Ammonium phosphate fertiliser solns stabilisation

摘要

Stabilisation of ammonium phosphate fertiliser solns. produced from phosphoric acid obtained by wet decomposition - against precipitation of Mg-salts during storage by seeding with magnesium ammonium phosphate crystals at 37.8-51.7 degrees (pref. not above 40.6 degrees and pH 6.2-7 (pref. 6.2) whilst stirring. The fertiliser solns. are seeded with 2-10% of magnesium ammonium pyrophosphate tetrahydrate crystals which had previously been washed with MeOH/H2O, and passed continuously through a crystallisation vessel whilst stirring and adding crystals over 3 days. Alternatively "ageing" the fertiliser 2-3 weeks prior to treatment reduces the time spent in the crystallisation vessel to 7 hours.