Reduction and melt separation integrated ultra-low carbon ironmaking method

Abstract

The invention discloses a reduction and melt separation integrated ultra-low carbon ironmaking method, which comprises the following steps of: adding iron ore and coke into an ironmaking furnace from a feeding hole, stacking the iron ore and the coke in the ironmaking furnace, and pre-paving a coke bed at a hearth and a bosh as a dead stock column area; hydrogen is conveyed into the ironmaking furnace from the tuyere, and gradient heating is carried out on a reduction zone, a soft melting zone and a dead stock column zone in the furnace; hydrogen enters the furnace and then reacts with the iron ore in the reduction area, and iron oxide is reduced into metal iron; the reduced metallized furnace burden descends to a soft melting zone, is melted in the soft melting zone and drips to a dead stock column area, in the dead stock column area, slag iron penetrates through a coke bed to be subjected to carburizing reaction, then drips to a hearth to achieve slag iron separation, and finally is discharged from a slag iron outlet; and gas and water vapor generated in the furnace are discharged from a furnace top gas outlet, are subjected to water removal, dust removal and CO2 removal, and are circularly input into the furnace again through the tuyere. The ultra-low carbon consumption and emission are achieved to the maximum extent, and extra carburizing treatment is not needed.

Description

Technical Field

[0001] The invention belongs to the technical field of low-carbon metallurgical production, and specifically relates to an ultra-low-carbon ironmaking method integrating reduction and smelting. Background Art

[0002] The steel industry is a major energy consumer, among which the energy consumption and emissions of the blast furnace ironmaking system account for more than 70% of the total energy consumption and total emissions of the entire steel process. Therefore, the ironmaking process must promote efficient ultra-low carbon smelting technology. Hydrogen metallurgy is a technology that uses hydrogen energy to replace traditional fossil energy for reduction. It is crucial to promote the green and sustainable development of the steel industry and is the main means to promote the peak carbon emissions of the steel industry and deep emission reduction. At present, the main application directions of hydrogen metallurgical technology and processes are blast furnace hydrogen-enriched smelting process and non-blast furnace hydrogen-based reduction process. Blast furnace hydrogen-enriched smelting technology is based on traditional blast furnaces. By injecting hydrogen to partially replace coke and pulverized coal, carbon emissions are significantly reduced. Coke not only provides the necessary reducing agent in the blast furnace, but also plays a role in supporting the charge structure, maintaining the airflow distribution in the furnace and providing heat. However, the significant disadvantage of the blast furnace hydrogen-enriched process is that it still relies on coke and pulverized coal as the main reducing agent. This is because the competitive reduction reaction between carbon and hydrogen in the furnace (i.e., water-gas reaction) leads to low hydrogen utilization, and there is still a large amount of carbon-oxygen combustion reaction in the tuyere, which ultimately leads to limited carbon reduction capacity of the process. The non-blast furnace hydrogen-based shaft furnace reduction process uses hydrogen as a reducing agent, and its reaction process produces almost no carbon dioxide. However, this process has three significant disadvantages: ① The reduction product is a solid metallized pellet, which needs to be cooled for subsequent processing, and there is a large amount of heat loss in this process; ② When the metallized pellet is cooled to room temperature, the high chemical potential contained in it makes it a potential source of spontaneous combustion. In order to reduce the risk of spontaneous combustion, the industry often takes measures such as spraying fireproof materials such as cement or paint on the surface of the pellet to form a protective layer to inhibit the occurrence of spontaneous combustion reactions; ③ At the same time, the metallized pellet contains almost no carbon. According to the Fe-C phase diagram, the melting point of the heated melting is high, requiring additional heating and carburizing treatment.

