Method for detecting content of aluminum oxide in high-aluminum material

Abstract

The invention discloses a method for detecting the content of aluminum oxide in a high-aluminum material, based on the principle of EDTA complexometric titration, EDTA and aluminum ions form a stable complex (1gK = 16.1) in a buffer system with the pH value of 6.0, and the end point is judged according to the color change (brilliant yellow-purplish red) of an indicator, the method has the advantages that insoluble substances such as aluminum nitride can be completely decomposed by adopting alkali fusion pretreatment of YST 575.1, and full release of aluminum elements is ensured; by combining a GB / T 6900 titration system and optimizing a buffer condition and a masking agent, interference of iron (III), calcium, magnesium and the like is effectively overcome, so that the method has high accuracy and strong anti-interference performance (can tolerate Cl <-> of less than or equal to 3.5% and Fe of less than or equal to 1.8%), and is suitable for detection of aluminum ash residue recycling products with complex components.

Description

Technical Field

[0001] This invention relates to the field of alumina content detection technology for high-alumina materials, and particularly to a method for detecting alumina content in high-alumina materials. Background Technology

[0002] The stable operation and product quality control of aluminum ash slag resource utilization projects highly depend on accurate alumina content detection. Alumina slag mainly consists of elemental aluminum, alumina, and aluminum nitride. Through pretreatment methods such as crushing, ball milling, and screening, most of the metallic aluminum is recovered, while the remaining material enters a wet reaction system. In this system, elemental aluminum reacts with water to produce aluminum hydroxide and hydrogen, aluminum nitride hydrolyzes to produce ammonia and aluminum hydroxide, and alumina, as a stabilizing component, is retained and enriched in the final product, forming a high-alumina product with alumina content as the core indicator. However, the current process for detecting the component content of high-alumina products generated from aluminum ash slag resource utilization faces the dilemma of a lack of standards: due to the lack of unified testing standards, enterprises can only apply testing standards from various industries according to the different uses of high-alumina materials, resulting in inconsistent testing methods and poor data comparability.

[0003] This situation presents three prominent problems: First, different testing methods have different requirements for sample pretreatment, affecting the comparability of test results; second, differences in testing equipment cause data deviations; and third, the lack of unified quality control standards makes it difficult to effectively compare test data, resulting in fluctuations and incomparability of test data. The existence of these problems not only affects the stable control of production processes but also hinders the accurate assessment of product quality.

[0004] Therefore, establishing a scientific, stable, and practical method for detecting alumina content in high-alumina materials is crucial. This not only ensures the accuracy of production data and optimizes process parameters but also provides a reliable quality basis for the sale of high-alumina materials, enhancing customer trust and improving market competitiveness. Summary of the Invention

[0005] The main objective of this invention is to propose a method for detecting the alumina content of high-alumina materials, aiming to solve the problems mentioned in the background art, such as chaotic detection methods, inconsistent detection standards, poor data comparability, lack of continuity in detection data, inability to accurately reflect the alumina content of high-alumina materials, and inability to correctly guide the production and sales of aluminum ash slag projects.

[0006] To achieve the above objectives, the present invention proposes a method for detecting the alumina content of high-alumina materials, comprising the following steps:

