Steel smelting system and method based on hydrogen-rich reducing gas injection

Abstract

Disclosed in the present invention are a steel smelting system and method based on hydrogen-rich reducing gas injection. The steel smelting system comprises a blast furnace and a hydrogen-rich reducin

Description

Field of the Invention The invention relates to steel smelting, in particular to a steel smelting system and method based on hydrogen-rich reducing gas injection. Description of the Prior art In 2022, China's crude steel output reached 1.013 billion tons. Among this, the blast furnace-converter long-process technology based on carbon metallurgy and iron ore accounted for approximately 90% of the national crude steel output. Having undergone over a century of technological development and innovation, the blast furnace ironmaking process features mature technology, large production capacity and high efficiency. In light of China's resource endowment characterized by abundant coal, deficient oil and scarce natural gas, it is anticipated that blast furnaces will remain the mainstream ironmaking equipment to underpin China's enormous demand for steel materials in the coming decades. However, due to the limitations of its own process, technology and equipment conditions, the blast furnace ironmaking method has the following two prominent problems. Firstly, coal and coke required for blast furnace ironmaking are used as energy sources and reducing agents to assist the reduction, melting and smelting of iron ore (in 2022, the carbonaceous fuel ratio of the national blast furnace ironmaking process was 527.09 kg / t), which leads to high carbon emissions per ton of molten iron produced. At present, the carbon emissions per ton of steel in the long process are about 1.8-2.5 tons, making it the process with the largest CO2 emissions in the steel production process, accounting for approximately 70%-90% of the total CO2 emissions m the entire steel production. Therefore, in order to address global climate change and achieve the policy goals of "carbon neutrality and carbon peaking" in the iron and steel industry, developing low-carbon smelting technologies, especially for the blast furnace process with the largest CO2 emissions, has become an important path to achieve significant emission reduction in the steel manufacturing process. At present, the main fuel, framework and reducing agent for molten iron smelting in blast furnaces is coke. Coke is obtained by dry distillation of coal at a high temperature of about 1000°C in a coking plant. The coking process produces a large amount of harmful chemical pollutants and has high costs. Moreover, to ensure the air permeability of the blast furnace, the crushed coke and coke breeze produced during the coking process generally cannot directly enter the blast furnace. Reducing the coke ratio of blast furnaces is the key to blast furnace energy conservation. In traditional blast furnace smelting, low-rank coal powder is mainly injected into the blast furnace to partially replace coke. However, a large amount of coal powder injection will bring a series of adverse effects to blast furnace smelting. For example, coal powder will undergo a series of physical and chemical changes such as heating, decomposition, combustion and slag formation inside the blast furnace, making the reaction in the raceway complex and the operation difficult; with the increase of coal powder injection volume, the cohesive zone expands and coke is severely damaged, resulting in coal powder injection being restricted by coke quality; the increase of unbumed coal powder will further deteriorate the working state of the cohesive zone and slag formation zone of the blast furnace; in addition, oxygen-enriched and large-volume coal powder injection will also cause the blast furnace to present a "cold top and hot bottom" phenomenon. In addition, blast furnace smelting will produce blast furnace top gas, which contains CO and CO2. To recover CO from blast furnace gas, the blast furnace gas will be re-injected into the blast furnace, but before that, it is necessary to first remove CO2 from the blast furnace gas, which is also a difficult problem. Hydrogen has the advantages of green renewability, high reducibility and cleanliness without pollution. Using a large amount of hydrogen instead of carbon as fuel and reducmg agent in the metallurgical process, the reaction product is water. Compared with traditional carbon metallurgy, it can fundamentally reduce carbon emissions and achieve the goal of clean production. Compared with coal, the ratio of H2 / CO in waste plastic gasification products is much higher than that when coal powder is injected, which is more conducive to the high-temperature reduction of iron oxides. However, the direct injection of plastic into blast furnaces is still in the research stage. Another clean and renewable energy source—biomass pellets, has high calorific 3 value and the characteristics of "carbon cycle and carbon neutrality" itself. When injected into the blast furnace, it can not only make up for the heat loss in the lower part of the blast furnace caused by hydrogen, but also save coal resources, reduce the