GB/T 8220.9-1998 Chemical analysis method for bismuth - Arsenic coprecipitation-oscillographic polarographic method for determination of tellurium content
Some standard content:
GB/T 8220. 9 -1998
This standard is a revision of GB8220.9--87 "Bismuth Chemical Analysis Method Oscillopolarographic Determination of Quantity". During the revision, the original organic extraction separation was changed to coprecipitation separation, and the original polarographic determination method was retained unchanged. This standard complies with:
GB/T1.4-1988 Standardization Work Guidelines
Provisions for the Preparation of Chemical Analysis Methods Standards
GB/T1467-1978 General Principles and General Provisions for Chemical Analysis Methods of Metallurgical Products GB/T7729-1987 General Principles for Spectrophotometric Methods for Chemical Analysis of Metallurgical Products This standard is a supporting standard for GB/T915-1995 "Bismuth". The preparation method of this standard complies with the provisions of GB/T1.1--1993 "Standardization Work Guidelines Part 1: Basic Provisions for Standard Preparation". From the date of implementation, this standard will also replace GB8220.9--87. This standard was proposed by China National Nonferrous Metals Industry Corporation. This standard is under the jurisdiction of the Standardization and Metrology Research Institute of China National Nonferrous Metals Industry Corporation. This standard was drafted by Zhuzhou Refinery.
The main drafters of this standard are Zhong Ming and Xiang Delei. Unit 1: Rules for drafting and expressing standards This standard was first issued in 1966, revised for the first time in October 1976, and revised for the second time in September 1987. 347
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of bismuth-Determination of tellurium content--Coprecipitation with arsenic-oscillopolarographic method
Methods for chemical analysis of bismuth-Determination of tellurium content--Coprecipitation with arsenic-oscillopolarographic method This standard specifies the determination method of tellurium content in bismuth. This standard is applicable to the determination of the exact content in bismuth. Determination range: 0.0002% to 0.0015%. 2 Method Summary
GB/T 8220. 9- 1998
Replaces GI38220.9: 87
The sample is decomposed with nitric acid. In a 6 mol/L hydrochloric acid medium, copper sulfate is used as a catalyst, and arsenic is used to coprecipitate tellurium to separate it from the main bismuth. In a sulfuric acid-sodium chloride bottom solution, the peak current is measured at the peak potential of the oscillographic polarograph at -0.85V, and the tellurium content is calculated by the standard curve method. 3 Reagents
3.1 Sodium phosphate.
3.2 Hydrochloric acid (pl.19 g/mL), high-grade purity. 3.3 Nitric acid (al.42 g/ml.), high-grade purity. 3.4 Perchloric acid (pl.67 g/mL).
3.5 Hydrochloric acid (1+1), high-grade purity.
3.6 Nitric acid (2+1), high-grade purity.
Sulfuric acid (1+1), high-grade pure.
3.8Sodium hydroxide solution (200g/1.). 3.9Sodium chloride solution (300g/L), high-grade pure. 3.10Copper sulfate solution (CuS0),·5H,O100 g/L). 3.11Hydroxylamine hydrochloride solution (200g/L), prepare it when needed. 3.12Hydrochloric acid washing solution: add 1g sodium hypophosphite to 500mL hydrochloric acid (1mol/L). 3.13Bromolybdenum saturated nitric acid: add an appropriate amount of bromine to nitric acid to make it saturated. 3.14Methyl red ethanol solution (0.5g/L). 3.15Arsenic solution: weigh 0.66g arsenic trioxide into a 100ml beaker, add 20ml sodium hydroxide solution (3.8), heat to dissolve. Cool, transfer to a 500mL volumetric flask, dilute to the mark with water, and mix. This solution contains 1mg arsenic per ml. 3.16 Bismuth solution: Weigh 0.5g of metallic bismuth (≥99.99%) and place it in a 150ml beaker, add 5ml of nitric acid (3.6), heat to dissolve, remove, add 3ml of perchloric acid (3.4), steam until gastric smoke, remove, and cool. Wash the surface blood and the wall of the cup with water and steam until gastric smoke, remove. Cool, add 10ml of perchloric acid (3.4), transfer to a 250ml volumetric flask, dilute to scale with water, and mix well. This solution contains 2mg of bismuth in 1ml. 3.17 Tellurium standard storage solution: Weigh 0.1000g tellurium (≥99.99%) and place it in a 200ml beaker. 1. Add 10ml nitric acid (3.6) Approved by the State Administration of Quality and Technical Supervision on August 19, 1998 348
Implemented on March 1, 1999 GB/T8220.9--1998
Heat to dissolve, remove, and cool. Add 3ml perchloric acid (3.4), steam until smoke appears, remove, cool, blow water to clean Table III and the wall of the cup, steam until smoke appears, remove, and cool. Add 10mL perchloric acid (3.4) and transfer to a 1000mL volumetric flask. Dilute to the mark with water and mix. This solution contains 0.1mg in 1mL.