[0007] S100. Sample pretreatment: The high-alumina sample is crushed, ball-milled and sieved to form high-alumina powder. The high-alumina powder is dried and placed in a desiccator to cool to room temperature. S200: Weigh m1 grams of the high-alumina sample obtained in step S100 and place it in a 30 ml platinum crucible. Add anhydrous sodium carbonate and boric acid, stir with platinum wire, cover the crucible, place it in a 100°C high-temperature furnace, heat to 1000°C and melt for 20 min, then remove and cool. S300. Sample decomposition: Add boiling water to the crucible and heat until the lumps are completely dissolved. Transfer the solution to a 250mL beaker. Rinse the crucible twice with hot water, then thoroughly clean it with 3 mL of hydrochloric acid and hot water. Add the washing solution to the beaker. Add hydrochloric acid to the beaker, cover it with a watch glass, and cool it to room temperature in a cold water bath. Transfer the solution to a 250mL volumetric flask. Rinse the beaker with water and add the washing solution to the volumetric flask. Dilute with water to the mark, shake well, and the sample solution is obtained. S400, titration: Transfer 50 mL of the test solution obtained in step S300 into a 200 mL volumetric flask using a pipette, dilute to about 150 mL, add 1-2 drops of phenolphthalein solution, neutralize with sodium hydroxide solution until the test solution turns just red, then add an excess of 8 mL, incubate in a 70℃ water bath for 30 min, remove, cool to room temperature, dilute with water to the mark, mix well, let stand for 10 min, filter dry with medium-speed filter paper, collect the filtrate in a dry beaker, and discard the initial 15 mL-20 mL of filtrate; S500: Transfer 100 mL of the filtrate obtained in step S400 using a pipette, add V2 mL of EDTA standard solution, neutralize the solution with hydrochloric acid solution until the red color disappears, and add 4 drops in excess to acidify it. Add 1 drop of bromophenol blue indicator solution, adjust the solution with ammonia water until it changes from yellow to blue, heat to boiling for 5 to 10 minutes, remove, cool to room temperature, add 15 mL of hexamethylenetetramine buffer solution with a pH of 5.5, 3 to 4 drops of xylenol orange indicator solution, add V3 mL of zinc acetate standard titration solution, and titrate until the test solution changes from yellow to purple-red as the endpoint. Calculate the alumina content of the high-alumina material based on the volume of zinc acetate standard titration solution consumed. S600: Repeat steps S200 to S500 three times for the same high-alumina sample, and perform three independent measurements. The alumina content of the high-alumina sample is taken as the average value.

[0008] Optionally, in step S500, the alumina content of the high-alumina material is expressed as a mass fraction, with the value expressed as... % indicates that the calculation is performed using the following formula:

[0009] In the formula: —The concentration of the EDTA standard solution is expressed in mol / L; —The volume of EDTA standard solution added, in mL; —The numerical value of the volume of zinc acetate standard titration solution used for back titration of excess EDTA standard solution, in mL; —The conversion factor between zinc acetate standard titration solution and EDTA standard solution; —The molar mass of aluminum oxide, in g / mol, M=101.961; —The mass value of the high-alumina sample, in grams.

[0010] Optionally, in step S100, a sieve with a pore size of 74 μm is used for screening.

[0011] Optionally, in step S100, the drying temperature of the high-alumina powder is 105 to 110°C, and the drying time is 2 hours.

[0012] Optionally, in step S200, the amount of anhydrous sodium carbonate added is 1.7g, and the amount of boric acid added is 0.8g.

[0013] Optionally, in step S400, the concentration of the sodium hydroxide solution is 500 g / L.

[0014] Optionally, the specific steps for determining the coefficient K for converting the zinc acetate standard titration solution to the EDTA standard solution are as follows: Transfer three 10 mL aliquots of EDTA standard solution to separate 400 mL beakers. Add water to approximately 200 mL, then add 15 mL of hexamethylenetetramine buffer solution, 1 drop of bromophenol blue indicator solution, and 3-4 drops of xylenol orange indicator solution. Titrate with zinc acetate standard titrant until the solution changes from yellow to purple-red. The range of the zinc acetate standard titrant consumed by the three EDTA standard solutions should not exceed 0.10 mL. Take the average value. The formula for calculating the coefficient K for converting the zinc acetate standard titrant to the EDTA standard solution is as follows:

[0015] In the formula: 10 — The volume of EDTA standard solution transferred, in mL; V – The average volume of the zinc acetate standard titration solution used in the titration, expressed in mL.

