Here is what I would do...
In the tincture of iodine you have an abundance of KI3 when you react this with an appropriate acid say HCl you are left with KCl and HI3 follow this by the addition of an oxidizer like H2O2 and you will be left with free iodine. Filtration and washing is also required. For best crystals Vapor Deposition is the way to go, but can be quite hazardous to the untrained.
K-I-I-I + HCl ---------> HI3 + KCl
2HI3 + H2O2 -------------> 2I2 + 2H2O