Electronic-grade citric acid production process based on combination of extraction and ion exchange resin

Abstract

The invention relates to an electronic-grade citric acid production process based on combination of extraction and ion exchange resin, which comprises the following steps: adding an extraction agent into an industrial-grade citric acid solution with higher impurity content for pretreatment, adsorbing part of metal impurities in the citric acid solution, and performing two-phase separation after the extraction is completed, an organic extraction phase obtained through separation is regenerated and reused; the citric acid purified liquid obtained through separation passes through a three-stage purification resin column, the residual extracting agent, main metal impurities, residual gold impurities and anions are sequentially removed, and finally the electronic-grade citric acid solution is obtained. The process is high in production efficiency, simple in equipment and suitable for industrial popularization.

Description

Technical Field

[0001] The invention relates to the technical field of chemical industry, and in particular to a production process of electronic grade citric acid based on the combination of extraction and ion exchange resin. Background Art

[0002] As a key fine chemical raw material, electronic grade citric acid plays a vital role in modern industry, especially in the electronics manufacturing and semiconductor industries. Due to its unique chemical properties, high-purity citric acid is widely used in these fields in key processes such as cleaning, etching and polishing to ensure the surface quality and functionality of electronic components and semiconductor materials. High-purity citric acid can effectively remove impurities and metal ions, thereby avoiding the potential negative impact of these impurities on the performance of electronic products. Therefore, the purity of electronic grade citric acid is directly related to the quality and reliability of the final product, and is crucial to improving the performance of electronic and semiconductor products.

[0003] In the production process of electronic-grade citric acid, the removal of metal impurities is a key step to ensure the high purity of the product. Traditionally, this process mainly relies on physical and chemical methods such as precipitation and filtration. Although these methods are able to remove metal impurities to a certain extent, they have some significant limitations. First, the precipitation process often requires the use of a large amount of chemical reagents, which not only increases the processing cost, but also may produce a large amount of chemical waste, which has a negative impact on the environment. Secondly, the filtration process may be inefficient, especially for the removal of trace metal ions, which may result in insufficient product purity to meet the high standards required by the electronics manufacturing and semiconductor industries. In addition, these traditional methods often require multiple treatments to achieve the required purity level, further increasing production costs and time. Therefore, the development of more efficient, cost-effective and environmentally friendly metal removal technologies is crucial for the production of electronic-grade citric acid. Summary of the invention

[0004] In view of the problems of low citric acid purity, low production efficiency, high energy consumption, complex technical route, etc. in the prior art, the present invention provides a simple and efficient method for preparing an electronic grade citric acid solution.

[0005] To achieve the purpose of the present invention, the present invention adopts the following technical solutions: A production process of electronic grade citric acid based on extraction combined with ion exchange resin comprises the following steps: S1: Add industrial-grade solid citric acid and ultrapure water into a dissolution tank to prepare a citric acid stock solution of a certain concentration.

[0006] S2: Mix the extractant and the diluent according to a set ratio.

[0007] S3: Add citric acid stock solution and organic extractant in a certain proportion for extraction, set the temperature, stirring rate, and extraction times, and after the mixed solution is extracted, separate the water phase and the oil phase.

[0008] S4: regenerating the organic extractant obtained after separation in step S3 and retaining it for later use.

[0009] S5: injecting the purified citric acid solution 1 obtained after separation in step S3 into three-stage series resin columns, wherein the first-stage resin column is filled with a macroporous adsorption resin to remove the residual organic extractant in the purified citric acid solution 1 to obtain a purified citric acid solution 2; the second-stage resin column is filled with a strong acid cationic resin to remove the residual metal impurities in the purified citric acid solution 2 to obtain a purified citric acid solution 3; the third-stage resin column is filled with a strong acid and strong base mixed bed resin to remove the residual trace metal and anion impurities in the purified citric acid solution 3 to obtain a purified citric acid solution 4.

[0010] S6: titrating the purified citric acid solution 4 obtained in step S5, adding a certain amount of ultrapure water, and preparing an electronic grade citric acid product with a mass concentration of 20%.

