| 摘要 |
Small crystals are made by mixing a solution of a desired substance with an anti-solvent in a fluidic vortex mixer in which the residence time is less than 1s, for example 10 ms. The liquid within the fluidic vortex mixer ( 12 ) is subjected to high intensity ultrasound from a transducer ( 20, 22 ). The solution very rapidly becomes supersaturated, and the ultrasound can induce a very large number of nuclei for crystal growth. Small crystals, for example less than 5 mum, are formed. The resulting suspension is treated so as to add or remove ingredients, and then spray dried using an atomizer tuned to create small droplets in such a way that each droplet should contain not more than one crystal. Crystal agglomeration is hence prevented. |
