Metallurgical process for producing high quality steel or pure iron in a static one-step process

Abstract

The application discloses a metallurgical method for producing high-quality steel or pure iron through a static one-step method, and relates to the technical field of metallurgy. The one-step short process from ore powder to molten iron avoids the repeated heating process of the traditional process, and heat loss is extremely small. The static product has high quality. The furnace charge is always in a static state during the process of heating reduction to high-temperature melting. The purification and separation time is sufficient in the high-temperature melting state, the molten slag is separated completely, and the gas phase overflows completely.

Description

Technical Field

[0001] This invention relates to the field of metallurgical technology, and in particular to a static one-step metallurgical method for producing high-quality steel or pure iron. Background Technology

[0002] The traditional iron ore powder metallurgical process is as follows: iron ore powder is mixed with a reducing agent and sintered in a sintering furnace. The sintered material, along with slag-forming solvent and coke, is smelted in a blast furnace to obtain blast furnace iron. The blast furnace iron is then decarburized and smelted in an electric furnace, and then refined in an electric furnace once or multiple times to obtain high-quality steel. The aforementioned process has several drawbacks: First, the furnace charge needs to be heated from room temperature to the melting temperature multiple times, consuming energy from repeated heating and resulting in significant heat loss. Second, traditional metallurgical processes involve various metallurgical equipment, such as sintering furnaces, blast furnaces, electric arc furnaces, and induction furnaces, which involve large investments, large floor space requirements, and high costs for molten iron transportation and operation management. Third, during the entire process, the furnace charge is subject to secondary pollution due to direct contact with pulverized coal, coke, electrodes, air, and dust, leading to an increase in carbon, phosphorus, sulfur, and harmful elements, thus increasing refining difficulty and costs. Fourth, traditional metallurgical processes are conducted in a dynamic state, with the molten iron constantly tumbling, flowing, and rotating under the impact of external forces (blowing force, electric arc thrust, electromagnetic stirring force). Each melting process is always in a dynamic state, which is not conducive to the separation of slag and gas. Summary of the Invention

[0003] To solve the above-mentioned technical problems, the present invention provides a metallurgical method for producing high-quality steel or pure iron in a static one-step process, and uses a simple microwave and heating element composite electric furnace to produce high-quality steel or pure iron.

[0004] To achieve this technical objective, the present invention adopts the following solution: A static one-step metallurgical method for producing high-quality steel or pure iron includes the following steps: Iron concentrate is used as raw material, with auxiliary materials added, mixed evenly, granulated and dried to obtain furnace charge; The furnace charge is loaded into a crucible in one go and sent into a composite electric furnace for heating. The furnace charge undergoes reduction, melting and purification processes in the furnace to directly obtain high-quality steel or pure iron.

[0005] Furthermore, the auxiliary materials include any one or more of the following: reducing agent, slag-forming agent, alloy powder, and binder.

[0006] Furthermore, the composite electric furnace is a metallurgical furnace that integrates microwave heating and electric heating.

[0007] Furthermore, the composite electric furnace includes a fixed furnace body, a movable furnace cover, a movable furnace bottom, a crucible, a microwave generator, an electric heating element, and a heat insulation layer. The upper and lower ends of the fixed furnace body are connected to the movable furnace cover and the movable furnace bottom respectively to form the entire furnace body. Several microwave generators are arranged from top to bottom on the outer side of the furnace body. The inner wall of the furnace body is fixed with a heat insulation layer. An electric heating element is set in the furnace cavity inside the heat insulation layer. The crucible is placed on the movable furnace bottom.

[0008] Furthermore, the movable furnace cover is equipped with a detection port and an exhaust port, the detection port being used to install pressure sensors, temperature sensors and / or gas sensors.

[0009] Furthermore, the heating element can be any one of the following shapes: ring-shaped, spiral-shaped, rectangular, rod-shaped, tubular, or irregular; the heating element material is a high-temperature resistant conductive material.

[0010] Furthermore, it also includes a lateral moving vehicle, with a lifting column connected to the bottom of the movable furnace bottom, and the lifting column is connected to the lateral moving vehicle.

