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What is heavy rare earth?
- Mar 16, 2018 -

According to the physical and chemical properties and geochemical properties between rare earth elements and separation process requirements, some of the differences scholars tend to rare earth elements are divided into light and heavy two groups or light, medium, heavy three group. The division of the two groups takes gadolinium as the boundary. The former lanthanum, dysprosium, cerium, praseodymium, neodymium, promethium, samarium and europium are light rare earth elements, also known as cerium group. After gadolinium and gadolinium, nine elements such as terbium, dysprosium, holmium, erbium, thulium, ytterbium, luteum and yttrium are called heavy rare earth elements, also known as yttrium group. Although the atomic weight of yttrium is only 89, its chemical properties are closer to heavy rare earth elements due to its ion radius in the ion radius link of other heavy rare earth elements. In nature, it is also associated with other heavy rare earth elements. Therefore, it is classified as a heavy rare earth group. There are no definite rules for the classification of the three groups of rare earths in light weight. For example, the solubility of the rare earth sulfate complex is divided into: the refractory cerium group is the light rare earth group, including lanthanum, cerium, praseodymium, neodymium and samarium. Microlytic terbium group, including europium, gadolinium, terbium and dysprosium; The more soluble yttrium group is the heavy rare earth group, including yttrium, holmium, erbium, thulium, ytterbium and lutetium. However, the solubility difference between adjacent elements in each group is very small, which is not clear in this way. Now, multi-purpose extraction is used for grouping, for example, two (2) ethyl hexyl (phosphoric acid), P204, can be grouped in neodymium/samarium and then in gadolinium/terbium. They are called light rare earth, samarium, europium, gadolinium, which is called rare earth, terbium, dysprosium, holmium, erbium, thulium, ytterbium, lutetium and yttrium.