Device for hot disintegration and carbonization of steel slag

Abstract

The utility model discloses a device for thermally disintegrating and carbonizing steel slag. The device comprises a thermal banking furnace, an air inlet pipe, an air inlet pipe and an air outlet pipe, the air inlet pipe is connected with the air inlet pipe, and the end part of the air inlet pipe extends into the hot banking furnace; one end of the gas outlet pipe is connected with the side surface of the top of the hot banking furnace, and the other end is connected to an external tail gas treatment unit; the middle part of the air outlet pipe is reconnected into the air inlet pipe through a branch pipe, and unreacted tail gas in the hot banking furnace is refed into the air inlet pipe through the air inlet pipe. A carbonization treatment process is introduced into a steel slag pyrolytic device, and wet carbonation conditions are created by mixing water vapor and lime tail gas, so that the utilization rate of the lime tail gas is increased, CO2 is fixed in the steel slag, and resource utilization of the steel slag is realized.

Description

Technical Field

[0001] This utility model belongs to the field of hot quenching steel slag technology, specifically relating to a device for hot quenching carburized steel slag. Background Technology

[0002] Steel slag is a byproduct of steelmaking, primarily originating from converters, electric furnaces, or refining furnaces. It mainly consists of oxides such as CaO, SiO2, MgO, and FeO, and also contains free CaO and MgO. While steel slag has high hardness, the free CaO and MgO within it undergo hydration reactions upon contact with water, causing volume expansion and affecting its volume stability, thus limiting its application in the construction industry. Direct stockpiling or landfilling of steel slag occupies significant land resources, and harmful substances in the slag may seep into the soil and water bodies, leading to environmental pollution.

[0003] To address the aforementioned issues, hot quenching technology utilizes high-temperature steam to treat steel slag, accelerating the hydration of free CaO and MgO to generate stable hydroxides. This significantly improves the volume stability of the steel slag, and the processing speed is far faster than natural weathering. The hot quenching device mainly consists of a hot quenching pit, a hot quenching cover, and side wall vents. Its working principle is as follows: The hot quenching pit, located at the bottom of the equipment, is used to hold the steel slag and has sufficient depth and capacity to accommodate a large amount of slag. The hot quenching cover, located at the top, tightly seals the hot quenching pit to prevent air and steam leakage. Multiple vents are located on the side walls of the hot quenching cover to release gases generated during the steel slag cooling process, ensuring pressure balance and preventing excessive gas accumulation. Steam pipes are connected to the vents, periodically injecting steam to accelerate the cooling process and control gas emissions, preventing environmental impact. This technology completes steel slag stabilization within hours, offering high efficiency and safety. This type of heat-quenching device has two main drawbacks: First, the high-temperature steam released during the cooling of the steel slag contains flammable and explosive gases such as hydrogen. Because of their low density, these gases tend to accumulate at the bottom of the heat-quenching cover. If the concentration reaches a certain level, they can easily come into contact with open flames inside the pit, potentially causing an explosion and posing a safety hazard. Second, the seal between the heat-quenching cover and the heat-quenching pit is poor, allowing high-temperature steam to leak through gaps, which could burn workers. Furthermore, when heat-quenched steel slag is used in the building materials industry, it can still cause concrete cracking and road surface bursts.

[0004] Existing hot-quenching technology for steel slag has limited effect on improving the volume stability of steel slag. Therefore, a method is needed to significantly improve the volume stability of steel slag, substantially reduce the free calcium oxide and free magnesium oxide components in the steel slag, enhance the stability of steel slag, and promote the widespread application of high-value steel slag in the building materials industry. Summary of the Invention

[0005] Purpose of this utility model: The technical problem to be solved by this utility model is to address the shortcomings of existing technologies by providing a device for hot-quenching and carbonizing steel slag. This device aims to solve problems such as further eliminating free CaO and MgO in steel slag and improving its poor volume stability and low cementitious activity. It also prevents volume expansion of the steel slag during its use in the building materials industry, reduces environmental pollution from steel slag, and contributes to carbon dioxide emission reduction.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] An apparatus for hot-quenching carburizing steel slag includes a hot-quenching furnace, an air inlet pipe, an air inlet pipe, and an air outlet pipe; the air inlet pipe is connected to the air inlet pipe, and the end of the air inlet pipe extends into the hot-quenching furnace; one end of the air outlet pipe is connected to the top side of the hot-quenching furnace, and the other end is connected to an external exhaust gas treatment unit; the middle part of the air outlet pipe is reconnected to the air inlet pipe through a branch pipe, so that unreacted exhaust gas in the hot-quenching furnace is sent back into the air inlet pipe through the air inlet pipe.

