GB/T 19421-2026Test methods for crystalline layered sodium disilicate (English PDF)

4.2 Instruments and Equipment

4.2.1 X-ray diffractometer.

4.2.2 Agate mortar and pestle.

4.2.3 Sample preparation apparatus.

4.3 Procedure

4.3.1 Sample Preparation Weigh approximately 2g of the sample and grind it in a clean, dry agate mortar until the particle size is below 5µm, i.e., when rubbed between clean, dry fingers. The sample should be free of grittiness. Place the ground sample into the sample holder, fill it completely, and then gently press it down. The pressure should be enough to make the sample stand upright without collapsing after pressing.

4.3.2 Measurement Turn on the equipment cooling system and start the X-ray diffractometer, preheating for 30 minutes. Start the X-ray diffractometer control system and perform [operations/processes] on the diffractometer. Reference calibration. Under CuKalpha radiation, the sample (4.3.1) was scanned and measured in the range of 2theta from 10° to 50°.

4.3.3 Data Processing Using a data processing program, the X-ray diffraction pattern of the sample was obtained (see Appendix A), and the interplanar spacing (d) was marked on the diffraction peak positions. The obtained d-values are compared with those in Table

1.Diffraction lines that match the data in Table 1 are delta-phase layered crystalline sodium disilicate. Diffraction lines will appear; otherwise, other impurities will be present. When the content of delta-phase layered sodium disilicate in the sample is low, weaker spectral lines may not be visible. The presence of delta-phase layered crystalline sodium disilicate can be determined by the presence of three main strong lines.

4.16 Prepare and standardize a

0.1 mol/L standard titrant solution, then dilute it 10 times before use to obtain c(EDTA) =

0.01 mol/L standard titrant solution. Liquid (recalibrate if necessary).

7.2.2 Calcium chloride standard solution, c(CaCl2)=0.05mol/L; prepared and standardized according to section

4.8 of QB/T 2739-2005.

5.1 Instruments and Equipment

5.1.1 Standard Whiteboard A standard white plate conforming to GB/T 9086 is used for calibrating whiteness meters.

5.1.2 Whiteboard For ease of measurement, a smooth, unmarked, and crack-free white ceramic plate can be used as the working white plate for routine whiteness measurements. The whiteboard should be calibrated monthly using a standard whiteboard. The whiteboard should be stored in a desiccant in a dark place. If contaminated, it should be cleaned with a soft cloth or absorbent cotton. Wipe with anhydrous ethanol. Then place in a drying oven at 105°C~110°C for 30 minutes, remove, and cool to room temperature in a desiccator. Standard whiteboard calibration.

5.1.3 Whiteness meter The optical geometry of the instrument can be perpendicular/diffuse (o/d), diffuse/perpendicular (d/o), 45°/perpendicular (45°/o), and perpendicular/45° (o/ The instrument can be any of the following (45°) angles. The light source can be a D65 or C light source, and the instrument's reading accuracy must reach one decimal place. The instrument should... It meets the requirements of Level 2 or above in JJG512.

5.2 Procedure

5.2.1 Sampling The sample to be tested shall be reduced to a certain amount (not less than.200g) according to the sampling method specified in GB/T 13173 for testing.

5.2.2 Sample Preparation Select an appropriate sample quantity based on the sample density and the volume of the compactor, and compact the sample according to the steps specified in GB/T 9086 to form a smooth, non-greasy surface. Cracked and spotless sample plates were pressed in pairs for each sample.

5.2.3 Instrument Calibration Turn on, preheat, and adjust the instrument according to the instruction manual. Calibrate the instrument using a standard white board or working white board until it displays a stable nominal value.

5.2.4 Measurement of Whiteness After the instrument was calibrated and stabilized, the tristimulus values X, Y, Z, and R457 values for each sample plate were measured and recorded. For continuous measurements... During testing, the instrument should be calibrated with a standard whiteboard or working whiteboard as needed to eliminate the effects of instrument measurement drift.

5.3 Result Calculation

5.3.1 The neutral whiteness formula [Formula (1), Formula (2)] shall be used as the formula for calculating whiteness, and shall be consistent with the light tone formula [Formula (3), Formula (4)]. (4)] can be used together, and when necessary, the blue light whiteness formula [Formula (5)] can also be used for calculation.

5.3.3 If the instrument is a C-source light source, the tristimulus values Xc, Yc, and Zc measured under the C-source light source conditions are first converted according to formulas (6) to (8). Calculate the tristimulus values X, Y, and Z equivalent to the D65 light source conditions.

