Catalytic hydrolysis of waste residue from the melamine process and the kinetics of melamine hydrolysis in NaOH solution

The catalytic hydrolysis behavior of waste residue from the melamine process (OAT) and the hydrolysis kinetics of melamine in NaOH aqueous solution were studied in a batch operation autoclave reactor. The results showed that OAT mainly contains melamine, ammeline, ammelide and cyanuric acid. Acid and alkali can both be used as a catalyst to lower the hydrolysis temperature and intensify the hydrolysis process. The optimized operation parameters for the hydrolysis of melamine were: 200 A degrees C, pH 13.26 and a reaction time of 2 h. Melamine was hydrolyzed sequentially to ammeline, ammelide, cyanuric acid and NH3 + CO2. The kinetic results showed that the hydrolysis of melamine, ammeline, ammelide and cyanuric acid all are first order reaction. The kinetic models provide good prediction results of the OAT hydrolysis behavior in NaOH aqueous solution.