CN-121974303-A - Preparation process for recycling electronic grade sulfuric acid from waste sulfuric acid

Abstract

The application relates to a preparation process for recycling electronic grade sulfuric acid from waste sulfuric acid, which comprises the following steps of S1, pretreatment, S2, membrane filtration, S3, ion exchange, S4, reduced pressure distillation, S5, sub-boiling distillation, wherein the waste sulfuric acid is subjected to precipitation and filtration to obtain pre-purified sulfuric acid, the pre-purified sulfuric acid obtained in the step S1 is pumped into a membrane filtration system and filtered to obtain clear sulfuric acid filtrate, the clear sulfuric acid filtrate obtained in the step S2 is subjected to ion exchange through an ion exchange column filled with a composite ion exchange material to collect effluent, and the effluent obtained in the step S3 is subjected to reduced pressure distillation to obtain the pre-purified sulfuric acid, and the sub-boiling distillation, S5, the pre-purified sulfuric acid obtained in the step S4 is subjected to sub-boiling distillation to obtain the electronic grade sulfuric acid. The content of various metals in the electronic grade sulfuric acid recovered by the process is lower than 30ppb.

Inventors

• ZHAO XIANHUA
• ZHANG LEHUA
• ZHU LINGHUI
• YAO HAN
• ZHENG YIHONG
• ZHANG WENZHUO
• Zhu Xiekang

Assignees

• 江苏电科环保有限公司
• 华东理工大学

Dates

Publication Date

20260505

Application Date

20260127

Claims (10)

1. 1. The preparation process for recycling the electronic grade sulfuric acid from the waste sulfuric acid is characterized by comprising the following steps of: S1, pretreatment, namely precipitating and filtering waste sulfuric acid to obtain pretreated waste sulfuric acid; s2, membrane filtration, namely pumping the pretreated waste sulfuric acid in the step S1 into a membrane filtration system, and filtering to obtain clarified sulfuric acid filtrate; S3, ion exchange, namely, passing the clarified sulfuric acid filtrate obtained in the step S2 through an ion exchange column filled with a composite ion exchange material, and collecting effluent liquid; S4, performing reduced pressure distillation, namely performing reduced pressure distillation on the effluent liquid obtained in the step S3 to obtain pre-purified sulfuric acid; And S5, sub-boiling distillation, namely sub-boiling distillation of the prepurified sulfuric acid obtained in the step S4 to obtain electronic grade sulfuric acid.
2. 2. The process for preparing electronic grade sulfuric acid from waste sulfuric acid according to claim 1, wherein in the step S3, the preparation raw materials of the composite ion exchange material comprise 64-76 parts by weight of strongly acidic styrene cation exchange resin, 20-30 parts by weight of polyaminophosphonic acid group chelating resin and 4-6 parts by weight of SiO 2 @ PVDF core-shell structure nanoparticles.
3. 3. The process for preparing the electronic grade sulfuric acid recovered from the waste sulfuric acid according to claim 2, wherein the mass ratio of the strongly acidic styrene cation exchange resin, the polyaminophosphonic acid group chelate resin and the SiO 2 @PVDF core-shell structured nano particles in the preparation raw materials of the composite ion exchange material is (32-38): 10-15): 2-3.
4. 4. The process for preparing the electronic grade sulfuric acid recovered from the waste sulfuric acid according to claim 2, wherein the mass ratio of the polyaminophosphonic acid group chelating resin to the SiO 2 @PVDF core-shell structured nano particles in the preparation raw material of the composite ion exchange material is (4-6.5): 1.
5. 5. The process for producing electronic grade sulfuric acid from waste sulfuric acid according to claim 2, wherein the process for producing polyaminophosphonic acid group chelating resin in the raw material for producing the composite ion exchange material comprises the steps of: a1, swelling the styrene-based chlorine ball macroporous resin, carrying out reflux reaction for 12-20h, and cleaning to obtain polyamino resin; a2, mixing the polyamino resin prepared in the step a1 with phosphorous acid, concentrated hydrochloric acid and deionized water, adding formaldehyde solution at 55-65 ℃, carrying out reflux reaction for 6-10h, carrying out reduced pressure distillation, and drying to obtain the polyamino phosphonic acid group chelating resin.
6. 6. The process for producing electronic grade sulfuric acid from waste sulfuric acid according to claim 5, wherein in said step a2, the mass ratio of the polyamino resin to the phosphorous acid is 1 (0.4-0.6).
7. 7. The process for producing electronic grade sulfuric acid from waste sulfuric acid according to claim 5, wherein in said step a2, the mass ratio of the polyamino resin to the concentrated hydrochloric acid is 1 (4-6).
8. 8. The process for preparing the electronic grade sulfuric acid recovered from the waste sulfuric acid according to claim 2, wherein the preparation method of the SiO 2 @PVDF core-shell structured nano particles in the composite ion exchange material comprises the following steps: b1, adding SiO 2 into toluene, carrying out ultrasonic treatment, adding MPS silane coupling agent and glacial acetic acid, heating to 80-90 ℃ under the protection of inert gas, reacting for 7-9h, centrifuging, filtering, washing and drying to obtain silanization modified SiO 2 powder; And b2, dispersing the silanization modified SiO 2 powder prepared in the step b1 in DMF, adding PVDF, stirring, freezing, vacuumizing, thawing, sealing, irradiating for 8-16h, centrifuging, washing and drying to obtain the SiO 2 @PVDF core-shell structure nanoparticle.
9. 9. The process for producing sulfuric acid from waste sulfuric acid according to claim 1, wherein the process for producing the composite ion exchange material comprises the steps of: c1, pre-treating strong-acid styrene cation exchange resin in sulfuric acid solution at 75-85 ℃ to obtain pre-treated strong-acid styrene cation exchange resin; c2. Adding polyamino phosphonic acid group chelate resin into the pretreated strong-acid styrene cation exchange resin obtained in the step c1, and stirring to obtain mixed resin; c3. Dispersing SiO 2 @PVDF core-shell structure nano particles in ethanol, carrying out ultrasonic treatment to obtain a suspension, adding the suspension into the mixed resin obtained in the step C2, heating to 50-70 ℃, stirring, reacting, filtering and drying to obtain the composite ion exchange material.
10. 10. Use of a process for the recovery of electronic grade sulfuric acid from spent sulfuric acid according to claims 1-9 for the recovery of spent sulfuric acid.

