A slag treatment facility according to an embodiment of the present invention comprises a slag treatment apparatus comprising a nozzle part capable of spraying a cooling gas at molten slag, wherein the nozzle part comprises: a first nozzle having, at the lower part thereof, a discharge hole through which molten slag is discharged; and a second nozzle which is mounted on the first nozzle so as to be positioned outside the first nozzle and which comprises a spray channel through which the cooling gas is sprayed in the falling direction of the molten slag to be discharged from the discharge hole. Therefore, the slag treatment facility according to an embodiment of the present invention rapidly cools slag, and thus can inhibit or prevent free calcium oxide (CaO) precipitate generation caused by slow cooling. Thus, when atomized slag is recycled, expansion caused by a hydration reaction can be inhibited or prevented.