Sources of REE
World resources are primarily coming from minerals bastnäsite and monazite. Bastnäsite ( China and USA) provides the largest percentage of the world's production. Monazite deposits (Australia, South America, China, India, Malaysia, South Africa, and others) are the second largest. Other important REE-bearing minerals include apatite, cheralite, eudialyte, loparite, phosphorites, REE-bearing clays, spent uranium solutions, and xenotime.
The occurrence of the REE-bearing minerals is connected with variety of igneous, metamorphic and sedimentary rocks. The most significant deposit (Bayan Ono, China) as well as many other occurrences are connected with carbonatites (extrusive or intrusive igneous rocks consisting of more than 50% of carbonate minerals and less than 20% of SiO2) and peralkaline igneous rocks (alkaline igneous rocks having a deficiency of Al and high content of Na and K – syenites, alkaline granites). REE enrichments can also be found associated with hydrothermal veins, breccias and metasomatic zones in a variety of sedimentary and metamorphic environments (placer deposits, laterites, ion-adsorption clays). In general, the world does not lack resources in REE, but the problem is scarcity of economically exploitable deposits with sufficient concentration of REE-bearing minerals.
Two major mining operations outside China are located in USA (Mountain Pass - carbonatite) and Australia (Mount Weld – laterite deposit on carbonatite). At present there is no active mining operation on REE in Europe. Many of the REE were however actually discovered in Scandinavia. Unsurprisingly are reasonably large deposits shown to exist in e.g. Sweden (Norra Kärr – nepheline syenite) and Greenland (Kvanefjeld– nepheline syenite) potentially rivalling the Chinese monopoly. At present, these two deposits are the most advanced towards launching exploitation phase and may secure EU demand for some decades. For more detailed overview of European primary deposits please visit EURARE webpage at www.eurare.eu.
In addition to the primary sources and leaving aside recycling of REE from end-of-life products as other source, tailings and other by-products from previous mining activities may also hold significant amounts of REE. Utilization of such materials may actually help not only to provide additional source of REE but also to environmentally-friendly solution for the mining and processing wastes and to post-mining remediation.
The new mines together with the legacy material may well be enough to provide a reliable, sustainable and sufficient supply for the European industries.
While the primary deposits of REE minerals as mentioned above are handled by other research efforts (e.g. FP7 EURARE project), the ENVIREE project will assist in placing EU among those possessing techniques for a sustainable and resource efficient recovery of REE from sources normally not used in this context.
ENVIREE focuses on the following potential waste materials as sources of REE:
- tailings from lead and zinc ores mining and treatment,
- tailings from copper ores mining and treatment,
- tailings from sulphur ores mining and treatment,
- tailings from processing phosphate ore (phosphogypsum)
- tailings from processing alumina ore (red mud)
- waste rock from other mining of rocks possibly enriched with REE.
For more details about the objectives of ENVIREE, please see section About ENVIREE.