Chemical-looping combustion of synthetic biomass-volatiles with manganese-ore oxygen carriers

•Chemical-looping combustion experiments were performed in a 300 W, CFB reactor for more than 100 h of fuel operation.•Synthesized biomass volatiles, methane and a syngas (CO/H2) were used as fuels.•Five oxygen-carrier materials based on different heat-treated manganese ores were tested.•All manganese ores tested showed some oxygen uncoupling effect.•Fuel conversion was very high for at least three of the materials tested.