possibility that unburned coal powder affects the air permeability of the blast furnace, and will not produce excess carbon emissions. However, the existing traditional tuyeres cannot realize the mixed injection of gas and biomass pellets. Summary of the Invention In view of the above defects of the prior art, the present invention provides a steel smelting system based on hydrogen-rich reducing gas injection, which includes a blast furnace and a hydrogen-rich reducing gas prefabrication furnace; hydrogen-rich reducing gas from the hydrogen-rich reducing gas prefabrication furnace and pure hydrogen are injected into the blast furnace; the generated blast furnace top gas is recycled into the hydrogen-rich reducing gas prefabrication furnace for decarbonization; the charge column in the hydrogen-rich reducing gas prefabrication furnace includes coke breeze, biomass pellets and waste plastic pellets, and dry coal powder and pure oxygen are also injected into the hydrogen-rich reducing gas prefabrication furnace to prepare hydrogen-rich reducing gas. Further, the blast furnace includes an ironmaking blast furnace, a blast furnace for cast iron, and a blast furnace for ferroalloys. Further, the dry coal powder is hydrogen-rich coal powder. 4 Further, the pure hydrogen is prepared by electrolyzing water using green electricity generated from blast furnace gas, converter gas power generation, photovoltaic power, wind power, nuclear power, hydropower and grid valley electricity, or by reforming and purifying hydrogen-rich gases such as coke oven gas and natural gas. Further, the molten iron produced by the blast furnace is supplied to primary steelmaking furnaces including converters and electric arc furnaces for producing carbon structural steel, alloy structural steel, low-alloy high-strength structural steel, carbon tool steel, alloy tool steel, high-speed tool steel, high-carbon steel castings, high-carbon iron castings, stainless steel, and special-purpose steel materials added with specific alloying elements including rare earths; the special-purpose steel materials include marine corrosion-resistant steel; and profiles, plates, pipes, bars and wires rolled from the above-mentioned steel materials. Further, a double-tube spiral distributor is adopted at the feed inlet of the hydrogen-rich reducing gas prefabrication furnace, which includes an outer tube; the upper part inside the outer tube is a spiral material channel, and the lower part is an inner tube; the inner tube extends downward beyond the outer tube, and the length of the inner tube is set such that its outlet is submerged m the charge column in the hydrogen-rich reducing gas prefabrication furnace; a plurality of pressure equalizing holes are arranged on the part of the inner tube extending beyond the outer tube to balance the pressure between the inner tube and the furnace. The present invention also provides a steel smelting method based on hydrogen-rich reducing gas injection, which comprises the following steps: (1) Adding coke breeze, biomass pellets and waste plastic pellets into a hydrogen-rich reducing gas prefabrication furnace, and simultaneously injecting dry coal powder and pure oxygen for combustion to prepare hydrogen-rich reducing gas; (2) Mixing the hydrogen-rich reducing gas from the hydrogen-rich reducing gas prefabrication furnace with pure hydrogen and then injecting the mixture into a blast furnace; (3) Introducing the generated blast furnace top gas into the hydrogen-rich reducing gas prefabrication furnace for decarbonization; (4) Simultaneously injecting pure oxygen into the blast furnace; (5) Supplying the molten iron produced by the blast furnace to primary steelmaking furnaces including converters and electric arc furnaces for producing carbon structural steel, alloy structural steel, low-alloy high-strength structural steel, carbon tool steel, alloy tool steel, high-speed tool steel, high-carbon steel castings, high-carbon iron castings and stainless steel. Further, the dry coal powder is hydrogen-rich coal powder. Further, the pure hydrogen is prepared by electrolyzing water using green electricity generated from blast furnace gas, converter gas power generation, photovoltaic power, wind power, nuclear power, hydropower and grid valley electricity, or by reforming and purifying hydrogen-rich gases such as coke oven gas and natural gas. Further, a double-tube spiral distributor is adopted at the feed inlet of the hydrogen-rich reducing gas prefabrication furnace, which includes an outer tube; the upper part inside the outer tube is a spiral material channel, and the lower part is an inner tube; the inner tube extends downward beyond the outer tube, and the length of the inner tube is set such that its outlet is submerged in the charge column in the hydrogen-rich reducing gas prefabrication furnace; meanwhile, a plurality of pressure equalizing holes are arranged on the part of the inner tube extending beyond the outer tube to balance the pressure between the inner tube and the furnace; the mixture of coke breeze, biomass pellets and waste plastic pellets enters the spiral material channel from above; in the process of falling along the spiral material