CN109777913B - Method and device for directly making steel using high-temperature electric furnace flue gas and iron concentrate powder - Google Patents

Abstract

The invention discloses a method and a device for directly steelmaking by adding iron concentrate powder into high-temperature flue gas of an electric furnace, wherein more than 30% of steel is left in the steelmaking smelting electric furnace, a charging reaction tunnel is arranged and connected to the electric furnace, and the flue gas is led out from the electric furnace; concentrate pellets containing iron concentrate powder and carbon are conveyed to the electric furnace in a reverse direction relative to flue gas in a feed reaction tunnel, and the concentrate pellets are heated by the electric furnace flue gas so that part of iron elements are reduced by the concentrate pellets and enter an electric furnace molten pool through the feed reaction tunnel. The invention utilizes the waste heat of the high-temperature flue gas of the electric furnace to realize direct steelmaking of part of the iron concentrate powder, reduces the blast furnace links, reduces the emission, reduces the cost price of steelmaking raw materials and improves the market competitiveness of short flow. The addition of the iron concentrate powder dilutes harmful elements in the scrap steel, and is beneficial to improving the component quality of molten steel. The need and dependence of scrap steel is reduced.

Description

Method and device for directly making steel using high-temperature electric furnace flue gas and iron concentrate powder

Technical field

The invention belongs to the field of metallurgical technology, and particularly relates to a method and device for directly making steel by adding iron concentrate powder to high-temperature flue gas of an electric furnace.

Background technique

Electric arc furnace short-process steelmaking is a steelmaking technology that uses scrap steel as the main raw material. It has the advantages of lower energy consumption and less CO2 emissions, and occupies an important position in steelmaking production. However, for a long time, the high price of scrap steel resources has caused the cost of electric furnace steelmaking to be higher than that of the blast furnace-converter long process, and the market competition is not strong; due to the difficulty in controlling the content of harmful elements in scrap steel resources, it affects the composition and quality of steel; scrap steel resources are in short supply, and electric arc furnaces are short-term. The process relies heavily on scrap steel.

Contents of the invention

In view of the above-mentioned shortcomings of the prior art, the object of the present invention is to provide a method for directly making steel by adding iron concentrate powder to high-temperature flue gas of an electric furnace, adding iron concentrate powder and scrap steel to directly make steel, effectively reducing production costs. .

In order to achieve the above objects and other related objects, the technical solutions of the present invention are as follows:

A method of directly making steel by adding iron concentrate powder to the high-temperature flue gas of an electric furnace. The steel-making and smelting electric furnace retains more than 30% of the steel, and a feeding reaction tunnel is set up to connect to the electric furnace to lead the flue gas out of the electric furnace; The powder and carbon concentrate briquettes are transported to the electric furnace in the opposite direction to the flue gas in the feeding reaction tunnel. The electric furnace flue gas heats the concentrate briquettes, causing the concentrate briquettes to reduce part of the iron elements and enter the electric furnace through the feeding reaction tunnel. molten pool.

Using the above method, the waste heat of the high-temperature flue gas of the electric furnace is used to realize direct steelmaking with part of the iron concentrate powder. This part of the iron concentrate powder reduces the blast furnace link, reduces emissions, lowers the cost and price of steelmaking raw materials, and improves the short-process market competitiveness. The addition of iron concentrate powder dilutes harmful elements in scrap steel, which is beneficial to improving the composition quality of molten steel. Reduced scrap demand and dependence.

Optionally, an oxygen lance is set up in the electric furnace to blow oxygen to the blanking point of the electric furnace molten pool to enhance the carbon-oxygen reaction in the molten pool.

Optionally, the concentrate pressure balls are laid on the surface of the scrap steel material layer in the feeding reaction tunnel, and the concentrate pressure balls undergo ferrite reduction reaction

Optionally, the concentrate briquettes enter the electric furnace in the form of a combination of reduced iron, residual mineral powder, and residual carbon after the reaction; or, the concentrate briquettes are laid on the surface of the scrap steel layer in the feeding reaction tunnel, and the concentrate A ferrite reduction reaction occurs during the briquetting process. After the briquetting reaction, the concentrate enters the electric furnace together with scrap steel in the combined form of reduced iron, residual ore powder, and residual carbon.

Optionally, a burner or nozzle is installed on the feeding reaction tunnel, and the burner or nozzle gas and electric furnace flue gas combine to heat the concentrate briquettes.

Optionally, increase the carbon content in the concentrate briquettes or add combustibles, provide air or oxygen through a burner or nozzle, burn the carbon or combustibles in the concentrate briquettes in the feed reaction tunnel, and provide necessary reaction heat. Reduce gas consumption of burners or nozzles.

Optionally, the bottom of the feed reaction tunnel is arranged in a stepped shape that decreases along the feeding direction. The concentrate press balls are disturbed and rolled by the steps when being transported in the feed reaction tunnel, thereby improving the heating uniformity of the concentrate press balls.

Optionally, distribution is carried out through a concentrate press ball distribution device, and at least one dust removal port is provided on the feeding reaction tunnel to introduce the electric furnace flue gas into the concentrate press ball distribution device to preheat the concentrate press balls. The preheated concentrate The pressure ball is sent into the feeding reaction tunnel through the discharge pipe, and is guided to the electric furnace by the feeding reaction tunnel.

