The leachings of Si andAl ions of calcined DE and RHA were measured.
The leaching test was carried out by stirring the calcined DE
in 10 Molar (M) NaOH solution with solid to liquid ratio of 1:10
for 24 h. During storage in order not to allow the precipitation of
the dissolved ions prior ion measurement, concentrated nitric acid
was dropped to the samples to obtain pH 4 suspension. The dissolved
Si and Al ions were determined quantitatively using AtomicAbsorption Spectroscopy (AAS).