seen for framstellning of rastal by direktreduktion

摘要

A method for making crude steel has been disclosed where the crude steel is obtained by melt reduction using as raw materials fine grained oxide containing material, fine grained solid, liquid and/or gaseous fuels and oxygen gas; the method comprises the following interrelated steps of feeding the reaction materials into a molten steel bath through at least one compound nozzle, each of which has a central opening and two concentrically surrounding annular slits, injecting said iron oxide containing material, wherein the same may be prereduced to FeO, by admixing said iron oxide material with a fuel including fine grained slag formers, said injecting of the iron oxide, fuel or slag formers being into the steel bath through the inner annular slit at such a depth under the surface of the bath that said iron oxides become melt reduced before these reach the surface of the bath, injecting oxygen, at the same time as said iron oxide containing material, fuel or slag formers are being injected, through the central, circular opening and injecting hydrogen, through the outer annular slit at such a rate that the heat requirement for the melt reduction is satisfied by partial combustion in the bath of hydrogen and carbonaceous material in said fuel and producing reaction gas thereby, utilizing a part of a heat content of said reaction gas and utilizing said reaction gas for said prereduction of the iron oxide containing material, catalytically converting to H2 the reaction gas leaving the steel bath, separating from said catalytically converted H2 gas, CO2 and H2O, said residual gas thus being obtained consisting of hydrogen, which is injected through the inner annular slit of said compound nozzle.