GB/T 4700.5-1998 Chemical analysis methods for silicon-calcium alloys - Determination of carbon content by infrared absorption method

This standard specifies the infrared absorption method for the determination of carbon content. This standard is applicable to the determination of carbon content in silicon-calcium alloys. Determination range: 0.025%~1.200%. GB/T 4700.5-1998 Chemical analysis method for silicon-calcium alloys Determination of carbon content by infrared absorption method GB/T4700.5-1998 Standard download decompression password: www.bzxz.net

GB/T4700.5-1998
This standard is equivalent to JIS G1324-1989 "Chemical analysis method for silicon calcium alloy" in terms of technical content.
Compared with the original GB/T4700.5-1988, this revision adds the technical content of "Clean the dust in the instrument after each analysis". This standard replaces GB/T4700.5-1988 "Chemical analysis method for silicon calcium alloy - determination of carbon content by infrared absorption method" from the date of implementation.
This standard was proposed by the former Ministry of Metallurgical Industry of the People's Republic of China. This standard is under the jurisdiction of the Information Standards Research Institute of the former Ministry of Metallurgical Industry. The drafting units of this standard are Xinyu Iron and Steel Co., Ltd. and Jilin Ferroalloy Plant. The main drafters of this standard are You Youshen, Duan Qingguo, Dong Mingxue, Liao Yibing and Zhu Gaoping. This standard was first issued in February 1988.
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of calcium-silicon
Determination of carbon content by infrared absorption method
Methods for chemical analysis of calcium-siliconThe infrared absorption method for thedetermination of carbon contentThis standard specifies the determination of carbon content by infrared absorption method. This standard is applicable to the determination of carbon content in calcium-silicon alloy. Determination range: 0.025%～1.200%. 2 Summary of method
GB/T 4700. 5—1998
Replaces GB/T4700.5-1988
The sample is heated and burned in the oxygen flow of a high-frequency induction furnace. The generated carbon dioxide is carried by oxygen to the measuring chamber of the infrared detector. The carbon dioxide absorbs infrared energy of a specific wavelength. Its absorption energy is proportional to the concentration of carbon. The carbon content can be measured according to the change in the energy received by the detector. 3 Reagents and Materials
3.1 Acetone: The carbon content of the residue after evaporation is less than 0.0005%. 3.2 Magnesium perchlorate: Anhydrous, granular.
3.3 Caustic asbestos: Granular.
3.4 ​​Glass wool.
3.5 Tungsten particles: The carbon content is less than 0.002%, and the particle size is 0.8~1.4mm. 3.6 Tin particles: The carbon content is less than 0.002%, and the particle size is 0.4~0.8mm. If necessary, wash with acetone (3.1) and dry at room temperature. 3.7 Pure iron: The carbon content is less than 0.002%, and the particle size is 0.8~1.68mm. 3.8 Oxygen: The purity is greater than 99.95%. Other grades of oxygen can also be used if a low and consistent blank can be obtained. 3.9 Power gas source: Nitrogen or compressed air, and its impurity (water and oil) content is less than 0.5%. 3.10 Quality: outer diameter × height, 23mm × 23mm or 25mm × 25mm, and burned in a high temperature furnace above 1200°C for 4 hours, or burned with oxygen until the blank value is the lowest. 3.11 Crucible tongs.
4 Instruments and equipment
Infrared absorption carbon analyzer (sensitivity 0.1×10~6), its device is shown in Figure 1. Approved by the State Administration of Quality and Technical Supervision on December 7, 1998 156
Implemented on July 1, 1999
GB/T4700.5—1998 bzxZ.net
1- oxygen cylinder; 2- two-stage pressure regulator; 3- gas washing bottle; 4.9- drying tube; 5- pressure regulator; 6- high frequency induction furnace; 7- combustion tube; 8- dust collector; 10- flow controller; 11- converter for converting carbon oxide into carbon dioxide; 12- desulfurizer; 13- carbon dioxide infrared detector Figure 1 Diagram of infrared absorption carbon determination instrument
4.1.1 Gas washing bottle (Figure 1 Note 3): Contains caustic soda asbestos (3.3). 4.1.2 Drying tube (Figure 1 Note 4, 9): Contains magnesium perchlorate (3.2). 4.2 Gas source
4.2.1 The carrier gas system includes an oxygen container, a two-stage pressure regulator and a timing control part that ensures the provision of appropriate pressure and rated flow. 4.2.2 The power gas source system includes power gas (3.9), a two-stage pressure regulator and a timing control part that ensures the provision of appropriate pressure and rated flow.
4.3 High-frequency induction furnace
Should meet the requirements of the melting temperature of the sample.
4.4 Control system
4.4.1 The microprocessor system includes a central processing unit, a memory, a keyboard input device, an information center display panel, an analysis result display screen and an analysis result printer.
4.4.2 The control functions include automatic loading and unloading and furnace lifting, automatic cleaning, analysis condition selection and setting, analysis process monitoring and alarm interruption, analysis data collection, calculation, correction and processing, etc. 4.5 Measurement system
Mainly composed of an electronic balance (sensitivity not greater than 1.0 mg) controlled by a microprocessor, an infrared analyzer and electronic measuring elements. 5 Sample
The sample should pass through a 0.125 mm sieve.
6 Analysis steps
6.1 Sample quantity
Weigh 0.200~0.250 g of sample.
6.2 Blank test
Perform a blank test along with the sample.
6.3 Analysis preparation
Debug and check the instrument to ensure that it is in a normal and stable state, and select the best analysis conditions. 137
6.4 Calibration test
GB/T4700.5—1998
6.4.1 According to the carbon content of the sample to be tested, select the corresponding range or channel, and select three standard samples of the same type (the carbon content of the sample to be tested should fall within the range of the carbon content of the selected three standard samples), and calibrate in turn. The fluctuation of the measured results 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. 6.4.2 Different ranges or channels should measure their blank values ​​and calibrate them respectively. When the analysis conditions change, the blank should be re-measured and calibrated. 6.5 Determination
6.5.1 According to the carbon content range of the sample to be tested, select the best analysis conditions of the instrument. 6.5.2 Place the sample (6.1) in a crucible (3.10) which has been previously filled with 0.500g of tin particles (3.6) as the bottom, and 0.300g of pure iron (3.7) on top, and cover it with 0.400g of pure iron (3.7) and 1.500g of tungsten particles (3.5). Start the analysis and read the results. 6.5.3 Clean the dust in the instrument after each analysis. Allowable difference
The difference in the analysis results between laboratories should not be less than the allowable difference specified in Table 1. Table 1 Allowable difference
0. 025~0. 070
>0. 070~~0. 120
Allowable difference
>0. 120~0. 400
>0.400~1.200
Allowable difference
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