This standard specifies the determination method of antimony content in bismuth. This standard is applicable to the determination of antimony content in bismuth. Determination range: 0.0002%~0.0025%. GB/T 8220.3-1998 Chemical analysis method for bismuth Malachite green spectrophotometric method for determination of antimony content GB/T8220.3-1998 Standard download decompression password: www.bzxz.net

GB/T8220.3--1998
This standard is a revision of GB8220.3--87 "Chemical analysis method for bismuth - determination of antimony content by malachite green spectrophotometry". In order to meet the requirements of GB/T915-1995 "Bismuth", the lower limit of determination was extended from 0.0003% to 0.0002% during the revision. This standard complies with:
GB/T1.4-1988 Standardization Guidelines Rules for the Preparation of Chemical Analysis Methods GB/T1467-1978 General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products GB/T7729-1987 General Rules 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 "Guidelines for Standardization Work Section 1: Rules for the Drafting and Expression of Standards Part 1: Basic Provisions for the Preparation of Standards". From the date of implementation, this standard will replace GB8220.3-87. This standard was proposed by China Nonferrous Metals Industry Corporation. This standard is under the jurisdiction of the Standardization and Metrology Research Institute of China Nonferrous Metals Industry Corporation. The drafting units of this standard are Zhuzhou Smelter and Shanghai Smelter. The main drafters of this standard are Wang Xiren and Cao Qianqian. This standard was first issued in 1966, revised for the first time in October 1976, and revised for the second time in September 1987. 319
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of bismuth
Melachite green spectrophotometric method
Methods for chemical analysis of bismuth-- Determination of antimony content --Melachite green photometric method This standard specifies the method for the determination of antimony content in bismuth. This standard is applicable to the determination of antimony content in bismuth. Determination range: 0.0002%～0.0025%. 2 Summary of method
GB/T 8220. 3 --- 1998
Replaces GB8220.3---87
The sample is dissolved in nitric acid. In the hydrochloric acid medium, the complex anion of pentavalent antimony [SbCl. }- forms a poorly soluble compound with malachite green, which is extracted with toluene and its absorbance is measured at a wavelength of 640nm by a spectrophotometer. 3 Reagents
3.1 Toluene.
3.2 Nitric acid (pl.42 g/mL).
3. 3 Sulfuric acid (pl.84 g/mL).
3.4 ​​Hydrochloric acid (2+1).
3.5 Stannous chloride solution (100g/L): Weigh 10g of stannous chloride (SnClz·2H20) in a 250mL beaker, add 50ml of hydrochloric acid (3.4), stir to dissolve, and dilute to 100mL with hydrochloric acid (3.4), mix well. 3.6 Sodium nitrite solution (100g/L).
3.7 Saturated urea solution.
3.8 Malachite green solution (2g/L).
3.9 Antimony standard stock solution: Weigh 0.1000g of metallic antimony (=99.9%) into a 250mL beaker, add 20ml of sulfuric acid (3.3) and heat to dissolve, remove and cool. Add 5mL of hydrochloric acid (3.4) to dissolve the salts with slight heat, cool to room temperature, transfer hydrochloric acid (3.4) into a 1000mL volumetric flask and dilute to scale, mix well. This solution contains 0.1mg antimony per mL. 3.10 Antimony standard solution: Transfer 10.00mL of standard stock solution (3.9) into a 500mL volumetric flask, dilute to scale with hydrochloric acid (3.4), mix well. This solution contains 2μg antimony per mL. 4 Instruments
Spectrophotometer. www.bzxz.net
5 Analysis steps
5.1 Test material
Approved by the State Administration of Quality and Technical Supervision on August 19, 1998, 320
Implemented on March 1, 1999
Weigh the sample according to Table 1.
Antimony content, %
0. 000 2-~0. 000 4
20. 000 4-~0. 001 5
0. 001 5~~0. 002 5
5.2 Blank test
Carry out a blank test together with the test material.
5.3 Determination
GB/T 8220. 3- 1998
Test material + &
Absorption thickness. cm
5.3.1 Place the test material (5.1) in a 100mL beaker, add 5mL nitric acid (3.2), heat slightly to dissolve the test material and evaporate to about 0.5ml, remove, add 2ml sulfuric acid (3.3), shake continuously until a colored precipitate is precipitated, evaporate at low temperature until sulfur trioxide smoke is emitted, and then at high temperature until white smoke is emitted. Remove and cool. Add 5ml hydrochloric acid (3.4), heat slightly to dissolve the salts. 5.3.2 Transfer the test solution into a 125ml separatory funnel, wash the beaker twice with 5ml hydrochloric acid (3.4), and combine them in the separatory funnel. 5.3.3 Add 1ml stannous chloride solution (3.5) into the separatory funnel and mix. Let stand for 2min, add 2ml sodium nitrite solution (3.6), mix well, and let stand for 5min. Add 4ml urea saturated solution (3.7), shake the separatory funnel until a large amount of gas escapes. Add 20.0ml benzene (3.1) and 40ml water, immediately add 1mL malachite green solution (3.8), shake vigorously for 1min, let stand for 5min. Discard the aqueous phase, transfer the organic phase into a dry 25ml colorimetric tube, add 2 drops of anhydrous ethanol, and mix. 5.3.4 Transfer part of the organic phase into the absorption III shown in Table 1, and use the blank accompanying the sample as a reference to measure its absorbance at a wavelength of 640nm on a spectrophotometer.
5.4 Drawing of working curve
5.4.1 Working curve of Sb≤0.0004%
5.4.1.1 Transfer 0.0.50.1.00.1.50, 2.00, and 2.50ml of antimony standard solution (3.10) and place them in the lower 125ml separating funnel respectively. Dilute to 10mL with hydrochloric acid (3.4), and proceed as in 5.3.3. 5.4.1.2 Transfer part of the organic phase into a 2cm absorption dish, and use the reagent blank as a reference to measure its absorbance at a wavelength of 640nm on a spectrophotometer. Use the amount of antimony as the horizontal axis and the absorbance as the vertical axis to draw a working curve. 5.4.2 Working curve for Sb>0.0004%
5.4.2.1 Take 0, 1.00, 2.00, 4.00, 6.00, 8.00 mL of antimony standard solution (3.10) and place them in 125 mL of liquid separation liquid from Group F, dilute to 10 mL with hydrochloric acid (3.4), and proceed as in 5.3.3. 5.4.2.2 Transfer part of the organic phase to a 1 cm absorption dish and use the reagent blank as a reference. Measure its absorbance at a wavelength of 640 nm on a spectrophotometer, and plot the working curve with antimony as the horizontal axis and absorbance as the vertical axis. 6 Calculation and expression of analysis results
Calculate the percentage of antimony by the following formula:
Sb(%) =㎡× 10-
Wu Zhong: m,-.-The amount found on the self-made curve, ugmi-—The mass of the sample, g.
The analysis result shall be retained to 2 significant figures.
7 Allowable difference
The difference between the analysis results of the experimental space shall not be greater than the allowable difference listed in Table 2. 321
0. 000 2~~ 0. 000 4
>0. 000 4 ~ 0. 000 8
>0. 000 8 ~0. 001 5
0. 001 5~ 0. 002 3
8220.3-1998
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