Production of high-quality ammonium perchlorate crystals using two stirredtanks in series

Ammonium perchlorate crystals with a narrow size distribution and low water content were produced from an apparatus consisting of two batch stirred ta nks in series: one for generating secondary nuclei and the other for growin g crystals. The produced crystals were partially dissolved in a fluidized b ed to obtain rounded product crystals. Operating variables known to influen ce secondary nucleation, crystal growth, and crystal dissolution were inves tigated, including seed weight, seed size, impeller material, agitation spe ed, operating time in the nuclei-generation step, temperature profile in th e growth tank, and undersaturation in the dissolution tank. Finally, the qu ality of crystals produced by the secondary mechanism was compared with tha t produced by the primary mechanism.