摘要:Rare earth elements were discovered consecutively from the end of 18th century.The researches on the preparation of rare earth metal starts was carried out gradually at the beginning of the 19th century.After more than 100 years of improvements,preparation technology of 17 kinds of rare earth metals was completed by the middle of the 20th century.
关键词:EARTHEARTHPREPARATION
分类号: F42[经济管理—产业经济]