Optionally, the flue gas discharged from the dust removal port penetrates the gap between the concentrate press balls in the concentrate press ball distribution device, performs penetrating preheating of the concentrate press balls, and controls the concentrate press ball distribution device. Mine pressure ball feeding speed, preheating time and preheating temperature.

Optionally, the concentrate press ball distribution device is provided with a preheating chamber. The top of the preheating chamber is connected to a high-level silo. The bottom of the preheating chamber is connected to a vibrating feeding device. The flue gas inlet pipe of the preheating chamber is connected to the high-level silo. The dust removal port is connected, and the preheating chamber is connected with a flue gas outlet pipe.

Optionally, the preheating chamber is in the form of a V-shaped, U-shaped, Y-shaped or L-shaped container, or the preheating chamber and the vibrating feeding device form a V-shaped, U-shaped, Y-shaped or L-shaped container; The flue gas outlet pipe of the hot room is connected with an air mixing regulating device.

Optionally, a concentrate press ball distribution device is provided at at least one position of the feeding reaction tunnel to connect with the feeding reaction tunnel for distribution. There is a dynamic sealing device at the end of the feeding reaction tunnel, and there is an open scrap steel feeding section behind the dynamic sealing device.

Optionally, the feeding reaction tunnel is arranged horizontally or tilted, and at least one dust removal port is provided on the feeding reaction tunnel. When more than two dust removal ports are provided on the feeding reaction tunnel, each dust removal port is provided with an independent or linked dust removal port. Smoke regulating device.

The invention also provides a device for directly making steel by adding iron concentrate powder to high-temperature flue gas of an electric furnace, which includes an electric furnace and a feeding reaction tunnel that is hermetically connected to the electric furnace. It also includes scrap steel feeding equipment and a concentrate ball press distribution device. The scrap steel The feeding equipment and the concentrate briquette distribution device are used to distribute the scrap steel and concentrate briquettes to the feeding reaction tunnel. The feeding reaction tunnel is used to lead the flue gas out of the electric furnace and transport the scrap steel and concentrate briquettes to the electric furnace.

Optionally, there is a dynamic sealing device at the end of the feeding reaction tunnel, and there is an open scrap steel feeding section behind the dynamic sealing device, and the scrap steel feeding equipment is arranged corresponding to the scrap steel feeding section.

Optionally, a concentrate press ball distribution device is provided at the front of the scrap steel feeding section and/or a concentrate press ball distribution device is provided on the feeding reaction tunnel before the dynamic sealing device.

Optionally, the feeding reaction tunnel is provided with a dust removal port, which is connected to the concentrate press ball distribution device through the flue gas inlet pipe, and is used to introduce the electric furnace flue gas into the concentrate press ball distribution device to concentrate the concentrate. The ore press balls are preheated. The concentrate press ball distribution device is connected to the feeding reaction tunnel through the discharge pipe and is used to send the preheated concentrate press balls to the feeding reaction tunnel.

Optionally, the discharge pipe is connected to the tail or middle and rear section of the feeding reaction tunnel.

Optionally, the concentrate press ball distribution device is provided with a preheating chamber, the top of the preheating chamber is connected to a high-level silo, the bottom of the preheating chamber is connected to a vibrating feeding device, and the flue gas inlet pipe is connected to the preheating chamber. room, and the preheating room is connected to a flue gas outlet pipe.

Optionally, the preheating chamber is a V-shaped, U-shaped, Y-shaped or L-shaped container, or the preheating chamber and the vibrating feeding device form a V-shaped, U-shaped, Y-shaped or L-shaped container.

Optionally, the flue gas outlet pipe of the preheating chamber is connected to a mixed air regulating device.

Optionally, the outlet of the preheating chamber or the outlet of the vibrating feeding device is provided with a discharge baffle.

Optionally, the feeding reaction tunnel is arranged horizontally or tilted, and at least one dust removal port is provided on the feeding reaction tunnel. When more than two dust removal ports are provided on the feeding reaction tunnel, each dust removal port is provided with an independent or linked dust removal port. Smoke regulating device.

Optionally, the bottom of the feeding reaction tunnel is arranged in a stepped shape that decreases along the feeding direction.

Optionally, at least one smoke detection device is provided in the feeding reaction tunnel.

Optionally, the feeding reaction tunnel is provided with a burner or nozzle for heating into the tunnel.

Optionally, an oxygen gun is provided in the electric furnace corresponding to the dropping point area of the feeding reaction tunnel.

The beneficial effects of the present invention are: the present invention uses the waste heat of the high-temperature flue gas of the electric furnace to realize direct steelmaking with part of the iron concentrate powder. This part of the iron concentrate powder reduces the blast furnace link, reduces emissions, lowers the cost and price of steelmaking raw materials, and improves short-term steelmaking. Process market competitiveness. The addition of iron concentrate powder dilutes harmful elements in scrap steel, which is beneficial to improving the composition quality of molten steel. Reduced scrap demand and dependence.