[0016] Optionally, the specific steps for determining the concentration of the EDTA standard solution are as follows: Transfer three 40 mL aliquots of 0.02 mol / L alumina standard solution to 400 mL beakers. Add 45 mL of EDTA standard solution, bring the volume to 200 mL, add 1 drop of bromophenol blue indicator solution, and adjust the solution with ammonia until it changes from yellow to blue. Heat to boiling for 5–10 minutes, remove from heat, and cool to room temperature. Add 15 mL of hexamethylenetetramine buffer solution and 2–3 drops of xylenol orange indicator solution. Titrate with zinc acetate standard solution until the solution changes from yellow to purplish-red. The range of the number of mL of zinc acetate standard solution consumed by the three alumina standard solutions should not exceed 0.10 mL. Take the average value. The concentration of the EDTA standard solution is expressed as molar concentration. Calculated, in units of mol / L. The calculation formula is:

[0017] In the formula: —The volume of alumina standard solution transferred, in mL; —The volume of EDTA standard solution added, in mL; —The average value of the volume of zinc acetate standard titration solution used for back-tipping excess EDTA standard solution, in mL; —The concentration of the alumina standard solution is expressed in mol / L; — The conversion factor between zinc acetate standard titration solution and EDTA standard solution.

[0018] Optionally, in step S400, the concentration of the phenolphthalein solution is 10 g / L, and it is prepared using a 60% ethanol solution.

[0019] Optionally, in step S500, the concentration of the xylenol orange indicator solution is 5 g / L, and the concentration of the bromophenol blue indicator solution is 18 g / L.

[0020] The technical solution of this invention has the following beneficial effects: 1. The technical solution of this invention is based on the principle of EDTA complexometric titration. In a buffer system with pH=6.0, EDTA forms a stable complex with aluminum ions (lgK=16.1). The endpoint is determined by the color change of the indicator (bright yellow → purplish red). The high-alumina sample is crushed, ball-milled, and sieved. It is then melted and decomposed with anhydrous sodium carbonate and boric acid at high temperature. After dissolution and volume adjustment, a portion of the sample solution is taken, neutralized with sodium hydroxide, treated with excess, and filtered to a final volume. The filtrate is then added to EDTA standard solution to complex aluminum ions. After acidification to adjust the acidity, it is heated to boiling. After cooling, a buffer solution and indicator are added, and the displaced EDTA is titrated with zinc acetate. The alumina content is calculated by the amount consumed. This solves the problem of inconsistent and incomparable test results from different standard methods. 2. Interference factor control: Optimal pretreatment conditions were selected to target common interfering elements in aluminum ash slag, such as chlorine and iron, which significantly improved the accuracy of detection and the ability to resist interference. 3. A standardized testing procedure for alumina content in high-alumina materials was established, significantly improving data repeatability. This method has good repeatability and stability, strong anti-interference ability, is easy to operate, and has good stability, meeting the daily testing needs of enterprises and solving the problem of inconsistent testing standards. 4. This method has good scalability and can be dynamically adjusted according to changes in raw materials and process development, leaving room for subsequent technological upgrades. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0022] Figure 1 This is a flowchart illustrating the steps of a method for detecting the alumina content of high-alumina materials according to an embodiment of the present invention.

[0023] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0024] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0025] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the present invention are only used to explain the relative positional relationship and movement of each component in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indication will also change accordingly.

[0026] Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or cannot be implemented, it should be considered that such combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0027] This invention proposes a method for detecting the alumina content in high-alumina materials.

