Method for sequestration of carbon by using ferronickel slag and application
By alkali treatment and wet carbonization of nickel-iron slag powder, calcium carbonate crystals are generated, which solves the problems of high energy consumption and high pollution in the traditional cement production process, and achieves the promotion of efficient CO2 capture, storage and hydration processes.
Patent Information
- Application Number
- CN202510373196.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-27
- Publication Date
- 2025-05-27
AI Technical Summary
The production process of traditional silicate cement is high in energy consumption and high pollution, and its carbon sequestration capacity is limited, making it difficult to effectively capture and store CO2.
By immersing the nickel-iron slag powder in an alkali solution for pretreatment, it destroys its silicate structure and chemical bonds, and then undergoes wet carbonization to generate a large amount of calcium carbonate crystals, thereby improving the carbon sequestration ability of the nickel-iron slag.
It significantly improves the carbon sequestration capacity of nickel-iron slag, achieves efficient CO2 capture and storage, and promotes the hydration process of cement slurry, which has significant energy saving and emission reduction significance.
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Abstract
Description
Technical Field
[0001] The present invention relates to a method for carbon sequestration and its application, and particularly to a method for carbon sequestration using nickel-iron slag and its application. Background Art
[0002] Traditional portland cement is the most widely used cementitious material at present, but its production process is characterized by high energy consumption and high pollution. It not only consumes a large amount of fossil resources but also emits a large amount of CO 2 . However, CO 2 is also an abundant carbon source on the earth. Therefore, on the premise of considering CO 2 emission reduction, it can also be solidified and recycled into resources. CO 2 mineralization and sequestration is considered to be one of the most promising technologies.
[0003] Industrial solid wastes have many carbonization active components, are easy to carry out carbonization reactions, and have a large storage capacity of solid wastes. They are ideal raw materials for CO 2 mineralization and sequestration, and have the advantages of easy access, low cost, and reduction of environmental pollution. Moreover, after the industrial solid waste is mineralized and sequestered, problems such as its stability and activity can be solved, and the resource utilization rate can be improved.
[0004] The structure of nickel-iron slag is loose and porous, and its relatively high calcium oxide and magnesium oxide contents are the characteristics required for mineral carbonization, indicating that nickel-iron slag may have a relatively high CO 2 mineralization ability and can be used for carbon capture and sequestration. Common carbonization methods include: wet carbonization and dry carbonization (gas-solid carbonization). Wet carbonization is more widely used because it is more efficient than dry carbonization. The carbonization rate of wet carbonization depends to a large extent on the dissolution rate of alkali metal ions, and the dissolution rate is usually affected by factors such as the specific surface area, particle size, temperature, and solution pH of the sample. By adjusting the above parameters, the dissolution rate of alkali metal ions can be increased, but surface passivation of silicates is a common problem in wet carbonization. Due to the bond energy difference between M-O and Si-O, a silicon-rich layer will be formed on the sample at a relatively low pH during the carbonization process, thus preventing surface dissolution. In addition, carbonization products such as silica gel and carbonate will also precipitate on the surface of silicates, thus hindering dissolution. Summary of the Invention
[0005] Object of the Invention: The object of the present invention is to provide a method for carbon sequestration using nickel-iron slag that can significantly improve the carbon sequestration effect;
[0006] The second object of the present invention is to provide the application of the carbon-sequestered nickel-iron slag powder obtained by the above method in cement-based slurries.
[0007] Technical Solution: The method for carbon sequestration using nickel-iron slag according to the present invention includes the following steps:
[0008] (1) Immerse the nickel - iron slag powder in an alkali solution, and then obtain the alkali - treated nickel - iron slag powder through washing and drying;
[0009] (2) Mix and dissolve the alkali - treated nickel - iron slag powder with saturated carbonated water to obtain a nickel - iron slag powder suspension; Inject CO 2 gas into the nickel - iron slag powder suspension for wet carbonization;
[0010] (3) Centrifuge the solution after wet carbonization to obtain a solid product, and then obtain the carbon - fixed nickel - iron slag powder co - treated by alkali - wet carbonization through drying.
[0011] Among them, in step (1), the concentration of the nickel - iron slag powder in the alkali solution is 2 - 6 mol / L.
