Preparation method for improving performance and carbon sequestration rate of steel slag carbonized product

Abstract

The invention provides a preparation method for improving the performance and carbon sequestration rate of a steel slag carbonized product, and the preparation method specifically comprises the following steps: (1) weighing the following raw materials in percentage by mass: 50-100 parts of steel slag powder, 13-17 parts of deionized water and 1 part of alcohol amine; (2) mixing the weighed deionized water with alcohol amine to obtain an alcohol amine solution, stirring the alcohol amine solution in a magnetic stirrer, continuously introducing CO2 gas with the concentration of 99.9% to carbonate the alcohol amine solution, and controlling the gas introduction time to be 2 hours; (3) doping an alkylol amine solution subjected to carbonation treatment into the weighed steel slag powder, and uniformly stirring by using a neat paste stirrer; (4) pressing the steel slag mixture into steel slag product briquettes in a compression molding manner; and (5) putting the briquette into a carbonization kettle, and introducing CO2 gas with the purity of 99.9% to prepare a steel slag carbonized product. The problem that the interior of the steel slag carbonized product cannot be fully carbonated and maintained is solved, so that the comprehensive performance and the carbon sequestration rate of the steel slag carbonized product are remarkably improved.

Description

Technical Field

[0001] The present invention relates to the field of carbonization and utilization of industrial waste slag and the technical field of "double carbon", and in particular to a preparation method for improving the performance and carbon fixation rate of carbonized steel slag products. Background Art

[0002] With the advancement of global industrial production and the acceleration of urbanization, CO2 emissions have increased rapidly, leading to a series of problems such as global warming and rising sea levels.

[0003] Steel slag is an alkaline industrial by-product produced during the steelmaking process. According to different production processes, steel slag is divided into alkaline oxidation furnace slag, electric arc furnace slag and ladle slag. According to statistics, China's steel slag production in 2022 will be 1.017 billion tons, accounting for 53.99% of the world's annual production, and China's steel slag production in 2023 will be 1.019 billion tons, accounting for 53.97% of the world's annual production. In addition, there are still a large number of abandoned steel slag piled up on site, which not only occupies a large area of ​​land, but also produces alkaline leachate to pollute nearby waters and lakes, seriously affecting the local ecological environment.

[0004] The chemical composition of steel slag mainly includes CaO, Al2O3, Fe2O3 and other components, among which the Ca content is relatively high and the pH value is also relatively large, which determines that steel slag has good adaptability to carbonation treatment. Treating steel slag through semi-dry carbonation process can effectively realize the storage of CO2 and promote the rapid digestion of free CaO and MgO, thereby effectively improving the stability of steel slag. However, there is still a large amount of uncarbonated steel slag inside the steel slag products after semi-dry carbonation curing, which leads to certain defects in the stability of carbonated steel slag products. In view of this, solving the stability problem of steel slag carbonization products has become a top priority. Carbonation treatment technology can significantly improve the strength of steel slag products in a relatively short period of time, effectively solve the problem of low early strength caused by insufficient hydration activity of steel slag, and eliminate the stability problem to a certain extent. In addition, the carbonation process can also neutralize the pH value of steel slag, reduce the leaching of harmful elements, and thus reduce the adverse impact on the environment. However, given the complexity of steel slag composition and the fact that CaCO3 generated during carbonation curing may clog the surface pores of steel slag products, the interior of the steel slag is difficult to be fully carbonated. This results in the carbonization rate and strength of steel slag carbonized products not reaching the ideal level. This technical defect is a key issue that needs to be overcome in the current application of steel slag carbonation. Summary of the invention

[0005] In view of the defects of low compressive strength and low carbonization rate of carbonized steel slag products in the prior art, the present invention provides a preparation method for improving the performance and carbon fixation rate of carbonized steel slag products.