[0028] like Figure 1 As shown, in one embodiment of the present invention, the method for detecting the alumina content of high-alumina materials includes the following steps: S100. Sample pretreatment: The high-alumina sample is crushed, ball-milled and sieved to form high-alumina powder. The high-alumina powder is dried and placed in a desiccator to cool to room temperature. S200: Weigh m1 grams of the high-alumina sample obtained in step S100 and place it in a 30 ml platinum crucible. Add anhydrous sodium carbonate and boric acid, stir with platinum wire, cover the crucible, place it in a 100°C high-temperature furnace, heat to 1000°C and melt for 20 min, then remove and cool. S300. Sample decomposition: Add boiling water to the crucible and heat until the lumps are completely dissolved. Transfer the solution to a 250mL beaker. Rinse the crucible twice with hot water, then thoroughly clean it with 3 mL of hydrochloric acid and hot water. Add the washing solution to the beaker. Add hydrochloric acid to the beaker, cover it with a watch glass, and cool it to room temperature in a cold water bath. Transfer the solution to a 250mL volumetric flask. Rinse the beaker with water and add the washing solution to the volumetric flask. Dilute with water to the mark, shake well, and the sample solution is obtained. S400, titration: Transfer 50 mL of the test solution obtained in step S300 into a 200 mL volumetric flask using a pipette, dilute to about 150 mL, add 1-2 drops of phenolphthalein solution, neutralize with sodium hydroxide solution until the test solution turns just red, then add an excess of 8 mL, incubate in a 70℃ water bath for 30 min, remove, cool to room temperature, dilute with water to the mark, mix well, let stand for 10 min, filter dry with medium-speed filter paper, collect the filtrate in a dry beaker, and discard the initial 15 mL-20 mL of filtrate; S500: Transfer 100 mL of the filtrate obtained in step S400 using a pipette, add V2 mL of EDTA standard solution, neutralize the solution with hydrochloric acid solution until the red color disappears, and add 4 drops in excess to acidify it. Add 1 drop of bromophenol blue indicator solution, adjust the solution with ammonia water until it changes from yellow to blue, heat to boiling for 5 to 10 minutes, remove, cool to room temperature, add 15 mL of hexamethylenetetramine buffer solution with a pH of 5.5, 3 to 4 drops of xylenol orange indicator solution, add V3 mL of zinc acetate standard titration solution, and titrate until the test solution changes from yellow to purple-red as the endpoint. Calculate the alumina content of the high-alumina material based on the volume of zinc acetate standard titration solution consumed. S600: Repeat steps S200 to S500 three times for the same high-alumina sample, and perform three independent measurements. The alumina content of the high-alumina sample is taken as the average value.

[0029] Specifically, in step S500, the alumina content of the high-alumina material is expressed as a mass fraction, with the value expressed as... % indicates that the calculation is performed using the following formula:

[0030] In the formula: —The concentration of the EDTA standard solution is expressed in mol / L; —The volume of EDTA standard solution added, in mL; —The numerical value of the volume of zinc acetate standard titration solution used for back titration of excess EDTA standard solution, in mL; —The conversion factor between zinc acetate standard titration solution and EDTA standard solution; —The molar mass of aluminum oxide, in g / mol, M=101.961; —The mass value of the high-alumina sample, in grams.

[0031] Specifically, in step S100, a sieve with a pore size of 74μm is used for screening.

[0032] Specifically, in step S100, the drying temperature of the high-alumina powder is 105 to 110°C, and the drying time is 2 hours.

[0033] Specifically, in step S200, the amount of anhydrous sodium carbonate added is 1.7g, and the amount of boric acid added is 0.8g.

[0034] Specifically, in step S400, the concentration of the sodium hydroxide solution is 500 g / L.

[0035] Specifically, the specific steps for determining the coefficient K for converting the zinc acetate standard titration solution to the EDTA standard solution are as follows: Transfer three 10 mL aliquots of EDTA standard solution to separate 400 mL beakers. Add water to approximately 200 mL, then add 15 mL of hexamethylenetetramine buffer solution, 1 drop of bromophenol blue indicator solution, and 3-4 drops of xylenol orange indicator solution. Titrate with zinc acetate standard titrant until the solution changes from yellow to purple-red. The range of the zinc acetate standard titrant consumed by the three EDTA standard solutions should not exceed 0.10 mL. Take the average value. The formula for calculating the coefficient K for converting the zinc acetate standard titrant to the EDTA standard solution is as follows:

[0036] In the formula: 10 — The volume of EDTA standard solution transferred, in mL; V – The average volume of the zinc acetate standard titration solution used in the titration, expressed in mL.

[0037] Optionally, the specific steps for determining the concentration of the EDTA standard solution are as follows: Transfer three 40 mL aliquots of 0.02 mol / L alumina standard solution to 400 mL beakers. Add 45 mL of EDTA standard solution, bring the volume to 200 mL, add 1 drop of bromophenol blue indicator solution, and adjust the solution with ammonia until it changes from yellow to blue. Heat to boiling for 5–10 minutes, remove from heat, and cool to room temperature. Add 15 mL of hexamethylenetetramine buffer solution and 2–3 drops of xylenol orange indicator solution. Titrate with zinc acetate standard solution until the solution changes from yellow to purplish-red. The range of the number of mL of zinc acetate standard solution consumed by the three alumina standard solutions should not exceed 0.10 mL. Take the average value. The concentration of the EDTA standard solution is expressed as molar concentration. Calculated, in units of mol / L. The calculation formula is:

[0038] In the formula: —The volume of alumina standard solution transferred, in mL; —The volume of EDTA standard solution added, in mL; —The average value of the volume of zinc acetate standard titration solution used for back-tipping excess EDTA standard solution, in mL; —The concentration of the alumina standard solution is expressed in mol / L; — The conversion factor between zinc acetate standard titration solution and EDTA standard solution.

