A discharge arrangement (120) for a comminution reactor assembly (100). The discharge arrangement (120) comprises a main chamber (202) extending along a main axis (124). The main chamber has an inlet (121) arranged to be fluidly connected to a comminution reactor (110) and an outlet (122) arranged opposite from the inlet (121) along the main axis (124) and closeable by a common material take-out valve (204). The main chamber (202) is arranged to support a fluid-material stream (123) along a helical path about the main axis (124) from the inlet (121) towards the outlet (122). The discharge arrangement (120) further comprises an airduct (206) arranged extending into the main chamber (202) at an acute angle (a) with respect to the main axis (124). The airduct (206) comprises an aperture arranged facing the outlet (122). Thereby, a portion (125) of the fluid-material stream (123) changes direction from the helical fluid-material stream (123) about the main axis (124) from the inlet (121 ) towards the outlet (122) to a helical flow inside the airduct (206).