[0012] Among them, in step (1), the liquid - solid ratio of the nickel - iron slag powder to the alkali solution is 5:1 - 10:1.
[0013] Among them, in step (1), preferably, the temperature of the alkali treatment process is 60 °C and the time is 2 h.
[0014] Among them, in step (1), the alkali treatment process is carried out under mechanical stirring conditions, and the rotation speed of the mechanical stirring is 300 rpm - 600 rpm.
[0015] Among them, in step (1), the particle size of the used nickel - iron slag powder is less than or equal to 75 μm.
[0016] Among them, in step (2), the liquid - solid ratio of the nickel - iron slag powder to the saturated carbonated water is 10:1 - 50:1.
[0017] Among them, in step (2), when injecting CO 2 gas into the nickel - iron slag powder suspension, keep the temperature of the nickel - iron slag powder suspension at 10 °C - 60 °C.
[0018] Among them, in step (2), when injecting CO 2 gas into the nickel - iron slag powder suspension, the flow rate of the gas is 50 - 200 mL / min, and the duration is 3 - 48 h.
[0019] Among them, in step (2), when injecting CO 2 gas into the nickel - iron slag powder suspension, carry out mechanical stirring at a rate of 300 - 600 rpm / min.
[0020] Application of the carbon - fixed nickel - iron slag powder obtained by the above method in a cement - based slurry.
[0021] Among them, the cement - based material includes the following components by mass:
[0022] Cement 70 parts;
[0023] 0 - 30 parts of carbon - fixed nickel - iron slag powder obtained by the method of claim 1;
[0024] 45 parts of water.
[0025] Beneficial effects: Compared with the prior art, the present invention has the following remarkable effects:
[0026] (1) In the present invention, the nickel - iron slag powder is pretreated with an alkali solution and then wet - carbonized. The alkali treatment process can highly destruct the silicate structure and chemical bonds such as Ca - O and Si - O in the nickel - iron slag powder. The wet - carbonization process can generate calcium carbonate crystals mainly in the form of a large amount of calcite in the nickel - iron slag powder, which can highly improve the carbon - fixation ability of the nickel - iron slag. Moreover, the carbon - fixed nickel - iron slag used as a mineral admixture can promote the hydration process of the cement paste.
[0027] (2) Compared with other carbon - fixation methods, the method of the present invention adds a pretreatment method of soaking with an alkali solution, which can effectively destruct the surface passivation layer of the nickel - iron slag and achieve high - efficiency carbon - fixation of the nickel - iron slag.
[0028] (3) Compared with cement, the carbon - fixed nickel - iron slag incorporated as a mineral admixture can promote the hydration process of the paste. The nickel - iron slag treated by this method can not only improve the resource utilization rate of solid waste but also absorb carbon dioxide, which has significant significance for energy conservation and emission reduction. Description of the Drawings
[0029] Figure 1 XRD analysis pattern of the nickel - iron slag powder in Example 5;
[0030] Figure 2 Thermogravimetric analysis of the alkali - wet - carbonized nickel - iron slag powder in Example 5;
[0031] Figure 3 Microscopic structures of the alkali - treated nickel - iron slag powder, alkali - wet - carbonized nickel - iron slag powder and untreated nickel - iron slag powder in Example 5 observed under an electron scanning electron microscope;
[0032] Figure 4 Test results of the hydration heat of the paste of the carbon - fixed nickel - iron slag powder. Detailed Description of the Invention
[0033] The present invention will be further described in detail below.
[0034] The nickel - iron slag used in the present invention comes from Fuzhou, Fujian, China. The chemical composition of the nickel - iron slag is shown in Table 1.
[0035] Table 1 Chemical composition of nickel - iron slag powder, wt.%
[0036]
[0037] Example 1
[0038] The nickel-iron slag powder was ground to a particle size below 75 μm. An appropriate amount of the powder was added to a sodium hydroxide solution, and the concentration of the nickel-iron slag powder in the sodium hydroxide solution was controlled at 2 mol / L. The mass ratio of the sodium hydroxide solution to the nickel-iron slag powder (hereinafter referred to as the liquid-solid ratio) was controlled at 5:1. Under the control of a constant temperature water bath at 60 °C, a mechanical stirrer with digital display was used to stir at a speed of 300 rpm for 2 h. The filtered solid was washed twice with deionized water and anhydrous ethanol respectively, and then dried in a vacuum drying oven at 40 °C for 72 h to obtain the alkali-treated nickel-iron slag powder.