[0006] The technical means adopted by the present invention are as follows:

[0007] A preparation method for improving the performance and carbon fixation rate of steel slag carbonized products, specifically comprising the following steps:

[0008] (1) Calculate the following raw materials by mass percentage: 80-100 parts of steel slag powder, 13-17 parts of deionized water, and 1 part of alcoholamine;

[0009] (2) weighing deionized water and ethanolamine to form an ethanolamine solution, placing it in a magnetic stirrer for stirring, and then continuously introducing 99.9% CO2 gas to carbonate the ethanolamine solution, and the ventilation time is controlled at 2 hours;

[0010] (3) Add the carbonation-treated alcohol amine solution to the weighed steel slag powder and mix it with a slurry mixer until it is uniform;

[0011] (4) pressing the steel slag slurry into a steel slag product block by a pressing molding method;

[0012] (5) The steel slag product blocks are placed in a carbonization kettle, and CO2 gas with a purity of 99.9% is introduced to make steel slag carbonized products.

[0013] Furthermore, the raw materials weighed in step (1) also include 10-20 parts of lithium slag powder; in step (3), the alcohol amine solution after carbonation treatment is added to the weighed steel slag powder and lithium slag powder.

[0014] Furthermore, the steel slag powder in step (1) is any one of converter steel slag, open-hearth steel slag and electric furnace steel slag.

[0015] Furthermore, the alcoholamine in step (1) is any one of monoethanolamine, diethanolamine and triethanolamine.

[0016] Furthermore, in step (2), the stirring temperature of the magnetic stirrer is 40-60° C., and the stirring rate is 100 r / min.

[0017] Furthermore, in step (4), the pressure of the pressing process is 6-10 MPa, and the pressure is maintained for 30 seconds.

[0018] Furthermore, in step (5), the pressure in the carbonization kettle is 0.1-0.3 MPa, and the carbonization time is 2 h.

[0019] The mechanism of the method of the present invention for improving the performance and carbon fixation rate of steel slag carbonization products is that steel slag is rich in a variety of calcium-containing minerals, mainly including C3S, C2S, C4AF, and free CaO and MgO. These minerals themselves have a high carbon fixation capacity. Under appropriate carbonization conditions, CO2 can react with free CaO, MgO, C3S, C2S and Ca in the hydration product CSH to form a carbonization product.2+ Mg 2+ The present invention introduces different types of alcoholamines (such as monoethanolamine and triethanolamine) as additives based on the mechanism of carbonization reaction. Alcoholamines have good complexing properties and can complex Ca in the system. 2+ , thereby increasing Ca 2+ The leaching rate of the alkanoic acid amine can be increased, and the carbonation reaction of the calcium-containing minerals can be accelerated. In addition, the amino group in the alkanoic acid amine molecule can react with CO2 to generate a stable carbamate. Under certain temperature conditions, the carbamate can desorb and release CO2, and regenerate the alkanoic acid amine. Based on this, the present invention proposes a method for preparing a carbonized steel slag product with internal and external synergistic carbonization, wherein an alkanoic acid amine solution rich in CO2 is used as the internal CO2 source of the product, and the heat released by the carbonation reaction is used to stimulate the desorption of the alkanoic acid amine in the steel slag product, thereby promoting the release of CO2 and realizing the carbonation maintenance inside the steel slag. In addition, the alkanoic acid amine itself can also be used as a catalyst to accelerate the hydration and carbonation reaction of the steel slag, thereby effectively improving the performance and carbon fixation efficiency of the steel slag carbonized product.

[0020] At the same time, in view of the problem that the volume stability risk of steel slag carbonized products cannot be fundamentally eliminated due to insufficient internal carbonization, the present invention incorporates 10-20 parts of lithium slag as an auxiliary material in the preparation process of steel slag billets, and adopts a pressure steaming method to perform a stability test. The results show that the stability problem of steel slag carbonized products has been significantly improved, which is mainly due to the chemical stability of lithium slag. The main components of lithium slag include crystalline SiO2 and Al2O3, and the reaction activity is relatively low. When lithium slag is incorporated into steel slag products, it acts as an inert filling material and has a good dispersing and diluting effect on free CaO and free MgO in steel slag products. These two components are the key factors that lead to poor volume stability of steel slag carbonized products. The incorporation of lithium slag can effectively reduce the proportion of these unstable components, thereby significantly improving the volume stability of steel slag carbonized products.

