Abstract: A method and device is disclosed permitting accurate, reproducible assay of alkali metal and alkaline earth metal contents of molten aluminum over an extended period of use. The sensor of the present invention uses as a reference electrode a calibrated quantity of a sodium-gallium or sodium-indium alloy in the form of a two-phase intermetallic reference system.

Abstract: A thermocouple is disclosed for the continuous measurement of the temperature of a molten phase, which thermocouple comprises two cermet elements of dissimilar metals in which the thermoelectric circuit is closed by the medium, the temperature of which is being measured. The use of dissimilar cermet elements as opposed to conventional metallic wires imparts to the thermocouple sensor a superior resistance to high temperature, corrosive environments which allows it to be used for extended periods of time and for varied applications. A method of using the thermocouple is also disclosed.

Abstract: The continuous monitoring of an element in a molten substance containing same is effected by monitoring the electromotive force generated between a first electrode in contact with the substance and a second electrode in contact with a reference material which is separated from the substance by a solid electrolyte. The reference material comprises a metal and at least one salt selected from the group consisting of (a) a combined salt of the metal and a monovalent metal, (b) a mixture of a first salt of the metal and a second salt of the monovalent metal, the first and second salts having a common anion, (c) a mixture of the first salt and the combined salt, and (d) a mixture of the second salt and the combined salt, the at least one salt being present in the form of a slurry containing a liquid phase in equilibrium with a solid phase, the liquid phase containing the metal and monovalent metal in ionic form and the solid phase containing the first salt, second salt or combined salt.