Sequential determination of free acidity and hydrazine in presence of hydrolysable ions

Abstract

Free acidity / Hydrazine / EDTA / Formaldehyde / pH 3.0 / Sodium carbonate / Purex process Summary. A simple method for the sequential determination of free acidity and hydrazine in presence of hydrolysable ions is developed and described. In this method, free acid is titrated with standard sodium carbonate solution after the metal ions in solutions are masked with EDTA. Once the end point for the free acid is determined at pH 3.0, an aliquot of formaldehyde is added to liberate the acid equivalent to hydrazine which is then titrated with the same standard sodium carbonate solution using an automatic titration system. The described method is simple, accurate and reproducible. This method is especially applicable to all ranges of nitric acid and heavy metal ion concentration relevant to Purex process used for nuclear fuel reprocessing. The overall recovery of nitric acid is 98.9% with 3% relative standard deviation. The major advantage of the method is that it uses sodium carbonate a primary standard as titrant and generation of corrosive analytical wastes containing oxalate or sulphate is avoided. Valuable metals like uranium and plutonium can easily be recovered from analytical waste before final disposal.

Developed New Procedure for Low Concentrations of Hydrazine Determination by Spectrophotometry: Hydrazine-Potassium Permanganate System

“…Accordingly, their determination at the micro level is of great importance. Despite the accuracy of most of the redox methods [9,10] used for the determination of hydrazines, only few are suitable for extremely dilute solutions, and some require carefully controlled conditions. Most of the spectrophotometric procedures available so far in the literatures [11][12][13][14][15][16][17][18][19][20][21][22] are tedious and involve the use of rare and expensive colour reagents.…”