Method for analyzing content of aluminum oxide in activated aluminum oxide

Abstract

The invention relates to the technical field of chemical analysis, and discloses a method for analyzing the content of aluminum oxide in activated aluminum oxide, which comprises the following steps: S1, drying an activated aluminum oxide sample through a high-temperature furnace; s2, slowly adding a small amount of water into the sample, stirring to be pasty, and adding a sulfuric acid solution for dissolving treatment; s3, transferring the to-be-detected liquid by using a transfer pipette, and putting the to-be-detected liquid into a 300mL conical flask; s4, washing the bottle wall with water, and adding 5-7 drops of xylenol orange indicating liquid; s5, adding an acetic acid-ammonium acetate buffer solution; and S6, calculating the aluminum oxide content according to a formula. The acetic acid-ammonium acetate buffer solution is used for replacing a traditional easy-to-explode reagent hexamethylenetetramine, so that the accuracy of aluminum oxide determination can be remarkably improved. The unique formula of the buffer solution can effectively stabilize the state of aluminum ions in a proper pH environment, promote effective combination of the aluminum ions and a reaction reagent and reduce the risk of complex decomposition, so that the reliability of an analysis result is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of chemical analysis, in particular to a method for analyzing the content of aluminum oxide in active aluminum oxide. BACKGROUND

[0002] In the analysis of active aluminum oxide, the content of aluminum oxide is a key indicator. The accurate determination of this indicator is related to the quality and application performance of industrial active aluminum oxide. The current industry standard HG / T 3927-2020 requires the use of hexamethylenetetramine as a pH buffer solution. Although this approach has achieved the analysis requirements to some extent, it has also brought some obvious shortcomings.

[0003] The safety of hexamethylenetetramine is a concern. As an easily explosive hazardous chemical, hexamethylenetetramine has a high risk in use and storage, which requires additional safety precautions in daily laboratory operations, increasing the complexity and risk of operation. This not only threatens the safety of laboratory personnel, but also increases the management cost of enterprises.

[0004] During the analysis process, the chemical properties of hexamethylenetetramine may affect the determination results. Its solution is alkaline, although it plays a role in stabilizing the pH value, but in the face of different samples, the fixed pH value may lead to the inadaptation of the reaction conditions. When the chemical properties of the sample change, the accuracy and reliability of the determination may be seriously affected, resulting in unstable analysis results. This is particularly troublesome in industrial applications, because the diversity of raw material sources may reduce the consistency of test results. SUMMARY

[0005] In view of the shortcomings of the prior art, the present application provides a method for analyzing the content of aluminum oxide in active aluminum oxide, which solves the safety hazards and unstable determination problems caused by using hexamethylenetetramine as a buffer in the prior art.

[0006] To achieve the above purpose, the present application is realized by the following technical scheme: a method for analyzing the content of aluminum oxide in active aluminum oxide, comprising: S1, drying the active aluminum oxide sample through a high temperature furnace, the temperature is 245-255℃, the time is 1.9-2.1 hours, then grinding to a particle size of ≤75μm to obtain a test sample; S2, slowly adding a small amount of water to the test sample, stirring to a paste, and adding a sulfuric acid solution for dissolution treatment, then heating and dissolving on an electric hot plate, transferring to a 100mL capacity bottle, diluting to the mark with water, shaking well to obtain a test solution; S3, using a pipette to transfer the test solution to a 300mL conical flask, and adding a disodium ethylenediaminetetraacetate standard solution to the test solution; S4, rinse the bottle wall with water, and add 5-7 drops of dimethyl phenol orange indicator solution, adjust the solution with ammonia solution, then move to the electric furnace to heat and boil, take off and cool, adjust to bright yellow with hydrochloric acid solution and add 1 drop more; S5, add acetic acid-ammonium acetate buffer solution, and titrate with zinc chloride standard solution until rose red appears as the end point; S6, calculate the content of aluminum oxide according to the formula, and take the arithmetic mean of the parallel determination results as the determination result, and the absolute difference of the two parallel determination results is not greater than 0.2%.

