If you are going to try 2NH3+H2SO4, then it is not really needed, reaction finishes instantly, if acid is sufficient and reagents are mixed well.
However, if your reagents are concentrated (at least, more concentrated than 10% NH3 and 43% H2SO4, I used), mix could start boiling.
Ammonium sulfate can also be bought as fertilizer (haven't seen though), and of course, chemicals shops have it, in good purity.
If you have a lot of ZnSO4, and don't mind wasting half of Zn, using fertilizer ammonium nitrate (or chloride) is an option. Double Zn-NH4 sulfate is
much less soluble than its constituents. Mix concentrated, hot solutions of ZnSO4 and NH4NO3, and double salt will precipitate:
2ZnSO4 + 2NH4NO3 + 6H2O -> (NH4)2Zn(SO4)2*6H2O ↓ + Zn(NO3)2
(haven't tried exactly this reaction, but it must work)
[Edited on 26-10-2015 by Dmishin] |