Amperometric Titration Method for Thorium in Presence of Rare Earths of Monazite Sand

Abstract

A suitable method for the volumetric determination of thorium in the presence of Interfering substances has not been available. An amperometric method is described which utilizes ammonium molybdate as titrant. The procedure permits the determination of 10 to 30 milligrams of thorium oxide in the presence of up to 800 milligrams of rare earth oxides in a volume of 50 milliliters. Thorium and the rare earths must be present as chloride. Perchlorate, nitrate, and sulfate ions should be excluded. This titrimetric procedure allows a rapid and accurate determination of thorium in the presence of moderately large quantities of rare earths such as in monazite sand.