GB/T 14849.2-1993 Chemical analysis method for industrial silicon - Chrome azurol-S spectrophotometric method for determination of aluminum content GB/T14849.2-1993 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method for industrial silicon
Determination of aluminum content-- Chrome azurol S spectrophotometric method
Silicon metal-Determination of aluminum content-- Chrome azurol S spectrophotometric method1 Subject content and scope of application
This standard specifies the determination method of aluminum content in industrial silicon. This standard is applicable to the determination of aluminum content in industrial silicon. Determination range: 0.10%~1.20%. 2 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis method standards GB1467 General principles and general rules for chemical analysis method standards for metallurgical products GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Basic requirements for preparation
This standard is prepared in accordance with the regulations of GB1.4, GB1467 and GB7729. 4 Principle of the method
GB/T 14849.2--93
The sample is decomposed with hydrofluoric acid and nitric acid, and silicon, fluorine, etc. are removed with sulfuric acid fumes. The residue is dissolved with hydrochloric acid. Ascorbic acid is used to mask the interference of iron. In the hexamethylenetetramine medium with a pH of 5.5-6.1, aluminum and chrome azuro-S form a purple-red complex. The true absorbance is measured at a wavelength of 54nm on a spectrophotometer.
5 Reagents
5.1 Hydrofluoric acid (pl.14g/mL)
5.2 Nitric acid (1+1).
5.3 Sulfuric acid (1+1).
5.4 Hydrochloric acid 1--1).
5.5 Ascorbic acid solution (10/1.). Prepare it when needed. 5.6 Hexamethylenetetramine solution (300g/1.). 5.7 Chrome Azure-S ethanol solution (0.3 ml/L): Weigh 0.30 g Chrome Azure S in a beaker, add 25 ml of water and anhydrous ethanol to dissolve, then add 475 ml of water, dilute to 1000 ml with anhydrous ethanol, and mix well. 5.8 Aluminum standard storage solution: Weigh 0.2500 g of metal aluminum in a polyethylene cup, add about 20 ml of water and 3.0 ml of nitrogen fluoride, slowly dissolve, and heat in a water bath until completely dissolved. Use hydrochloric acid (5.4) to slowly neutralize until precipitation appears and add 20 ml of excess, heat the entire solution to clarify, and cool. Transfer to a 1000 ml volumetric flask, dilute to the mark with water, and mix well. This solution contains 250 ug of aluminum in 1 ml. 5.9 Aluminum standard solution: Pipette 10.00 mL aluminum standard storage solution (5.8) into a 500 mL volumetric flask. Add 4.0 mL acid (5.4) State Administration of Technical Supervision Approved on December 24, 1993 306
Implementation on September 1, 1994
GB/T14849.2-93
Dilute with water to the mark and mix well. This solution contains 5 μg aluminum in 1 mL. 6 Instruments
Spectrophotometer.
Analysis steps
7.1 Sample
The sample particle size passes through a 0.149 mm sieve diameter, and the iron powder is removed by a magnet. 7.2 Sample
Weigh 1.0000 g of sample (7.1).
7.3 Blank test
Carry out a blank test along with the sample.
7.4 DeterminationbZxz.net
7.4.1 Place the sample (7.2) in 100mL of platinum III, add 0.5mL of sulfuric acid (5.3), 20~25mL of hydrofluoric acid (5.1), and add nitric acid (5.2) dropwise until most of the sample is dissolved, move the platinum dish to a sand bath, heat until the sample is completely dissolved, and evaporate to dryness. 7.4.2 Place the platinum III in a high-temperature furnace at 450±25℃, until sulfuric acid fumes are exhausted, take it out, and cool it. 7.4.3 Add 5.0ml of hydrochloric acid (5.4) to the platinum dish, add 20~30mL of water along the wall of III, heat until the residue is completely dissolved, and cool it. Transfer the test solution into a 500mL volumetric flask, dilute to the mark with water, and mix well. This is test solution A. 7.4.4 Transfer 50.00mL of test solution A to a 250mL volumetric flask, dilute to the mark with water, and mix well. This is test solution B. 7.4.5 Pipette test solution B (7.4.4) according to Table 1 into a 100 ml volumetric flask and dilute with water to about 30 ml. Table 1
Aluminum content%
0.10~0.25
>0. 25~~0. 60
>0. 60~~1. 20
Pipette volume of test solution B, mL
7.4.6 Add 5 ml of ascorbic acid solution (5.5), 10.0 ml of chrome azurol-S ethanol solution (5.7), and 5.0 ml of hexamethylenetetramine solution (5.6). Mix each reagent. Dilute to the mark with water and mix. Let stand for 20 minutes. 7.4.7 Transfer part of the solution (7.4.6) into a 1 cm absorption dish, and measure its absorbance at a wavelength of 545 nm using the blank test solution (7.3) as a reference on a spectrophotometer.
7.4.8 Find the corresponding mass of aluminum from the working curve. 7.5 Drawing of the working curve
7.5.1 According to Table 1, transfer a blank test solution (7.3) equal in volume to that of test solution B into a set of 100 mL volumetric flasks, add 0.00, 1.00, 2.00, 3.00, 4.00, 5.00 ml of aluminum standard solution (5.9) to each, and dilute with water to about 30 ml. The following is carried out according to 7.4.6 and 7.4.7.
7.5.2 Draw a working curve using the mass of aluminum as the horizontal axis and the absorbance as the vertical axis. 8 Expression of analysis results
Calculate the percentage of aluminum by the following formula:
Al(%) - m Vo- Vs × 10
（1）
GB/T 14849.2-93
The mass of aluminum found from the working curve, μg; Where: mi----
V。-Total volume of test solution A, mL;
V,-—Volume of test solution A pipetted, mL;
V2-—Total volume of test solution B, mL;
V3-Volume of test solution B pipetted, ml.;
m。Mass of the test material, g.
9 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0.100~~0.400
>0.400～0.700
>0.700~1.200
Additional remarks:
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is drafted by Fushun Aluminum Plant.
This standard is drafted by Fushun Aluminum Plant.
The main drafter of this standard is Yu Min.
From the date of implementation of this standard, YB95-76 "Chemical Analysis Methods for Industrial Silicon" issued by the former Ministry of Metallurgical Industry of the People's Republic of China will be invalidated.
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