Determination of Na2O from sodium aluminate NaAlO2

The aim of the work was to find a suitable method and conditions for determining Na2O wt.% from NaAlO2. Problems were encountered while titrating NaAlO2 with hydrochloric acid. The problematic area was the pH range 4–10 where aluminum precipitates as hydroxides. The different species of the aluminate solution were determined using potentiometric and complexometric titrations. The equivalent point of the potentiometric titration was detected using Granʹs plotting method. Precipitation of aluminum hydroxides did not interfere with titrations, because in potentiometric titrations the pH value was over 10 and in complexometric titrations the pH was 4. The results were accurate and determinations were easy to carry out. Sodium was also determined by DCP-AES.