What is the difference between crystallization and evaporation?

Question

If you want to get a pure solid from a solution, what equipment works the best? Can you get a pure solid out of the evaporator?
Thx

Answer 1

Assuming you are starting with an impure solution (e.g., a mix of two different substances in solution), if you can find a way to grow a small number of large perfect crystals, free of inclusions and dislocations, their purity should be high. The old Inorganic Chem 101 method would be to hang a seed crystal in the solution, remove it every so often and carefully brush it clean, and reinstall it in the solution. (Of course you want to make sure it's the right crystalline form for the substance you want to isolate.) This is time-consuming, and recovering a useful percentage of the total amount in solution would be difficult.
The above applies to inorganics; try googling "purification by crystallization" for any number of references to organics.