[0011] Further, the mass concentration of the citric acid stock solution in step S1 is not higher than 45%. The citric acid stock solution contains anionic impurities and cationic impurities, wherein the anionic impurities include at least one of nitrate, sulfate, phosphate, and chloride, and the content of each anionic impurity is between 200ppb and 1000ppb; the cationic impurities include Zn, Cu, Ni, Co, Fe, Ca, K, Mg, Na, Li, etc., and the content of each cationic impurity is between 10ppb and 4000ppb, and the TOC content is 20-50ppm.

[0012] Furthermore, in step S2, the extracting agent is D2EHPA and LIX84-I, and the diluent is kerosene.

[0013] Furthermore, in step S3, the extraction temperature is 20-50° C., and the stirring speed is 50-200 rpm. If the temperature is too high or the stirring speed is too fast, emulsification may occur easily.

[0014] Furthermore, the regeneration method of the extractant in step S4 is to add 0.5-4 times the volume of 2-3 mol / L sulfuric acid solution to the organic extractant obtained after separation in S3, stir for 5-30 minutes for stripping, and repeat washing multiple times.

[0015] Furthermore, in step S5, the resin filled in the resin column 1 is selected from any one of NKA-9, NKA-Ⅱ, D4020, D4006, H103, D101B, and D3520.

[0016] Furthermore, the resin used in the resin column 2 in step S5 is a strongly acidic cationic resin, selected from any one of C100E, UCW3700, ZGC107, 001x10H, HZ-016, D001AM, and D001MB.

[0017] Furthermore, the resin used in the resin column 3 in step S5 is a mixed bed resin selected from any one of C100EDL, A600MB, ZGER8420, ZGA307MB, PG-18, MB15, and 4200CL.

[0018] The present invention provides an electronic grade citric acid production process based on extraction combined with ion exchange resin, which has the following beneficial effects: (1) The present invention effectively improves the pretreatment efficiency of citric acid stock solution by the extraction method. By adjusting the type and concentration of the solvent, the selective removal of specific metal ions can be achieved, thereby ensuring the high purity of citric acid. The extraction agent can be regenerated and reused to greatly reduce the generation of chemical waste, significantly reduce production costs, and achieve cost-effectiveness.

[0019] (2) In the present invention, the specific metal impurities in citric acid are effectively removed by the high selectivity of the ion exchange resin, thereby ensuring the high purity of the product. The ion exchange resin method is simple to operate and easy to realize automatic control, thereby improving production efficiency and reducing operating errors. In addition, the ion exchange resin can be regenerated to restore its adsorption capacity after being used for a period of time, thereby extending its service life and further reducing costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0021] Embodiment 1: S1: Add industrial-grade solid citric acid and ultrapure water into a reactor to dissolve and prepare a citric acid stock solution with a mass concentration of 22%.

[0022] S2: Prepare a 30% Lix84-I / kerosene extraction system in a blender.

[0023] S3: Add 22% citric acid stock solution and 30% Lix84-I / kerosene in a volume ratio of 1:2 into the constant temperature stirrer 2, set the temperature to 40°C, the stirring rate to 100 rpm, and mix thoroughly for 10 minutes. After the mixed solution is extracted, pour it into a separatory funnel to separate the aqueous phase and the oil phase, and repeat the extraction twice.

[0024] S4: Add 2 mol / L sulfuric acid solution to the organic extractant obtained after separation in S3 at a ratio of 1:1, stir for 10 minutes for back extraction, repeat the washing twice, and keep the regenerated extractant for later use.

[0025] S5: The purified citric acid solution 1 obtained after separation in S3 is injected into three-stage series resin columns, wherein the first-stage resin column uses macroporous adsorption resin NKA-Ⅱ to remove residual organic extractant in the citric acid solution to obtain purified citric acid solution 2; the second-stage resin column uses strong acid cationic resin ZGC107 to remove residual metal ion impurities in the citric acid solution to obtain purified citric acid solution 3; the tertiary resin column uses strong acid and strong base mixed bed resin C100EDL to remove residual trace metal ions and anion impurities in the citric acid solution to obtain electronic grade citric acid solution.

