GB/T 8762.3-1988 Determination of acid-soluble silicon dioxide in fluorescent grade yttrium oxide Molybdenum blue spectrophotometric method GB/T8762.3-1988 standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Determination of acid soluble silicon dioxide in fluorescent grade oxide
Spectrophotometric method
Yttrium oxide of phosphorus grade-- Determinationof acid soluble silicon dioxide- Molybdenum blue photometric method
UDC 661.866
GB8762.388
This standard is applicable to the determination of acid soluble silicon dioxide in fluorescent grade oxide. Determination range: 0.0010%~~0.010%. This standard complies with GB1467--78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". 1 Method Summary
The sample is dissolved in hydrochloric acid. In a 0.06-0.12 mol/L sulfuric acid medium, silicon and ammonium molybdate generate yellow silicoaluminoacid. Oxalic acid and sulfuric acid mixed acid decompose phosphorus, arsenic heteropoly acid, and ascorbic acid reduce silicopoly acid to blue low-valent complex. Measure the absorbance at a spectrophotometer wavelength of 800 nm.
2 Reagents
2.1 Hydrochloric acid, high-grade pure (1+2).
2.2 Sulfuric acid, high-grade pure (1+5).
2.3 Ammonium molybdate solution, high-grade pure, (5%). Store in a plastic bottle. 2.4 Ammonia water, ultrapure (1+3).
2.5 Oxalic acid-sulfuric acid mixed acid: weigh 1g of high-grade pure oxalic acid and dissolve it in 100mL of sulfuric acid (2.2). 2.6 Ascorbic acid solution (5%): prepare it when used. 2.7 Silicon standard stock solution; accurately weigh 0.5000g of spectrally pure silica that has been pre-dried at 120℃ for 2h and cooled to room temperature in a desiccator, place in a platinum pot, add 5g of anhydrous sodium carbonate, melt at 950-1000℃ until clear, cool and leach with hot water, heat until the solution is clear, cool, transfer to a 500mL volumetric flask, dilute to scale with water, mix, and immediately transfer to a plastic bottle. This solution contains 1.0mg of silica in 1mL.
2.8 Silicon standard solution: transfer 10.00mL of silicon standard stock solution (2.7), place in a 1000mL volumetric flask, dilute to scale with water, mix, and immediately transfer to a plastic bottle. This solution contains 10μ silica in 1mL. 2.9 Water: ion exchange water is distilled sub-boilingly. This water is used for all reagent preparations. 2.10 Precision pH test paper: 0.5~5. 0.
3 Instruments and apparatus
3.1 Spectrophotometer.
3.2 Plastic cup (100mL)
Approved by China National Nonferrous Metals Industry Corporation on February 4, 1988 and implemented on February 1, 1989
4 Analysis steps
4.1 Quantity to be measured
GB 8762.3—-88
Weigh 2 samples for measurement and take the average value. 4.2 Sample quantity
Weigh the samples according to Table 1.
Silicon dioxide content
0. 001 0 ~ 0. 002 0
>0. 002 0 ~0. 005 0
≥0. 005 0 ~ 0. 010
4.3 Blank test
Carry out a blank test together with the sample.
4.4 Determination
Sample content
Hydrochloric acid content
4.4.1 Place the sample (4.2) in a 100mL plastic cup, add hydrochloric acid (2.1) according to Table 1, heat in a water bath, dissolve and cool. Transfer to a 50mL volumetric flask with water (2.9), dilute to scale and mix well. 4.4.2 Transfer 10.00mL of solution (4.4.1) to a 100mL plastic cup, and add ammonia water (2.4) dropwise while shaking until precipitation just appears. Use pH test paper (2.10) to test the acidity of the solution, which is about pH 3. 4.4.3 Add 0.4mL of sulfuric acid (2.2) and mix well. Add 2.5mL of ammonium molybdate solution (2.3), and place at room temperature not lower than 20℃ for 10min, then add 5mL of oxalic acid-sulfuric acid mixture (2.5) and mix well. Transfer to a 25mL colorimetric tube, add 2.5mL of ascorbic acid solution (2.6), dilute to the scale with water, and mix. Place for 10 min4.4.4 Transfer part of the solution (4.4.3) to a 3cm colorimetric tube, and use the blank accompanying the sample as a reference to measure its absorbance at a wavelength of 800nm ​​on a spectrophotometer. Find the corresponding amount of silica from the working curve. 4.5 Working curve drawing
4.5.1 Take 0, 0.2, 0.4, 0.6, 0.8, 1.0, 1.5mL of silicon standard solution (2.8) and place them in 25mL colorimetric tubes respectively, dilute to 10mL with water (2.9), and proceed as in 4.4.3. 4.5.2 Take part of the solution (4.5.1) in a 3cm colorimetric dish, use the reagent blank solution as a reference, and measure its absorbance at a wavelength of 800nm ​​on a spectrophotometer. Draw a working curve with the amount of silicon dioxide as the horizontal axis and the absorbance as the vertical axis. Calculation of analysis results
Calculate the percentage of silicon dioxide according to the following formula: mV
m. VX10g× 100
Sio(%) =
Wherein: m.
The amount of silicon dioxide found from the working curve, mL; total volume of test solution, mL;
V-volume of test solution taken, mL;
m - sample amount, g.
6 Allowable Difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. 8
Additional instructions:
Silicon dioxide content
0. 001 0~0. 003 0
≥0. 003 0 ~0. 007 0bzxz.net
>0. 007 0~0. 010
GB8762.3—88
This standard was drafted by Beijing General Research Institute of Nonferrous Metals and Shanghai Yuelong Chemical Plant. This standard was drafted by Shanghai Yuelong Chemical Plant. The main drafter of this standard is Minglong.
Allowable deviation
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