Method for measuring content of sulfate ions in organic solvent

Abstract

The invention provides a method for determining the content of sulfate ions in an organic solvent. Accurate determination of the content of SO4 < 2-> in the organic solvent is realized by adopting a loaded organic solvent back extraction method. According to the determination method, the loaded organic solvent is subjected to back extraction to form phosphoric acid through the processes of back extraction, analysis and the like, the content of SO4 < 2-> in the phosphoric acid is determined by ICP, and the content of SO4 < 2-> in the organic solvent is calculated according to the content of SO4 < 2-> in the phosphoric acid, so that the interference of the organic solvent on the determination is avoided, and the accurate determination of the content of SO4 < 2-> in the organic solvent is ensured. The correlation between the detection result and the content of SO4 < 2-> in the product acid is high, and the purpose of accurately controlling production is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of detection methods, and more specifically, to a method for detecting sulfate ions (SO4 2- ) content determination method. Background Art

[0002] Solvent extraction is the mainstream method for producing purified phosphoric acid, with the characteristics of large production capacity, low energy consumption and low pollution. Methyl isobutyl ketone is a commonly used organic solvent for producing purified phosphoric acid by solvent extraction. In order to achieve precise control in the production of purified wet-process phosphoric acid, it is necessary to control the SO4 2- The content was measured.

[0003] At present, there is no unified detection standard for the determination of impurities in methyl isobutyl ketone. In actual detection, ICP (inductively coupled plasma emission spectroscopy) is generally used for determination. Determination of SO4 in methyl isobutyl ketone by ICP 2- It was found that the special properties of organic solvents interfered with ICP, resulting in ICP being unable to accurately determine the SO4 in the loaded organic solvent. 2- The content of SO4 in the product acid is often different from the test results. 2- The correlation of content is poor, the error is large, and it is impossible to accurately guide production regulation. Summary of the invention

[0004] In view of this, the purpose of the present invention is to provide a method for determining the sulfate ion content in an organic solvent, which adopts a loaded organic solvent back extraction method to achieve SO4 2- Accurate determination of content; This determination method uses the process of back extraction and analysis to back extract the loaded organic solvent into phosphoric acid, and uses ICP to determine the SO4 in phosphoric acid 2- Content, through SO4 in phosphoric acid 2- The content of SO4 in organic solvents is calculated 2- content, avoiding the interference of organic solvents on the determination, so as to ensure that SO4 2- Accurate determination of content, test results and SO4 in product acid 2- The content is highly correlated, achieving the purpose of precise control of production.

[0005] The present invention provides a method for determining the content of sulfate ions in an organic solvent, comprising the following steps:

[0006] a) mixing the loaded organic solvent to be tested with the desalted water, and then standing and separating them to obtain stripped phosphoric acid and an empty organic solvent respectively;

[0007] b) mixing the stripped phosphoric acid obtained in step a) with activated carbon, and filtering and separating the mixture to obtain resolved phosphoric acid;

[0008] c) mixing the resolved phosphoric acid obtained in step b) with the nitric acid solution, and then fixing the volume with water to obtain a sample solution;

[0009] d) Using ICP to measure the SO4 of the sample solution obtained in step c) 2- The emission spectrum intensity is consistent with the established SO4 2- Emission Spectrum Intensity-SO4 2- The mass concentration standard curve was compared to obtain the SO4 2- The mass concentration of sulfate ions in the organic solvent was calculated.

[0010] Preferably, the load organic solvent to be tested in step a) is methyl isobutyl ketone obtained in the wet purification phosphoric acid process, wherein the mass concentration of P2O5 is 10% to 20%, and SO4 2- The content is 0~1000mg / L.

[0011] Preferably, in step a), the volume ratio of the load organic solvent to be tested to the desalted water is (8-15):1.

[0012] Preferably, the mixing device in step a) is a high shear emulsifier, the mixing temperature is 40° C. to 60° C., the rotation speed is 10000 rpm to 15000 rpm, and the mixing time is 3 min to 8 min.

[0013] Preferably, the process of static separation in step a) is specifically as follows:

[0014] After the mixture is allowed to stand for 0.5 h to 1.5 h, it is phase-separated by a separatory funnel to obtain stripped phosphoric acid and an empty organic solvent, respectively.

[0015] Preferably, the amount of activated carbon added in step b) is 5% to 15% of the mass of the stripped phosphoric acid.