3.18 Tellurium standard solution: Transfer 10.00mL tellurium standard storage solution (3.17) to a 500mL volumetric flask, dilute to the mark with water and mix. This solution contains 2ug tellurium in 1mL.
4 Instruments
Oscillographic polarograph.
5 Analysis steps
5.1 Test materialsbZxz.net
Weigh the samples according to Table 1.
0. 000 2 ~ 0. 000 7
>0. 000 7~ 0. 001 5
5.2 Blank test
Carry out a blank test together with the test materials.
5.3 Determination
5.3.1 Place the sample (5.1) in a 100ml beaker, add 10ml nitric acid (3.6), heat to dissolve, and evaporate at low temperature until nearly dry. Add 4ml hydrochloric acid (3.2), evaporate again until nearly dry and repeat the operation once. Remove and cool. 5.3.2 Add 50ml hydrochloric acid (3.5), 3ml solution (3.15), 1ml copper sulfate solution (3.10), heat on a hot plate to dissolve the salts, add 1g sodium hypophosphite (3.1), stir, boil for 5min, keep warm for 30min, filter with 0.5g absorbent cotton, wash the absorbent cotton twice with hydrochloric acid solution (3.12), wash the beaker 3 times with hot hydrochloric acid solution (3.12) after filtering, wash the precipitate 6 times, then wash the beaker 3 times with hot water, and wash the precipitate 5 times. Dissolve the precipitate in the source beaker with 6ml bromine saturated nitric acid (3.13) in batches, and wash the cotton wool with hot water for 3 times. Rinse the beaker wall with 2ml bromine saturated nitric acid (3.13), add 2ml perchloric acid (3.4), cover with a watch glass, steam at low temperature until smoking, remove, and cool. Blow water to wash the blood and the beaker wall and steam again until smoking, remove, and cool. 5.3.3 Blow in a small amount of water, add 0.5ml bismuth solution (3.16), 1 drop of methyl red ethanol solution (3.14), adjust with sodium hydroxide solution (3.8) until the solution just turns yellow, transfer to a 25ml volumetric flask, wash the beaker with 0.2ml sulfuric acid (3.7) and 10.0ml sodium chloride solution (3.9), and then wash with water twice, combine the washing liquid in the volumetric flask, add 2.5ml hydroxylamine hydrochloride solution (3.11), dilute to the scale with water, mix well, and let stand for 15 minutes.
5.3.4 Pour a small amount of solution into the electrolysis cup and measure its peak current at the peak potential of the oscilloscope polarograph at -0.85V. Subtract the peak current of the empty sample solution and find the corresponding tellurium content on the working curve. 5.4 Drawing of working curve
5.4.7 Take 0, 1.50, 3.00, 4.50, 6.00, 7.50mL of tellurium standard solution (3.18) and place them in a series of 25mL containers respectively. Proceed as in 5.3.3.
5.4.2 Pour a small amount of solution into the electrolysis cup and measure its peak current at the peak potential of the oscilloscope polarograph at -0.85V. Subtract the peak current of the empty reagent solution and draw the working curve with the tellurium content as the abscissa and the peak current as the ordinate. 6 Calculation and expression of analysis results
Calculate the percentage of the sieve according to the following formula:
GB/T8220.9—1998
Te(%) = m × 10-6
-The amount of tellurium found from the working curve, ug; mi-
m\-The mass of the sample, g.
The analysis results should retain two significant figures.
Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0. 000 2~ 0. 000 7
0.0007~0.0015
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