Application report: Thermometric titration of sodium, aluminum and fluoride

To obtain a sharp endpoint – and thus reproducible results – with classic titration methods, the reactions on which the titration is based must result in sufficiently large alterations in electrochemical quantities. These changes can be much less pronounced with thermometric titrations, while still yielding exceptionally accurate results – only one of many advantages with this method! A typical example of a thermometric titration is the less well-known exothermic reaction during which the mineral elpasolite (NaK2AlF6) is formed from sodium, potassium, aluminum, and fluoride ions. The industrial determinations of sodium, aluminum, and fluoride are based on this reaction; these are all known as versions of the «elpasolite method».