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稀土元素一般分为经分离过的高纯稀土和未完全分离的混合稀土。表1示出稀土元索及其原子量,但除这17种元素外还要加进锕(Ac)。 1794年在瑞典的矿石中发现了称做“钇”的稀土元素,此后又发现了各种各样与其同类的元素,命名为稀土族元素。然而现在从稀土元素在地壳中的含量来看,在地球上蕴藏有意想不到的大量的稀土元素(参见表2)。例如,铈比锡还多,钇比铅还多。但集中的矿藏还未发现,且因炼制、分离很困难,还没得到大量应用。然而在原子能领域中,若把作为核燃料的铀、钍等矿石进行反复多次
Rare earth elements are generally divided into high purity rare earth separated and not completely separated mixed rare earth. Table 1 shows the rare earth elemental cords and their atomic weights, but in addition to these 17 elements also added actinium (Ac). In 1794, a rare earth element called “yttrium” was found in the ores of Sweden. Since then, a variety of similar elements have been discovered, named rare earth elements. Now, however, the content of rare earth elements in the earth’s crust contains an unexpectedly large amount of rare earth elements (see Table 2). For example, there are more cerium than tin and more yttrium than lead. However, the concentrated mineral deposits have not been discovered yet, and because of the difficulty of refining and separation, they have not been widely used. However, in the field of atomic energy, if uranium, thorium and other minerals as nuclear fuel are repeated many times