A technique has been developed for the fast measurement of the liquidus
temperature of molten salt systems. The method employs a type K
thermocouple embedded within the centre of a copper cylinder. The
cylinder is immersed into the molten salt bath and the resultant heating
curve is recorded using a PC-based data logging system. Upon
immersion of the cylinder into the bath, a layer of salt freezes from the
melt onto the surface. When this layer remelts during heating, the shape
of the heating curve exhibits a change. The onset of this change can be
detected by numerical differentiation of the heating curve, and the
temperature at the onset represents an estimate of the liquidus of the melt.
This work describes the technique and its application to the measurement
of liquidus temperatures of MgC12 - NaCl and BaC12 - NaCl salt mixtures,
in addition to a number of solidus temperatures.