Multi-material mixed supply system of smelting reduction furnace and supply quantity distribution method

Abstract

The invention relates to the technical field of smelting reduction smelting, and discloses a multi-material mixed supply system of a smelting reduction furnace and a supply quantity distribution method. The multiple injection modules comprise a pulverized coal injection module, a lime powder injection module, an iron-containing material injection module and a magnesium-containing flux injection module, the pulverized coal injection module is used for injecting pulverized coal into the smelting reduction furnace, and the lime powder injection module is used for injecting quicklime powder into the smelting reduction furnace; the iron-containing material injection module is used for injecting an iron-containing material into the smelting reduction furnace, and the magnesium-containing flux injection module is used for injecting a magnesium-containing flux into the smelting reduction furnace. The problem of furnace condition deterioration caused by slag magnesium-aluminum ratio adjustment lag under special furnace conditions can be relieved.

Description

Technical Field

[0001] This application relates to the field of molten reduction smelting, specifically to a multi-material mixing and supply system and a supply quantity allocation method for a molten reduction furnace. Background Technology

[0002] The molten reduction process uses iron bath molten reduction smelting with fine ore and non-coking coal powder. Compared with the blast furnace process, it does not require coking coal or sintering and pelletizing processes, and has the advantages of short technical process, low pollution emissions and wide applicability of raw materials.

[0003] Currently, Chinese invention patent application CN201922067264.X discloses a feeding and conveying device for a molten reduction furnace, including a hot ore bin, an intermediate tank, a blower tank, a screw feeder, a quicklime powder bin, a rotary feeder, a dry coal bin, and a conveying pipeline. The outlet of the hot ore bin is connected to the conveying pipeline sequentially through the intermediate tank, the blower tank, and the screw feeder. The outlet of the quicklime powder bin is connected to the conveying pipeline sequentially through the intermediate tank, the blower tank, and the rotary feeder. The outlet of the dry coal bin is connected to the conveying pipeline sequentially through the intermediate tank, the blower tank, and the rotary feeder. This patent mixes the quicklime powder leaving the rotary feeder with coal powder nearby, and premixes the iron ore powder and dolomite, so that the mixture of iron ore powder, dolomite, quicklime powder, and coal powder is conveyed to the furnace front and injected into the molten reduction furnace through two spray guns.

[0004] With the advancement of the "dual carbon" goals, the metallurgical industry is placing higher demands on the raw material adaptability (such as low-grade ore and carbon-containing waste) and low-carbon operation of smelting reduction processes. Regarding the aforementioned technologies, the inventors believe that existing smelting reduction furnace material supply methods are insufficient to meet the needs for efficient and flexible material supply under different furnace conditions. Issues include low carbon content in molten iron under high ore injection rates, low carburization efficiency in molten iron, insufficient pulverized coal injection capacity to meet pulverized coal supply requirements under high ore injection rates, and the inability to address the issue of ore reduction treatment if a pulverized coal injection line fails. Furthermore, the current pre-mixing of iron ore powder and dolomite affects the timely control of the slag magnesium-aluminum ratio under special furnace conditions. Due to the pre-mixed storage in the hot ore bin and pretreatment system, furnace condition adjustments have a 4-5 hour lag, easily leading to slag condition deterioration. This is especially problematic during the stage of increasing the ore injection rate and when ore reduction treatment is required in case of sudden failures, severely impacting furnace condition recovery and directly affecting process stability and production efficiency. Summary of the Invention

[0005] To alleviate the aforementioned technical problems, this application provides a multi-material mixing and supply system for a melting reduction furnace.

[0006] This application provides a multi-material mixing and feeding system for a melting reduction furnace, which adopts the following technical solution: A multi-material mixing and supply system for a molten reduction furnace includes multiple independent injection modules. These injection modules include a pulverized coal injection module, a lime powder injection module, an iron-containing material injection module, and a magnesium-containing flux injection module. The pulverized coal injection module injects pulverized coal into the molten reduction furnace; the lime powder injection module injects quicklime powder into the molten reduction furnace; the iron-containing material injection module injects iron-containing materials into the molten reduction furnace; and the magnesium-containing flux injection module injects magnesium-containing flux into the molten reduction furnace. The iron-containing materials include iron ore powder. The magnesium-containing flux includes lightly calcined dolomite and / or steel slag. The lime powder injection module is used to inject calcium-containing solvent. The injection module includes an injection device, a conveying pipeline, and a spray gun anti-clogging device. The conveying pipeline includes an injection pipeline and a self-circulation pipeline. The inlet of the injection device is connected to the silo. The outlet of the injection device is connected to the injection pipeline. The outlet of the injection device is connected to the silo through the self-circulation pipeline. The end of the injection pipeline away from the injection device is connected to the spray gun. The spray gun anti-clogging device is connected to the injection pipeline near the spray gun.