[0008] A blower forces lime tail gas into the bottom of the hot-quenching furnace, where it enters the steel slag layer for carbonization. This allows the gas to rise evenly through the slag layer and reach the upper part of the furnace. Multiple evenly spaced vents connected to a vent pipe are located along one side of the furnace's upper edge. The vent pipe is equipped with a pressure-limiting valve. When the furnace pressure exceeds the pressure-limiting valve, the valve opens, allowing the lime tail gas to re-enter the vent pipe via a circulation switch and continue carbonization within the furnace.

[0009] In this invention, the hot-quenched carbonized steel slag can be any one of converter slag, electric furnace slag, or ladle refining slag.

[0010] Furthermore, the hot-bake oven is equipped with a furnace chamber, and a porous steel cap protruding inward is provided at the center of the bottom of the furnace chamber; the end of the air inlet pipe extends into the porous steel cap.

[0011] Furthermore, the bottom of the furnace liner inside the hot-pressing furnace is surrounded by a set of aluminum micro-castings to elevate the furnace liner so that it does not contact the bottom of the hot-pressing furnace.

[0012] Furthermore, the hot oven has an opening at the top and is equipped with an oven lid for opening and closing.

[0013] Furthermore, a pressure limiting valve is installed inside the exhaust pipe. When the pressure inside the furnace exceeds 8000 Pa, the pressure limiting valve opens, and the lime tail gas re-enters the intake pipe through the circulation switch and is sent into the furnace for continuous carbonization.

[0014] Furthermore, a circulation switch is installed in the branch pipe in the middle of the air outlet pipe that connects to the air inlet pipe.

[0015] Furthermore, a high-pressure centrifuge or Roots blower is connected to the front end of the air inlet pipe. Lime exhaust gas is blown in and maintained at a pressure of approximately 5000 Pa, causing the steel slag to undergo partial carbonization in the high-temperature, high-moisture environment of the furnace.

[0016] Furthermore, a set of vent holes connected to a vent pipe are provided on the top side of the hot oven.

[0017] Furthermore, the pressure of the pressure-limiting valve is adjustable, limited to not lifting the furnace cover of the hot oven.

[0018] Furthermore, the height of the top of the porous steel cap exceeds half the depth of the furnace liner. Beneficial effects

[0019] (1) To ensure the safety of the furnace, the connection structure between the upper edge of the furnace and the furnace cover was optimized, and high-performance sealing materials were used to ensure a tight fit between the furnace cover and the upper edge of the furnace, reducing steam leakage. A counterweight was added to the furnace cover design to apply a certain pressure to the inside of the furnace when it is closed, thereby further enhancing the sealing effect. Simultaneously, multiple vent holes were evenly opened on one side of the upper edge of the furnace to ensure that the gas generated during the hot sealing process can be discharged evenly, avoiding excessively high local pressure. Each vent hole is connected to a vent pipe, and the outlet of the vent pipe is equipped with a pressure limiting valve for real-time adjustment and monitoring of the internal pressure of the furnace. The pressure limiting valve can automatically adjust the gas discharge according to the preset pressure value to ensure stable internal pressure and prevent safety hazards caused by excessive pressure. Furthermore, by improving sealing and pressure control, the risk of high-temperature steam leakage through gaps was significantly reduced, thus avoiding burns to operators. To further ensure operational safety, protective railings and warning signs were installed around the furnace, and operators were required to wear high-temperature resistant gloves, masks, and other protective equipment.

[0020] (2) This utility model realizes the hot quenching of steel slag using high temperature and steam to promote the reaction of free CaO and MgO in the steel slag with water to generate stable hydroxides. The reaction equations (1-2) are as follows. During the hot quenching, lime tail gas is introduced into the steel slag for carbonation treatment. The alkaline oxides (such as CaO and MgO) and hydroxides in the steel slag react with CO2 to generate carbonates. The reaction equations (3-6) are as follows. The reaction will further consume the free CaO and MgO in the steel slag, improve the volume stability of the steel slag, and form a dense carbonized layer on the surface of the steel slag after carbonation. This can make the carbonized steel slag produce higher particle strength and be used as concrete aggregate. At the same time, it can make the carbonized steel slag powder have a certain activity, replacing part of the cement as a blending material and admixture.

[0021]

[0022] (3) By introducing a carbonation process into the hot quenching steel slag device, this utility model creates wet carbonation conditions by using mixed steam and lime tail gas, which not only improves the utilization rate of lime tail gas, but also fixes CO2 in the steel slag, thus realizing the resource utilization of steel slag. Attached Figure Description

[0023] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0024] Figure 1 This is a schematic diagram of the overall structure of the hot quenching steel slag device of this utility model.