[0016] Preferably, the mixing temperature in step b) is 40° C. to 60° C., the rotation speed is 200 rpm to 400 rpm, and the time is 10 min to 15 min.

[0017] Preferably, in step c), the amount of the resolved phosphoric acid is 1 g, the amount of the nitric acid solution is 1 mL, and the volume is fixed to 250 mL with water.

[0018] Preferably, in step d), the SO4 2- Emission Spectrum Intensity-SO4 2- The specific process of establishing the mass concentration standard curve is as follows:

[0019] First, prepare a sulfate standard solution. Weigh 0.1480 g of anhydrous sodium sulfate dried to constant weight at 105°C to 110°C, dissolve it in water, transfer it into a 1000 mL volumetric flask, and dilute to scale. Use a pipette to transfer 0.00 mL, 2.00 mL, 4.00 mL, 6.00 mL, 8.00 mL, and 10.00 mL of the sulfate standard solution into a 100 mL volumetric flask, add 5.0 mL of nitric acid solution, dilute to scale with water, and shake well.

[0020] Then the above sulfate standard solutions are introduced into ICP in order from low concentration to high concentration, and the emission spectrum intensity is used as the vertical coordinate, and the SO4 2- The mass concentration of SO4 is plotted on the horizontal axis. 2- Emission Spectrum Intensity-SO4 2- Mass concentration standard curve.

[0021] Preferably, the calculation process in step d) is specifically as follows:

[0022] First use the formula Calculate the SO4 in the sample solution 2- The quality score of

[0023] Where: 1 is the SO4 in the sample solution 2- The quality score of

[0024] ρ1 is the SO4 in the sample solution found on the standard curve 2- The mass concentration of is in mg / L;

[0025] 0.025 is the dilution factor;

[0026] m1 is the mass of the sample solution, in g;

[0027] SO4 in the above sample solution 2- The mass fraction of SO4 in phosphoric acid is 2- The quality score of

[0028] Then use the formula Calculation of SO4 in organic solvents 2- The quality score of

[0029] Where: ω2 is SO4 in organic solvent 2- Quality score;

[0030] ω3 is SO4 in stripping phosphoric acid 2- Quality score;

[0031] m2 is the mass of organic solvent, in g;

[0032] m3 is the mass of stripped phosphoric acid, in g.

[0033] The invention provides a method for determining the sulfate ion content in an organic solvent, comprising the following steps: a) mixing a loaded organic solvent to be tested with desalted water, and performing static separation to obtain stripped phosphoric acid and an empty organic solvent respectively; b) mixing the stripped phosphoric acid obtained in step a) with activated carbon, and performing filtration separation to obtain resolved phosphoric acid; c) mixing the resolved phosphoric acid obtained in step b) with a nitric acid solution, and then performing constant volume with water to obtain a sample solution; d) using ICP to measure SO4 in the sample solution obtained in step c) 2- The emission spectrum intensity is consistent with the established SO4 2- Emission Spectrum Intensity-SO4 2- The mass concentration standard curve was compared to obtain the SO4 2- The mass concentration of sulfate ions in the organic solvent is calculated and the sulfate ion content in the organic solvent is obtained. Compared with the prior art, the method for determining the sulfate ion content in the organic solvent provided by the present invention adopts the method of stripping with a loaded organic solvent to achieve SO4 2- Accurate determination of content; This determination method uses the process of back extraction and analysis to back extract the loaded organic solvent into phosphoric acid, and uses ICP to determine the SO4 in phosphoric acid 2- Content, through SO4 in phosphoric acid 2- The content of SO4 in organic solvents is calculated 2- content, avoiding the interference of organic solvents on the determination, so as to ensure that SO4 2- Accurate determination of content, test results and SO4 in product acid 2- The content is highly correlated, achieving the purpose of precise control of production. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 This is the standard working curve drawn in Example 1 of the present invention. DETAILED DESCRIPTION

[0035] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The present invention provides a method for determining the content of sulfate ions in an organic solvent, comprising the following steps:

[0037] a) mixing the loaded organic solvent to be tested with the desalted water, and then standing and separating them to obtain stripped phosphoric acid and an empty organic solvent respectively;

[0038] b) mixing the stripped phosphoric acid obtained in step a) with activated carbon, and filtering and separating the mixture to obtain resolved phosphoric acid;

[0039] c) mixing the resolved phosphoric acid obtained in step b) with the nitric acid solution, and then fixing the volume with water to obtain a sample solution;

[0040] d) Using ICP to measure the SO4 of the sample solution obtained in step c) 2- The emission spectrum intensity is consistent with the established SO4 2- Emission Spectrum Intensity-SO4 2- The mass concentration standard curve was compared to obtain the SO4 2- The mass concentration of sulfate ions in the organic solvent was calculated.

