One of the most crucial problems in using biomass fuel is the amount of solid wastes produced, which will cause serious deposition and corrosion. This work is mainly focused on an evaluation of ash fusion characteristics of eucalyptus bark, lignite and their blends by using thermal analysis technique. The ash deformation temperatures of eucalyptus bark and lignite were 1181 degrees C and 1320 degrees C. The differences between ash softening temperature and hemispherical temperature were 31 degrees C and 13 degrees C for biomass/lignite blends with biomass blending ratios of 20% and 80%. Also, the influences of blending ratio and heating rate on the co-fusion kinetics of eucalyptus bark and lignite were revealed based on two-stage scheme, which referred to pre-peak and post-peak around maximum reaction rate point in the main ash fusion region. The activation energy of ash fusion for eucalyptus bark/lignite blends in the pre-peak stage and the post-peak stage was in the range of 419-828 kJ/mol, and 322-702 kJ/mol, respectively. The biomass blending ratio should be controlled within 40% in order to reduce the possibility of sintering for eucalyptus bark/lignite blends. The ash fusion kinetic characteristics of mixture samples had no linear relation with blend ratios due to interaction between biomass and coal. (C) 2015 Elsevier B.V. All rights reserved.