Carbonized steel slag aggregate preparation device

Abstract

The utility model discloses a carbonized steel slag aggregate preparation device, and relates to the field of building material preparation and carbon capture. The device comprises a carbonization device, a flue gas discharge pipe, a flue gas inlet pipe, a rotary carrier roller, a flue gas distributor, a gas guide pipe, a distributing device and a feeding conveying belt, the feeding conveying belt is installed above one side of the carbonization device, the flue gas inlet pipe is installed below the other side of the carbonization device, the flue gas inlet pipe is communicated with the flue gas distributor, and the rotary carrier roller is communicated with the flue gas distributor. A smoke distributor is arranged in the carbonization device, a rotating carrier roller is arranged below the smoke distributor, a distributing device and a gas guide pipe are arranged in an inner cavity of the carbonization device, the distributing device is located at the discharging position of the feeding conveying belt, the gas guide pipe is located below the distributing device, and a smoke discharging pipe is arranged at the top of the carbonization device. The carbonization device has the beneficial effects that the carbonization device is simple in structure, convenient to operate and easy to realize, the double targets of large-scale absorption of the steel slag and carbon emission reduction are realized, and the prepared mortar steel slag aggregate can meet the requirement of large-scale absorption of the steel slag.

Description

Technical Field

[0001] The utility model relates to the fields of building material preparation and carbon capture, and in particular to a carbonized steel slag aggregate preparation device. Background Art

[0002] The steel industry produces a large amount of steel slag, accounting for about 10-20% of steel production. Many companies prepare steel slag powder for use as cement admixture. With the implementation of "GB175-2023 General Silicate", the sales of steel slag powder will be restricted, and using it as aggregate will become the main way to consume it on a large scale. The presence of f-CaO in steel slag has volume instability, which is the reason that affects its use as a building aggregate. The f-CaO in it is converted into CaCO by carbonization. 3 , in order to eliminate its instability, is the fundamental technical direction to solve the problem.

[0003] There are many related studies on the preparation of aggregates by carbonization of steel slag. The patent "A method for preparing carbonized steel slag lightweight aggregate and concrete containing carbonized steel slag lightweight aggregate" (CN202011468426.1) uses steel slag powder, vitrified microspheres, and quicklime as raw materials, and prepares lightweight aggregates by carbonization consolidation. The purpose is different from that of carbonizing granular steel slag to prepare aggregates. The patent "A carbonized steel slag artificial porous aggregate and its preparation method" (CN201910553298.1) uses steel slag powder, fly ash, and cement as raw materials, and consolidates the powdered materials by carbonization to prepare aggregates. The purpose is also different from that of carbonizing granular steel slag to eliminate the hazards of f-CaO. Both of the above patents use pure CO 2 It is a carbonization gas source and has poor economic efficiency. The patent "A method for preparing auxiliary cementitious materials and concrete products by carbonizing steel slag using industrial furnace tail gas" (CN202310759843.9) involves carbonization of granular steel slag, steel slag-based carbonized cementitious materials, and carbonization of products. Granular steel slag is carbonized with the addition of a carbonization auxiliary agent, and the carbonization auxiliary agent is a mixture of 99% water, 0-0.5% carbonization surfactant, and 0-0.5% water reducer; the water reducer is one or a combination of any two of lignin sulfonates, polycyclic aromatic salts, and water-soluble resin sulfonates; the carbonization surfactant is one or a combination of any two of hydrophilic carboxylates, sulfates, quaternary ammonium salts, PEO derivatives, and lactones. From the perspective of composition, the main function of the carbonization accelerator is to maintain the moisture inside the steel slag when the temperature of the carbonization gas is high, and does not involve the technical factor of increasing the dissolution of calcium ions to promote carbonization. The patent "A method for accelerating the microbial mineralization of alkaline solid waste" (CN201710062691.1) adds carbonic anhydrase bacterial solution to alkaline solid waste and performs carbonization curing in a carbonization pressure autoclave to improve the strength and durability of the product.

