This standard specifies the determination method of mercury content in gold alloys. This standard is applicable to the determination of mercury content in gold alloys. GB/T 15249.5-1994 Chemical analysis method for gold alloys - Determination of mercury content by cold atomic absorption spectrometry GB/T15249.5-1994 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Crude Gold-Determination of mercury content--Cold atomic absorption spectrometric method
Crude Gold-Determination of mercury content--Cold atomic absorption spectrometric method1 Subject content and scope of application
This standard specifies the method for determining the mercury content in crude gold. This standard is applicable to the determination of mercury content in crude gold. Determination range: 0.005%~0.05%. 2 Reference standards
CB1, 1 Guidelines for standardization work Rules for the preparation of chemical analysis method standards GB1467: General principles and general provisions for chemical analysis method standards for metallurgical products 3 Origin of the method
GB/T15249.5-94
Weigh a certain weight of the crude gold sample to be tested and decompose it with dilute nitric acid and hydrochloric acid. Filter out the silver chloride precipitate to separate the silver, mask the gold with potassium thiocholate, reduce the mercury with dichloride in a strong alkaline medium, and perform cold atomic absorption spectrometry of mercury at a wavelength of 253.7nm.
4 Reagents
4. 1 Hydrochloric acid (pl.19 g/mL), high-grade purity. 4.2 Nitric acid (pl.42g/ml,), high-grade purity. 4.3 Potassium dichromate solution (10 g/L).
4.4 Potassium thiocholate solution (100 g/L).
4.5 Zinc acetate solution (50g/L).
4.6 Tin fluoride solution [100g/L, 10% (V/V) hydrochloric acid medium]. 4.7
Sodium hydroxide solution (100g/L).
4. 8 Absorption solution (10 g/L KMnO,-1. 8 mol/L H,SO,). 4. 9 Standard mercury storage solution: weigh 0. 1354 g mercuric dichloride and dissolve it in a small amount of water, add 50 mL nitric acid (4.2) and 10 mL potassium dichromate solution (4.3), and dilute to 1 000 mL with water. This solution contains 100 g/mL mercury (the solution should be used within five months). 4.10 Standard mercury solution
4. 10. 1 Pipette 10. 00 mL of standard mercury storage solution (4. 9) into a 100 mL volumetric flask, add 5 mL nitric acid (4.2) and 1 mL potassium dichromate solution (4.3), and dilute to 1 000 mL with water. This solution contains 10 g/L mercury (the solution should be used within two months). 4.10.2 Pipette 1.00 mL of the standard mercury solution (4.10.1) into a 100 mL volumetric flask, add 1 mL of potassium dichromate solution (4.3), and dilute to volume with water. This solution contains 0.1 g/mL (the solution should be prepared). Approved by the State Administration of Technical Supervision on October 7, 1994: implemented on August 1, 1995
5 Instrument
Cold atomic absorption measurement of mercury.
6 Analysis steps
6.1 Test materials
GB/T 15249.5-94
Weigh the powdered gold test material according to Table 1 to an accuracy of 0.0001 g. Table 1
Mercury content, %
0, 005~0. 01
>0. 01--0. 02
>0. 02~-0. 05
6. 2 Blank test
Sample amount
A blank test is performed together with the sample, and the average value of three blank tests is taken. 6. 3 Determination
Dilution volume, ml
Volume of test solution, mL
6. 3. 1 Place the sample (6. 1) in a 100 mL beaker, add 10 mL of water and 3 mL of nitric acid (4.2), dissolve under slight boiling for 5 min, add 10 mL of hydrochloric acid (4. 1) to dissolve and evaporate at low temperature until nearly dry, add 5 mL of hydrochloric acid (4. 1) and evaporate again until nearly dry. 6.3.2 Add about 50 mL of water and boil for 1~2 min. After the solution cools to room temperature, filter it into a 100 mL volumetric flask with medium-speed filter paper. Wash the filter paper and precipitate with water for 3~5 times, add the washed solution into the filtrate, and make up to volume with water. 6-3.3 Divide the test solution (6.3.2) into a 50 mL volumetric flask according to Table 1, add 1 mL of hydrochloric acid (4.1), make up to volume with water, take 1.00 ml of the sample solution (6.3.3) into a 15 mL reduction bottle, add water to 2 ml, 6.3.4 add 1.0 mL of potassium thiouracil solution (4.4), 0.4 mL of zinc acetate solution (4.5), and 1.0 mL of tin difluoride solution (4.6) (shake well after adding each reagent). Slowly add 2.2 mL of sodium hydroxide solution (4.7) along the bottle wall (do not shake!), quickly cover the reduction bottle with a ground stopper, bubble and record the maximum display value (the instrument should be zeroed before each measurement). Then, rotate the three-way piston to connect the residual mercury absorption device and absorb the residual powder in the residual absorption liquid (4.8).
6.4 Drawing of working curve
6.4:1 Weigh 0, 0.20, 0.40, 0.60, 0.80, 1.00 mL of mercury standard solution (4.10.2) in a 15 ml reduction bottle, add water to 2 ml, and proceed as in 6.3.4 (the reagent blank should be measured three times and the average value should be taken). 6.4.2 Use the amount of mercury as the horizontal axis and the display value minus the reagent blank as the vertical axis to draw the working curve. Calculation and expression of analysis resultsbzxz.net
The percentage content is calculated as follows:
Hg(%) =m × 50 × 100 × 10-5Vx0.2
wherein m-
the amount of mercury found from the working curve, g;
the volume of the test solution (6.3.2) taken, mL.
8 Allowable difference
GB/T 15249.5-94
The difference in the analysis results between the experimental spaces should not be greater than the allowable difference listed in Table 2. Table 2
0.0050:010
>0,010~0.025
>0.025~0.050
Additional Notes:
This standard was jointly proposed by the People's Bank of China Printing Corporation and the State Gold Administration. This standard was drafted by China Gold and Silver Smelter and Changchun Gold Research Institute. This standard was drafted by Beijing Research Institute of Mining and Metallurgy. The main drafter of this standard is Sun Linggao,
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