[0007] By adopting the above technical solutions, four independent injection channels are used to achieve precise decoupled control of iron material, pulverized coal, calcium-containing flux, and magnesium-containing flux. By adding a magnesium-containing flux injection system, the flexibility and timeliness of slag magnesium-aluminum ratio adjustment under special furnace conditions are improved. This solves the problem of pre-mixing iron-containing materials with dolomite in the existing process, which leads to a lag in slag magnesium-aluminum ratio adjustment under special furnace conditions and causes furnace condition deterioration. At the same time, pulverized coal and lime powder are injected separately through separate pipelines, which improves the activity of lime powder entering the furnace. This solves the problem of pre-mixing hot pulverized coal and cold lime powder, which causes the moisture (about 2%) in the pulverized coal to react with the lime powder, affecting the activity of lime powder entering the furnace and causing the lime powder to clump and block the pipeline. The material in the injection device is circulated and injected into the silo to avoid the deposition and agglomeration of pulverized coal and flux, and the material is adhered to the inner wall of the injection device. In the event of a fault shutdown of the injection module or blockage of the injection pipeline, the self-circulation system can withdraw all the material in the 30-meter conveying pipeline back to the silo within 120 seconds.

[0008] Optionally, the mixed supply system includes 2-4 iron-containing material injection modules, the iron-containing material injection pipeline includes an iron-containing material pipeline shut-off valve and a spray gun isolation valve, the outlet of the iron-containing material injection device is connected to the iron-containing material pipeline shut-off valve, and the iron-containing material pipeline shut-off valve is connected to the solid material spray gun through the spray gun isolation valve.

[0009] Optionally, the mixed supply system includes 4-6 pulverized coal injection modules. The pulverized coal injection pipeline includes a pulverized coal pipeline shut-off valve, a spray gun switching valve, and a spray gun isolation valve. The spray gun switching valve includes a first spray gun switching valve and a second spray gun switching valve. The spray gun isolation valve includes a first spray gun isolation valve and a second spray gun isolation valve. The outlet of the pulverized coal injection device is connected to the pulverized coal pipeline shut-off valve. The pulverized coal pipeline shut-off valve is connected to the iron-containing material injection pipeline in sequence through the first spray gun switching valve and the first spray gun isolation valve. The pulverized coal pipeline shut-off valve is connected to the pulverized coal spray gun in sequence through the second spray gun switching valve and the second spray gun isolation valve.

[0010] By adopting the above technical solution, the pulverized coal pipeline shut-off valve is connected to the iron-containing material injection pipeline and the pulverized coal injection gun through the first injection gun switching valve, the first injection gun isolation valve, the second injection gun switching valve, and the second injection gun isolation valve. Depending on the furnace conditions, pulverized coal can be directly injected into the melting reduction furnace through the pulverized coal injection gun for separate supply, or it can be integrated into the iron-containing material injection pipeline and injected into the melting reduction furnace through the solid material injection gun, thereby improving the flexibility of material supply.

[0011] Optionally, the mixed supply system includes 1-2 magnesium flux injection modules. The magnesium flux injection pipeline includes a magnesium flux pipeline shut-off valve, a spray gun switching valve, and a spray gun isolation valve. The outlet of the magnesium flux injection device is connected to the magnesium flux pipeline shut-off valve. The magnesium flux pipeline shut-off valve is connected to the iron-containing material injection pipeline in sequence through the first spray gun switching valve and the first spray gun isolation valve. The magnesium flux pipeline shut-off valve is connected to the pulverized coal injection pipeline in sequence through the second spray gun switching valve and the second spray gun isolation valve.

[0012] By adopting the above technical solution, the magnesium flux pipeline shut-off valve is connected to the iron-containing material injection pipeline through the first spray gun switching valve and the first spray gun isolation valve, which can directly inject magnesium flux into the furnace, alleviating the problem of lag in furnace condition adjustment due to the premixed storage of hot ore bins and pretreatment systems; the magnesium flux pipeline shut-off valve is connected to the pulverized coal injection pipeline through the second spray gun switching valve and the second spray gun isolation valve, which can also be integrated into the pulverized coal injection pipeline according to different furnace conditions, and injected into the molten reduction furnace through the pulverized coal spray gun, improving the flexibility of material supply.

[0013] Optionally, the mixed supply system includes two lime powder injection modules. The lime powder injection pipeline includes a lime powder pipeline shut-off valve and a spray gun isolation valve. The outlet of the lime powder injection device is connected to the lime powder pipeline shut-off valve. The lime powder pipeline shut-off valve of one of the lime powder injection modules is connected to the iron-containing material injection pipeline through a spray gun switching valve and a spray gun isolation valve. The lime powder pipeline shut-off valve of the other lime powder injection module is connected to the coal powder injection pipeline through a spray gun switching valve and a spray gun isolation valve.