[0039] Specifically, in step S400, the concentration of the phenolphthalein solution is 10 g / L, and it is prepared using a 60% ethanol solution.

[0040] Specifically, in step S500, the concentration of the xylenol orange indicator solution is 5 g / L, and the concentration of the bromophenol blue indicator solution is 18 g / L.

[0041] This invention is based on the principle of EDTA complexometric titration. In a buffer system with pH=6.0, EDTA forms a stable complex with aluminum ions (lgK=16.1). The endpoint is determined by the color change of the indicator (bright yellow → purplish red). Its advantages are: the use of YST575.1 for alkali fusion pretreatment can completely decompose sparingly soluble substances such as aluminum nitride, ensuring the full release of aluminum; combined with the titration system of GB / T 6900, the interference of iron(III), calcium, magnesium, etc. is effectively overcome by optimizing the buffer conditions and masking agent, so that the method has both high accuracy and strong anti-interference (able to withstand Cl). - (≤3.5%, Fe≤1.8%), suitable for the detection of resource products of aluminum ash slag with complex composition.

[0042] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the inventive concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A method for detecting the alumina content of high-alumina materials, characterized in that, Includes the following steps: S100. Sample pretreatment: The high-alumina sample is crushed, ball-milled and sieved to form high-alumina powder. The high-alumina powder is dried and placed in a desiccator to cool to room temperature. S200: Weigh m1 grams of the high-alumina sample obtained in step S100 and place it in a 30 ml platinum crucible. Add anhydrous sodium carbonate and boric acid, stir with platinum wire, cover the crucible, place it in a 100℃ high-temperature furnace, heat to 1000℃ and melt for 20 min, then take it out and cool. S300. Sample decomposition: Add boiling water to the crucible and heat until the lumps are completely dissolved. Transfer the solution to a 250mL beaker. Rinse the crucible twice with hot water, then thoroughly clean it with 3 mL of hydrochloric acid and hot water. Add the washing solution to the beaker. Add hydrochloric acid to the beaker, cover it with a watch glass, and cool it to room temperature in a cold water bath. Transfer the solution to a 250mL volumetric flask. Rinse the beaker with water and add the washing solution to the volumetric flask. Dilute with water to the mark, shake well, and the sample solution is obtained. S400, titration: Transfer 50 mL of the test solution obtained in step S300 into a 200 mL volumetric flask using a pipette, dilute to about 150 mL, add 1-2 drops of phenolphthalein solution, neutralize with sodium hydroxide solution until the test solution turns just red, then add an excess of 8 mL, incubate in a 70℃ water bath for 30 min, remove, cool to room temperature, dilute with water to the mark, mix well, let stand for 10 min, filter dry with medium-speed filter paper, collect the filtrate in a dry beaker, and discard the initial 15 mL-20 mL of filtrate; S500: Transfer 100 mL of the filtrate obtained in step S400 using a pipette, add V2 mL of EDTA standard solution, neutralize the solution with hydrochloric acid solution until the red color disappears, and add 4 drops in excess to acidify it. Add 1 drop of bromophenol blue indicator solution, adjust the solution with ammonia water until it changes from yellow to blue, heat to boiling for 5 to 10 minutes, remove, cool to room temperature, add 15 mL of hexamethylenetetramine buffer solution with a pH of 5.5, 3 to 4 drops of xylenol orange indicator solution, add V3 mL of zinc acetate standard titration solution, and titrate until the test solution changes from yellow to purple-red as the endpoint. Calculate the alumina content of the high-alumina material based on the volume of zinc acetate standard titration solution consumed. S600: Repeat steps S200 to S500 three times for the same high-alumina sample, and perform three independent measurements. The alumina content of the high-alumina sample is taken as the average value.