[0011] Furthermore, the steps of charging the furnace charge into the furnace for smelting include: Loading the furnace: Fill the crucible with the dried furnace charge, place the crucible filled with furnace charge on the movable furnace bottom, move the lateral moving car to directly under the fixed furnace body, use the lifting column to raise the movable furnace bottom and seal it with the fixed furnace body, install the temperature, pressure and gas detection sensors in the corresponding detection ports, cover the movable furnace cover and seal it with the fixed furnace body. Microwave heating: According to the predetermined power requirements, the microwave generator starts working until the furnace temperature rises to above 1100℃, then the microwave power is reduced. This heating time is between 2 and 3 hours. Electric heating: When the furnace temperature rises to 1100℃, turn on the electric heating element. When the furnace temperature exceeds 1300℃, turn off all microwave generators, and the electric heating element continues to heat, so that the furnace temperature continues to rise. Melting stage: The heating element raises the furnace temperature to between 1500℃ and 2800℃, melting the furnace charge; Constant temperature purification stage: After reaching the melting temperature, the heating power of the electric heating element is gradually (stepwise or linearly) reduced to keep the furnace temperature constant at the set temperature and maintain the temperature. Unloading: After the heat preservation is completed, the movable furnace bottom is lowered to the unloading height, and then moved to a position outside the fixed furnace body where the crucible can be safely hoisted by a horizontal moving cart to complete the unloading and obtain the final product.

[0012] Furthermore, the furnace charge remains in the same furnace chamber and is in a static state throughout the entire process. That is, there is no external macroscopic force or forced stirring. It relies entirely on natural diffusion due to thermodynamic equilibrium, natural gravity floating and settling, and natural selection within the solid solution phase to achieve the purpose of gas phase and slag liquid aggregation and separation, thereby obtaining high-quality steel or molten iron.

[0013] Furthermore, the entire furnace cavity is in a closed state, and the furnace cavity is in a positive pressure, negative pressure, vacuum, inert gas or reducing gas atmosphere throughout or in stages.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: (1) The one-step production process has low energy consumption. The process from ore powder to molten iron is a short one-step process, which avoids the repeated heating process of traditional processes and minimizes heat loss. (2) High static production quality. During the process of heating and reducing the furnace charge to high temperature melting, it is always in a static state. The purification and separation time is sufficient under high temperature melting state, the slag is completely separated and the gas phase is completely overflowed. (3) The clean production process is accurate, there is no secondary pollution of the furnace charge during the process, and the final composition of the molten iron is easy to control; (4) Closed production with low pollution: the entire furnace cavity is in a closed state, and based on the static (clean) production process, environmental pollution is greatly reduced and carbon emissions are reduced. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the structure of the composite electric furnace provided by the present invention; The following are marked in the diagram: 1. Movable furnace lid; 2. Inspection port; 3. Exhaust vent; 4. Insulation layer; 5. Heating element power supply; 6. Heating element; 7. Crucible; 8. Movable furnace bottom; 9. Fixed furnace body; 10. Microwave generator; 11. Microwave power supply; 12. Controller; 13. Furnace charge; 14. Horizontal track; 15. Lifting column; 16. Horizontal moving trolley. Detailed Implementation

[0016] To fully understand the purpose, features and effects of the present invention, the present invention will be described in detail through the following specific embodiments, but the present invention is not limited thereto.

[0017] like Figure 1 As shown, the present invention provides a static one-step metallurgical method for producing high-quality steel or pure iron, which is realized by using a microwave and heating element composite electric furnace.

