This standard specifies the determination of antimony content by potassium iodide photometry. JB/T 7520.4-1994 Chemical analysis method for phosphorus copper solder Determination of antimony content by potassium iodide photometry JB/T7520.4-1994 Standard download decompression password: www.bzxz.net

Mechanical Industry Standard of the People's Republic of China
Chemical Analysis Method of Phosphorus Copper Brazing Material
Determination of Antimony by Potassium Iodide Photometry
Subject Content and Scope of Application
This standard specifies the determination of antimony by potassium iodide photometry. This standard is applicable to the determination of antimony in phosphorus steel brazing material, with a determination range of 1.50%~～2.50%. 2'Method Summary
JB/T7520.4—94
After the sample is dissolved in mixed acid, sulfur gland is added to mask a large amount of copper, potassium iodide is added to the acidic solution, and antimony II and hardness I form a yellow complex (SbI,), which is used for photometric determination. 3 Reagents
3.1 Mixed acid: Weigh 20g of tartaric acid and dissolve it in 30mL of water, add 50mL of nitric acid (pl.42g/mL), and dilute with water to 100mL3.2 Sulfuric acid (1+1).
3.3 Urea.
3.4 ​​Sulfur gland solution (10%).
3.5 Potassium iodide solution: Weigh 112g potassium iodide and 20g ascorbic acid and dissolve them in appropriate amount of water, dilute to 1000mL with water, and store in a brown bottle.
3.6 Antimony standard solution: Weigh 0.1000g metal antimony (purity is above 99.99%) and place it in a 150mL conical flask, add 25mL sulfuric acid, heat to dissolve, cool, add water to 100mL, mix, cool, transfer to a 500mL volumetric flask, dilute to the mark with sulfuric acid (13), and mix. This solution contains 0.20mg antimony in 1mL.
3.7 Antimony standard solution: Pipette 25.00ml. Antimony standard solution (2.6) and place it in a 100mL volumetric flask, dilute to the mark with sulfuric acid (1+3), and mix. 1 mL of this solution contains 0.05 mg of antimony. 3.8 Copper metal (purity of 99.99% or more). 4 Analysis steps
4.1 Sample amount
Weigh 0.1000 g of sample.
4.2 Blank test
Weigh the same amount of cadmium metal (3.8) as the sample as the reagent blank. 4.3 Determination
4.3.1 Place the sample (4.1) in a 100 mL dual-purpose bottle, add 10 mL of mixed acid (3.1), heat to dissolve, and after the sample is completely dissolved, rinse the bottle wall with water, boil for about 30 minutes, cool slightly, add a little urea (3.3) to decompose the chlorine oxide, cool, and dilute with water to the scale + mix.
4.3.2 Accurately pipette 10mL of solution into a 50mL volumetric flask, add 5tmL of thiourea solution (Article 3.4) and 9mL of sulfuric acid (Article 3.2). Mix well. Cool with running water, add 25mL of potassium iodide solution (Article 3.5), dilute to scale with water, and mix well. Approved by the Ministry of Machinery Industry of the People's Republic of China on 1994-12-09 322
1995-10-01 Reality
JB/T 7520.4--94
4.3.3 Pipette part of the solution into a 3cm colorimetric tube, use the reagent blank solution (Article 4.2) as the reference solution, and measure its absorbance at a wavelength of 410nm on a spectrophotometer. Find the corresponding antimony amount from the working curve. 4.4 Drawing of working curve
Take six portions of 10.00mL reagent blank solution (4.2) and place them in 50mL volumetric flasks respectively. Add 0, 1.00, 2.00, 3.00, 4.00, 5.00mL antimony standard solution (3.7), 5mL thiourea solution (3.4) and 9ml sulfuric acid (3.2) in turn. Cool, add 25mL potassium iodide solution (3.5), dilute to scale with water, and mix. The following is done according to 4.3.3, using 0ml as reference solution and measuring absorbance. Draw the working curve with antimony content as the horizontal axis and absorbance as the vertical axis. 5 Calculation of analysis resultsbZxz.net
Calculate the percentage of antimony according to the following formula:
miV.×10-3
Sb(%)-
Wherein: m is the amount of antimony found from the working curve, ng: V,-total volume of the sample solution, mL;
Vi-—volume of the sample solution taken, mL; m.-weighed amount, g.
6 Allowable difference
The difference in the analysis results should not be greater than the allowable difference listed in Table 1. Table 1
1.50~2.50
Additional instructions:
This standard was proposed by Harbin Welding Research Institute of the Ministry of Machinery Industry. This standard was drafted by Harbin Welding Research Institute. The main drafters of this standard are Bai Shuyun, Lin Kegong and Zeng Laimei. Allowable difference
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