channel, due to the high density of coke breeze, its movement trajectory is closer to the outer tube under the action of inertia, while biomass pellets and waste plastic pellets have low density, and their movement trajectory is closer to the inner tube; after passing through the spiral material channel in this way, most of the coke breeze enters the furnace through the shorter outer tube and participates in the reaction in the furnace earlier, while most of the biomass pellets and waste plastic pellets enter the furnace through the longer inner tube and participate in the reaction in the furnace later. The present invention adopts a hydrogen-rich reducing gas prefabrication furnace, which can prefabricate resources such as coal powder, coke breeze, biomass pellets and waste plastic pellets that are not suitable for direct entry into the blast 7 furnace but are conducive to reducing the energy consumption of the blast furnace into hydrogen-rich reducing gas, which can then be injected into the blast furnace together with hydrogen. Among them, prefabricating coal powder into hydrogen-rich reducing gas can eliminate the adverse impact of coal injection on the blast furnace condition; prefabricating coke breeze, biomass pellets and waste plastic pellets into hydrogen-rich reducing gas can realize full utilization and recycling of resources. Introducing blast furnace gas into the hydrogen-rich reducing gas prefabrication furnace can conveniently realize decarbonization of blast furnace gas. More importantly, through the comprehensive treatment and unified conversion of the above various resources into hydrogen-rich reducing gas by the hydrogen-rich reducing gas prefabrication furnace, when mixed and injected with pure hydrogen in the subsequent process, the ratio of CO to H2 can be dynamically adjusted by the control system according to the composition change in the hydrogen-rich reducing gas, so as to realize the control of the reducing atmosphere and heat in the blast furnace, thereby achieving replaceable control of the furnace ore. In summary, through the unified recovery, conversion and utilization of resources, the present invention reduces the energy consumption of the blast furnace, thereby reducing carbon emissions from steel smelting. The present invention also provides a double-tube spiral distributor, which can make the consumption rate of biomass pellets and waste plastic pellets with fast combustion converge with that of coke breeze with slow combustion. In this way, during the prefabrication process of hydrogen-rich reducing gas, the raw material distribution of the charge column in the furnace is more uniform, and the temperature in the furnace is more balanced. The following description will further elucidate the concept, specific structure, and technical effects of the present invention m conjunction with the accompanying drawings, to fully illustrate the objectives, features, and advantages of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic diagram of a steel smelting system based on hydrogen-rich reducing gas injection in a preferred embodiment of the present invention; Figure 2 is a schematic diagram of a hydrogen-rich reducing gas prefabrication furnace in a preferred embodiment of the present invention; Figure 3 is a schematic diagram of a double-tube spiral distributor in a preferred embodiment of the present invention; Figure 4 is a schematic diagram of a hydrogen-rich reducing gas prefabrication furnace using the double-tube spiral distributor shown in Figure 3. DETAILED DESCRIPTION OF THE EMBODIMENTS A plurality of preferred embodiments of the present invention are described below with reference to the drawings, which makes its technical content more clear and convenient to understand. The present invention may be embodied in many different forms of embodiments, and the scope of protection of the present invention is not limited to the embodiments set forth herein. In a preferred embodiment of the present invention, the steel smelting system based on hydrogen-rich reducing gas injection is shown in Figure 1, which includes a blast furnace 2 and a hydrogen-rich reducing gas prefabrication furnace 1. Hydrogen-rich reducing gas from the hydrogen-rich reducing gas prefabrication furnace 1, hydrogen obtained by green power electrolysis and pure oxygen are injected into the blast furnace 2 for molten iron smelting. Then the molten iron produced by the blast furnace 2 enters the steelmaking process and is supplied to primary steelmaking furnaces such as converters and electric arc furnaces for producing carbon structural steel, alloy structural steel, low-alloy high-strength structural steel, carbon tool steel, alloy tool steel, high-speed tool steel, high-carbon steel castings, high-carbon iron castings and stainless steel. To prefabricate hydrogen-rich reducmg gas, coke breeze, biomass pellets and waste plastic pellets are added from the top of the hydrogen-rich reducing gas prefabrication furnace 1, dry coal powder and industrial pure oxygen are injected from the furnace body of the hydrogen-rich reducing gas prefabrication furnace 1, and the blast furnace gas from the blast furnace 2 is also introduced into