As one major barrier for biomass combustion, the high -temperature silicate melt -induced slagging is studied by additions of Si02, kaolin, and soil and two types of K2O-SiO2-Al2O3 ternary phase diagrams constructed on basis of the real biomass ash properties and biomass by addition of K2O (in the form of KOH), SiO2, and Al2O3, respectively. Results show that FT can be as the evaluate index for high temperature silicate melt -induced slagging which increases with decreased FT. Meanwhile, a set of qualitative criteria on high -temperature silicate melt -induced slagging are proposed. However, because of the refractory minerals originated from additives directly or alumina-silication reactions indirectly when biomass blended with additives, the quantitative prediction of pure biomass and the biomass added additives should be based on the K2O-SiO2-Al2O3 ternary phase diagrams build by pure biomass ash properties and the biomass added Si/Al/K additives, respectively. Overall, FTs show 'V' shaped distributions with increased SiO2, Al2O3, and K2O in ash, respectively. Unlike SiO2 which exacerbates low temperature silicate melt -induced slagging, soil can substitute for expensive kaolin served as additives during biomass combustion. The whole research provides useful guidelines for biomass selection, improvement, and slagging prevention during combustion. (C) 2016 Elsevier Ltd. All rights reserved.