Biomass char conversion is substantially influenced by metals contained in the material. One of the main catalytically active metals in biomass is Fe which occurs in various mineral forms. For an implementation of catalytic effects into char conversion models, investigations on mineral type and loading are required. In this work, the catalytic effect of an Fe loading series on the oxidation of an inherently mineral-free char was analysed. Characterisations focused on the Fe phase present in the char identifying its transition from FeSO4 to Î³-Fe2O3 during doping, and further to Îµ-Fe2O3 and Î±-Fe2O3 upon char oxidation. A very high loading-dependent activity of Îµ-Fe2O3 was found.
Keywords Biomass-derived char, char conversion, Fe minerals, catalytic activity, phase transitions