Chapter 1 - Extraction of Rare Earths From RE Concentrates

Abstract

The processes of extracting rare earths from the concentrates, which are currently applied in rare earth industry, consist of decomposition, leaching, impurity removing, and concentrating or caustic conversion into rare earth chlorides and other steps. Decomposition of rare earth minerals in the concentrates, including sodium hydroxide solution, oxidization roasting, intensified roasting with sulfuric acid, and roasting with sodium carbonate, is to convert rare earths into their soluble forms of mineral acids; leaching by acids is to dissolve rare earths into acidic solution for the separation of rare earths with most of the impurities; impurity removing is to further purify rare earth solution by using various ways to separate small amount of impurities in the solution for preparation of feed of solvent extraction separation or production of mixed rare earth chlorides. This chapter systematically discusses the various processes of extracting rare earths from different rare earth concentrates including monazite, bastnaesite concentrates, mixed rare earth concentrate of bastnaesite and monazite, and ion-absorptive rare earth concentrate with main process parameters and flow sheets used in actual rare earth industry and provides readers with the basic technologies and options of the processes to understand, design, and develop effective, efficient, and economical processes of extracting rare earths from different rare earth concentrates.