Aluminum Determination by Thermometric Titration
An automated technique to determine the aluminum in various samples
This application note describes the thermometric determination of aluminum by titration with sodium fluoride (NaF).
Background
Aluminate, an aluminum solution, is used in many industrial applications as a water softener, as a concrete solidifying agent or in the production of firebrick or zeolite. Furthermore, aluminum hydroxide is present in etching solutions used during aluminum production or electroplating.
The exact content of Aluminum plays an important role in quality control of the products. Thermometric titration allows for an accurate and fast determination of aluminum in acidic, neutral or basic conditions, including etching solutions and aluminate solutions.
Aluminum forms a complex with sodium, potassium and fluoride accompanied by the rise in temperature. In thermometric titration, this change in reaction heat (enthalpy change) is monitored in the course of titration. The titration EQP is recognized and evaluated using a segmented evaluation procedure.
Reaction:
Al3+ + Na+ + 2K+ + 6F- ----------> NaK2AlF6 ↓
Related Applications:
Thermometric Titration of Acid Number according to ASTM D8045
Titer Determination of NaF and Blank Value by Thermometric Titration
