Potentiometric measurement of the sodium content of sodium amalgams

Abstract

In the electrolysis cells of a chloro-alkali plant it is important to know the sodium concentration in the flowing amalgams in both the inlet and the outlet of the cell. At present the most commonly used technique for analysing these sodium amalgams is still based on an acid-base titration after reaction of a known amount of amalgam with 0.5 N HCl. This technique is both awkward and time consuming to apply accurately to all the electrolysis cells of a plant. Also, it causes serious environmental problems because of the sampling and treatment of amalgams. A few alternative methods have been suggested¹ but they are not in common use. In this paper we describe an electrode developed to measure the sodium concentration of flowing amalgams in an electrolysis cell. The system is already in routine use in some of our plants.