| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Rare Metal Extraction & Processing
|
| Presentation Title |
Optimizing Zr and REE Recovery from Zircon through a Better Understanding of the Mechanisms Governing its Decomposition in Alkali Media |
| Author(s) |
Yves Thibault, Joanne Gamage McEvoy, Dominique Duguay |
| On-Site Speaker (Planned) |
Yves Thibault |
| Abstract Scope |
Zircon can accommodate HREEs at concentrations where their recovery can be considered. However, one drawback is the aggressive conditions required to break down the zircon structure that typically involves high-temperature treatment (> 500oC) in alkali media. In this context, the study focuses on investigating the mechanisms governing alkali-zircon interaction with the objective of defining optimal Zr/REE recovery pathways. Here we report the progress of alkali fusion experiments coupled with characterization down to the nanometer scale. Our results reveal that zircon is preferentially attacked by specific alkali species infiltrating the crystal structure along a network of defects which are progressively annealed with increasing temperature. Considering that annealing kinetics are faster than the decomposition rate, we will demonstrate that, for certain REE-rich zircons, a process can be designed where > 95% Zr and REE recovery is achieved below 200oC, while treatment at higher temperatures is detrimental, rendering the crystals less reactive. |
| Proceedings Inclusion? |
Planned: |