[0018] The composite electric furnace includes a fixed furnace body 9, a movable furnace cover 1, a movable furnace bottom 8, a crucible 7, a microwave generator 10, a heating element 6, and an insulation layer 4. Several microwave generators 10 are arranged from top to bottom on the outer side of the fixed furnace body 9. The insulation layer 4 is adhered to the inner side of the fixed furnace body 9. The heating element 6 is installed in the furnace cavity inside the insulation layer 4, and the crucible 7 is located inside the heating element 6, containing furnace charge 13. The movable furnace cover 1 is installed at the upper end of the fixed furnace body 9, sealing the furnace cavity. Several detection ports 2 and exhaust ports 3 are provided on the movable furnace cover 1. Different detection ports 2 are equipped with temperature sensors, pressure sensors, or gas sensors, and the exhaust ports 3 are equipped with valves. The bottom of the fixed furnace body 9 is connected to the movable furnace bottom 8. The movable furnace bottom 8 consists of a furnace shell and an insulation layer from the outside to the inside. The crucible 7 is placed on the movable furnace bottom 8 for easy loading and unloading of materials. A lifting column 15 is connected to the lower side of the movable furnace bottom 8. The lifting column 15 drives the movable furnace bottom 8 to move up and down. The lifting column 15 is installed at the corner of the transverse moving carriage 16. The transverse moving carriage 16 is equipped with a driving force, such as a motor reducer and a battery. The carriage that enables transverse movement is existing technology and will not be described in detail. The transverse moving carriage 16 travels on the transverse track 14, which can be in the form of train tracks and train wheels. It also has a positioning and locking structure to lock in place during the smelting process, preventing even slight displacement from disrupting the static conditions.

[0019] It should be noted that a high-temperature resistant flexible sealing ring is installed between the movable furnace cover 1, the movable furnace bottom 8, and the fixed furnace body 9 to achieve vacuum / atmosphere sealing. The heating element can be annular, spiral, rectangular, rod-shaped, tubular, or irregularly shaped; its material can be high-temperature resistant conductive materials such as tungsten, molybdenum, tantalum, niobium, graphite, silicon carbide, and molybdenum disilicide, and the material is selected according to the actual situation.

[0020] The microwave generator 10 is electrically connected to the microwave power supply 11, and the microwave power supply 11 is communicatively connected to the controller 12. The controller 12 is also communicatively connected to the temperature sensor, pressure sensor, gas sensor, exhaust valve, and heating element power supply 5. The heating element power supply 5 is electrically connected to the heating element 6 to supply power to it.

[0021] The exhaust vent is connected to a dust removal system via a pipe to treat the flue gas. Simultaneously, the exhaust vent is also connected to a vacuum pump and other gas charging devices via pipes to alter the atmosphere inside the furnace. The vacuum pump and other gas charging devices are existing technologies and can be purchased and installed from commercially available sources to meet this functional requirement.

[0022] A static one-step metallurgical method for producing high-quality steel or pure iron includes the following steps: S1. Preparation of furnace charge: Iron concentrate (TFe content above 66%) is used as raw material, combined with reducing agent, slag-forming agent, alloy powder, binder, etc. The selection of auxiliary materials is determined according to the target product. After uniform mixing, it is granulated and dried to obtain the furnace charge to be treated.

[0023] S2. Loading the furnace. Fill the crucible with the dried furnace charge particles, place the crucible full of furnace charge on the movable furnace bottom, move the lateral moving car to directly under the fixed furnace body so that the movable furnace bottom rises and seals with the fixed furnace body 9, install the temperature, pressure and gas detection sensors in the corresponding detection ports 2, and cover the movable furnace cover 1 and seal it with the fixed furnace body 9.

[0024] S3. Microwave Heating. Power is supplied to the corresponding microwave power source according to the predetermined power requirements, causing the microwave generator to start working until the furnace temperature reaches above 1100℃. At this point, the microwave power is appropriately reduced (this can be achieved by partially shutting down the microwave generator to lower the total microwave power). This heating phase typically takes between 2 and 3 hours.

[0025] S4. Electric Heating. When the furnace temperature reaches 1100°C, power is supplied to the heating element, and microwaves and the heating element heat simultaneously. When the furnace temperature exceeds 1300°C, the microwave power supply 11 is completely turned off, and power is supplied to the heating element 6 to allow the furnace temperature to continue rising. The temperature rise time from 1100°C to 1300°C is generally around 30 minutes.

[0026] S5, Melting Stage. Continuously supply power to the heating element 6 to raise the furnace temperature to between 1500℃ and 1650℃. This heating stage generally takes about 10 minutes.

[0027] S6. Constant Temperature Purification Stage. After reaching the melting temperature, reduce the power output of heating element 6 (this can be a linear reduction or a step-wise reduction) to keep the furnace temperature constant at around 1600°C for approximately 30 minutes. During the electric heating stage, the gas inside the furnace charge is gradually discharged. During the purification stage, the furnace charge is completely melted in the crucible without boiling or churning.

