Viscosity Measurement of Slags using Rotating Bob and Vibrating Finger Viscometer

Within the present investigation, results of the viscosity measurements using a rotating bob viscometer and a newly-developed vibrating finger viscometer have been presented. The knowledge of the viscosity property of metallurgical slags and fluxes is of major importance considering its tasks of fulfilment in the process of steel manufacturing and casting.Due to the chemical stability of the slag and/or the measurement technology, the measurements were applied in the temperature range from 1300°C to 1600°C. Nowadays, the rotation bob method with a concentric cylinder and a wide gap is the state of the art of the viscosity measuring devices for slags, e.g. rheometers with air bearing. In the present investigation, the Anton Paar MCR 301 rheometer was used as recently reported in Ref. 1). Furthermore, a new vibrating finger viscometer was developed to provide a wider measurement range in high temperature regions from 1 mPa∙s up to 1 Pa∙s dynamic viscosity.2,3,4) In the current investigation, the viscosities of CaO–Al2O3, CaO–SiO2, CaO–SiO2–Al2O3–MgO slags and reference glass have been measured up to 1600°C using the two viscometer apparatuses. The results have been discussed in the context of the high temperature calibration errors, e.g. deviations in geometry of the crucible, the slag stability, the fluid flow, the atmospheric conditions, as well as for the difference in both measurement principles. Also, in the last section of this manuscript, the achieved results have been compared with the previous literature reports.