GB/T 15072.14-1994 Chemical analysis methods for precious metals and their alloys Determination of aluminum content in silver alloys GB/T15072.14-1994 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 aluminium content in silver alloys
Silver alloys --Determination of aluminium content1 Subject content and scope of application
This standard specifies the method for determining the aluminium content in silver alloys. GB/T15072.14--94
This standard applies to the determination of aluminium content in AgCuNiA120-2-1 alloy. Determination range: 0.5%-~1.2%. 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 of 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 a nitric acid medium with a pH of 5.2 to 5.7, aluminium reacts with chrome azure S to form a purple-red complex, and its absorbance is measured at a wavelength of 545nm on a spectrophotometer. Interferences from copper, nickel and associated elements are masked with zinc-ethylenediaminetetraacetic acid. 4 Reagents
4.1 Nitric acid (pl.42g/mL).
4.2 Nitric acid (1+19).
4.3 Zinc-ethylenediaminetetraacetic acid disodium solution: weigh 1.57g of metallic zinc in a 200ml beaker, add 10ml of nitric acid (1+1) to dissolve; weigh 7.44g of ethylenediaminetetraacetic acid disodium to dissolve in 800ml of water, add 10ml of ammonia water (1+1) to mix. Combine the above two solutions, adjust the acidity of the solution to pH 5.3 with nitric acid (1+1) and ammonia water (1+1), dilute to 11 with water, and mix until the ratio of zinc to ethylenediaminetetraacetic acid disodium (mol/1.) in the mixed solution is 1.2 to 1). 4.4 Hexamethylenetetramine solution (400g/L). 4.5 Chrome Azure S solution (1g/L).
4.6 Lead standard stock solution: Weigh 0.1000g of aluminum into a 250mL beaker, add 10mL of sodium hydroxide solution (200g/l). Heat at low temperature to dissolve. After complete dissolution, add nitric acid (1+1) to 100mL of water, add 10mL of excess, cool to room temperature, transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 100ug aluminum in 1ml. 4.7 Aluminum standard solution: Transfer 20.00mL of aluminum standard stock solution into a 500mL volumetric flask, add 5mL of nitric acid (1+1), dilute to scale with water, and mix. This solution contains 4μg aluminum in 1mL. Approved by the State Administration of Technical Supervision on May 11, 1994 108
Implemented on December 1, 1994
5 Instrument
Spectrophotometer.
6 Sample
GB/T 15072.14--94
The sample is processed into crumbs, and finally degreased with ketone, washed, dried and mixed. 7 Analysis steps
7.1 Sample
Weigh about 0.1g of sample to an accuracy of 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 250mL beaker, add 5mL nitric acid (4.1), cover with surface III, heat at low temperature until the sample is completely dissolved, remove, cool to room temperature, rinse the surface blood and the beaker wall with water, transfer to a 100mL volumetric flask, dilute to scale with water, and mix. Transfer 1.50mL of the test solution to a 50mL volumetric flask. wwW.bzxz.Net
7.3.2 Add 5mL nitric acid (4.3), 5mL Zn-EDTA solution, and 5mL hexamethylenetetramine solution to the test solution in sequence. Mix each time a reagent is added. Immediately add 2.00mL chrome blue S solution, mix well, dilute to scale with water, and mix. Let stand for 30 minutes. 7.3.3 Transfer part of the solution into 1cm absorption III, and measure its absorbance at 545nm on the spectrophotometer with the blank sample as reference. Obtain the aluminum content from the working curve. 7.4 Drawing of working curve
7.4.1 Transfer 0.1.00, 2.00, 3.00, 4.00, 5.00mL of aluminum standard solution into 50mL volumetric flasks respectively, and proceed as per 7.3.2.
7.4.2 Transfer part of the solution into 1cm absorption III, and measure its absorbance at 545nm on the spectrophotometer with the blank sample as reference.
Draw the working curve with the aluminum content as the horizontal axis and the absorbance as the vertical axis. 8 Expression of analysis results
Calculate the percentage of aluminum by the following formula:
Where: m,
Al(%) = mi ×V,× 10 6
-The amount of aluminum found from the working curve, ug; V. —-Total volume of test solution, mL;
V.-Volume of test solution taken, mL,
-The mass of the test material, g.
The result should be expressed to two decimal places.
9 Allowable difference
The difference in analysis results between laboratories should not exceed 0.05%. X 100
Additional remarks:
GB/T15072.14-94
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 Kunming Precious Metals Research Institute. The main drafter of this standard is Wang Chongyi
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