Optimization, Characterization, and Selection of Iron Ores as Oxygen Carriers for Application in Chemical Looping Processes

The industrial viability of chemical looping technology is directly linked to the development of oxygen carriers (OCs) that meet the operational requirements of the process. This study investigates the optimization, characterization, and selection of iron ores from different regions of Brazil as potential OCs for chemical looping applications. A total of 13 samples were analyzed, including 11 predominantly composed of hematite and 2 of ilmenite. These materials were characterized through physicochemical, morphological, and structural analyses using techniques such as X-ray diffraction (XRD), X-ray fluorescence (XRF), temperature-programmed reduction (TPR), and scanning electron microscopy-energy-dispersive spectroscopy (SEM-EDS). The samples exhibited good mechanical strength (≥2.2 N), oxygen transport capacity ranging from 1.21% to 4.90%, and high reactivity during redox cycles with methane and hydrogen. Notably, the FeHP, FeHJ, FeHC, FeLC, FeTiHL, and FeTiHM samples demonstrated outstanding performance in terms of reactivity, cyclic stability, and oxygen transport capacity, showing suitability for operation in the typical temperature range of 800-1100 °C for CL processes. These findings highlight the potential of applying the selected materials in chemical looping technologies, offering sustainable and cost-effective alternatives for CO₂ capture and utilization.