[0007] Preferably, the amount of sulfuric acid solution added in the S2 step is 9.5-10.5 mL / g, and the sulfuric acid and water in the sulfuric acid solution are mixed in a ratio of 1:1.

[0008] Preferably, the amount of the solution to be measured in the S3 step is 8-12 mL.

[0009] Preferably, the ethylenediaminetetraacetic acid disodium standard solution in the S3 step is prepared by the following steps; Weigh 18.11-19.11 g of working reference reagent ethylenediaminetetraacetic acid disodium placed in a saturated magnesium nitrate constant humidity chamber for 8-9 days; Dissolve in hot water at a temperature of 35-45°C, and then dilute to 1000 mL after cooling.

[0010] Preferably, the amount of ethylenediaminetetraacetic acid disodium standard solution added in the S3 step is 25-35 mL.

[0011] Preferably, the S4 specifically includes the following steps: Rinse the bottle wall with water; Add 5-7 drops of dimethyl phenol orange indicator solution to the conical flask; Add ammonia solution to mix until the solution is purple red; Move to the electric furnace to heat and boil for 30-90 seconds, then take off and cool.

[0012] Preferably, the dimethyl phenol orange indicator solution in the S4 step is an aqueous solution with a concentration of 2 g / L, the ammonia solution is obtained by mixing ammonia water and water in a ratio of 1:9, and the hydrochloric acid solution is obtained by mixing hydrochloric acid and water in a ratio of 1:4.

[0013] Preferably, the acetic acid-ammonium acetate buffer solution in the S5 step is prepared by the following steps: Weigh 298-301 g of ammonium acetate and dissolve in water; Add 0-7 mL of acetic acid and dilute to 1000 mL; Keep the pH at 6.5-7.0.

[0014] Preferably, the zinc chloride standard solution in the S5 step is prepared by the following steps; Weigh 4.07±0.20g of working reference reagent zinc oxide, which is calcined at 800℃±50℃ high temperature furnace to constant weight; Wet with a small amount of water, add 18mL of 20% hydrochloric acid solution, then move to a 1000mL volumetric flask and dilute to the mark.

[0015] Preferably, the aluminum trioxide content in the S6 step is the mass fraction of aluminum trioxide (Al2O3) The numerical value is expressed in %, calculated according to the following formula: ; In the formula, EDTA2- represents the accurate numerical value of the concentration of disodium ethylenediaminetetraacetate standard titration solution, mol / L; V2 represents the volume of EDTA standard titration solution added, mL; ZnCl2 represents the concentration of zinc chloride standard titration solution, mol / L; V1 represents the volume of zinc chloride standard titration solution consumed in titration, mL; V3 represents the volume of the sample to be tested, mL; W represents the mass of the sample, g; Al2O3 represents the molar mass of aluminum trioxide, g / mol.

[0016] The present application provides a method for analyzing the content of aluminum trioxide in active aluminum oxide. It has the following beneficial effects: 1. The present application can significantly improve the accuracy of aluminum trioxide determination by using acetic acid-ammonium acetate buffer instead of traditional explosive reagent hexamethylenetetramine. The unique formula of this buffer can effectively stabilize the state of aluminum ions in a suitable pH environment, promote their effective combination with reaction reagents, reduce the risk of complex decomposition, and at the same time provide a stable reaction environment for the complexation reaction of zinc chloride and EDTA, thereby improving the reliability of the analysis results.

[0017] 2. The present application uses acetic acid-ammonium acetate buffer with different pH values to effectively optimize the reaction environment of aluminum and improve the stability of aluminum ion complexes. Compared with the fixed pH buffer scheme in the prior art, the present application achieves higher determination accuracy by adjusting the pH, solves the problem of instability of traditional buffer in adapting to different samples, and enhances the reliability of the experiment. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1Flow chart of the method of the present application. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the specification of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the present application.

[0020] Please refer to the drawings in the specification of the present application Figure 1 The embodiment of the present application provides a method for analyzing the content of aluminum oxide in active aluminum oxide, which comprises.

