A carbon core iron ore pellet and a steelmaking method based on a full hydrogen shaft furnace

Abstract

The present invention relates to a carbon-core iron ore pellet, which includes a core layer and a shell layer, wherein the core layer is a mixture of coal powder and a binder; the shell layer is a mixture of iron ore powder and a binder; the core layer is a carbon ball with a diameter of 2-5 mm, and the outer diameter of the shell layer is 8-16 mm. The present invention solves the technical problems that when only hydrogen is used as a reducing agent, the core temperature of traditional iron ore pellets is significantly lower than the surface temperature, resulting in a low reduction rate and difficulty in producing molten steel with a qualified carbon content, as well as the high power consumption, rapid lining erosion, and extended smelting cycle caused by the excessively high DRI melting temperature. Compared with the existing technology, the present invention can effectively supplement the carbon source to the full hydrogen vertical furnace without increasing carbon emissions, and by preparing carbon-core iron ore pellets for smelting in the furnace, it shows better smelting indicators than traditional processes. The present invention also relates to a full hydrogen vertical furnace electric furnace steelmaking method based on carbon-core iron ore pellets.

Description

Technical Field

[0001] The present invention belongs to the technical field of metallurgy, and in particular relates to a carbon-core iron ore pellet and a steelmaking method based on a full-hydrogen shaft furnace. Background Art

[0002] Currently, the steel industry primarily utilizes a carbon-based blast furnace (BF) and converter (BOF) process, encompassing the following key steps: mining / ore dressing, sintering / pelletizing, blast furnace ironmaking, BF steelmaking, continuous billet casting, and hot / cold rolling. BF ironmaking, in particular, relies heavily on fossil fuels (especially coking coal). Consequently, the steel industry is a significant contributor to carbon emissions, with a current carbon intensity of approximately 1.8 tons of CO₂ / ton of steel. To reduce carbon emissions, the steel industry is currently developing innovative all-hydrogen shaft furnace (EAF) processes for a clean energy system. This process uses environmentally friendly hydrogen as the sole reducing agent, converting iron ore pellets into high-metallization direct reduced iron (DRI) in a shaft furnace. The DRI is then smelted and refined in an EAF using electricity, ultimately producing molten steel and slag. Research suggests that, if clean energy is deployed at low cost and scale, the carbon intensity of the all-hydrogen shaft furnace process could be reduced to as low as 50 kg of CO₂ / ton of steel. It must be pointed out that although the success of laboratory experiments and pilot tests have verified the feasibility of the all-hydrogen shaft furnace electric furnace steelmaking process, the following technical problems still need to be solved urgently:

[0003] (1) Since the reduction of iron oxides by hydrogen is generally a strongly endothermic reaction, the core temperature of the iron ore pellets is significantly lower than the surface temperature in the later stage of hydrogen reduction, which seriously affects the reduction rate and makes it difficult to improve the utilization coefficient of the shaft furnace.

[0004] (2) Since carbon-based media such as carbon monoxide and methane are not used, the carbon content in the DRI produced by the vertical furnace is zero, and its melting temperature is too high, resulting in increased power consumption of the electric furnace, increased lining erosion, and extended smelting cycle.

[0005] (3) In order to obtain molten steel with qualified carbon content, carbon-containing materials can be sprayed into the electric furnace molten pool, but the carbon utilization efficiency of this method is relatively low, and the unused carbon will also cause carbon emissions. Summary of the Invention

[0006] (1) Technical issues to be solved

[0007] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a carbon-core iron ore pellet and a steelmaking method based on a full-hydrogen vertical furnace, which solves the technical problems of low reduction rate caused by the core temperature being significantly lower than the surface temperature, difficulty in producing molten steel with a qualified carbon content, and high power consumption, rapid lining erosion, and extended smelting cycle caused by the excessively high DRI melting temperature.