[0028] S7. Unloading. Lower the movable furnace bottom 8 to the unloading height, and move the transverse moving cart 16 laterally to a position outside the fixed furnace body 9 where the crucible 7 can be safely hoisted. This completes the unloading operation.

[0029] This invention is a static one-step method.

[0030] One-step method: From loading to melting and unloading, the furnace charge remains in the same furnace cavity. Iron concentrate is used as raw material, along with reducing agent, slag-forming agent, alloy powder, etc. After being mixed evenly, it is granulated and dried (natural drying is also possible). The dried furnace charge is then loaded into a composite electric furnace at once and heated by electricity. The furnace charge undergoes reduction, melting, and purification processes in the furnace to directly obtain high-quality steel or pure iron.

[0031] Static: Heating, reduction, melting, and purification occur under static conditions. There are no external macroscopic forces (electric arc thrust, air supply thrust, etc.) or forced stirring. It relies entirely on thermodynamic equilibrium, natural diffusion, natural gravity settling, and natural selection of solid and solution phases to achieve the purpose of gas phase and slag-liquid aggregation and separation.

[0032] The absence of external macroscopic forces mentioned here excludes the internal natural movements caused by the thermal diffusion of the furnace charge itself, gas buoyancy, and gravity settling; it refers only to the absence of external active forces such as blasting, electromagnetic stirring, electric arc impact, and mechanical agitation.

[0033] Clean state: After the furnace charge enters the furnace, it does not come into contact with coke, electrodes, air or dust, and there is no secondary pollution throughout the entire process.

[0034] Enclosed: The entire furnace cavity is in a closed state, and the furnace cavity is in a positive pressure, negative pressure, vacuum, inert gas or reducing gas atmosphere throughout or in stages. Example 1

[0035] The raw materials are: iron concentrate (TFe content 66%): semi-coke powder (grade 1): 60% chromium ferrophosphate powder (chromium mass fraction ≥ 60%): 75% manganese ferrophosphate powder (manganese mass content 75%): 75% ferrosilicon powder (silicon mass content 72%~80%) = 1.722:0.8:0.015:0.096:0.042. The proportions of the raw materials are determined based on the various components and their content requirements in the final target product.

[0036] Mix the above furnace charge evenly according to the ratio and add an appropriate binder (using a binder commonly used in chromium alloy steel furnace charge) to granulate, and use after natural drying for 24 hours.

[0037] The above-mentioned metallurgical method is used to feed the furnace charge into a composite electric furnace for smelting. The holding time during the constant temperature purification stage is no less than 20 minutes. Finally, 20Cr low-carbon alloy steel liquid is obtained. The upper layer of the crucible is a thin slag layer, and the lower layer is the product. The thin slag layer is formed by impurities after the furnace charge purification, and this layer serves to insulate the product from oxygen. Example 2

[0038] The raw materials are iron concentrate (TFe content 66%): aluminum powder (mass fraction 99.7%): fluorite = 2.165: 0.5: 0.005. The above furnace materials are mixed evenly in proportion and granulated with appropriate binder. After natural drying for 24 hours, they are used.

[0039] The above metallurgical method involves feeding the furnace charge into a composite electric furnace for smelting, maintaining a constant furnace temperature of 1650℃ for at least 30 minutes. The molten iron can be tapped by removing the crucible, pouring it into a condenser, or allowing it to solidify slowly within the crucible at the desired furnace temperature before tapping. Following these steps yields high-purity iron of grade 4N or higher. Higher purity furnace charge results in a better quality final product.

[0040] Finally, it should be noted that the above-listed embodiments are merely preferred embodiments of the present invention. Of course, those skilled in the art can make modifications and variations to the present invention. If such modifications and variations fall within the scope of the claims of the present invention and their equivalents, they should be considered as being within the protection scope of the present invention.

Claims

1. A static one-step metallurgical method for producing high-quality steel or pure iron, characterized in that, Includes the following steps: Iron concentrate is used as raw material, with auxiliary materials added, mixed evenly, granulated and dried to obtain furnace charge; The furnace charge is loaded into a crucible in one go and sent into a composite electric furnace for heating. The furnace charge undergoes reduction, melting and purification processes in the furnace to directly obtain high-quality steel or pure iron.

