Although several countries have confirmed the presence of Rare Earth Elements (REEs) reserves, China has monopolized the market since the 1990s. Until 2015, the territory of the city of Baotou was responsible for approximately 95% of the world supply of REEs. The United States of America is developing the project called Bear Lodge, which has the potential to compete with China mainly in relation to the production of Nd, Eu, Tb, Dy and Y. However, the North American country indicates that, contrary to the Asian country, production will be carried out with reduced atmospheric emissions.
In the period between 1886 and the second decade of the 20th century, Brazil was the world’s largest exporter of monazite, an ore that contains Rare Earth Elements in the form of phosphates. However, the Brazilian production of REEs became insignificant as time went by. In 2014, imports of chemical compounds and manufactured products from REEs totaled US$ 13 million, while exports totaled only US$ 383 thousand. On the other hand, Brazilian REEs reserves became the second largest in the world recently, with the incorporation of expressive reserves in Minas Gerais and Goiás states.
Part of the REEs produced in Brazil are consumed directly by national industries (catalysts, glass and ceramics), in addition to indirect consumption by manufacturers of wind turbines and engines. For instance, Nd is used as a magnetic material in hybrid cars, wind turbines, and surgical robots. The combination of Y, Pr and Nd can improve the impact resistance of glass and decrease its expansion degree. In general, modern industry makes extensive use of REEs in a wide range of high-added value products.
Development of technologies for processing REE-rich minerals is essential for the use of Brazilian deposits, ensuring that the country positions itself not only as a miner, but as a producer of concentrated REEs, granting independence on the global scenario. The internal production of REEs is considered a matter of public safety, as these elements have been increasingly required by high-tech industries. Enriching REEs internally would make Brazil independent of other countries, reducing imports, increasing exports and generating wealth and foreign exchange for the country.
The problem related to the enrichment of REEs from ores with complex mineralogy such as Kamafugite is the fact that the liquor produced after the various stages of rock dissolution has a diversity of elements and chemical species. And this fact requires the extractor, in solid or liquid form, to be very selective for the separation of groups of REEs or individual REEs. Commonly used enrichment processes involve liquid-liquid extraction, in which a liquid extractor is placed in contact with the liquor containing the REEs. Due to Van der Walls forces and other physicochemical phenomena, REEs diffuse to the extractor, where they are concentrated.
In another approach, REEs are recovered from contact with a solid extractor, in a solid-liquid extraction. REEs adsorb on the surface of the material, and the selectivity for adsorption can be controlled by controlling the physicochemical properties of the surface.
27/2022 CNPq Public Call – Process 407715/2022-3
Coordination: CÃcero N. Ãvila Neto
Contract 38/2022 signed by UFPR and Terra Brasil Participações
Coordination: CÃcero N. Ãvila Neto
