Steel slag graded utilization and waste heat recovery device

Abstract

The utility model discloses a steel slag grading utilization and waste heat recovery device which comprises an electric heating furnace 1, a slag granulator 2, a slag tank 3, a molten iron tank 4, a gravity dust collector 5, a heat exchanger 6 and a flue gas separation system 7. According to the system and method for efficient treatment and resource utilization of molten steel slag, iron resources and steel slag treatment tailings are utilized, the process iron element recovery rate reaches 90%, free calcium oxide in the steel slag is fully digested, the traditional steel slag utilization problem is thoroughly solved, in addition, waste heat is fully absorbed, and the utilization rate of the steel slag is increased. And byproducts carbon monoxide and carbon dioxide in the production process can be recovered.

Description

Technical Field

[0001] The utility model belongs to the technical field of steel slag treatment, and relates to a steel slag resource utilization device, in particular to a steel slag classification utilization and waste heat recovery device. Background Art

[0002] After the mainstream process of steel slag resource utilization, nearly 80% of the steel slag tailings still remain and cannot be effectively utilized. At present, the steel slag treatment is mainly based on the hot stuffing method, but hot stuffing can only partially solve the stabilization problem of steel slag, and cannot completely solve the expansion and cracking problems caused by the tailings utilization process and the waste heat recovery problem. Summary of the invention

[0003] In view of the shortcomings of the above-mentioned existing molten steel slag utilization technology, the utility model discloses a steel slag classification utilization and waste heat recovery device, which can fully utilize the waste heat resources of molten high-temperature steel slag, and utilize iron resources and steel slag processing tailings to efficiently process and resource-utilize molten steel slag. In order to achieve the above-mentioned technical purpose, the utility model adopts the following technical solutions:

[0004] A slag grading utilization and waste heat recovery device, comprising an electric furnace, a slag granulator, a slag pot, a molten iron pot, a gravity dust removal, a heat exchanger, and a flue gas separation system, characterized in that: the slag pot is used to transport molten slag between a steelmaking slag field and the electric furnace, and the transported molten slag is fed into the electric furnace through a feed hopper on the side of the electric furnace, the flue gas outlet of the electric furnace is connected to the gravity dust removal through a pipeline, the flue gas after gravity dust removal enters the heat exchanger for heat recovery, and the flue gas after heat exchange enters the flue gas separation system for treatment; the slag liquid in the electric furnace is connected to the granulator through a slag discharge pipe through a slag outlet, and the molten iron in the electric furnace is discharged into the molten iron pot through an iron outlet and an iron outlet ditch;

[0005] The electric heating furnace is provided with a dome on the top, a smoke outlet is provided in the middle of the dome, and an oxygen gun is installed on the dome outside the smoke outlet; a feed hopper is installed at 1 / 4 of the height of the upper part of the side wall of the electric heating furnace, an iron outlet is opened at the bottom of the side wall, and a slag outlet is provided at 1 / 4 of the height of the bottom opposite to the iron outlet; the bottom surface of the electric heating furnace is concave, a bottom blowing nozzle is provided in the middle, and three-phase industrial frequency electrodes are evenly distributed and installed around the bottom blowing nozzle.

[0006] The top cover of the granulator is a hemispherical structure, a steam outlet is arranged in the middle of the hemisphere, more than four high-pressure water nozzles are evenly arranged inwardly around it, the bottom of the hemisphere is connected to the cylindrical body, a rotating disk is arranged inside the body, the rotating disk passes through the bottom of the granulator through a connecting shaft and is connected to a rotating motor, a granulating screen is arranged below the rotating disk, and a slag bin is arranged below the granulating screen.

[0007] The flue gas separation system includes a blower, a first gas separation, a booster fan, and a second gas separation. The flue gas whose waste heat is recovered by the heat exchanger enters the flue gas separation system and then enters the first gas separation system under the action of the blower to separate the carbon monoxide in the flue gas for recovery. The remaining flue gas is pressurized by the booster fan and enters the second gas separation device to separate the carbon dioxide for recovery. The remaining waste gas is discharged after effective treatment.

