GB/T 15072.20-1994 Chemical analysis methods for precious metals and their alloys - Determination of zirconium content in gold alloys

This standard specifies the determination method of zirconium content in gold alloys. This standard is applicable to the determination of zirconium content in AuNiFeZr9-2-0.3 AuNiFeZr5-1.5-0.3 alloys. Determination range: 0.1% to 0.5%. GB/T 15072.20-1994 Chemical analysis methods for precious metals and their alloys Determination of zirconium content in gold alloys GB/T15072.20-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Chemical analysis methods for precious metals and their alloys
Determination of zirconium content in gold alloys
Gold alloys --Determination of zirconium content1 Subject content and scope of application
This standard specifies the method for determining zirconium content in gold alloys. GB/T 15072.20 - 94
This standard applies to: Determination of zirconium content in AuNiFeZr9-2-0.3 and AuNiFeZr5-1.5-0.3 alloys. Determination range: 0.1% 0.5%.
2 Reference standards
GB1.1 Guidelines for standardization work Provisions for the preparation of chemical analysis methods GB1167 General principles and general provisions for chemical analysis methods for metallurgical products GB7729 General principles for chemical analysis methods for metallurgical products 3 Method summary
The sample is dissolved in mixed acid. Zirconium (W) and azobenzene form a purple complex in nitric acid medium. The absorbance is measured at a wavelength of 666nm on a spectrophotometer.
4 Reagents
4.1 Nitric acid (pl.42 g/ml).
4.2 Mixed acid: Mix 1 unit volume of nitric acid (4.1) with 1 unit volume of hydrochloric acid (pl.19g/ml). Prepare it before use. 4.3 Urea solution (100g/L).
4.4 Azobenzene solution (4g/L.).
4.5 Standard stock solution of zirconium.
4.5.1 Preparation: Weigh 3.532g zirconyl chloride (Zr0C·8HO), place in a 250ml beaker, dissolve in 50ml hydrochloric acid (1+1). Transfer to a 200ml volumetric flask, dilute to scale with water, and mix. This solution contains 5mg zirconium per ml. 4.5.2 Standardization: Transfer 10.00ml zirconium standard stock solution, place in a 400ml beaker, add 40ml hydrochloric acid (p1.19g/ml), 100ml water, and heat to near boiling. Add 50 ml of mandelic acid solution (150 g/l) under stirring, stir thoroughly until precipitate is formed, keep warm at 80-90°C for 0.5 h, let stand for more than 4 h, filter slowly with filter paper, and wash 7-8 times with hot washing liquid (20 g of mandelic acid and 20 ml of hydrochloric acid (pl.19 g/ml) per liter of solution). Put the precipitate and filter paper into a porcelain pot, incinerate it in a high-temperature furnace after incineration, and burn it at 1000°C for 1 h. Take out the glass, cool it slightly, put it into a desiccator, and weigh it after cooling it to room temperature. Take three copies for parallel calibration. The range should not be greater than 1.0 mg. Take the average value and calculate the actual concentration according to formula (1):
Approved by the State Administration of Technical Supervision on May 11, 1994 and implemented on December 1, 1994
GB/T 15072.20-94
(m2 - ml) × 0.740 3
Wherein: C---actual concentration of zirconium standard storage solution, mg/mL; m,---snail weight, g;
m2——weight of added precipitate·g;
V--volume of zirconium solution taken during calibration, mL; 0.7403--coefficient of zirconium dioxide converted to zirconium. (1
4.6 Zirconium standard solution: Pipette 10.00ml. Zirconium standard storage solution, place in a 200ml volumetric flask. Add 40ml nitric acid (1+1). Dilute to scale with water and mix. Take 1 0.00mL, put it in a 250mL volumetric flask, add 50mL nitric acid (1+1), dilute to the scale with water, and mix well. 1mL of this solution contains 10μg zirconium. 5 InstrumentbZxz.net
Spectrophotometer.
6 Sample
The sample is processed into chips. If necessary, wash with acetone to remove oil stains, wash, dry, and mix well. 7 Analysis steps
7.1 Sample
Weigh 0.1g of sample, accurate to 0.0001g. Perform: -. measurements independently and take the average value. 7.2 Empty self-test||t t||Perform a blank test with the sample.
7.3 Determination
7.3.1 Place the sample in a 100mlL beaker, add 10mL of mixed acid, and cover with surface III. Heat at low temperature until the sample is completely dissolved. And evaporate to 1~~2mL. Add 10nL of nitric acid, boil for 2min, cool to room temperature, and transfer to a 100mL volumetric flask. Dilute to the scale with water and mix well. 7.3.2 Transfer 10.00ml of solution and place it in a 100mL volumetric flask. Add 45ml of nitric acid and 5ml of urea solution, and wash the bottle with water. Shake until no small bubbles are generated. Add 5.0mL of azobis solution and mix. After cooling to room temperature, dilute to scale with water. Mix. 7.3.3 Transfer part of the test solution into a 1cm absorbent tube, use the air accompanying the sample as a reference, and measure its absorbance at a wavelength of 666nm on a spectrophotometer. Find the lead content from the curve. 7.4 Drawing of working curve
7.4.1 Transfer 0.0.50, 1.00, 2.00, 3.00, 4.00, 5.00ml of zirconium standard solution and place them in 100ml volumetric flasks respectively. Add 45ml of nitric acid and 5ml of urea solution, wash the bottle wall with water, shake until no small bubbles are generated, add 5mL of azobis solution and mix. After cooling to room temperature, dilute to scale with water and mix. 7.4.2 Pipette part of the solution into 1 cm absorbent tube, and measure its absorbance at 666 nm using the reagent blank as reference. Draw a working curve with zirconium content as the horizontal axis and absorbance as the vertical axis. 8 Expression of analysis results
: Calculate the percentage of zirconium according to formula (2):
Zr(%) m×10
Where; m.-the zirconium content obtained from the working curve·ug; —the mass of the sample·…,
V. -—volume of sample solution, ml
V. Volume of test solution, ml.
Express the analysis results to two decimal places:
9 Allowable difference
GB/T 15072.20-94
The difference in analysis results between laboratories should not be greater than the allowable difference listed in the following table. Zirconium base
0. 10 ~0. 25
>0.25~0.50
Additional remarks:
This standard was proposed by China Nonferrous Metals Industry Corporation. This standard was drafted by Kunming Precious Metals Research Institute. This standard was drafted by the 62nd Research Institute of the Ministry of Aerospace Industry. The main drafters of this standard are Huang Shumao and Jiang Xiuyu.
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