This standard is equivalent to ΓOCT 2978.1~.10-78 "Methods for chemical analysis of melting flux". This standard is a revision of JB/T 7948.9-95 "Methods for chemical analysis of melting flux - Determination of sodium oxide and potassium oxide by flame photometry". During the revision, only editorial changes were made according to relevant regulations, and its technical content has not changed. This standard is applicable to the determination of sodium oxide and potassium oxide in melting flux, with a determination range of 0.20%~3.00%. This standard was first issued in 1985 as GB 5292.9-85 and was adjusted to JB/T 7948.9-95 in April 1996. JB/T 7948.9-1999 Methods for chemical analysis of melting flux - Determination of sodium oxide and potassium oxide by flame photometry JB/T7948.9-1999 Standard download decompression password: www.bzxz.net

JB/T 7948.9—1999
This standard is equivalent to TOCT22978.1～22978.10—78≤Method for Chemical Analysis of Melting Fluxes. This standard is a revision of JB/T7948.9—95 "Method for Chemical Analysis of Melting Fluxes - Flame Photometry for Determination of Sodium Oxide and Potassium Oxide". During the revision, only editorial changes were made to the standard, and its technical content remained unchanged. This standard replaces JB/T7948.9--95 from the date of implementation. The closing A of this standard is a prompt appendix.
This standard is proposed and managed by the National Technical Committee for Welding Standardization. The drafting unit of this standard: Harbin Welding Research Institute. The main drafters of this standard: Lin Kegong and Bai Shuyun. 381
1 Scope
Mechanical Industry Standard of the People's Republic of China
Methods for chemical analysis of melted welding fluxesThe flame photometric method for determinationof sodium oxide and potassium oxide contentJB/T 7948.9-1999
Replaces JB/T 7948.9-95
This standard is applicable to the determination of sodium oxide and potassium oxide in melted welding fluxes. Determination range: 0.20%~3.00%. This standard complies with GB/T1467-1978 "General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products". 2 Referenced Standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard is published, the versions shown are valid. All standards will be revised, and parties using this standard should explore the possibility of using the latest versions of the following standards. GB/T1467-1978 General Principles and General Provisions of the Standard for Chemical Analysis Methods of Metallurgical Products 3 Method Summary
This method is based on the use of a special sprayer to introduce the analyzed solution in the form of sol into a burner with a flame of a certain combustible gas (acetylene, propane, gasoline, etc.). The measured element is excited in the flame to produce radiation, which is projected to a phototube or photocell through a filter or monochromator to generate a photocurrent, and then the galvanometer is used to measure its radiation intensity. Under certain conditions, the reading of the galvanometer is proportional to the concentration of the measured element. 4 Reagents
4.1 Hydrofluoric acid (40%).
4.2 Sulfuric acid (1+1).
4.3 Hydrochloric acid (1+1).
4.4 Lead trichloride solution (18%).
4.5 Sodium oxide standard solution: Weigh 0.9430g of sodium chloride (reference reagent) that has been pre-dried at 110℃±2℃ to a constant volume, and dissolve it in an appropriate amount of water. Transfer it to a 500mL volumetric flask, dilute it to the mark with water, and mix it. This solution contains 1.0mg sodium oxide in 1mL. 4.6 Potassium oxide standard solution: Weigh 0.9430g of potassium chloride (reference reagent) that has been pre-dried at 110℃±2℃ to a constant volume, and dissolve it in an appropriate amount of water. Transfer it to a 500mL volumetric flask, dilute it to the mark with water, and mix it. This solution contains 1.0mg potassium oxide in 1mL. 5 Instruments
5.1 Flame photometer or atomic absorption spectrophotometer [Working conditions see Appendix A (Suggested Appendix). 5.2 Liquefied gas cylinder or acetylene cylinder.
5.3 Compressed air or compressed air machine (1.105N/m2 pressure). Approved by the Weijia Machinery Industry Bureau on June 24, 1999 382
Implemented on January 1, 2000
6 Sample
JB/T 7948.9—1999
The sample should pass through a 200-mesh screen. Pre-dry at 105-110℃ for 1 hour, and place in a desiccator to cool to room temperature. 7 Analysis steps
7.1 Determination quantity
Three samples should be weighed for determination during analysis, and the average value should be taken. 7.2 Sample quantity
Weigh 0.1000g of sample.