[0008] The beneficial effects of the steel slag grading utilization and waste heat recovery device of the present application compared with the prior art are: the sensible heat of the molten steel slag is utilized to fully recover the residual iron in the steel slag, the process iron element recovery rate reaches 90%, the free calcium oxide in the steel slag is fully eliminated, and the problem of traditional steel slag utilization is completely solved. In addition, the waste heat is fully absorbed, and the by-products of the production process, carbon monoxide and carbon dioxide, can be recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the embodiments of the present utility model, the drawings required for use in the embodiments are briefly introduced below.

[0010] Figure 1 This is a schematic diagram of the overall structure of the utility model system;

[0011] in:

[0012] Electric heating furnace, 2-slag granulator, 3-slag pot, 4-molten iron pot, 5-gravity dust removal, 6-heat exchanger, 7-flue gas separation system, 11-flue gas outlet, 12-oxygen gun, 13-slag discharge pipe, 14-slag outlet, 15-feed hopper, 16-slag liquid, 17-molten iron, 18-iron outlet, 19-iron outlet ditch, 110-electrode, 111-bottom blowing nozzle, 21-steam outlet, 22-rotating disk, 23-high-pressure water nozzle, 24-granulating screen, 25-rotating motor, 26-slag bin, 71-blower, 72-boosting fan, 73-first gas separation, 74-second gas separation. DETAILED DESCRIPTION

[0013] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0014] In the description of the present utility model, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "one side", "one end", "one side" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present utility model, unless otherwise specified, "multiple" means two or more.

[0015] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0016] It should be understood that when used in this specification and the appended claims, the terms "include" and "comprises" indicate the presence of described features, integers, steps, operations, elements and / or components, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or combinations thereof.

[0017] It should also be understood that the terms used in the utility model specification are only for the purpose of describing specific embodiments and are not intended to limit the utility model. As used in the utility model specification and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an" and "the" are intended to include plural forms.

[0018] It should be further understood that the term "and / or" used in this specification and the appended claims refers to and includes any and all possible combinations of one or more of the associated listed items.

[0019] The accompanying drawings show various structural schematic diagrams of the embodiments disclosed in the utility model. These figures are not drawn to scale, and some details are magnified and some details may be omitted for the purpose of clear expression. The shapes of various regions and layers shown in the figures and the relative sizes and positional relationships therebetween are only exemplary, and may deviate in practice due to manufacturing tolerances or technical limitations, and those skilled in the art may additionally design regions / layers with different shapes, sizes, and relative positions according to actual needs.

[0020] Referring to the attached drawings, the present application discloses a slag classification utilization and waste heat recovery device, comprising an electric furnace 1, a slag granulator 2, a slag pot 3, a molten iron pot 4, a gravity dust collector 5, a heat exchanger 6, and a flue gas separation system 7, characterized in that: the slag pot 3 is used to transport molten slag between the steelmaking slag field and the electric furnace 1, and the transported molten slag is fed into the electric furnace 1 through a feed hopper 15 on the side of the electric furnace 1, the flue gas outlet 11 of the electric furnace 1 is connected to the gravity dust collector 5 through a pipeline, the flue gas after the gravity dust collector 5 enters the heat exchanger 6 for heat recovery, and the flue gas after heat exchange enters the flue gas separation system 7 for treatment; the slag liquid 16 in the electric furnace 1 is connected to the granulator 2 through the slag outlet 14 by the slag discharge pipe 13, and the molten iron 17 in the electric furnace 1 is discharged into the molten iron pot 4 through the iron outlet 18 and the iron outlet ditch 19;

[0021] The electric heating furnace 1 is provided with a dome on the top, a smoke outlet 11 is provided at the center of the dome, and an oxygen gun 12 is installed on the dome outside the smoke outlet 11; a feed hopper 15 is installed at the upper 1 / 4 height of the side wall of the electric heating furnace 1, an iron outlet 18 is opened at the bottom of the side wall, and a slag outlet 14 is provided at the 1 / 4 height of the bottom opposite to the iron outlet 18; the bottom surface of the electric heating furnace 1 is concave, and a bottom blowing nozzle 111 is provided at the center thereof, and three-phase industrial frequency electrodes 110 are evenly distributed and installed around the bottom blowing nozzle 111.