[0004] The paper "The role and mechanism of microorganisms in improving the stability and strength of steel slag cementitious materials" (Bulletin of the Chinese Silicate Society, 2022, 39(8): 2363-2371) adds microorganisms during the use of steel slag powder to accelerate carbonization and reduce the linear expansion rate of the sample during autoclave carbonization. The carbonization is carried out in a carbonization kettle with 4% microorganisms added. After 4 hours, the f-CaO conversion rate can reach 97%. The degree of technical practicality is relatively low.

[0005] Analysis of the literature found that the technologies described in the existing patents and literature have the following problems: ① Accelerating carbonization. Only patent CN202310759843.9 promotes carbonization from the perspective of water retention, but does not involve how to promote the dissolution of calcium ions in steel slag and the release of CO in the gaseous state. 2 ②Use microbial enzymes to accelerate the dissolution of CO 2 To CO 3 2- ③ Because the acceleration technology has not been solved, many patents use high pressure and pure CO 2 ④ Lack of practical equipment. Only patent CN202310759843.9 adopts a multi-layer belt carbonization device, but the equipment structure is still relatively complex. These problems affect the industrialization of steel slag carbonization technology.

[0006] Premixed mortar is a major building material product that the country encourages to develop, and the demand is large. Mortar production requires a large amount of fine aggregate. The preparation of mortar aggregate with steel slag is an encouraged direction for the comprehensive utilization of steel slag, and the country has formulated corresponding technical standards. The pressure steam stability in the standard is related to the f-CaO content. Only by reducing the f-CaO content through carbonization can the steel slag with qualified particle size meet the use requirements.

[0007] Rapid carbonization and efficient equipment are the core issues of the industrialization of steel slag carbonization for aggregate preparation. The two are interrelated. The faster the carbonization speed, the shorter the carbonization time, the simpler the equipment, and the easier it is to achieve in industry. The key issue of rapid carbonization is how to promote the conversion of f-CaO in steel slag to Ca 2+ The conversion of CO in flue gas 2 To CO 3 2- The key issues of high-efficiency equipment are simple equipment structure, high mass transfer efficiency and simple process parameter control. The utility model intends to solve the above two key issues to promote the industrialization of preparing aggregates from industrial flue gas carbonized granulated steel slag and realize the coupling of comprehensive utilization of steel slag and carbon capture. Utility Model Content

[0008] The utility model aims to provide a carbonized steel slag aggregate preparation device to address the shortcomings and defects of the prior art, and to add an alkaline calcium ion chelating agent to promote the conversion of f-CaO to Ca 2+ The conversion of CO in flue gas 2 To CO 3 2- Adding alkaline calcium ion chelating agent can accelerate the conversion of f-CaO to Ca 2+ The conversion of CO 2 To CO 3 2- The conversion of EDTA is recycled and has the function of a catalyst. It accelerates carbonization, shortens the time required for carbonization, reduces the volume of carbonization equipment, simplifies the equipment structure; it also reduces the material layer height and the pressure loss of carbonization gas, thereby reducing the slag particle size and increasing the mass transfer efficiency. The carbonization device has a simple structure, convenient operation, and is easy to implement. The dual goals of large-scale consumption of slag and carbon emission reduction are achieved, and the prepared mortar slag aggregate can meet the needs of large-scale consumption of slag.

[0009] To achieve the above-mentioned purpose, the utility model adopts the following technical scheme: a carbonized steel slag aggregate preparation device, which includes a carbonization device, a smoke exhaust pipe 1, a smoke inlet pipe 3, a rotating roller 4, a smoke distributor 5, an air duct 6, a distributor 7, and a feeding conveyor belt 8. The feeding conveyor belt 8 is installed above one side of the carbonization device, and the smoke inlet pipe 3 is installed below the other side of the carbonization device. The smoke inlet pipe 3 is connected to the smoke distributor 5, and a rotating roller 4 is installed below the smoke distributor 5. The inner cavity of the carbonization device is installed with a distributor 7 and an air duct 6. The distributor 7 is located at the discharge point of the feeding conveyor belt 8, and the air duct 6 is located below the distributor 7. The smoke exhaust pipe 1 is installed on the top of the carbonization device.

[0010] Furthermore, a smoke return pipe 2 is installed between the smoke exhaust pipe 1 and the smoke inlet pipe 3 .