[0008] (2) Technical solution

[0009] In a first aspect, the present invention provides a carbon core iron ore pellet comprising a core layer and a shell layer, wherein the core layer is a mixture of coal powder and a binder; the shell layer is a mixture of iron ore powder and a binder; the core layer is a carbon ball with a diameter of 2-5 mm, and the outer diameter of the shell layer is 8-16 mm.

[0010] According to a preferred embodiment of the present invention, the binder is bentonite, the mass ratio of coal powder to bentonite in the core layer is 100:1-2.5, and the mass ratio of iron ore powder to bentonite in the shell layer is 100:2-3.

[0011] According to a preferred embodiment of the present invention, the content of powder with a particle size of less than 200 mesh in the bentonite is greater than 95%; the pulverized coal is non-coking coal, with a dry basis total sulfur content of <0.5%, and the content of powder with a particle size of less than 200 mesh is greater than 96%; the iron ore powder is hematite powder, with an iron grade TFe of 50-70%, and a particle size of 150-250 mesh, preferably 200 mesh.

[0012] According to a preferred embodiment of the present invention, the carbon core iron ore pellets are prepared based on the cold consolidation method using a disc pelletizer and a pelletizer; the operating pressure of the pelletizer is 10-20 MPa; the compressive strength of the carbon core iron ore pellets is >1500 N / ball, the drop strength is >8 times / ball (test conditions are national standards, free fall from a height of 500 mm onto a steel plate), and the porosity is 16-18%.

[0013] According to a preferred embodiment of the present invention, the carbon core iron ore pellets are prepared as follows: coal powder and bentonite are mixed with water, pelletized in a disc pelletizer, and then sent to a pelletizer to form a core layer under a pressure of 10-20 MPa; iron ore powder and bentonite are mixed with water to obtain a shell material, the shell material is coated on the surface of the core layer in a disc pelletizer, and then sent to a pelletizer again to obtain carbon core pellets under a pressure of 10-20 MPa; the carbon core pellets are sent to a drying kiln and dried at a drying temperature of 180-280°C for 30-60 minutes to obtain carbon core iron ore pellets.

[0014] In a second aspect, the present invention further provides a steelmaking method using a full hydrogen shaft furnace, comprising:

[0015] S1, feeding the carbon core iron ore pellets into a full hydrogen shaft furnace, introducing hydrogen to reduce them, and producing carbon core DRI;

[0016] S2. The carbon core DRI obtained in S1 is mixed with ferrous raw materials and slag forming agent and then fed into an electric furnace. Electricity is applied to smelt the materials in the furnace until the molten steel has qualified components, and then the steel is tapped and cast into billets.

[0017] According to a preferred embodiment of the present invention, in S1, the purity of hydrogen is greater than 95%, the temperature of hydrogen entering the furnace is 900-1100°C, and the hydrogen injection intensity is 1200-1400Nm 3 / tPellets.

[0018] According to a preferred embodiment of the present invention, in S1, the length of the reduction section of the full hydrogen vertical furnace is 4-6 m.

[0019] Preferably, the metallization rate of the carbon core DRI produced by the full hydrogen shaft furnace reduction is greater than 0.96; the reduction stage utilization coefficient is 40-60t iron element / (d·m 3 ).

[0020] According to a preferred embodiment of the present invention, in S2, the ferrite raw material is scrap iron or scrap steel, and the mass ratio of carbon-core DRI to the ferrite raw material is 1-3.

[0021] According to a preferred embodiment of the present invention, in S2, the slag-forming agents are lime and dolomite, wherein the amount of lime added is 40-60 kg / t molten steel, and the amount of dolomite added is 20-30 kg / t molten steel.

[0022] Normally, smelting ends when the carbon content in the molten steel is less than 0.2wt%.

[0023] According to statistics, when steelmaking according to the above method, under normal circumstances, the electric furnace smelting time is <45 minutes, the power consumption is <450kWh / t of molten steel, and the carbon emissions are <0.4t-CO2 / t of molten steel; the total oxygen content of the produced molten steel is <5ppm, and the sulfur content is <10ppm.

