Mineral evolution and separation of rare-earth phases from Bayan Obo rare-earth concentrate in a super-gravity field

Abstract

Rare-earth concentrate obtained through mineral processing of rare-earth ore was characterized by a high rare-earth content and various rare-earth minerals. To effectively recover rare earth from the rare-earth concentrate, a novel method of enriching rare-earth elements and separating the RE-rich phases from Bayan Obo rare-earth concentrate by super gravity was proposed in current study. The mineral evolutions of rare-earth phases and the migrations of rare earth in various phases with temperature rising were investigated. The variations of mineralogical compositions and microstructures indicated the rare-earth phases transformed into fine britholite, cerium oxyfluoride, rare-earth ferrate and monazite particles at a low temperature range of 1423 K–1523 K, which transformed further into lager equiaxed cerium oxyfluoride crystals and most rare-earth elements enriched into the cerium oxyfluoride phase significantly at a higher temperature range of 1573 K–1773 K. Consequently, separation of the RE-rich phases was carried out at the high temperature range in a super-gravity filed, and the cerium oxyfluoride phase and the britholite containing slag phase were effectively separated by super gravity.