This standard specifies the determination method of magnesium content in copper and copper alloys. This standard is applicable to the determination of magnesium content in copper and copper alloys. Determination range: 0.015% ~ 1.00%. GB/T 5121.18-1996 Chemical analysis method for copper and copper alloys Determination of magnesium content GB/T5121.18-1996 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis method for copper and copper alloysDetermination of magnesium content1 Scope
This standard specifies the method for determination of magnesium content in copper and copper alloys. This standard is applicable to the determination of magnesium content in copper and copper alloys. Determination range: 0.015% to 1.00%. 2 Reference standards
GB/T 5121- 18 --- 1996
Generation (B 8550.887
The clauses contained in the following standards constitute the clauses 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. GB1.4-88 Standardization work guidelines for the preparation of chemical analysis method standards GB1467-78 General principles and general provisions for chemical analysis method standards for metallurgical products GB7728-87 General principles for flame atomic absorption spectrometry for chemical analysis of metallurgical products 3 Method summary
The sample is dissolved in nitric acid and hydrofluoric acid. In a nitric acid medium, an air-acetylene flame is used at the wavelength of the atomic absorption spectrometer 285, measure the absorbance of magnesium at 2nm. The interference of silicon, aluminum, titanium and beryllium can be eliminated by adding strontium nitrate; other coexisting elements such as copper, nickel, lead and zinc do not interfere with the determination.
4 Reagents
4.1 Hydrofluoric acid (pl.13g/ml.).
4.2 Nitric acid (1+1).
4.3 Boric acid solution (30g/L).
4.4 Strontium nitrate solution (25g/1.).
4.5 Magnesium standard stock solution: weigh 0.1000g pure magnesium and place it in a 150ml beaker, add 10ml nitric acid (4.2), heat to dissolve. Boil to remove nitrogen oxides, and cool. Transfer 1000 mL volumetric flask, dilute to scale with water, and mix. 1mL of this solution contains 100μg magnesium. 4.6 Magnesium standard solution: Pipette 10.00mI magnesium standard stock solution into a 100mL volumetric flask, dilute to scale with water. Mix. 1mL of this solution contains 10μg magnesium.
5 Instruments
Atomic absorption spectrometer with magnesium 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 consistent with the matrix of the measurement solution, the characteristic concentration of magnesium should not be less than ().0)1 ug/ml. 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 "zero" standard solution), and its standard deviation shall not exceed the average absorbance of the highest standard solution. State Administration of Technical Supervision approved on November 4, 1996 282
19970401 implementation
GB/T 5121. 18
Working curve linearity: Divide the working curve into 5 sections according to concentration. 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. For instrument working conditions, see Appendix A (suggested Appendix). 6 Analysis steps
6.1 Test materials
Weigh the sample according to Table 1, accurate to 0.0001g. Table
Magnesium content, %
0. 015~0. 040
0. 040~- 0. 080
0. 080~~0. 25
0. 25--1. 00
Test material quantity.g
Carry out two independent determinations and take the average value. 6.2 Blank testwwW.bzxz.Net
Carry out blank test with the sample at any time.
6.3 Determination
Total volume of test solution, ml
Take the volume of test solution, ml,
6.3.1 Place the test material (6.1) in a 150mL polytetrafluoroethylene beaker, add 8ml nitric acid and 3-~5 drops of fluoric acid, and heat until the test material is completely dissolved. Add 10ml boric acid solution, mix well, and cool. Transfer to a 100mL volumetric flask. When the magnesium content is between 0.015% and 0.040%, add 10 mL of strontium nitrate solution, dilute to the mark with water, and mix. When the magnesium content is greater than 0.040%, dilute the test solution to the mark with water, mix well, and take the test solution into a 100 mL bottle according to Table 1, add 5 mL of nitric acid and 10 mL of strontium nitrate solution, dilute to the mark with water, and mix well. 6.3.2 Using air-acetylene flame, at a wavelength of 285.2nm on the atomic absorption spectrometer, adjust to zero with water and measure the absorbance of the solution simultaneously with the standard solution series. Subtract the absorbance of the blank solution accompanying the sample and find the corresponding magnesium concentration from the working curve. 6.4 Drawing of working curve
6.4.1 Transfer 0, 1.00, 2.00, 3.00, 4.00, 5.00) ml of magnesium standard solution into a 100ml volumetric flask respectively, add 5ml of nitric acid and 10ml of strontium nitrate solution, dilute to the scale with water and mix well. 6.4.2 Using air-acetylene flame, at the wavelength of 285.2nm of the atomic absorption spectrometer, adjust the zero 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 magnesium concentration as the horizontal axis and absorbance as the vertical axis. 7 Expression of analysis results
Calculate the percentage of magnesium according to formula (1):
C.Vo-V, X 106
Mg(%)
Where: - magnesium concentration of the sample solution obtained from the working curve, g/ml: V——total volume of the test wave, mL
V-volume of the diluted aliquot of the test solution, ml.; V——volume of the aliquot of the test solution, mL;
mass of the sample·g.
GB/T5121.181996
The result is expressed to two decimal places. If the magnesium content is less than 0.10%, express it to 3 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. 015~~0. 040
>0.040~0.080
0.0800.25
>0. 25 ~0. 50
>0.50~1.00
GB/T5121.18-1996
Appendix A
(Suggestive Appendix)
Instrument working conditions
The working conditions for determining the magnesium content using Hitachi 508 atomic absorption spectrometer are shown in Table A1. Table A1
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