This standard specifies the method for determining the vanadium content in silver alloys. This standard is applicable to the determination of the vanadium content in AgCuV10-0.2 alloys. Determination range: 0.1% to 0.4%. GB/T 15072.12-1994 Chemical analysis methods for precious metals and their alloys Determination of vanadium content in silver alloys GB/T15072.12-1994 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 vanadium content in silver alloys
Silver alloys--Determination of vanadium contentSubject content and scope of application
This standard specifies the method for determining the vanadium content in silver alloys. GB/T15072.12-94
This standard applies to the determination of vanadium content in AgCuV10-0.2 alloy. Determination range: 0.1%~0.4%. 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 GB7729 General principles for spectrophotometric methods for chemical analysis of metallurgical products 3 Summary of the method
The sample is dissolved in nitric acid. In 2.5 mol/L nitric acid solution, vanadium (V) forms an orange complex with hydrogen peroxide, and its absorbance is measured at a spectrophotometric wavelength of 450nm.
4 Reagents
The reagents and water used in this standard shall not contain fluoride ions. 4.1 Nitric acid (boil to drive out nitrogen dioxide, 1 + 1). 4.2 Hydrogen peroxide solution (1 + 9).
4.3 Vanadium standard stock solution: weigh 0.5000g of metallic vanadium and place it in a 300ml beaker, add 30ml of nitric acid (p1.42g/ml) and heat until completely dissolved. The solution should be yellow (if it is a green low-valent vanadium solution, add concentrated nitric acid and heat to oxidize it to a high-valent yellow solution), cool, transfer to a 500mL volumetric flask, dilute to the mark with water, and mix well. This solution contains 1mg vanadium in 1mL. 4.4 Vanadium standard solution: transfer 2.5mL of vanadium standard stock solution to a 25mL volumetric flask, dilute to the mark with water, and mix well. This solution contains 100μg vanadium in 1mL.
5 Instruments
Spectrophotometer.
6 Sample
The sample is processed into crumbs, and finally degreased with acetone, washed, dried, and mixed. 7 Analysis steps
7.1 Sample
Approved by the State Administration of Technical Supervision on May 11, 1994 104
Implemented on December 1, 1994
GB/T 15072.12
Weigh about 0.1g of sample, accurate to 0.0001g. Perform two independent measurements and take the average value. 7.2 Blank test
Carry out a blank test along with the sample.
7.3 Determination
7.3.1 Place the sample (7.1) in a 50ml beaker, add 5mL nitric acid, cover with a watch glass, heat until the sample is completely dissolved, remove, rinse the watch glass and the beaker wall with water, evaporate until almost dry, add 8mL nitric acid to dissolve the residue, and transfer to a 25ml volumetric flask. 7.3.2 Dilute with water to 20~24mL, mix well, add 0.50mL hydrogen peroxide, dilute with water to the scale, and mix well. 7.3.3 Transfer part of the solution into a 3cm absorbent tube, use the blank sample as a reference, and measure its absorbance at a wavelength of 450nm on a spectrophotometer. Obtain the vanadium content from the working curve. 7.4 Drawing of working curvebZxz.net
7.4.1 Transfer 0, 0.50, 1.00, 2.00, 3.00, 4.00.5.00, 6.00mL of vanadium standard solution to a set of 25mL volumetric flasks, add 8mL of nitric acid, and proceed as per 7.3.2. 7.4.2 Transfer part of the solution into 3cm absorbent tube, use reagent blank as reference, and measure its absorbance at 450nm wavelength on spectrophotometer.
7.4.3 Draw working curve with vanadium content as horizontal axis and absorbance as vertical axis. 8 Expression of analysis results
Calculate the percentage of vanadium by the following formula:
V(%) =3
Where; m.-the amount of vanadium found from the working curve, ug; mi
…the mass of the sample.g.
The results should be expressed to two decimal places
9Permissible difference
The difference between the analysis results of laboratories should not exceed 0.04%. Additional remarks:
This standard is proposed by China Nonferrous Metals Industry Corporation. This standard is drafted by Kunming Precious Metals Research Institute. This standard is drafted by Kunming Precious Metals Research Institute. The main drafter of this standard is Hao Ruilin.
From the date of implementation of this standard, the former Ministry of Metallurgical Industry Standard YB946 (Ag-8)-78 "Chemical Analysis Method of Silver-Copper-Vanadium Alloy" will be invalid. 105
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