This standard specifies the determination method of zinc oxide content in direct zinc oxide. This standard is applicable to the determination of zinc oxide content in direct zinc oxide. Determination range: ≥98.0%. GB/T 4372.1-2001 Direct zinc oxide chemical analysis method Na2 EDTA titration method for determination of zinc oxide content GB/T4372.1-2001 Standard download decompression password: www.bzxz.net

GB/T 4372. 1—2001
This standard is a revision of GB/T4372.1-1984 "Zinc Oxide (Direct Method) Chemical Analysis Method Potassium Ferrocyanide Volumetric Method for Determination of Zinc Oxide Content". The main content of the revision is to use the Na?EDTA titration method to determine the amount of zinc oxide, and to use the combined masking method to solve the interference of lead and cadmium on the titration.
This standard complies with:
GB/T1467--1978 General Principles and General Provisions for Chemical Analysis Methods for Metallurgical Products GB/T17433-1998 Basic Terminology for Chemical Analysis of Metallurgical Products This standard will replace GB/T4372.1--1984 from the date of implementation. This standard was proposed by the China Nonferrous Metals Industry Association. This standard is under the jurisdiction of the China Nonferrous Metals Industry Standard Metrology and Quality Research Institute. This standard was drafted by the Shuikoushan Mining Bureau. The main drafters of this standard are: Zeng Guangming, Bao Binghui, Ling Zongyu, and Ling Shaoyue. This standard is entrusted to the National Technical Committee for Standardization of Nonferrous Metals for interpretation. 111
1 Scope
National Standard of the People's Republic of China
Chemical analysis method of zinc oxide produced by direct process
Determination of zinc oxide content by Na2EDTA titration method
Methods for chemical analysis of zinc oxide produced by direct process--Determination of zinc oxide content-Na2 EDTA titration method
This standard specifies the method for determining the zinc oxide content in zinc oxide produced by direct process. GB/T4372.1-2001
Replaces GB/T4372.1—1984
This standard applies to the determination of zinc oxide content in zinc oxide produced by direct process. Determination range 98:0%. 2 Method Summary
The sample is dissolved in dilute sulfuric acid. In a pH 5-6 hexamethylenetetramine-sulfuric acid buffer solution, potassium iodide is added to mask cadmium, sodium sulfite is added to mask lead, and xylenol orange is used as an indicator. The NazEDTA standard solution is titrated until a bright yellow color is the end point. 3 Reagents
3.1 Ascorbic acid.
3.2 Standard zinc oxide.
3.3 Sulfuric acid (1+3).
3.4 ​​Ammonia water (1+1).
3.5 Hexamethylenetetramine-sulfuric acid buffer solution (pH 5~6): Weigh 300g hexamethylenetetramine in a 2000mL beaker, add 950mL water to dissolve (if the solution is red, filter it with cotton), then add 50mL sulfuric acid (1+1), and mix. 3.6 Sodium sulfite solution: weigh 30g of anhydrous sodium sulfite and dissolve it in 200mL of water, add 50mL of sulfurous acid, and control the pH to about 6 (valid for the day).
3.7 Potassium iodide solution (200g/L): weigh 20g of potassium iodide and dissolve it in 100ml of water, add a little ascorbic acid until the yellow color fades away. 3.8 Methyl red solution (1.0g/L).
3. 9 Dimethylol orange solution (2 g/L).
3.10 Disodium ethylenediaminetetraacetic acid standard solution (0.06 mol/L) 3.10.1 Preparation: weigh 228.7g of disodium ethylenediaminetetraacetic acid, add water to dissolve it under slight heat, cool it to room temperature, transfer it to a 10000mL volumetric flask, add water to dilute to the scale, and mix it thoroughly. Calibrate it after three days of deafness. 3.10.2 Calibration: Weigh 0.50000g (accurate to 0.02mg) of three portions of standard zinc oxide (3.2) (burned in porcelain blood at 800C for 2h3h before use) into a 300ml beaker and calibrate according to analysis step 6.3. Take the average value. If the difference does not meet the requirements, recalibrate. Perform a blank test at the same time.
Calculate the actual concentration of disodium ethylenediaminetetraacetic acid standard solution (3.10) according to formula (1): Approved by the General Administration of Quality Supervision, Inspection and Quarantine of the People's Republic of China on July 10, 2001 112
Implementation on December 1, 2001
In the formula: c
GB/T 4372.1--2001
= (VV) × 0. 081 37
Actual concentration of disodium ethylenediaminetetraacetic acid standard solution (3.10), mol/L; mMass of standard zinc oxide, g;
V——Volume of Na,EDTA (3.10) standard solution consumed during calibration, mL; V. ——The volume of Na2EDTA (3.10) standard solution consumed in titrating the blank test solution during calibration, mI; (1)
0.081 37—The molar mass of zinc oxide equivalent to 1.00 mL of disodium ethylenediaminetetraacetic acid standard solution [c(Ci.H14N,OgNa2·2H,O)=1.000 mol/L}, g/mol
The average of the three calibration results is the actual concentration of disodium ethylenediaminetetraacetic acid standard solution (3.10). The extreme difference of the volume of disodium ethylenediaminetetraacetic acid standard solution consumed in parallel calibration should not exceed 0.10 mL. Otherwise, recalibrate. 4 Instruments
4.1 The sensitivity of the microanalytical balance is 0.01 mg. 4.2 Fat-bellied burette 100.00 mL, 97.00 mL~100.00 mL (scale value is 0.02 mL). 4.3 Electromagnetic stirrer (with rotor).
5 Sample
The sample is dried at 105℃～110℃ for 2h in advance, placed in a desiccator and cooled to room temperature. 6 Analysis steps
6.1 Sample
Weigh 0.50000g sample, accurate to 0.00001g. 6.2 Blank testwww.bzxz.net
Perform a blank test with the sample.
6.3 Determination
6.3.1 Place the sample (6.1) in a 300mL beaker, moisten with water, add 10mL sulfuric acid (3.3), cover, and heat slightly until completely dissolved. Remove and cool slightly, wash Table III and the wall of the beaker with water.
6.3.2 Add 1 drop of methyl red (3.8), neutralize with ammonia water (3.4) to yellow, then neutralize with sulfuric acid (3.3) to red, and wash the wall of the beaker with water. 6.3.3 Add 20 mL of hexamethylenetetramine-sulfuric acid buffer solution (3.5), 12.5 mL of sodium sulfite solution (3.6), 20 mL of potassium iodide solution (3.7), 0.1 g of ascorbic acid (3.1), 2 to 3 drops of xylenol orange indicator (3.9), and a stirring bar. Stir continuously on an electromagnetic stirrer and titrate with disodium ethylenediaminetetraacetic acid standard solution. When the standard solution drops to the microscale, add slowly until it turns bright yellow.
7 Description of analysis results
Calculate the mass fraction of zinc oxide according to formula (2): w(ZnO) = (Vi-Vo) × 0. 081 37)m
Wherein: c-
Actual concentration of Na2EDTA standard solution (3.10), g/L; × 100
Volume of Na2EDTA (3.10) standard solution consumed when titrating the test solution, mL; V. -Volume of Na2EDTA (3.10) standard solution consumed in the blank test, mL, m
Mass of the sample, g,
Molar mass of zinc oxide equivalent to 1.00mL disodium ethylenediaminetetraacetic acid standard solution [c(CioHt,N,OgNa2·2H2O)=1.000mol/L], g/mol.
Allowance
GB/T4372.1--2001
The difference between the analysis results of laboratories should not be greater than the allowance listed in Table 1. Table 1
Mass fraction of zinc oxide
Allowance
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