Determination of uranium in phosphoric acid using 4-(2-pyridylazo)-resorcinol and 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol reagents

Abstract

An extraction-spectrophotometric procedure for the determination of uranium in phosphoric acid is described. It is based on the extraction of uranium with trioctylphosphine oxide in cyclohexane and subsequent reaction with 4-(2-pyridylazo)resorcinol or 2-(5-bromo-2-pyridylazo)-5-diethylaminophenol, both of which are highly sensitive reagents that produce stable complexes. The determination of uranium in different stages of its extraction from wet-process phosphoric acid and in phosphate rocks, gypsum and water has been successfully carried out using the described procedures and reagents.