Description of the drawings

Figure 1 is a schematic diagram of a device of the present invention that utilizes high-temperature electric furnace flue gas and iron concentrate powder to directly make steel (double dust removal ports with associated control);

Figure 2 is a schematic diagram of a device according to the present invention that uses high-temperature electric furnace flue gas and iron concentrate powder to directly make steel (independently controlled dual dust removal ports);

Figure 3 is a schematic diagram of a device of the present invention that utilizes high-temperature electric furnace flue gas and iron concentrate powder to directly make steel (single dust removal port);

Figure 4 is a schematic diagram of a device according to the present invention that utilizes high-temperature electric furnace flue gas and iron concentrate powder to directly make steel (independently controlled dual dust removal ports, the flue gas from two or one of the dust removal ports is directed to the concentrate press ball distribution device );

Figure 5 is a schematic diagram of the concentrate ball distribution device in Figure 4;

Figure 6 is a schematic diagram of another embodiment of the concentrate ball distribution device.

Part number description

1-electric furnace; 2-front section of tunnel; 3-enhanced heating section; 4-burner or nozzle; 5-concentrate ball distribution device; 50-high silo; 51-preheating room; 52-flue gas outlet pipe; 53-baffle; 54-discharge pipe; 55-vibration feeding device; 56-air mixing adjustment device; 57-flue gas inlet pipe; 6-dynamic sealing device; 7-scrap feeding section; 8-scrap steel; 9-precision Mine pressure ball; 10-second dust removal port; 11-first dust removal port; 12-oxygen lance; 13-flue gas regulating device; 14-scrap feeding equipment; 15-electric furnace flue gas; 16-gas; 17-flue gas detection device.

Detailed ways

The implementation of the present invention is described below with specific embodiments. Those familiar with this technology can easily understand other advantages and effects of the present invention from the content disclosed in this specification.

It should be noted that terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for convenience of description and are not used to limit the scope of this specification. The scope of the invention that can be implemented, and changes or adjustments in their relative relationships, as long as there is no substantial change in the technical content, shall also be regarded as the scope of the invention that can be implemented.

The front and rear directions described in this example are such that the end of the feeding reaction tunnel close to the electric furnace 1 is in the front, and the end of the feeding reaction tunnel close to the scrap steel feeding section 7 is in the back.

The invention provides a method for directly making steel by adding high-temperature flue gas from an electric furnace and adding iron concentrate powder, specifically as follows:

Keep more than 30% of the steel in the steelmaking and smelting electric furnace (that is, more than 30% of the molten steel ratio), set up a feeding reaction tunnel to be airtightly connected to the electric furnace 1, and export the flue gas from the electric furnace 1; add the concentrate containing iron concentrate powder and carbon The pressure ball 9 is transported to the electric furnace 1 in the feeding reaction tunnel. The transportation direction is opposite to the flue gas of the electric furnace 1. The concentrate pressure ball 9 is heated by the high-temperature electric furnace 1 flue gas (the temperature of the electric furnace flue gas 15 is generally 1100-1600°C). The electric furnace smoke The gas 15 heats the concentrate press ball 9 to cause a chemical reaction, so that the concentrate press ball 9 reduces part of the iron element, and enters the electric furnace molten pool through the feeding reaction tunnel for smelting.

Specifically, after the reaction, the concentrated ore press balls 9 are added to the electric furnace molten pool through the charging reaction tunnel in the form of a combination of reduced iron, residual ore powder, and residual carbon.

Among them, the concentrate press ball 9 is made by mixing and pressing iron concentrate powder and carbon (a binder can be added), and is in a granular shape; the proportion of iron concentrate powder and carbon in the concentrate press ball 9 can be proportioned into carbon The content can ensure that the iron is completely reduced, and there is even a residual amount of carbon to provide part of the chemical heat source of the electric furnace. Among them, iron concentrate powder can be obtained from iron ore, and carbon can be obtained from coal. The principle is that C reacts with iron concentrate powder at high temperature to generate partially reduced iron.

This invention utilizes the waste heat of high-temperature flue gas from electric furnaces to realize direct steelmaking with part of the iron concentrate powder. This part of the iron concentrate powder reduces the blast furnace link, reduces emissions, lowers the cost and price of steelmaking raw materials, and improves the short-process market competitiveness. The addition of iron concentrate powder dilutes the harmful elements in scrap steel 8, which is beneficial to improving the composition quality of molten steel. Reduced demand and dependence on scrap 8.

In one embodiment, an oxygen lance is installed in the electric furnace to blow oxygen to the blanking point of the molten pool of the electric furnace, thereby strengthening the carbon-oxygen reaction in the molten pool, improving the cold zone of the blanking point, and accelerating the reaction speed of the molten pool. Since the residue after the reaction of the concentrate pressure ball 9 at the blanking point contains carbon, oxygen blowing conditions are provided for the multifunctional oxygen lance.

Among them, the concentrated ore pressing ball 9 enters the electric furnace in the form of a combination of reduced iron, residual ore powder, and residual carbon after reaction.

