1 Scope

This document describes procedures for the determination of non-rare earth impurities in individual rare earth metals and their oxides through the use of inductively coupled plasma atomic emission spectroscopy (ICP-AES). Magnesium (Mg), aluminum (Al), silicon (Si), calcium (Ca) and iron (Fe) are included as non-rare earth impurity elements, and the measurement ranges for each impurity element are specified. The applicable measurement range (mass fraction %) of magnesium, aluminum, silicon and calcium is from 0,001 to 0,2, and that of iron is from 0,001 to 0,5. The verified measurement ranges in the interlaboratory tests are described later in this document.