This standard specifies the method for determining the cobalt content in copper and copper alloys. This standard is applicable to the determination of the cobalt content in copper and copper alloys. Determination range: 0.020% to 1.00%. GB/T 5121.15-1996 Chemical analysis method for copper and copper alloys Determination of cobalt content GB/T5121.15-1996 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-Determination of cobalt content Copper and copper alloys-Determination of cobalt content This standard specifies the method for determining the cobalt content in copper and copper alloys. This standard is applicable to the determination of the cobalt content in copper and copper alloys. Determination range: 0.020%~1.00%. Referenced standards
GB/T5121.15-1996
Replacement (B 8550.7-87
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 the parties using this standard should explore the possibility of using the latest versions of the following standards. GB1.4---88 Guidelines for standardization work Chemical analysis method standard preparation regulations GB1467-78 General principles and general provisions for chemical analysis method standards for metallurgical products GB7728-87 General principles for chemical analysis of metallurgical products by flame atomic absorption spectrometry 3 Method summary
The sample is dissolved in nitric acid and hydrofluoric acid. In the nitric acid medium, the absorbance of cobalt is measured at a wavelength of 240.7nm using an air-acetylene flame on an atomic absorption spectrometer. The interference of the matrix copper, nickel and manganese is eliminated by adding corresponding amounts of copper, nickel and manganese when preparing the standard series of solutions; other coexisting elements such as lead, zinc and iron do not interfere with the determination. 4 Reagents
4.1 Pure copper.
4.2 Pure nickel (Co<0.001%).
4.3 Pure manganese.
4.4 Hydrofluoric acid (p 1.13g/mL).
4.5 Nitric acid (1+1).
4.6 Boric acid solution (30g/l.).
4.7 Cobalt standard stock solution: Weigh 1.0000g of pure cobalt and place it in a 150ml beaker, add 10mL of nitric acid (4.5), heat to dissolve, boil to remove nitrogen oxides, and cool. Transfer to a 1000ml volumetric flask, dilute to the mark with water, and mix well. This solution contains 1mg of cobalt in 1ml. 4.8 Cobalt standard solution: Transfer 20.00ml of cobalt standard stock solution to a In a 100mL volumetric flask, dilute to the mark with water and mix. This solution contains 200μg of cobalt in 1mL.
5 Instruments
Atomic absorption spectrometer, with cobalt hollow cathode lamp. Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Sensitivity: In a solution that is consistent with the matrix of the measurement solution, the characteristic concentration of cobalt should not exceed 0.088μg/ml. Approved by the State Administration of Technical Supervision on November 4, 1996 272
Implementation on April 1, 1997
GB/T 5121. 15
Precision: Measure the absorbance 10 times with the highest concentration standard solution, and its standard deviation shall not exceed 1.0 of the average absorbance: Measure the absorbance 10 times with the lowest concentration standard solution (not the "qin" standard solution), and its standard deviation shall not exceed 0.5% of the average absorbance of the high standard solution.
Linearity of working curve: Divide the working curve into five sections according to concentration, and the ratio of the absorbance difference of the highest section to the absorbance difference of the lowest section shall not be less than 0.85.
See Appendix A (Suggested Appendix) for instrument operating conditions. 6 Analysis steps
6.1 Test materials
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Cobalt content %
0.020~-0. 10
0. 10~0. 40
20. 40~1, 00www.bzxz.net
Sample amount g
Carry out two independent determinations and take the average value. 6.2 Blank test
Carry out a blank test with the sample.
6.3 Determination
Total volume of test solution, ml.
Take the volume of test solution, ni
6.3.1 Place the sample (6.1) in a 150ml polytetrafluoroethylene beaker, add 15ml nitric acid and 2 drops of hydrofluoric acid, and heat until the sample is completely dissolved. Add 10 mL of boric acid solution, mix well, and cool. 6.3.2 Transfer the solution into a 100ml volumetric flask, dilute to the mark with water, and mix well. 6.3.3 When the amount of cobalt is greater than 0.10%, transfer the solution (6.3.2) according to Table 1 into a 100ml volumetric flask, add 5ml nitric acid, dilute to scale with water, and mix.
6.3.4 Using air-acetylene flame, measure the absorbance of the test solution at a wavelength of 240.7nm on the atomic absorption spectrometer, and adjust to zero with water at the same time as the standard solution series. Subtract the absorbance of the blank solution accompanying the sample, and find the corresponding cobalt concentration from the working curve. 6.4 Drawing of the working curve
6.4.1 Weigh 10 times the amount of copper and nickel in the sample (6.1) (1.25 pure saw for analysis of BMn3-12) into the same 300ml beaker, add 80ml nitric acid, heat until completely dissolved, boil to remove nitrogen oxides, transfer to 200ml of the flask, dilute to scale with water, and mix. 6.4.2 Take 0.1.00, 2.00.3.00, 4.00.5.00ml of cobalt standard solution and place them in 100ml volumetric flasks. Add solution according to cobalt content (6.4.1): when the cobalt content is 0.020%~0.10%, add 20.0ml; when the cobalt content is greater than 0.10%~0.40%, add 5.0ml; when the cobalt content is greater than 0.40%~1.00%, add 2.0ml. Then add 5ml of nitric acid, dilute with water to the scale and mix. 6.4.3 Under the same conditions as the test solution, measure the absorbance of the standard solution, subtract the absorbance of the standard solution with the same concentration as the sample solution, and draw a working curve with the cobalt concentration as the horizontal axis and the absorbance as the vertical axis. 7 Expression of analysis results
Calculate the cobalt content according to formula (1):
Co(%) = c. V. .V, × 10-
Wherein: — Cobalt concentration of the sample solution obtained from the self-made curve, μg/ml; × 100
V.-Total volume of the test solution, mL
GB/T 5121. 15-1996
V,---Volume of the diluted test solution, mLV,-Volume of the test solution, ml;
mo—Mass of the sample·g.
The result should be expressed to two decimal places. If the cobalt content is less than 0.10%, it should be expressed to three decimal places. 8 Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0. 020-~0.040
>0.040~0.080
>0.080~0.20
>0.20~0. 50
>0. 501. 00
GB/T5121.15
Appendix A
(Suggested Appendix)
Instrument Working Conditions
The working conditions for measuring the drilling amount using Yueli 508 atomic absorption spectrometer are shown in Table A1. Table A1
Spectral passband
Observation height
Air flow address
Flying alkene flow low
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