[0003] Patent CN118531178A discloses a low-carbon ironmaking process in an electric vertical furnace. Iron ore enters the furnace from the feed port, is preheated by the gas rising from the reduction section in the preheating section, and then enters the reduction section to undergo a reduction reaction with the gas rising from the heating section, reducing the iron oxide in the iron ore to metallic iron. After continuing downward through the gas heating section, it enters the melting section for slag-iron separation to obtain slag and molten iron. However, in this process, the reduced metallic iron must first enter the cooling section before entering the melting section to exchange heat with the reducing gas. Although this process utilizes the heat of the metallic iron, it needs to be reheated in the melting section later. Patent CN117778652A efficiently treats and recycles the top gas to achieve zero discharge of the top gas. The specific operation is as follows: after the top gas is dusted, dehydrated, and carbon dioxide removed, a portion of the gas is heated with hydrogen and then introduced from the middle of the melting furnace to provide sufficient air volume and heat for the reduction of the upper iron oxides; the other portion of the gas is heated by plasma and introduced from the bottom to provide heat for the direct reduction and soft melting dripping of the lower part. However, this patent is essentially not much different from the hydrogen-rich blast furnace process. It still uses coke combustion to produce a large amount of high-temperature carbon monoxide to make the iron-containing material soft-melt and drip. The amount of coke used is 233-270kg / t, and it is highly dependent on solid fuels. Therefore, it is necessary to develop an ironmaking method that can achieve carbon reduction without the need for additional carburizing treatment. Summary of the invention

[0004] The purpose of the present invention is to address the shortcomings of the prior art and provide an ultra-low carbon ironmaking method that integrates reduction and smelting. This method can significantly reduce the usage of coke and pulverized coal, maximize ultra-low carbon consumption and emissions, and on this basis does not require additional carburizing treatment, thus solving the problem of limited carbon reduction effect of ordinary blast furnace hydrogen-enriched processes.

[0005] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0006] An ultra-low carbon ironmaking method integrating reduction, smelting and separation comprises the following steps:

[0007] Step 1: Add iron ore and coke into the ironmaking furnace from the feed port and pile them up inside, and pre-lay a coke bed in the furnace hearth and belly as a dead material column area;

[0008] Step 2: hydrogen is transported into the ironmaking furnace from the tuyere, and gradient heating is performed on the reduction zone, soft melting zone and dead material column zone in the furnace;

[0009] Step 3: After hydrogen enters the furnace, it reacts with iron ore in the reduction zone, and iron oxides are reduced to metallic iron; the reduced metallized charge descends to the soft melting zone, where it is melted and drips to the dead material column area, where the molten slag iron passes through the coke bed to undergo carburization reaction, then drips to the furnace to achieve slag iron separation, and is finally discharged from the slag iron outlet;

[0010] Step 4: The gas and water vapor generated in the furnace are discharged from the gas outlet on the furnace top, and after being dehydrated, dusted and CO2 removed, they are circulated through the tuyere and re-introduced into the furnace.

[0011] Furthermore, in step 1, the mass ratio of iron ore to coke added into the ironmaking furnace from the feed port is 12-32:1, and the amount of coke used is 50-150 kg / t.

[0012] Furthermore, the iron ore and coke are added into the ironmaking furnace from the feed inlet in a layered or mixed manner.

[0013] Furthermore, the tuyere of the ironmaking furnace includes furnace body tuyere, furnace waist upper tuyere, furnace waist lower tuyere and furnace hearth tuyere, wherein the number of each type of tuyere is 4-48.

[0014] Furthermore, the furnace tuyere is divided into a working tuyere and a standby tuyere. When the working tuyere of the furnace is unobstructed, hydrogen is transported into the furnace from all the tuyere of the ironmaking furnace.

[0015] Furthermore, when the working air outlet is blocked, the spare air outlet is activated as the working air outlet and hydrogen is sprayed inwardly, and the blocked air outlet is drilled and unblocked, and then used as a spare air outlet after unblocking, or the blocked air outlet is intermittently sprayed with oxygen-enriched hot air for chemical combustion unblocking, and then used as a spare air outlet after unblocking.

[0016] Furthermore, when hydrogen is sprayed, the temperature of hydrogen sprayed from the furnace body tuyere is 150-600°C, the temperature of hydrogen sprayed from the upper and lower tuyere of the furnace waist is 600-1200°C, and the temperature of hydrogen sprayed from the furnace hearth tuyere is 30-1500°C.

[0017] Furthermore, when gradient heating is performed in step 2, the heating power is gradually increased from top to bottom, so that the temperature of the indirect reduction zone is 200-1200°C, the temperature of the soft melting zone is 1200°C-1550°C, and the temperature of the dead material column zone is 1550°C-2000°C.