[0021] Compared with the prior art, the present invention has the following advantages:

[0022] 1. The preparation method for improving the performance and carbon fixation rate of carbonized steel slag products provided by the present invention introduces CO2-rich alcohol amines and proposes material and process designs for internal and external coordinated carbonization, which effectively solves the problem that the internal of carbonized steel slag products is difficult to fully carbonate during the carbonation curing process. The carbon fixation rate can reach up to 10.47%, which is 15.8% higher than that of the control group.

[0023] 2. The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided by the present invention significantly improves the comprehensive performance of steel slag carbonized products. The compressive strength of the products can reach up to 68.31 MPa, which is 18.8% higher than that of the control group. At the same time, the CO2-rich amine solution makes the steel slag carbonized products denser and significantly reduces the proportion of internal harmful pores. The present invention provides a new theoretical basis for the efficient utilization of waste slag such as steel slag and lithium slag, and broadens the application prospects of carbonation maintenance in the construction industry.

[0024] 3. The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided by the present invention further thoroughly solves the poor stability problem of steel slag products by adding lithium slag. The stability of steel slag / lithium slag carbonized products tested by the pressure steaming method is good.

[0025] 4. The preparation method for improving the performance and carbon fixation rate of steel slag carbonization products provided by the present invention uses only steel slag, lithium slag, deionized water, alcohol amine, and carbon dioxide gas as raw materials, wherein steel slag and lithium slag are both industrial waste residues, and carbon dioxide is a greenhouse gas. The raw materials are simple and easy to obtain, the process is simple and easy to operate, and does not involve the use of large-scale instruments and equipment.

[0026] Based on the above reasons, the present invention can be widely promoted in the fields of waste slag carbonization utilization and "double carbon". BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required to be used in the description of the embodiments or the prior art are briefly introduced below.

[0028] Figure 1 This is a flow chart of the alcohol amine solution loading CO2 according to the present invention.

[0029] Figure 2 The present invention is a flow chart of the preparation method for improving the performance and carbon fixation rate of steel slag carbonized products. DETAILED DESCRIPTION

[0030] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0031] like Figure 1-2As shown, the present invention provides a preparation method for improving the performance and carbon fixation rate of steel slag carbonized products, which specifically comprises the following steps:

[0032] (1) Calculate the following raw materials by mass percentage: 80-100 parts of steel slag powder, 13-17 parts of deionized water, and 1 part of alcoholamine;

[0033] (2) weighing deionized water and ethanolamine to form an ethanolamine solution, placing it in a magnetic stirrer for stirring, and then continuously introducing 99.9% CO2 gas to carbonate the ethanolamine solution, and the ventilation time is controlled at 2 hours;

[0034] (3) Add the carbonation-treated alcohol amine solution to the weighed steel slag powder and mix it with a slurry mixer until it is uniform;

[0035] (4) pressing the steel slag mixture into a steel slag product block by a pressing method; the size of the steel slag product block is 40 mm×40 mm×40 mm;

[0036] (5) The steel slag product blocks are placed in a carbonization kettle, and CO2 gas with a purity of 99.9% is introduced to make steel slag carbonized products.

[0037] Furthermore, the raw materials weighed in step (1) also include 10-20 parts of lithium slag powder; in step (3), the alcohol amine solution after carbonation treatment is added to the weighed steel slag powder and lithium slag powder.

[0038] Furthermore, the steel slag powder in step (1) is any one of converter steel slag, open-hearth steel slag and electric furnace steel slag.

[0039] Furthermore, the alcoholamine in step (1) is any one of monoethanolamine, diethanolamine and triethanolamine.

[0040] Furthermore, in step (2), the stirring temperature of the magnetic stirrer is 40-60° C., and the stirring rate is 100 r / min.