[0021] Embodiment 1; 0.5000 g of active aluminum oxide powder was weighed and placed in a crucible, and then put into a high-temperature furnace for constant temperature drying at 250 DEG C for 2 hours. After taking out, it was ground to pass through a 200 mesh sieve (≤75 μm) using a agate mortar.

[0022] The ground sample was transferred to a 150 mL beaker, 5 mL of deionized water was added and stirred into a paste. 10 mL of sulfuric acid solution (concentrated sulfuric acid and water were mixed at a volume ratio of 1:1) was slowly added, and the solution was heated on an electric heating plate with the temperature setting at 300 DEG C. The solution was continuously heated under constant stirring until it became transparent. After cooling, the solution was diluted to 100 mL in a volumetric flask. There were no visible insoluble substances.

[0023] 10.00 mL of the sample solution was taken into a 300 mL conical flask, and 30.00 mL of disodium EDTA standard solution (0.050 mol / L, prepared by 18.11 g of reference reagent EDTA disodium after 8 days of equilibrium in a saturated magnesium nitrate constant humidity device) was added.

[0024] 6 drops of dimethyl phenol orange indicator solution (2 g / L) were added, and 1+9 ammonia water was added dropwise until the solution turned purple red (pH≈6.8). It was heated to micro-boiling on an electric furnace and kept for 60 seconds, and then naturally cooled to room temperature. Hydrochloric acid solution was added until it turned bright yellow, and then 1 drop of excess was added.

[0025] 10 mL of pH 6.5 acetic acid-ammonium acetate buffer solution (prepared: 299 g of ammonium acetate + 7 mL of glacial acetic acid to 1 L) was added.

[0026] 0.050 mol / L zinc chloride standard solution (4.07 g of reference zinc oxide was prepared after calcination at 800 DEG C) was titrated at a speed of 0.8 mL / min until the solution changed from bright yellow to rose red, and kept for 30 seconds without fading.

[0027] The content of aluminum oxide was calculated according to the following formula: The values ​​are expressed as % and are calculated using the following formula; ; In the formula, The accurate value in mol / L represents the concentration of the disodium ethylenediaminetetraacetate standard titration solution. This indicates the volume (mL) of EDTA standard titration solution added. This indicates the concentration of the zinc chloride standard titration solution in mol / L. This indicates the volume (mL) of zinc chloride standard titration solution consumed in the titration. V3 represents the volume (mL) of the sample to be tested; Indicates the mass of the sample, in grams; The value represents the molar mass of aluminum oxide (g / mol).

[0028] The arithmetic mean of the parallel measurement results is taken as the measurement result, and the absolute difference between two parallel measurement results is not greater than 0.2%.

[0029] Example 2; Weigh 0.4995g of sample, dry at 245℃ for 1.9 hours, and grind to ≤75μm.

[0030] Add 5 mL of water to form a paste, then add 9.5 mL of sulfuric acid solution (1+1). Place the mixture on a heating plate set to 280°C and heat continuously with constant stirring until the solution becomes clear. After cooling, dilute to a 100 mL volumetric flask. No visible insoluble matter should be present.

[0031] Transfer 8.00 mL of the test solution and add 25.00 mL of 0.048 mol / L EDTA solution (prepared by equilibration of 17.87 g disodium EDTA for 8 days).

[0032] Add 5 drops of indicator, adjust to pH 7.0, and boil for 55 seconds.

[0033] Remove and cool, then adjust the solution with hydrochloric acid until it turns bright yellow, then add an excess of 1 drop.

[0034] Add 9.5 mL of pH 6.5 buffer (298 g ammonium acetate + 6.5 mL acetic acid).

[0035] Titrate at a rate of 0.5 mL / min, and determine the endpoint color change as in Example 1.