[0018] Furthermore, after the slag iron passes through the coke bed to undergo carburizing reaction in step 3, the mass fraction of iron in the molten iron is 94-96%, and the mass fraction of carbon is 3-6%.

[0019] Furthermore, in step 4, the gas exhausted from the furnace is treated and then sprayed into the furnace from one or more of the four types of tuyere.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] (1) The present invention achieves ultra-low carbon consumption per ton of iron by presetting the coke bed and distributing the material at an ultra-large ore-coke ratio. The present invention only presets a certain coke bed height when the furnace is opened. The consumption of the coke bed in the subsequent smelting process depends only on the carburizing reaction. The carbon content of the carburizing reaction is only 3-6%, and the required carbon amount is relatively low, thereby greatly reducing the carbon consumption. This is essentially different from blast furnace ironmaking;

[0022] (2) In the actual smelting process, the present invention uses hydrogen sprayed from the tuyere as the main reducing agent. Specifically, full hydrogen spraying is combined with external electric heating to achieve an ultra-high indirect reduction degree, breaking the hydrogen utilization limit of hydrogen-rich blast furnaces. Coke only needs to meet the basic needs of carburizing, which is also impossible to achieve in blast furnace ironmaking. Ultra-low carbon emissions are achieved to the greatest extent, solving the defect of limited carbon reduction effect of ordinary blast furnace hydrogen-rich processes.

[0023] (3) The present invention utilizes the furnace gradient heating technology to make the iron ore soft-melt and drip after reduction, thereby realizing efficient reduction, melting and separation integrated ultra-low carbon ironmaking. Compared with the metallized pellets produced by the non-blast furnace hydrogen-based vertical furnace, the present process directly produces qualified molten iron, which undergoes carburization reaction after passing through the coke bed, thereby avoiding the repeated treatment of first cooling and then heating to melt the metallized pellets. In addition, compared with the traditional non-blast furnace hydrogen-based vertical furnace reduction process, the additional carburization step is omitted;

[0024] (4) The present invention designs multiple types of tuyere and clears the furnace tuyere by physical methods and intermittent chemical combustion. The furnace tuyere hardly burns and consumes carbon, while the traditional blast furnace tuyere has continuous and intense carbon-oxygen combustion. Therefore, carbon consumption and emissions are greatly reduced, and full hydrogen smelting and ultra-low carbon emissions can be achieved, which cannot be achieved in blast furnaces. In addition, the integrated reduction and smelting ironmaking reactor involved in the present invention can be redesigned or appropriately modified on the basis of the existing blast furnace. The modified blast furnace can be called an "electric blast furnace". Compared with newly built non-blast furnace process equipment, the "electric blast furnace" can greatly reduce the investment cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a flow chart of an ultra-low carbon ironmaking method integrating reduction, smelting and separation according to an embodiment of the present invention;

[0026] Figure 2 Schematic diagram of hydrogen injection in the integrated reduction and smelting furnace used in an embodiment of the present invention. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present invention will be described clearly and completely below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0029] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

[0030] The embodiment of the present invention provides an ultra-low carbon ironmaking method with integrated reduction and melting, wherein a certain ratio of iron ore and coke are added to an integrated reduction and melting furnace, the added raw materials form a material column skeleton on the upper part of the furnace body, and a coke bed is pre-laid at the furnace hearth and the furnace belly as a dead material column area; then hydrogen is sprayed into the furnace from the tuyere, and the reduction zone, soft melting zone and dead material column area in the furnace are subjected to gradient heating; after the hydrogen enters the furnace, it reacts with the iron ore in the reduction zone, and the iron oxide is reduced to metallic iron; the reduced metallized charge descends to the soft melting zone, is melted in the soft melting zone and drips to the dead material column area, in which the molten slag iron passes through the coke bed to undergo carburization reaction, and then drips to the furnace hearth to achieve slag iron separation, and is finally discharged from the slag iron outlet; and the gas and water vapor generated in the furnace are discharged from the furnace top gas outlet, and after dehydration, dust removal and CO2 removal, they are circulated through the tuyere and re-introduced into the furnace. The integrated reduction and melting furnace used in each embodiment of the present invention is obtained by transforming an existing blast furnace.

