METHOD OF PRODUCING AMMONIUM NITRATE AND FILTER ELEMENT FOR FINE PURIFICATION OF GAS-VAPOUR MIXTURE FROM AMMONIUM NITRATE AND AMMONIA BEFORE RELEASE INTO ATMOSPHERE Russian patent published in 2010 - IPC C01C1/18 

FIELD: chemistry.

SUBSTANCE: method involves neutralisation of nitric acid with ammonia gas, evaporation of ammonium nitrate solution to a state of high-concentration melt in an air current, granulation of the melt in a tower, two-step purification of the air mixture in the tower with secondary steam from the neutraliser and gas-vapour mixture from the evaporation apparatus from ammonium nitrate and ammonia impurities, involving washing with a weak ammonium nitrate solution at the first step and fine purification via filtration through material made from superfine fibre at the second step. During filtration, the purified mixture goes through several layers of filter fabric which are distinguished by their characteristics on material, thickness and density. The first layer of filter fabric is constantly or periodically sprayed by a mixture of condensate of secondary and fresh vapour. The spraying condensate which is rich in ammonium nitrate comes out of the filters and directed for feeding the cycle of the washing solution at the fist step of purifying the mixture, for washing the secondary vapour at the outlet of the reactor-neutraliser, after-purification of the gas-vapour mixture from the evaporation apparatus and from after-neutralisation apparatus.

EFFECT: method and filter element enable fine purification of air from ammonium nitrate up to 15-3- mg/m³ and ammonia not more than 5 mg/m³.

4 cl, 2 dwg, 2 ex, 1 tbl