[0011] Furthermore, the cross section of the distributor 7 is in the shape of a human figure.

[0012] Furthermore, at least two rotating rollers 4 are provided, and both are horizontally arranged at the lower side of the inner cavity of the carbonization device.

[0013] After adopting the above technical solution, the beneficial effects of the utility model are: the preparation device has at least the following advantages:

[0014] 1) Add alkaline calcium ion chelating agent to promote f-CaO to Ca 2+ The conversion of CO in flue gas 2 To CO 3 2-The catalytic principle is as follows:

[0015] CaO+EDTA+H 2 O=CaY+2NaOH

[0016] CO 2 +H 2 O=CO 3 2- +2H +

[0017] CaY+2Na++CO 3 2- =CaCO 3 ↓+EDTA

[0018] 2) Adding alkaline calcium ion chelating agent can accelerate the conversion of f-CaO to Ca 2+ The conversion of CO 2 To CO 3 2- The EDTA is recycled and acts as a catalyst.

[0019] 3) Accelerate carbonization, shorten the time required for carbonization, reduce the volume of carbonization equipment, and simplify the equipment structure; it also reduces the material layer height and the pressure loss of carbonization gas, thereby reducing the slag particle size and increasing the mass transfer efficiency.

[0020] 4) The carbonization device has a simple structure, is easy to operate and easy to implement.

[0021] 5) The dual goals of large-scale disposal of steel slag and carbon emission reduction have been achieved, and the prepared mortar steel slag aggregate can meet the needs of large-scale disposal of steel slag. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0023] Figure 1 It is a structural schematic diagram of the utility model.

[0024] Figure 2 It is a preparation flow chart in the utility model.

[0025] Figure 3 It is a schematic diagram of the flue gas distributor of the carbonization device in the utility model.

[0026] Figure 4 This is a diagram showing the effect of the use of a carbonization accelerator on the free calcium oxide content in steel slag during carbonization in the utility model (in the diagram: the steel slag particle size is 5-20 mm, the carbonization temperature is 80°C, the CO2 concentration is 20%, the accelerating carbonization agent is sodium ethylenediaminetetraacetate, the dosage is 0.20% of the steel slag mass, and the steel slag moisture is 12%).

[0027] Explanation of the reference numerals: smoke exhaust pipe 1, smoke return pipe 2, smoke inlet pipe 3, rotating roller 4, smoke distributor 5, air guide pipe 6, distributor 7, feed conveyor belt 8. DETAILED DESCRIPTION

[0028] See also Figure 1-Figure 4 As shown, the technical solution adopted in this specific embodiment is: it includes a carbonization device, a smoke exhaust pipe 1, a smoke inlet pipe 3, a rotating roller 4, a smoke distributor 5, an air duct 6, a distributor 7, and a feeding conveyor belt 8. The feeding conveyor belt 8 is installed above one side of the carbonization device, and the smoke inlet pipe 3 is installed below the other side of the carbonization device. The smoke inlet pipe 3 is connected to the smoke distributor 5, and a rotating roller 4 is installed below the smoke distributor 5. The inner cavity of the carbonization device is installed with a distributor 7 and an air duct 6. The distributor 7 is located at the discharge point of the feeding conveyor belt 8, and the air duct 6 is located below the distributor 7. The smoke exhaust pipe 1 is installed on the top of the carbonization device.

[0029] More specifically, a flue gas return pipe 2 is installed between the flue gas exhaust pipe 1 and the flue gas inlet pipe 3. If the flue gas discharged from the flue gas exhaust pipe 1 at the top of the carbonization device has a high carbon dioxide concentration, it is collected through the flue gas return pipe 2 and returned to the bottom of the carbonization device for recycling to improve the carbon capture rate.

[0030] More specifically, the cross section of the distributor 7 is in the shape of a human figure. The granular slag can be divided into two parts by the distributor 7 in the shape of a human figure, and the air guide pipe 6 located below the distributor 7 can be secured.

[0031] More specifically, at least two rotating rollers 4 are provided, and both are horizontally arranged at the lower side of the inner cavity of the carbonization device. The discharge speed and carbonization time of the slag are controlled by controlling the rotation speed of the rotating rollers 4.

