The present invention relates to a use of a two-way spray nozzle (1) with protective gas for manufacturing granular sodium percarbonate, said nozzle comprising a central tube (2) having an outlet for an aqueous hydrogen peroxide solution, an inner jacket tube (3) arranged coaxially around the central tube, and having an outlet for aqueous sodium carbonate solution, an outer jacket tube (4) arranged coaxially around the central tube and inner jacket tube, and having an outlet for a protective gas, a threaded ring slot (5) arranged around the central tube at a distance from the outlet of the central tube, wherein the threads of the ring slot are arranged at an angle α with respect of the direction of the longitudinal axis (12) of the central tube, and in which said protective gas is used at a pressure of less than 0.7 bar. The present invention also relates to a method for manufacturing granular sodium percarbonate.