[0022] The feed hopper 15 is loaded with molten steel slag and reducing agent in batches; the reducing agent is one or more carbon-containing materials selected from coal powder, semi-coke and coke, and semi-coke is preferably used as a low-cost reducing agent. The carbon content in the reducing agent is not less than 60%, and the mass percentage of particles with a particle size of 0-5 mm exceeds 90%. The amount of reducing agent added per ton of molten steel slag is 40-160 kg.

[0023] The smelting cycle of molten steel slag in the electric furnace 1 is 20 to 100 minutes. The smelting cycle is relatively long in the early stage of smelting, and is relatively short in the later stage of smelting. After the electric furnace 1 smelts 2 to 5 cans of molten steel slag, the accumulated slag liquid needs to open the slag outlet 14 for slag discharge operation. The slag outlet 14 on the furnace wall of the electric furnace 1 is opened, and the slag liquid enters the granulator 2 through the slag discharge pipe 13. After the molten slag liquid above the slag outlet 14 is completely discharged, the slag outlet 14 is blocked to stop the slag discharge operation.

[0024] When it is monitored that the liquid level of the reduced molten iron 17 in the electric furnace 1 is close to the bottom of the slag outlet 14, the iron outlet 18 is opened, and the molten iron 17 enters the molten iron tank through the iron outlet 18 and the iron outlet ditch 19. When it is monitored that the liquid level of the molten iron 17 drops to the upper edge of the iron outlet 18, the iron outlet 18 is blocked to stop the iron tapping.

[0025] The top cover of the granulator 2 is a hemispherical structure, a steam outlet 21 is provided in the middle of the hemisphere, and a plurality of high-pressure water nozzles 23 are evenly arranged inwardly around it. The bottom of the hemisphere is connected to a cylindrical body, and a rotating disk 22 is provided inside the body. The rotating disk 22 passes through the bottom of the granulator 2 through a connecting shaft and is connected to a rotating motor 25. A granulating screen 24 that rotates synchronously with the rotating disk 22 is provided below the rotating disk 22, and a slag bin 26 is provided below the granulating screen 24.

[0026] The outlet of the slag discharge pipe 13 is aligned with the center position of the rotating disk 22;

[0027] The rotating disk 22 rotates at a high speed driven by the rotating motor 25. After the slag liquid 16 enters the high-speed rotating disk 22, it is thrown into slag drops under the action of centrifugal force and quickly splashes to the surroundings. At the same time, the water mist sprayed by multiple high-pressure water nozzles 23 in the granulator 2 quickly cools the surface of the slag particles and quickly forms a crust. At this time, due to the large temperature difference between the inside and outside of the slag droplets, the slag particles are broken again to form slag particles. At the same time, under the action of gravity, the slag particles fall down. When reaching the granulating screen 24, the larger slag particles are crushed again by the high-speed rotating granulating screen 24 and fall into the slag bin. Due to the residual heat of the slag particles themselves and the water vapor that has not completely evaporated in the water mist, the slag particles that fall into the slag bin further strengthen the digestion of free calcium oxide in the slag bin.

[0028] The flue gas separation system includes a blower 71, a first gas separation 73, a booster fan 72, and a second gas separation 74. The flue gas whose waste heat is recovered by the heat exchanger 6 enters the flue gas separation system 7 and then enters the first gas separation 73 system under the action of the blower 71 to separate the carbon monoxide in the flue gas for recovery. The remaining flue gas is pressurized by the booster fan 72 and enters the second gas separation 74 device to separate the carbon dioxide for recovery. The remaining waste gas is discharged after being effectively treated.

