Abstract: Improved cooling of sponge iron in the cooling reactor of a multi-stage gaseous reduction system for particulate iron ore is achieved by using a hollow foraminous closure plug at the bottom of the reactor. The plug is pivotally mounted for movement from a reactor-closing to a reactor-discharge position and has a cooling gas inlet nipple which, when the plug is in its reactor-closing position, registers with the discharge end of a cooling gas supply conduit to cause cooling gas to flow into the plug and through the wall thereof to cool the adjacent portion of the sponge iron bed within the reactor. The plug can also be used to distribute hot gas to an ore bed in a reduction reactor.