In one embodiment, the concentrate press balls 9 are laid on the surface of the scrap steel 8 material layer in the feeding reaction tunnel, and the concentrate press balls 9 undergo a ferrite reduction reaction. After the reaction, the concentrate press balls 9 are converted into reduced iron and residual ore powder. , the combined form of residual carbon is mixed with scrap steel 8 and then enters the electric furnace; while the concentrate press ball 9 reacts, the scrap steel 8 can also be heated by the electric furnace flue gas 15 to reduce steelmaking power consumption.

In one embodiment, a burner or nozzle 4 is installed on the feeding reaction tunnel. The gas 16 ejected through the burner or nozzle 4 is burned and heated. The gas 16 from the burner or nozzle 4 and the electric furnace flue gas 15 jointly heat the concentrate pressure. Ball 9. By actively heating the flue gas temperature, maintaining the temperature required for the reaction and stirring the heat exchange between the flue gas and the concentrate press ball 9, the reaction efficiency of the concentrate press ball 9 is improved.

In one embodiment, by increasing the carbon content in the concentrate press ball 9 or adding other combustibles, moderate air or oxygen is provided through the burner or nozzle 4, so that the carbon in the concentrate press ball 9 in the feed reaction tunnel Or combustible materials are burned to provide necessary reaction heat, thereby reducing the gas 16 consumption of the burner or nozzle 4.

In one embodiment, the bottom of the feeding reaction tunnel is arranged in a stepped shape that decreases along the feeding direction (from back to front). The concentrate pressure ball 9 is disturbed and rolled by the steps when being transported in the feeding reaction tunnel, thereby increasing the concentrate pressure. Ball 9 heating uniformity. Since the concentrate pressure ball 9 is at the bottom of the tunnel, and high-temperature flue gas and burner gas 16 flow in the space above the tunnel, in a tunnel with traditional stable vibration transportation, the material running process is relatively stable, and only the surface of the material layer of the concentrate pressure ball 9 is heated. The ladder disturbance causes the material at the bottom and surface of the material layer to flip over after being transported for a certain distance in the tunnel when the material passes through the ladder, so that the material is evenly heated by the flue gas and gas 16, increasing the heat exchange area and improving reaction efficiency.

In one embodiment, distribution is carried out through the concentrate press ball distribution device 5. At least one dust removal port is provided on the feeding reaction tunnel to introduce the electric furnace flue gas 15 into the concentrate press ball distribution device 5 to preheat the concentrate press balls. The heated concentrate press balls 9 are sent into the feeding reaction tunnel through the discharge pipe 4, and are guided to the electric furnace through the feeding reaction tunnel. The electric furnace flue gas 15 is used for preheating before distributing, which increases the preheating temperature and residence time of the concentrate briquettes 9, thereby greatly improving the reduction degree of the iron element in the concentrate briquettes.

Among them, the preheated concentrate pressure balls 9 can be arranged at any point in the feeding reaction tunnel through the discharge pipe 4. Generally, the closer to the end of the feeding reaction tunnel, the better the preheating effect and retention of the concentrate pressure balls. time.

In one embodiment, the flue gas discharged from the dust removal port penetrates the gap between the concentrate press balls in the concentrate press ball distribution device 5, preheats the concentrate press balls penetratingly, and distributes the concentrate press balls through the concentrate press ball distribution device 5. Device 5 controls the feeding speed, preheating time and preheating temperature of the concentrate briquettes according to demand to ensure the degree of reduction of the iron element in the concentrate briquettes.

In one embodiment, the concentrate pellet distribution device 5 is provided with a preheating chamber 51. The top of the preheating chamber 51 is connected to a high-level silo 50. The high-level silo 50 is used to store concentrate pellets. The preheating chamber 51 A vibrating feeding device 55 is connected to the bottom, the flue gas inlet pipe 57 of the preheating chamber 51 is connected to the dust removal port, and the preheating chamber 51 is connected to a flue gas outlet pipe 52 . On the one hand, the vibrating feeding device 55 is used for material distribution, and on the other hand, the contact between the flue gas and the concentrate press ball is increased, thereby improving the heat exchange effect and reaction efficiency.

In one embodiment, the preheating chamber 51 is in the shape of a V-shaped, U-shaped, Y-shaped or L-shaped closed container. Such an arrangement can form a roughly U-shaped curved flue gas route after the flue gas enters the preheating chamber 51, slowing down the flow of gas. The flue gas flow rate extends the contact time of the concentrate pressure balls; or the bottom opening of the preheating chamber 51 and the vibrating feeding device 55 form an inner cavity into a V-shaped, U-shaped, Y-shaped or L-shaped closed container.

In one embodiment, the flue gas outlet pipe 52 of the preheating chamber 51 is connected to a mixed air regulating device 56 .

In one embodiment, a concentrate press ball distribution device 5 is provided at at least one position of the feeding reaction tunnel and is connected to the feeding reaction tunnel for distribution. There is a dynamic sealing device 6 at the end of the feeding reaction tunnel, and there is an open opening behind the dynamic sealing device 6. Scrap steel feeding section 7, in which the concentrate ball distribution device 5 can be arranged in the front of the scrap steel feeding section 7, or at any position in the feeding reaction tunnel, such as behind the dust removal port.