[0014] Optionally, the spray gun anti-clogging device includes a protective nitrogen pipeline and a protective nitrogen valve group. The protective nitrogen valve group is connected to the spray pipeline through the protective nitrogen pipeline. The self-circulation pipeline is equipped with a self-circulation isolation valve and a hopper isolation valve. The outlet of the spray device is connected to the hopper in sequence through the self-circulation isolation valve and the hopper isolation valve.

[0015] To alleviate the aforementioned technical problems, this application also provides a method for distributing the supply of a molten reduction furnace.

[0016] This application provides a method for distributing the supply of a molten reduction furnace, which adopts the following technical solution: A method for distributing the supply of a molten reduction furnace, applied to the multi-material mixing supply system of the aforementioned molten reduction furnace, is characterized in that: the pulverized coal supply is divided into a first pulverized coal supply mode and a second pulverized coal supply mode according to the needs of two furnace conditions: production increase and carbon increase; the magnesium flux supply is divided into a premixing mode of iron-containing materials and magnesium flux and a separate injection mode of magnesium flux according to the needs of normal furnace conditions and abnormal furnace conditions.

[0017] Optionally, in the first pulverized coal supply mode, multiple pulverized coal injection pipelines are sequentially connected to two ferrous material injection pipelines. The pulverized coal is then injected into the molten reduction furnace via solid material injection guns. The method for connecting multiple pulverized coal injection pipelines to the ferrous material injection pipelines includes closing the self-circulation isolation valves of each pulverized coal injection system, opening the pipeline shut-off valves of each pulverized coal injection system, supplying nitrogen to the first pulverized coal injection system, and sequentially opening the first injection gun switching valve and the first injection gun isolation valve once the injection device pressure exceeds the set pressure value. After the injection nitrogen flow rate and pressure stabilize, pulverized coal supply is started, and the injection nitrogen flow rate is adjusted according to the supplied pulverized coal quantity. Similarly, the second pulverized coal injection system supplies nitrogen, and sequentially opening the second injection gun switching valve and the second injection gun isolation valve once the injection device pressure exceeds the set pressure value. The injection nitrogen flow rate stabilizes at the initial nitrogen flow rate set value. The protective nitrogen valve group for the pulverized coal injection lance is closed. Operation of the second pulverized coal injection pipeline and the ferrous material injection pipeline is then initiated. This includes opening the protective nitrogen valve group for the pulverized coal injection lance, the first injection lance switching valve, and the first injection lance isolation valve; closing the second injection lance switching valve and the second injection lance isolation valve; and, after the injection nitrogen flow rate and pressure stabilize, starting the pulverized coal supply. The set pressure value is 150±20 kPa, the initial nitrogen flow rate setting value is 1000±100 Nm³ / h, and the injection nitrogen flow rate for pulverized coal satisfies the formula F1=a1+b1*k1, where F1 is the injection nitrogen flow rate for pulverized coal (Nm³ / h), a1 is the basic nitrogen flow rate setting value (range 1050±50 Nm³ / h), k1 is the load coefficient (range 16±1 Nm³ / t), and b1 is the coal feed rate of the injection system (t / h).

[0018] Optionally, in the second pulverized coal supply mode, at least one pulverized coal injection pipeline is connected to the pulverized coal injection gun, and the remaining pulverized coal injection pipelines are incorporated into the iron-containing material injection pipeline, with the pulverized coal injection gun supplying 10t / h-20t / h of pulverized coal.

[0019] Optionally, in the premixing mode of the iron-containing material and the magnesium-containing flux, magnesium flux one is used, and magnesium flux one is selected from one or more of dolomite, magnesite, and light-burned dolomite; in the magnesium flux separate injection mode, magnesium flux two is used, and magnesium flux two can be selected from one or more of light-burned dolomite powder and steel slag. The main components of magnesium flux two are required to be MgO / Al2O3≥2%, CaO / SiO2≥1.5%, particle size≤3mm, and the magnesium flux separate injection rate is 0.5-20t / h.