[0031] Example 1

[0032] The raw material and fuel conditions used in Example 1 are derived from actual data of a certain ironmaking plant, with the production of 1 t of molten iron as the calculation base unit. The chemical composition of the ore is shown in Table 1, and the coke composition is shown in Table 2, wherein the proportions of sintered ore, pelletized ore, and lump ore entering the furnace are 71%, 23%, and 6%, respectively.

[0033] Table 1 Chemical composition of raw materials (mass fraction)

[0034]

[0035] Table 2 Chemical composition of coke (mass fraction)

[0036]

[0037] This embodiment provides an ultra-low carbon ironmaking method integrating reduction and smelting, the process flow is as follows: Figure 1 and 2 As shown, the following steps are included:

[0038] Step 1: After the iron ore and coke are evenly mixed, they are added into the reduction smelting integrated furnace from the feed port 1. The ore input amount is 1633.52 kg / t, and the coke input amount is 56.13 kg / t. At this time, the ore-coke ratio is 29. After the raw materials are fully put in, a material column skeleton is formed on the upper part of the furnace body, and then a coke bed is pre-laid in the furnace hearth and the furnace belly as a dead material column area;

[0039] Step 2: 147.77m2 of gas is transported into the furnace from the furnace body tuyere 2 (12), the furnace waist upper tuyere 3 (12), and the furnace waist lower tuyere 4 (24). 3 / t hydrogen, transported from furnace working tuyere 5 (24) to the furnace, 681.10m 3 / t hydrogen, the total amount of hydrogen entering the furnace is 1124.41m 3 / t, among which, the temperature of hydrogen sprayed from the furnace body tuyere 2 is 400°C, the temperature of hydrogen sprayed from the upper tuyere 3 of the furnace waist is 600°C, the temperature of hydrogen sprayed from the lower tuyere 4 of the furnace waist is 800°C, and the temperature of hydrogen sprayed from the working tuyere 5 of the furnace cylinder is 30°C. The reduction and melting integrated furnace is heated by electromagnetic induction, and the heating power is gradually increased from top to bottom. After heating, the temperature of the indirect reduction zone is 200-1200°C, the temperature of the soft melting zone is 1200-1550°C, and the temperature of the dead material column zone is 1550-2000°C. In the entire reduction and melting integrated furnace, as the heating power gradually increases, the temperature in the furnace gradually increases from top to bottom, and the temperature presents a gradient distribution along the height direction of the furnace body;

[0040] Step 3: The iron oxides in the ore are reduced to metallic iron by high-temperature hydrogen in the indirect reduction zone, and continue to descend to the soft melting zone. In the soft melting zone, as the temperature rises, the reduced slag iron is melted and drips into the dead material column area. After entering the dead material column area, the melted slag iron passes through the coke bed to undergo a very small amount of direct reduction reaction and carburization reaction, and then drips into the furnace to achieve slag iron separation, and is finally discharged from the slag iron outlet 6. The molten iron output is 1 t, and the molten iron composition is shown in Table 3. The slag output is 215.14 kg / t;

[0041] Table 3 Chemical composition of molten iron (mass fraction)

[0042]

[0043] Step 4: The gas and water vapor generated in the furnace are discharged from the furnace top gas outlet 7, including: 505.80m 3 / t water vapor, 608.90m 3 / t Hydrogen, 89.60m 3 / tCarbon monoxide, 1.05m 3 / t carbon dioxide is introduced into the furnace from the lower tuyere of the furnace waist and the working tuyere of the furnace hearth after water removal, dust removal and CO2 removal.

[0044] Example 2

[0045] The raw material conditions used in Examples 2-4 are derived from actual data of a certain mining area, with the production of 1 t of molten iron as the calculation base unit, and the ore entering the furnace is pelletized ore, and the chemical composition is shown in Table 4.

