A simple apparatus for separating fluorine from aluminosilicates by pyrohydrolysis

Abstract

Fluorine-bearing minerals are hydrolysed at 700° to 800° C in a gasheated fused-silica tube. The hydrogen fluoride evolved is absorbed in alkali and determined by titration with thorium nitrate or absorptiometrically with cerium-alizarin complexone. Recoveries from sodium fluoride averaged 98·6 per cent., with a coefficient of variation of 3·2 per cent., and the determined fluorine contents of the silicate rock standards GSP–1 and G2 were 0·381 and 0·134 per cent. The method is simple and rapid, and is suitable for determining fluorine in micas and related aluminosilicates.