the hydrogen-rich reducing gas prefabrication furnace 1. The dry coal powder is preferably hydrogen-rich coal powder. In a preferred embodiment of the present invention, the hydrogen-rich reducing gas prefabrication furnace 1 is shown in Figure 2. The lower part of the furnace body is provided with ash and slag 13, and the middle part is provided with coke breeze 11, biomass pellets and waste plastic pellets 12. Meanwhile, coal powder and industrial pure oxygen are injected for combustion, generating hydrogen-rich reducing gases such as CO and H2, which are discharged from the upper part of the furnace body of the hydrogen-rich reducing gas prefabrication furnace 1 and injected into the blast furnace 2. The CO2 in the blast furnace gas introduced into the hydrogen-rich reducing gas prefabrication furnace 1 reacts with the coke breeze in the furnace and is reduced to CO. The present invention adopts a hydrogen-rich reducing gas prefabrication furnace, which can prefabricate resources such as coal powder, coke breeze, biomass pellets and waste plastic pellets—resources that are not suitable for direct entry into the blast furnace but are conducive to reducing blast furnace energy consumption—into hydrogen-rich reducing gas, which can then be injected into the blast furnace together with hydrogen. Among them, prefabricating coal powder into hydrogen-rich reducing gas can eliminate the adverse effects of coal powder injection on blast furnace conditions; prefabricating coke breeze, biomass pellets and waste plastic pellets into hydrogen-rich reducing gas can realize full utilization and recovery of resources. Introducing blast furnace gas into the hydrogen-rich reducing gas prefabrication furnace can conveniently achieve decarbonization of blast furnace gas. More importantly, through the comprehensive treatment of the above-mentioned various resources by the hydrogen-rich reducing gas prefabrication furnace and their unified conversion into hydrogen-rich reducing gas, it can be realized that during the subsequent mixed injection with pure hydrogen, the control system can dynamically adjust the ratio of CO and H2 according to the composition changes in the hydrogen-rich reducing gas, thereby realizing the control of the reducing atmosphere and heat of the blast furnace, and thus realizing control of the blast furnace conditions. Compared with coke breeze, biomass pellets and waste plastic pellets have lower density and faster combustion rate. If the three are uniformly distributed, it is likely to cause coke breeze agglomeration in the charge column of the hydrogen-rich reducing gas prefabrication furnace, leading to uneven temperature in the furnace, fluctuations in furnace conditions, and even safety accidents. In a further embodiment of the present invention as shown in Figures 3 and 4, a double-tube spiral distributor is adopted at the feed inlet of the hydrogen-rich reducing gas prefabrication furnace 1, which includes an outer tube 2. The upper part inside the outer tube 2 is a spiral material channel 3, and the lower part is an inner tube 4. The inner tube 4 extends downward beyond the outer tube 2, and its length is such that its outlet is submerged in the charge column in the hydrogen-rich reducing gas prefabrication furnace. The mixture of coke breeze, biomass pellets and waste plastic pellets enters the spiral material channel 3 from above. In the process of falling along the spiral material channel, due to the high density of coke breeze, its movement trajectory is closer to the outer tube under the action of inertia, while biomass pellets and waste plastic pellets have low density, and their movement trajectory is closer to the inner tube. After passing through the spiral material channel in this way, most of the coke breeze enters the furnace through the shorter outer tube and participates in the reaction in the furnace earlier, while most of the biomass pellets and waste plastic pellets enter the furnace through the longer inner tube, and the outlet of the inner tube is submerged in the charge column, so they participate in the reaction in the furnace later. Thus, although they enter the furnace at the same time, the starting time of participating in the reaction is different, so that the consumption rate of biomass pellets and waste plastic pellets with faster combustion tends to be the same as that of coke breeze with slower combustion. In this way, during the prefabrication process of hydrogen-rich reducing gas, the raw material distribution of the charge column in the furnace is more uniform, and the temperature in the furnace is more balanced. The preferred specific embodiments of the present invention have been described in detail above. It should be understood that those of ordinary skill in the art can make many modifications and changes according to the concept of the present invention without creative labor. Therefore, all technical solutions that can be obtained by those skilled in the art in this technical field through logical analysis, reasoning or limited experiments on the basis of the prior art according to the concept of the present invention shall fall within the protection scope determined by the claims.

