Process and installation for the production of ammonium nitrate

The invention is carried out in accordance with the following steps: introduction under pressure of a 50-60% nitric acid solution (a) and anhydrous ammonia (b) into a tubular T reactor (3), leading to a solution of ammonium nitrate and to a gas phase; separation of the ammonium nitrate solution from the vapour phase in a discharge chamber (4) of the reactor; subjecting the ammonium nitrate solution to a sudden pressure drop in a further vacuum discharge chamber (7), and immediate passage of the ammonium nitrate solution through a combined evaporator-concentrator (9) adjacent the discharge chamber (7), resulting in separate streams of concentrated ammonium nitrate solution (e) and residual vapour (g). According to the invention, ammonium nitrate solutions of more than 95% concentration are yielded and are suitable for granulation and prilling treatment without a heat supply from outside the system.