[0041] Furthermore, in step (2), 99.9% CO2 gas is first introduced into a container containing a hydrochloric acid solution and then introduced into the alcoholamine solution, in order to prevent the CO2 gas from directly introducing the alcoholamine solution and taking away the moisture in the solution.

[0042] Furthermore, in step (4), the pressure of the pressing process is 6-10 MPa, and the pressure is maintained for 30 seconds.

[0043] Furthermore, in step (5), the pressure in the carbonization kettle is 0.1-0.3 MPa, and the carbonization time is 2 h.

[0044] Example 1

[0045] The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided in this embodiment specifically comprises the following steps:

[0046] (1) Calculate the following raw materials by mass percentage: 100 parts of steel slag powder, 13 parts of deionized water, and 1 part of monoethanolamine;

[0047] (2) 13 parts of weighed deionized water and 1 part of monoethanolamine were mixed to form a monoethanolamine solution, the prepared monoethanolamine solution was placed in a magnetic stirrer, and the monoethanolamine solution was stirred at a temperature of 50° C. and a speed of 100 r / min, and then CO2 gas with a concentration of 99.9% was continuously introduced to carbonate the monoethanolamine solution, and the ventilation time was controlled at 2 h;

[0048] (3) Adding the carbonation-treated monoethanolamine solution to the weighed steel slag powder, stirring the mixture in a slurry mixer at a speed of 60 r / min for 3 min, and then stirring the mixture at a speed of 120 r / min for 5 min until the mixture is uniform;

[0049] (4) The uniformly mixed steel slag mixture is placed in a 40 mm × 40 mm × 40 mm steel mold, and then placed on a press to press and shape it. After pressing and shaping at 8 MPa, the load is maintained for 30 seconds;

[0050] (5) The steel slag product block is placed in a carbonizing kettle, and CO2 gas with a purity of 99.9% is introduced. The pressure in the carbonizing kettle is maintained at 0.2 MPa. The carbonization is carried out for 2 hours to produce a carbonized steel slag product. After the carbonization is completed, the increased weight of the carbonized steel slag product is weighed to calculate the carbon fixation rate of the steel slag.

[0051] Example 2

[0052] The preparation method for improving the performance and carbon fixation rate of carbonized steel slag products provided in this embodiment is different from that in Embodiment 1 only in that the alcoholamine in step (1) is diethanolamine.

[0053] Example 3

[0054] The preparation method for improving the performance and carbon fixation rate of carbonized steel slag products provided in this embodiment is different from that in Embodiment 1 only in that the alcoholamine in step (1) is triethanolamine.

[0055] Example 4

[0056] The preparation method for improving the performance and carbon fixation rate of carbonized steel slag products provided in this embodiment is different from that in Embodiment 1 only in that the stirring temperature of the magnetic stirrer in step (2) is 40°C.

[0057] Example 5

[0058] The preparation method for improving the performance and carbon fixation rate of carbonized steel slag products provided in this embodiment is different from that in Embodiment 1 only in that the stirring temperature of the magnetic stirrer in step (2) is 60°C.

[0059] Example 6

[0060] The preparation method for improving the performance and carbon fixation rate of carbonized steel slag products provided in this embodiment is different from that in Example 1 only in that the molding pressure in step (4) is controlled to be 6 MPa.

[0061] Example 7

[0062] The preparation method for improving the performance and carbon fixation rate of carbonized steel slag products provided in this embodiment is different from that in Embodiment 1 only in that the molding pressure in step (4) is controlled to be 10 MPa.

[0063] Example 8

[0064] The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided in this embodiment is different from that in Example 1 only in that the pressure in the carbonization kettle in step (5) is maintained at 0.1 MPa.

[0065] Example 9

[0066] The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided in this embodiment is different from that in Example 1 only in that the pressure in the carbonization kettle in step (5) is maintained at 0.3 MPa.