In one embodiment, the feeding reaction tunnel is arranged horizontally or tilted, and at least one dust removal port is provided on the feeding reaction tunnel. When there are more than two dust removal ports at the front and rear of the feeding reaction tunnel, each dust removal port is set independently or in conjunction. flue gas regulating device.

As shown in Figure 1, the present invention also provides a device for directly making steel by adding iron concentrate powder to the high-temperature flue gas of an electric furnace, including a steelmaking electric furnace, a feeding reaction tunnel, scrap steel feeding equipment and a concentrate ball distribution device 5. The front part of the reaction tunnel is tightly connected to the electric furnace, and the tail part is used for feeding scrap steel 8; the scrap steel feeding equipment is used to distribute scrap steel to the feeding reaction tunnel, and the concentrate press ball distribution device 5 is used to distribute concentrate press balls 9 to the feeding reaction tunnel. Tunnel, the feeding reaction tunnel is used to transport scrap steel and concentrate briquettes 9 to the electric furnace.

During the process of the device transporting the scrap steel 8 and the concentrate press balls 9 to the electric furnace, the high-temperature flue gas of the electric furnace moves in reverse relative directions with the scrap steel 8 and the concentrate press balls 9 respectively, thereby heating the scrap steel and the concentrate press balls and making the concentrate The ore pressure ball produces a chemical reaction and reduces the iron element.

In one embodiment, there is a dynamic sealing device 6 at the end of the feeding reaction tunnel, and there is an open scrap steel feeding section 7 behind the dynamic sealing device 6. The scrap steel feeding equipment (such as a disk crane, a chain plate conveyor, etc.) and the The scrap steel feeding section 7 is connected correspondingly. Use the scrap steel feeding equipment to lay scrap steel in the open scrap steel feeding section 7, and then use the concentrate pressure ball distribution device 5 to spread the concentrate pressure balls on the scrap steel layer. The concentrate pressure balls are in the feeding reaction tunnel. The ferrite reduction reaction occurs in the high-temperature environment, and the generated ferrite and the scrap steel layer enter the electric furnace for smelting to complete the steelmaking operation. Scrap steel is also preheated during this process, which can reduce power consumption.

In one embodiment, an oxygen lance is installed in the electric furnace corresponding to the drop point of the charging reaction tunnel, and oxygen is blown to the blanking point of the electric furnace molten pool to strengthen the carbon-oxygen reaction in the molten pool, improve the cold zone of the molten pool at the blanking point, and speed up the Molten pool reaction speed. Since there is carbon in the residue after the concentrate briquetting reaction at the blanking point, oxygen blowing conditions are provided for the oxygen lance.

In one embodiment, the feeding reaction tunnel is provided with a burner or nozzle 4 for heating into the tunnel. The burner gas 16 and the electric furnace flue gas 15 jointly heat the concentrate press balls. The burner or nozzle 4 is inclined downward. Blow from front to back. The function of the burner or nozzle 4 is: due to the long feeding reaction tunnel (the tunnel equipment will take away heat, and the materials will also take away heat), the temperature of the electric furnace flue gas 15 gradually decreases from front to back in the tunnel, in order to maintain a higher temperature. For the reaction temperature, chemical energy must be used to maintain the temperature environment in the reaction tunnel; the burner uses a high-speed jet, which provides a direct impact on the material at the bottom of the reaction tunnel, and can penetrate the surface layer through the gaps in the material, providing a deeper heating depth, thereby improving the tunnel reaction efficiency.

Among them, due to the high temperature in the front section of the feeding reaction tunnel (i.e., the front section of the tunnel 2) close to the electric furnace, the burner or nozzle 4 does not need to be provided; the burner or nozzle 4 is provided in the middle section or the middle and rear section of the feeding reaction tunnel for heating. An enhanced heating section 3 is formed.

In one embodiment, the feeding reaction tunnel is arranged horizontally or tilted, and at least one dust removal port is provided on the feeding reaction tunnel, through which the waste gas is led out; that is, the feeding reaction tunnel where the flue gas and materials are returned is provided with at least one dust removal port. A dust removal port; such as exporting to a dust removal system or cooling system for subsequent processing. When the feeding reaction tunnel is provided with more than two dust removal ports, each dust removal port is provided with an independent or linked flue gas regulating device.

In Figure 1, a first dust removal port 11 and a second dust removal port 10 are respectively provided behind the tunnel front section 2 and the enhanced heating section 3; a concentrate press ball distribution device 5 is provided between the second dust removal port 10 and the dynamic sealing device 6. If there is If necessary, the front part of the scrap feeding section 7 can also be provided with a concentrate ball distribution device 5 .

A first dust removal port 11 and a second dust removal port 10 are respectively provided behind the tunnel front section 2 and the enhanced heating section 3; and the flue gas adjustment device is used for linkage adjustment. This method is conducive to reducing the flow rate and resistance of the flue gas and reducing the concentrate ball pressure. According to the particle size requirements, the heating efficiency of the electric furnace flue gas 15 and the gas 16 on the concentrate press balls is improved, and the reaction speed is improved; reducing the flow rate of the electric furnace flue gas 15 can also reduce the probability of the concentrate press balls being swept away by the flue gas, and improve The recovery rate of concentrate press balls is improved and the air leakage of the dynamic sealing device 6 is improved, and the thermal efficiency of the system is improved; in addition, the flue gas regulating device is also used to control the flue gas temperature so that the subsequent rapid cooling of the flue gas can suppress dioxins, etc. from the source. Synthesis of harmful substances. The flue gas regulating device can use the existing three-way valve or other high temperature resistant valves.

