稀土 单个稀土金属及其氧化物中稀土含量的测定 滴定法

[中文适用范围]： 本文件规定了测定15种单个稀土金属（镧、铈、镨、钕、钐、铕、钆、铽、镝、钬、铒、铥、镱、镥和钇）及其氧化物中稀土含量的滴定法。稀土含量的测定范围（质量分数）如下：——稀土金属：98.0％（质量分数）～99.5％（质量分数）；——稀土氧化物：95.0％（质量分数）～99.5％（质量分数）。本标准不适用于下列单个稀土金属及其氧化物：a）稀土相对纯度（质量分数）小于99.5％； b) 各种（非稀土）金属元素的总含量按质量分数大于 0.5%； c) 钍、钪或锌的含量按质量分数大于 0.1%。 [外文原描述]： This document specifies a titration method for the determination of rare earth content in 15 kinds of individual rare earth metals (lanthanum, cerium, praseodymium, neodymium, samarium, europium, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium) and their oxides. The determination ranges for the rare earth content in mass fraction are as follows: — rare earth metal: 98,0 % (mass fraction) to 99,5 % (mass fraction); — rare earth oxide: 95,0 % (mass fraction) to 99,5 % (mass fraction). It does not apply to individual rare earth metals and their oxides when: a) the 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.