Recovery of NH3 and NO-3 from concentrated NH4NO3 solutions was studied. Lead(II) oxide was added to 0.1-2 M NH4NO3 solutions at 373 K to precipitate basic lead(II) nitrates and to recover NH3 simultaneously by steam distillation for 0.25-2 h. The effects of the molar ratio of PbO/NO-3 and steam distillation time on the removal of NO-3 and the recovery of NH3, and on the composition of basic lead(II) nitrate were examined. The removal of NO-3 as Pb(NO3)2 · 5Pb(OH)2 and the recovery of NH3 reached about 100% at a PbO/NO-3 molar ratio of 4 for 1 h. Above 0.5 M NH4NO3, the removal of NO-3 was independent of the initial concentration of NO-3. Since the recovery of NH3 was analogous to the removal of NO-3, effective removal of NH3 was important to precipitate nitrate ion as basic lead(II) nitrates. Under the experimental conditions, basic lead(II) nitrates, 2Pb(NO3)2 · 5Pb(OH)2, Pb(NO3)2 · 3Pb(OH)2 and Pb(NO3)2 · 5Pb(OH)2 were formed in single phase or mixed phase.
|Number of pages||9|
|Publication status||Published - 1997 Jul 1|
ASJC Scopus subject areas
- Industrial and Manufacturing Engineering
- Metals and Alloys
- Materials Chemistry