Chemical looping combustion (CLC) technology has attracted a lot of attention given its flexibility to combust nearly all types of fuels with potential 100% carbon capture. This technology utilizes solid oxygen carriers (OCs) to deliver oxygen into the fuel reactor and re-oxidizes OCMs to produce heat for power generation in the air reactor. It is crucial for the technology to obtain an OC that can survive under harsh redox conditions, demonstrate sufficient oxygen transfer capacity and fast kinetics, and be resistant to agglomeration and attrition. Considering the cost, mineral oxygen carriers or waste materials would be promising if they could fulfill the above requirements. In this contribution, we have investigated a series of Fe-based mineral oxygen carriers from Turkey which are either the original hematite ore or wasted sludge from steel factories. To evaluate the thermal effect on the performance of OCs, a thermal treatment was carried out by annealing the OCs at 950°C for 24 h. TGA with an automatic gas mixing system has been used to study the oxygen capacity and reaction rates of OCs, and redox cycle performance. SEM and optical microscopy have been used to check the microstructure change and the stability of OCs under various redox conditions. XRD and XRF have been used to analyze phase structure and element concentration. Reduction kinetics under CO and CH4 has been investigated by a TGA and possible reaction mechanisms have been suggested. Some promising minerals / waste sludges are recommended for the CLC applications.