GB/T 6609.5-2026Chemical analysis and physical property determination methods for alumina - Part 5: Determination of sodium oxide and potassium oxide contents (English PDF)

4.2.7 Sodium oxide and potassium oxide standard solutions. Transfer

50.00 mL of sodium oxide and potassium oxide standard stock solutions (4.2.6) into a 500 mL volumetric flask. Dilute with water to the mark, mix well, and store in a polyethylene bottle. 1 mL of this solution contains

0.1 mg sodium oxide and

0.01 mg potassium oxide.

4.3 Instruments and Equipment

4.3.1 Platinum crucible. 30 mL, with lid.

4.3.2 Muffle furnace. 1100°C±20°C.

4.3.3 Flame photometer. air-acetylene flame.

4.3.4 Dryer. Use activated alumina as a desiccant, and activate it at 300°C before each use.

4.4 Sample Sampling shall be carried out in accordance with the provisions of Chapter 6 of GB/T 6609.22-2026, and sample preparation shall be carried out in accordance with Section

7.4 of GB/T 6609.22-2026. The regulations shall be followed.

4.5 Test Procedure

4.5.1 Sample According to the different elements and contents (mass fractions) to be determined, weigh the sample (4.4) amount and melting amount according to Table 2, accurate to 0.0001g.

4.5.2 Parallel Tests Perform two parallel experiments and take the average value.

4.5.3 Blank Test A blank test was performed along with the sample.

4.5.4 Preparation of analytical solutions

4.5.4.1 Place the sample (4.5.1) in a platinum crucible (4.3.1), add the flux according to Table 2, stir well, cover with the platinum crucible lid, and place in a muffle furnace. (4.3.2) Heat from room temperature to 1100°C±20°C, hold for 10 minutes, and then remove.

4.5.4.2 Place the platinum crucible on a hot plate at a low temperature, add boiling water, and heat to near boiling to loosen the molten metal. Transfer the molten metal and solution to 150 mL. In a beaker, use a wiping rod to remove the precipitate from the platinum crucible wall, and wash with hot water. Add the washing solution to the beaker, ensuring the solution volume does not exceed [a certain value]. 70mL.

4.5.4.3 Place the beaker on a hot plate and heat until it just begins to boil. Use a flat-headed glass rod to crush the molten material, maintain the simmering state for 10 minutes, then remove and place in a cool environment. Cool to room temperature in a water bath.

4.5.4.4 Transfer the mixture of solution and precipitate (4.5.4.3) to a 100 mL volumetric flask, wash the beaker with water, and add the washings to the volumetric flask. Dilute with water to the mark and mix well. Filter using medium-speed quantitative filter paper [the filter paper and funnel should be washed four times with hydrochloric acid (4.2.3) and hot water]. Wash 5 times, then wash 2 to 3 times with the initial filtrate.

4.5.4.5 Transfer

40.00 mL of the filtrate (4.5.4.4) to a 50 mL volumetric flask, add

3.50 mL of n-butanol (4.2.5), shake, and allow the n-butanol to settle. Mix the alcohol (4.2.5) thoroughly, dilute with water to the mark, and mix well.

4.5.5 Measurement According to the instrument's operating conditions, use an air-acetylene flame on a flame photometer (4.3.3) at wavelengths of 589nm~590nm or 766nm~ At 770 nm, with water used for zeroing, the emission intensity of the analytical solution (4.5.4.5) and the blank test solution (4.5.3) prepared along with the sample were measured. The corresponding sodium oxide or potassium oxide content can be found on the working curve.

4.5.6 Plotting the Working Curve

4.5.6.1 In a set of 1000mL volumetric flasks, add sodium oxide and potassium oxide standard stock solutions (4.2.6) or sodium oxide and potassium oxide according to Table 3. Add 300 mL of boric acid solution (4.2.4) and 70 mL of n-butanol (4.2.5) sequentially to the standard solution (4.2.7), then add water to approximately 950 mL and shake. After dissolving n-butanol (4.2.5) by stirring, dilute with water to the mark, mix well, and store in a polyethylene bottle.

4.5.6.2 Using an air-acetylene flame, at wavelengths of 589 nm~590 nm and 766 nm~770 nm on a flame photometer (4.3.3), with water... Zero the instrument and measure the emission intensity of the series of standard solutions (4.5.6.1) respectively. Subtract the emission intensity of the "zero" concentration standard solution (the standard solution without sodium oxide and potassium oxide). The emission intensity of the standard solution was plotted as a working curve with sodium oxide content or potassium oxide content as the abscissa and emission intensity as the ordinate.

4.6 Experimental Data Processing The content (wi) of sodium oxide or potassium oxide is expressed as a mass fraction and calculated according to formula (1).

4.7 Precision

4.7.1 Repeatability The measured values of two independent test results obtained under repeatability conditions, within the range of the average values given in Table 4, represent the two measured values. The absolute difference does not exceed the repeatability limit (r), and the number of cases exceeding the repeatability limit (r) does not exceed 5%. The repeatability limit (r) is determined by linearity according to the data in Table 4. Obtained by interpolation or extrapolation.