[0025] The reference numerals in the attached figures represent:

[0026] 1-Inlet pipe; 2-Circulation switch; 3-Outlet pipe; 4-Blower; 5-Inlet pipe; 6-Pressure relief valve; 7-Furnace cover; 8-Furnace liner; 9-Perforated steel cap; 10-Aluminum microcasting. Detailed Implementation

[0027] The present invention can be better understood from the following embodiments.

[0028] The structures, proportions, and sizes shown in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art. They are not intended to limit the scope of this invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, provided they do not affect the effectiveness or purpose of this invention, should still fall within the scope of the technical content disclosed in this invention. Furthermore, terms such as "upper," "lower," "front," "rear," and "middle" used in this specification are merely for clarity and not intended to limit the scope of this invention. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of this invention.

[0029] Combination Figure 1 As shown, the device for hot-quenching carbonized steel slag of this utility model includes a hot-quenching furnace, an air inlet pipe 1, an air inlet pipe 5, and an air outlet pipe 3; the air inlet pipe 1 is connected to the air inlet pipe 5, and the end of the air inlet pipe 5 extends into the hot-quenching furnace; one end of the air outlet pipe 3 is connected to the top side of the hot-quenching furnace, and the other end is connected to an external exhaust gas treatment unit; the middle part of the air outlet pipe 3 is reconnected to the air inlet pipe 1 through a branch pipe, so that the unreacted exhaust gas in the hot-quenching furnace is sent back into the air inlet pipe 5 through the air inlet pipe 1.

[0030] In this invention, the hot-quenched carbonized steel slag can be any one of converter slag, electric furnace slag, or ladle refining slag.

[0031] The hot-bake oven is equipped with a furnace chamber 8, and a perforated steel cap 9 protruding inward is provided at the center of the bottom of the furnace chamber 8; the end of the air inlet pipe 5 extends into the perforated steel cap 9.

[0032] The bottom of the furnace liner 8 inside the hot-drying furnace is surrounded by a set of aluminum micro-casting 10, which is used to lift the furnace liner 8 so that it does not contact the bottom of the hot-drying furnace.

[0033] The hot oven has an opening at the top and is equipped with a lid 7 for opening and closing. High-performance sealing materials are used to ensure a tight seal between the lid 7 and the upper edge of the oven, reducing steam leakage. A counterweight is added to the lid 7 design, which applies pressure to the interior of the oven when closed, further enhancing the sealing effect.

[0034] A pressure limiting valve 6 is installed inside the gas outlet pipe 3. When the pressure inside the furnace exceeds 8000 Pa, the pressure limiting valve opens, and the lime tail gas re-enters the gas inlet pipe through the circulation switch and is sent into the furnace for continuous carbonization.

[0035] A circulation switch 2 is installed in the branch pipe in the middle of the air outlet pipe 3 that connects to the air inlet pipe 1.

[0036] The front end of the air inlet duct 1 is connected to a high-pressure centrifuge or a Roots blower. Lime exhaust gas is blown in and maintained at a pressure of about 5000 Pa, so that the steel slag undergoes partial carbonization in the high temperature and high moisture content of the furnace.

[0037] A set of vent holes is provided on the top side of the hot oven and connected to the vent pipe 3.

[0038] The pressure relief valve 6 has adjustable pressure, limited to not lifting the furnace cover of the hot oven.

[0039] The top height of the porous steel cap 9 exceeds half the depth of the furnace liner 8.

[0040] A blower forces lime tail gas into the bottom of the hot-quenching furnace, where it enters the steel slag layer for carbonization. This allows the gas to rise evenly through the slag layer and reach the upper part of the furnace. Multiple evenly spaced vents connected to a vent pipe are located along one side of the furnace's upper edge. The vent pipe is equipped with a pressure-limiting valve. When the furnace pressure exceeds the pressure-limiting valve, the valve opens, allowing the lime tail gas to re-enter the vent pipe via a circulation switch and continue carbonization within the furnace.

[0041] The process flow for hot quenching and carbonization of steel slag using this device is as follows:

[0042] (1) Cooling, solidification, and coarse crushing: After the molten liquid steel slag is cooled, solidified, and crushed to a solid hot steel slag with a temperature of 600-800℃ and a particle size of less than 300mm, it enters the furnace chamber through a chute. This process is accompanied by normal alternating water pulverization and cooling, which generates a large amount of water vapor. During this process, the furnace cover 7 is closed to slag trap, so as to maintain the sealing of the furnace environment, ensure that the water vapor is effectively controlled, and prevent external air from entering.