[0024] (3) Beneficial effects

[0025] The carbon core temperature within the carbon-core iron ore pellets of this invention is significantly lower than the surface temperature, effectively suppressing the oxidative loss of carbon by iron oxides and preventing carbon emissions. Because hydrogen is not required to reduce the core layer, the average reduction rate of the iron ore pellets within the shaft furnace is significantly increased, significantly improving the shaft furnace's utilization factor. The carbon-core iron ore pellets contain their own carbon, lowering the melting point of the carbon-core DRI produced in the fully hydrogen shaft furnace. This effectively reduces furnace power consumption, slows furnace lining erosion, and shortens the smelting cycle.

[0026] Compared with the method of spraying carbon-containing materials into the furnace bath, due to the high specific gravity of the outer iron shell, the residence time of the carbon core DRI in the furnace bath can be extended, which can effectively improve the utilization rate of the carbon inside it. x O) Rapid reaction and gasification produce local explosions, which can effectively enhance the stirring of the molten pool, uniform the composition and temperature of the molten steel, and help shorten the smelting cycle of the electric furnace.

[0027] The steelmaking method of the full hydrogen shaft furnace of the present invention smelts carbon core DRI and ferrite raw materials together in the electric furnace without the need for oxygen blowing for decarburization, thereby significantly reducing the total oxygen content of the molten steel in the electric furnace. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the structure of the carbon-core iron ore pellet provided by the present invention.

[0029] Figure 2 Schematic diagram of the structure of carbon-core iron ore pellets during the reduction process in a full hydrogen shaft furnace.

[0030] Figure 3 The present invention provides a flow chart of a full hydrogen shaft furnace electric furnace steelmaking method based on carbon core iron ore pellets. DETAILED DESCRIPTION

[0031] In order to better explain the present invention and facilitate understanding, the present invention is described in detail below through specific implementation methods in conjunction with the accompanying drawings.

[0032] like Figure 1 The figure shows a schematic diagram of the structure of the carbon core iron ore pellet of the present invention. The pellet is a core-shell structure, including a core layer 1 and a shell layer 2. The core layer 1 is a mixture of coal powder and a binder; the shell layer 2 is a mixture of iron ore powder and a binder. The core layer 1 is a carbon ball with a diameter of 2-5 mm. If its diameter is too small, it will lead to insufficient carbon supply, and it is necessary to spray carbon-containing materials in the subsequent process to increase carbon; if the diameter is too large, it will cause excess carbon, and it is necessary to blow oxygen for decarburization in the subsequent process to increase the total oxygen content of the molten steel (and the increase in the oxygen content of the molten steel may cause the molten steel to be unqualified). The outer diameter of the shell layer 2 is 8-16 mm. The shell layer 2 is wrapped around the outside of the core layer 1. Among them, the binders used are all bentonite. The mass ratio of coal powder to bentonite in core layer 1 is 100:1-2.5. If the bentonite dosage in core layer 1 is too low, core carbon balls of sufficient strength cannot be obtained, and the core carbon balls are too weak to proceed with subsequent pelletizing. If the bentonite dosage is too high, the carbon content in core layer 1 is too low, which is detrimental to obtaining DRI and molten steel with acceptable carbon content. The mass ratio of iron ore powder to bentonite in shell layer 2 is 100:2-3. Similarly, if the bentonite dosage in shell layer 2 is too low, pellets of sufficient strength cannot be obtained.