[0041] Since MIBK is an organic solvent, there is no national standard or industry standard method to check any of its components. In actual production, SO4 2- It is a key indicator for purifying phosphoric acid, and is often measured directly by ICP method to measure SO4 in MIBK. 2- The results show that the ICP method can directly measure SO4 in MIBK. 2- There is a big gap between the theoretical value and the final product SO4 2- The correlation is poor and cannot guide production well. The present invention uses MIBK and desalted water to extract phosphoric acid and then measures the SO4 in phosphoric acid. 2- (This method has a national standard), according to the SO4 in phosphoric acid 2- SO4 in MIBK can be calculated 2- The SO4 measured by this method 2- It is closer to the theoretical value and SO4 2- The correlation is high and can better guide production regulation.

[0042] The invention firstly mixes the loaded organic solvent to be tested with the desalted water, and then performs static separation to obtain the stripped phosphoric acid and the empty organic solvent respectively.

[0043] In the present invention, the load organic solvent to be tested is preferably methyl isobutyl ketone obtained in the wet purification phosphoric acid process, wherein the mass concentration of P2O5 is preferably 10% to 20%, more preferably 12% to 15%, and SO4 2- The content is preferably 0 to 1000 mg / L.

[0044] In the present invention, the volume ratio of the load organic solvent to be tested to the desalted water is preferably (8-15):1, more preferably (10-12):1.

[0045] The present invention preferably adds desalted water to the load organic solvent to be tested for sufficient mixing and mass transfer; the mixing device in step a) is preferably a high shear emulsifier, the mixing temperature is preferably 40°C to 60°C, the rotation speed is preferably 10000rpm to 15000rpm, and the time is preferably 3min to 8min.

[0046] In the present invention, the static separation process is preferably specifically as follows:

[0047] The mixture is allowed to stand for 0.5 h to 1.5 h until it becomes stable, and then phase-separated by a separatory funnel to obtain stripped phosphoric acid and an empty organic solvent, respectively.

[0048] In the present invention, the stripped phosphoric acid is phosphoric acid extracted from an organic solvent with phosphorus and sulfur elements; the empty organic solvent is a solvent that does not carry phosphorus and sulfur elements after the loaded organic solvent is extracted, and can be recycled and reused in industrial production.

[0049] After obtaining the stripped phosphoric acid, the present invention mixes the stripped phosphoric acid obtained with activated carbon, and then performs filtration separation to obtain resolved phosphoric acid.

[0050] The present invention has no special limitation on the source of the activated carbon, and commercially available products known to those skilled in the art may be used.

[0051] In the present invention, the amount of activated carbon added is preferably 5% to 15% of the mass of the stripped phosphoric acid, and more preferably 10%.

[0052] In the present invention, the mixing temperature in step b) is preferably 40° C. to 60° C., the rotation speed is preferably 200 rpm to 400 rpm, and the time is preferably 10 min to 15 min; it can be implemented using a cantilever electric stirrer well known to those skilled in the art; and the methyl isobutyl ketone in the stripping phosphoric acid can be absorbed by the activated carbon.

[0053] In the present invention, the filtration separation preferably uses a circulating water vacuum pump and a Buchner funnel to obtain resolved phosphoric acid and simultaneously separate activated carbon containing a small amount of organic solvent; on this basis, the resolved phosphoric acid no longer contains methyl isobutyl ketone, and the activated carbon containing a small amount of organic solvent can be recycled and reused after harmless treatment.

[0054] After obtaining the analyzed phosphoric acid, the present invention mixes the obtained analyzed phosphoric acid with a nitric acid solution, and then fixes the volume with water to obtain a sample solution.

[0055] In the present invention, the amount of the analyzed phosphoric acid is preferably 1 g, accurate to 0.0001, and the amount of the nitric acid solution is preferably 1 mL, which is diluted to 250 mL with water.