[0039] Subsequently, wet carbonization technology was used for further treatment: The dried nickel-iron slag powder was placed in a beaker, and deionized water was added to the beaker. The mass ratio of the deionized water to the nickel-iron slag powder (hereinafter referred to as the liquid-solid ratio) was controlled at 10:1. Under the environment of a constant temperature water bath at 10 °C, 99.9% CO 2 gas was injected into the solution at a flow rate of 50 mL / min for 3 h, and at the same time, the mechanical stirrer was controlled to stir at a speed of 300 rpm. After stirring, the solid was separated by centrifugation and dried in a vacuum drying oven at 40 °C for 72 h to obtain the carbon-fixing nickel-iron slag powder co-treated with alkali and wet carbonization.
[0040] The calcium carbonate content in the nickel-iron slag powder was tested by thermogravimetric analysis to calculate the carbon-fixing ability of the nickel-iron slag powder. The degree of carbonization of the sample was calculated based on the weight loss at different decomposition temperatures. During the test, about 10 mg of the powder was placed in an alumina crucible and heated from 30 °C to 1000 °C at a heating rate of 10 °C / min for testing in a nitrogen environment. Calcium carbonate usually decomposes into CaO and CO 2 , but the starting temperature and ending temperature of the weight loss of calcium carbonate will vary due to different samples, and the tangent method can be used to determine its temperature. The weight loss can be used to calculate the amount of calcium carbonate present, using the molecular mass 3 of CaCO and the molecular mass 2 of CO for calculation (Equation 1):
[0041]
[0042] The content of CaCO 3 in the nickel-iron slag was calculated according to formula (1), and the results are shown in Table 2.
[0043] Example 2
[0044] The nickel - iron slag powder was ground to a particle size below 75 μm. An appropriate amount of the powder was added to a sodium hydroxide solution, with the solution concentration controlled at 4 mol / L and the liquid - solid ratio controlled at 5:1. Under the control of a 60°C constant - temperature water bath, a mechanical stirrer with digital display was used to stir at a speed of 300 rpm for 2 h. The filtered solid was washed twice with deionized water and anhydrous ethanol respectively, and then dried in a vacuum drying oven at 40°C for 72 h. The alkali - treated nickel - iron slag powder was obtained.
[0045] Subsequently, it was further treated using the wet carbonization technique: The dried sample was placed in a beaker, and deionized water was added to the beaker. The liquid - solid ratio was controlled at 10:1 during this process. Under a 10°C constant - temperature water - bath environment, 99.9% CO 2 gas was injected into the solution at a flow rate of 50 mL / min for 3 h, while stirring was carried out with a mechanical stirrer at a speed of 300 rpm. The solid was separated by centrifugation and dried in a vacuum drying oven at 40°C for 72 h to obtain the nickel - iron slag powder co - treated with alkali and wet carbonization.
[0046] Calculate the CaCO 3 content in the nickel - iron slag according to formula (1), and the results are shown in Table 2.
[0047] Example 3
[0048] The nickel - iron slag powder was ground to a particle size below 75 μm. An appropriate amount of the powder was added to a sodium hydroxide solution, with the solution concentration controlled at 6 mol / L and the liquid - solid ratio controlled at 5:1 respectively. Under the control of a 60°C constant - temperature water bath, a mechanical stirrer with digital display was used to stir at a speed of 300 rpm for 2 h. The filtered solid was washed twice with deionized water and anhydrous ethanol respectively, and then dried in a vacuum drying oven at 40°C for 72 h. The alkali - treated nickel - iron slag powder was obtained.