5.3.4 The arithmetic mean (rounded to the nearest whole number) of two parallel measurements of whiteness (with an error not exceeding 1.0%; if the error exceeds 1.0%, the measurement must be repeated) shall be used as the whiteness. The results are from the measurement. 6.pH Measurement

6.1 Principle Measure the potential difference of 1 g/L slurry, expressed as pH value.

6.2 Reagents

6.2.1 Unless otherwise specified, only reagents confirmed to be of analytical grade and water conforming to GB/T 6682 grade III or above shall be used in the analysis.

Note. This applies to all tests in this document.

6.2.2 Mixed phosphate buffer, pH=6.86 (25°C). Pour the commercially available mixed phosphate buffer into a 150mL beaker, add boiling and... Dissolve the contents in water cooled to room temperature, then transfer the solution to a 250 mL volumetric flask. Rinse the plastic bag with water, combine the solutions, make up to volume, and shake well.

6.2.3 Sodium tetraborate buffer, pH=9.18 (25°C). Pour commercially available sodium tetraborate into a 150mL beaker, add boiling water, and then cool. Dissolve the contents in room temperature water, then transfer the solution to a 250mL volumetric flask. Rinse the plastic bag with water, combine the solutions, make up to volume, and shake well.

6.3 Instruments

6.3.1 Magnetic stirrer.

6.3.2 pH meter. accuracy ±0.02pH.

6.3.3 Glass calomel electrodes or composite electrodes should be soaked in water for 24 hours before use.

6.4 Procedure

6.4.1 Sample Preparation The sample was dried in an oven at 105°C±2°C for 2 hours, then removed and placed in a desiccator to cool to room temperature before being weighed for later use.

6.4.2 Measurement Turn on the pH meter (6.3.2) and preheat for 30 minutes. Adjust the zero and full-scale readings according to the instrument's operating instructions, then add the mixed phosphate buffer sequentially. (6.2.2) and sodium tetraborate buffer (6.2.3) calibration. Weigh

0.1 g of the sample (6.4.1) (accurate to

0.001

g) into a 150 mL beaker, add 100 mL of water that has been boiled and cooled to room temperature, and place... After stirring with a magnetic stirrer (6.3.1) for 10 minutes, stop stirring and immediately insert the electrode. Read the value after the instrument has stabilized for 1 minute.

6.5 Test Results The result is the arithmetic mean of two parallel measurements, expressed to one decimal place.

6.6 Precision The absolute difference between two independent measurements obtained under repeatability conditions should not exceed

0.1 pH, and in cases where it exceeds

0.1 pH, it should not exceed [a certain value]. The premise is that it exceeds 5%.

7.2 Reagents

7.2.1 Standard titration solution of disodium ethylenediaminetetraacetate (EDTA), c(EDTA) =

0.01 mol/L; according to QB/T 2739-2005

7.2.3 Sodium hydroxide solution, c(NaOH) =

2.5 mol/L; Weigh 10 g of sodium hydroxide into a 250 mL beaker, dissolve in water, and then make up to volume. Pour into a 100 mL volumetric flask.

7.2.4 Sodium hydroxide solution, c(NaOH) =

0.5 mol/L; Weigh 2 g of sodium hydroxide into a 250 mL beaker, dissolve in water, and then dilute to a final volume. In a 100mL volumetric flask.

7.2.5 Calcium indicator; Take 1 part of sodium 2-hydroxy-1-(2-hydroxy-4-sulfonyl-1-naphthylazo)-3-naphthoate (sodium carboxylate, calcium reagent), and... Grind 100 parts of sodium chloride in a mortar until well mixed.

7.3 Instruments

7.3.1 Super thermostat.

7.3.2 Infinitely variable speed electric mixer.

7.4 Procedure

7.4.1 Sample Preparation The sample was dried in an oven at 105°C±2°C for 2 hours, then removed and placed in a desiccator to cool to room temperature before being weighed for later use.

7.4.2 Test Parts Weigh 0.5g of the sample (accurate to 0.001g).

7.4.3 Measurement Pipette

0.05 mol/L calcium chloride standard solution (7.2.2) into a 500 mL volumetric flask, and dilute with water to the mark. Mix thoroughly and transfer the mixture to a dry 1000mL beaker. Add a few drops of sodium hydroxide solution (7.2.4) to adjust the pH of the solution to 10.5. (Measured with a pH meter while stirring), heat to 35°C±1°C, add the test sample (7.4.2), and immediately place the beaker in a constant temperature environment. Stir for 20 minutes at 500 rpm in a water bath at 35°C±1°C. Remove and filter using dry, slow-speed qualitative filter paper. Discard 5 mL of filtrate. Once the filtrate has reached a certain volume, immediately transfer

50.0 mL to a 250 mL Erlenmeyer flask using a pipette, and add... 2 mL of

2.5 mol/L sodium hydroxide solution (7.2.3) and

0.06 g of calcium indicator (7.2.5) were titrated with EDTA standard titration solution (7.2.1). The final color change is from burgundy to blue.

