Determination of the viscosity of molten KNO3 with an oscillating-cup viscometer

Abstract

An oscillating-cup viscometer for studying high temperature melts was built and absolute measurements on the viscosity of molten KNO₃ along the saturation line have been performed.

For an accurate numerical evaluation of the viscoisty, an assessment on existing rigorous working equations was made.

The temperature range of the present measurements covered up to 973 K where no earlier experimental data are available. In the temperature range where earlier experimental data are available, the measured viscosity of the present study was in good agreement with those of recent studies.

A correlation based on the present results and those of other selected studies was made and the equation is believed to be valid over the whole temperature range where molten KNO₃ is stable. Compared with a current recommendation for the viscosity of KNO₃ proposed by Janz et al., the present equation gives more satisfactory results for the viscosity of molten KNO₃.