This standard specifies the determination method of tin content in copper and copper alloys. This standard is applicable to the determination method of tin content in copper and copper alloys, and the determination range is: 0.000 50% ~ 0.004 0%. GB/T 5121.6-1996 Chemical analysis method for copper and copper alloys Determination of tin content GB/T5121.6-1996 Standard download decompression password: www.bzxz.net

1 Scope
National Standard of the People's Republic of China
Chemical analysis method for copper and copper alloys--Deternization of bismuth content This standard specifies the method for determination of bismuth content in copper and copper alloys. GB/T 5121.6--1996
代赞GB5121.685
3 5122. 1885
GB 6520.3 86
GB 8002. 11
GB8550.87
This standard applies to the determination of bismuth content in copper and copper alloys, with a determination range of 0.00050% to 0.0040%. 2 Referenced standards
The provisions contained in the following standards constitute the provisions of this standard through reference in this standard. When this standard was published, the versions shown were valid. All standards are subject to revision. Parties using this standard should explore the possibility of using the latest version of the following standards. GB1.4-88 Standardization work guidelines for chemical analysis method standards GB1467-78 General principles and general provisions for chemical analysis methods for metallurgical products GB7728-87 General principles for chemical analysis of metallurgical products by flame atomic absorption spectrometry 3 Method summary
Samples without tin and silicon are dissolved in nitric acid; samples containing tin and silicon are dissolved in mixed acid. Bismuth is enriched by co-precipitation with manganese dioxide. After the precipitate is dissolved in hydrochloric acid, the absorbance of bismuth is measured at a wavelength of 223.1nm using an air-acetylene flame on an atomic absorption spectrometer. 4 Reagents
4.1 Hydrogen peroxide (30%).
4.2 Ammonia water (p1.90 g/mL).
4.3 Nitric acid (1+1).
4.4 Hydrochloric acid (1+1).
4.5 Nitric acid (2+98).
4.6 Mixed acid: Mix nitric acid (pl.42g/mL), water, and hydrofluoric acid (p1.13g/mL) in a plastic cup 4 at a volume ratio of (49+49+2). 4.7 Manganese nitrate solution: Mix 1 unit volume of manganese nitrate (50%) with 4 unit volumes of water. 4.8 Potassium permanganate solution (10g/L).
4.9 Bismuth standard solution: Weigh 0.1000g of pure bismuth into a 200ml. beaker, add 20mL of nitric acid (p1.42g/ml.) into a 1000mL volumetric flask, and mix well. This solution contains 0.1mg bismuth in 1mL. 5 Instruments
Source electron absorption spectrometer, with bismuth hollow cathode lamp. Under the best working conditions of the instrument, those that can meet the following indicators can be used. Characteristic concentration: In a solution that is consistent with the matrix of the measurement solution, the characteristic concentration of bismuth should not be greater than 0.12g/ml. Precision: The standard deviation of the absorbance measured 10 times with the highest concentration standard solution should not exceed 1.0% of the average absorbance. The standard deviation of the absorbance measured 10 times with the lowest concentration standard solution (not the "zero" standard solution) should not exceed 0.5% of the average absorbance of the highest concentration standard solution.
GB/T 5121.6 1996
Working curve linearity: Divide the working curve into five sections according to the concentration. The ratio of the absorbance difference of the highest section to the absorbance difference of the lowest section should not be less than 0.8.
See Appendix A (Appendix to the reference) for instrument working conditions. 6 Analysis steps
6.1 Test material
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Bismuth content,
0. 000 50~0. 001 0
>0. 001 0~-0. 004
Carry out two independent determinations. Take the average value. 6.2 Blank test
Carry out a blank test with the sample.
6.3 Determination
Test material volume
Nitric acid (.3).ml
6.3.1 Place the test material (6.1) in a 300mL beaker, add nitric acid (4.3) or mixed acid according to Table 1, cover with Table III, heat to dissolve the test material, boil to remove nitrogen oxides, wash Table III and the beaker wall with water, and dilute to a volume of about 50mL. When the sample contains silicon and tin, dissolve the sample in a polytetrafluoroethylene beaker with mixed acid.
6.3.2 Neutralize with ammonia water until turbidity appears and does not disappear after stirring, then add nitric acid (4.3) dropwise until the precipitate is just dissolved, add 10ml of manganese nitrate solution after 10ml.
6.3.3 Heat the solution to 60~80℃, add 10ml of potassium permanganate solution dropwise while stirring, continue stirring for 1.5min, boil slightly for 3~5min, and let stand for 3min.
6.3.4 Filter with medium-speed quantitative filter paper, wash the beaker and precipitate with hot nitric acid (4.5) 2~3 times, retain the precipitate and filter paper. Transfer the filtrate to the original beaker. Heat to 60~~80℃, add 10ml of potassium permanganate solution dropwise while stirring, continue stirring for 1.5min, boil slightly for 3~5nin. Let stand for 3min. Filter with the reserved filter paper, wash the beaker and precipitate 3-4 times with hot nitric acid (4.5) 6.3.5 Dissolve the precipitate in the original beaker with 10 ml hot nitric acid containing 3 mL hydrogen peroxide, and wash 3-4 times. 6.3.6 Boil the solution to remove all hydrogen peroxide and evaporate it to about 10 ml, wash Table III and the wall of the beaker with water, and cool it. Transfer it to a 25 ml volumetric flask, dilute it to the scale with water, and mix it well.
6.3.7 Use air-acetylene flame to zero the atomic absorption spectrometer at a wavelength of 223.1 nm with water, and measure the absorbance of the solution when compared with the standard solution series, and find the corresponding bismuth concentration from the working curve. 6.4 Drawing of working curve
6.4.1 Pipette 0.1.00, 2.00, 3.00, 4.00, 5.00 ml of standard solution into 100 ml of sample, add 40 ml of acid to each, dilute to the mark with water and mix well.
6.4.2 Using air-acetylene flame, at the wavelength of 223.1nn of the atomic absorption spectrometer, adjust the zero value with water. Measure the absorbance of the solution, subtract the absorbance of the "zero" concentration solution in the standard solution series, and draw a working curve with the concentration of bismuth as the horizontal axis and the absorbance as the vertical axis. 7 Expression of analysis results
Calculate the percentage of bismuth according to formula (1):
Bi(%) -- (c1- c) +V× 10**
GB/T5121.6—1996
Where: C——the concentration of bismuth in the test solution obtained from the working curve, μg/mL; co——the concentration of bismuth in the blank solution of the sample obtained from the working curve, μg/mL; volume of the test solution, mL,
m. --the mass of the sample·g.
The obtained result is expressed to 4 decimal places. If the bismuth content is less than 0.0010%, express it to 5 decimal places. 8 Allowable difference
The difference between the analysis results of laboratories shall not be greater than the allowable difference listed in Table 2. Table 2
Bismuth content
0. 000 50~0. 001 0
>0.0010~0.0040www.bzxz.net
GB/T5121.6-1996
Appendix A
(Suggestive appendix)
Instrument working conditions
The working conditions for determining the bismuth content using a WFX-1B atomic absorption spectrometer are shown in Table A1. Table A1
Lamp current
Spectral passband
Observation height
Air flow
Acetylene flow
Background subtraction
Use an atmospheric lamp
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