[0020] In summary, this application includes at least one of the following beneficial technical effects: 1. By using four independent injection channels, precise decoupled control of iron charge, pulverized coal, calcium-containing flux, and magnesium-containing flux is achieved. By adding a magnesium-containing flux injection system, the flexibility and timeliness of slag magnesium-aluminum ratio adjustment under special furnace conditions are improved. This solves the problem of premixing iron-containing materials with dolomite in the existing process, which leads to a lag in slag magnesium-aluminum ratio adjustment under special furnace conditions and causes furnace condition deterioration. At the same time, pulverized coal and lime powder are injected separately through separate pipelines, which improves the activity of lime powder entering the furnace. This solves the problem of premixing hot pulverized coal and cold lime powder, which causes the moisture (about 2%) in the pulverized coal to react with the lime powder, affecting the activity of lime powder entering the furnace, and the problem of lime powder becoming damp and clumping, which easily blocks the pipeline. 2. By installing a self-circulating pipeline between the injection device and the silo, the self-circulation is activated during non-injection periods to maintain the activity of materials in the pipeline and prevent coal powder and flux from settling and solidifying; when low-flow injection is required, some materials are diverted to the self-circulating pipeline to maintain a stable gas-solid ratio in the main pipeline; when the injection module fails and stops, the self-circulating system can return all materials in the 30-meter conveying pipeline to the silo within 120 seconds. 3. The pulverized coal pipeline shut-off valve is connected to the iron-containing material injection pipeline and the pulverized coal injection gun through the first injection gun switching valve, the first injection gun isolation valve, the second injection gun switching valve, and the second injection gun isolation valve. Depending on the furnace conditions, pulverized coal can be directly injected into the melting reduction furnace through the pulverized coal injection gun for separate supply, or it can be integrated into the iron-containing material injection pipeline and injected into the melting reduction furnace through the solid material injection gun, thereby improving the flexibility of material supply. Attached Figure Description

[0021] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments of this application and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1This is a schematic diagram of the overall connection relationship in an embodiment of this application; Figure 2 This is a schematic diagram of the connection relationship of the delivery pipeline in the embodiments of this application.

[0022] Reference numerals: 100, Pulverized coal injection module; 110, Pulverized coal pipeline shut-off valve; 120, Pulverized coal spray gun; 200, Lime powder injection module; 210, Lime powder pipeline shut-off valve; 300, Iron-containing material injection module; 310, Iron-containing material pipeline shut-off valve; 320, Solid material spray gun; 400, Magnesium-containing flux injection module; 410, Magnesium-containing flux pipeline shut-off valve; 500, Injection device; 600, Injection pipeline; 610, First spray gun switching valve; 620, Second spray gun switching valve; 630, First spray gun isolation valve; 640, Second spray gun isolation valve; 700, Self-circulating pipeline; 710, Self-circulating isolation valve; 720, Silo isolation valve; 800, Spray gun anti-clogging device. Detailed Implementation

[0023] To more clearly illustrate the overall concept of this application, the following is in conjunction with the appendix. Figure 1-2 This application will be described in further detail.

[0024] Exemplary embodiments of this application are described below with reference to the accompanying drawings. It should be understood that these specific descriptions are for teaching those skilled in the art how to implement this application only, and are not intended to exhaustively describe all possible methods of this application, nor to limit the scope of this application.

[0025] The technical solution of this application and how it solves the above-mentioned technical problems will be described in detail below with specific embodiments. It should be noted that, unless otherwise specified, the following embodiments can be referenced, learned from, or combined with each other. The same terms, similar features, and similar implementation steps in different embodiments will not be described again.

[0026] This application discloses a multi-material mixing and feeding system for a molten reduction furnace. (Refer to...) Figure 1 A multi-material mixing and supply system for a molten reduction furnace includes multiple independent injection modules. These injection modules include a pulverized coal injection module 100, a lime powder injection module 200, an iron-containing material injection module 300, and a magnesium-containing flux injection module. The pulverized coal injection module 100 injects pulverized coal into the molten reduction furnace, the lime powder injection module 200 injects quicklime powder into the molten reduction furnace, the iron-containing material injection module 300 injects iron-containing materials into the molten reduction furnace, and the magnesium-containing flux injection module injects magnesium-containing flux into the molten reduction furnace.

[0027] By setting up four independent injection modules, precise decoupled control of iron charge, pulverized coal, calcium-containing flux, and magnesium-containing flux is achieved. The addition of a magnesium-containing flux injection system improves the flexibility and timeliness of slag magnesium-aluminum ratio adjustment under special furnace conditions, solving the problem of delayed slag condition deterioration caused by pre-mixing of iron-containing materials and dolomite in existing processes and resulting in delayed adjustment of the slag magnesium-aluminum ratio under special furnace conditions. Simultaneously, separate pipelines for pulverized coal and lime powder injection improve the activity of the lime powder entering the furnace, resolving the problem of moisture (approximately 2%) in the pulverized coal reacting with the lime powder after pre-mixing hot pulverized coal and cold lime powder, affecting the activity of the lime powder entering the furnace, and the problem of lime powder agglomerating and clogging pipelines due to moisture.

