从原子序数57的镧(La)到71的镥(Lu)的镧系元素加上原子序数39钇(Y)和原子序数21的钪(Sc)统称为稀土元素。稀土电子结构为Sc:3S~2 3P~6,Y:4S~2 4P~6,镧系元素:5S~2 5P~6,其外层电子结构相同都为S~2P~6。镧系元素具有的特点是内层的4f电子随着原子序数的增加而有规则成正比地增加。因而,稀土元素化学性质彼此很相似,稀土各元素单体分离极为困难。近年来,稀土用作荧光体材料、磁性材料、热中子吸收材料或超导原材料等的功能性原材料而倍受重视。稀土功能性原材料的特性是由各个单一元素特有的物理性质决定。稀土的分离和提纯随着科学技术的发展 Lanthanides from lanthanum (La) of atomic number 57 to lanthanum (Lu) of 71 and scandium (Sc) having atomic number 39 of yttrium (Y) and atomic number 21 are collectively referred to as rare earth elements. The electronic structures of rare earths are Sc: 3S ~ 2 3P ~ 6, Y: 4S ~ 2 4P ~ 6, and lanthanides: 5S ~ 25P ~ 6. The electronic structures of the rare earths are all S ~ 2P ~ 6. Lanthanides have the characteristic that the inner 4f electrons increase regularly and proportionally with the atomic number. Thus, the chemical properties of rare earth elements are very similar to each other, the separation of rare earth elements is extremely difficult. In recent years, rare earth is used as a functional material such as a phosphor material, a magnetic material, a thermal neutron absorbing material, or a superconducting raw material. The properties of rare earth functional raw materials are determined by the unique physical properties of individual elements. Rare earth separation and purification with the development of science and technology