E.N. Selivanov, A.S. Vusikhis, S.V. Sergeeva, R.I. Gulyaeva, V.P. Chentsov, V.V. Ryabov.
ABSTRACT
Boron oxide-based systems are used in the manufacture of glass, glassware, ceramics and various fluxes for refining metals in pyrometallurgical units for ferrous and non-ferrous metallurgy, as well as in the modelling of various metallurgical processes. The results of measurements of the viscosity, density and surface tension of the melts of the B2O3–CaO system are given in the work, with the ratio B2O3/CaO varying between 1.6–3.2, with the additives FeО (up to 67%) in a wide temperature range, as well as the thermal parameters of the solid samples during heating and cooling. Vibration viscosimetry is used to measure the viscosity of the melt, and the density and surface tension of the drop is used to measure the viscosity of the melt. It has been found that the temperature intervals (Tmax–T1) and (T1–T2) corresponding to the high and low temperature homogeneity zones of the melt logarithm of viscosity in the coordinates lnη – 1/T and lnæ – 1/T change linearly at these sites, and the activation energies of the viscous current have been determined. In the temperature range (T2–Tmin) the areas of glazing of the melts B2O3–CaО, as well as crystallization, have been identified, in addition to FeO. The coefficients of equations describing changes in surface tension and density with temperature are determined. The thermal analysis of the samples was performed on the Netzsch STA 449C Jupiter instrument designed for combined thermal and differential scanning calorimetry. The data obtained made it possible to establish the glazing and crystallization temperatures of the melts studied. The data obtained are useful for validation of melt composition for refining metals in pyrometallurgical units.
KEY WORDS:
oxide melt, borate glasses, viscosity, density, surface tension, structure, thermal analysis.
DOI: 10.31857/S0235010621020079