Separation of small amounts of thorium from the cerite earths of monazite and other elements. Use of cinnamic acid

Abstract

Cinnamic acid has been found to be a suitable reagent €or the estimation and separation of small amounts of thorium from the cerite earths of monazite. The latter in concentration upto 2000 fold may be conveniently separated in a single precipitation. Using this reagent a separation from other common elements may also be effected. The presence of a little nitric acid (about N/100) in the wash liquid is found useful in giving separations described particularly when dealing with relative1 y Iarge amounts of the cerite earths.The use of cinnamic acid as a reagent for the estimation of thorium and its separation from the cerite earths of monazite has been reported previously 1) and conditions have been given for the separation of thorium from about a fifty fold excess of the latter in a single operation. This communication describes a modification which enables estimation of micro quantities of thorium and its separation from large quantities of cerite earths, in fact cerite earths may well be rendered free from thorium. Interference from a variety of cations has also been investigated. E x p e r i m e n t a l .Reagents. Thorium nitrate.Thorium Nitrate (B.D.H.) reagent grade was further purified as described in a previous communication2). A stock solution containing 3.02 mg per 100 ml was prepared and used throughout the investigation.