scope:

This document specifies a titration method for the determination of rare earth contents in 15 kinds of individual rare earth metal (lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium) and their oxides. It is applicable to the 15 individual rare earth metals with rare earth content (defined in 3.1) between 98,0 % and 99,5 % in mass fraction. It is also applicable to the 15 individual rare earth oxides with rare earth oxide content between 95,0 % and 99,5 % in mass fraction. It is not applicable to those individual rare earth metals and their oxides in following cases: a) Relative rare earth purity is less than 99,5 % in mass fraction. b) The total content of various (non-rare earth) metallic elements is greater than 0,5 % in mass fraction. c) The content of thorium, scandium or zinc is greater than 0,1 % in mass fraction.