7.6 Precision The absolute difference between two independent determinations obtained under repeatability conditions should not exceed 2 mg/g, and if it exceeds 2 mg/g, it should not exceed [a certain value]. The premise is that it exceeds 5%.

8.2 Reagents

8.2.1 Standard titration solution of disodium ethylenediaminetetraacetate (EDTA), c(EDTA) =

0.01 mol/L; according to QB/T 2739-2005

8.2.3 Ammonia-ammonium chloride buffer solution (pH=10); prepared according to

6.1 of QB/T 2739-2005.

8.2.4 Sodium hydroxide solution, c(NaOH) =

0.5 mol/L; Weigh 2 g of sodium hydroxide into a 250 mL beaker, dissolve in water, and then make up to volume. Pour into a 100 mL volumetric flask.

8.2.5 Acidic Chrome Blue K indicator; Take 0.3g Chrome Blue K, 0.75g Naphthol Green B and 50g potassium nitrate [pre-dried at 110°C±2°C] [1 hour, cool to room temperature] Grind and mix thoroughly.

8.3 Instruments

8.3.1 Super thermostat.

8.3.2 Infinitely variable speed electric mixer.

8.4 Procedure

8.4.1 Sample Preparation The sample was dried in an oven at (105±2)°C for 2 hours, then removed and placed in a desiccator to cool to room temperature for weighing.

8.4.2 Test Parts Take 0.5g of the sample and weigh it to an accuracy of 0.001g.

8.4.3 Measurement Pipette

0.05 mol/L magnesium chloride standard solution (8.2.2) into a 500 mL volumetric flask, and dilute with water to the mark. Mix thoroughly and transfer the mixture to a dry 1000mL beaker. Add a few drops of sodium hydroxide solution (8.2.4) to adjust the pH of the solution to 10.5. (Measured with a pH meter while stirring), heat to 35°C±1°C, add the test sample (8.4.2), and immediately place the beaker in a constant temperature environment. Stir for 20 minutes at 500 rpm in a water bath at 35°C±1°C. Remove and filter using dry, slow-speed qualitative filter paper. Discard 5 mL of filtrate. Once the filtrate reaches a certain volume, immediately transfer

50.0 mL to a 250 mL Erlenmeyer flask using a pipette, and add ammonia-chlorination... 15 mL of ammonium buffer solution (8.2.3) and

0.03 g of acidic chrome blue K indicator (8.2.5) were titrated with EDTA standard titration solution (8.2.1). The final step is when the purplish-red color turns into blue.

8.5 Result Calculation The magnesium ion exchange capacity H Mg is calculated according to formula (10).

8.6 Precision The absolute difference between two independent determinations obtained under repeatability conditions should not exceed 2 mg/g, and if it exceeds 2 mg/g, it should not exceed [a certain value]. The premise is that it exceeds 5%.

9.2 Instruments

9.2.1 High-temperature furnace, temperature control 800°C±10°C.

9.2.2 Porcelain crucible, capacity 30mL.

9.2.3 Dryer, filled with blue silica gel.

9.3 Procedure

9.3.1 Sample Preparation The sample was dried in an oven at 105°C±2°C for 2 hours, then removed and placed in a desiccator to cool to room temperature for weighing.

9.3.2 Measurement The empty porcelain crucible (9.2.2) was placed in a high-temperature furnace (9.2.1) at 800°C±10°C and heated for 1 hour. It was then removed and placed in a desiccator (9.2.3) to cool. Weigh the sample after it has cooled to room temperature, and repeat the above steps until the porcelain crucible (9.2.2) reaches a constant weight. Weigh approximately 1 g of the sample (9.3.1) (accurate to

0.001

g) into the already prepared crucible. The porcelain crucible (9.2.2) was heated to constant weight and placed in a high-temperature furnace at 800°C ±10°C for 1 hour. After removal, it was first placed in an oven at 105°C ±2°C. After cooling internally for about 10 minutes, place it in a desiccator and cool for 30 minutes before weighing.

9.4 Result Calculation The mass fraction of loss on ignition, wX, is calculated according to formula (11).

9.5 Precision The absolute difference between two independent determinations obtained under repeatability conditions should not exceed 0.01%, and in cases where it exceeds 0.01%, it should not exceed [a certain percentage]. The premise is 5%.

