Advanced X-ray-based 3D structural and chemical characterisation of ores

Understanding the 3D distribution of elements within mineralised rocks is crucial for understanding the formation of mineral deposits and developing efficient extraction methods1,2. X-ray microtomography (micro-CT) has established itself as an important tool to non-destructively characterise a wide-range of materials including ores and building materials over the last years2. However, traditional micro-CT imaging still only provides indirect insight into the chemistry of a material2. To address this challenge, a continuous effort is undertaken at the Ghent University Centre for X-Ray Tomography (UGCT) to develop workflows and bring techniques previously only available at the synchrotron to the lab, where they can be used on a routine basis on a wide-range of samples1,3–5.Here, we show how lab-based hyperspectral CT, a technique based on the difference in X-ray absorption energy of elements present within the sample6, can be used to differentiate between different mineral grains in mineralised samples. The association between specific elements and mineral phases and specific rock textures can then be studied in 3D, giving important insight into the formation process of the different minerals of potential economic interest. By complementing the capabilities of 3D hyperspectral CT and 2D scanning electron microscopy-based energy dispersive spectroscopy (SEM-EDS) a correlative workflow can be created to characterise materials crucial for the energy transition and a circular economy.Understanding the 3D distribution of elements within mineralised rocks is crucial for understanding the formation of mineral deposits and developing efficient extraction methods1,2. X-ray microtomography (micro-CT) has established itself as an important tool to non-destructively characterise a wide-range of materials including ores and building materials over the last years2. However, traditional micro-CT imaging still only provides indirect insight into the chemistry of a material2. To address this challenge, a continuous effort is undertaken at the Ghent University Centre for X-Ray Tomography (UGCT) to develop workflows and bring techniques previously only available at the synchrotron to the lab, where they can be used on a routine basis on a wide-range of samples1,3–5.Here, we show how lab-based hyperspectral CT, a technique based on the difference in X-ray absorption energy of elements present within the sample6, can be used to differentiate between different mineral grains in mineralised samples. The association between specific elements and mineral phases and specific rock textures can then be studied in 3D, giving important insight into the formation process of the different minerals of potential economic interest. By complementing the capabilities of 3D hyperspectral CT and 2D scanning electron microscopy-based energy dispersive spectroscopy (SEM-EDS) a correlative workflow can be created to characterise materials crucial for the energy transition and a circular economy.C