Functionalized mesoporous materials for lanthnides (rare earths) extraction from industrial and mining wastes

点击翻译按钮获取中文摘要

The importance of rare-earth elements (REEs) in the global economy is booming with several modern applications using these elements (electronics, cell phones, flat screen TVs, green technologies, medical devices, military technologies, magnets, solar panels, etc.). Since 95% of the billion dollars market that represents the production of REEs is in the hands of China, a global interest lies in the discovery of new producers to secure this strategic market. A very interesting source of REEs is bauxite residues (BR). The bauxite residues are the most important waste generated by the Bayer process, which is a crucial step in the production of aluminium. Produced at the scale of 900 000 tons annually (for Canada only), the BR are an environmental concern and the aluminum producers are looking for ways to reduce and valorize this important by-product. It is known however that each ton of BR could contains up to one kg of REEs, which according to the current market price represents a market close to one billion dollars. In partnership with Rio-Tinto Alcan and Hydro-Québec, the PIs of this proposal aim at the development of novel materials that can selectively extract REEs from several matrices, including BR, nuclear and electronic wastes and REE mineral and mining residues. The objectives include: a) the development of novel organic molecules that would show selectivity in the binding affinities of REEs, b) the grafting of these organic molecules on silica and carbon supports, and c) the use of these novel materials in the liquid-solid extraction of BR for the separation and purification of REEs. In addition to the economic advantage of such technology, it would also minimize the environmental impact of BRs, and would make the current extraction process of REEs greener, since the technology used is energy and chemically very demanding and is in one of the most polluting mining process.