GB/T 4699.6-1988 Chemical analysis methods for silicon-chromium alloys - Determination of sulfur content by infrared absorption method

This standard is applicable to the determination of sulfur content in silicon-chromium alloys. Determination range: 0.005% to 0.015%. This standard complies with GB 1467-78 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products" GB/T 4699.6-1988 Chemical Analysis Method for Silicon-Chromium Alloys - Determination of Sulfur Content by Infrared Absorption Method GB/T4699.6-1988 Standard Download Decompression Password: www.bzxz.net

National Standard of the People's Republic of China
Methadsfor chemleal analysisof silicochromiuinThe infrared absorption method for ahe determinatlon of sulfur enntentThis standard is applicable to the determination of sulfur in silicon-chromium alloys. Determination range: 0.005%～0.015%. DC 669.78226
:543-062
GB 4699. 6—88
This standard complies with GB1467—78 "General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products". 1 Method Summary bZxz.net
The sample is heated and burned in the oxygen flow of a high-pressure induction furnace. The generated sulfur dioxide is carried by oxygen to the measuring chamber of the infrared analyzer. Sulfur dioxide absorbs infrared energy of a certain wavelength. Its absorption energy is proportional to the concentration of sulfur dioxide. The sulfur concentration can be measured according to the change in the energy received by the detector.
2 Reagents and Materials
2.1 Magnesium perchlorate; anhydrous, granular.
2.2 Caustic soda asbestos: granular,
2.3 Glass wool.
2.4 Tungsten granules: sulfur content less than 0.0002%, particle size 0.8~1.4mm. 2.5 Tungsten granules: sulfur content less than 0.0003%, particle size 0.4~0.8mm. 2.6 Pure iron: purity greater than 99.8%, sulfur content less than 0.002%, particle size 0.8~1.68mm2.7 Oxygen: purity greater than 99.95%, other levels of oxygen can also be used if a low and consistent blank can be obtained. 2.8 Power gas source: nitrogen or compressed air, with impurities (water and oil) less than 0.5%. 2.9 Quality crucible: ×, mm: 23×23 or 25×25, and burned in a high-temperature heating furnace above 1200℃ for 4b or burned with oxygen until the blank value is the lowest.
2.10 Crucible tongs.
Instruments and equipment
3.1 Infrared absorption sulfur analyzer (sensitivity is 1.0ppm) The device is shown in the figure.
The Ministry of Metallurgical Industry of the People's Republic of China approved on February 2, 1988 and implemented on March 1, 1989
GB 4699. 68B
1-gas cylinder; 2-two-stage repulsion regulator, 8-gas washing bottle; 4, 9-1 drying tube; 5-positive small regulator, 6-high pressure shield,? combustion zone, 8 dust removal path 10-flow controller; 11-infrared detection end of dioxide 3.1.1 Gas washing bottle (3), filled with caustic soda asbestos (2.2). 3.1.2 Drying tube (4.9). Filled with magnesium perfluoride (2.1). 3.2 Gas source
3.2.1 The carrier gas system includes an oxygen container, a two-stage pressure regulator and a timing control part to ensure the provision of appropriate positive pressure and rated flow. 3.3 High-frequency induction furnace
Should meet the requirements of the melting temperature of the sample.
3.4 ​​Control system
3.4.1 The microprocessor system includes a central processing unit, memory, keyboard input device, information center display screen, analysis result display screen and analysis result printer, etc.
3.4.2 Control functions include automatic loading and unloading and furnace lifting, mouth cleaning, analysis condition selection and setting, analysis process monitoring and alarm interruption, analysis data collection, calculation, calibration and processing, etc. 3.5 Measurement system
It is mainly composed of an electronic balance (sensitivity not greater than 1.0 mg) controlled by a microprocessor, an infrared analyzer and electronic measuring elements. 4 Sample
All samples should pass through a 0.125 mm sieve. 5 Analysis steps
5.1 Sample
Weigh 0.200 ~ 0.250 g of sample. 5.2 Blank test
Softly take 0.200~0.250g of low sulfur (less than 50ppm) standard sample of the same type as the sample to be tested and place it in a crucible (2.9) pre-filled with 0.600±0.005g pure iron (2.6), cover it with 0.500±0.005g tin particles (2.5) and 1.500±0.005g tungsten particles (2.4), and measure it in the same range or channel according to 5.5. Repeat it enough times until a low and relatively consistent reading is obtained (the blank value should be equal to the difference between the measured sulfur content and the known sulfur content of the standard sample). Record at least three readings, calculate the average blank value, and refer to the instrument manual to input the blank value into the analyzer. The instrument will then perform electronic compensation for the blank value when measuring the sample. 5.3 Analysis preparation
5.3.1 Debug and check the instrument according to the instrument manual to ensure that the instrument is in a normal and stable state. 5.3.2 Select samples and set the best analysis conditions.
GB 4699.688
5.3.3 Use standard sample and flux to make two tests according to 5.5 to determine whether the instrument is normal. 5.3. 4 Weigh 0.500 g of standard sample (or pure iron standard sample) with sulfur content of about 0.0035%, and measure according to 5.5. The result fluctuation should be within the range of ±0.000 3%, otherwise the instrument should be adjusted according to the instrument requirements. 5.4 Calibration test
5.4, 1 According to the sulfur content of the sample to be tested, select the corresponding range or channel, and select three standard samples of the same type (the content of the sample to be tested should fall within the sulfur content range of the selected three standard samples), and calibrate in turn. The fluctuation of the result should be within the allowable error range to confirm the linearity of the system, otherwise the linearity of the system should be adjusted according to the instrument manual. 5.4.2 For different ranges or channels, the blank values ​​should be measured and calibrated respectively. 5.4.3 When the analysis conditions change, such as when the oxygen source or flux blank value has changed before the instrument is heated for 1 hour, the blank value should be re-measured and calibrated.
5.5 Determination
5.5.1 According to the sulfur content range of the sample to be tested, select the best analysis parameters of the instrument respectively: such as the combustion integration time of the instrument, the setting of the comparison level (or set number), etc.
5.5.2 Place the sample (5.1) in a crucible (2.9) pre-filled with 0.600g pure iron (2.6), covering it with 4.50g tin particles (2.5) and 1.50g tungsten particles (2.4). Take the crucible with tongs and place it on the crucible seat on the furnace table. Operate according to the instrument manual, start analysis and read the results. 6 Allowable Difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. %
0. 005 ~~ 0. 015
Additional remarks,
This standard was drafted by Jilin Ferroalloy Factory.
The main drafter of this standard is Chang Yanfu.
Allowance difference
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB577-65 Silicon-Chromium Alloy Chemical Analysis Method" will be invalid. This standard level mark GB4699.6-881
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