7.3 Determination
7.3.1 Determination of sodium oxide
7.3.1.1 Place the sample (7.2) in platinum blood, add a small amount of water to moisten it, add 5mL of hydrofluoric acid (4.1) and 10~20 drops of sulfuric acid (4.2), mix, heat to dissolve and evaporate until white smoke is completely emitted, and cool slightly. Add 5mL of hydrochloric acid (4.3) and 10mL of water to the residue, heat to dissolve the salts. Cool.
7.3.1.2 Transfer the solution (7.3.1.1) to a 100mL volumetric flask, add 20mL of aluminum chloride solution (4.4), dilute to the mark with water, and mix.
7.3.1.3 Transfer part of the solution (7.3.1.2) to a glass dish, and measure its radiation intensity using a flame photometer with a wavelength of 589~592nm filter. Find the corresponding amount of sodium oxide from the working curve. 7.3.2 Determination of potassium oxide
7.3.2.1 Operate the sample (7.2) according to the steps in 7.3.1.1. 7.3.2.2 Transfer the solution (7.3.2.1) to a 100mL volumetric flask, dilute to the mark with water, and mix well. 7.3.2.3 Transfer part of the solution (7.3.2.2) to glass III and measure its radiation intensity with a flame photometer with a wavelength of 765~~769nm filter. Find the corresponding amount of potassium oxide from the working curve. 7.4 Drawing of working curve
7.4.1 Drawing of working curve of sodium oxide:
Pipette 0.50mL; 1.00mL; 1.50mL; 2.00mL, 2.50mL; 3.00mL: 3.50mL; 4.00mL of sodium oxide standard solution (4.5), place them in a set of 100mL volumetric flasks, add 5mL hydrochloric acid (4.3) and 20mL aluminum trifluoride solution (4.4), dilute with water to the scale, and mix well. Measure its radiation intensity with a flame photometer with a wavelength of 589~592nm filter. Draw the working curve with the amount of sodium oxide as the horizontal axis and the radiation intensity as the vertical axis.
7.4.2 Drawing of potassium oxide working curve:
Pipette 0.50mL; 1.00mL; 1.50mL; 2.00ml; 2.50mL; 3.00mL, 3.50mL; 4.00mL of potassium oxide standard solution (4.6), respectively placed in a 100mL volumetric flask, add 5mL of hydrochloric acid (4.3), dilute to scale with water, and mix well. Measure its radiation intensity with a flame photometer with a wavelength of 765~769nm filter. Draw the working curve with the amount of potassium oxide as the horizontal axis and the radiation intensity as the vertical axis. 8 Calculation of analysis results
Calculate the percentage of sodium oxide and potassium oxide according to formula (1): Na0 (or K,0) = \ × 100% www.bzxz.net
Wherein: m is the amount of sodium oxide or potassium oxide found on the working curve, 8: mo
9 Allowable difference
is the sample amount, g.
The difference between the results of parallel determinations should not be greater than the allowable difference listed in Table 1. (1)
Sodium oxide or potassium oxide content
0.20~0.40
>0.40~0.80
20.80-~1.50
>1.50~3.00
JB/T 7948.9—1999
Table 1 Allowable difference
Allowable difference
JB/T 7948.9--1999
Appendix A
(Suggested Appendix)
Working conditions for determination of sodium oxide and potassium oxide
A1 The reference working conditions for determination of sodium oxide and potassium oxide using flame photometer are as follows: a) Fuel: acetylene, propane or gasoline, b) Sodium measurement filter: wavelength 589~592nm c) Potassium measurement filter: wavelength 765~~769nm. A2 The reference working conditions for determination of sodium oxide and potassium oxide using flame emission of GFU-201 atomic absorption spectrophotometer are shown in Table A1. Table A1 Working conditions for determination of potassium and sodium by atomic absorption method Yuanhao
Acetyl
Air
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