Prediction of Slag Viscosity

Higman and van der Burgt [29] use the identical diagram changing the abscissa to the more general base-to-acid ratio taking into account the whole composition of the ash. 

This more general interpretation includes alumina and iron, which can both occur as major elements in ash. In fact, the relationships are much more complicated and such diagrams can only provide ideas to find a fluxing agent or a blend coal, which might effectively help to approach unity for the B/A ratio. 

Because the temperature of critical viscosity is, of course, related to the ash fusion behavior, it is suggested to be in the range of the ST up to the HT plus lllK [98,99]. Watt refined these estimations involving the main constituents of the slag on a wt% basis, where the sum of all indicated components yields 

The predicted temperature Scy is in °C and can be only understood as a rough estimation [100,101]. 

The most widely used model to predict the temperature-viscosity curve was established by Urbain et al. [102] for ceramic melts and was later applied to natural mineral compositions. The semiempirical model predicts the viscosity of fiilly liquid slags. 

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