ISOLATION AND DETERMINATION OF MINUTE AMOUNTS OF RARE EARTHS METALS IN ROCKS AND MINERALS

A method is suggested for the isolation and determination of minute amounts of rare earth metals in rocks and minerals. The sample is processed with acids, then the rare earth metals, together with the accompanying metals, are co- precipitated from the solution by ammonia, and the filtered precipitate is converted into oxides by ignition. The oxides obtained in this way are subjected to chlorinntion under prescribed conditions, and the rare earth metals are determined in the residue with the aid of arsenazo'' in the presence of sulphosalicylic acid in a hexamethylenetetramine buffer. (auth)