulfuric acid crude product is passed through a degassing device to remove the reducing substances; then a modified hydrogen-type macroporous cationic resin is added to adsorb and exchange metal ions, thereby further reducing the metal ion impurities in the electronic grade sulfuric acid; S5: The crude electronic grade sulfuric acid is filtered through multiple groups of high-efficiency membrane combinations to remove particulate matter in the electronic grade sulfuric acid to obtain electronic grade sulfuric acid.

2. A method for preparing electronic grade sulfuric acid according to claim 1, characterized in that: The industrial-grade liquid sulfur trioxide content is 99.9%.

3. A method for preparing electronic grade sulfuric acid according to claim 1, characterized in that: The gasification pressure is -10 to 10 kPa, and the operating temperature is 35 to 50°C.

4. A method for preparing electronic grade sulfuric acid according to claim 1, characterized in that: The absorption device is composed of three absorption towers connected in series, and each absorption tower is equipped with a cooler to remove the reaction heat.

5. A method for preparing electronic grade sulfuric acid according to claim 1, characterized in that: The absorption temperature is 60-90°C and the pressure is -10-10kPa.

6. A method for preparing electronic grade sulfuric acid according to claim 1, characterized in that: The preparation method of the modified hydrogen-type macroporous cationic resin is as follows: K1: Acylation reaction: According to weight, 100-150 parts of dry sodium macroporous cationic resin are immersed in 1000-2000 parts of ethylene dichloride, and then 5-10 parts of 4,4'-diacyl chloride diphenyl ether and 2-5 parts of zinc chloride are added, and the mixture is stirred and immersed for 10-15 hours at a reaction condition of -20-0°C, and then filtered and dried to obtain a precursor 1; K2: Plasma treatment: The precursor is introduced into a plasma chamber, the pressure is increased to 70-90 mTorr, and the precursor is exposed to the plasma gas for treatment at a power of 150-250 W for 20-60 minutes. After the treatment is completed, the resin is taken out to obtain a precursor 2; K3: Place it in an ion exchange column and slowly pass a 0.5-1.5M hydrochloric acid solution at a flow rate of 1-3 times the bed height per hour. This operation ensures that the hydrogen ions are fully exchanged with the sodium ions on the resin; use deionized water to thoroughly rinse the resin until the pH value of the washing water is 6-7, and test the conductivity of the washing water to ensure that there are no residual chloride ions and sodium ions to obtain a modified hydrogen-type macroporous cationic resin.

7. A method for preparing electronic grade sulfuric acid according to claim 6, characterized in that: The plasma gas is dithiosulfate vapor: argon gas, and the volume ratio is 1:0.5-1.

8. A method for preparing electronic grade sulfuric acid according to claim 6, characterized in that: The plasma gas flow rate is 20-45 ml / min.