[0043] (2) Hot quenching and slag loading: The furnace liner 8 is lowered into the device by a crane, and then the furnace cover 7 is covered. Ensure that the joint between the furnace liner 8 and the furnace cover 7 is locked and sealed to prevent any gas leakage and ensure airtightness so that the subsequent hot quenching operation can be carried out effectively.

[0044] (3) Hot curing process: Turn on the high-pressure centrifuge or Roots blower of the air inlet pipe 1 to introduce the lime tail gas into the blower 4. By turning on the blower, the lime tail gas is transported to the air inlet pipe 5 and then to the bottom of the hot curing furnace. A raised perforated steel cap 9 is provided in the middle of the bottom of the furnace 8 to ensure that the lime tail gas passes evenly through the steel slag layer for hot curing and carbonization. This process continues to the upper part of the hot curing furnace, and the pressure inside the furnace is maintained at about 5000 Pa for 3 to 6 hours. Multiple air outlets are evenly arranged on one side of the upper edge of the hot curing furnace, and these air outlets are connected to the air outlet pipe 3. The air outlet pipe 3 is equipped with a pressure limiting valve 6. When the pressure inside the furnace exceeds 8000 Pa, the pressure limiting valve 6 will automatically open to release the excess gas, and the lime tail gas will re-enter the blower 4 through the circulation switch and continue the carbonization process through the air inlet pipe 5 again.

[0045] (4) End of operation: After the hot quenching process is completed, open the vent pipe 3 to vent the remaining lime tail gas in the furnace. Stop the blower 4, open the furnace cover 7, and lift the furnace chamber 8. When the temperature of the steel slag in the furnace drops to 50-80℃, use a crane to lift the furnace chamber containing the treated steel slag out to complete the entire treatment process.

[0046] This utility model provides a concept and method for a device for hot-quenching and carbonizing steel slag. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of this utility model. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principle of this utility model, and these improvements and modifications should also be considered within the scope of protection of this utility model. All components not explicitly stated in this embodiment can be implemented using existing technology.

Claims

1. An apparatus for hot autoclaving carbonated steel slag, characterized in that, It includes a hot-pressing oven, an air inlet pipe (1), an air inlet pipe (5), and an air outlet pipe (3); the air inlet pipe (1) is connected to the air inlet pipe (5), and the end of the air inlet pipe (5) extends into the hot-pressing oven; one end of the air outlet pipe (3) is connected to the top side of the hot-pressing oven, and the other end is connected to an external exhaust gas treatment unit; the middle part of the air outlet pipe (3) is reconnected to the air inlet pipe (1) through a branch pipe, so that the unreacted exhaust gas in the hot-pressing oven is sent back into the air inlet pipe (5) through the air inlet pipe (1); The hot-bake oven is equipped with a furnace chamber (8), and a perforated steel cap (9) with an inward protrusion is provided at the center of the bottom of the furnace chamber (8); the end of the air inlet pipe (5) extends into the perforated steel cap (9).

2. The apparatus for hot-quenching and carburizing steel slag according to claim 1, characterized in that, The bottom of the furnace liner (8) inside the hot-drying furnace is surrounded by a set of aluminum micro-casting (10) around the porous steel cap (9) to lift the furnace liner (8) so that it does not contact the bottom of the hot-drying furnace.

3. The apparatus for hot-quenching and carburizing steel slag according to claim 1, characterized in that, The hot oven has an opening at the top and is equipped with an oven cover (7) for opening and closing.

4. The apparatus for hot-quenching and carburizing steel slag according to claim 1, characterized in that, A pressure limiting valve (6) is installed inside the air outlet pipe (3).

5. The apparatus for hot-quenching and carburizing steel slag according to claim 1, characterized in that, A circulation switch (2) is installed in the branch pipe that connects the middle of the air outlet pipe (3) to the air inlet pipe (1).

6. The apparatus for hot-quenching and carburizing steel slag according to claim 1, characterized in that, The front end of the air inlet pipe (1) is connected to a high-pressure centrifuge or a Roots blower.

7. The apparatus for hot-quenching and carburizing steel slag according to claim 1, characterized in that, The hot oven has a set of air vents on the top side connected to the air vent pipe (3).

8. The apparatus for hot-quenching and carburizing steel slag according to claim 4, characterized in that, The pressure relief valve (6) is adjustable, with the limit being that it does not lift the furnace cover of the hot oven.

9. The apparatus for hot-quenching and carburizing steel slag according to claim 1, characterized in that, The top height of the porous steel cap (9) exceeds half the depth of the furnace liner (8).

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