METHOD OF HEAT TREATMENT OF PELLETS ON ROASTING CONVEYOR MACHINES Russian patent published in 1999 - IPC

FIELD: ferrous metallurgy used in preparation of raw materials for blast-furnace process. SUBSTANCE: method includes step heat treatment in which duration of drying zone treatment amounts to 6%, drying zone by sucking-through, 6-9%; heating zone, 9-12%; roasting zone, 18-21%; recuperation zone, 6%; cooling zone by blowing, 3036%; and zone of cooling by sucking-through, 12-15% of the total time of heat treatment. Heat carrier sucked out of zone of cooling by sucking-through is supplied to zone of cooling by blowing and its temperature is maintained at inlet and outlet of the zone within 70-150 C and 900-1100 C, respectively. Then the carrier is transferred to zones of heating, roasting and recuperation. Temperature of heat carrier in zones of drying by sucking-through, heating and roasting is maintained within the range of 300-350, 500-600 and 1000-1300 C, respectively. Realization of the invention allows rejection of burners in zone of heating and reduction of gas consumption in burners of roasting zone. Simultaneously, due to selection of optimal conditions of heat treatment, destruction in upper overmoistened layers in transition from drying zone by blowing to drying zone by sucking-through is reduced or practically fully excluded. EFFECT: higher efficiency. 2 cl, 1 tbl