The preparation of anhydrous lanthanon chlorides by high‐temperature chlorination of monazite

Abstract

The reaction between monazite, chlorine and carbon has been investigated at temperatures above the melting point of the mixed lanthanon chlorides. Conditions have been established, on a laboratory scale, for recovering over 85 9, of the lanthanons as anhydrous chlorides. At temperatures over 900" c. these are virtually free of thorium chloride and phosphorus compounds, which volatilize together with impurities such as iron, aluminium, chromium and titanium chlorides.The nature of the volatile products has been examined and particular reference is made to the evolution of elementary phosphorus. The thermodynamics and mechanism of the reactions have been discussed.