BLAST-FURNACE SMELTING METHOD Russian patent published in 2015 - IPC C21B3/00 

FIELD: metallurgy.

SUBSTANCE: invention relates to ferrous metallurgy, namely to a blast-furnace smelting method. The method involves loading to a blast furnace of coke, iron-ore materials, injection to the furnace of heated air saturated with oxygen, additional fuel, and control of composition of cast-iron and slag that periodically leave the furnace. Coke is obtained from coking charge consisting of a mixture of coals and a modifying agent containing 1-5% of sulphur. Amount of the modifying additive is maintained within 3-12%, thus controlling draining capacity of a coke packing in the furnace, which is assessed by DMI index calculated by the following formula: DMI=2·T_c-121·[Si]-128·[P]-156·[S]+11·[Mn]-389·[C]-190·B-690, where T_c - cast iron temperature, °C; [Si], [P], [S], [Mn], [C] - weight content of the above elements in cast iron, wt %; B - basicity of slag (CaO/SiO₂). Value of the index of draining capacity of the coke packing is maintained within 120-250, thus increasing it by increase of a share of the modifying additive in the coking charge. Maximum allowable value of DMI index within the specified limits is determined when sulphur content of 0.025-0.030% is achieved in cast iron.

EFFECT: use of the invention provides regular blast-furnace performance and reduction of coke consumption.

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