BigPatents India

A carbothermic process of reduction in an externally heated vertical shaft furnace of iron ore to PM grade sponge iron using coke and lime stone as reductant mixture wherein the ore and the reductant mixture are charged from t~e top of the furnace through a co-axial double hopper arrangement having flexibility of changing cross- section with different profiles in an immiscible way thereby avoiding intimate contact between them, the said charge, gravity aided, descending at a constant speed, regulatable, through a preheating zone and subsequently through three reduction zones at optimal temperatures to undergo desired degree of reduction for conversion into PM grade iron powder, encountering no possibility of reverse reaction to be withdrawn along with excess, partially reusable coke through a cooling channel after it has been cooled below the oxidation temperature of the sponge briquette, the withdrawal throughout the shaft being regulated at constant speed, to be discharged out of the axis of the furnace system as handleable pieces using shearing mechanism such that the charge above is not disturbed, the shearing and discharge out of the furnace is hydraulically automated.