GB/T 4372.1-2014 Methods for chemical analysis of zincoxide produced by direct process—Part 1:Determination of zinc oxide content—Na2EDTA titration method
Methods for chemical analysis of zinc oxide produced by direct process -
Part 1: Determination of zinc oxide content - Na2EDTA titration method
1 Scope
This part of GB/T 4372 specifies the methods for determining the zinc oxide content of zinc oxide produced by direct process.
This part is applicable to the determination of zinc oxide content of zinc oxide produced by direct process, with the determination range ≥ 98.00%.
2 Method summary
Dissolve the specimen with dilute sulfuric acid, add potassium iodide into the hexamethylene tetramine-sulfuric acid buffer solution with a pH of 5~6 to mask the cadmium, add sodium sulfite to mask the lead and, taking xylenol orange as the indicator, titrate with Na2EDTA standard solution until the solution takes on bright yellow.
3 Reagents
Unless otherwise specified, only the recognized analytical reagents and distilled water or deionized water or water with equivalent purity shall be used during the analysis.
3.1 Ascorbic acid.
3.2 Reference zinc oxide (ωZnO≥99.999%): ignite at 800℃ for 2 h~3 h before use, take it out and cool it to ambient temperature in a desiccator.
3.3 Sulfuric acid (ρ 1.84 g/mL).
3.4 Ammonia.
3.5 Sulfuric acid (1+3).
3.6 Ammonia (1+1).
3.7 Hexamethylene tetramine-sulfuric acid buffer solution (pH of 5 to 6): weigh 300 g of hexamethylenetetramine in a 2,000mL beaker, add 950 mL of water to dissolve it (if the