[0026] S6: The obtained low-metal citric acid solution is titrated and ultrapure water is added to prepare an electronic grade citric acid product with a mass concentration of 20%.

[0027]

[0028] Embodiment 2: S1: Add industrial-grade solid citric acid and ultrapure water into a reactor to dissolve and prepare a citric acid stock solution with a mass concentration of 37%.

[0029] S2: Prepare a 30% D2EHPA / kerosene extraction system in a blender.

[0030] S3: Add 37% citric acid stock solution and 30% D2EHPA / kerosene in a volume ratio of 1:1 into the thermostatic stirrer 2, set the temperature to 40°C, stir at a rate of 150 rpm, mix thoroughly for 20 min, and after the mixed solution is extracted, pour it into a separatory funnel to separate the aqueous phase and the oil phase, and repeat the extraction twice.

[0031] S4: Add 2 mol / L sulfuric acid solution to the organic extractant obtained after separation in S3 at a ratio of 1:1, stir for 15 minutes for back extraction, repeat the washing twice, and keep the regenerated extractant for later use.

[0032] S5: The purified citric acid solution 1 obtained after separation in S3 is injected into three-stage series resin columns, wherein the first-stage resin column uses macroporous adsorption resin D4006 to remove the residual organic extractant in the citric acid solution to obtain purified citric acid solution 2; the second-stage resin column uses strong acid cationic resin UCW3700 to remove the residual metal impurities in the citric acid solution to obtain purified citric acid solution 3; the tertiary resin column uses strong acid and strong base mixed bed resin MB15 to remove the residual trace metal and anion impurities in the citric acid solution to obtain an electronic grade citric acid solution.

[0033] S6: The obtained low-metal citric acid solution is titrated and ultrapure water is added to prepare an electronic grade citric acid product with a mass concentration of 35%.

[0034]

[0035] Embodiment 3: S1: Add industrial-grade solid citric acid and ultrapure water into a reactor to dissolve and prepare a citric acid stock solution with a mass concentration of 42%.

[0036] S2: Prepare an extraction system of 15% Lix84-I + 15% D2EHPA / kerosene in a blender.

[0037] S3: Add 42% citric acid stock solution and 15% Lix84-I + 15% D2EHPA / kerosene in a volume ratio of 2:1 into the constant temperature stirrer 2, set the temperature to 45 ° C, the stirring rate to 200 rpm, and mix thoroughly for 20 minutes. After the mixed solution is extracted, pour it into a separatory funnel to separate the aqueous phase and the oil phase, and repeat the extraction twice.

[0038] S4: Add 2 mol / L sulfuric acid solution to the organic extractant obtained after separation in S3 at a ratio of 1:1, stir for 20 minutes for back extraction, repeat the washing twice, and keep the regenerated extractant for later use.

[0039] S5: The purified citric acid solution 1 obtained after separation in S3 is injected into three-stage series resin columns, wherein the first-stage resin column uses macroporous adsorption resin D3520 to remove the residual organic extractant in the citric acid solution to obtain purified citric acid solution 2; the second-stage resin column uses strong acid cationic resin C100E to remove the residual metal impurities in the citric acid solution to obtain purified citric acid solution 3; the third-stage resin column uses strong acid and strong base mixed bed resin ZGA307MB to remove the residual trace metal and anion impurities in the citric acid solution to obtain an electronic grade citric acid solution.

[0040] S6: The obtained low-metal citric acid solution is titrated and ultrapure water is added to prepare an electronic grade citric acid product with a mass concentration of 40%.

[0041] .