[0046] Table 4 Chemical composition of raw materials (mass fraction)

[0047]

[0048] This embodiment provides an ultra-low carbon ironmaking method integrating reduction, smelting and separation, comprising the following steps:

[0049] Step 1: After the iron ore and coke are evenly mixed, they are added into the reduction smelting integrated furnace from the feed port. The ore input amount is 1633.52kg / t, and the coke input amount is 68.13kg / t. At this time, the ore-coke ratio is 24. After the raw materials are fully put in, a material column skeleton is formed on the upper part of the furnace body, and then a coke bed is pre-laid in the furnace hearth and furnace belly as a dead material column area;

[0050] Step 2: 156.01m2 of air is transported into the furnace from the furnace body tuyere (12), the furnace waist upper tuyere (12), and the furnace waist lower tuyere (12). 3 / t hydrogen. As the furnace tuyere is easily blocked by the charge, the furnace tuyere is divided into working tuyere (18) and standby tuyere (12). When the working tuyere is blocked, oxygen-enriched hot air of 67.23m3 is intermittently sprayed to the blocked tuyere. 3 / t to clear the blocked tuyere by chemical combustion, and then use it as a spare tuyere after clearing. The oxygen content of the hot air is 28.47%. At the same time, the spare tuyere is used as the working tuyere and hydrogen is sprayed into it. The amount of hydrogen transported from the working tuyere (18 tuyere) to the furnace is 621.57m 3 / t, the total amount of hydrogen entering the furnace is 1089.60m 3 / t; the temperature of hydrogen sprayed from the furnace body tuyere is 600℃, the temperature of hydrogen sprayed from the upper tuyere of the furnace waist is 600℃, the temperature of hydrogen sprayed from the lower tuyere of the furnace waist is 1000℃, and the temperature of hydrogen sprayed from the working tuyere of the furnace cylinder is 1000℃. The integrated reduction and smelting furnace is heated by electromagnetic induction, and the heating power is gradually increased from top to bottom. After heating, the temperature of the indirect reduction zone is 200-1200℃, the temperature of the soft melting zone is 1200-1550℃, and the temperature of the dead material column zone is 1550-2000℃. In the entire integrated reduction and smelting furnace, as the heating power gradually increases, the temperature in the furnace gradually increases from top to bottom, and the temperature presents a gradient distribution along the height direction of the furnace body;

[0051] Step 3: The iron oxides in the ore are reduced to metallic iron by high-temperature hydrogen in the indirect reduction zone and continue to descend to the soft melting zone. In the soft melting zone, as the temperature rises, the reduced slag iron is melted and drips into the dead material column area. After entering the dead material column area, the melted slag iron passes through the coke bed to undergo a very small amount of direct reduction reaction and carburization reaction, and then drips into the furnace to achieve slag iron separation, and finally discharged from the slag iron outlet. The molten iron output is 1t, and the slag output is 288.88kg / t;

[0052] Step 4: The gas and water vapor generated in the furnace are discharged from the gas outlet on the top of the furnace, including: 490.32m 3 / t water vapor, 579.75m 3 / t Hydrogen, 90.50m 3 / t Carbon monoxide, 19.14m 3 / t carbon dioxide is introduced into the furnace from the lower tuyere of the furnace waist and the working tuyere of the furnace hearth after being dehydrated, dusted and CO2 removed.

[0053] Example 3

[0054] This embodiment provides an ultra-low carbon ironmaking method integrating reduction, smelting and separation, comprising the following steps:

[0055] Step 1: Add iron ore and coke into the reduction smelting integrated furnace from the feed port in a layer of ore and coke distribution method. The ore input amount is 1633.55kg / t, and the coke input amount is 96.72kg / t. At this time, the ore-coke ratio is 17. After the raw materials are fully put in, a material column skeleton is formed on the upper part of the furnace body, and then a coke bed is pre-laid in the furnace hearth and furnace belly as a dead material column area;

