Chapter 5 - Rare Earths Purification, Separation, Precipitation and Calcination

Abstract

This chapter describes production of pure, marketable individual rare earth compounds from Chapter 4's impure mixed rare earth carbonate precipitate feed. As applied to rare earths the production of pure individual rare earth compounds entail: (i) leaching Chapter 4's impure mixed rare earth precipitate; (ii) purifying the resultant solution from non rare earth impurities and in particular from radioactive elements; (iii) producing individual pure rare earth solutions ; (iv) precipitating rare earth compounds from these purified leach solutions and (v) calcining these precipitated compounds to produce marketable rare earth oxides, phosphates and fluorides. In 2014, virtually all industrial rare earth separations are done by solvent extraction. The success of solvent extraction in separating rare earths is based in the best compromise compared to other processes for operating costs and capital expenditure.