[0032] The working principle of the utility model is as follows: granular steel slag enters from the feed conveyor belt 8 and is fed into the "herringbone" distributor 7 through the feed conveyor belt 8; after carbonization, the steel slag is discharged from the bottom, and the steel slag column is supported by the rotating roller 4 at the bottom of the device. The discharge speed and carbonization time of the steel slag are controlled by controlling the rotation speed of the rotating roller 4; the industrial smoke enters from the smoke inlet pipe 3 and is discharged from the top of the smoke exhaust pipe 1, and the carbonized air flow is evenly distributed in the material column through the central air guide pipe 6 and the bottom smoke distributor 5; the carbonization device In the process of preparation, the industrial flue gas and the granular steel slag move in the opposite direction. During the preparation, the staff should first crush and screen the steel slag after iron selection, and take the steel slag particles with a particle size between 5 and 20 mm for carbonization; then spray the carbonization accelerator solution on the granular steel slag, and then age the steel slag at room temperature for 24 hours; after aging, the granular steel slag enters the carbonization device from the feeding conveyor belt 8, and the industrial flue gas rich in carbon dioxide is used as the carbonization gas source. The industrial flue gas enters from the flue gas inlet pipe 3 and is discharged from the top; the steel slag is discharged from the top of the device The slag enters the carbonization device and is discharged from the bottom after carbonization; after the slag is carbonized for 0.5 to 2.0 hours in the carbonization device, it is discharged from the carbonization device to obtain carbonized slag aggregate; the carbonized slag is further crushed and screened, and the 0.074 to 2.36 mm portion can be used as mortar aggregate, and the portion less than 0.074 mm can be used to prepare slag powder to achieve full particle size utilization, wherein the slag carbonization accelerator is an alkaline calcium ion complexing agent of sodium ethylenediaminetetraethyl and sodium citrate; the mass fraction of the carbonization accelerator is 0% of the mass of the slag .06~0.30%; after spraying the carbonization accelerator, the moisture content of the steel slag is 10~15%, and industrial flue gas is used, and the flue gas is used for carbonization after waste heat utilization, the temperature is 60~90℃, and carbonization is carried out at the natural temperature of the flue gas, and the relative humidity in the carbonization device is 70-95%, and the relative humidity value is ensured by refluxing the waste flue gas discharged from the carbonization device. The thickness of the granular steel slag layer in the carbonization device is 3~6m, and the height of the layer is adjusted according to the principle that the height increases with the increase of the average particle size of the steel slag.

[0033] The above description is only used to illustrate the technical solution of the utility model rather than to limit it. Other modifications or equivalent substitutions made to the technical solution of the utility model by ordinary technicians in this field should be included in the scope of the claims of the utility model as long as they do not depart from the spirit and scope of the technical solution of the utility model.

Claims

1. A carbonized steel slag aggregate preparation device, characterized in that: It comprises a carbonization device, a smoke exhaust pipe (1), a smoke intake pipe (3), a rotating roller (4), a smoke distributor (5), an air guide pipe (6), a distributor (7), and a feeding conveyor belt (8). The feeding conveyor belt (8) is installed above one side of the carbonization device, and the smoke intake pipe (3) is installed below the other side of the carbonization device. The smoke intake pipe (3) is connected to the smoke distributor (5), and a rotating roller (4) is installed below the smoke distributor (5). The inner cavity of the carbonization device is installed with a distributor (7) and an air guide pipe (6). The distributor (7) is located at the discharge point of the feeding conveyor belt (8), and the air guide pipe (6) is located below the distributor (7). The top of the carbonization device is installed with a smoke exhaust pipe (1).

2. The carbonized steel slag aggregate preparation device according to claim 1, characterized in that: A smoke return pipe (2) is installed between the smoke exhaust pipe (1) and the smoke inlet pipe (3).

3. The carbonized steel slag aggregate preparation device according to claim 1, characterized in that: The cross section of the distributor (7) is in the shape of a human figure.

4. The carbonized steel slag aggregate preparation device according to claim 1, characterized in that: At least two rotating rollers (4) are provided, and both are horizontally arranged at the lower side of the inner cavity of the carbonization device.

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