Author(s): Erik Olsson; Per Gren; Henrik Lycksam; Fredrik Forsberg; Mikael Sjodahl
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Keywords: No Keywords
Abstract: Accurate determination of water content in porous materials is essential in many hydro-environmental and industrial systems, where moisture levels influence mechanical stability, energy consumption, and process performance. Conventional laboratory-based measurements are often slow and provide limited real-time feedback, restricting effective monitoring and control. This study presents an optical real-time method for determining moisture content based on dual-wavelength infrared reflectance using lasers at 1310 nm and 1940 nm. The approach exploits the strong absorption peak of water at 1940 nm while using the 1310 nm signal as a reference, enabling robust quantification through the ratio of reflected intensities. The method is demonstrated on iron ore concentrates in a pelletizing process, where moisture control is critical. Tests performed on materials from the Malmberget and Kiruna plants show that the intensity ratio compensates for variations in surface roughness and exhibits a clear linear correlation with the gravimetrically determined moisture content. The results confirm that the dual-wavelength approach provides a stable and reproducible signal suitable for continuous monitoring of water content in granular porous materials.
Year: 2026