[0067] Comparative Example 1

[0068] The preparation method of the steel slag carbonized product adopted in Comparative Example 1 specifically comprises the following steps:

[0069] (1) Calculate the following raw materials by mass percentage: 100 parts of steel slag powder and 13 parts of deionized water;

[0070] (2) Add weighed deionized water to the weighed steel slag powder, stir in a slurry mixer at a speed of 60 r / min for 3 min, then at a speed of 120 r / min for 5 min, until the mixture is uniform;

[0071] (3) The uniformly mixed steel slag mixture is placed in a 40mm×40mm×40mm steel mold, and then placed on a press to press and form it. After pressing and forming at 8MPa, the load is maintained for 30s; (4) The steel slag product block is placed in a carbonization kettle, and CO2 gas with a purity of 99.9% is introduced. The pressure in the carbonization kettle is maintained at 0.2MPa. Carbonization is carried out for 2h to make a carbonized steel slag product. After the carbonization is completed, the increased weight of the steel slag carbonized product is weighed to calculate the carbon fixation rate of the steel slag.

[0072] Example 10

[0073] The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided in this embodiment specifically comprises the following steps:

[0074] (1) Calculate by mass percentage the following raw materials: 90 parts of steel slag powder, 10 parts of lithium slag powder, 17 parts of deionized water (to increase the water-solid ratio to meet the requirements of slurry pressing and molding), and 1 part of monoethanolamine;

[0075] (2) 17 parts of weighed deionized water and 1 part of monoethanolamine were mixed to form a monoethanolamine solution, the prepared monoethanolamine solution was placed in a magnetic stirrer, and the monoethanolamine solution was stirred at a temperature of 50° C. and a speed of 100 r / min, and then CO2 gas with a concentration of 99.9% was continuously introduced to carbonate the monoethanolamine solution, and the ventilation time was controlled at 2 h;

[0076] (3) adding the carbonation-treated monoethanolamine solution to the weighed steel slag powder and lithium slag powder, stirring the mixture in a pure slurry mixer at a speed of 60 r / min for 3 min, and then stirring the mixture at a speed of 120 r / min for 5 min until the mixture is uniform;

[0077] (4) The uniformly mixed steel slag mixture is placed in a 40 mm × 40 mm × 40 mm steel mold, and then placed on a press to press and shape it. After pressing and shaping at 8 MPa, the load is maintained for 30 seconds;

[0078] (5) The steel slag product block is placed in a carbonization kettle, and CO2 gas with a purity of 99.9% is introduced. The pressure in the carbonization kettle is maintained at 0.2 MPa. The carbonization is carried out for 2 hours to make a steel slag carbonized product. After the carbonization is completed, the increased weight of the steel slag carbonized product is weighed to calculate the carbon fixation rate of the steel slag.

[0079] Embodiment 11

[0080] The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided in this embodiment is different from that in Example 10 only in that the raw materials weighed in step (1) include 85 parts of steel slag powder, 15 parts of lithium slag powder, 17 parts of deionized water, and 1 part of monoethanolamine.

[0081] Example 12

[0082] The preparation method for improving the performance and carbon fixation rate of steel slag carbonized products provided in this embodiment is different from that in Example 10 only in that the raw materials weighed in step (1) include 80 parts of steel slag powder, 20 parts of lithium slag powder, 17 parts of deionized water, and 1 part of monoethanolamine.

[0083] The compressive strength of the carbonized steel slag products obtained in Examples 1-13 and Comparative Example 1 and the results of the carbon fixation rate of the steel slag are shown in Table 1 below:

[0084] Table 1 Performance parameters of steel slag carbonized products

[0085] serial number Carbon fixation rate of steel slag (%) Compressive strength(MPa) Comparative Example 1 9.04 57.70 Example 1 10.47 68.31 Example 2 10.32 63.24 Example 3 10.38 65.38 Example 4 10.37 66.43 Example 5 10.35 66.17 Example 6 10.51 61.43 Example 7 10.37 67.89 Example 8 9.71 61.13 Example 9 10.48 68.78 Example 10 9.43 63.71 Embodiment 11 9.31 62.14 Example 12 9.06 60.50

[0086] Internal samples of the steel slag carbonized products obtained in Examples 1-3 and Comparative Example 1 were taken for mercury intrusion testing. The test results are shown in Table 2 below.

