GB1221791A - Fertilizer compositions - Google Patents

Abstract

1,221,791. Mixtures of ammonium nitrate and ammonium phosphate. FISONS FERTILIZERS Ltd. 4 July, 1968 [25 July, 1967], No. 34002/67. Headings C1A and C1B. Molten mixtures of ammonium nitrate and ammonium phosphate are prepared by reacting, in a first stage, phosphoric and/or nitric acid with gaseous or aqueous ammonia in the presence of nitrate and phosphate ions, the ammonia being in an amount in excess of that which can be absorbed by the reaction mixure; and contacting, in a second stage, the ammonia which is not absorbed in the first stage in further nitric and/or phosphoric acid which is intended for use in the first stage, both stages being carried out at sub-atmospheric pressure, and at the boiling point of the materials of that stage. The pressure may be 25-250 mm. Hg. The ammonium phosphate produced has an N: P ratio of 0.9 : 1 to 1.8 : 1, and the mixture may have an N: P 2 O 5 ratio of 1: 2 to 3 : 1. The amount of water added in the first stage is preferably 10-20% by wt., based on the total weight of materials fed to this stage. The reaction may be between ammonia and phosphoric acid, nitrate ions being added as ammonium nitrate, when the phosphoric acid used may be from 30-55% P 2 O 5 by wt. The molten mixtures may be granulated, prilled or flaked for use as a fertilizer, when potassium salts, e.g. KCl, K 2 SO 4 ; ammonium sulphate, urea or trace elements may be added.