Ferrous sulfate solution Help????????

Question

I made some ferrous sulfate. I placed steel wool into sulfuric acid and waited for it to dissolve. Now I have to evaporate it down to crystals. What is the proper way to evaporate the solution down? What do I put it in and how do I do it so it is safe and effective?

Answer 1

You must make the solution slightly acidic or the ferrous will turn to ferric (red-brown mud) by reaction with the oxygen in the air.  Try 2-3% sulfuric acid and evaporate untill crystals form.  This much acid is not very dangerous, just don't "wear" it.  Glass or plastic containers are OK.