[0033] The bentonite used as a binder has a powder content of more than 95% with a particle size of less than 200 mesh (particle size <74 microns). The smaller the bentonite particle size, the larger the specific surface area. Under the same dosage and the same briquetting machine operating pressure conditions, the better the bonding performance of the binder, the greater the compressive strength of the prepared pellets. Preferably, the coal powder used to make the core layer 1 is non-coking coal. Non-coking coal has abundant reserves and low prices, which can reduce the cost of steelmaking raw materials. The total sulfur content on a dry basis is less than 0.5%. Since electric furnace steelmaking cannot be desulfurized, controlling the sulfur content at the raw material end can ensure that the molten steel has a low sulfur content. The powder content of non-coking coal with a particle size of less than 200 mesh (particle size <74 microns) is more than 96%. The finer the particle size, the better the ball-forming property and the higher the strength. Preferably, the iron ore powder used to make the shell layer 2 is hematite powder, with an iron grade TFe of 50-70% and a particle size of 150-250 mesh, preferably 200 mesh. The finer the particle size, the better the ball-forming property and the higher the strength.

[0034] The carbon core iron ore pellets of the present invention are prepared by a cold consolidation method using a disc pelletizer and a pelletizer. The carbon core iron ore pellets can be prepared according to the following method:

[0035] Pulverized coal and bentonite are mixed with water, pelletized in a disc pelletizer, and then fed into a briquetting machine under a pressure of 10-20 MPa to form a core layer 1. Iron ore powder and bentonite are mixed with water to form a shell material, which is coated on the surface of the core layer 1 in the disc pelletizer. The pellets are then fed into a briquetting machine again under a pressure of 10-20 MPa to form carbon core pellets. The carbon core pellets are then fed into a drying kiln and dried at a temperature of 180-280°C for 30-60 minutes to produce carbon core iron ore pellets. This temperature ensures drying while preventing the reaction between the core carbon and the shell iron oxides.

[0036] Based on the carbon core iron ore pellets, the process of the full hydrogen shaft furnace electric furnace steelmaking method provided by the present invention is as follows: Figure 3 As shown in the figure: after the carbon core iron ore pellets are prepared, they are sent to a full hydrogen vertical furnace and reduced by hydrogen to produce carbon core DRI; then the aforementioned carbon core DRI is mixed with ferrous raw materials and slag forming agents and sent to an electric furnace. Electricity is applied to smelt the materials in the furnace until the molten steel composition meets the requirements, and then the steel is tapped and cast into billets.

[0037] When reducing in a full hydrogen vertical furnace, the hydrogen purity is >95%, the hydrogen inlet temperature is 900-1100℃, and the hydrogen injection intensity is 1200-1400Nm 3 / t pellets, the reduction section length of the full hydrogen shaft furnace is 4-6m. The metallization rate of the carbon core DRI produced by the full hydrogen shaft furnace reduction is >0.96, and the reduction section utilization coefficient is 40-60t iron element / (d·m 3 ).

[0038] like Figure 2As shown, this is a schematic diagram of the structure of the carbon core iron ore pellets during the reduction process in a fully hydrogenated vertical furnace. The middle layer is a core layer 1 formed by coal powder, and the shell layer has a gradual change in the valence of the iron element from 0 to 3 according to the different reduction degrees from the outside to the inside of the pellets.

[0039] During electric furnace smelting, the ferrous raw material is scrap iron or scrap steel, and the mass ratio of carbon core DRI to ferrous raw material is 1-3; the slag-forming agents are lime and dolomite, the amount of lime added is 40-60kg / t molten steel, and the amount of dolomite added is 20-30kg / t molten steel. The smelting process is as follows: first, the carbon core DRI is mixed with the ferrous raw material of a certain mass ratio and hot-loaded into the electric arc furnace, and a certain amount of slag-forming agent is added; when entering the arc starting period, the electric arc furnace is powered by low power; after the arc starting period is over, the electric arc furnace is continuously powered by high power until the end of smelting and steel is tapped. The low power is 30-40% of the rated power of the power supply transformer, and the high power is 60-70% of the rated power of the transformer; in the molten pool of the electric arc furnace, the carbon wrapped in the carbon core DRI and the small amount of residual iron oxide (Fe x O) Rapid reaction and gasification, resulting in local explosion, stirring and 0.1-1.0Nm 3 / min / t of molten steel, effectively enhancing molten pool agitation and thus uniforming the steel's composition and temperature. Melting is completed when the carbon content in the molten steel is <0.2wt%. According to statistics, using this method, steelmaking typically results in an electric furnace melting time of <45 minutes, power consumption of <450kWh / t of molten steel, and carbon emissions of <0.4t-CO2 / t of molten steel. The resulting molten steel has a total oxygen content of <5ppm and a sulfur content of <10ppm.

