IMPROVEMENT OF CRYSTAL REFINING TECHNOLOGIES BY CONTROLLED CRYSTALLIZATION

摘要

A method is provided for making large, uniform and individual crystals fromaqueoussolutions including the steps of obtaining a concentrated aqueous solution bymeans ofevaporation; rapidly cooling the solution from a post-evaporation hightemperature to a firstlower temperature, wherein the first lower temperature is lower than the post-evaporation hightemperature and further wherein the first lower temperature is an isothermalcrystallizationtemperature of said solution; generating a batch of initial nuclei by inducingnucleation at thefirst lower temperature and starting crystal growth; uniformly spreading theinitial nuclei into abulk solution; maintaining simultaneous and rapid growth of crystals from thenuclei at the firstlower temperature for a predetermined length of time; continuing the growth ofthe crystals toproduce large, uniform and individual crystals for a predetermined length oftime at atemperature that varies gradually from between a first lower temperature to asecond lowertemperature, wherein the second lower temperature is a temperature lower thanthe first lowertemperature and further wherein the second lower temperature is an endtemperature ofcrystallization; and recovering the large, uniform and individual crystals.Parameters and asystem for producing lactose monohydrate crystals using the method are alsoprovided.