GB/T 15072.15-1994 Chemical analysis methods for precious metals and their alloys - Determination of nickel, zinc and manganese in gold, silver and palladium alloys
Some standard content:
National Standard of the People's Republic of China
Chemical analysis methods for precious metals and their alloys
Gold, silver and palladium alloys-Determinationof nickel, zinc and manganese contents1 Subject content and scope of application
This standard specifies the method for the determination of nickel, zinc and manganese contents in gold, silver and palladium alloys. GB/T 15072.15 .94
This standard is applicable to the determination of nickel, zinc and manganese contents in AuCuNiZnMn181.80.7.0.03, AuCuNiZn22-2.5-0.7, AuCuNiZn30-3-1, AuNi-Cr5-1, AuViCr5-2, AgCuNiAl20-2-1, PdAgCuAuPtZn30-14-10-10-1 alloys. Determination range: nickel 1%~5%. Zinc 0.5%~1.5%, manganese 0.01%~0.05%. 2 Reference standards
GB1.4 Standardization Guidelines for the preparation of chemical analysis methods GB1467 General and general provisions of chemical analysis methods for metallurgical products GB7728 General principles for flame atomic absorption spectrometry for chemical analysis of metallurgical products 3 Method summary
The sample is dissolved in hydrochloric acid and nitric acid. Hydrazine hydrate is used to reduce and separate gold, platinum, palladium and part of copper, and silver is separated by silver chloride precipitation. In dilute hydrochloric acid medium, air and acetone fast flame are used to measure the absorbance of nickel, zinc and manganese at wavelengths of 346.2, 213.8 and 279.5nm of the atomic absorption spectrometer, and their contents are obtained by calibration curve method.
4 Reagents
4.1 Hot acid (ol.19g/mL).
4.2 Nitric acid (p.42 g/mL).
4.3 Hydrochloric acid (1--1)
4.4 Hydrazine hydrate (1+9).
4.5 Zinc standard stock solution: Weigh 1.000g of metallic zinc, add 20mL of hydrochloric acid (4.3) to a 250ml beaker, heat to boiling after a violent reaction, remove, cool to room temperature, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix. 1ml of this solution contains 1mg of zinc. 4.6 Manganese standard stock solution: Weigh 1.000g of metallic manganese, add 20mL of hydrochloric acid (4.3) to a 250ml beaker, heat to boiling after a violent reaction, remove, cool to room temperature, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix. This solution mL contains 1 mg manganese, 4.7 nickel, zinc, manganese mixed standard solution: weigh 0.5000g metallic nickel, put it in a 250ml beaker, add 15ml hydrochloric acid (4.1), heat at low temperature until completely dissolved, remove, cool to room temperature, transfer to a 500ml volumetric flask, then add 10.00ml zinc standard stock solution (4.5) and 25.00ml manganese standard stock solution (4.6) to the volumetric flask, dilute to the scale with water, and mix: this solution 1ml contains 1mg nickel, 20ug zinc, 50μg manganese
Approved by the State Bureau of Technical Supervision on 1994-05-11 and implemented on 1994-12-01
5 Instruments
GB/T 15072.15-94
Atomic absorption spectrometer, with nickel, zinc 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: The standard deviation of the absorbance of the highest standard solution measured 10 times should not exceed 1.0% of the average absorbance; the standard deviation of the absorbance of the lowest standard solution (not the "zero" standard solution) measured 10 times 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 nickel, zinc, and manganese should not be greater than 0.6, 0.02, and 0.04 μg/mL, respectively.
Linearity of calibration curve: The calibration curve is divided 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 Test sample
The sample is crushed into crumbs, and finally degreased with acetone, washed, dried, and mixed. 7 Analysis steps
7.1 Test sample
Weigh the sample according to Table 1, accurate to 0.0001g. Table 1
Carry out two independent determinations and take the average value. 7.2 Blank test
Carry out a blank test with the test sample.
