Rheological properties of high-temperature melts of coal ashes and other silicates

This paper reviews the 20th century advances within the field of the measur ement and the prediction of the rheological properties of high-temperature (T > 1000 K) silicate melts at atmospheric pressure with a focus on coal as hes and other melts of compositions relevant to coal ashes. Theoretical considerations are represented firstly by a synopsis of definit ions and how-regimes and secondly by an outline of the ruling network theor y and the notations used therein. The influence of different cations on vis cosity is discussed thoroughly. Experimental points include a listing of the most common apparatus for visc osity measurements on high-temperature liquids and a summary of existing ex perimental data. Viscosity vs temperature is reported in tables as well as graphically for melts composed of major amounts of one or more of the speci es: SiO2, Al2O3, FeOx, CaO, MgO, Na2O, K2O, Li2O, MnO, TiO2, B2O3. For each experimental source, relevant information is listed (apparatus, sensor mat erial, atmosphere). With a basis in both theory and experimental data, general equations for li quids, are presented, relating viscosity to temperature and/or concentratio n of dispersed solids, as are more specific mathematical models, relating t he viscosity of silica melts and glasses to temperature and composition. (C ) 2001 Elsevier Science Ltd. All rights reserved.