process for the manufacture of ammonium salts by ammoniering of nitric acida possible svovlsyreholdig mixture of phosphoric acid and nitric acid or ammonium nitrate, or both, or a mixture of nitric acid and sulfuric acid in two steps.

摘要

PICT:1042132/C1/1 The invention comprises a process for making ammonium nitrate or mixtures of ammonium salts containing ammonium nitrate wherein in a first stage a liquid mixture containing ammonium nitrate and nitric acid is formed or an acid mixture containing ammonium nitrate and at least one of ammonium sulphate and ammonium phosphate is formed in the liquid phase, and wherein in a second stage the product from the first stage is treated in the liquid phase at an elevated temperature with a countercurrent stream of ammonia gas, the second stage being operated so that the water vapour evaporated as a result of treating the product from the first stage with ammonia gas is removed out of contact with the mixture being treated with ammonia in the second stage at a point where the pH of the liquid phase is the same as that of the product from the first stage, and if any water vapour is separated in the first stage this is done at a similar pH to that at which water vapour is separated in the second stage. When making ammonium nitrate the pH is preferably in the range of 3.5 to 4.5, and when making mixtures of ammonium salts a pH of 2.0 to 3.0 is preferably used. In the second stage a suitable gas inert to the reaction mixture may be fed along with the countercurrent stream of ammonia. Part of the final product may be returned to the first stage. Example 1 refers to the flow sheet shown in Fig. 1, in which a phosphoric-acid-containing mix is fed from tank 1 through preheater 2 to reactor 3. Ammonia is also fed to reactor 3 through line 5. Water vapour from the boiling partly ammoniated product from reactor 3 is condensed in condenser 10. The ammoniated product is led to the head of reactor 6 while a mixture of ammonia and air is fed to the base of reactor 6 through lines 7 and 8 respectively. Further ammoniation takes place and the resulting product is recovered through line 9. Water vapour and any unreacted ammonia is condensed in condenser 10.