This standard specifies the determination method of cadmium oxide content in direct zinc oxide. This standard is applicable to the determination of cadmium oxide content in direct zinc oxide. Determination range: 0.0020～0.30%. GB/T 4372.4-2001 Chemical analysis method of direct zinc oxide Determination of cadmium oxide content by atomic absorption spectrometry GB/T4372.4-2001 Standard download decompression password: www.bzxz.net

GB/T 4372.4--2001
This standard is a revision of GB/T4372.2--1984 "Zinc Oxide (Direct Method) Chemical Analysis Method Phosphoric Acid Solution Polarographic Determination of Lead Oxide and Cadmium Oxide". The main content of the revision is the determination of cadmium oxide by atomic absorption spectrometry. The preparation of this standard follows:
GB/T1467-1978
General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products GB/T 7728--1987
General Principles for Chemical Analysis of Metallurgical Products Flame Atomic Absorption Spectrometry GB/T17433-1998 Basic Terminology for Chemical Analysis of Metallurgical Products This standard will replace GB/T4372.2-1984 from the date of implementation. Appendix A of this standard is a reminder appendix.
This standard is proposed by China Nonferrous Metals Industry Association. This standard is under the jurisdiction of China Nonferrous Metals Industry Standard Metrology Quality Research Institute. This standard was drafted by Shuikoushan Mining Bureau. The main drafters of this standard are Kuang Haiyan, Yao Xiaohong, Mao Yanling and Tan Pingsheng. The National Technical Committee for Standardization of Nonferrous Metals is entrusted with the interpretation of this standard. 123
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of zinc oxide produced by direct process
Determination of cadmium oxide content by atomic absorption spectrometry
Methods for chemical analysis of zincoxide produced by direct process--- Determination of cadmium oxide content--Atomic absorption spectrometry method This standard specifies the method for determining the cadmium oxide content in zinc oxide produced by direct process. GB/T 4372.4--2001
Replaces GB/T4372.2-—1984
This standard is applicable to the determination of the oxide content in zinc oxide produced by direct process. Determination range: 0.0020%～0.30%. 2 Method Summary
The sample is dissolved in nitric acid. In a dilute nitric acid (5+95) medium, an air-acetylene flame is used to measure the absorbance of cadmium at a wavelength of 228.8nm on an atomic absorption spectrometer. The content of cadmium oxide is calculated using the standard curve method. 3 Reagents
3.1 Nitric acid (1+1).
3.2 Cadmium standard stock solution: Weigh 0.1000g of pure cadmium (99.99%) and place it in a 250mL beaker, add 10mL of nitric acid (3.1), dissolve it with slight heat, remove it and cool it, transfer it to a 1000mL volumetric flask, dilute it to the mark with water, mix it well, and 1mL of this solution contains 0.10mg. 3.3 Cadmium standard solution: Weigh 10.00mL of cadmium standard stock solution (3.2) in a 100mL volumetric flask, add 5mL of nitric acid (3.1), dilute it to the mark with water, mix it well, and 1mL of this solution contains 10μg of cadmium. 4 Instruments
Atomic absorption spectrometer with hollow cathode lamp. Under the best working conditions of the instrument, any instrument that can meet the following indicators can be used. Sensitivity: In a solution consistent with the matrix of the sample solution to be measured, the characteristic concentration of cadmium should not be greater than 0.03μg/mL. Precision: When the absorbance is measured 10 times with the highest concentration standard solution, its standard deviation should not exceed 1.0% of the average absorbance; when the absorbance is measured 10 times with the lowest concentration standard solution (not the zero standard solution), its standard deviation should not exceed 0.5% of the average absorbance of the highest concentration standard solution.
Linearity of working curve: Divide the working curve into five sections according to concentration. The ratio of the absorbance difference of the highest section to the absorbance difference of the lowest section should not be less than 0.7. wwW.bzxz.Net
See Appendix A (Suggested Appendix) for instrument working conditions. 5 Analysis steps
5.1 Test material
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on July 2001~124
Implemented on December 1, 2001
Weigh the sample according to Table 1, accurate to 0.0001g. Mass fraction of cadmium oxide, %
0.002 0~0.010
>0.010～0.025
>0.025～0.100
>0.100～0.300
5.2 Blank test
Carry out a blank test along with the test material.
5.3 Determination
GB/T 4372.4--2001
Test material quantity,
Test solution volume, ml
5.3.1 Place the test material (5.1) in a 150mL beaker, add 5mL nitric acid (3.1) and cover with blood, place on a hot plate and heat slightly to dissolve, after complete dissolution, remove and cool, blow water on the table and the wall of the cup, transfer to a 50mL volumetric flask, dilute with water to the scale, and mix. 5.3.2 Transfer the test solution according to Table 1 to a 50mL volumetric flask, add 5mL nitric acid (3.1), dilute with water to the scale, and mix. 5.3.3 Use air-acetylene flame at the wavelength of 228.8nm of the atomic absorption spectrometer, adjust to zero with water, and measure the absorbance of the test solution. Subtract the absorbance of the blank test solution from the measured absorbance, and find the corresponding cadmium concentration from the working curve. 5.4 Drawing of working curve
5.4.1 Take 0, 2.00, 4.00, 6.00, 8.00, 10.00mL of standard solution (3.3) and place them in a set of 100mL volumetric flasks respectively, add 10mL of nitric acid (3.1), dilute to the mark with water and mix well. 5.4.2 Under the same conditions as the test sample solution, measure the absorbance of the series of standard solutions. Draw the working curve with the concentration as the abscissa and the absorbance (minus the absorbance of the zero concentration solution) as the ordinate. 6 Expression of analysis results
Calculate the mass fraction of cadmium oxide according to formula (1): w(cao) - :V Vx 1*×1.142 3 × 100m.V.
Where: w(CdO)-
Mass fraction of cadmium oxide, %;
c-Cadmium concentration obtained from the working curve, μg/mL; V. ——Total volume of test solution, mL; Vi-Volume of test solution taken out, mL,
V.——Volume of test solution after dilution, mL; m
1. 142 3---
7Permissible difference
-Mass of test sample, g;
-Coefficient of cadmium converted to oxidation.
The difference in analysis results between laboratories should not be greater than the permissible difference listed in Table 2. Table 2
Mass fraction of cadmium oxide
0. 002 0 ~ 0. 008 0
>0. 008 0 ~ 0. 025
>0. 025~0.060
>0. 060~0. 100
>0. 100~～0. 300
Allowance
GB/T4372.4-2001
Appendix A
(Suggestive Appendix)
Instrument Working Conditions
The reference working conditions of GGX-5 atomic absorption spectrometer are shown in Table A1: Table A1
Wavelength, nm
Lamp current, mA
Monochromator current, nm
Air flow, L/min
Acetylene flow, L/min
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