This standard specifies the method for determining the copper content in bismuth. This standard is applicable to the determination of copper content in bismuth. Determination range: 0.0002%~0.004%. GB/T 8220.1-1998 Chemical analysis method for bis(acetaldehyde)-oxalyldihydrazone spectrophotometric method for determination of copper content GB/T8220.1-1998 Standard download decompression password: www.bzxz.net

GB/T8220.1—1998
This standard is a revision of GB8220.1-87 "Bismuth chemical analysis method - determination of copper content by diacetaldehyde oxalyl diamine spectrophotometry". In order to meet the requirements of GB/T915--1995 "Bismuth", the lower limit of determination of the method was extended from 0.0004% to 0.0002% during the revision. This standard complies with the following standards:
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 "Guidelines for Standardization Work Unit 1: Rules for Drafting and Presentation of Standards Part 1: Basic Provisions for the Preparation of Standards". From the date of implementation, this standard will replace GB8220.1-87 and Appendix A of GB/T915-1995 "Bismuth". This standard was proposed by China Nonferrous Metals Industry Corporation. This standard is under the jurisdiction of the Standards and Metrology Institute of China Nonferrous Metals Industry Corporation. This standard was drafted by Zhuzhou Smelter. The main drafters of this standard are Xiao Yongqiu and Yin Xingren. This standard was first issued in 1966, revised for the first time in October 1976, and revised for the second time in September 1987. 311
1 Scope
National Standard of the People's Republic of China
Chemical analysis methods for bismuth
Bis-acetaldehyde-oxalydihydrazone photometric methodMethods for chemical analysis of hismuth-Determination of copper content-.Bis-acetaldehyde-oxalydihydrazone photometric methodThis standard specifies the method for determination of copper content in bismuth. This standard is applicable to the determination of copper content in bismuth. Determination range: 0.0002%～0.004%. 2 Summary of the method
GB/T8220.1-1998
Replaces GB8220.187
The sample is decomposed by nitric acid. In an ammonia medium with a pH of 8 to 10, ammonium citrate is used to mask the main bismuth, and diacetaldehyde oxalyl (generated by the reaction of dicyclohexanone oxalyl and acetaldehyde) forms a stable purple-red complex with copper, and its absorbance is measured at a wavelength of 540 nm on a spectrophotometer.
3 Reagents
3.1 Ammonia water (p0.90 g/mL).
3.2 Acetaldehyde solution (40%).
3.3 Nitric acid (1+1).
3.4 ​​Ammonium citrate solution (300 g/L).
3.5 Dicyclohexanone oxalyl (BCO) solution (2 g/L): Weigh 1.0 g of BCO and place it in a 500 mL beaker, add 100 ml of anhydrous ethanol and 200 ml of hot water (50 to 60°C), and stir to dissolve (if there are undissolved particles, dissolve them with slight heat). Transfer to a 500mL volumetric flask. Dilute to the mark with water and mix.
3.6 Buffer solution (pH 9.2): Weigh 54g ammonium chloride and dissolve in water, add 63ml ammonia water (3.1), dilute to 1000ml with water and mix.
3.7 Neutral red ethanol solution (0.2g/L). 3.8 Copper standard stock solution: Weigh 1.000g metallic copper (3 99.95%), place in a 200mL beaker, add 20ml nitric acid (3.3), heat to dissolve, drive off nitrogen oxides, remove, and cool. Transfer to a 1000mL volumetric flask, add 10mL nitric acid (3.3), dilute to the mark with water and mix. This solution contains 1mg copper in 1mL. 3.9 Copper standard solution: Transfer 5.00mL copper standard stock solution (3.8), place in a 1000mL volumetric flask, dilute to the mark with water and mix. 1 mL of this solution contains 5 μg of copper.
3.10 Copper standard solution: Pipette 20.00 mL of copper standard solution (3.9) into a 100 mL volumetric flask, dilute to scale with water, and mix. 1 mL of this solution contains 1 μg of copper
Approved by the State Administration of Quality and Technical Supervision on August 19, 1998 312
Implemented from March 1, 1999
4 Instruments
Spectrophotometer.
5 Analysis steps
5.1 Test materials
Weigh the test samples according to Table 1.
0. 000 2--0. 000 5
>0. 000 5~0. 001 5
= 0. 001 5~0. 001 0
5.2 Blank test
Carry out a blank test together with the sample.
5.3 Determination
GB/T 8220. 1-
Sample g
Absorption III thickness, cm
5.3.1 Place the sample (5.1) in a 200mL beaker, add 8mL nitric acid (3.3), heat to dissolve and evaporate to 3~5mi, remove and cool. wwW.bzxz.Net
5.3.2 Add 10ml of ammonium citrate solution (3.4) and 1 drop of neutral red ethanol solution (3.7), neutralize with ammonia water (3.1) until the solution changes from red to yellow and 5 drops are in excess, transfer the solution to a 50ml volumetric flask, and dilute with water to about 30ml. 5.3.3 Add 5ml of buffer solution (3.6), 1.0ml of acetaldehyde solution (3.2), and 7.5ml of BCO solution (3.5), and mix each time you add a reagent. Dilute with water to the mark and mix. Color at 20~40℃ and leave for 1h. 5.3.4 Transfer part of the solution to the absorption IIIl shown in Table 1, use the blank accompanying the sample as a reference, measure the absorbance at a wavelength of 540nm with the F spectrophotometer, and find the corresponding copper amount from the working curve. 5.4 Drawing of working curve
5.4.1 Working curve of Cu≤0.0005%
5.4.1.1 Take 0, 1.00, 2.00, 3.00, 4.00, 5.00 ml of copper standard solution (3.10) and place them in a group of 50 ml bottles respectively. Proceed as in 5.3.2 to 5.3.3.
5.4.1.2 Transfer part of the solution into a 5 cm absorption dish, use the reagent blank as reference, measure its absorbance at a wavelength of 540 nm on a spectrophotometer, and draw a working curve with the copper content as the horizontal axis and the absorbance as the vertical axis. 5.4.2 Working curve for Cu>0.0005%
5.4.2.1 Take 0, 1.00, 2:00, 3.00, 4.00, 5.00mL of copper standard solution (3.9) and put them into a group of 50mL volumetric flasks respectively. The following is carried out according to 5.3.2 to 5.3.3.
5.4.2.2 Transfer part of the solution into a 3cm absorption tube, use the reagent space as a reference, measure its absorbance at a wavelength of 540nm on the spectrophotometer, and draw a working curve with the copper content as the horizontal axis and the absorbance as the vertical axis. 6 Calculation and expression of analysis results
Calculate the percentage of copper according to the following formula:
Where m.-the copper content found on the white working curve, ug, is the mass of the sample, g.
The analysis result should retain two significant figures. m, X 10
× 100
Allowable difference
GB/T8220.1—1998
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 5
0.0005~0.0015
>0.00150.0025
0.0025~0.0040
Allowable difference
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