Claims

1. A steel smelting system based on hydrogen-rich reducing gas injection, characterized m that it includes a blast furnace and a hydrogen-rich reducing gas prefabrication furnace; hydrogen-rich reducing gas from the hydrogen-rich reducing gas prefabrication furnace and pure hydrogen are injected into the blast furnace; the generated blast furnace top gas is recycled into the hydrogen-rich reducing gas prefabrication furnace for decarbonization; the charge column in the hydrogen-rich reducing gas prefabrication furnace includes coke breeze, biomass pellets and waste plastic pellets, and dry coal powder and pure oxygen are also injected into the hydrogen-rich reducing gas prefabrication furnace to prepare hydrogen-rich reducing gas.

2. The steel smelting system based on hydrogen-rich reducing gas injection according to claim 1, wherein the blast furnace includes an ironmaking blast furnace, a blast furnace for cast iron, and a blast furnace for ferroalloys.

3. The steel smelting system based on hydrogen-rich reducing gas injection according to claim 1, wherein the dry coal powder is hydrogen-rich coal powder.

4. The steel smelting system based on hydrogen-rich reducing gas injection according to claim 1, wherein the pure hydrogen is prepared by electrolyzing water using green electricity generated from blast furnace gas, converter gas power generation, photovoltaic power, wind power, nuclear power, hydropower and grid valley electricity, or by reforming and purifying hydrogen-rich gases such as coke oven gas and natural gas.

5. The steel smelting system based on hydrogen-rich reducing gas injection according to claim 1, wherein the molten iron produced by the blast furnace is supplied to primary steelmaking furnaces including converters and electric arc furnaces for producing carbon structural steel, alloy structural steel, low-alloy high-strength structural steel, carbon tool steel, alloy tool steel, high-speed tool steel, high-carbon steel castings, high-carbon iron castings, stainless steel, and special-purpose steel materials added with specific alloying elements including rare earths; the special-purpose steel materials include marine corrosion-resistant steel; and profiles, plates, pipes, bars and wires rolled from the above-mentioned steel materials.

6. The steel smelting system based on hydrogen-rich reducing gas injection according to claim 1, wherein a double-tube spiral distributor is adopted at the feed inlet of the hydrogen-rich reducing gas prefabrication furnace, which includes an outer tube; the upper part inside the outer tube is a spiral material channel, and the lower part is an inner tube; the inner tube extends downward beyond the outer tube, and the length of the inner tube is set such that its outlet is submerged in the charge column in the hydrogen-rich reducing gas prefabrication furnace; a plurality of pressure equalizing holes are arranged on the part of the inner tube extending beyond the outer tube to balance the pressure between the inner tube and the furnace.