[0056] Step 2: 170.11m2 of gas is transported into the furnace from the furnace body tuyere (4), furnace waist upper tuyere (4), and furnace waist lower tuyere (8) 3 Hydrogen, as the furnace tuyere is easily blocked by the charge, the furnace tuyere is divided into working tuyere (16) and spare tuyere (8). When the working tuyere is blocked, the blocked tuyere is drilled and unblocked, and then used as spare tuyere. At the same time, the spare tuyere is used as the working tuyere and hydrogen is sprayed into it. The amount of hydrogen transported from the furnace working tuyere (16) to the furnace is 593.19m 3 The total amount of hydrogen entering the furnace is 1103.52m 3 / t; the temperature of hydrogen sprayed from the furnace body tuyere is 350℃, the temperature of hydrogen sprayed from the upper tuyere of the furnace waist is 800℃, the temperature of hydrogen sprayed from the lower tuyere of the furnace waist is 900℃, and the temperature of hydrogen sprayed from the working tuyere of the furnace cylinder is 30℃. The integrated reduction and melting furnace is heated by plasma heating technology, and the heating power is gradually increased from top to bottom. After heating, the temperature of the indirect reduction zone is 200-1200℃, the temperature of the soft melting zone is 1200-1550℃, and the temperature of the dead material column zone is 1550-2000℃. In the entire integrated reduction and melting furnace, as the heating power gradually increases, the temperature in the furnace gradually increases from top to bottom, and the temperature shows a gradient distribution along the height direction of the furnace body;

[0057] Step 3: The iron oxides in the ore are reduced to metallic iron by high-temperature hydrogen in the indirect reduction zone and continue to descend to the soft melting zone. In the soft melting zone, as the temperature rises, the reduced slag iron is melted and drips into the dead material column area. After entering the dead material column area, the melted slag iron passes through the coke bed to undergo a very small amount of direct reduction reaction and carburization reaction, and then drips into the furnace to achieve slag iron separation, and finally discharged from the slag iron outlet. The molten iron output is 1t, and the slag output is 245.66kg / t;

[0058] Step 4: The gas and water vapor generated in the furnace are discharged from the gas outlet on the top of the furnace, including: 496.58m 3 / t water vapor, 631.28m 3 / t hydrogen, 98.3m 3 / t Carbon monoxide, 2.35m 3 / t carbon dioxide is input into the furnace from the working tuyere of the furnace and the tuyere of the furnace body after being dehydrated, dusted and CO2 removed.

[0059] Example 4

[0060] This embodiment provides an ultra-low carbon ironmaking method integrating reduction, smelting and separation, comprising the following steps:

[0061] Step 1: After the iron ore and coke are evenly mixed, they are added into the reduction smelting integrated furnace from the feed port. The ore input amount is 1633.55kg / t, and the coke input amount is 51.05kg / t. At this time, the ore-coke ratio is 32. After the raw materials are fully put in, a material column skeleton is formed on the upper part of the furnace body, and then a coke bed is pre-laid in the furnace hearth and the furnace belly as a dead material column area;

[0062] Step 2: 103.88m3 of gas is transported into the furnace from the furnace body tuyere (12), furnace waist upper tuyere (12), and furnace waist lower tuyere (24). 3 / t hydrogen, transported from the furnace working tuyere (28) to the furnace 903.74m 3 / t hydrogen, the total amount of hydrogen entering the furnace is 1215.38m 3 / t, among which, the temperature of hydrogen sprayed from the furnace body tuyere is 600℃, the temperature of hydrogen sprayed from the upper tuyere of the furnace waist is 600℃, the temperature of hydrogen sprayed from the lower tuyere of the furnace waist is 900℃, and the temperature of hydrogen sprayed from the working tuyere of the furnace cylinder is 30℃. The reduction and smelting integrated furnace is heated by electric energy, which gradually increases the heating power from top to bottom. After heating, the temperature of the indirect reduction zone is 200-1200℃, the temperature of the soft melting zone is 1200-1550℃, and the temperature of the dead material column zone is 1550-2000℃. In the entire reduction and smelting integrated furnace, as the heating power gradually increases, the temperature in the furnace gradually increases from top to bottom, and the temperature presents a gradient distribution along the height direction of the furnace body;

