GB/T 15072.16-1994 Chemical analysis methods for precious metals and their alloys - Determination of copper and manganese in gold alloys
Some standard content:
National Standard of the People's Republic of China
Chemical analysis methods for precious metals and their alloys
Determination of copper and manganese in gold alloys
Gold alloys-Determination of copperand manganese contentswwW.bzxz.Net
Subject content and scope of application
This standard specifies the method for determining the copper and manganese contents in gold alloys. GB/T 15072.1694
This standard is applicable to the determination of the copper and manganese contents of AuAgCuMnGd33.5-3.0-2.5.0.4, AuAgCuGd35-5-0.4, AuNiCu7.51.5. Determination range: Cu1%～6%. Mn2%～~4%. 2 Reference standards
GB1.4 Guidelines for standardization work Provisions for the preparation of chemical analysis methods GB1467 General principles and general provisions for chemical analysis methods for metallurgical products GB7728 General principles for chemical analysis of metallurgical products by flame atomic absorption spectrometry 3 Method summary
The sample is dissolved in mixed acid, silver is separated by silver chloride precipitation, and gold is separated by sulfurous acid reduction. In dilute hydrochloric acid medium, an atomic absorption spectrometer is used with an air flame to measure the absorbance of copper and manganese at wavelengths of 324.7nm and 279.6nm. The copper content and the radium content are obtained by the calibration curve method 4 Reagents
4.1 Hydrochloric acid (o1.19g/mL).
4.2 Sulfurous acid (pl.03g/mL).
4.3 Hydrochloric acid (1-+1).
4.4 Mixed acid: Mix 8 units of hydrochloric acid (4.1) with 1 unit of nitric acid (01.42g/ml) and prepare it immediately. 4.5 Mixed acid: Mix 3 units of hydrochloric acid (4.1) with -unit of nitric acid (pl.42g/mL) and prepare it immediately. 4.6 Copper standard stock solution: Weigh 1.000g of metallic copper, accurate to 0.0001g, into a 250ml beaker, add a little water, and add 5ml of nitric acid (pl.42g/mL). Heat to dissolve, and evaporate to nearly dryness. Add 5ml of hydrochloric acid (4.1) and evaporate to nearly dryness, repeat -= times, dissolve the residue with 20)ml salt (4.3), transfer to a 1.000mL volumetric flask, and dilute to the mark with water. Mix with a spoon. This solution contains 1ng in 1ml. 4.7 Manganese standard stock solution: Weigh 1.000g metallic manganese, accurate to 0.0001g. In a 250ml beaker. Add 20ml salt (4.3), after complete dissolution, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix. This solution contains 1mg manganese per ml. 4.8 Copper standard solution: Take 50.00ml copper standard stock solution, put it into a 1000ml volumetric flask, add 20ml hydrochloric acid (1.3), dilute to scale with this, and mix. This solution contains 50ug copper per ml. 4.9 Manganese standard solution: Take 50.00ml manganese standard stock solution, put it into a 1000ml volumetric flask, add 20ml salt (1.), dilute to scale with water, and mix. This solution contains 50g of manganese in 1ml. Approved by the State Administration of Technical Supervision on May 11, 1994 and implemented on December 1, 1994
5 Instruments
GB/T 15072.16.--94
Atomic absorption spectrometer, with copper and manganese hollow cathode lamps. Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Minimum precision requirement: Measure the absorbance of the highest standard solution 10 times, and the standard deviation should not exceed 1.0% of the average absorbance. Measure the absorbance of the lowest standard solution (not the "zero\standard solution") 10 times, and its standard deviation should not exceed 0.5% of the average absorbance of the highest standard solution.
Characteristic concentration: In a solution consistent with the matrix of the test sample solution, the characteristic concentrations of copper and manganese should not be greater than 0.06 and 0.04 μg/ml, respectively. c
Linearity of calibration curve: Divide the calibration 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 should not be less than 0.7.
