Characterisation of heavy mineral concentrates in sands from the Hongcheon River,South Korea

Abstract

A river sand sample from the Hongcheon River was magnetically fractionated to concentrate heavy minerals to determine the potential of the river for the recovery of valuable minerals. Separate magnetite/haematite-rich, ilmenite-rich, monazite-rich and zircon-rich fractions were characterised using chemical, X-ray and electron beam techniques. The magnetite particles were high-grade (93.7wt% Fe₂O₃), fully liberated and with minor or trace amounts of Mn, Mg, and Al. The ilmenite contained, on average, 53.6% Fe₂O₃ and 50.8% TiO₂ and mineral impurities in the fraction included garnet, olivine, and magnetite, present as discrete grains. Two populations of monazite grains were found (Ce-rich and Th-rich), both dominated by LREEs. The zircon fraction contained ∼70% zircon particles with impurity phases including titanite and fluorapatite. Characterisation of the concentrates showed that the ilmenite could be commercially processed but further refinement of the processing conditions is required to generate higher grade concentrates that are potentially suitable for commercial applications.