4.7.2 Permissible Difference The difference between analytical results from different laboratories should not exceed the allowable difference listed in Table 5.

5.2.4 Aluminum matrix solution (

a) Aluminum matrix solution I. Weigh 3.306g of aluminum shavings [wAl>=99.99%], soak them in a small amount of nitric acid (1.3) beforehand, and then wash them with water to remove the nitric acid. [The acid (1 3) was rinsed twice with anhydrous ethanol or acetone and dried. It was placed in a 500 mL quartz beaker (5.3.1) and 125 mL of [acid] was added. Phosphoric acid (5.2.1), 25 mL sulfuric acid (5.2.2), cover with a watch glass, and after the vigorous reaction stops, slowly heat on a hot plate until complete. Once completely dissolved, immediately remove from heat and allow to cool naturally to 40°C~70°C. Rinse the watch glass with hot water, and combine the washings with the quartz beaker (5.3.1). Next, rinse the test solution with hot water into a 500mL volumetric flask, dilute with water to a final volume of approximately 400mL, mix well, and allow to cool naturally. Let it cool to room temperature, dilute with water to the mark, mix well, and store in a polyethylene bottle.

b) Aluminum matrix solution II. Weigh 3.306g of aluminum shavings [wAl>=99.99%], soak them in a small amount of nitric acid (1.3) beforehand, and then wash them with water to remove the nitric acid. [Acid (1 3), rinsed twice with anhydrous ethanol or acetone, and dried] placed in a 500 mL quartz beaker (5.3.1), and the total amount was added in portions. Add 250 mL of sulfuric acid (5.2.3), cover with a watch glass, and after the vigorous reaction stops, slowly heat on a hot plate until completely dissolved. Remove and allow to cool naturally to 40°C~70°C. Rinse the watch glass with hot water, and combine the washing solution with the quartz beaker (5.3.1). Then heat... Wash the test solution into a 500mL volumetric flask with water, dilute with water to a final volume of approximately 400mL, mix well, and allow to cool naturally to room temperature. Dilute with water to the mark, mix well, and store in a polyethylene bottle.

5.2.5 Standard stock solutions of sodium oxide and potassium oxide. Weigh 1.8859 g of sodium chloride (4.3.1) and place it in a platinum crucible at 500 °C. [Ignite for 2 hours, place in a desiccator (4.3.4), and allow to cool naturally to room temperature], 0.3166 g of standard potassium chloride [placed in a platinum crucible (4.3.1), and calcined at room temperature]. [Ignite at 500°C for 2 hours, place in a desiccator (4.3.4), and allow to cool naturally to room temperature] Dissolve in water in a 300mL beaker, then transfer to a.2000mL container. Dilute to the mark with water in a volumetric flask, mix well, and store in a polyethylene bottle. 1 mL of this solution contains

0.5 mg sodium oxide and

0.1 mg sodium hydroxide. Potassium. Or use a commercially available certified solution.

5.2.6 Sodium oxide and potassium oxide standard solutions. Transfer

10.00 mL of each of the sodium oxide and potassium oxide standard stock solutions (5.2.5) to a 100 mL volume. Dilute to the mark with water in a volumetric flask, mix well, and store in a polyethylene bottle. 1 mL of this solution contains

0.05 mg sodium oxide and

0.01 mg oxygen. Potassium hydroxide.

5.2.7 Sodium oxide standard solution. Transfer

10.00 mL of sodium oxide and potassium oxide standard stock solution (5.2.5) into a 500 mL volumetric flask, and add water. Dilute to the mark, mix well, and store in a polyethylene bottle. 1 mL of this solution contains

0.01 mg of sodium oxide.

5.3 Instruments and Equipment

5.3.1 Quartz beaker. 50mL.

5.3.2 Flame atomic absorption spectrometer, equipped with sodium and potassium hollow cathode lamps. Under optimal instrument operating conditions, flames that can achieve the following specifications... Atomic absorption spectrometers can be used.

---Characteristic Concentration. In a solution consistent with the matrix of the analytical solution, the characteristic concentrations of sodium oxide and potassium oxide should not exceed [value missing]. 0.015 µg/mL;

---Precision. The standard deviation of 10 absorbance measurements using the highest concentration standard solution should not exceed 1.0% of the average absorbance; Measure the absorbance 10 times using the lowest concentration standard solution (not the "zero" concentration standard solution), and the standard deviation should not exceed the highest concentration. The concentration is 0.5% of the average absorbance of the standard solution;

---Linearity of the working curve. The working curve is divided into 5 equal segments according to concentration. The absorbance difference of the highest segment and the absorbance difference of the lowest segment are... The ratio should be no less than 0.7.

