As early as 1992, Deng Xiaoping mentioned during his southern tour: "There is oil in the Middle East, and rare earths in China," which expressed the status of China's rare earth resources. Most people who are not familiar with rare earths may wonder how rare earths have become strategic resources comparable to oil? What is rare earth? Rare earth is a general term for the seventeen metal elements in the periodic table, including lanthanide elements, scandium, and yttrium