[0056] After obtaining the sample solution, the present invention uses ICP to measure the SO4 2- The emission spectrum intensity is consistent with the established SO4 2- Emission Spectrum Intensity-SO4 2- The mass concentration standard curve was compared to obtain the SO4 2- The mass concentration of sulfate ions in the organic solvent was calculated.

[0057] The present invention has no special limitation on the technical solution of the ICP measurement, and the ICP measurement can be implemented by using the inductively coupled plasma emission spectrometry method well known to those skilled in the art.

[0058] In the present invention, the SO4 2- Emission Spectrum Intensity-SO4 2- The process of establishing the mass concentration standard curve is preferably as follows:

[0059] First, prepare the sulfate standard solution: weigh 0.1480g of anhydrous sodium sulfate dried to constant weight at 105℃~110℃, dissolve it in water, transfer it into a 1000mL volumetric flask, and dilute to scale; use a pipette to transfer 0.00mL, 2.00mL, 4.00mL, 6.00mL, 8.00mL, and 10.00mL of the sulfate standard solution into a 100mL volumetric flask, add 5.0mL of nitric acid solution, dilute to scale with water, and shake well;

[0060] Then draw the standard working curve: introduce the above sulfate standard solutions into ICP in order from low concentration to high concentration, with the emission spectrum intensity as the ordinate and the SO4 2- The mass concentration (mg / L) of SO4 is plotted as the horizontal axis. 2- Emission Spectrum Intensity-SO4 2- Mass concentration standard curve.

[0061] The present invention uses ICP to measure the sample solution to obtain the sample solution SO4 2- The emission spectrum intensity of the sample solution can be obtained based on the emission spectrum intensity of the sample solution SO4 2- The mass concentration (mg / L) of the sample solution SO4 2- quality score.

[0062] In the present invention, the calculation process is preferably specifically as follows:

[0063] First use the formula Calculate the SO4 in the sample solution 2- The quality score of

[0064] Where: ω1 is the SO4 in the sample solution 2- The quality score of

[0065] ρ1 is the SO4 in the sample solution found on the standard curve 2- The mass concentration of is in mg / L;

[0066] 0.025 is the dilution factor;

[0067] m1 is the mass of the sample solution, in g;

[0068] SO4 in the above sample solution 2- The mass fraction of SO4 in phosphoric acid is 2- The mass fraction of SO4 in phosphoric acid is analyzed by the present invention. 2- The mass fraction of SO4 in organic solvent can be calculated 2- quality score.

[0069] Then use the formula Calculation of SO4 in organic solvents 2- The quality score of

[0070] Where: ω2 is SO4 in organic solvent 2- Quality score;

[0071] 3 is the stripping of SO4 in phosphoric acid 2- Quality score;

[0072] 2 is the mass of organic solvent, in g;

[0073] 3 is the mass of stripped phosphoric acid, in g.

[0074] In addition, the present invention also directly measures SO4 2- The mass fraction of SO4 in the acid of this batch of products was used as a control experiment. 2- The content of SO4 in the organic solvent loaded in this batch can be calculated. 2- The theoretical content of the content is obtained by comparing the test results of this method with the test results of organic solvents directly using ICP. The error between the test results of this method and the theoretical content is smaller.

[0075] The present invention provides a method for determining the sulfate ion content in an organic solvent. The technical principle is as follows: using an organic solvent (methyl isobutyl ketone) during the back extraction process, phosphorus and sulfur elements are transferred to the water phase to obtain a SO4 2- Phosphoric acid, determination of SO4 in phosphoric acid by inductively coupled plasma emission spectrometry 2- The content of SO4 in the loaded solvent can be further calculated. 2-The present invention solves the interference of organic solvents on ICP detection by comparing the detection results of the two methods with the SO4 content in the product acid. 2- The results showed that this method is consistent with the SO4 content in the final product acid. 2- The correlation is higher.