[0028] Reference Figure 1 The spraying module includes a spraying device 500, a conveying pipeline, and a spray gun anti-clogging device 800. The conveying pipeline includes a spraying pipe 600 and a self-circulating pipe 700. The inlet of the spraying device 500 is connected to the silo, and the outlet of the spraying device 500 is connected to the spraying pipe 600. The end of the spraying pipe 600 furthest from the spraying device 500 is connected to the spray gun, and the spray gun anti-clogging device 800 is connected to the spraying pipe 600 near the spray gun. The self-circulating pipe 700 is equipped with a self-circulating isolation valve 710 and a silo isolation valve 720. The outlet of the spraying device 500 is connected to the silo sequentially through the self-circulating isolation valve 710 and the silo isolation valve 720.

[0029] By setting up a self-circulating pipeline 700 between the injection device 500 and the silo, the self-circulation is activated during non-injection periods to circulate and inject the material in the injection device 500 into the silo, thus preventing coal powder and flux from depositing and adhering to the inner wall of the injection device 500. In the event of a malfunction or blockage of the injection pipeline, the self-circulating system can completely withdraw the material in the 30-meter conveying pipeline back to the silo within 120 seconds.

[0030] The spray gun anti-clogging device 800 includes a protective nitrogen pipeline and a protective nitrogen valve assembly. The protective nitrogen valve assembly is connected to the spray pipeline 600 through the protective nitrogen pipeline.

[0031] Reference Figure 1 and Figure 2 The mixed supply system includes 2-4 iron-containing material injection modules 300; in this embodiment, there are 2 iron-containing material injection modules 300. The iron-containing material injection pipeline 600 includes an iron-containing material pipeline shut-off valve 310 and a spray gun isolation valve. The outlet of the iron-containing material injection device 500 is connected to the iron-containing material pipeline shut-off valve 310, and the iron-containing material pipeline shut-off valve 310 is connected to the solid material spray gun 320 through the spray gun isolation valve.

[0032] Reference Figure 1 and Figure 2The mixed supply system includes 4-6 pulverized coal injection modules 100; in this embodiment, the number of pulverized coal injection modules 100 is 4. The pulverized coal injection pipeline 600 includes a pulverized coal pipeline shut-off valve 110, a spray gun switching valve, and a spray gun isolation valve. The spray gun switching valve includes a first spray gun switching valve 610 and a second spray gun switching valve 620, and the spray gun isolation valve includes a first spray gun isolation valve 630 and a second spray gun isolation valve 640. The outlet of the pulverized coal injection device 500 is connected to the pulverized coal pipeline shut-off valve 110, which is connected to the iron-containing material injection pipeline 600 in sequence through the first spray gun switching valve 610 and the first spray gun isolation valve 630; the pulverized coal pipeline shut-off valve 110 is connected to the pulverized coal spray gun 120 in sequence through the second spray gun switching valve 620 and the second spray gun isolation valve 640.

[0033] Depending on the furnace conditions, pulverized coal can be directly injected into the molten reduction furnace through the pulverized coal injection gun 120 for separate supply, or it can be integrated into the iron-containing material injection pipeline 600 and injected into the molten reduction furnace through the solid material injection gun 320, thereby improving the flexibility of material supply.

[0034] Reference Figure 1 and Figure 2 The mixed supply system includes 1-2 magnesium-containing flux injection modules 400; in this embodiment, there is one magnesium-containing flux injection module 400. The magnesium-containing flux injection pipeline 600 includes a magnesium-containing flux pipeline shut-off valve 410, a spray gun switching valve, and a spray gun isolation valve. The spray gun switching valve includes a first spray gun switching valve 610 and a second spray gun switching valve 620; the spray gun isolation valve includes a first spray gun isolation valve 630 and a second spray gun isolation valve 640. The outlet of the magnesium-containing flux injection device 500 is connected to the magnesium-containing flux pipeline shut-off valve 410. The magnesium-containing flux pipeline shut-off valve 410 is connected to the iron-containing material injection pipeline 600 sequentially through the first spray gun switching valve 610 and the first spray gun isolation valve 630; the magnesium-containing flux pipeline shut-off valve 410 is connected to the pulverized coal injection pipeline 600 sequentially through the second spray gun switching valve 620 and the second spray gun isolation valve 640.

[0035] The magnesium flux pipeline shut-off valve 410 is connected to the iron material injection pipeline 600 and the magnesium flux injection lance 420 through the first lance switching valve 610, the first lance isolation valve 630, the second lance switching valve 620, and the second lance isolation valve 640, respectively. Depending on the furnace conditions, the magnesium flux can be directly injected into the molten reduction furnace through the magnesium flux injection lance 420 for separate supply, or it can be premixed with the iron material injection pipeline 600 and injected into the molten reduction furnace through the solid material injection lance 320, thereby improving the flexibility of material supply.

