This standard specifies the determination method of selenium content in lead and lead alloys. This standard is applicable to the determination of selenium content in lead and lead alloys. Determination range: 0.0050% to 0.10%. GB/T 4103.7-2000 Chemical analysis method for lead and lead alloys Determination of selenium content GB/T4103.7-2000 Standard download decompression password: www.bzxz.net

GB/T4103.7—2000
This standard is a revision of the method part of "Determination of selenium content" in GB/T4103.10--1983 (Chemical analysis method of lead-based alloys-Determination of selenium and tellurium content by oscillographic polarography).
This standard complies with:
Unit 1: Rules for drafting and expressing standards Part 1: GB/T1.1--1993
Guidelines for standardization work
Basic provisions for standard writing
GB/T1.4--1988 Guidelines for standardization work
Provisions for the preparation of chemical analysis method standards
GB/T1467--1978 Standards for chemical analysis methods for metallurgical products General principles and general provisions of the standard GB/T17433-1998 Basic terminology for chemical analysis of metallurgical products This standard partially replaces GB/T4103.10-1983 from the date of entry into force. This standard is proposed by the State Bureau of Nonferrous Metals Industry. This standard is under the jurisdiction of the China Nonferrous Metals Industry Standard Metrology and Quality Research Institute. This standard was drafted by Shenyang Smelter and Northwest Processing Plant of Baiyin Nonferrous Metals Company. This standard was drafted by Shenyang Smelter.
The main drafters of this standard are Huang Xiumei and Zhang Quan. 129
1 Scope
National Standard of the People's Republic of China
Chemical analysis methods of lead and lead alloys
Determination of selenium content
Methods for chemical analysis of lead and lead alloys--Determination of selenium content This standard specifies the method for the determination of selenium content in lead and lead alloys, GB/T 4103.7: 200C
Partially replace B 1183
This standard is applicable to the determination of selenium content in lead and lead alloys. Determination range 0.0050% ~ 0.10% 2 Method Summary
In hydrochloric acid [c (HCI) = 6mol/L1 medium, arsenic is used as a carrier to co-precipitate selenium, separated from the lead matrix, and in sodium sulfite-potassium periodate-mixed bottom solution. Determine the first-order derivative catalytic wave of selenium. 3 Reagents
3.1 Absorbent cotton (medical).
3.2 Tartaric acid.
3.3 Sodium hypophosphite.
3.4 ​​Potassium periodate.
3.5 Formaldehyde.
3.6 Hydrochloric acid (pl., 19g/ml.).
3.7 Nitric acid (pl. 42 g/mL).
3.8 Peracid (pl.67g/mL)
3.9 Ammonia (00.90 g/mL).
3.10 Hydrochloric acid (7+1).
3.11 Nitric acid (1+1).
Silver nitrate solution (10g/1).
Sodium sulfite solution (200g/L).
Sodium hydroxide solution (100g/L).
Phenolic acid indicator (1g/1. ethanol solution). 3.16 Arsenic solution: Weigh 1.3000g of arsenic trioxide into a 100mL beaker, add 15ml of sodium hydroxide solution (3.14). Heat slightly to dissolve, transfer to a 500mL volumetric flask, dilute to 200mL with water, use phenolic acid (3.15) as an indicator, neutralize with hydrochloric acid (3.10) until the semi-red color fades, and dilute to scale with water. This solution contains 2mg arsenic in 1mL. 3.17 Mixed base solution.
3.17.1 Weigh 0.5g of animal glue into a 200mL beaker, add 50ml of boiling water, and heat to dissolve. 3.17.2 Weigh 50g of ammonium muride and 5g of disodium ethylenediaminetetraacetate in a 500ml volumetric flask, add 200ml of ammonia water and 15ml of solution (3.17.1), and dilute with water to 500ml. GB/T 4103.7--2000
3.18 Sodium hypophosphite-hydrochloric acid washing solution: Dissolve 1g sodium hypophosphite in 100mL hydrochloric acid (5+95) and mix. 3.19 Potassium periodate solution: Dissolve 1g potassium periodate in 90mL water. Add 1mL ammonia water (3.9) and dilute with water to 10:ml. 3.20 Selenium standard stock solution: Weigh 0.1(000g) high purity selenium in a 200mL beaker. Add 10ml nitric acid (3.11) and dissolve it in a boiling water bath. Transfer it to 1000ml with water. 3.21 Selenium standard solution: Pipette 10.00 mL of selenium standard stock solution (3.20) into a 1000 mL volumetric flask, dilute to the mark with water and mix. 1 mL of this solution contains 1 g of selenium.
