at present, flue gas desulphurization(De-SOx and de-nitrification(De-NOx) technology applied in sintering machine are NaHCO₃ FGD proecess plus SCR de-NOx process, as well as active carbon De-SOx and active carbon De-NOx. the above two types of processes have been applied in POSCO sinter plant, POSCO applied acitive carbon De-SOx and De-NOx at first, but efficiency is not so good, then POSCO adopt NaHCO₃ FGD proecess plus SCR de-NOx process for sintering machine and achieved satisfied result.