[0036] ; In the formula, represents the accurate numerical value of the concentration of the EDTA standard titration solution in mol / L; represents the volume of the EDTA standard titration solution added in mL; represents the concentration of the zinc chloride standard titration solution in mol / L; represents the volume of the zinc chloride standard titration solution consumed in titration in mL; V3represents the volume of the sample taken for testing in mL; represents the mass of the sample in g; represents the molar mass of the aluminum oxide in g / mol.

[0037] The arithmetic mean of the parallel determination results is taken as the determination result, and the absolute difference between the two parallel determination results is not greater than 0.2%.

[0038] Example 3; 0.5010 g of the sample was weighed, dried at 255°C for 2.1 hours, and ground to ≤75 μm.

[0039] 5 mL of water was added to make a paste, 10.5 mL of sulfuric acid solution (1+1) was added, and the mixture was heated on an electric hot plate with the temperature set at 320°C. The heating was continued under constant stirring until the solution became transparent. After cooling, the solution was diluted to a 100 mL volumetric flask. No undissolved substance was visible to the naked eye.

[0040] 12.00 mL of the sample solution was taken, and 35.00 mL of 0.051 mol / L EDTA solution (19.11 g of EDTA disodium was equilibrated for 9 days to prepare) was added.

[0041] 7 drops of indicator were added, and the pH was adjusted to 7.1. Boiling was continued for 65 seconds.

[0042] The cooling was removed, and the solution was adjusted to bright yellow with hydrochloric acid solution, and 1 drop of excess was added.

[0043] 10.5 mL of pH 7.0 buffer solution (301 g of ammonium acetate, without acetic acid) was added.

[0044] The titration was performed at a speed of 1.0 mL / min, and the end point determination criteria were the same as in Example 1.

[0045] ; In the formula, represents the accurate numerical value of the concentration of the EDTA standard titration solution in mol / L; This indicates the volume (mL) of EDTA standard titration solution added. This indicates the concentration of the zinc chloride standard titration solution in mol / L. This indicates the volume (mL) of zinc chloride standard titration solution consumed in the titration. V3 represents the volume (mL) of the sample to be tested; Indicates the mass of the sample, in grams; The value represents the molar mass of aluminum oxide (g / mol).

[0046] The arithmetic mean of the parallel measurement results is taken as the measurement result, and the absolute difference between two parallel measurement results is not greater than 0.2%.

[0047] Comparative Example 1: Compared with Examples 1 and 3, the difference is that the pH of the acetic acid-ammonium acetate solution was adjusted to 4.5, while the other steps and parameters were the same.

[0048] Comparative Example 2: Compared with Examples 1 and 3, the difference is that the pH of the acetic acid-ammonium acetate solution was adjusted to 5.5, while the other steps and parameters were the same.

[0049] Comparative Example 3: Compared with Examples 1 and 3, the difference is that hexamethylenetetramine is used as a buffer solution, while the other steps and parameters are the same.

[0050] Comparative Example 4: Compared with Examples 1 and 3, the difference is that the pH of the acetic acid-ammonium acetate solution was adjusted to 6.0, while the other steps and parameters were the same.

[0051] Experimental Example 1: Comparison of the effects of acetic acid-ammonium acetate buffer solution as a substitute for hexamethylenetetramine Objective: Using analytical grade activated alumina as the sample, this study investigated the effects of acetate-ammonium acetate buffer solutions at different pH values ​​on hexamethylenetetramine and compared the results in the determination of its alumina content.

[0052] Experimental group: Example 1: Using an acetate-ammonium acetate buffer solution at pH 6.5 Example 3: Using an acetate-ammonium acetate buffer solution at pH 7.0 Comparative Example 1: Using an acetate-ammonium acetate buffer at pH 4.5 Comparative Example 2: Using an acetate-ammonium acetate buffer at pH 5.5 Comparative Example 3: Hexamethylenetetramine was used as a buffer solution (1.5 g). Experimental steps: Sample weighing: Take 0.5 g of the sample of active alumina of analytical purity. Ensure that the same mass of sample is used for each experimental group.

[0053] Test solution preparation: Add the weighed sample to a conical flask, add an appropriate amount of deionized water and stir to form a uniform test solution. Note that complete mixing is maintained at each operational step to avoid precipitation.