[0029] The first gas separation 73 and the second gas separation 74 are preferably molecular sieve pressure swing adsorption devices.

Claims

1. A steel slag classification utilization and waste heat recovery device, comprising an electric heating furnace (1), a slag granulator (2), a slag pot (3), a molten iron pot (4), a gravity dust removal (5), a heat exchanger (6), and a flue gas separation system (7), characterized in that: The slag pot (3) is used to transport molten steel slag between the steelmaking slag field and the electric heating furnace (1), and the transported molten steel slag is fed into the electric heating furnace (1) through a feed hopper (15) on the side of the electric heating furnace (1); the flue gas outlet (11) of the electric heating furnace (1) is connected to a gravity dust collector (5) through a pipeline; the flue gas after the gravity dust collector (5) enters a heat exchanger (6) for heat recovery; the flue gas after heat exchange enters a flue gas separation system (7) for treatment; the slag liquid (16) in the electric heating furnace (1) is connected to the granulator (2) through a slag outlet (14) and a slag discharge pipe (13); the molten iron (17) in the electric heating furnace (1) is discharged into the molten iron pot (4) through an iron outlet (18) and an iron outlet ditch (19).

2. The device for grading and recovering waste heat of steel slag according to claim 1, characterized in that: The electric heating furnace (1) has a dome on the top, a smoke outlet (11) is provided at the center of the dome, and an oxygen gun (12) is installed on the dome outside the smoke outlet (11); a feed hopper (15) is installed at 1 / 4 of the height of the upper part of the side wall of the electric heating furnace (1), an iron outlet (18) is opened at the bottom of the side wall, and a slag outlet (14) is provided at 1 / 4 of the height of the bottom opposite to the iron outlet (18); the bottom surface of the electric heating furnace (1) is concave, and a bottom blowing nozzle (111) is provided at the center thereof, and three-phase industrial frequency electrodes (110) are evenly distributed and installed around the bottom blowing nozzle (111).

3. The device for grading and recovering waste heat of steel slag according to claim 1, characterized in that: The feed hopper (15) is loaded with molten steel slag and reducing agent in batches.

4. The device for grading and recovering waste heat of steel slag according to claim 1, characterized in that: The top cover of the granulator (2) is a hemispherical structure, a steam outlet (21) is provided in the middle of the hemisphere, and a plurality of high-pressure water spray nozzles (23) are evenly arranged inwardly around the hemisphere. The bottom of the hemisphere is connected to a cylindrical body, and a rotating disk (22) is provided inside the body. The rotating disk (22) passes through the bottom of the granulator (2) through a connecting shaft and is connected to a rotating motor (25). A granulating screen (24) that rotates synchronously with the rotating disk (22) is provided below the rotating disk (22), and a slag bin (26) is provided below the granulating screen (24).

5. The slag classification utilization and waste heat recovery device according to claim 1, characterized in that: The outlet of the slag discharge pipe (13) is aligned with the center position of the rotating disk (22).

6. The device for grading and recovering waste heat of steel slag according to claim 1, characterized in that: The flue gas separation system comprises a blower (71), a first gas separation (73), a booster fan (72), and a second gas separation (74); the flue gas after waste heat is recovered by the heat exchanger (6) enters the flue gas separation system (7), and then enters the first gas separation (73) system under the action of the blower (71) to separate carbon monoxide from the flue gas for recovery; the remaining flue gas is pressurized by the booster fan (72) and enters the second gas separation (74) device to separate carbon dioxide for recovery; and the remaining waste gas is effectively treated and then discharged; The first gas separation (73) and the second gas separation (74) are performed using a molecular sieve pressure swing adsorption device.

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