Viscosity of multicomponent slags is one of the crucial physicochemical properties for many
industrial processes and technologies. While the viscosity-temperature relationship of completely
molten slags can well be described by an Arrhenian-type law, the compositional dependence of
viscosity is still not fully understood, especially in compositional regions with the lack of
experimental data (eg at the glass-former concentration of 90 molar per cent or higher). In the
present work major compositional relationships of the activation energy of viscous flow have been
revised for numerous binary and ternary slag systems on the basis of experimental data collected
and stored in the viscosity database OxiVis. For example, it has been found that the activation
energy relevant to the polymerisation effect in binary systems of the MO-GFO type, where MO is
the modifier oxide (ie monovalent K2O, Na2O, Li2O and bivalent CaO, MgO, BaO, MnO, PbO etc)
and GFO is the glass-forming oxide (SiO2 or B2O3) is not always proportional to the third power of
XGFO (contrary to the Urbain formalism) and can vary significantly dependent on the slag system.
Also, the activation energy of the charge compensation effect has been revised for ternary systems
of the AO-MO-GFO and AO-MO type, where AO is the amphoteric oxide (Al2O3, Fe2O3 or other). A
simple polynomial model has been proposed on the basis of the carried-out analysis for estimation
of viscosities of multicomponent slag systems. The model has been optimised against the
experimental viscosities in the selected binary, ternary, and higher-order oxide systems and has
been shown reasonable agreement with the experimental data.