[0036] Reference Figure 1 and Figure 2The mixed supply system includes two lime powder injection modules 200. The lime powder injection pipeline 600 includes a lime powder pipeline shut-off valve 210, a spray gun switching valve, and a spray gun isolation valve. The spray gun switching valve includes a first spray gun switching valve 610 and a second spray gun switching valve 620, and the spray gun isolation valve includes a first spray gun isolation valve 630 and a second spray gun isolation valve 640. The outlet of the lime powder injection device 500 is connected to the lime powder pipeline shut-off valve 210. The lime powder pipeline shut-off valve 210 of the lime powder injection module 200 is connected to the iron-containing material injection pipeline 600 sequentially through the first spray gun switching valve 610 and the first spray gun isolation valve 630; the lime powder pipeline shut-off valve 210 is connected to the coal powder injection pipeline 600 sequentially through the second spray gun switching valve 620 and the second spray gun isolation valve 640.

[0037] This application also discloses a method for distributing the supply of a molten reduction furnace, applied to the multi-material mixing supply system of the aforementioned molten reduction furnace. The pulverized coal supply is divided into a first pulverized coal supply mode and a second pulverized coal supply mode according to the needs of two furnace conditions: increased production and increased carbon content. The magnesium flux supply is divided into a premixing mode of iron-containing materials and magnesium flux, and a separate injection mode of magnesium flux, according to the needs of normal and abnormal furnace conditions.

[0038] The first pulverized coal supply mode connects multiple pulverized coal injection pipelines 600 to two iron-containing material injection pipelines 600 in sequence. The pulverized coal is then injected into the molten reduction furnace through the solid material injection gun 320. The method of connecting multiple pulverized coal injection pipelines 600 to the iron-containing material injection pipelines 600 includes closing the self-circulation isolation valves 710 of each pulverized coal injection system, opening the pipeline shut-off valves of each pulverized coal injection system, supplying nitrogen gas to the first pulverized coal injection system, and opening the first injection gun switching valve 610 and the first injection gun isolation valve 630 in sequence when the pressure of the injection device 500 is higher than the set pressure value. After the nitrogen gas flow rate and pressure stabilize, the pulverized coal supply is started, and the nitrogen gas flow rate is adjusted according to the amount of pulverized coal supplied.

[0039] The second pulverized coal injection system supplies nitrogen for injection. Once the pressure of the injection device 500 exceeds the set pressure value, the second spray gun switching valve 620 and the second spray gun isolation valve 640 are opened sequentially. After the injection nitrogen flow rate stabilizes at the initial nitrogen flow rate set value, the protective nitrogen valve group of the pulverized coal injection gun 120 is closed. Operation of the second pulverized coal injection pipeline 600 and the iron-containing material injection pipeline 600 is then performed, including opening the protective nitrogen valve group of the pulverized coal injection gun 120, the first spray gun switching valve 610, and the first spray gun isolation valve 630, and closing the second spray gun switching valve 620 and the second spray gun isolation valve 640. After the injection nitrogen flow rate and pressure stabilize, the pulverized coal supply is started. The method for merging other pulverized coal injection pipelines 600 into the two iron-containing material injection pipelines 600 is the same.

[0040] The pressure is set at 150±20 kPa, and the initial nitrogen flow rate is set at 1000±100 Nm³ / h. The nitrogen flow rate for pulverized coal injection satisfies the formula F1=a1+b1*k1, where F1 is the nitrogen flow rate for pulverized coal injection (Nm³ / h), a1 is the basic nitrogen flow rate setting (range 1050±50 Nm³ / h), k1 is the load factor (range 16±1 Nm³ / t), and b1 is the coal feed rate of the injection system (t / h). Assuming the current set coal feed rate of the pulverized coal injection system is 20 t / h, the nitrogen flow rate for pulverized coal injection is calculated as (1050±50)+20*(16±1), resulting in a nitrogen flow rate of 1300-1420 Nm³ / h.

[0041] The second pulverized coal supply mode connects at least one pulverized coal injection pipeline 600 to the pulverized coal injection gun 120, and the remaining pulverized coal injection pipelines 600 are incorporated into the iron-containing material injection pipeline 600. The pulverized coal injection gun 120 supplies 10t / h-20t / h of pulverized coal.

[0042] In the premixing mode of iron-containing materials and magnesium-containing flux, magnesium-containing flux one is used, which can be selected from one or more of dolomite, magnesite, and light-burned dolomite. In the separate injection mode of magnesium-containing flux, magnesium-containing flux two is used, which can be light-burned dolomite powder. The main components of magnesium-containing flux two are required to be MgO / Al2O3≥2%, CaO / SiO2≥1.5%, and particle size≤3mm. The injection rate of magnesium-containing flux alone is 0.5-20t / h.