2. The method for detecting alumina content in high-alumina materials according to claim 1, characterized in that, In step S500, the alumina content of the high-alumina material is expressed as a mass fraction, with the value expressed as follows: % indicates that the calculation is performed using the following formula: In the formula: —The concentration of the EDTA standard solution is expressed in mol / L; —The volume of EDTA standard solution added, in mL; —The numerical value of the volume of zinc acetate standard titration solution used for back titration of excess EDTA standard solution, in mL; —The conversion factor between zinc acetate standard titration solution and EDTA standard solution; —The molar mass of aluminum oxide, in g / mol, M=101.961; —The mass value of the high-alumina sample, in grams.

3. The method for detecting the alumina content of high-alumina materials according to claim 1, characterized in that, In step S100, a sieve with a pore size of 74μm is used for screening.

4. The method for detecting alumina content in high-alumina materials according to claim 1, characterized in that, In step S100, the drying temperature of the high-alumina powder is 105 to 110°C, and the drying time is 2 hours.

5. The method for detecting the alumina content of high-alumina materials according to claim 1, characterized in that, In step S200, the amount of anhydrous sodium carbonate added is 1.7g, and the amount of boric acid added is 0.8g.

6. The method for detecting alumina content in high-alumina materials according to claim 1, characterized in that, In step S400, the concentration of the sodium hydroxide solution is 500 g / L.

7. The method for detecting alumina content in high-alumina materials according to claim 2, characterized in that, The specific steps for determining the coefficient K for converting the zinc acetate standard titration solution to the EDTA standard solution are as follows: Transfer three 10 mL aliquots of EDTA standard solution to separate 400 mL beakers. Add water to approximately 200 mL, then add 15 mL of hexamethylenetetramine buffer solution, 1 drop of bromophenol blue indicator solution, and 3-4 drops of xylenol orange indicator solution. Titrate with zinc acetate standard titrant until the solution changes from yellow to purple-red. The range of the zinc acetate standard titrant consumed by the three EDTA standard solutions should not exceed 0.10 mL. Take the average value. The formula for calculating the coefficient K for converting the zinc acetate standard titrant to the EDTA standard solution is as follows: In the formula: 10 — The numerical value of the volume of EDTA standard solution transferred, in mL; V – The average value of the volume of the zinc acetate standard titration solution used in the titration, in mL.

8. The method for detecting the alumina content of high-alumina materials according to claim 2, characterized in that, The specific steps for determining the concentration of the EDTA standard solution are as follows: Transfer three 40 mL aliquots of 0.02 mol / L alumina standard solution to 400 mL beakers. Add 45 mL of EDTA standard solution, bring the volume to 200 mL, add 1 drop of bromophenol blue indicator solution, and adjust the solution with ammonia until it changes from yellow to blue. Heat to boiling for 5–10 minutes, remove from heat, and cool to room temperature. Add 15 mL of hexamethylenetetramine buffer solution and 2–3 drops of xylenol orange indicator solution. Titrate with zinc acetate standard solution until the solution changes from yellow to purplish-red. The range of the number of mL of zinc acetate standard solution consumed by the three alumina standard solutions should not exceed 0.10 mL. Take the average value. The concentration of the EDTA standard solution is expressed as molar concentration. Calculated, in units of mol / L. The calculation formula is: In the formula: —The volume of alumina standard solution transferred, in mL; —The volume of EDTA standard solution added, in mL; —The average value of the volume of zinc acetate standard titration solution used for back-tipping excess EDTA standard solution, in mL; —The concentration of the alumina standard solution is expressed in mol / L; — The conversion factor between zinc acetate standard titration solution and EDTA standard solution.

9. The method for detecting the alumina content of high-alumina materials according to claim 1, characterized in that, In step S400, the concentration of the phenolphthalein solution is 10 g / L, and it is prepared using a 60% ethanol solution.

10. The method for detecting the alumina content of high-alumina materials according to claim 1, characterized in that, In step S500, the concentration of the xylenol orange indicator solution is 5 g / L, and the concentration of the bromophenol blue indicator solution is 18 g / L.

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