7. A steel smelting method based on hydrogen-rich reducing gas mj ection, characterized m that it comprises the following steps:(1) adding coke breeze, biomass pellets and waste plastic pellets into a hydrogen-rich reducing gas prefabrication furnace, and simultaneously injecting dry coal powder and pure oxygen for combustion to prepare hydrogen-rich reducing gas;(2) mixing the hydrogen-rich reducing gas from the hydrogen-rich reducing gas prefabrication furnace with pure hydrogen and then injecting the mixture into a blast furnace;(3) introducing the generated blast furnace top gas into the hydrogen-rich reducing gas prefabrication furnace for decarbonization;(4) simultaneously injecting pure oxygen into the blast furnace;(5) supplying the molten iron produced by the blast furnace to primary steelmaking furnaces including converters and electric arc furnaces for producing carbon structural steel, alloy structural steel, low-alloy high-strength structural steel, carbon tool steel, alloy tool steel, high-speed tool steel, high-carbon steel castings, high-carbon iron castings and stainless steel.

8. The steel smelting method based on hydrogen-rich reducing gas injection according to claim 7, wherein the dry coal powder is hydrogen-rich coal powder.

9. The steel smelting method based on hydrogen-rich reducing gas injection according to claim 7, wherein the pure hydrogen is prepared by electrolyzing water using green electricity generated from blast furnace gas, converter gas power generation, photovoltaic power, wind power, nuclear power, hydropower and grid valley electricity, or by reforming and purifying hydrogen-rich gases such as coke oven gas and natural gas.

