A process for the synthesis of melamine including the purification of the offgas released by the synthesis of melamine by means of a single purification stage (6); in the purification stage (6), the offgas (3) is washed with fresh urea melt and with a recirculated urea melt (8) containing ammonia and melamine precursors (5); said recirculated urea melt is withdrawn from bottom of the single purification stage (6) and cooled in a shell and tube heat exchanger (11), optionally after mixing with the fresh urea melt (15), to a temperature of at least 165 C. preferably in the range 165 C. to 245 C. prior to reintroduction in the purification stage.

A process for the synthesis of melamine including the purification of the offgas released by the synthesis of melamine by means of a single purification stage (6); in the purification stage (6), the offgas (3) is washed with fresh urea melt and with a recirculated urea melt (8) containing ammonia and melamine precursors (5); said recirculated urea melt is withdrawn from bottom of the single purification stage (6) and cooled in a shell and tube heat exchanger (11), optionally after mixing with the fresh urea melt (15), to a temperature of at least 165 C. preferably in the range 165 C. to 245 C. prior to reintroduction in the purification stage.