This standard specifies the determination method of thallium content in pure lead. This standard is applicable to the determination of thallium in pure lead. Determination range: 0.00030% to 0.010%. GB/T 4103.12-2000 Chemical analysis method for lead and lead alloys Determination of thallium content GB/T4103.12-2000 Standard download decompression password: www.bzxz.net

GB/T4103.12—2000 Determination of Thallium by Crystal Violet Spectrophotometry. This standard is a reconfirmation of GB/T472.9-1984 Chemical Analysis Method for Lead Ingots. This standard is only an editorial revision. This standard complies with: Unit 1: Rules for drafting and expressing standards Part 1: GB/T 1.1-1993 Guidelines for standardization work Basic provisions GB/T1.4—1988 Guidelines for standardization work Provisions for the preparation of chemical analysis method standards GB/T1167-1978 General principles and general provisions for chemical analysis method standards for metallurgical products GB/T7729-1987 General principles for spectrophotometric methods for chemical analysis of metallurgical products GB/T17433-1998 Basic terms for chemical analysis of metallurgical products This standard replaces GB/T472.9-1984 from the date of its 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 Copper Processing Plant of Baiyin Nonferrous Metals Company. This standard was drafted by Shenyang Smelter.
The main drafters of this standard are Xu Minglan and Min Jianmei. 153
1 Scope
National Standard of the People's Republic of China
Chemical Analysis Methods of Lead and Lead Alloys
Determination of Thallium Content
Methods for chemical analysis of lead and lead allays-Determination of thallium content This standard specifies the determination method of thallium content in pure lead. This standard is applicable to the determination of thallium in pure lead. The determination range is 0.00030% to 0.010%. 2 Method Summary
GB/T 4103.12.-2000
Replaces GB/T172.91981
The sample is dissolved in nitric acid and hydrochloric acid to separate the lead as lead fluoride precipitate. Crystal violet reacts with (III) to form a colored complex, which is extracted with isoamyl acetate in a plate acid (c(HCl)=0.12mol/L) medium, and the absorbance of the organic phase is measured at a wavelength of 595nm on a spectrophotometer.
3 Reagents
3.1 Isoamyl acetate.
3.2 Hydrochloric acid (p1.19 g/mL).
3.3 Hydrogen peroxide (30%).
3.4 ​​Hydrochloric acid (0.12mol/L).
3.5 Nitric acid (1+2).
3.6 Saturated sodium chloride solution, high purity.
3.7 Potassium permanganate solution (10g/1.).
3.8 Crystal violet solution (0.5 zone/L).
3.9 Caesium standard stock solution: Weigh 0.1117g of chromium oxide standard reagent that has been pre-dried at 100-105C for 1h and cooled to room temperature in a desiccator, place it in a 200ml beaker, add 20mL of hydrochloric acid (1+1) to dissolve, transfer it to a 1000ml volumetric flask with hydrochloric acid (1+4) to dilute to the mark, and mix. This solution contains 100μg thallium in 1mL. 3.10 Caesium standard solution: Transfer 20.00mL of thallium standard stock solution (3.9) to a 1000ml volumetric flask, dilute to the mark with hydrochloric acid (2:100), and mix. This solution contains 2μg thallium in 1mL. 4 Apparatus
Spectrophotometer.
5 Analysis steps
5.1 Sample
Approved by the State Administration of Quality and Technical Supervision on 2000-08-28 154
Implemented on 2000-12-01
Weigh 1.0000g of sample.
Carry out 2 independent determinations and take the average. 5.2 Vacuum test
Carry out vacuum test with the sample.
5.3 Determination
GB/T 4103.12--2000
5.3.1 Place the sample (5.1) in a 50mL beaker, add 15mL nitric acid and 5 drops of hydrochloric acid (3.2), heat at low temperature to decompose, and evaporate for ten minutes in a boiling water bath.
5.3.2 Add 20ml hydrochloric acid (3.4) and heat at low temperature to dissolve the salts. Add 5ml saturated sodium chloride solution, wash the surface blood and the wall of the cup with a small amount of hydrochloric acid (3.1), and cool with running water. Filter with medium-speed quantitative filter paper, wash the beaker and precipitate with hydrochloric acid (3.4) 7 to 8 times. Transfer the filtrate into a 125ml separatory funnel; or transfer the filtrate into a 100mL volumetric flask, dilute to the scale with hydrochloric acid (3.4), and mix well. Take the test solution into a 125mL separatory funnel according to Table 1. Add hydrochloric acid (3.4) to make the volume of the solution in the separatory funnel 60ml. Table 1
Thallium content, %
0. 000 30~0.001 0
0. 001 0~-0. 002 0
≥0. 002 0~ 0. 005 0
>0. 005 0~0. 010
Take aliquots of test solution, ml
5.3.3 Add 4 drops of potassium permanganate solution and mix. Let stand for 2~3 minutes, add 2 drops of hydrogen peroxide, and after the color of potassium permanganate fades, add 10.00mL of acetyl acetate and 1mL of crystal violet solution, shake for 1 minute, let stand for stratification, and discard the aqueous phase. Centrifuge the organic phase for 1 minute or add 1g of anhydrous sodium sulfate to remove moisture.
5.3.4 Pipette part of the organic phase into 1cm absorption III, and measure its absorbance at a wavelength of 595nm on a spectrophotometer with the blank solution accompanying the sample as a reference. Obtain the corresponding amount of thallium from the curve drawn above. 5.4 Plotting the working curve
5.4.1 Pipette 0, 1.00, 2.00, 3.00, 4.00, and 5.00mL of thallium standard solution (3.10) into a component funnel respectively, and dilute to 60mL with hydrochloric acid (3.4). Proceed as in 5.3.3. 5.4.2 Pipette part of the solution (5.4.1) into 1cm absorption III, and measure its absorbance at a wavelength of 595nm on a spectrophotometer with the reagent blank as a reference. Plot the working curve with the concentration of thallium as the horizontal axis and the absorbance as the vertical axis. 6 Expression of analysis results
Calculate the thallium content according to formula (1):
Formula: m
Tl(%) m: V.× 10-bzxZ.net
The amount of thallium obtained from the working curve, ug; V.-——total volume of test solution, mL;
V. The volume of test solution taken, ml;
mThe mass of the sample·g.
The result is expressed to three decimal places. If the content is less than 0.010%, it is expressed to four decimal places; if it is less than 0.0010%, it is expressed to five decimal places.
7 Allowable difference
The difference in analysis results between laboratories shall not be greater than the allowable difference listed in Table 2. 155
Armor content
0. 000 30 ~0. 001 0
>0. 001 0~ 0. 002 0
>0. 002 0 ~ 0. 005 0
>0. 005 0~ 0. 010
GB/T 4103. 12--2000
Allowable difference
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