Figure 2 is an implementation example of independent control of two dust removal ports of the present invention. This method can be used when the enhanced heating section 3 is too long. In this solution, separate valves are set up to control the flue gas volume of the first dust removal port 11 and the second dust removal port 10. (not shown in the figure).

Figure 3 is an implementation example of a single dust removal port of the present invention.

In one embodiment, scrap steel and concentrate briquettes can be transported by vibration, typically such as horizontal non-resonant vibration transport or chute vibration transport.

In this example, the bottom of the feeding reaction tunnel is set in a stepped shape that decreases along the feeding direction (from back to front). The concentrate briquettes are disturbed and tumbled by the steps when being transported in the feeding reaction tunnel, which improves the uniform heating of the concentrate briquettes. sex.

In one embodiment, at least one smoke detection device 17 is provided in the feeding reaction tunnel. In this example, multiple flue gas detection devices 17 are installed in the feeding reaction tunnel to detect the components of the flue gas (such as flue gas detectors, flue gas analyzers and other existing equipment), control the feeding speed, and ensure the feeding reaction tunnel as much as possible The flue gas inside maintains a reducing atmosphere or low oxygen content to maintain the reliability of the concentrate press ball reduction reaction.

In one embodiment, the feeding reaction tunnel is provided with at least one dust removal port. The dust removal port is connected to the concentrate press ball distribution device 5 through the flue gas inlet pipe 57 for introducing the electric furnace flue gas 15 into the concentrate press. The concentrate press balls are preheated in the ball distribution device 5. The concentrate press ball distribution device 5 is connected to the feeding reaction tunnel through the discharge pipe 4 and is used to send the preheated concentrate press balls to the feeding reaction tunnel for the feeding reaction. The tunnel leads the concentrate pellets to the electric furnace. The flue gas from any dust removal port (can also be multiple at the same time) is directed to the closed feeding device for concentrate pressure balls, and the flue gas penetrates the concentrate pressure balls stored in the concentrate pressure ball distribution device 5 for preheating.

Referring specifically to Figure 4, two dust removal ports are taken as an example. The concentrate press ball distribution device 5 is provided with a preheating chamber 51. The preheating chamber 51 is connected to the first dust removal port 11 through the flue gas inlet pipe 57. Preheating The top of the chamber 51 is connected to one or more high-level silos 50 for storing concentrate pellets. The bottom of the preheating chamber 51 is connected to a vibration feeding device 55 (chute vibration feeding or horizontal non-resonant vibration feeding). The preheating chamber The 51 outlet is connected to any position of the feeding reaction tunnel through the outlet pipe 4. It can be connected to the front, middle, rear or end of the feeding reaction tunnel. In order to achieve better preheating effect and residence time, it can be connected to The rear section or end; the preheating chamber 51 is also connected to a flue gas outlet pipe 52 for discharging flue gas.

In one embodiment, the flue gas outlet pipe 52 is connected to a mixed air regulating device 56 . The flue gas outlet pipe 52 is equipped with a mixed air regulating device 56. Considering that the reduction reaction that may occur in the concentrate ball preheating chamber 51 produces CO, the combustion of this gas can be used to adjust the temperature of the flue gas discharged from the scrap steel preheating (increasing the temperature has a significant impact on Dioxin control is beneficial). Among them, the mixed air regulating device 56 can be a common device in this field, and can be a flap door or a blast duct.

Figure 5 shows a schematic structural diagram of the concentrate briquette distribution device 5 with preheating function. The bottom of the preheating chamber 51 is connected to the vibration feeding device 55, and the top pipe is connected to the high-level silo 50 to form a closed space for storing concentrate briquettes. . Wherein, the preheating chamber 51 is in the form of a V-shaped, U-shaped, Y-shaped or L-shaped container, or the bottom opening of the preheating chamber 51 is connected to the vibrating feeding device 55 to form a V-shaped, U-shaped, Y-shaped or L-shaped container. .

The flue gas or gas 16 penetrates the gap of the concentrate pressure ball in the V-shaped, U-shaped, Y-shaped or L-shaped container. The preheating chamber 51 is designed into a V-shaped, U-shaped, Y-shaped or L-shaped container mainly to improve the The direction of the flue gas increases the contact area between the high-temperature gas and the concentrate pressure ball (penetration type). In other embodiments, it can also be made into an inclined or horizontal duct structure.

In order to better and accurately control the closed blanking, the discharge baffle 3 can also be provided in the discharge section of the vibrating feeding device 55. The vibrating feeding device 55 is connected to the feeding reaction tunnel through the discharging pipe 54.

Figure 6 shows a schematic structural diagram of the L-shaped preheating chamber 51. The discharge baffle 3 can be eliminated to simplify the structure.