[0054] Titration process: In each conical flask, add the respective buffer solution step by step. Use the zinc chloride standard solution for back titration, observing the color change.

[0055] During titration, add the zinc chloride solution slowly until the solution color changes from yellow to rose red, recording the end point of the reaction.

[0056] Data recording: Record the consumption of zinc chloride in each experimental group and calculate the corresponding aluminum trioxide content based on the consumption.

[0057] The experimental data are shown in Table 1; Table 1 Summary: This experiment aims to compare the effects of different pH values of acetic acid-ammonium acetate buffer solution and hexamethylenetetramine on the determination of aluminum trioxide content. The experimental results show that the acetic acid-ammonium acetate buffer solution exhibits excellent buffering capacity in terms of pH adjustment, especially at pH 6.5 and 7.0, which can effectively maintain the pH stability of the solution. This feature provides a good environment for subsequent reactions.

[0058] By comparing buffer solutions under different pH conditions, it is found that the appropriate pH value has a significant impact on the determination results of aluminum trioxide. At pH 6.5 and pH 7.0, the buffering capacity of the acetic acid-ammonium acetate buffer solution can ensure that aluminum ions are in the best state, fully reacting with reagents such as EDTA, which provides reliable support for the back titration of the zinc chloride standard solution, thereby improving the accuracy and reproducibility of the determination.

[0059] Experimental Example 2: Verification of the effect of replacing hexamethylenetetramine with acetic acid-ammonium acetate buffer solution Objective: To use active alumina of analytical purity as a sample to verify the effects of different pH values of acetic acid-ammonium acetate buffer solution and hexamethylenetetramine in determining aluminum trioxide content.

[0060] Experimental groups: Example 1: Use of pH 6.5 acetic acid-ammonium acetate buffer solution Example 3: Use of pH 7.0 acetic acid-ammonium acetate buffer solution Comparative Example 2: Using acetic acid-ammonium acetate buffer at pH 5.5 Comparative Example 3: Using 1.5g hexamethylenetetramine as buffer Comparative Example 4: Using acetic acid-ammonium acetate buffer at pH 6.0 Experimental Procedure: Sample Preparation: Weigh 0.5g of analytical pure activated alumina and distribute it into different experimental groups, ensuring the consistency of sample mass.

[0061] Test Solution Preparation: Add an appropriate amount of deionized water to each group of samples, stir evenly to form a uniform test solution. The stirring time and intensity of each group should be consistent to reduce experimental errors.

[0062] Buffer Addition and Titration Process: Gradually add the pre-prepared buffer to the suspension, monitor the pH change of each group of solutions. Use pH paper or pH meter to test regularly to ensure it is maintained within the target pH range.

[0063] Use zinc chloride standard solution for back titration, slowly drop into the solution until the color change is observed (yellow to rose red). Record the consumption of zinc chloride, ensure accurate operation to obtain consistent data.

[0064] Data Recording and Arrangement: Record the consumption of zinc chloride for each group, and calculate the content of aluminum oxide (expressed as mass percentage). Ensure that at least three repeated experiments are performed for each group during the experiment, and record the consumption of each time for data comparison.

[0065] Data Analysis: Organize the collected data and use table form to compare and analyze the results of different experimental groups, especially pay attention to the change of aluminum oxide content and the corresponding consumption of zinc chloride between groups.

[0066] The experimental data is shown in Table 2; Table 2 Summary: In the acetic acid-ammonium acetate buffer solution with pH of 6.5 and 7.0, the error between the determination results of aluminum oxide and hexamethylenetetramine is within 0.2%. This shows that under these two pH conditions, the acetic acid-ammonium acetate buffer can effectively stabilize the chemical environment of aluminum, thereby improving the accuracy of aluminum oxide determination. This mechanism reflects the core principle of the role of buffer, in which the appropriate pH value promotes the effective combination of aluminum and reaction reagents.

