High-tech metal potential in Finland with emphasis on rare earth elements (REE), titanium and lithium

Abstract

This article evaluates the known rare earth elements (REE), Ti and Li occurrences and exploration potential in Finland, based on existing data combined with new geochemistry and mineralogy, heavy mineral studies, geophysical measurements, geologic mapping and recent drilling of new targets.The potential rock types for REE include carbonatite (Sokli, Korsnäs), alkaline rocks (Otanmäki, Lamujärvi, and Iivaara), rapakivi granite and pegmatite (Kovela), and kaolin-bearing weathering crusts in eastern and northern Finland. The highest REE concentrations occur in late magmatic carbonatite veins in the fenite area of the Sokli carbonatite complex. Detailed mineralogical investigations have revealed three distinct types of REE mineralization as phosphates, carbonates and silicates in the studied areas. Mineralogical and mineral chemical evidence demonstrates that hydrothermal processes are responsible for the REE mineralization in the studied rocks and confirms that such processes are predominant in the formation of REE minerals in carbonatite, calc-silicate rocks and albitite. Titanium occurs as ilmenite in hard rock deposits in Paleoproterozoic subalkaline mafic intrusions. The Otanmäki ilmenite was mined together with vanadium-rich magnetite from 1953 to 1985 from a small gabbro-anorthosite complex, which still contains potential for Ti resources. Other major ilmenite deposits are within the Koivusaarenneva ilmenite gabbro intrusion and Kauhajärvi apatite-ilmenite-magnetite gabbro complex. Possible Ti resources are included in Ti-magnetite gabbro of the large layered mafic intrusions in northern Finland, such as at the former Mustavaara vanadium mine. For several years, Rare Element (RE)-pegmatite of the Kaustinen and Somero-Tammela areas has been the objective of Li exploration by the Geological Survey of Finland (GTK). At Kaustinen, Li-pegmatite occurs as subparallel dyke swarms in an area of 500 km 2 within Paleoproterozoic mica schists and metavolcanic rocks. Li pegmatite contains more than 10% spodumene as megacrysts (1-10 cm), albite, quartz, K-feldspar, muscovite and accessory minerals such as columbite-group minerals, apatite, tourmaline, beryl, Fe-oxide minerals and garnet. The Kaustinen spodumene pegmatite and Somero-Tammela petalite-spodumene pegmatite contain potential Li resources for the battery industry in EU countries.

Lithium in pegmatites of the Fennoscandian Shield and operation prospects for the Kolmozero deposit on the Kola Peninsula (Russia)

“…The most significant of them are the Kaustinen and Somero-Tammela, in particular the Kaustinen, which hosts six largest lithium deposits of Finland. The Kaustinen Li-pegmatite province, covering approximately 500 km 2 is located in western Finland within the Palaeoproterozoic supracrustal rocks of the Pohjanmaa schist belt (1.92 Ga), composed dominantly by the mica schists and gneisses intercalated with metavolcanic rocks (Vaasjoki et al 2005; Sarapää et al 2015; Rasilainen et al 2018). The Pohjanmaa schist belt is bordered by Vaasa granitoid complex in the west and the Central Finland granitoid complex in the east.…”

A Systematic Literature Review on the Titanium Metal Product Value Chain

“…Titanium deposits occur in three industrial groups: coastal-marine and alluvial (stream) placer deposits; primary ore deposits; and the weathering crust of carbonatite complexes [29]. Most of the titanium reserves are confined to primary ore deposits, but placer deposits, also referred to as 'heavy mineral concentrates', are more economically feasible to mine [25,29]. The two most important titanium minerals are ilmenite (FeTiO3) and rutile (TiO2), of which ilmenite is the most common [25].…”

“…Most of the titanium reserves are confined to primary ore deposits, but placer deposits, also referred to as 'heavy mineral concentrates', are more economically feasible to mine [25,29]. The two most important titanium minerals are ilmenite (FeTiO3) and rutile (TiO2), of which ilmenite is the most common [25]. Bykhovskii and Tigunov [29] indicate that the major regions for titanium mining are Australia, Africa (including South Africa), India, China, Kazakhstan, Russia, Ukraine, Canada, and Chile.…”

Flotation of lithium ores to obtain high-grade Li2O concentrates. Are there any mineralogical imitations?

“…At least, 16 separate albite-spodumene-pegmatite occurrences are known in the Kaustinen lithium province [24]. (adapted from [23,28]).…”