5.3.3 Microwave digestion apparatus.

5.4 Test Procedure

5.4.1 Sample Weigh 0.25g of sample (4.4), accurate to 0.0001g, and record it as m0.

5.4.2 Parallel Tests Perform two parallel experiments and take the average value.

5.4.3 Blank Test A blank test was performed along with the sample.

5.4.4 Preparation of analytical solutions Different dissolution methods are used depending on the different ranges of sodium oxide or potassium oxide content.

---When the sodium oxide content (mass fraction) is 0.010%~1.000% or the potassium oxide content (mass fraction) is 0.020%~0.200% When necessary, sample dissolution method I can be used. place the sample (5.4.1) in a 50 mL quartz beaker (5.3.1), and add

5.0 mL of phosphoric acid (5.2.1). Add

1.0 mL of sulfuric acid (5.2.2), cover with a watch glass, and heat on a hot plate while shaking to dissolve. Wait until the sample (5.4.1) is completely dissolved. Then, immediately remove and cool to 40°C~70°C, rinse the watch glass with hot water, and pour the washing solution into a quartz beaker. Then rinse with hot water... Wash the test solution into the corresponding volumetric flask in Table 6, allow it to cool naturally to room temperature, dilute with water to the mark, and mix well.

---When the sodium oxide content (mass fraction) is 0.001%~1.000% or the potassium oxide content (mass fraction) is 0.002%~0.200% In this case, sample dissolution method II can be used. place the sample (5.4.1) in the digestion vessel of a microwave digester (5.3.3), and add 10 mL of sulfuric acid. (5.2.3) Close the digestion vessel lid, reinstall it in the microwave digester, and dissolve it according to the preset program. After the program is complete, remove the digestion vessel. Transfer the test solution into the corresponding volumetric flask in Table

6.Rinse the reaction vessel with water, and add the washings to the volumetric flask. Allow to cool naturally. Let it cool to room temperature, then dilute with water to the mark and mix well.

5.4.5 Measurement Using an air-acetylene flame on a flame atomic absorption spectrometer (5.3.2) according to the instrument's operating conditions, measurements were taken at wavelengths of 589.0 nm or... At 766.5 nm, zero the microscope with water and measure the absorbance of the analytical solution (5.4.4) and the blank solution (5.4.3) prepared along with the sample. The corresponding sodium oxide or potassium oxide mass concentration can be found on the curve.

5.4.6 Plotting the Working Curve

5.4.6.1 Based on the content of the element to be measured, the series of standard solutions shall be prepared as follows:

---When the sodium oxide content (mass fraction) is 0.001%~< 0.010%, take 0 mL,

0.25 mL,

0.50 mL, etc. respectively.

2.50 mL of sodium oxide standard solution (5.2.7) were placed in a set of 50 mL volumetric flasks. Depending on the different sample dissolution methods, add the corresponding

20.00 mL aluminum matrix solution (5.2.4), dilute with water to the mark, mix well, and store. In polyethylene bottles;

---Sodium oxide content (mass fraction) is 0.010%~< 0.100% or potassium oxide content (mass fraction) is 0.002%~0.020% At that time, 0 mL,

0.50 mL,

5.00 mL of sodium oxide and oxidant were respectively transferred. Potassium standard solution (5.2.6) is placed in a set of 100 mL volumetric flasks. Depending on the specific dissolution method, add the corresponding

20.00 mL of solution. The aluminum-based solution (5.2.4) was diluted with water to the mark, mixed well, and stored in a polyethylene bottle.

---Sodium oxide content (mass fraction) is 0.100%~1.000% or potassium oxide content (mass fraction) is 0.020%~0.200% At that time, transfer 0 mL,

0.50 mL,

5.00 mL of sodium oxide and potassium oxide, respectively. The standard stock solution (5.2.5) is placed in a set of 250 mL volumetric flasks. Depending on the different sample dissolution methods, add the corresponding

20.00 mL of the solution. The aluminum-based solution (5.2.4) is diluted with water to the mark, mixed well, and stored in a polyethylene bottle.

5.6 Precision

5.6.1 Repeatability The measured values of two independent test results obtained under repeatability conditions, within the range of the average values given in Table 7, represent the two test results. The absolute difference does not exceed the repeatability limit (r), and the number of cases exceeding the repeatability limit (r) does not exceed 5%. The repeatability limit (r) is determined by linearity according to the data in Table 7. Obtained by the intrinsic method or the extrapolation method.

5.6.2 Reproducibility Under reproducibility conditions, the measured values of the two independent test results, within the range of the average values given in Table 8, represent the two test results. The absolute difference should not exceed the reproducibility limit (R), and the number of cases exceeding the reproducibility limit (R) should not exceed 5%. The reproducibility limit (R) is calculated using linear regression based on the data in Table 8. Obtained by interpolation or extrapolation.

6.Test Report The test report should include the following.

---Measurement content;

---Document number;

---The method used;

---Analysis results and their representation;

---Differences from basic analytical procedures;

---Abnormal phenomena observed during the measurement;