A review of the beneficiation of rare earth element bearing
The challenge of the REE supply due to the scarcity of mineral deposits is aggravated by the fact that the elements are never found in an equal or even predictable distribution Gupta and Krishnamurthy 1992 The REE crustal abundance as depicted in Fig 2 also demonstrates the Oddo Harkin s rule which states that elements with even atomic numbers are significantly more prevalent in the