Classifications

• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/52—Manufacture of steel in electric furnaces
  • C21C5/54—Processes yielding slags of special composition
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/52—Manufacture of steel in electric furnaces
  • C21C5/5264—Manufacture of alloyed steels including ferro-alloys
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C5/00—Manufacture of carbon-steel, e.g. plain mild steel, medium carbon steel or cast steel or stainless steel
  • C21C5/52—Manufacture of steel in electric furnaces
  • C21C5/527—Charging of the electric furnace
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/0006—Adding metallic additives
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/0025—Adding carbon material
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
• • C—CHEMISTRY; METALLURGY
  • C21—METALLURGY OF IRON
  • C21C—PROCESSING OF PIG-IRON, e.g. REFINING, MANUFACTURE OF WROUGHT-IRON OR STEEL; TREATMENT IN MOLTEN STATE OF FERROUS ALLOYS
  • C21C7/00—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00
  • C21C7/0056—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires
  • C21C2007/0062—Treating molten ferrous alloys, e.g. steel, not covered by groups C21C1/00 - C21C5/00 using cored wires with introduction of alloying or treating agents under a compacted form different from a wire, e.g. briquette, pellet

Definitions

• the object of the present invention is to further develop this process in such a way that a higher thermal energy can be stored in the pig iron melt.
• a silicon content of at least 0.40 to 5.0 wt.% and a titanium content of at least 0.040 to 0.90 wt.% are set and/or maintained in the pig iron melt during the melting operation and, by means of the converter treatment, a silicon content which is at least 10% lower and a titanium content which is at least 10% lower in the steel melt compared to the pig iron melt is achieved.
• the elements silicon and titanium present in the pig iron melt are preferably in free or dissolved form.
• the aforementioned contents of silicon and titanium in the pig iron melt serve as chemical storage components for energy.
• the pig iron melt can therefore have a silicon content of in particular at least 0.60 wt.%, preferably at least 0.80 wt.%, preferably at least 1.0 wt.%, particularly preferably at least 1.20 wt.%, further preferably at least 1.40 wt.%, and in particular at most 4.50 wt.%, preferably at most 4.0 wt.%, preferably at most 3.50 wt.%, particularly preferably at most 3.0 wt.%.
• the pig iron melt can have a titanium content of in particular at least 0.070 wt.%, preferably at least 0.10 wt.%, preferably at least 0.150 wt.%, particularly preferably at least 0.20 wt.%, further preferably at least 0.250 wt.%, and in particular at most 0.80 wt.%, preferably at most 0.70 wt.%, preferably at most 0.60 wt.%, particularly preferably at most 0.50 wt.%.
• the converter treatment can achieve a silicon content that is at least 10% lower and a titanium content that is at least 10% lower in the steel melt compared to the pig iron melt, whereby the chemical energy can be released in the form of heat through oxidation of the storage components during the further course of the converter treatment and can preferably be used to melt additional iron carriers.
• the silicon content in the steel melt can be reduced compared to the pig iron melt, in particular by at least 15%, 20%, preferably by at least 25%, 30%, more preferably by at least 35%, 40%, particularly preferably by at least 50%, 60%, further preferably by at least 70%, 80%.
• the silicon content in the steel melt can be reduced to at least 0.10 wt.%.
• the titanium content in the steel melt can be reduced by at least 15%, 20%, preferably by at least 25%, 30%, more preferably by at least 35%, 40%, particularly preferably by at least 50%, 60%, further preferably by at least 70%, 80%, in comparison to the pig iron melt.
• the titanium content in the steel melt can be reduced to at least 0.0050 wt.%.
• elements such as Ti in the steel product can significantly influence the production properties.
• additional iron carriers are introduced, which are provided comprising or consisting of sponge iron pieces and/or sponge iron pellets and/or sponge iron briquettes, scrap, blast furnace pig iron, whereby the proportion of the additional iron carriers is at least 3 wt.% and at most 30 wt.% of the total mass of the steel melt produced or to be produced.
• the proportion of additionally introduced iron carriers can in particular be at least 4, 5, 6 wt.%, preferably at least 7, 8, 9 wt.%, preferably at least 10, 11, 12 wt.%, particularly preferably at least 13, 14, 15 wt.% and in particular at most 28 wt.%, preferably at most 25 wt.%.
• oxidation processes take place at high temperatures. Due to the Si and Ti-containing pig iron melt to be conditioned, conventional oxygen blowing produces oxidised solid components, including SiO 2 and TiO 2 , which are transferred into the (converter) slag, as well as gaseous compounds, such as CO and CO 2 , etc.
• the oxidation reaction of Si and Ti each generates an exothermic energy which is higher than the energy required to convert solid iron into a liquid phase, so that the kinetics occurring during converter treatment are suitable for being able to melt additional iron carriers, in particular, without having to incur additional effort and/or costs, and thus to increase the yield or production quantity in relation to the existing amount of pig iron in the converter.
• reduced iron ore carriers in the form of sponge iron pieces and/or sponge iron pellets and/or sponge iron briquettes with a carbon content between 0 and 4.8 wt.%, in particular > 0 wt.%, and a degree of metallization of at least 75% are preferably used as iron carriers (in the smelter).
• the degree of metallization reflects the ratio of the metallic iron content relative to the total iron content in the sponge iron. It can in particular be at least 80%, preferably at least 85%, preferably at least 90%, and ideally up to 100%, in particular up to 99%.
• sponge iron as an iron carrier also brings with it slag-forming components which are naturally present in the iron ore carrier and cannot be expelled in a preceding reduction process, and are referred to as gangue. If the gangue provided via the sponge iron is insufficient, further slag-forming agents can be introduced as additives if required in order to produce a liquid slag which can be further processed. Thus, according to one embodiment, slag-forming agents can be added in order to be able to adjust a basicity B3 in the liquid slag between 0.9 and 1.8.
• B3 can in particular be at least 1.0, preferably at least 1.1 and in particular a maximum of 1.7, preferably a maximum of 1.6.
• the basicity B4 corresponds to the ratio of CaO+MgO to SiO2 + Al2O3 , whereby the determination of the characteristic quantities in the slag in the solid state is within the skill of the art . are familiar. The adjustment of the desired basicity by appropriate mixing/addition is familiar to the expert.
• the slag former comprises at least one or more of the elements from the group (CaO, MgO, SiO 2 , Al 2 O 3 ).
• carbon carriers can be introduced according to one embodiment, in particular in an amount that allows the desired carbon content in the iron melt to be achieved.
• carbon carriers can be introduced according to one embodiment, in particular in an amount that allows the desired carbon content in the iron melt to be achieved.
• all materials in gaseous, liquid and/or solid form with reducible free carbon that can be introduced into the electric smelter are suitable as carbon carriers.
• solid form for example, coke dust, coke slaked coal, coke breeze or coal particles are suitable.
• liquid form for example, ethanol, methanol and other hydrocarbons are suitable.
• carbon-containing gases for example carbon dioxide, methane (natural gas), carbon monoxide, propane and butane are suitable.
• the provided carbon carrier may comprise or consist of coal, biochar, biomass, biogenic and/or non-biogenic plastics.
• SAF submerged arc furnaces
• EAF direct arc furnaces

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Manufacturing & Machinery (AREA)
• Manufacture And Refinement Of Metals (AREA)

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Citations (2)

• 2023
  • 2023-12-18 EP EP23217436.7A patent/EP4575005A1/fr active Pending

Patent Citations (2)

Non-Patent Citations (1)

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