Weathered crust elution - deposited rare earth ore (original name is the ion-adsorbed rare earth ore) was first discovered as a novel exogenous ore in Jiangxi province of China in 1969. There are many advantages for the ore which has a widespread distribution, rich reserves, low radioactivity, complete RE partitioning and is rich in middle and heavy rare earth. Especially, the middle and heavy rare earth which occupies 80% over the world is the unique mineral resource in China, distributing only in southern China such as Jiangxi, Fujian, Hunan, Guangdong and Guangxi et al.
Since weathered crust elution - deposited rare earth ore was discovered, the basic researches on the metallogeny mechanism, the prospecting rule and the production have been studied continuously for more than thirty years. The three leaching technologies of bath leaching with sodium chloride, bath leaching with ammonium sulfate and in-situ leaching with ammonium sulfate are developed sequentially. All of these contribute to the industry of the weathered crust elution-deposited rare earth ore. However, there was no systematic work on the weathered crust elution - deposited rare earth ore in the past due to many reasons such as the confidentiality, which was not beneficial for the development of this ore. The metallogeny theory and mining technologies of the weathered crust elution - deposited rare earth ore are introduced systematically in this book for readers.