NOx removal from gaseous effluents

A process for the reduction of mono-nitrogen oxides (NOx) from a gaseous effluent generated in the production of fertilizer comprising the acid digestion of phosphate ore in the presence of urea, wherein said gaseous effluent generated has a NOx composition of 70 to 100 mole % NO2 and 0 to 30 mole % NO, comprising the steps of:

• a) contacting said gaseous effluent for 0.5 to 15 seconds with ozone, thereby providing a resultant gas mixture wherein NO and NO2 present in the NOx are oxidized to higher nitrogen oxides;
• and;
• b) removing higher nitrogen oxides from said resultant gas mixture;
• wherein urea is added during said acid digestion of phosphate ore in an amount between 0.005 wt % and 0.07 wt % based on the weight of said phosphate ore;
• and;
• ozone is added to said gaseous effluent in an ozone/NOx ratio ranging between 0.5 and 1.4, and wherein the resultant gas mixture has a NOx level of less than 90 ppm and an N2O level of less than 15 ppm.