The present invention relates to an ironmaking feedstock comprising a solid CaFe.sub.3O.sub.5 phase. The ironmaking feedstock may be produced by a process comprising reacting a combination of a calcium source and magnetite at elevated temperature under reducing conditions sufficient to produce the solid CaFe.sub.3O.sub.5 phase. The product may be in the form of agglomerates such as pellets, with a compressive strength such that the product is suitable for transportation.

Provided is a blast furnace operation method that enables lowering of the reducing agent ratio of a blast furnace. The blast furnace operation method includes injecting pulverized coal through tuyeres of a blast furnace. The method includes adjusting coal containing moisture and volatile matter to form adjusted pulverized coal having a specific surface area within a range of 2 m.sup.2/g or more and 1000 m.sup.2/g or less, a lower heating value of 27170 kJ/kg or more, and a volatile matter content within a range of 3 mass % or more and 25 mass % or less. The method further includes injecting, through the tuyeres of the blast furnace, pulverized coal in which the adjusted pulverized coal, in a mixing ratio of 10 mass % or more, is mixed.

The invention concerns a method of operating a sinter plant, where a sinter mix is fired in a sintering machine, the method including crushing fired sinter to below an upper particle size limit; screening the crushed sinter to remove fines and separate at least two sinter size fractions, typically smaller, intermediate and upper size fractions; storing each of the at least two sinter size fractions in a respective, separate storage bin, where
the screened sinter fractions are not mixed again at the sinter plant but are forwarded to the blast furnace plant, where they are stored in respective, separate storage bins, and the screened sinter fractions can be intermediately stored in separate bins at the sinter plant, before being forwarded to the blast furnace.

A process and system having a primary crusher to reduce the fragments according to their granulometry; a magnetic separator to remove metallic fragments bigger than a determined granulometry; a rotary dryer to dry slag; an impact mill to disaggregate and fragment slag particles; a classifier for aero-classification and drag of fine and superfine particles; a cooler for cooling slag by means of heat exchange and removal of the fine and superfine particles that were not collected by the impact mill a vibrating sieve provided with two or more decks with screens of predetermined sizes; low-intensity magnetic separators, with generation of non-magnetic slag fractions free from metallic iron and from iron monoxide, and of magnetic fractions composed by metallic iron and iron monoxide; and low-intensity magnetic separators to reprocess the magnetic fractions with generation of concentrate with high metallic iron contents and a product with high concentration of iron monoxide.

The invention relates to the field of producing iron-ore pellets for blast-furnace smelting. In a first variant, a charge contains iron-ore concentrate and manganese limestone as a binding agent and flux, the ratio of charge components in wt % being as follows: 1.0-5.0 manganese limestone; and the balance iron-ore concentrate. In a second variant, the charge contains iron-ore concentrate, bauxite as a modifying agent, and manganese limestone as a binding agent and flux, the ratio of charge components in wt % being as follows: 1.0-3.5 manganese limestone; 1.2-1.5 modifying additive; and the balance iron-ore concentrate. The invention increases the strength of green and sintered pellets while preserving a high iron content, reduces the softening-melting interval of the pellets in a blast furnace, and simplifies the production of iron-ore pellets.

A method for charging raw materials into a blast furnace is as follows. The blast furnace includes a bell-less charging device that includes a plurality of main hoppers and an auxiliary hopper. The auxiliary hopper has a smaller capacity than the main hoppers. The method includes discharging ore charged in at least one of the plurality of main hoppers, and then sequentially charging the ore from a furnace wall side toward a furnace center side by using a rotating chute. The discharging of low-reactivity ore charged in the auxiliary hopper is started simultaneously with a start of charging of the ore or at a point in time after the start of the charging; and then, the low-reactivity ore is charged together with the ore from the rotating chute. The charging of the low-reactivity ore is stopped at least before a point in time at which charging of 56 mass % of the ore is completed.

A surface profile detection apparatus of a burden in a blast furnace includes a rotating plate mounted immediately above an opening part of the blast furnace and configured to rotate about an opening center of the opening part as a central axis, a rotating means for rotating the rotating plate, and a transmission and reception means for transmitting a detection wave such as a microwave or a millimeter wave in a linear shape along a diametrical direction of the rotating plate and receiving the detection wave. The surface profile detection apparatus performs transmission and reception in a direction orthogonal to a rotating direction of the rotating plate while rotating the rotating plate in synchronization with turning of the shooter so that transmission of the detection wave is not interrupted.

A fine ratio measuring device that measures the fine ratio of fines adhering to the surface of the material in the form of lumps includes: an illumination unit that illuminates the material in the form of lumps; an imaging unit that captures an image of the material in the form of lumps and produces image data; and an arithmetic unit including a computation unit that computes a characteristic quantity of the image data produced by the imaging unit and a conversion unit that converts the characteristic quantity computed by the computation unit to the fine ratio.

A method of manufacturing a steel product into at least two different steelmaking units wherein an expected level of CO2 emissions for the manufacturing of said product in each respective steelmaking unit is calculated.

A method to manufacture a steel product in a steelmaking plant including several different tools, the method including the definition of at least two manufacturing routes using different tools and the calculation of the expected level of CO2 emissions associated to each of this defined manufacturing routes.