7.3 Determination
Content, %
1.00~5.00
0.50～1.50bzxZ.net
0. 01~0. 05
Test sample amount g
7.3.1 Place the test sample in a 250mL beaker, add acid repeatedly according to Table 2, cover with a watch glass, heat at low temperature until the test sample is completely dissolved, and evaporate to nearly dryness. Add 5mL hydrochloric acid (4.1), evaporate to nearly dryness, repeat three times, and remove. Rinse the surface III and the cup wall with about 10mL of water, add 1mL of hydrochloric acid (4.3) and 40mL of water, and stir to dissolve the soluble salts. Table 2
Silver, copper, nickel, aluminum
Palladium, silver, copper, gold, platinum, zinc
Other alloys
Hydrochloric acid (4.1)
Add acid, mL
Nitric acid (1.2)
7.3.2 Add 4mL of hydrazine hydrate dropwise under stirring (silver, copper, nickel, aluminum alloy test solution may not be added). Cover with a watch glass, heat and boil for 30min, remove and cool to room temperature, rinse the surface blood and the cup wall with water, pour the upper clear liquid into a 100mL volumetric flask, rinse the beaker and precipitate with water four times each, and pour the clear liquid into the volumetric flask, add 3mL of hydrochloric acid (4.5), dilute to the scale with water, and mix well. The following is the determination of nickel and manganese according to 7.3.4. 7.3.3 Pipette 5 mL of the test solution (7.3.2) into a 100 mL volumetric flask, add 4 mL of hydrochloric acid (4.3), dilute to the mark with water, and mix. The following 112
Measure zinc according to 7.3.4.
GB/T 15072.15-94
7.3.4 Use air-acetylene flame to zero the atomic absorption spectrometer at wavelengths of 346.2, 213.8, and 279.5 nm with water, and measure the absorbance of the test solution.
7.4 Drawing of calibration curve
7.4.1 Take 0, 1.00, 2.00, 3.00, 4.00, 5.00.6.00ml of the mixed standard solution of nickel, zinc and manganese, put it into a 100ml volumetric flask, add 4mlL hydrochloric acid (4.3), dilute to the scale with water, and mix. 7.4.2 Under the same conditions as the test sample, measure the absorbance of the standard solution. Draw the calibration curve with the concentration of the measured element (nickel, zinc, manganese) as the horizontal axis and the absorbance (minus the absorbance of the zero concentration solution) as the vertical axis (only take the first five points when drawing the calibration curve of zinc). 8 Expression of analysis results
Calculate the percentage of the measured element according to the following formula: (ci co) × V. × V2× 10-6
α(%)
mox Vi
Where: α is the content of the measured element (nickel, zinc, manganese), %; c1-the concentration of the measured element (nickel, zinc, manganese) in the sample solution obtained from the calibration curve, ug/mL: Co is the concentration of the measured element (nickel, zinc, manganese) in the blank solution obtained from the calibration curve, ug/mL; V-total volume of the test solution, m.
V2—the volume of the diluted solution to be transferred, mL;
m. The mass of the sample, g.
The result should be expressed to two decimal places. When it is less than 0.1%, it should be expressed to three decimal places. Allowable difference
The difference between the analysis results between laboratories should not be greater than the allowable difference listed in Table 3. Table 3
1.00-~2.00
>2. 00~3. 00
≥3. 00 ~ 5. 00
0.50~1.50
0. 010 ~~0. 030
≥0.030～0. 050
Allowable difference
GB/T 15072.15—94
Appendix A
Working conditions
(reference)
The working conditions of Z-8000 atomic absorption spectrometer are shown in Table A1: Table A1
Determination elements
Additional instructions:
Wavelength.nm
Lamp current.mA
Spectral passband, nm
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is drafted by Kunming Precious Metals Research Institute. The main drafters of this standard are Su Qingfu, Zhuang Dianxiang and Fang Wei. Observation height, mm
Air flow rate, L/min, .imin5.5
From the date of implementation of this standard, the original Ministry of Metallurgy Standard YB946 (Au-16)-78 "Gold-Nickel Steel Zinc-Manganese Alloy Absorption Spectrophotometry" will be invalid.
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