Claims

1. A production process of electronic grade citric acid based on extraction combined with ion exchange resin, comprising the following steps: S1: Add industrial-grade solid citric acid and ultrapure water into a dissolution tank to prepare a citric acid stock solution of a certain concentration; S2: Mixing the extractant and the diluent according to a set ratio; S3: adding citric acid stock solution and organic extractant in a certain proportion for extraction, setting the temperature, stirring rate, and extraction times, and after the mixed solution is extracted, separating the aqueous phase and the oil phase to obtain a purified citric acid solution 1; S4: injecting the purified citric acid solution 1 obtained after separation in step S3 into three-stage series-connected resin columns, wherein the first-stage resin column is filled with a macroporous adsorption resin to remove the residual organic extractant in the purified citric acid solution 1 to obtain a purified citric acid solution 2; and the second-stage resin column is filled with a strong acid cationic resin to remove the residual metal impurities in the purified citric acid solution 2 to obtain a purified citric acid solution 3; The tertiary resin column is filled with a strong acid and strong base mixed bed resin to remove the trace metal and anion impurities remaining in the citric acid purified solution 3 to obtain a citric acid purified solution 4; S5: titrating the purified citric acid solution 4 obtained in step S4, adding a certain amount of ultrapure water, and preparing an electronic grade citric acid solution product.

2. The process for producing electronic grade citric acid based on extraction and ion exchange resin as claimed in claim 1, characterized in that: The mass concentration of the citric acid stock solution in step S1 is not higher than 45%; the citric acid stock solution contains anionic impurities and cationic impurities, wherein the anionic impurities include at least one of nitrate, sulfate, phosphate, and chloride, and the content of each anionic impurity is between 200ppb and 1000ppb; the cationic impurities include Zn, Cu, Ni, Co, Fe, Ca, K, Mg, Na, Li, etc., and the content of each cationic impurity is between 10ppb and 4000ppb, and the TOC content is 20-50ppm.

3. The production process of electronic grade citric acid based on extraction and ion exchange resin as claimed in claim 1, characterized in that: The organic extractant in step S2 contains an extractant and a diluent, wherein the extractant is D2EHPA and LIX84-I, and the diluent is kerosene.

4. The process for producing electronic grade citric acid based on extraction and ion exchange resin as claimed in claim 1, characterized in that: In step S3, the extraction temperature is 20-50° C., and the stirring speed is 50-200 rpm.

5. The production process of electronic grade citric acid based on extraction and ion exchange resin as claimed in claim 1, characterized in that: The oil phase separated in step S3 is regenerated and stored for later use; The regeneration method of the extractant is to add 0.5-4 times the volume of 2-3 mol / L sulfuric acid solution to the organic extractant obtained after separation, stir for 5-30 minutes for back extraction, and repeat washing for multiple times.

6. The process for producing electronic grade citric acid based on extraction combined with ion exchange resin according to claim 1, characterized in that: In the step S4, the macroporous adsorption resin filled in the primary resin column is selected from any one of NKA-9, NKA-Ⅱ, D4020, D4006, H103, D101B, and D3520.

7. The process for producing electronic grade citric acid based on extraction combined with ion exchange resin as claimed in claim 1, characterized in that: The resin used in the secondary resin column in step S4 is a strongly acidic cationic resin selected from any one of C100E, UCW3700, ZGC107, 001x10H, HZ-016, D001AM, and D001MB.

8. The process for producing electronic grade citric acid based on extraction combined with ion exchange resin as claimed in claim 1, characterized in that: The resin used in the tertiary resin column in step S4 is a mixed bed resin selected from any one of C100EDL, A600MB, ZGER8420, ZGA307MB, PG-18, MB15, and 4200CL.

9. The process for producing electronic grade citric acid based on extraction combined with ion exchange resin according to claim 1, characterized in that: The concentration of the electronic grade citric acid solution in step S4 is 10-30%.

10. An electronic grade citric acid, characterized in that: The electronic-grade citric acid prepared by the production process according to any one of claims 1 to 9, wherein the content of each anion in the electronic-grade citric acid is less than 10 ppb, more preferably less than 8 ppb, more preferably less than 6 ppb, and more preferably less than 5 ppb; the anion comprises at least one of nitrate, sulfate, phosphate, and chloride; The content of each anion in the electronic grade citric acid is less than 10 ppb, more preferably less than 8 ppb, more preferably less than 5 ppb, and more preferably less than 1 ppb; The cationic impurities include any one or more combinations of Zn, Cu, Ni, Co, Fe, Ca, K, Mg, Na, and Li.

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