[0076] The invention provides a method for determining the sulfate ion content in an organic solvent, comprising the following steps: a) mixing a loaded organic solvent to be tested with desalted water, and performing static separation to obtain stripped phosphoric acid and an empty organic solvent respectively; b) mixing the stripped phosphoric acid obtained in step a) with activated carbon, and performing filtration separation to obtain resolved phosphoric acid; c) mixing the resolved phosphoric acid obtained in step b) with a nitric acid solution, and then performing constant volume with water to obtain a sample solution; d) using ICP to measure SO4 in the sample solution obtained in step c) 2- The emission spectrum intensity is consistent with the established SO4 2- Emission Spectrum Intensity-SO4 2- The mass concentration standard curve was compared to obtain the SO4 2- The mass concentration of sulfate ions in the organic solvent is calculated and the sulfate ion content in the organic solvent is obtained. Compared with the prior art, the method for determining the sulfate ion content in the organic solvent provided by the present invention adopts the method of stripping with a loaded organic solvent to achieve SO4 2- Accurate determination of content; This determination method uses the process of back extraction and analysis to back extract the loaded organic solvent into phosphoric acid, and uses ICP to determine the SO4 in phosphoric acid 2- Content, through SO4 in phosphoric acid 2- The content of SO4 in organic solvents is calculated 2- content, avoiding the interference of organic solvents on the determination, so as to ensure that SO4 2- Accurate determination of content, test results and SO4 in product acid 2- The content is highly correlated, achieving the purpose of precise control of production.

[0077] In order to further illustrate the present invention, the following examples are used to describe in detail the method for determining the sulfate ion content in an organic solvent provided by the present invention. The loaded organic solvent in the following examples of the present invention is methyl isobutyl ketone, which comes from the wet phosphoric acid purification device of Wengfu Group, wherein the P2O5 content is 12% to 15%, and the SO4 2- The content is 0~1000mg / L.

[0078] Example 1

[0079] 400 mL of the loaded organic solvent was measured and placed in a 500 mL beaker, and 50 mL of desalted water was added for thorough mixing and mass transfer (using a high shear emulsifier, mixing at a temperature of 50°C and a rotation speed of 13000 rpm for 5 min). After standing for 1 h, the phases were separated to obtain stripped phosphoric acid and an unloaded organic solvent.

[0080] 10% by weight of activated carbon was added to the stripped phosphoric acid, and the mixture was stirred at 50° C. and 300 rpm for 10 min, and the resolved phosphoric acid was obtained by filtration.

[0081] Weigh 1.0054 g of the above-mentioned resolved phosphoric acid, put it into a 250 mL volumetric flask, add 1 mL of nitric acid solution, dilute to the scale with water, shake well, and obtain a sample solution.

[0082] Preparation of sulfate standard solution: Weigh 0.1480g of anhydrous sodium sulfate dried to constant weight at 105℃~110℃, dissolve in water, transfer to a 1000mL volumetric flask, and dilute to scale. Use a pipette to transfer 0.00mL, 2.00mL, 4.00mL, 6.00mL, 8.00mL, and 10.00mL of sulfate standard solution to a 100mL volumetric flask, add 5.0mL of nitric acid solution, dilute to scale with water, and shake well (fixed national standard method).

[0083] Standard working curve drawing: The above sulfate standard solutions are introduced into ICP in order from low concentration to high concentration, and the emission spectrum intensity is used as the ordinate, and the SO4 2- The mass concentration (mg / L) is used as the horizontal axis to draw the standard working curve. Figure 1 shown.

[0084] Use ICP to measure SO4 in the test solution 2- The emission spectrum intensity of the sample solution can be obtained based on the emission spectrum intensity of the sample solution and the standard working curve. 2- The mass concentration of SO4 in the sample solution is 20.6509 mg / L. 2- The mass fraction is 0.5135%.

[0085] According to the formula, the SO4 content in organic solvents can be calculated 2- The mass fraction is 0.0016%.

[0086] Take the same batch of organic solvents and directly measure SO4 under the same ICP conditions 2- Content 0.0047%.

[0087] Through the SO4 in the acid of this batch of products 2- The content of SO4 in the organic solvent loaded in this batch is calculated. 2-The theoretical value of the mass fraction is 0.0019%.

[0088] It can be seen that the relative error between the present invention and the theoretical value is 0.1579%, while the relative error between the traditional method and the theoretical value is 1.4737%.

[0089] Embodiments 2 to 4

[0090] See Table 1 below.

[0091] Table 1 Condition parameters, measurement method data, and accuracy data of Examples 1 to 4

[0092]

[0093] In summary, the determination method provided by the present invention has good accuracy, and the detection results are consistent with the SO4 2- The content is highly correlated, achieving the purpose of precise control of production.