[0040] Example 1

[0041] (1) Preparation of carbon core iron ore pellets:

[0042] Coal powder and bentonite are mixed with water in a mass ratio of 100:1, pelletized in a disc pelletizer, and then sent to a pelletizer to form a core layer 1 under a pressure of 15 MPa. The core layer 1 is a carbon ball with a diameter of 4 mm.

[0043] Hematite concentrate and bentonite were mixed with water in a mass ratio of 100:2 to obtain a shell material, which was coated on the surface of the core layer 1 in a disc pelletizer. The pellets were then sent to a pelletizer again under a pressure of 15 MPa to obtain carbon core pellets. The carbon core pellets were sent to a drying kiln and dried at a drying temperature of 200°C for 40 minutes to obtain carbon core iron ore pellets with a diameter of 12 mm.

[0044] The pulverized coal is non-coking coal, with a particle size of less than 200 mesh accounting for over 96% of the total. The hematite concentrate contains 65% TFe, with a particle size of less than 200 mesh accounting for 60% of the total. Furthermore, the bentonite contains over 95% of the total particle size less than 200 mesh. The resulting carbon-core iron ore pellets have a compressive strength of 1600 N / ball, a drop strength of 10 times / ball, and a porosity of 17.2%.

[0045] (2) Full hydrogen shaft furnace hydrogen reduction:

[0046] The carbon core iron ore pellets are placed in a full hydrogen shaft furnace and reduced with hydrogen to produce carbon core DRI. The reduction section of the full hydrogen shaft furnace is 5m long. The hydrogen purity is 98%, the furnace temperature is 1000℃, and the gas supply intensity is 1300Nm 3 / t pellets. According to calculation, the reduction stage utilization coefficient is 50t-iron element / (d·m 3 After reduction, the metallization ratio of the carbon core DRI was 0.98.

[0047] (3) Electric arc furnace smelting:

[0048] The carbon core DRI and scrap steel were transferred to the electric arc furnace together, with the mass ratio of carbon core DRI to scrap steel being 2. The amount of lime added to the slagging agent was 50 kg / t molten steel, and the amount of dolomite added was 25 kg / t molten steel.

[0049] When the carbon content in the molten steel is less than 0.2wt%, the smelting process is complete and the steel is tapped. Measurements and calculations show that the electric furnace smelting cycle is 43 minutes, the power consumption is 445kWh / ton of molten steel, the carbon emissions are 0.3t-CO2 / ton of molten steel, the total oxygen content in the molten steel is 4ppm, and the sulfur content is 9ppm.

[0050] Example 2

[0051] (1) Preparation of carbon core iron ore pellets:

[0052] Coal powder and bentonite are mixed with water in a mass ratio of 100:2.5, pelletized in a disc pelletizer, and then sent to a pelletizer to form a core layer 1 under a pressure of 10 MPa. The core layer 1 is a carbon ball with a diameter of 5 mm.

[0053] Hematite concentrate and bentonite were mixed with water in a mass ratio of 100:3 to obtain a shell material, which was coated on the surface of the core layer 1 in a disc pelletizer and then sent to a pelletizer again under a pressure of 20 MPa to obtain carbon core pellets; the carbon core pellets were sent to a drying kiln and dried at a drying temperature of 250°C for 30 minutes to obtain carbon core iron ore pellets with a diameter of 14 mm.

