Reliable europium thermodynamic database: uses and needs in the energy field

For hydrometallurgy, mining and ore processing, disposal of chemotoxic and radioactive waste as well as for remediation of polluted areas, scientists and engineers from various disciplines need reliable thermodynamic data. Researchers from HZDR, together with colleagues from Sweden and Switzerland, developed a respective database for europium, one of the most important rare earth elements (REE). The result is the first comprehensive, self-consistent, transparent, and openly accessible database of chemical and thermodynamic aspects of that element. Basis is a state-of-the-art critical, internally consistent, and thorough evaluation of all data previously published for europium worldwide. This new compilation of high-quality data will now render extraction, separation, and recycling processes more efficient for europium as well as other rare earth elements. An increased recycling rate of REE, currently lower than 5 %, could decrease the need for exploitation of new primary deposits, reduce environmental impacts, and minimize the overall energy consumption. Further fields of application concern fundamental geological aspects, e.g. relevant for chemical evolutions and alterations of sedimentary rocks and deposits. Eventually, it will also significantly improve mobility predictions of trivalent actinides in nuclear waste disposals where europium serves as a chemical analogue. Thus, the new data will serve both industrial and ecological applications in Germany and many other countries depending on high-technology metals such as europium.