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Acidified aluminum nitrate solutions were fitrated with alkali (NaOH or KOH) over a temperature range of 24°C to 90°C. A homogeneous distribution of added base was achieved by: (i) in situ decomposition of urea (90°C); and (ii) a novel method involving injection through a capillary submerged in the agitated salt solution.The experimental pH curves are characterized by two plateaus (or platforms) separated by a steep jump in pH. These characteristic features were not previously observed in continuous titration experiments. This is especially true of the second platform, which begins at an OH/A1 ratio larger than 2.5. Stable colloidal solutions or gels are formed on traversing this plateau. The hydrolysis-precipitation behavior was also followed by light scattering and x-ray diffraction measurements.A qualitative picture of the neutralization process is developed.