For what tow purpose are melting points routinely used a. A more common use of recrystallization is in making rock candy. Lightly cover the flask to prevent evaporation and to prevent dust from falling into the solution.
Google Patents: Purification by recrystallization is an important tool for chemical synthesis and analysis. Now that you understand the principles of recrystallization, let's go through a procedure for purification of an organic compound by recrystallization.
Also, it is very important that the proper solvent is used. In these cases, the recrystallization is allowed to proceed very slowly, over the course of weeks to months, to allow the crystal lattice to form without the inclusion of any impurities.