Rapid Volumetric Determination of Zirconium in Ferro-Zirconium Alloys with Cupferron

Abstract

A simple and rapid procedure for the volumetric determination of zirconium in feno-zirconium alloys has been investigated. Zirconium can be titrated directly with standard cupferron solution using iron (III) as indicator. The titration is carried out in a 25% sulfuric acid solution containing iron (III) and ethyl ether, and after the reaction between zirconium and cupferron is complete, iron (III) is precipitated with cupferron as ferric cupferrate. The end point of titration can be detected by color change of ethyl ether layer with ferric cupferrate in the presence of precipitate of zirconium cupferrate. This simple procedure has only few interferences, and can usually be applied with a minimum preliminary treatment after dissolving the sample in sulfuric acid and ammonium flouride, which are efficient solvents for ferro-zirconium alloys. Flouride interferes in this method but can be removed easily by fuming with sulfuric acid and boric acid.