Batch crystallizationoforganiccompoundsfromsolutionisa
widely usedunitoperationintheproductionofpharmaceuticals,
pigments orpolymers.Thereisabigneedtoobtaincertainproduct
specifications duringtheprocess,suchasgoodfilterability,good
flow ability,lowfinesconcentrationandnocakingonstorage.These
specific propertiesmainlydependonthesizeofthecrystalsand
their sizedistributionaswellasthecrystalhabit.
For thesakeoffindinganeffectiveandprecisewaytocontrol
crystallization processesahugenumberofinvestigationswascar-
ried outinthepastdecades.Besidescontrollingthesupersaturation
in termsofthesystemtemperatureoraddingseedcrystalstothe
supercooled solution,theuseofultrasonicirradiationhasbecomean
interesting methodtocontroltheprocessaswellastoinfluencethe
size distributionandthehabitofthecrystallineproduct(Ruecroft
et al.,2005). Seedingandusingultrasoundhaveincommonthat
they leadtoadecayoftheslurryconcentrationatlowerlevelsof
supersaturation andconsequentlycircumventoratleastaffectthe
hardly controllableprimarynucleationathighsupersaturations.