[0094] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to the embodiments shown herein, but rather to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for determining the content of sulfate ions in an organic solvent, characterized in that: The following steps are involved: a) mixing the loaded organic solvent to be tested with the desalted water, and then standing and separating them to obtain stripped phosphoric acid and an empty organic solvent respectively; b) mixing the stripped phosphoric acid obtained in step a) with activated carbon, and filtering and separating the mixture to obtain resolved phosphoric acid; c) mixing the resolved phosphoric acid obtained in step b) with the nitric acid solution, and then fixing the volume with water to obtain a sample solution; d) Using ICP to measure the SO4 of the sample solution obtained in step c) 2- The emission spectrum intensity is consistent with the established SO4 2- Emission Spectrum Intensity-SO4 2- The mass concentration standard curve was compared to obtain the SO4 2- The mass concentration of sulfate ions in the organic solvent was calculated.

2. The method for determining the sulfate ion content in an organic solvent according to claim 1, wherein: The organic solvent to be tested in step a) is methyl isobutyl ketone obtained in the wet purification phosphoric acid process, wherein the mass concentration of P2O5 is 10% to 20%, SO4 2- The content is 0~1000mg / L.

3. The method for determining the sulfate ion content in an organic solvent according to claim 1, wherein: In step a), the volume ratio of the tested load organic solvent to the desalted water is (8-15):

1.

4. The method for determining the sulfate ion content in an organic solvent according to claim 1, wherein: The mixing device in step a) is a high shear emulsifier, the mixing temperature is 40° C. to 60° C., the rotation speed is 10000 rpm to 15000 rpm, and the mixing time is 3 min to 8 min.

5. The method for determining the sulfate ion content in an organic solvent according to claim 1, wherein: The process of static separation in step a) is specifically as follows: After the mixture is allowed to stand for 0.5 h to 1.5 h, it is phase-separated by a separatory funnel to obtain stripped phosphoric acid and an empty organic solvent, respectively.

6. The method for determining the sulfate ion content in an organic solvent according to claim 1, characterized in that: The amount of activated carbon added in step b) is 5% to 15% of the mass of the stripped phosphoric acid.

7. The method for determining the sulfate ion content in an organic solvent according to claim 1, wherein: The mixing temperature in step b) is 40° C. to 60° C., the rotation speed is 200 rpm to 400 rpm, and the time is 10 min to 15 min.

8. The method for determining the sulfate ion content in an organic solvent according to claim 1, characterized in that: In step c), the amount of the resolved phosphoric acid is 1 g, the amount of the nitric acid solution is 1 mL, and the volume is made up to 250 mL with water.

9. The method for determining the sulfate ion content in an organic solvent according to claim 1, characterized in that: In step d), SO4 2- Emission Spectrum Intensity-SO4 2- The specific process of establishing the mass concentration standard curve is as follows: First, prepare a sulfate standard solution. Weigh 0.1480 g of anhydrous sodium sulfate dried to constant weight at 105°C to 110°C, dissolve it in water, transfer it into a 1000 mL volumetric flask, and dilute to scale. Use a pipette to transfer 0.00 mL, 2.00 mL, 4.00 mL, 6.00 mL, 8.00 mL, and 10.00 mL of the sulfate standard solution into a 100 mL volumetric flask, add 5.0 mL of nitric acid solution, dilute to scale with water, and shake well. Then the above sulfate standard solutions are introduced into ICP in order from low concentration to high concentration, and the emission spectrum intensity is used as the vertical coordinate, and the SO4 2- The mass concentration of SO4 is plotted on the horizontal axis. 2- Emission Spectrum Intensity-SO4 2- Mass concentration standard curve.

10. The method for determining the sulfate ion content in an organic solvent according to claim 1, characterized in that: The calculation process in step d) is specifically as follows: First use the formula Calculate the SO4 in the sample solution 2- The quality score of Where: ω1 is the SO4 in the sample solution 2- The quality score of ρ1 is the SO4 in the sample solution found on the standard curve 2- The mass concentration of is in mg / L; 0.025 is the dilution factor; m1 is the mass of the sample solution, in g; SO4 in the above sample solution 2- The mass fraction of SO4 in phosphoric acid is 2- The quality score of Then use the formula Calculation of SO4 in organic solvents 2- The quality score of Where: ω2 is SO4 in organic solvent 2- Quality score; ω3 is SO4 in stripping phosphoric acid 2- Quality score; m2 is the mass of organic solvent, in g; m3 is the mass of stripped phosphoric acid, in g.

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