2. The metallurgical method for producing high-quality steel or pure iron in a static one-step process according to claim 1, characterized in that, The auxiliary materials include any one or more of the following: reducing agent, slag-forming agent, alloy powder, and binder.

3. The static one-step metallurgical method for producing high-quality steel or pure iron according to claim 1, characterized in that, The composite electric furnace is a metallurgical furnace that combines microwave heating and electric heating.

4. The static one-step metallurgical method for producing high-quality steel or pure iron according to claim 3, characterized in that, The composite electric furnace includes a fixed furnace body, a movable furnace cover, a movable furnace bottom, a crucible, a microwave generator, an electric heating element, and an insulation layer. The upper and lower ends of the fixed furnace body are connected to the movable furnace cover and the movable furnace bottom to form the entire furnace body. Several microwave generators are arranged from top to bottom on the outside of the furnace body. An insulation layer is fixed on the inner wall of the furnace body. An electric heating element is installed in the furnace cavity inside the insulation layer. A crucible is placed inside the electric heating element and placed on the movable furnace bottom.

5. The static one-step metallurgical method for producing high-quality steel or pure iron according to claim 4, characterized in that, The movable furnace cover is equipped with a detection port and an exhaust port. The detection port is used to install pressure sensors, temperature sensors and / or gas sensors.

6. The static one-step metallurgical method for producing high-quality steel or pure iron according to claim 4, characterized in that, The heating element can be any shape, such as ring, spiral, rectangular, rod, tubular, or irregular; the heating element material is a high-temperature resistant and conductive material.

7. The static one-step metallurgical method for producing high-quality steel or pure iron according to claim 4, characterized in that, It also includes a lateral moving car, with a lifting column connected to the bottom of the movable furnace bottom, and the lifting column is connected to the lateral moving car.

8. The static one-step metallurgical method for producing high-quality steel or pure iron according to claim 4, characterized in that, The steps for charging the furnace charge into the furnace for smelting include: Loading the furnace: Fill the crucible with the dried furnace charge, place the crucible filled with furnace charge on the movable furnace bottom, move the lateral moving car to directly under the fixed furnace body, use the lifting column to raise the movable furnace bottom and seal it with the fixed furnace body, install the temperature, pressure and gas detection sensors in the corresponding detection ports, cover the movable furnace cover and seal it with the fixed furnace body. Microwave heating: According to the predetermined power requirements, the microwave generator starts working until the furnace temperature rises to above 1100℃, then the microwave power is reduced. This heating time is between 2 and 3 hours. Electric heating: When the furnace temperature rises to 1100℃, turn on the electric heating element. When the furnace temperature exceeds 1300℃, turn off all microwave generators, and the electric heating element continues to heat, so that the furnace temperature continues to rise. Melting stage: The heating element raises the furnace temperature to between 1500℃ and 2800℃, melting the furnace charge; Constant temperature purification stage: After reaching the melting temperature, the heating power of the electric heating element is reduced in a stepwise or linear manner to keep the furnace temperature constant at the preset temperature and perform heat preservation treatment. Unloading: After the heat preservation is completed, the movable furnace bottom is lowered to the unloading height, and then moved to a position outside the fixed furnace body where the crucible can be safely hoisted by a horizontal moving cart to complete the unloading and obtain the final product.

9. The metallurgical method for producing high-quality steel or pure iron in a static one-step process according to claim 1, characterized in that, The furnace charge remains in the same furnace chamber and is in a static state throughout the entire process. That is, there is no external macroscopic force or forced stirring. It relies entirely on natural diffusion due to thermodynamic equilibrium, natural gravity floating and settling, and natural selection within the solid solution phase to achieve the purpose of gas phase and slag liquid aggregation and separation, thereby obtaining high-quality steel or molten iron.

10. The metallurgical method for producing high-quality steel or pure iron in a static one-step process according to claim 1, characterized in that, The entire furnace cavity is in a closed state, and the furnace cavity is in a positive pressure, negative pressure, vacuum, inert gas or reducing gas atmosphere throughout or in stages.

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