Rare Eart Elements (REE)

Brazil and the U.S. were once the biggest REE producers

Rare earth elements (REE) are essential part of the green revolution.  Their unique magnetic & heat-resistance properties make them essential in the production of electric motors and wind turbines.  Most of these elements are relatively abundant in the earth's crust, but extraction is complex & costly, as minable concentrations are less common than for most other ores.

  

According to USGS, Brazil ranks third on REE reserves, tied with Russia, with 21,000,000 tons of REO (rare earth oxides) equivalent, after China (44,000,000 tons) and Vietnam (22,000,000 tons).  The U.S. reserves total only 1,800,000 tons, ranking seventh, but its mining production in 2021 was estimated at 43,000 tons, the second largest after China (168,000 tons) [1].

  

According to the Natural Environment Research Council (NERC), more than 200 minerals are known to carry some REE.  However, the minerals that provide REE in economic volume are xenotima, monazite and bastnaesite, the last two being a dominant source of light REE (atomic numbers 57 thru 61) [2].

  

The challenges of REE production include i) lack of technical knowledge for extraction and separation of minerals-ore containing REE, ii) high cost of conventional plants, iii) variable market demand and price, and iv) destination of the generated radioactive waste (tailings which are rich in Thorium and Uranium), requiring complex treatment.

The beginning: Brazil and the U.S.

  

Brazil was the first major supplier of REE, with operations dating back to the 1880s, when it began to exploit monazite sands in Bahia state.  Until 1915, the country was the world's largest REE producer.  From there, Brazil alternated that position with India for 45 years [3].

  

In the 1960s, when it began to be produced commercially, until the 1980s, the main source of REE was the carbonatitic deposit of Mountain Pass, California (still responsible for all U.S. REE current production). China started producing REE at the end of the 1970s, and quickly became the absolute leader worldwide [3], with nearly 90% of the refining capacity.

  

In Brazil, REE are found in the monazite sands of the coast and mainly in deposits close to extinct volcanoes, such as in the cities of Araxá and Poços de Caldas (Minas Gerais state), Catalão (Goiás state), and also in Pitinga (Amazonas state) [3].  Despite having important REE reserves, Brazil’s mine production is among the lowest of all countries, estimated at only 500 tons in 2021 [1].

References

[1] Mineral Commodity Summaries 2022 - Rare-Earths (usgs.gov)

[2] http://recursomineralmg.codemge.com.br/substancias-minerais/terras-raras/

[3] https://jornal.usp.br/ciencias/valiosas-e-versateis-pesquisas-com-terras-raras-mostram-caminho-para-criar-cadeia-produtiva-no-brasil/