[0087] Table 2 Cumulative pore volume (mL / g)

[0088] serial number ≤10nm 10nm~50nm 50nm~100nm 100nm~10μm ≥10μm Comparative Example 1 0.21375 0.65315 0.30518 0.9663 0.10043 Example 1 0.2316 0.71024 0.31676 0.887 0.05725 Example 2 0.2419 0.68122 0.31639 0.9012 0.07472 Example 3 0.3143 0.73801 0.32333 0.9151 0.06808

[0089] The steel slag carbonized products obtained in Example 1 and Examples 10-12 were placed in an autoclave, and the autoclave was heated to 190°C at a pressure of 3 MPa for 3 hours. After being taken out, they were cooled to room temperature, and their dimensional changes were measured with a screw micrometer. The specific change values ​​are shown in Table 3 below.

[0090] Table 3 Dimensional changes of steel slag carbonized products (mm)

[0091] serial number Dimensions before autoclaving (mm) Dimensions after autoclaving (mm) Difference(mm) Example 1 20.43 20.46 0.03 Example 10 20.33 20.34 0.01 Embodiment 11 20.04 20.04 0 Example 12 20.01 20.01 0

[0092] According to the data analysis of Examples 1-3 and Comparative Example 1 in Table 1, compared with pure steel slag powder, after adding 1 part of alcoholamine (monoethanolamine, diethanolamine, triethanolamine), the compressive strength of steel slag carbonized products increased by 18.8%, 9.6% and 13.4%, respectively, and the carbon fixation rate increased by 15.8%, 14.2% and 14.8%, respectively; This shows that the three CO2-rich alcoholamines play a catalytic role in the carbonation reaction of steel slag and promote the carbonation process of steel slag; Among them, Example 1 shows the best effect, indicating that monoethanolamine has the best catalytic performance. According to the results of Example 1 and Example 4-5, 50°C is the optimal stirring temperature of the alcoholamine solution. When the temperature is 40°C, the compressive strength of the steel slag carbonized product decreases by 2.75%, mainly because the lower temperature cannot provide enough energy for the alcoholamine to absorb CO2, resulting in incomplete reaction. When the temperature is 60°C, the compressive strength of the carbonized slag product decreases by 3.13%, which is due to the premature desorption of CO2 by the CO2-rich alcoholamine solution caused by the high temperature. According to the data of Example 1 and Examples 6-9, 8MPa is the optimal molding pressure for the carbonized slag product, and a carbonization pressure of 0.2MPa can achieve full carbonization of the carbonized slag product.

[0093] In Examples 10-12, based on the raw material ratio of Example 1, 10%, 15% and 20% lithium slag were added respectively. The addition of lithium slag significantly reduced the proportion of calcium-containing minerals, thereby affecting the generation of calcium carbonate and the formation of a dense calcium carbonate network structure, resulting in a decrease in compressive strength but still better than Example 1. At the same time, the addition of lithium slag provided a new channel for the diffusion of CO2, significantly improving the carbonization depth of the slag products. With the addition of lithium slag, the relative reduction in the slag content and the significant increase in the carbonization depth acted together, resulting in a slight decrease in the carbonization rate of the carbonized slag products, which was still better than Example 1. At the same time, the carbonization rate and compressive strength of Examples 1-6 were higher than those of Example 1, indicating that the CO2-rich alcoholamine solution did improve the carbonization rate and compressive strength of the carbonized slag products.