[0049] Subsequently, it was further treated using the wet carbonization technique: The dried sample was placed in a beaker, and deionized water was added to the beaker. The liquid - solid ratio was controlled at 10:1 during this process. Under a 10°C constant - temperature water - bath environment, 99.9% CO 2 gas was injected into the solution at a flow rate of 50 mL / min for 3 h, while stirring was carried out with a mechanical stirrer at a speed of 300 rpm. The solid was separated by centrifugation and dried in a vacuum drying oven at 40°C for 72 h to obtain the nickel - iron slag powder co - treated with alkali and wet carbonization.
[0050] Calculate the CaCO 3 content in the nickel - iron slag according to formula (1), and the results are shown in Table 2.
[0051] Result analysis of Example 1, Example 2, and Example 3:
[0052] Example 3. Compared with Example 1, the preparation methods of Example 2 and Example 3 are basically exactly the same. The difference lies in that the concentration of the sodium hydroxide solution is higher in the alkali treatment process. In Example 1, the calcium carbonate content of the nickel-iron slag powder was 8.215% as measured by thermogravimetry, while the calcium carbonate content of the nickel-iron slag powder in Example 2 was 13.653%, and that in Example 3 was 18.899%. The comparison of the three can confirm that the concentration of the sodium hydroxide solution in the alkali treatment process has a significant impact on the subsequent carbonization effect. The higher the concentration, the higher the calcium carbonate content in the nickel-iron slag powder, and the better the carbon sequestration effect.
[0053] Example 4
[0054] The nickel-iron slag powder was ground to a particle size of less than 75 μm. An appropriate amount of the powder was added to the sodium hydroxide solution, the solution concentration was controlled at 4 mol / L, the liquid-solid ratio was controlled at 10:1, and under the control of a constant temperature water bath at 60 °C, it was stirred with a mechanical stirrer with digital display at a rotation speed of 300 rpm for 2 h. The filtered solid was washed twice with deionized water and anhydrous ethanol respectively, and then dried in a vacuum drying oven at 40 °C for 72 h. The alkali-treated nickel-iron slag powder was obtained.
[0055] Subsequently, it was further treated by the wet carbonization technique: The dried sample was placed in a beaker, and deionized water was added to the beaker. The liquid-solid ratio was controlled at 10:1 in this process. Under the environment of a constant temperature water bath at 10 °C, 99.9% CO 2 gas was injected into the solution at a flow rate of 50 mL / min for 3 h, and at the same time, the mechanical stirrer was rotated at a speed of 300 rpm for stirring. The solid was separated by centrifugation and dried in a vacuum drying oven at 40 °C for 72 h to obtain the nickel-iron slag powder co-treated with alkali and wet carbonization. The CaCO 3 content in the nickel-iron slag was calculated according to formula (1), and the results are shown in Table 2.
[0056] Compared with Example 2, in this example, the liquid-solid ratio in the alkali treatment process was increased, and the calcium carbonate content of the nickel-iron slag powder was further increased, reaching 20.366%. The carbon sequestration effect exceeded that of Example 3, indicating that the liquid-solid ratio in the alkali treatment process can also highly affect the carbon sequestration ability of the nickel-iron slag powder.
[0057] Example 5
[0058] The nickel-iron slag powder was ground to a particle size of less than 75 μm. An appropriate amount of the powder was added to the sodium hydroxide solution, the solution concentration was controlled at 4 mol / L, the liquid-solid ratio was controlled at 10:1, and under the control of a constant temperature water bath at 60 °C, it was stirred with a mechanical stirrer with digital display at a rotation speed of 600 rpm for 2 h. The filtered solid was washed twice with deionized water and anhydrous ethanol respectively, and then dried in a vacuum drying oven at 40 °C for 72 h. The alkali-treated nickel-iron slag powder was obtained.
[0059] Subsequently, wet carbonization technology was further used for treatment: the dried sample was placed in a beaker, and deionized water was added to the beaker. The liquid-solid ratio was controlled at 10:1 during this process. Under the environment of a constant temperature water bath at 10 °C, 99.9% CO 2 gas was injected into the solution at a flow rate of 50 mL / min for 3 h, and at the same time, the stirrer speed of the pore mechanical stirrer was 300 rpm for stirring. The solid was separated by centrifugation and dried in a vacuum drying oven at 40 °C for 72 h to obtain nickel-iron slag powder co-treated with alkali and wet carbonization. The content of CaCO 3 in the nickel-iron slag was calculated according to formula (1), and the results are shown in Table 2.
