This standard specifies the determination method of manganese oxide content in direct zinc oxide. This standard is applicable to the determination of manganese oxide content in direct zinc oxide. Determination range: 0.00005～0.0010%. GB/T 4372.5-2001 Chemical analysis method of direct zinc oxide - Determination of manganese content by atomic absorption spectrometry GB/T4372.5-2001 Standard download decompression password: www.bzxz.net

GB/T4372.5—2001
This standard is a revision of GB/T4372.4—1984 "Zinc Oxide (Direct Method) Chemical Analysis Method Potassium Periodate Photometric Determination of Manganese Content". The main content of the revision is the determination of manganese content by atomic absorption spectrometry. This standard complies with:
GB/T1467-1978 General Principles and General Provisions of Metallurgical Product Chemical Analysis Methods GB/T7728--1987 General Principles of Flame Atomic Absorption Spectrometry for Chemical Analysis of Metallurgical Products GB/T17433-1998 Basic Terminology for Chemical Analysis of Metallurgical Products This standard will replace GB/T4372.4—1984 from the date of implementation. This standard is proposed by China Nonferrous Metals Industry Association. This standard is under the jurisdiction of China Nonferrous Metals Industry Standard Metrology and Quality Research Institute. This standard is drafted by Shuikoushan Mining Bureau. The main drafters of this standard are Zhang Jiangfeng and Zeng Guangming. This standard is entrusted to the National Technical Committee for Standardization of Nonferrous Metals for interpretation. 127
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of zinc oxide produced by direct process
Determination of manganese content by atomic absorption spectrometry
Methods for chemical analysis of zinc oxide produced by direct process-Determination of zinc oxide manganese content-Atomic absorption spectrometry method This standard specifies the method for the determination of manganese content in zinc oxide produced by direct process. GB/T 4372.5—2001
Replaces GB/T4372.4-1984
This standard is applicable to the determination of manganese content in zinc oxide produced by direct process. Determination range: 0.00005%～0.0010%. 2 Summary of the method
The sample is dissolved in nitric acid, and iron hydroxide is used as a carrier to co-precipitate and separate zinc and enrich trace manganese (samples with a mass fraction of manganese greater than 0.0003% can be directly determined). In a dilute nitric acid medium, measure the absorbance of manganese at a wavelength of 279.5nm on an atomic absorption spectrometer. 3 Reagents
3.1 Ammonium persulfate. bzxZ.net
3.2 Nitric acid (1+1).
3.3 Nitric acid (1+9).
3.4 ​​Hydrogen peroxide-nitric acid mixture: Add 5mL hydrogen peroxide to 100mL nitric acid (3.3). 3.5 Ferric chloride solution: Weigh 1.43g ferric oxide (high purity) into a 300ml beaker, moisten with water, add 30ml hydrochloric acid, and after complete dissolution, transfer to a 500mL volumetric flask, wash the beaker with water several times, add it to the volumetric flask, dilute to the mark with water, and mix well. This solution contains 2.0mg iron per ml.
3.6 Manganese standard stock solution: Weigh 0.1000g of high-purity metallic manganese into a 300mL beaker, moisten with water, add 20mL of nitric acid (3.2), heat to dissolve, cool and transfer to a 1000mL volumetric flask, dilute to scale with water, and mix. This solution contains 100μg of manganese per mL. 3.7 Manganese standard solution: Transfer 2.50mL of manganese standard stock solution (3.6) into a 100mL volumetric flask, dilute to scale with water, and mix. This solution contains 2.5μg of manganese per mL.
4 Instruments
Atomic absorption spectrometer with manganese 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 measured sample solution, the characteristic concentration of manganese should not be greater than 0.3ug/mL. Precision: When the absorbance is measured 10 times with the highest concentration standard solution, the 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), the standard deviation should not exceed 0.5% of the average absorbance of the highest concentration standard solution.
Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on 2001-07-10 128
Implemented on 2001-12-01
GB/T4372.52001
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 0.85.
See Appendix A (Instructions) for instrument working conditions. 5 Analysis steps
5.1 Test materials
Weigh the sample according to Table 1 to an accuracy of 0.0001g. Table 1
Mass fraction of manganese, %
0.000 05~0. 000 3
≥0. 000 3 ~ 0. 001 0
5.2 Blank test
Carry out a blank test together with the sample.
5.3 Determination
Sample amount, g
5.3.1 Place the sample (5.1) in a 300mL beaker, moisten with water, add 5mL ferric chloride solution (3.5), slowly add 20mL nitric acid (3.2), shake well, heat on an electric furnace to dissolve, boil for 1min, and cool. 5.3.2 Carefully neutralize with ammonia water until the generated zinc hydroxide precipitate is completely dissolved and a brown ferric hydroxide precipitate is generated. After boiling, add about 0.2g of ammonium persulfate (3.1), boil for another 5min~10min, remove and add 1mL~2mL of ammonia water, filter with fast filter paper while hot, and wash the beaker and precipitate with 2% hot ammonia solution 4 times. 5.3.3 Use hot hydrogen peroxide-nitric acid mixture (3.4) to dissolve the precipitate in a 25mL volumetric flask, cool, dilute with water to scale, and mix well.
5.3.4 Place the test solution at a wavelength of 279.5nm on an atomic absorption spectrometer, adjust to zero with water at the same time as the series of standard solutions, measure its absorbance, subtract the absorbance of the blank test solution, and find the corresponding manganese concentration from the working curve. Note: For samples with a mass fraction of manganese greater than 0.0003%, place the sample in a 100mL beaker, moisten with water, add 5mL of nitric acid (3.2) and heat to dissolve, cool and transfer to a 25mL volumetric flask, dilute with water to scale, and mix well. The following is carried out according to step 5.3.4. 5.4 Drawing of working curve
5.4.1 Pipette 0, 1.00, 2.00, 3.00, 4.00, 5.00mL of manganese standard solution (3.7) into a 25mL volumetric flask, add 12.5mL of nitric acid solution (3.3), dilute to the scale with water, and mix well. 5.4.2 Under the same conditions as the test solution, measure the absorbance of the series of standard solutions, subtract the absorbance of the zero concentration solution in the series of standard solutions, and draw the working curve with manganese concentration as the horizontal axis and absorbance as the vertical axis. 6 Expression of analysis results
Calculate the mass fraction of manganese according to formula (1):
w(Mn) V× 10 × 100
Wherein: z(Mn) mass fraction of manganese, %; C——manganese concentration obtained from the working curve, ug/mL; V—volume of the measurement solution, mL;
m----mass of the sample, g.
7 Allowable difference
The difference in analysis results between laboratories should not be greater than the allowable difference listed in Table 2. (1)
Mass fraction of manganese
0. 000 05~0. 000 30
>0. 000 30 ~ 0. 001 00
GB/T 4372. 5—2001
Allowance
GB/T4372.5—2001
Appendix A
(Suggestive Appendix)
Instrument working conditions
The working conditions for measuring manganese using GGX-5 atomic absorption spectrophotometer are shown in Table A1. Table A1
Wavelength, nm
Lamp current, mA
Monochromator passband, nm
Air flow, t/min
Bene flow, L/min
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