Publication details
Micro-analytical instruments for investigation of elemental and mineral distribution in uranium-bearing sandstones
| Authors | |
|---|---|
| Year of publication | 2017 |
| Type | Conference abstract |
| MU Faculty or unit | |
| Citation | |
| Description | Innovative methods in the investigation of low-grade uranium ores were tested. As the individual ore components in the rock are optically undetectable, we focused on the detection of selected elements (U, Zr, Fe, Nb), their possible associations and distribution. For this purpose, mineral mapping of sample surface was used. The studied samples are uranium-bearing sandstones with remarkable elemental and mineral compositions. Low concentrations of the main ore elements and the small size of mineral phases (in microns) require a sophisticated approach. X-ray fluorescence (XRF) was used to obtain elemental maps. Mineralogical analysis was performed using automated mineralogy systems (TIMA3) that included a FEG-SEM with three EDS detectors. Data from the automated mineralogy systems were verified by X-ray powder diffraction (XRD) analyses. XRF analyses allowed to detect accumulations of the elements of interest across maximum possible surface areas. The resulting elemental maps showed a strong association of U–Zr and a high variability in the distribution of other elements. Furthermore, this micro-analytical technique represents a fast and effective tool for an effective selection of ore material in the preparation of thin sections and other types of samples. The mineral maps were used to establish modal mineralogy and confirm the bulk rock chemical composition. Hydrozircon was identified as the main uranium phase, and the other determined ore minerals included rutile, pyrite and magnetite. Mineral maps show two styles of mineralisation: hydrozircon as cement and hydrozircon in micro-grains dispersed in clay matter. XRD phase analyses verified the mineral composition and match well with the XRF-based elemental maps. The applied micro-analytical instruments and their combination proved to be efficient in the investigation of the given type of samples. |