Among them, since the discharge pipe 54 is connected to the feeding reaction tunnel, the discharge pipe 54 will introduce a small amount of flue gas into the preheating chamber 51, which is beneficial to the preheating of the concentrate pressure balls.

The beneficial effects of the present invention are:

1) The present invention uses the waste heat of high-temperature flue gas from electric furnaces to realize direct steelmaking with part of the iron concentrate powder. This part of the iron concentrate powder reduces the blast furnace link, reduces emissions, lowers the cost and price of steelmaking raw materials, and improves the short-process market competitiveness. The addition of iron concentrate powder dilutes harmful elements in scrap steel, which is beneficial to improving the composition quality of molten steel. Reduced scrap demand and dependence.

2) The concentrate press ball distribution device 5 with a preheating chamber 51 is used to control the preheating temperature, preheating time and feeding speed of the concentrate press balls, which can greatly improve the preheating temperature and The residence time thus greatly improves the reduction degree of iron element in the concentrate press balls in this device.

3) Since the cost of scrap steel, the main raw material for electric furnace steelmaking, accounts for 70-75% of the cost of electric furnace steelmaking, the cost of using a mixture of iron concentrate powder and coal is only ~1/2 of that of scrap steel (converted into ferrite) , if it can be achieved that 5-15% of ferrite comes from iron concentrate, and the raw material cost can be reduced by 3-10%, it will bring an additional 100-300 yuan per ton of steel income (recent market price) to electric furnace steelmaking, making it possible to adopt This technology has strong market competitiveness in electric furnace steelmaking.

4) With the gradual improvement of this method and corresponding technologies and the advancement of domestic environmental protection policies in the future, electric furnace steel using this technology will have the basic conditions to compete with the blast furnace-converter long process in the steel market price. Compared with the long process, the carbon emissions, waste residue, wastewater and other emissions of this technology will be greatly reduced. If this technology can partially replace the long process, it will be beneficial to the improvement of the entire human living environment and social progress.

The above embodiments only illustrate the principles and effects of the present invention, but are not intended to limit the present invention. Anyone familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the invention. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the technical field without departing from the spirit and technical ideas disclosed in the present invention shall still be covered by the claims of the present invention.

Claims (25)

1. A method for directly steelmaking by adding iron concentrate powder into high-temperature flue gas of an electric furnace is characterized in that: more than 30% of steel is left in a steelmaking smelting electric furnace, a charging reaction tunnel is arranged and connected to the electric furnace, and flue gas is led out from the electric furnace; the method comprises the steps of reversely conveying concentrate pellets containing iron concentrate powder and carbon to an electric furnace in a feeding reaction tunnel relative to flue gas, heating the concentrate pellets by the flue gas of the electric furnace to reduce part of iron elements from the concentrate pellets, and enabling the concentrate pellets to enter an electric furnace molten pool through the feeding reaction tunnel, wherein the concentrate pellets enter the electric furnace in a combined state of reduced iron, residual mineral powder and residual carbon after reaction; or the concentrate ball pressing is paved on the surface of the waste steel layer of the feeding reaction tunnel, ferrite reduction reaction is carried out on the concentrate ball pressing, and the concentrate ball pressing enters an electric furnace together with waste steel in a combination form of reduced iron, residual mineral powder and residual carbon after the concentrate ball pressing reaction.

2. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 1, which is characterized in that: an oxygen gun is arranged in the electric furnace to blow oxygen to the blanking point of the electric furnace molten pool, so as to strengthen the carbon-oxygen reaction in the molten pool.

3. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 1, which is characterized in that: and a burner or a nozzle is arranged on the feeding reaction tunnel, and the burner or nozzle fuel gas and the electric furnace flue gas are combined to heat the concentrate pressing balls.

4. The method for directly steelmaking by using the high-temperature flue gas of the electric furnace and the iron concentrate powder according to claim 3, wherein the method comprises the following steps of: the content of carbon in the concentrate pellets is increased or combustible substances are added, air or oxygen is provided through a burner or a nozzle, the carbon or the combustible substances in the concentrate pellets in a feeding reaction tunnel are combusted, necessary reaction heat is provided, and the fuel consumption of the burner or the nozzle is reduced.

5. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 1, which is characterized in that: the bottom of the feeding reaction tunnel is arranged to be stepped along the feeding direction, and the concentrate ball is rolled by stepped disturbance when conveyed in the feeding reaction tunnel, so that the heating uniformity of the concentrate ball is improved.

6. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 1, which is characterized in that: the concentrate ball pressing and distributing device is used for distributing materials, at least one dust removing port is arranged on the feeding reaction tunnel to guide the flue gas of the electric furnace into the concentrate ball pressing and distributing device to preheat the concentrate balls, and the preheated concentrate balls are fed into the feeding reaction tunnel through a discharging pipeline and are guided to the electric furnace through the feeding reaction tunnel.

7. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 6, wherein the method comprises the following steps of: and flue gas discharged from the dust removal port penetrates through a gap of the concentrate ball in the concentrate ball pressing and distributing device, so as to carry out penetrating preheating on the concentrate ball pressing, and the concentrate ball pressing and feeding speed, the preheating time and the preheating temperature are controlled through the concentrate ball pressing and distributing device.

8. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 6, wherein the method comprises the following steps of: the concentrate ball-pressing and distributing device is provided with a preheating chamber, a connecting pipe at the top of the preheating chamber is connected with a high-level stock bin, the bottom of the preheating chamber is connected with a vibration feeding device, a flue gas inlet pipe of the preheating chamber is connected with a dust removal port, and the preheating chamber is connected with a flue gas outlet pipe.

9. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 8, wherein the method comprises the following steps of: the preheating chamber is a V-shaped, U-shaped, Y-shaped or L-shaped container, or the preheating chamber and the vibration feeding device form a V-shaped, U-shaped, Y-shaped or L-shaped container; the flue gas outlet pipe of the preheating chamber is connected with a mixing air adjusting device.

10. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 1, which is characterized in that: and at least one position of the feeding reaction tunnel is provided with a concentrate ball pressing and distributing device which is connected with the feeding reaction tunnel for distributing, the tail part of the feeding reaction tunnel is provided with a dynamic sealing device, and an open scrap steel feeding section is arranged behind the dynamic sealing device.

11. The method for directly steelmaking by utilizing high-temperature flue gas of an electric furnace and adding iron concentrate powder according to claim 1, which is characterized in that: the feeding reaction tunnel is horizontally or obliquely arranged, at least one dust removing opening is arranged on the feeding reaction tunnel, and when more than two dust removing openings are arranged on the feeding reaction tunnel, each dust removing opening is provided with an independent or linked smoke adjusting device.

12. A device for directly steelmaking by adding iron concentrate powder into high-temperature flue gas of an electric furnace is characterized in that: the feeding reaction tunnel is used for guiding out smoke from the electric furnace and conveying the waste steel and concentrate balls to the electric furnace.

13. The apparatus for directly steelmaking utilizing high temperature flue gas of an electric furnace and iron concentrate powder as defined in claim 12 wherein: the tail part of the feeding reaction tunnel is provided with a dynamic sealing device, an open scrap steel feeding section is arranged behind the dynamic sealing device, and scrap steel feeding equipment and the scrap steel feeding section are correspondingly arranged.

14. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron concentrate powder as defined in claim 13 wherein: the front part of the scrap steel feeding section is provided with a concentrate ball pressing and distributing device and/or a concentrate ball pressing and distributing device is arranged on a feeding reaction tunnel in front of the dynamic sealing device.

15. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron concentrate powder as defined in claim 14 wherein: the feeding reaction tunnel is provided with a dust removal port, the dust removal port is communicated with the concentrate ball pressing and distributing device through a flue gas inlet pipe and is used for guiding flue gas of an electric furnace into the concentrate ball pressing and distributing device to preheat concentrate balls, and the concentrate ball pressing and distributing device is connected with the feeding reaction tunnel through a discharge pipe and is used for conveying preheated concentrate balls to the feeding reaction tunnel.

16. The apparatus for directly steelmaking utilizing high temperature flue gas of an electric furnace and iron concentrate powder as defined in claim 15 wherein: the discharging pipe is connected to the tail part or the middle rear section of the feeding reaction tunnel.

17. The apparatus for directly steelmaking utilizing high temperature flue gas of an electric furnace and iron concentrate powder as defined in claim 15 wherein: the concentrate ball pressing and distributing device is provided with a preheating chamber, a connecting pipe at the top of the preheating chamber is connected with a high-level stock bin, the bottom of the preheating chamber is connected with a vibration feeding device, a flue gas inlet pipe is connected to the preheating chamber, and the preheating chamber is connected with a flue gas outlet pipe.

18. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron concentrate powder as defined in claim 17 wherein: the preheating chamber is a V-shaped, U-shaped, Y-shaped or L-shaped container, or the preheating chamber and the vibration feeding device form a V-shaped, U-shaped, Y-shaped or L-shaped container.

19. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron concentrate powder as defined in claim 17 wherein: the flue gas outlet pipe of the preheating chamber is connected with a mixing air adjusting device.

20. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron concentrate powder as defined in claim 17 wherein: and a discharging baffle is arranged at the outlet of the preheating chamber or the outlet of the vibration feeding device.

21. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron ore concentrate powder as in any one of claims 12-20, wherein: the feeding reaction tunnel is horizontally or obliquely arranged, at least one dust removing opening is arranged on the feeding reaction tunnel, and when more than two dust removing openings are arranged on the feeding reaction tunnel, each dust removing opening is provided with an independent or linked smoke adjusting device.

22. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron ore concentrate powder as in any one of claims 12-20, wherein: the bottom of the feeding reaction tunnel is arranged in a stepped shape which is lowered along the feeding direction.

23. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron ore concentrate powder as in any one of claims 12-20, wherein: at least one smoke detection device is arranged in the feeding reaction tunnel.

24. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron ore concentrate powder as in any one of claims 12-20, wherein: and a burner or a nozzle for heating the tunnel is arranged on the feeding reaction tunnel.

25. The apparatus for directly steelmaking utilizing electric furnace high temperature flue gas and iron ore concentrate powder as in any one of claims 12-20, wherein: an oxygen gun is arranged in the electric furnace corresponding to the blanking point area of the feeding reaction tunnel.