[0054] The pulverized coal is non-coking coal, with a particle size of less than 200 mesh accounting for over 96% of the total. The hematite concentrate contains 70% TFe, with a particle size of less than 200 mesh accounting for 70% of the total. Furthermore, the bentonite contains over 95% of the total particle size less than 200 mesh. The resulting carbon-core iron ore pellets have a compressive strength of 1650 N / ball, a drop strength of 11 times / ball, and a porosity of 16.8%.

[0055] (2) Full hydrogen shaft furnace hydrogen reduction:

[0056] The carbon core iron ore pellets are placed in a full hydrogen shaft furnace and reduced with hydrogen to produce carbon core DRI. The reduction section of the full hydrogen shaft furnace is 5m long. The hydrogen purity is 98%, the furnace temperature is 1100℃, and the gas supply intensity is 1200Nm 3 / t pellets. According to calculation, the reduction stage utilization coefficient is 46t-iron element / (d·m 3 After reduction, the metallization ratio of the carbon core DRI was 0.97.

[0057] (3) Electric arc furnace smelting:

[0058] The carbon-core DRI and scrap steel are transferred to an electric arc furnace (EAF) with a mass ratio of 2. The lime addition rate for the slagging agent is 45 kg / t of molten steel, and the dolomite addition rate is 30 kg / t of molten steel. Smelting is completed and tapping is completed when the carbon content in the molten steel is less than 0.2 wt%. Measurements and calculations show that the EAF smelting cycle is 44 minutes, the power consumption per ton of steel is 448 kWh / t of molten steel, the carbon emissions are 0.35 t-CO2 / t of molten steel, the total oxygen content in the molten steel is 4.4 ppm, and the sulfur content is 9.6 ppm.

[0059] Comparative Example 1

[0060] This comparative example is a conventional steelmaking method. The parameters such as hematite concentrate, bentonite, electric arc furnace, full hydrogen shaft furnace, and hydrogen flow conditions used are the same as those in Example 1. However, the pellets produced are iron ore pellets commonly used in the prior art and do not contain a carbon core layer. The steelmaking process is as follows:

[0061] (1) Hematite concentrate and bentonite were mixed with water in a mass ratio of 100:2, pelletized in a disc pelletizer, and fed into a briquetting press to produce iron ore pellets with a diameter of 12 mm under a pressure of 15 MPa. The resulting iron ore pellets had a compressive strength of 1550 N / ball, a drop strength of 10 times / ball, and a porosity of 17.0%.

[0062] (2) The iron ore pellets are placed in a full hydrogen shaft furnace and hydrogen is introduced for reduction to produce carbon core DRI. According to calculations, the utilization coefficient of the full hydrogen shaft furnace reduction section is 40t-iron element / (d·m 3 ), the metallization rate of the carbon core DRI produced by reduction is 0.94.

[0063] (3) After the arcing period, the electric arc furnace is powered at high power until the melt rate of the mixed metal material reaches 80-90%. A carbon-oxygen lance is used to supply oxygen and spray carbon to create foamed slag until the smelting is complete. During smelting, the carbon powder injection rate is 75 kg / min. Measurements and calculations show that the electric furnace smelting cycle is 50 minutes, the power consumption per ton of steel is 465 kWh / ton of molten steel, the carbon emissions are 0.6 tons of CO2 / ton of molten steel, the total oxygen content in the molten steel is 25 ppm, and the sulfur content is 35 ppm.

