This standard specifies the determination method of chlorine content in bismuth. This standard is applicable to the determination of chlorine content in bismuth. Determination range: 0.001%~0.006%. GB/T 8220.8-1998 Chemical analysis method for bismuth - Determination of chlorine content by distillation-mercuric thiocyanate spectrophotometry GB/T8220.8-1998 Standard download decompression password: www.bzxz.net

GB/T8220.8-1998
This standard is a revision of GB8220.8-87 "Chemical analysis method for bismuth: distillation-thiocyanate multiplication spectrophotometric method for determination of chlorine content". This standard complies with:
GB/T1.4-1988 Guidelines for standardization work: Provisions for the preparation of chemical analysis method standards GB/T1467--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 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: Unit 1: Rules for drafting and expressing standards: Part 1: Basic provisions for the preparation of standards". From the date of implementation, this standard will also replace GB8220.8-87. 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. This standard was drafted by Zhuzhou Smelter. Drafting units of this standard: Zhuzhou Smelter, Shanghai Smelter. Main drafters of this standard: Yan Jiliang, Yu Zhenxiang, Liu Yuhua. This standard was first issued in 1966, revised for the first time in October 1976, and revised for the second time in September 1987. 343
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of bismuth
Cloud distillation
Determination of chlorine content by mercuric thiocyanate spectrophotometric method
Methods for chemical analysis of bismuth--Determination of chlorine content-Distillation-mercuric thiocyanate photometric method This standard specifies the determination method of chlorine content in bismuth. This standard is applicable to the determination of chlorine content in bismuth. Determination range: 0.001% to 0.006%. 2 Method Summary
GB/T 8220. 8 -- 1998
Replaces GB 8220.887
The sample is dissolved in nitric acid and distilled in a nitric acid medium at a temperature of 250℃±20℃. The effluent is absorbed in a sodium hydroxide solution. Mercuric thiocyanate and ferric perchlorate are added. The chloride formed reacts with mercuric thiocyanate to release thiocyanate and react with iron (sub) to develop color. The absorbance is measured at a wavelength of 460nm on a spectrophotometer. 3 Reagents
The reagent preparation and determination process are all made with double distilled water added with a small amount of sodium hydroxide. 3.1 Reduced iron powder.
3.2 Sodium hydroxide, high purity.
3.3 Nitric acid (pl.42g/ml.), ultrapure. 3.4 Perchloric acid (ol.67g/mL).
3.5 Nitrogen, high purity.
3.6 Mercuric thiocyanate-methanol solution (5g/L): Weigh 0.5g mercuric thiocyanate into a 250mL beaker, add 100ml methanol, and transfer to a brown bottle for storage after complete dissolution.
3.7 Ferric perchlorate solution: Weigh 7g reduced iron powder into a 400mL beaker, add 200mL nitric acid (2+1, ultrapure). Heat to dissolve. Add 60mL perchloric acid (3.4), heat until perchloric acid smokes and continue heating until the solution is reddish brown, cool. Dilute to 500mL with water and mix well.
3.8 Sodium hydroxide solution (0.2mol/L), high purity. 3.9 Chlorine standard stock solution: Weigh 0.2102g potassium chloride (superior grade) that has been burned at 500℃ for 30min and cooled to room temperature in a desiccator, place in a 250ml beaker, dissolve in appropriate amount of water, transfer to a 1000ml volumetric flask, dilute to scale with water, and mix. This solution contains 0.1 mg chlorine per ml.
3.10 Chlorine standard solution: Transfer 50.00mL chlorine standard stock solution (3.9) to a 500ml volumetric flask, dilute to scale with water, and mix. This solution contains 10μg fluorine per ml.
Approved by the State Administration of Quality and Technical Supervision on August 19, 1998 344
Implementation on March 1, 1999
4 Instruments and devices
4.1 Spectrophotometer.
4.2 Distiller (see Figure 1).
GB/T8220.8-1998
Unit: mm
Cooling water
1 Distiller (50ml.916mm standard inverted ground flat bottom distillation bottle); 2-$16mm standard inverted ground mouth; 3 Nitrogen inlet pipe (Φ=6mml); 4 Condenser; 5 Conduit (gg3mm); 6 Absorption tube ($16mm scale test tube); 7 Temperature-controlled electric furnace Figure 1 Chlorine distillation device
4.3 Temperature-controlled electric furnace.
5 Analysis steps
5.1 Test material
Weigh the sample according to Table 1.
0. 001--0. 003
>0.003~0. 006bZxz.net
5.2 Empty self-test
Carry out an empty test with the test material.
5.3 Determination
GB/T 8220. 8—1998
5.3.1 Connect a 15mL absorption tube containing 8mL of sodium hydroxide solution (3.8) to the guide tube of the distillation apparatus, introduce nitrogen at a rate of 3 to 5 bubbles per second, and turn on the cooling water. 5.3.2 Place the sample (5.1) in a dry distillation flask, add 25mL of nitric acid (3.3), and then place the distillation flask on the distillation apparatus and place it on a temperature-controlled electric furnace.
5.3.3 Turn on the power supply, control the furnace temperature at 250℃±20℃, and distill for 1h. Turn off the power supply and remove the absorption tube. 5.3.4 Add 1.5mL of perchloric acid (3.4) to the absorption tube, mix well, cool to room temperature, add 1.0mL of mercuric thiocyanate-methanol solution (3.6), and mix. Add 3.0 ml of ferric perchlorate solution (3.7), dilute to the mark with water, and mix. Let stand for 20 minutes. 5.3.5 Transfer part of the solution (5.3.4) to a 3 cm absorbent tube, and measure its absorbance at a wavelength of 460 nm using the blank sample accompanying the sample as a reference. Find the corresponding amount of chlorine from the working curve. 5.4 Drawing of the working curve
5.4.1 Transfer 0, 0.50, 1.00, 1.50, 2.00, 2.50 and 3.00 ml of the chlorine standard solution (3.10) to a 15 ml colorimetric tube, and dilute to 8 ml with water. Proceed as in 5.3.4. 5.4.2: Transfer part of the solution (5.4.1) to a 3 cm absorbent tube III, and measure its absorbance at a wavelength of 460 nm using the reagent blank as a reference. Draw the working curve with the amount of chlorine as the horizontal axis and the absorbance as the vertical axis. 6 Calculation and expression of analysis results
Calculate the percentage of chlorine according to the following formula:
Wherein: mj-
Cl(%) = m_ × 10-6
-The amount of chlorine found on the working curve, g; mo is the mass of the sample, g.
The analysis result should retain 2 significant figures.
7 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. Table 2
0. 001 0~0. 003 0
>0. 003 0~0. 006 0
Allowable difference
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