METHOD FOR PRODUCING CAST IRON BY DUPLEX-PROCESS OF ROMELT (VERSIONS) Russian patent published in 2017 - IPC C21B13/14 

FIELD: metallurgy.

SUBSTANCE: invention relates to production of liquid iron from poor iron ores, containing 35-52% of total iron with Fe₂O₃/FeO ratio higher than 1.5 in two bubbling-type furnaces connected to each other by a chute. Iron ore, coal and fluxes are continuously charged into slag bath of the first furnace. The resulting melt with partially reduced iron oxide flows into the second furnace for performing iron reduction and iron production. The gases leaving the slag bath are burnt in the above-slag space with oxygen supplied through tuyeres for afterburning. For implementation of the first version of the invention, the flue gases of the first and second furnaces are removed in separate flue ducts into waste-heat boilers for steam production. For implementation of the second version of the invention, the flue gases after the afterburning in the second furnace are supplied in gas flow to the first furnace, where they are burned in the above-slag space by oxygen supplied to the tuyeres additionally installed for afterburning. After mixing with gases of the first furnace, flue gases are removed into waste-heat boiler for steam production through the flue duct of the first furnace.

EFFECT: increased iron oxide reduction rate, reduced loss of iron with slag by value less than 5 percent when melting highly oxidized materials.

6 cl, 1 tbl, 1 dwg