[0064] The metallurgical indicators such as DRI metallization rate, reduction stage utilization coefficient, smelting cycle, carbon emission, power consumption, molten steel oxygen content, molten steel sulfur content of Example 1, Example 2 and Comparative Example 1 are compared in the following table:

[0065]

[0066] Comparison shows that compared to conventional iron ore pellets, the carbon-core DRI metallization rate obtained by using carbon-core iron ore pellets as the feedstock is increased, the utilization coefficient of the reduction section of the full hydrogen shaft furnace is improved, the electric furnace smelting cycle is shortened, and the power consumption per ton of steel is reduced. In addition, due to the high carbon utilization rate, high stirring intensity of the electric furnace molten pool, and the absence of oxygen blowing for decarburization, the carbon emissions from electric furnace smelting, the total oxygen content and sulfur content in the molten steel are significantly reduced. This shows that compared to the existing technology, the present invention can effectively supplement the carbon source to the full hydrogen shaft furnace without increasing carbon emissions, and by preparing carbon-core iron ore pellets for smelting in the furnace, it exhibits superior smelting indicators compared to traditional processes.

[0067] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A steelmaking method based on a full hydrogen shaft furnace, characterized in that: It includes: S0, preparing carbon core iron ore pellets; The carbon core iron ore pellets include a core layer and a shell layer, wherein the core layer is a mixture of coal powder and a binder; the shell layer is a mixture of iron ore powder and a binder; the core layer is a carbon ball with a diameter of 2-5 mm, and the outer diameter of the shell layer is 8-16 mm; the coal powder is non-coking coal with a dry basis total sulfur content of less than 0.5%, wherein the content of powder with a particle size of less than 200 mesh is greater than 96%; The binder is bentonite, the mass ratio of coal powder to bentonite in the core layer is 100:1-2.5, and the mass ratio of iron ore powder to bentonite in the shell layer is 100:2-3; S1, feeding carbon core iron ore pellets into a full hydrogen shaft furnace, introducing hydrogen to reduce them, and producing carbon core DRI; S2. The carbon core DRI obtained in S1 is mixed with ferrous raw materials and slag forming agent and then fed into an electric furnace. Electricity is applied to smelt the materials in the furnace until the molten steel has qualified components, and then the steel is tapped and cast into billets.

2. The steelmaking method according to claim 1, characterized in that The content of powder with a particle size of less than 200 mesh in the bentonite is greater than 95%; the iron ore powder is hematite powder with an iron grade TFe of 50-70% and a particle size of 150-250 mesh.

3. The steelmaking method according to claim 1, characterized in that The carbon core iron ore pellets are prepared based on a cold consolidation method using a disc pelletizer and a pellet press; the operating pressure of the pellet press is 10-20 MPa; the carbon core iron ore pellets have a compressive strength of >1500 N / ball, a drop strength of >8 times / ball, and a porosity of 16-18%.

4. The steelmaking method according to claim 3, characterized in that The preparation method is as follows: coal powder and bentonite are mixed with water, pelletized in a disc pelletizer, and then sent to a pelletizer to form a core layer under a pressure of 10-20 MPa; iron ore powder and bentonite are mixed with water to obtain a shell material, the shell material is coated on the surface of the core layer in a disc pelletizer, and then sent to a pelletizer again to form carbon core pellets under a pressure of 10-20 MPa; the carbon core pellets are sent to a drying kiln and dried at a drying temperature of 180-280°C for 30-60 minutes to obtain carbon core iron ore pellets.

5. The steelmaking method according to claim 1, characterized in that In S1, the hydrogen purity is >95%, the hydrogen inlet temperature is 900-1100℃, and the hydrogen injection intensity is 1200-1400Nm 3 / tPellets.

6. The steelmaking method according to claim 1, characterized in that In S1, the reduction section of the full hydrogen shaft furnace is 4-6 m long, and the reduction section utilization coefficient is 40-60 t iron element / d·m 3 .

7. The steelmaking method according to claim 1, characterized in that In S2, the ferrite raw material is scrap iron or scrap steel, and the mass ratio of carbon core DRI to the ferrite raw material is 1-3.

8. The steelmaking method according to claim 1, characterized in that In S2, the slag-forming agents are lime and dolomite, wherein the amount of lime added is 40-60 kg / t molten steel, and the amount of dolomite added is 20-30 kg / t molten steel.

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