[0060] Compared with Example 4, the stirring rate in the alkali treatment process was increased in this example. Compared with Example 2, the liquid-solid ratio and the stirring rate in the alkali treatment process were increased simultaneously in this example. The calcium carbonate content can reach 22.743%. Compared with the untreated nickel-iron slag, the calcium element mineralization rate can reach 77.28%, and the carbon sequestration ability has achieved a relatively high degree of growth.
[0061] Figure 1 is the XRD analysis pattern of the nickel-iron slag powder of Example 5. After analysis, its main carbonization product is calcite.
[0062] Figure 2 is the thermogravimetric analysis of the alkali-wet carbonization treated nickel-iron slag powder of Example 5. It can be clearly seen from the analysis results that a large amount of calcium carbonate decomposition occurred in the nickel-iron slag powder after alkali-wet carbonization treatment.
[0063] Figure 3 are the microstructures of the alkali-treated nickel-iron slag powder, the alkali-wet carbonization treated nickel-iron slag powder, and the untreated nickel-iron slag powder of Example 5 observed under an electron scanning electron microscope. It can be clearly seen that the surface and internal structures of the nickel-iron slag powder are eroded and damaged after alkali treatment; a large number of spherical and rhombic structure crystals are generated on the surface of the nickel-iron slag powder after alkali-wet carbonization treatment, corresponding to the vaterite and calcite crystal forms of calcium carbonate crystals respectively.
[0064] According to the subsequent test results, considering the carbonization rate of the nickel-iron slag powder and the output problem during the alkali-wet carbonization treatment process, the hydration heat release characteristics of ACFNS were tested using the carbon sequestration nickel-iron slag powder of Example 5. Among them, the calcium carbonate content of the carbon sequestration nickel-iron slag of Example 5 was quantitatively calculated by TG-DTG to be 22.74%. The ratio of using nickel-iron slag powder to replace 30% of the cement quality was adopted, the water-binder ratio of the paste was controlled at 0.45, and the ratio of the carbon sequestration nickel-iron slag powder to the ordinary nickel-iron slag powder was changed to control the content of the carbon sequestration nickel-iron slag powder in the system to be 30%, 20%, 15%, and 0% respectively, obtaining groups CC, CFC2, CFC1, and CF. The hydration heat of the paste was tested to comprehensively evaluate the influence of the alkali-wet carbonization nickel-iron slag powder on the hydration heat release characteristics of the composite cementitious material system. As Figure 4As shown in the figure, it is found through the hydration heat results that the carbonated nickel-iron slag powder has an obvious promoting effect on the hydration heat results; the higher the content of carbonated nickel-iron slag powder in the system, the more obvious the hydration promoting effect of the paste.
[0065] Comparative Example 1
[0066] The nickel-iron slag powder was ground to a particle size of less than 75 μm and directly treated by the wet carbonization technique. An appropriate amount of dry nickel-iron slag powder was placed in a beaker, and deionized water was added to control the liquid-solid ratio to 50:1. In a constant temperature water bath environment at 60 °C, 99.9% CO 2 gas was injected into the solution at a flow rate of 50 mL / min for 3 h, and at the same time, the rotational speed of the hole mechanical stirrer was 300 rpm for stirring. The solid was separated by centrifugation and dried in a vacuum drying oven at 40 °C for 72 h to obtain nickel-iron slag powder. The content of CaCO 3 in the nickel-iron slag was calculated according to formula (1), and the results are shown in Table 2.
[0067] Comparative Example 2
[0068] The nickel-iron slag powder was ground to a particle size of less than 75 μm and directly treated by the wet carbonization technique. An appropriate amount of dry nickel-iron slag powder was placed in a beaker, and deionized water was added to control the liquid-solid ratio to 25:1. In a constant temperature water bath environment at 10 °C, 99.9% CO 2 gas was injected into the solution at a flow rate of 50 mL / min for 3 h, and at the same time, the rotational speed of the hole mechanical stirrer was 300 rpm for stirring. The solid was separated by centrifugation and dried in a vacuum drying oven at 40 °C for 72 h to obtain nickel-iron slag powder. The content of CaCO 3 in the nickel-iron slag was calculated according to formula (1), and the results are shown in Table 2.
