in this illustrated embodiment a plurality of pipings for injecting an aqueous phase 6 as droplets each connected to a distributor 7 connected to a supply of aqueous phase 8 as this may be seen in fig1 a or 1b each piping 6 of the plurality of injection pipings is located around the mineral compound injection piping 2 in a space outside the latter called here a peripheral space 9 each aqueous phase injection piping 6 further comprises a valve 10 located between the distributor 7 and the aqueous phase outlet 11 of each aqueous phase injection piping 6 the exit of an aqueous phase 11 as droplets from each aqueous phase injection piping is practically and advantageously achieved by an aqueous phase outlet orifice in the form of a slot of planar spray by means of a nozzle not shown by means of the valves 10 it is possible to not supply some of the pipings 6 and for example only supply those located immediately downstream from the injection point of the mineral compound relatively to the flow direction g of the flue gases in the flue gas conduit 3 the distributor 7 is connected to a pressurized aqueous phase supply 8 in an alternative of the device a pressurizing means 12 gives the possibility of imparting the intended pressure to the water entering via the water supply 8 the pressure of the aqueous phase supply 8 is typically comprised between 2 and 150 bars in one alternative this pressure will rather be comprised between 2 and 20 bars preferably between 3 and 15 bars and still more preferentially of about 8 bars in another alternative.