This standard specifies analytical methods for copper and iron in steam and water in fossil fuel power plants using stripping voltammetry polarography.
This standard is applicable to the determination of copper and iron in boiler feed, condensed water, steam, generator cooling water and boiler water, etc. The detection range is 0~100μg/L for copper and 0~100μg/L for iron.
2 Normative References
The following referenced documents are indispensable for the application of this document. For dated reference, only the edition cited applies. For undated references, the latest edition of the normative document (including any amendment) applies.
GB/T 6903 "Analysis of Water Used in Boil and Cooling System - General Rule"
GB/T 6907 "Analysis of Water used in Boil and Cooling System - The Sampling Method of Water"
3 Method Summary
Under certain buffer condition and reduction potential, the copper and iron in the solution are reduced on the hanging mercury electrode, on which the homojunction metal is oxidized into appropriate metal ions into the solution by applying inverse voltage. The content of copper and iron in the sample is calculated by using the current generated by oxidation process.
4 Reagents
4.1 Reagent water: shall comply with Grade I reagent water specified in GB/T 6903.
4.2 Reagent purity: shall comply with GB/T 6903.
4.3 Hydrochloric acid: (1+1), prepared with hydrochloric acid of guaranteed reagent.
4.4 Nitric acid: (1+1), prepared with nitric acid of spectral reagent or guaranteed reagent.
4.5 Sulfuric acid: (1+2), prepared with sulfuric acid of spectral reagent or guaranteed reagent.
4.6 PH=4.6 buffer solution: transfer 11.4mL glacial acetic acid of guaranteed reagent into a 100mL volumetric flask filled with about 50mL reagent water and add 7.5mL of ammonia water of guaranteed reagent and scale the volume by reagent water for future use.
4.7 Ammonia water: (1+1), prepared with ammonia water of spectral reagent or guaranteed reagent.