10. The steel smelting method based on hydrogen-rich reducing gas injection according to claim 7, wherein a double-tube spiral distributor is adopted at the feed inlet of the hydrogen-rich reducing gas prefabrication furnace, which includes an outer tube; the upper part inside the outer tube is a spiral material channel, and the lower part is an inner tube; the inner tube extends downward beyond the outer tube, and the length of the inner tube is set such that its outlet is submerged in the charge column in the hydrogen-rich reducing gas prefabrication furnace; meanwhile, a plurality of pressure equalizing holes are arranged on the part of the inner tube extending beyond the outer tube to balance the pressure between the inner tube and the furnace; the mixture of coke breeze, biomass pellets and waste plastic pellets enters the spiral material channel from above; in the process of falling along the spiral material channel, due to the high density of coke breeze, its movement trajectory is closer to the outer tube under the action of inertia, while biomass pellets and waste plastic pellets have low density, and their movement trajectory is closer to the inner tube; after passing through the spiral material channel in this way, most of the coke breeze enters the furnace through the shorter outer tube and participates in the reaction in the furnace earlier, while most of the biomass pellets and waste plastic pellets enter the furnace through the longer inner tube and participate in the reaction in the furnace later.INTERNATIONAL SEARCH REPORT International application No. PCT / CN2024 / 104326A. CLASSIFICATION OF SUBJECT MATTERC21B 7 / 00(2006.01)i; C21B 5 / 00(2006.01)i; C21B 5 / 06(2006.01)i; F27D 3 / 08(2006.01)iAccording to International Patent Classification (IPC) or to both national classification and IPCB. FIELDS SEARCHEDMinimum documentation searched (classification system followed by classification symbols) IPC: C21B,F21D,C10JDocumentation searched other than minimum documentation to the extent that such documents are included in the fields searchedElectronic data base consulted during the international search (name of data base and, where practicable, search terms used)CNTXT, DWPI, ENTXTC, DWPI, CNKI: S., W, BA, B,, KW. in A, AfW, A, M-. hydrogen+, blast furnace, coal gas, coke, European smelting furnace, gas preparat+, gasification furnace, biomass+, plasticDOCUMENTS CONSIDERED TO BE RELEVANTCategory* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. PX CN 117431352 A (CHANGLI COUNTY XINGGUO PRECISION MACHINERY PARTS CO., LTD. et al.) 23 January 2024 (2024-01-23) claims 1-10 1-10 A CN 114854455 A (UNIVERSITY OF SCIENCE AND TECHNOLOGY BEIJING) 05 August 2022 (2022-08-05) claim 1, and description, paragraphs 0007 and 0043 1-10 A CN 114752720 A (BEIJING GAOCHUANG ZHIXIN METALLURGICAL TECHNOLOGY CO., LTD.) 15 July 2022 (2022-07-15) entire document 1-10 A CN 113005250 A (HEBEI YANGANG TECHNOLOGY CO., LTD.) 22 June 2021 (2021-06-22) entire document 1-10 A CN 115216346 A (SHANGHAI LANRUI ENVIRONMENTAL PROTECTION ENERGY TECHNOLOGY CO., LTD.) 21 October 2022 (2022-10-21) entire document 1-10| | Further documents are listed in the continuation of Box C. | J | See patent family annex.* Special categories of cited documents: “T” later document published after the international filing date or priority “A” document defining the general state of the art which is not considered date and not in conflict with the application but cited to understand the to be of particular- relevance principle or theory underlying the invention “D” document cited by the applicant in the international application “X” document of particular- relevance; the claimed invention cannot be “E” earlier application orpatent but published on or after the international considered novel or cannot be considered to involve an inventive step filing date when the document is taken alone “L” document which may throw doubts on priority claim(s) or which is “Y” document of particular relevance; the claimed invention cannot be cited to establish the publication date of another citation or other considered to involve an inventive step when the document is special reason (as specified) combined with one or more other such documents, such combination “O” document referring to an oral disclosure, use, exhibition or other being obvious to a person skilled in the art means document member of the same patent family “P” document published prior to the international filing date but later than the priority date claimed Date of the actual completion of the international search 05 September 2024 Date of mailing of the international search report 11 September 2024 Name and mailing address of the ISA / CN China National Intellectual Property Administration (ISA / CN) China No. 6, Xitucheng Road, Jimenqiao, Haidian District, Beijing 100088 Authorized officer Telephone No.INTERNATIONAL SEARCH REPORT International application No. PCT / CN2024 / 104326C. DOCUMENTS CONSIDERED TO BE RELEVANTCategory* Citation of document, with indication, where appropriate, of the relevant passages Relevant to claim No. A CN 106636508 A (NORTH CHINA UNIVERSITY OF SCIENCE AND TECHNOLOGY) 10 May 2017 (2017-05-10) entire document 1-10 A CN 114438270 A (HBIS GROUP CO., LTD. et al.) 06 May 2022 (2022-05-06) entire document 1-10 A CN 102220443 A (MAANSHAN IRON &STEEL CO., LTD.) 19 October 2011 (2011-10-19) entire document 1-10 A JP 2012251186 A (SUMITOMO METAL INDUSTRIES, LTD.) 20 December 2012 (2012-12-20) entire document 1-10 A WO 2017111415 Al (POSCO) 29 June 2017 (2017-06-29) entire document 1-10 A WO 2011108546 Al (JFE STEEL CORP, et al.) 09 September 2011 (2011-09-09) entire document 1-10INTERNATIONAL SEARCH REPORT Information on patent family membersInternational application No.Patent document cited in search report Publication date (day / month / year) Patent family member(s) Publication date (day / month / year) CN 117431352 A 23 January 2024 None CN 114854455 A 05 August 2022 None CN 114752720 A 15 July 2022 None CN 113005250 A 22 June 2021 None CN 115216346 A 21 October 2022 None CN 106636508 A 10 May 2017 None CN 114438270 A 06 May 2022 None CN 102220443 A 19 October 2011 None JP 2012251186 A 20 December 2012 JP 5598423 B2 01 October 2014 WO 2017111415 Al 29 June 2017 KR 20170075852 A 04 July 2017 KR 101758521 Bl 17 July 2017 JP 2019501103 A 17 January 2019 JP 6538281 B2 03 July 2019 EP 3395758 Al 31 October 2018 EP 3395758 A4 02 January 2019 WO 2011108546 Al 09 September 2011 KR 20120105562 A 25 September 2012 KR 101464056 Bl 21 November 2014 EP 2543743 Al 09 January 2013 EP 2543743 A4 08 June 2016 EP 2543743 Bl 29 November 2017

Images