Abstract
When aluminum-clad uranium elements of a nuclear reactor are dejacketed with sodium hydroxide, it becomes necessary to determine free alkali (sodium hydroxide that is not combined with aluminum) in the solution.
A pH titrimetric method has been proposed for this purpose. To the sample solution triethanolamine is added to mask aluminum, and the solution is titrated with a standard hydrochloric acid while measuring the pH of the solution at regular intervals. A titration curve (pHml of hydrochloric acid) is then constructed and the end point is determined graphically. Sodium nitrate and sodium nitrite do not interfere with the determination of free alkali.
By the proposed method more than 0.5meq. of free sodium hydroxide in the presence of 5m mol of aluminum can be determined rapidly.
The method will also be useful in the processes of extraction of aluminum from bauxite.