[0094] According to the data analysis of Examples 1-3 in Table 2: In order to clearly reveal the evolution law of the pore volume distribution of the material, the present invention has carried out a detailed classification of the pore structure and divided it into the following five categories: gel pores (≤10nm), fine capillary pores (10nm-50nm), medium capillary pores (50nm-100nm), large capillary pores (100nm-10μm) and macropores (≥10μm). It is worth noting that the increase in the number of large capillary pores and macropores often means that there are more harmful pores in the material; It can be observed from the data in Table 2 that after the addition of three CO2-containing alcoholamines, the The harmful pores are effectively controlled, which shows that ethanolamine can carry CO2 deep into the interior of steel slag products, release CO2 during the desorption process, and then react with calcium-containing minerals in the steel slag to form calcium carbonate (CaCO3); the newly generated calcium carbonate is tightly combined with hydration products such as CSH, filling the internal pores of the steel slag carbonized product, thereby reducing the proportion of harmful pores and significantly enhancing the mechanical properties of the steel slag carbonized product; and in Example 1, the addition of monoethanolamine shows the best carbon fixation effect, and the proportion of harmful pores is the lowest; the above test results verify the effectiveness of the internal and external synergistic carbonization mechanism proposed in the present invention.

[0095] As shown in Table 3, the dimensional change rate of the specimens without lithium slag addition after autoclaving treatment exceeded 0.1%, indicating that the volume stability of such steel slag carbonized products failed to meet the standard requirements; however, after introducing 10% lithium slag into the batch, the dimensional change rate of the specimens was reduced to below 0.1%; and when the lithium slag addition was further increased to 15%, the specimens showed almost no dimensional change after autoclaving treatment. This phenomenon fully proves that the addition of lithium slag has a significant effect on improving the volume stability of steel slag carbonized products, and further proves the important role of lithium slag in optimizing the performance of steel slag carbonized products, and 15% lithium slag addition is the optimal addition to improve the performance of steel slag carbonized products.

[0096] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the performance and carbon fixation rate of steel slag carbonized products, characterized in that: The specific steps include: (1) Calculate the following raw materials by mass percentage: 80-100 parts of steel slag powder, 13-17 parts of deionized water, and 1 part of alcoholamine; (2) weighing deionized water and ethanolamine to form an ethanolamine solution, placing it in a magnetic stirrer for stirring, and then continuously introducing 99.9% CO2 gas to carbonate the ethanolamine solution, and the ventilation time is controlled at 2 hours; (3) Add the carbonation-treated alcohol amine solution to the weighed steel slag powder and mix it with a slurry mixer until it is uniform; (4) pressing the steel slag mixture into steel slag product blocks by pressing and forming; (5) The steel slag product blocks are placed in a carbonization kettle, and CO2 gas with a purity of 99.9% is introduced to make steel slag carbonized products.

2. The method for preparing steel slag carbonized products with improved performance and carbon fixation rate according to claim 1, characterized in that: The raw materials weighed in step (1) also include 10-20 parts of lithium slag powder; in step (3), the alcohol amine solution after carbonation treatment is added to the weighed steel slag powder and lithium slag powder.

3. The method for preparing a steel slag carbonized product with improved performance and carbon fixation rate according to claim 1 or 2, characterized in that: The steel slag powder in step (1) is any one of converter steel slag, open-hearth steel slag and electric furnace steel slag.

4. The method for preparing a steel slag carbonized product with improved performance and carbon fixation rate according to claim 1 or 2, characterized in that: The alcohol amine in step (1) is any one of monoethanolamine, diethanolamine and triethanolamine.

5. The method for preparing a steel slag carbonized product with improved performance and carbon fixation rate according to claim 1 or 2, characterized in that: In step (2), the stirring temperature of the magnetic stirrer is 40-60° C., and the stirring rate is 100 r / min.

6. The method for preparing a steel slag carbonized product with improved performance and carbon fixation rate according to claim 1 or 2, characterized in that: The pressure of the pressing process in step (4) is 6-10 MPa, and the pressure is maintained for 30 seconds.

7. The method for preparing a steel slag carbonized product with improved performance and carbon fixation rate according to claim 1 or 2, characterized in that: In step (5), the pressure in the carbonization kettle is 0.1-0.3 MPa, and the carbonization time is 2 h.

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