This standard specifies the polarographic determination of tin content. This standard is applicable to the determination of tin content in ferromolybdenum. Determination range: 0.005%~0.100%. GB/T 5059.4-1988 Chemical analysis method for ferromolybdenum Polarographic determination of tin content GB/T5059.4-1988 Standard download decompression password: www.bzxz.net

National Standard of the People's Republic of China
Methods far chemical analysis of ferromolybdenum www.bzxz.net
Polarographic method for the determination of tin content
Methods far chemical analysis of ferromolybdenum
Polarographic method for the determination of tin content 1 Subject content and scope of application
This standard specifies the polarographic method for the determination of tin content in ferromolybdenum. Determination range: 0.005%~0.100% 2 Method summary
UDC 669. 15'28
GB 5059. 4 88
Generation GB5059.4—85
The sample was dissolved in nitric acid, treated with sulfuric acid to emit white smoke, EDTA was used to eliminate the influence of iron and, at pH 8, sulfuric acid was used as a carrier to precipitate tetravalent tin, nitrogen, hydrogen or hydrogen was used to deoxygenate in a 2~3mol/L hydrochloric acid base solution, and polarographic analysis of tin was performed under alternating current.
3 Reagents
3. I Nitric acid (I+1).
3.2 Hydrochloric acid (1+1), high-grade purity.
3.3 Sulfuric acid (1+1), high-grade purity.
3.4 ​​Sulfuric acid (3.5mol/L).
3.5 Ammonium hydroxide (p0.90 g/mL).
3.6 Sodium hydroxide solution (0.05mol/L). 3.7 EDTA (sodium ethylenediaminetetraacetate dihydrate) solution (100 mg/mL). Beryllium sulfate solution (12 mg/mL).
3.9 Washing solution: Pipette 30 mL of EDTA into solution (3.7), add 13 mL of ammonium hydroxide (3.5), dilute to 600 mL with water, and mix. 3.10 Phenol red solution: Weigh 0.1 B of phenol red, dissolve in 50 mL of water, add 5.7 mL of sodium hydroxide bath (3.6), dilute to 100 mL with water, and mix.
3.11 Tin standard solution
3.11.1 Weigh 0.1000g (purity above 99.9%), place in a 200mL beaker, add 20mL sulfuric acid (p1.84g/mL), heat to dissolve, cool, transfer the solution into a 1000mL volumetric flask with sulfuric acid (3.4), dilute to scale with the same sulfuric acid, and mix. This solution contains 0.1 mg tin per 1mlL.
3.11.2 Transfer 100.00mL of tin standard solution (3.11.1), place in a 1000mL volumetric flask, dilute to scale with sulfuric acid (3,4), and mix. This solution contains 0.01 mg tin per 1mL.
3.12 Nitrogen, fluorine or hydrogen: does not contain oxygen. Approved by the Ministry of Metallurgical Industry of the People's Republic of China on September 8, 198B, and implemented on January 1, 1990
4 Instruments
Polargraph.
5 Sample
The sample should pass through a 0.125mm sieve.
6 Analysis steps
6.1 Sample quantity
Weigh the sample according to Table 1;
Tin quantity, %
0. 005 ~ 0. 010
>0. 010~-0. 100
6.2 Blank test
Carry out a blank test together with the sample.
6.3 Determination
GB 5059. 4-88
Sample quantity
6.3.1 Place the sample (6.1) in a 250mL beaker, add 20mL nitric acid (3.1) and 5mL sulfuric acid (3.3), heat to decompose the sample and evaporate until white sulfuric acid smoke appears, dissolve the salt in 30mL water, add 30mL EDTA solution (3.7) and 8mL beryllium sulfate solution (3,8), boil for 3min, add 2~3 drops of phenol red solution, adjust the solution to red with 1~2mL excess with ammonium hydroxide, boil for 3min, and cool. Filter with medium density filter paper, rinse the beaker and filter paper several times with washing solution (3.9), dissolve the precipitate on the filter paper in the original beaker with 50mL hydrochloric acid (3.2), transfer the solution into a 100mL volumetric flask, dilute to the mark with water, and mix. 6.3.2 Place the combined solution (6.3, 1) in an electrolytic cell and introduce 3 ml of nitrogen (3.12). Measure the wave height at a potential of -0.46 V. 6.3.3 Subtract the wave height of the blank test performed with the sample and obtain the corresponding amount from the working curve. 6.4 Drawing of the working curve
Take 0, 2.50, 5.00, 10.00, 15.00, 20.00, 25.00 mL of the tin standard solution (3.12) and proceed as in 6.3.1 from the addition of 20 mL of nitric acid (3.1) to 6.3.2. Subtract the wave height of the reagent blank and draw the working curve with the amount as the horizontal axis and the wave height as the vertical axis. 7 Calculation of analysis results
Calculate the percentage of tweezers according to the following formula:
m1×100
Snt%) =
Where: m1—the amount found from the working curve, 8!The sample volume, start.
Note: The analysis results are expressed to the third decimal place. 8 Allowable difference
The difference in the analysis results between the experimental spaces should not be greater than the allowable difference listed in Table 2. Additional remarks:
0.005~-0.010
>0.010~0.020
>0.020-0.050
>0,050-0,100
This standard was drafted by Jilin Ferroalloy Factory, CB 5059.4
The level mark of this standard
GB 5059.4--88 I
Northern difference
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