[0067] The acetic acid-ammonium acetate buffer effectively maintains the chemical environment stability of aluminum ion complexes under these two pH conditions, thereby improving the accuracy of aluminum oxide determination. The appropriate pH value promotes the effective combination between aluminum ions and reaction reagents, ensures the smooth progress of the reaction, and reduces possible interference during the experiment.

[0068] Through comparison of the data of each experimental group, it is found that the determination results of acetic acid-ammonium acetate buffer at pH 6.0 and 5.5 are slightly lower than those at pH 6.5 and 7.0, which further emphasizes the importance of pH value on the reaction ability of aluminum ions.

[0069] Experimental Example 3: Verification of the replacement effect of acetic acid-ammonium acetate buffer solution in different active aluminum oxide samples Objective: Using analytical pure active aluminum oxide, new samples and old samples, compare the effects of acetic acid-ammonium acetate buffer solution at pH≈6.5 and pH≈7.0 and hexamethyl tetramine in determining the content of aluminum oxide.

[0070] Experimental groups: Example 1: Using acetic acid-ammonium acetate buffer solution at pH≈6.5 Example 3: Using acetic acid-ammonium acetate buffer solution at pH≈7.0 Comparative Example 3: Using 1.5g hexamethyl tetramine as buffer Experimental steps: Sample preparation: Weigh 0.5g of each of the three active aluminum oxide samples: analytical pure active aluminum oxide, new samples (unused industrial active aluminum oxide) and old samples (active aluminum oxide after device use). Ensure the quality of each sample is consistent.

[0071] Test solution preparation: Put each sample separately into a conical flask, add an appropriate amount of deionized water, and stir well to form a uniform test solution. Each group should maintain consistent stirring time to ensure uniformity of the reaction.

[0072] Buffer addition and titration process: Gradually add acetic acid-ammonium acetate buffer solution of different pH values (pH 6.5 for Example 1 and pH 7.0 for Example 3) and hexamethyl tetramine control group to the suspension, respectively. Use zinc chloride standard solution for back titration, slowly drop until the solution color changes from yellow to rose red, and record the consumption of zinc chloride.

[0073] Data recording and analysis: The experiment was repeated at least three times for each sample, and the zinc chloride consumption was recorded each time. Based on these data, the corresponding aluminum trioxide content (expressed as a percentage by mass) was calculated, and the data from each set of experiments were collated for comparative analysis.

[0074] Results collation: All experimental data were collated into a table to compare the aluminum trioxide content and zinc chloride consumption of different samples under different buffer conditions, and to observe the effect of the buffer on each sample.

[0075] The experimental data are shown in Table 3; Table 3 Summary: The present experiment aims to verify the effect of acetic acid-ammonium acetate buffer at pH ≈ 6.5 and pH ≈ 7.0 as a substitute for hexamethylenetetramine in active alumina samples of different origins (analytical pure, new sample, and old sample). The experimental results are compared by determining the aluminum trioxide content, with the aim of evaluating the application potential of acetic acid-ammonium acetate buffer in different samples.

[0076] The experimental data show that, under the use of acetic acid-ammonium acetate buffer at pH ≈ 6.5 and pH ≈ 7.0, the analytical pure active alumina determination results show a high degree of consistency, all within the range of 94.95%-95.02%, while the aluminum trioxide content of the new sample is between 91.75%-92.00%. This shows good repeatability and accuracy. The determination results of the new sample are between 91.75%-92.00%, indicating that its content is still relatively high and suitable for further analysis.

[0077] The key results show that acetic acid-ammonium acetate buffer can effectively replace hexamethylenetetramine under these conditions, especially in analytical pure samples and new samples, showing good determination accuracy, and the consumption of zinc chloride remains consistent.