Description

Preparation process for recycling electronic grade sulfuric acid from waste sulfuric acid Technical Field The application relates to the technical field of waste sulfuric acid recovery, in particular to a preparation process for recovering electronic grade sulfuric acid from waste sulfuric acid. Background The electronic grade sulfuric acid is used as an ultra-clean high-purity reagent, has an irreplaceable function in the semiconductor industry, and is mainly used for the key processes of cleaning, photoetching, corrosion and the like of silicon wafers. With the rapid development of the semiconductor industry, the demand for electronic grade sulfuric acid increases year by year, but the high purity requirement makes the production cost high. Meanwhile, the generation of a large amount of waste sulfuric acid not only causes resource waste, but also brings serious environmental problems. At present, the recovery treatment of the waste sulfuric acid mainly adopts a distillation method, a membrane separation method and a chemical precipitation method. The distillation method separates impurities by heating and evaporating, but has high energy consumption and is easy to introduce secondary pollution, the membrane separation method separates impurities by utilizing a permselective membrane, but has high membrane material cost and is easy to block, and the chemical precipitation method precipitates impurities by adding chemical reagents, but is easy to introduce new pollutants and has unstable treatment effect. Therefore, development of an efficient and low-cost waste sulfuric acid recovery technology is an urgent need in the industry. Disclosure of Invention The application provides a preparation process for recycling electronic grade sulfuric acid from waste sulfuric acid, which can efficiently recycle high-purity electronic grade sulfuric acid from waste sulfuric acid at low cost, and avoids secondary pollution, environmental pollution and resource waste. In a first aspect of the application, the application provides a preparation process for recycling electronic grade sulfuric acid from waste sulfuric acid, which comprises the following steps of S1, pretreatment, S2, membrane filtration, S3, ion exchange, S4, reduced pressure distillation, S4, S5, and S5, wherein the waste sulfuric acid is precipitated and filtered to obtain pretreated waste sulfuric acid, the pretreated waste sulfuric acid in the step S1 is pumped into a membrane filtration system and filtered to obtain clarified sulfuric acid filtrate, the clarified sulfuric acid filtrate obtained in the step S2 is subjected to ion exchange through an ion exchange column filled with a composite ion exchange material, and effluent is collected, and the effluent obtained in the step S3 is subjected to reduced pressure distillation to obtain prepurified sulfuric acid, and the prepurified sulfuric acid obtained in the step S4 is subjected to sub-boiling distillation to obtain electronic grade sulfuric acid. Optionally, in the step S3, the preparation raw materials of the composite ion exchange material include 64-76 parts by weight of strong acid styrene cation exchange resin, 20-30 parts by weight of polyaminophosphonic acid group chelating resin and 4-6 parts by weight of SiO 2 @pvdf core-shell structure nanoparticles. By adopting the technical scheme, the application provides a preparation process for recycling electronic grade sulfuric acid from waste sulfuric acid, and the content of various metals in the electronic grade sulfuric acid obtained by treatment and recycling of the process is lower than 30ppb. The strong acid styrene cation exchange resin is used as a main adsorption phase, does not swell and degrade in strong sulfuric acid, the sulfonic group rapidly exchanges a large amount of metal ions to avoid H + competitive adsorption, the polyamino phosphonic acid resin can carry out deep and selective chelating capture on trace transition metal ions containing Fe, cu, ni, zn and other metal ions by virtue of a polydentate coordination structure, and the SiO 2 @PVDF core-shell nano particles utilize a high specific surface area inner core under the protection of an acid-resistant shell, so that tiny colloid particles, metal hydrolytic polymers and other nano impurities in waste acid are effectively adsorbed and intercepted, and the resin pores are prevented from being blocked or the exchange column is prevented from being penetrated. The three are matched together to stably reduce the content of various metal ions in the electronic grade sulfuric acid to below 30ppb. Alternatively, the strongly acidic styrenic cation exchange resin is a sulfonic acid type strongly acidic cation exchange resin. Optionally, in the preparation raw materials of the composite ion exchange material, the mass ratio of the strongly acidic styrene cation exchange resin to the polyamino phosphonic acid chelate resin to the SiO 2 @PVDF core-shell structure nanoparticle is (32-38)