Methode for chemical analysis of iron,steel and alloy The carrier precipitation-molybdenum blue potometric method for the determination of antimony content
1 Subject Content and Application Scope
This Standard specifies a carrier precipitation-molybdenum blue potometric method for the determination of antimony content.
This Standard is applicable to the determination of antimony content in carbon steel, alloy steel, high temperature alloy, precision alloy and cast iron. Determination range: 0.0003%~0.10%.
2 Principle
In nitric acid medium, manganese peroxide is adopted as carrier to precipitate antimony so as to separate it from large amount of iron, chromium, nickel, cobalt, aluminum, copper, etc.. Filter to eliminate wolfram in advance. Niobium and titanium cause interference; with the existence of tartaric acid in sulphuric acid solution, methyl isobutyl ketone is adopted to extract coordination compound formed by antimony and iodine ion so as to separate antimony from niobium and titanium. Antimony and phosphorus-molybdenum heteropoly acid form coordination compound in sulphuric acid solution; butylacetate is adopted for extracting; measure the absorbance.
Determination will not be interfered when the contents of the metals in color solution is less than the corresponding contents listed below: 250 mg of manganese (II), 100 mg of iron (II), 300 mg of nickel (II), 30 mg of chromium (VI), 0.1 mg of titanium (IV), 10 mg of aluminum (III), 2 mg of copper (II), 5 mg of cerium (IV), 0.5 mg of zinc (II), 1.0 mg of bismuth (III), 0.5 mg of tin (IV), 1000 mg of sodium (I), 1500 mg of ammonium ion.
