Author(s)

Xiaosheng Yang¹, Jukka Laukkanen¹, Akseli Torppa², Neea Heino¹

¹Geological Survey of Finland, GTK Mintec, Outokumpu, Finland.
²Geological Survey of Finland, Kuopio, Finland.

The Lamujärvi syenites intrusions occur within Svecofennian (ca. 1.92 Ga) gneisses, ca. 70 km west of the Otanmaki alkaline area in central Finland. Previous studies have revealed zones in the syenites that display strong enrichment in Zr (1587 ppm), Nb (up to 685 ppm), Ta (up to 82 ppm), and REE (up to 5350 ppm). The major REE-bearing minerals in the Lamujarvi syenites are allanite and monazite. A sample of the Lamujärvi syenites with the REE content of 4700 ppm was studied on the mineralogy and beneficiation at GTK Mintec. The mineralogical analysis was conducted by MLA. The REE-bearing minerals allanite, parisite, zircon, and apatite were identified at significant concentrations and high contents of titanite (15.4%), biotite (30.9%) and magnetite (8.2%) were displayed in the sample. The beneficiation experiments by flotation, wet low and high gradient magnetic separations and gravity separation with a shaking table were carried out. A composite REE-Ti concentrate with REE 23,000 ppm, Zr 5000 ppm, Nb 3400 ppm and TiO2 25.5% at REE and Ti recoveries of 57% and 54% was obtained. In addition, biotite and magnetite concentrates were gained as by-products.

The Lamujärvi Syenites, Mineralogy, Beneficiation, Allanite, Titanite

Yang, X. , Laukkanen, J. , Torppa, A. and Heino, N. (2016) Mineralogy and Beneficiation of Lamujärvi Syenites. Natural Resources, 7, 481-493. doi: 10.4236/nr.2016.78041.