Prodn. of reduced iron ore pellets - in installation for mfg. oxidised pellets, with prevention of infiltration of atmospheric oxygen and for recovering zinc-rich fines

摘要

Appts. for the prodn. of oxidised iron ore pellets is used for producing reduced iron ore pellets. Appts. consists of (a) a feed for raw pellets; (b) a transport grid for the pellets which conveys the pellets successively through a drying chamber; (c) a dehydration chamber and a preheating chamber (d) a number of electrostatic pptn. units or bag filters for collecting material from the drying chamber and (e) a sintering oven connected to the preheating oven. A reducing atmosphere is maintained in the oven and the temp. is pref. maintained at 1150-1280 degrees C. The pellets pass over collection screens and through a series of cooling devices before final collection. The gas from the oven is fed into the preheating oven and thence to the dehydration oven and thence to the predrying oven. The exhaust is passed through the filters before being discharged to atmosphere. A separate discharge device is used for the reduced pellets which directs the pellets under a water jet to cool them. A double slide is used to separate the reduced pellet discharge from the oxidised pellet discharge and, to ensure that no air gains access to the pellets, N is introduced in the chamber between the two slides. In the reducing mode, an additional feature enables gas to be removed from the preheat oven and fed through one set of filters in which zinc rich material is recovered. Process enables a single installation to be used for the prodn. of either oxidised or reduced iron ore pellets.