[0063] Step 3: The iron oxides in the ore are reduced to metallic iron by high-temperature hydrogen in the indirect reduction zone and continue to descend to the soft melting zone. In the soft melting zone, as the temperature rises, the reduced slag iron is melted and drips into the dead material column area. After entering the dead material column area, the melted slag iron passes through the coke bed to undergo a very small amount of direct reduction reaction and carburization reaction, and then drips into the furnace to achieve slag iron separation, and finally discharged from the slag iron outlet. The molten iron output is 1t, and the slag output is 192.34kg / t;

[0064] Step 4: The gas and water vapor generated in the furnace are discharged from the gas outlet on the top of the furnace, including: 543.62m 3 / t water vapor, 657.79m 3 / t hydrogen, 81.49m 3 / t Carbon monoxide, 1.16m 3 / t carbon dioxide is input into the furnace from the furnace body tuyere after water removal, dust removal and CO2 removal.

[0065] The above are only preferred embodiments of the present invention, and are not intended to limit the implementation methods and protection scope of the present invention. Those skilled in the art should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the contents of the specification of the present invention should be included in the protection scope of the present invention.

Claims

1. An ultra-low carbon ironmaking method integrating reduction and smelting, characterized in that: The following steps are involved: Step 1: Add iron ore and coke into the ironmaking furnace from the feed port and pile them up inside, and pre-lay a coke bed in the furnace hearth and furnace belly as a dead material column area; Step 2: hydrogen is transported into the ironmaking furnace from the tuyere, and gradient heating is performed on the reduction zone, soft melting zone and dead material column zone in the furnace; Step 3: After hydrogen enters the furnace, it reacts with iron ore in the reduction zone, and iron oxides are reduced to metallic iron; the reduced metallized charge descends to the soft melting zone, where it is melted and drips to the dead material column area, where the molten slag iron passes through the coke bed to undergo carburization reaction, then drips to the furnace to achieve slag iron separation, and is finally discharged from the slag iron outlet; Step 4: The gas and water vapor generated in the furnace are discharged from the gas outlet on the furnace top, and after being dehydrated, dusted and CO2 removed, they are circulated through the tuyere and re-introduced into the furnace.

2. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 1, characterized in that: In step 1, the mass ratio of iron ore to coke added into the ironmaking furnace from the feed port is 12-32:1, and the amount of coke used is 50-150kg / t.

3. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 1 or 2, characterized in that: Iron ore and coke are added into the ironmaking furnace from the feed inlet in a layered or mixed manner.

4. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 1, characterized in that: The tuyere of the ironmaking furnace includes the furnace body tuyere, the upper furnace waist tuyere, the lower furnace waist tuyere and the furnace hearth tuyere, and the number of each type of tuyere is 4-48.

5. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 4, characterized in that: The furnace tuyere is divided into working tuyere and standby tuyere. When the working tuyere of the furnace is unobstructed, hydrogen is transported into the furnace from all tuyere of the ironmaking furnace.

6. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 5, characterized in that: When the working air outlet is blocked, the spare air outlet is activated as the working air outlet and hydrogen is sprayed inward, and the blocked air outlet is drilled and unblocked, and then used as a spare air outlet after unblocking, or oxygen-enriched hot air is intermittently sprayed into the blocked air outlet for chemical combustion unblocking, and then used as a spare air outlet after unblocking.

7. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 5 or 6, characterized in that: When hydrogen is sprayed, the temperature of hydrogen sprayed from the furnace body tuyere is 150-600℃, the temperature of hydrogen sprayed from the upper and lower tuyere of the furnace waist is 600-1200℃, and the temperature of hydrogen sprayed from the furnace hearth tuyere is 30-1500℃.

8. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 1, characterized in that: When gradient heating is performed in step 2, the heating power is gradually increased from top to bottom, so that the temperature of the indirect reduction zone is 200-1200°C, the temperature of the soft melting zone is 1200°C-1550°C, and the temperature of the dead material column zone is 1550°C-2000°C.

9. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 1, characterized in that: After the slag iron passes through the coke bed in step 3 to undergo carburizing reaction, the mass fraction of iron in the molten iron is 94-96%, and the mass fraction of carbon is 3-6%.

10. The ultra-low carbon ironmaking method integrating reduction and smelting according to claim 4, characterized in that: In step 4, the gas exhausted from the furnace is treated and then sprayed into the furnace from one or more of the four types of tuyere.

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