[0043] The aforementioned abnormal furnace conditions include the stage during normal production when the ore injection volume needs to be reduced to maintain low ore injection volume due to equipment failure and maintenance, the stage of maintaining the mode of only injecting pulverized coal and not iron-containing materials, and the climbing stage of gradually increasing ore injection volume during the re-airing process.

[0044] The iron-containing material is supplied via a separate injection system, which employs 2-4 sets of iron-containing material injection devices 500 and iron-containing material conveying pipelines. The iron-containing material injection pipeline 600 is equipped with a pipeline shut-off valve and a spray gun isolation valve. The outlet of the iron-containing material injection device 500 connects to the injection pipeline 600, and the material is injected into the molten reduction furnace via the solid material spray gun 320 after passing through the pipeline shut-off valve and the spray gun isolation valve.

[0045] In the self-circulation mode, the valve of the injection pipeline 600 is closed. The injected material is connected to the self-circulation pipeline 700 through the outlet of the injection device 500, and then returns to the silo via the self-circulation isolation valve 710 and the silo isolation valve 720. The self-circulation mode of the injection system can realize online calibration of the feeding accuracy of the injection system and closed-loop emptying of the material in the injection system in the event of equipment failure.

[0046] For any parts not mentioned in this application, existing technologies may be used or referenced.

[0047] The above are all preferred embodiments of this application, and are not intended to limit the scope of protection of this application. Therefore, all equivalent changes made in accordance with the structure, shape and principle of this application should be covered within the scope of protection of this application.

Claims

1. A multi-material mixing and feeding system for a melting reduction furnace, characterized in that: The furnace includes multiple independent injection modules, including a pulverized coal injection module, a lime powder injection module, an iron-containing material injection module, and a magnesium-containing flux injection module. The pulverized coal injection module injects pulverized coal into the molten reduction furnace; the lime powder injection module injects quicklime powder into the molten reduction furnace; the iron-containing material injection module injects iron-containing materials into the molten reduction furnace; and the magnesium-containing flux injection module injects magnesium-containing flux into the molten reduction furnace. The iron-containing materials include iron ore powder and dolomite. The flux includes lightly calcined dolomite and / or steel slag. The lime powder injection module is used to inject calcium-containing solvent. The injection module includes an injection device, a conveying pipeline, and a spray gun anti-clogging device. The conveying pipeline includes an injection pipeline and a self-circulation pipeline. The inlet of the injection device is connected to the silo, and the outlet of the injection device is connected to the injection pipeline. The outlet of the injection device is connected to the silo through the self-circulation pipeline. The end of the injection pipeline away from the injection device is connected to the spray gun. The spray gun anti-clogging device is connected to the injection pipeline near the spray gun.

2. The multi-material mixing and feeding system for a melting reduction furnace according to claim 1, characterized in that: The mixed supply system includes 2-4 iron-containing material injection modules. The iron-containing material injection pipeline includes an iron-containing material pipeline shut-off valve and a spray gun isolation valve. The outlet of the iron-containing material injection device is connected to the iron-containing material pipeline shut-off valve. The iron-containing material pipeline shut-off valve is connected to the solid material spray gun through the spray gun isolation valve.

3. The multi-material mixing and feeding system for a melting reduction furnace according to claim 2, characterized in that: The mixed supply system includes 4-6 pulverized coal injection modules. The pulverized coal injection pipeline includes a pulverized coal pipeline shut-off valve, a spray gun switching valve, and a spray gun isolation valve. The spray gun switching valve includes a first spray gun switching valve and a second spray gun switching valve. The spray gun isolation valve includes a first spray gun isolation valve and a second spray gun isolation valve. The outlet of the pulverized coal injection device is connected to the pulverized coal pipeline shut-off valve. The pulverized coal pipeline shut-off valve is connected to the iron-containing material injection pipeline in sequence through the first spray gun switching valve and the first spray gun isolation valve. The pulverized coal pipeline shut-off valve is connected to the pulverized coal spray gun in sequence through the second spray gun switching valve and the second spray gun isolation valve.

4. The multi-material mixing and feeding system for a melting reduction furnace according to claim 3, characterized in that: The mixed supply system includes 1-2 magnesium flux injection modules. The magnesium flux injection pipeline includes a magnesium flux pipeline shut-off valve, a spray gun switching valve, and a spray gun isolation valve. The outlet of the magnesium flux injection device is connected to the magnesium flux pipeline shut-off valve. The magnesium flux pipeline shut-off valve is connected to the iron-containing material injection pipeline in sequence through the first spray gun switching valve and the first spray gun isolation valve. The magnesium flux pipeline shut-off valve is connected to the pulverized coal injection pipeline in sequence through the second spray gun switching valve and the second spray gun isolation valve.

