The viscosity of five synthetic silicate melts and one industrial cupola furnace slag were measured by Brookfield (inner cylinder rotation) type viscometer in the temperature range from 1300 to 1500°C.
Chemical composition of the samples was: SiO2 (about 36-51 wt.%), Al2O3 (10-13), CaO (35-48), 8-15 wt.% of MgO, TiO2, FeO and other impurities. These samples were melted in Pt-Rh alloy crucible by electric furnace.
On the other hand, published viscosity data in the literatures were analyzed to obtain SiO2-equivalence of alumina, NA, related to the viscosity of the melts. Hence, NA was formulated as follows: NA=1.68(NAl2O3)0.88(NMO)0.74:nol.fractuin N′A=0.0966(NAl2O3)0.88(NMO)0.74:mol.fraction
Using above equation, the viscosity data in SiO2-CaO, SiO2-Al2O3-CaO and SiO2-Al2O3-CaO-MgO systems could be correlated in a relationship between chemical component index, X=NSiO2+NA, of the melts at the same temperature.
In this paper, a diagram (or Table) of X-temperature-log. viscosity was presented. The availability of this diagram to rough estimation of viscosity in the silicate melts, which were of nearly neutral, ordinary composition was discussed.
The viscosity coeff. obtained in this work and the data from the literature in several multicomponent systems containing small amounts of FeO, BaO, MnO, etc. were in agreement with the diagram, but the viscosity data measured in the graphite crucible and the data in FeO or MnO rich (above 15wt.%) systems indicated poor correspondence to the diagram.