Determination of zirconium and vanadium in niobium base alloys

The procedure of direct complexonometric titration of zirconium (more than 5%) in niobium base alloys has been developed. Titration is performed in approximately 0.7 N H2SO4 in the presence of peroxide complexes of niobium, tungsten, and molybdenum. The duration of one determination run is one hour. The procedure is described of titrimetric determination of vanadium (more than 3%) in niobium-base alloys. The titrimetric method is based on V(5) reduction with the Mohr salt solution, subsequent oxidation of bivalent iron excess with ammonium persulphate, and titration of reduced V(4) with potassium permanganate. The relative standard deviation is 0.004; duration of one determination run is 1.5 h