See Appendix A (reference) for instrument working conditions. 6 Samples
The samples are processed into crumbs, and finally degreased with acetone, washed, dried, and mixed. 7 Analysis steps
7.1 Samples
Weigh the samples according to Table 1, accurate to 0.0001g. Table 1
Content, %
1. 00~~2. 00
>2.00~4.00
>4. 00~6. 00
2.00~4.00
Carry out two independent determinations and take the average value. 7.2 Blank test
Carry out a blank test with the sample.
7.3 Determination
Sample amount·g
7.3.1 The sample is placed in a 250ml beaker. Add 40mL of mixed acid (4.4) to each of the gold, silver, copper and manganese and gold, silver, copper and vanadium alloy samples; add 40mL of mixed acid (4,5) to the gold, nickel and steel alloy sample. Cover the surface and heat at low temperature until the sample is completely dissolved, and evaporate to near dryness. Add 5nL of hydrochloric acid (4.1) and evaporate to near dryness. Repeat three times. Remove, rinse the surface IIIl and the wall of the cup with about 20ml of water, add 2mL of hydrochloric acid (4.3), 80ml of water, heat to boil, add 10mL of sulfurous acid, and continue to boil slightly until the volume is about 50ml. Remove , cool.
7.3.2 Filter the test solution into a 100ml volumetric flask, rinse the surface III, beaker, filter paper and precipitate four times with water, add 2ml hydrochloric acid (4.1), dilute to the mark with water and mix well.
7.3.3 Transfer 10mL of the test solution to a 100ml volumetric flask, add 2mL of hydrochloric acid (4.1), dilute to the mark with water and mix well. 7.3.4 Use air-acetylene flame to zero the atomic absorption spectrometer at wavelengths of 324.7nm and 279.6nm with water, and measure the absorbance of the test solution.
7.4 Drawing of the calibration curve
7.4.1 Transfer 0.2.00.4.00, 6.00, 8.00.10.00, 12.00mL of the copper standard solution to a 100ml volumetric flask, respectively, 16
GBT 15072.76..94
Add 2ml hydrochloric acid (4.1), dilute to scale with water, and mix. 7.4.2 Transfer 0, 1.002.00, 4.00, 6.00, 8.00.9.00ml of manganese standard solution to 100ml container 1.2ml hydrochloric acid (4.1), dilute to scale with water, and mix. 7.4.3 Under the same conditions as the sample determination, measure the absorbance of the standard solution. Draw a calibration curve with the concentration of the element (copper, manganese) as the horizontal axis and the absorbance (minus the absorbance of the "zero" concentration solution) as the vertical axis. 8 Expression of analysis results
Calculate the percentage of copper and manganese according to the following formula: (cr -- ce) X Va X V2 X 10
(%)
-the element being measured;
where: —-
c-the concentration of the element being measured in the sample solution obtained from the calibration curve, μg/ml.co-the concentration of the element being measured in the blank solution obtained from the calibration curve, ug/ml.;V. Total volume of solution, mL,
V,---the volume of the transferred solution, mL;
V--the dilution volume of the transferred solution, mL
9 Allowable difference
-the mass of the sample, g.
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
Content, %
1. 00~~2. 00
>2. 00~4. 00
>4. 00 ~~ 6. 00
2.00~4.00
Tolerance, %
GB/T 15072.16 94
Appendix A
Instrument working conditions
(reference)
The working conditions of the 28000 original service spectrophotometer are shown in Table A1: Table A1
Yan Ding'er Suo
Additional instructions:
Wavelength nm
Current + mA
This standard was proposed by China Nonferrous Metals Industry Corporation, and was initiated by Kunming Metal Research Institute. This standard was drafted by Kunming Metal Research Institute. The main drafters of this standard are Yang Ju and Su Qingfu118
Spectral passband, m
Current measurement temperature + mm air excitation, ./mi acetylene current excitation, lmin6
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