Dual-energy computed tomography for improved contrast on a polyphase graphitic ore

Tomography of Materials and Structures, vol. 4, pp. 100021

Abstract

Proper ore characterisation is essential for understanding ore deposits and developing efficient mineral processing flow sheets. Conventional mineralogical and chemical techniques are usually used to study ores, but they can be destructive and, in some cases, provide only 2D information. Computed tomography (CT) is an emerging technology in the raw materials sector enabling the non-destructive 3D analysis of the ore mineralogy and microstructure. However, single-energy CT (SECT) has some limitations concerning the accurate imaging and differentiation of polyphase geomaterials comprising a broad range of attenuation properties. By contrast, dual-energy CT (DECT) uses two different X-ray energies to acquire data, which can be used to distinguish between materials with similar attenuation properties. This study explored the application of DECT for the analysis of a polyphase graphitic ore. A sequential fusion approach was utilized to combine data obtained from different X-ray energy scans at high spatial resolution, and varying weighting factors were applied to determine the optimal contribution of each energy level and spectrum. Both, SECT and DECT datasets were quantitatively evaluated based on the contrast-to-noise-ratio (CNR) and Q factor. The findings demonstrate that DECT significantly improves image contrast compared to SECT while further increases image sharpness. As a result, DECT may enable more accurate segmentation and, therefore, more accurate quantitative 3D analysis of graphite ores.

Authors 4

1. Leonard T. Krebbers corresponding Aachen Institute of Mineral Resources Engineering

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Institute of Mineral Resources Engineering; Wüllnerstraße 2, 52062 Aachen, Germany

   RWTH Aachen University, Institute of Mineral Resources Engineering

   Wüllnerstraße 2, 52062 Aachen, Germany

2. Natalia Grozmani Aachen Laboratory for Machine Tools and Production Engineering (WZL) Chair of Production Metrology and Quality Management Campus Boulevard 27

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Laboratory for Machine Tools and Production Engineering, Chair of Production Metrology and Quality Management; Campus Boulevard 27, 52062 Aachen, Germany

   Campus Boulevard 27, 52062 Aachen, Germany

   RWTH Aachen University, Laboratory for Machine Tools and Production Engineering, Chair of Production Metrology and Quality Management

3. Bernd Georg Lottermoser Aachen Institute of Mineral Resources Engineering

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Institute of Mineral Resources Engineering; Wüllnerstraße 2, 52062 Aachen, Germany

   RWTH Aachen University, Institute of Mineral Resources Engineering

   Wüllnerstraße 2, 52062 Aachen, Germany

4. Robert Heinrich Schmitt Aachen Laboratory for Machine Tools and Production Engineering (WZL) Chair of Production Metrology and Quality Management Campus Boulevard 27

   RWTH Aachen University

   Affiliation as printed

   RWTH Aachen University, Laboratory for Machine Tools and Production Engineering, Chair of Production Metrology and Quality Management; Campus Boulevard 27, 52062 Aachen, Germany

   Campus Boulevard 27, 52062 Aachen, Germany

   RWTH Aachen University, Laboratory for Machine Tools and Production Engineering, Chair of Production Metrology and Quality Management