Preliminary assessment of the content of rare earth elements, uranium and thorium in tantalite after processing with microwave

Abstract

The microwave application of (MW) was studied with the aim of verifying the potentiality in the processing of tantalite containing compounds of rare earth elements (REEs), uranium and thorium (radioactivity level was below the background). The samples were prepared powdered and had, as initial composition, mainly: Ta2O5 (24.20)%, La2O3 (18.00%), CeO2 (6.30%), Nd2O3 (2.35%), Pr6O11 (1.99%), Y2O3 (1.57%), ThO2(0.11%) and U3O8(0.035%). They were processed in the microwave batch reactor (2.45GHz, 2kW). After the processing, the results of characterization by X-Ray Fluorescence (FRX), Scanning Electron Microscopy (SEM) and Energy-Disperse X-Ray Spectroscopy (EDS) showed that the content of the main compounds of REEs, besides Th and U were: La2O3 (9.38%), CeO2 (20.00%), Nd2O3 (6.29%), Pr6O11 (3.58%), Y2O3 (2.57%), ThO2(0.33%) and U3O8(0.036%). This occurred in the samples prepared with distilled water and irradiated with 15bar of H2. These preliminary tests were promising, but more experiments are needed, since many variables may still be explored and laboratory infrastructure is available for this purpose, at IPEN-CNEN/SP. As the demand for the use of REEs is rapidly increasing, due to the various applications (for example, as neutron moderators in nuclear reactors, special magnets, TV screens, cell phones and computers, catalysts, missiles, electric vehicles, wind and solar energy, among others), future studies would make it possible to add value and improve the quality of this ore. Finally, microwave technology could be used as an alternative for the reuse of these elements contained in mineral exploration residues.