5. The multi-material mixing and feeding system for a melting reduction furnace according to claim 3, characterized in that: The mixed supply system includes two lime powder injection modules. The lime powder injection pipeline includes a lime powder pipeline shut-off valve and a spray gun isolation valve. The outlet of the lime powder injection device is connected to the lime powder pipeline shut-off valve. The lime powder pipeline shut-off valve of one of the lime powder injection modules is connected to the iron-containing material injection pipeline through a spray gun switching valve and a spray gun isolation valve. The lime powder pipeline shut-off valve of the other lime powder injection module is connected to the coal powder injection pipeline through a spray gun switching valve and a spray gun isolation valve.

6. The multi-material mixing and feeding system for a melting reduction furnace according to claim 1, characterized in that: The spray gun anti-clogging device includes a protective nitrogen pipeline and a protective nitrogen valve group. The protective nitrogen valve group is connected to the spray pipeline through the protective nitrogen pipeline. The self-circulation pipeline is equipped with a self-circulation isolation valve and a hopper isolation valve. The outlet of the spray device is connected to the hopper in sequence through the self-circulation isolation valve and the hopper isolation valve.

7. A method for distributing the supply of materials in a molten reduction furnace, applied to a multi-material mixing and supply system for a molten reduction furnace as described in claims 1-6, characterized in that: The coal powder supply is divided into two modes according to the needs of two furnace conditions: production increase and carbon increase. The magnesium flux supply is divided into two modes according to the needs of normal furnace conditions and abnormal furnace conditions: the premixing mode of iron-containing materials and magnesium flux and the separate injection mode of magnesium flux.

8. The method for distributing the supply of a molten reduction furnace according to claim 7, characterized in that: The first pulverized coal supply mode sequentially connects multiple pulverized coal injection pipelines into two ferrous material injection pipelines, injecting the pulverized coal into the melting reduction furnace via solid material injection guns. The method for connecting multiple pulverized coal injection pipelines into the ferrous material injection pipelines includes closing the self-circulation isolation valves of each pulverized coal injection system, opening the pipeline shut-off valves of each pulverized coal injection system, supplying nitrogen to the first pulverized coal injection system, and sequentially opening the first injection gun switching valve and the first injection gun isolation valve after the injection nitrogen flow rate and pressure stabilize. Then, pulverized coal supply is initiated, with the injection nitrogen flow rate adjusted according to the pulverized coal supply quantity. The second pulverized coal injection system supplies nitrogen, and sequentially opening the second injection gun switching valve and the second injection gun isolation valve after the injection device pressure exceeds the set pressure. Once the injection nitrogen flow rate stabilizes at the initial nitrogen flow rate setting value, the pulverized coal... The nitrogen valve group for the spray gun protection is closed. Operation of the second pulverized coal injection pipeline and the ferrous material injection pipeline is then initiated. This includes opening the nitrogen valve group for the pulverized coal spray gun protection, the first spray gun switching valve, and the first spray gun isolation valve; closing the second spray gun switching valve and the second spray gun isolation valve; and, after the nitrogen flow rate and pressure stabilize, starting the pulverized coal supply. The set pressure value is 150±20 kPa, the initial nitrogen flow rate setting value is 1000±100 Nm³ / h, and the pulverized coal nitrogen flow rate satisfies the formula F1=a1+b1*k1, where F1 is the pulverized coal nitrogen flow rate in Nm³ / h, a1 is the basic nitrogen flow rate setting value with a range of 1050±50 Nm³ / h, k1 is the load coefficient with a range of 16±1 Nm³ / t, and b1 is the coal feed rate of the injection system in t / h.

9. The method for distributing the supply of a molten reduction furnace according to claim 8, characterized in that: The second pulverized coal supply mode connects at least one pulverized coal injection pipeline to the pulverized coal injection gun, and the remaining pulverized coal injection pipelines are integrated into the iron-containing material injection pipeline. The pulverized coal supply quantity of the pulverized coal injection gun is 10t / h-20t / h.

10. The method for distributing the supply of a molten reduction furnace according to claim 8, characterized in that: In the premixing mode of iron-containing materials and magnesium-containing flux, magnesium-containing flux one is used, which is selected from one or more of dolomite, magnesite, and light-burned dolomite; in the separate injection mode of magnesium-containing flux, magnesium-containing flux two is used, which can be selected from one or more of light-burned dolomite powder and steel slag. The main components of magnesium-containing flux two are required to be MgO / Al2O3≥2%, CaO / SiO2≥1.5%, particle size≤3mm, and the separate injection rate of magnesium-containing flux is 0.5-20t / h.

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