[0069] Comparative Example 3
[0070] The nickel-iron slag powder was ground to a particle size of less than 75 μm and directly treated by the wet carbonization technique. An appropriate amount of dry nickel-iron slag powder was placed in a beaker, and deionized water was added to control the liquid-solid ratio to 10:1. In a constant temperature water bath environment at 10 °C, 99.9% CO 2 gas was injected into the solution at a flow rate of 200 mL / min for 48 h, and at the same time, the rotational speed of the hole mechanical stirrer was 300 rpm for stirring. The solid was separated by centrifugation and dried in a vacuum drying oven at 40 °C for 72 h to obtain nickel-iron slag powder. The content of CaCO 3 in the nickel-iron slag was calculated according to formula (1), and the results are shown in Table 2.
[0071] Comparative Example 1 was adjusted to high-temperature carbonization; Comparative Example 2 was adjusted to low-temperature carbonization; Comparative Example 3 extended the carbonization time and increased the carbon dioxide gas flow rate. None of the above comparative examples significantly improved the carbonization rate, indicating that alkali treatment can effectively enhance the carbon sequestration ability of nickel-iron slag.
[0072] Calcium carbonate content of nickel-iron slag powder in each example and comparative example in Table 2
[0073]
[0074] From the calculation results of the calcium carbonate content of the above Examples 1-5 and Comparative Examples 1-3, it can be seen that the present invention can efficiently fix carbon in nickel-iron slag. Adding a pretreatment step of alkali treatment can better destroy and reorganize the structure of nickel-iron slag powder, which is beneficial to the formation of more calcium carbonate in the subsequent wet carbonization treatment and improves the carbon fixation ability of nickel-iron slag.
Claims
1. A method for carbon fixation using nickel-iron slag, characterized in that: The following steps are involved: (1) ferronickel slag powder is immersed in an alkaline solution, and then washed and dried to obtain the ferronickel slag powder after the alkali treatment; (2) mixing and dissolving the ferronickel slag powder after the alkali treatment with saturated carbonated water to obtain a ferronickel slag powder suspension; injecting CO2 gas into the ferronickel slag powder suspension for wet carbonization; (3) The wet carbonized suspension is centrifuged to obtain a solid product, which is then dried to obtain a carbon-fixed nickel-iron slag powder treated by alkali-wet carbonization.
2. The method for carbon fixation using ferronickel slag according to claim 1, characterized in that: In step (1), in step (1), the concentration of the nickel-iron slag powder in the alkaline solution is 2 mol / L-6 mol / L.
3. The method for carbon fixation using ferronickel slag according to claim 1, characterized in that: In step (1), in step (1), the liquid-to-solid ratio of the nickel-iron slag powder and the alkaline solution is 5:1-10:
1.
4. The method for carbon fixation using ferronickel slag according to claim 1, characterized in that: In step (1), the alkali treatment process is carried out under mechanical stirring conditions, and the rotation speed of the mechanical stirring is 300rpm-600rpm.
5. The method for carbon fixation using ferronickel slag according to claim 1, characterized in that: In step (1), the particle size of the nickel-ferronickel slag powder is less than or equal to 75 μm.
6. The method for carbon fixation using ferronickel slag according to claim 1, characterized in that: In step (2), the liquid-to-solid ratio of the nickel-ferro slag powder to saturated carbonated water is 10:1-50:
1.
7. The method for carbon fixation using ferronickel slag according to claim 1, characterized in that: In step (2), when CO2 gas is injected into the ferronickel slag powder suspension, the temperature of the ferronickel slag powder suspension is maintained at 10°C-60°C.
8. Use of the carbon-fixing ferronickel slag powder obtained by the method according to claim 1 in cement-based slurry.
9. The use of the carbon-fixing ferronickel slag powder in cement-based slurry according to claim 8, characterized in that: The cement-based material comprises the following components in parts by mass: 70 parts of cement; 0-30 parts of carbon-fixed ferronickel slag powder obtained by the method of claim 1; 45 parts of water.