Patent ID: 7976610
Filing Date: 2011-07-12
Classification: C21B,C21C,F27B,F27D,Y02P

Abstract:
1. A direct smelting process for producing molten metal from a metalliferous feed material in a direct smelting vessel, the process comprising: (a) direct smelting metalliferous feed material above atmospheric pressure in a direct smelting vessel containing a molten bath of metal and slag and producing process outputs of molten metal, molten slag, and an off-gas, the process including supplying (i) pretreated solid metalliferous feed material, (ii) solid carbonaceous feed material, and (iii) air or oxygen-enriched air to the vessel; (b) splitting the off-gas released from the direct smelting vessel into at least two off-gas streams including a first off-gas stream and a second off-gas stream, using the first off-gas stream in a pretreatment apparatus for pretreating metalliferous feed material that is subsequently supplied to the direct smelting vessel, and using the second off-gas stream as a fuel gas in at least one of (i) stoves for generating a hot blast of air or oxygen-enriched air and (ii) a waste heat recovery apparatus for generating steam; and (c) controlling pressure in the direct smelting vessel by controlling off-gas pressure in the second off-gas stream while the process is operating in accordance with step (a) and producing molten metal; wherein step (c) includes controlling the pressure in the direct smelting vessel by controlling the flow of off-gas flowing through a pressure control scrubber by opening or closing an off-gas flow control valve in the pressure control scrubber.