[0078] Although embodiments of the present application have been shown and described, it will be understood by those of ordinary skill in the art that various changes, modifications, substitutions and alterations can be made thereto without departing from the principles and spirit of the present application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A method for analyzing the aluminum oxide content in activated alumina, characterized in that, include: S1. Dry the activated alumina sample in a high-temperature furnace at 245-255℃ for 1.9-2.1 hours, then grind it to a particle size ≤75μm to obtain the sample. S2. Slowly add a small amount of water to the sample, stir until it becomes a paste, add sulfuric acid solution to dissolve it, then transfer it to a hot plate to heat and dissolve it. Transfer it to a 100mL volumetric flask, dilute it with water to the mark, shake well, and obtain the test solution. S3. Use a pipette to transfer the test solution into a 300mL Erlenmeyer flask, and add the disodium ethylenediaminetetraacetate standard solution to the test solution; S4. Rinse the bottle wall with water and add 5-7 drops of xylenol orange indicator solution. Adjust the solution with ammonia solution, then heat it to boiling on an electric stove. Remove it and cool it. Adjust the solution with hydrochloric acid solution until it turns bright yellow, then add 1 drop in excess. S5. Add acetic acid-ammonium acetate buffer solution and titrate with zinc chloride standard solution until a rose-red color appears, which is the endpoint. S6. Calculate the aluminum oxide content according to the formula, and take the arithmetic mean of the parallel determination results as the determination result. The absolute difference between the two parallel determination results shall not be greater than 0.2%.

2. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, In step S2, the amount of sulfuric acid solution added is 9.5-10.5 mL / g, and the sulfuric acid solution is obtained by mixing sulfuric acid and water in a 1:1 ratio.

3. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, In step S3, the volume of the test solution transferred is 8-12 mL.

4. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, The disodium ethylenediaminetetraacetate standard solution in step S3 is prepared through the following steps; Weigh 18.11-19.11g of disodium ethylenediaminetetraacetate, a working standard reagent, which has been placed in a saturated magnesium nitrate humidifier for 8-9 days; Dissolves in hot water at 35-45℃, and after cooling, bring the volume to 1000mL.

5. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, In step S3, the amount of disodium ethylenediaminetetraacetate standard solution added is 25-35 mL.

6. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, S4 specifically includes the following steps; Pour water into the conical flask to rinse the flask walls; Add 5-7 drops of xylenol orange indicator solution to the conical flask; Add ammonia solution and mix until the solution turns purple-red; Transfer to an electric stove and heat to boiling for 30-90 seconds, then remove and let cool.

7. The method for analyzing the aluminum oxide content in activated alumina according to claim 6, characterized in that, In step S4, the xylenol orange indicator solution is an aqueous solution with a concentration of 2 g / L. The ammonia solution is obtained by mixing ammonia and water in a ratio of 1:

9. The hydrochloric acid solution is obtained by mixing hydrochloric acid and water in a ratio of 1:

4.

8. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, The acetate-ammonium acetate buffer solution in step S5 is prepared through the following steps; Weigh 298-301g of ammonium acetate and dissolve it in water; Add 0-7 mL of acetic acid and dilute to 1000 mL; Maintain the pH at 6.5-7.

0.

9. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, The zinc chloride standard solution in step S5 is prepared through the following steps; Weigh 4.07±0.20g of zinc oxide, a working standard reagent, and calcine it to constant weight in a high-temperature furnace at 800℃±50℃. Moisten with a small amount of water, dissolve in 18 mL of 20% hydrochloric acid solution, transfer to a 1000 mL volumetric flask, and dilute to the mark.

10. The method for analyzing the aluminum oxide content in activated alumina according to claim 1, characterized in that, In step S6, the aluminum oxide content is expressed as a mass fraction of aluminum oxide. The values ​​are expressed as % and are calculated using the following formula; ； In the formula, The accurate value in mol / L represents the concentration of the disodium ethylenediaminetetraacetate standard titration solution. This indicates the volume (mL) of EDTA standard titration solution added; This indicates the concentration of the zinc chloride standard titration solution in mol / L. This indicates the volume (mL) of zinc chloride standard titration solution consumed in the titration. V3 represents the volume (mL) of the sample to be tested; Indicates the mass of the sample, in grams; The value represents the molar mass of aluminum oxide (g / mol).

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