4 Instruments
Dongbo polarograph,
5 Analysis steps
5.1 Test materials
Weigh the sample according to Table 1, accurate to 0.0001 g. Table 1
Wine content
0. 005 0~-0. 010Www.bzxZ.net
0.010~~0.030
0.030~0.060
0.060~0.10
Sample quantity·name
Carry out 2 measurements independently and take the average value. 5.2 Empty self-test
Carry out empty self-test with the sample.
5.3, Determine
Test solution volume.ml
Subtract volume, ml
5. 00--10.00
Measurement volume.ml
5.3.1 Place the sample (5.1) in a 200mL beaker, add 1g tartaric acid, 10mL water, 4ml nitric acid (3.7), cover with 1 meter, and heat until the sample is completely dissolved!
5.3.2 Remove the sample, add 50ml hydrochloric acid (3.6), heat slightly, remove the sample and place it until the solution turns reddish brown, add 1~2ml aldehyde each time, and stir the beaker while adding until the reddish brown disappears, then add 40mL 60~80C hot water, add 2.5mL arsenic solution, 4g sodium hypophosphite, and stir to dissolve. Place on a low-temperature electric heating plate Boil slightly for 10 minutes, then keep warm in a water bath at 80~~90℃ for 60~120 minutes. 5.3.3 Filter the warm solution with absorbent cotton (keep warm and filter if necessary), and transfer all the precipitates into the funnel. Wash the table and beaker 3 times with detergent, and the precipitate 5 times, and then wash the beaker, table and precipitate with water until the filtrate is checked with silver nitrate solution and no silver chloride precipitation is generated. Remove the filtrate and washing liquid, transfer the absorbent cotton into the original beaker, rinse the beaker with 10~15ml nitric acid (3.7) and 4ml perchloric acid, digest the absorbent cotton on a low-temperature electric heating plate, and dissolve arsenic and selenium, then remove, cool, and transfer to a volumetric flask. 5.3.4 Take a quantitative test solution in a 50ml beaker, add 1mL nitric acid (3.7) and 0.5mL perchloric acid, steam at low temperature until smoke appears, remove and cool, then rinse the table III and the wall of the cup with a small amount of water until white smoke appears. During the evaporation process, shake the beaker from time to time. It will take about 1 minute from the time white smoke appears.
5.3.5 Rinse the beaker III and the beaker wall with a little water, add 3.0mL sodium sulfite solution, let it stand for 15-20min, then add 3ml of iodic acid unloading solution and 5.0mL of mixed base solution, transfer to a 25mL volumetric flask and mix well. 5.3.6 Take part of the solution (5.3.5) and place it in the center of the electrolytic cell on an oscillographic polarograph: Measure the first-order derivative wave height of selenium (-0.6V is the starting potential), and remove the blank value accompanying the sample. 5.4 Standard reference solution used in direct comparison method: Select 3 portions of selenium standard solution equivalent to the selenium content of the test sample and place them in 3 50ml beakers4, add 1ml of sodium thiocyanate to each beaker. (3.7) Proceed as follows according to 5.3.4 to 5.3.6, take the average value and calculate the result by direct comparison method. 6 Expression of analytical results: Calculate the percentage content (%) of selenium according to (1): Se(%) = V. + H, X 10--
mo- H.
Wherein - concentration of selenium standard solution, ug/mL. Volume of selenium standard solution taken during determination, mL; H,--wave height of test solution, mm;
Hwave height of standard solution. mm;
+++...+( )
m.-mass of test material.
The result is expressed to two decimal places. If the selenium content is less than 0.10%, it is expressed to three decimal places; if it is less than 0.010%, it is expressed to four decimal places.
Allowable difference
The difference between the analysis results of laboratories should not be greater than the allowable difference listed in Table 2 Table 2
Selenium content
0. 005 0～ 0. 010
>0. 010~0,030
>0. 030~0, 070
70. 070~0. 10
allowable difference
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