10.2 Instruments

10.2.1 Oven, temperature controlled at 105°C±2°C.

10.2.2 Weighing bottle, phi40mm ×25mm.

10.2.3 Dryer, filled with blue silica gel.

10.3 Procedure

10.3.1 Measurement Place the empty weighing bottle and cap (10.2.2) in an oven (10.2.1) at 105°C±2°C for 2 hours, then remove and place in a desiccator. In (10.2.3), after cooling for 30 minutes, weigh the sample. Weigh 1g of the sample (accurate to 0.001g) into a weighing bottle of known weight, cap the bottle, and weigh. Measure. Open the bottle cap and place it in an oven at 105°C±2°C for 2 hours. Remove it and place it in a desiccator to cool for 30 minutes. Tightly seal the bottle. Cover and weigh.

10.3.2 Result Calculation

10.4 Precision The absolute difference between two independent determinations obtained under repeatability conditions should not exceed 0.01%, and in cases where it exceeds 0.01%, it should not exceed [a certain percentage]. The premise is 5%.

11.2 Reagents

11.2.1 Hydrochloric acid (1.3, volume ratio).

11.2.2 Hydrochloric acid (1.1, volume ratio).

11.2.3 Ammonium fluoride, 100 g/L solution.

11.2.4 Boric acid, analytical grade, saturated solution.

11.2.5 o-phenanthroline.

11.2.6 Glacial acetic acid, density

11.2.7 Hydroxylamine hydrochloride.

11.2.8 Sodium acetate.

11.2.9 Mixed colorimetric reagent. Weigh

0.5 g of o-phenanthroline (11.2.5), add 2 mL of glacial acetic acid (11.2.6), dissolve, then add 500 mL of water and salt. 5g of hydroxylamine (11.2.7) and 100g of sodium acetate (11.2.8) were dissolved, filtered through rapid qualitative filter paper, and diluted to 1000mL.

11.2.10 Ferric oxide, content 99.99%.

11.2.11 Ferric oxide standard solution; accurately weigh

1.000 g of ferric oxide (11.2.10) after being calcined in a high-temperature furnace at 800°C±10°C for 1 h. Add 60 mL of hydrochloric acid (11.2.2) to a 250 mL beaker, cover with a watch glass, heat at a low temperature until completely dissolved, cool to room temperature, and transfer to a container. Dilute to the mark in a 1000mL volumetric flask and mix well. 1mL of this solution contains 1mg of ferric oxide.

11.2.12 Ferric oxide standard solution; transfer

5.0 mL of ferric oxide standard stock solution (11.2.11) into a 100 mL volumetric flask and dilute to the mark. Shake well.

11.3 Instruments

11.3.1 High-temperature furnace, with a temperature controllable range of 800°C±10°C.

11.3.2 Spectrophotometer with 1cm cuvette.

11.4 Test Procedure

11.4.1 Plotting the Standard Curve Add ferric oxide standard solution (11.2.12) to a set of 100 mL volumetric flasks, with volumes of

0.00 mL,

0.50 mL, and... Add

5.00 mL of hydrochloric acid (11.2.1), mix with 10 mL of colorimetric reagent (11.2.9), and add... Fill the water to the mark, shake well, and let stand for 10 minutes. Using a 1cm cuvette and water as a reference, measure the absorbance at a wavelength of 510nm. (The last sentence appears to be incomplete and possibly contains errors. It can be omitted from the translation.) A standard curve is plotted with concentration on the x-axis and net absorbance (absorbance minus zero concentration) on the y-axis.

11.4.2 Sample Preparation The sample was dried in an oven at 105°C±2°C for 2 hours, then removed and placed in a desiccator to cool to room temperature for weighing.

11.4.3 Measurement A blank test was performed simultaneously with the sample. Weigh

0.1 g of the sample (11.4.2) (accurate to

0.001

g) into a 150 mL beaker, add 5 mL of water, heat to a gentle boil for 1 min, and then add salt. Add 4 mL of acid (11.2.1) and heat to dissolve for 1 min. After cooling, add 4 mL of ammonium fluoride (11.2.3) and 5 mL of boric acid (11.2.4), then transfer to a 100 mL container. Add 10 mL of the mixed colorimetric reagent (11.2.9) to a volumetric flask, add water to the mark, shake well, and let stand for 10 minutes. Use a 1 cm cuvette, with water as a reference. The absorbance was measured at a wavelength of 510 nm. After subtracting the absorbance of the blank solution from the measured absorbance, the absorbance of the trioxide solution was determined from the standard curve.