Preparation method and application of kiln slag-based Fe2O3 / C catalytic material
By preparing kiln slag-based Fe2O3/C catalytic materials, the problems of high cost and poor stability of SF6 degradation catalysts have been solved, achieving efficient and economical sulfur hexafluoride degradation, suitable for industrial application, and possessing good environmental and economic benefits.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 河套学院
- Filing Date
- 2026-03-17
- Publication Date
- 2026-05-05
AI Technical Summary
Existing SF6 degradation catalysts are costly, complex to prepare, have poor stability, require harsh reaction conditions, and have low utilization rates of industrial kiln slag, making it difficult to achieve large-scale application.
Using zinc smelting rotary kiln slag as raw material, a slag-based Fe2O3/C catalytic material was prepared through pretreatment, calcination, and ball milling. Combined with Ag loading, it achieved efficient catalytic degradation of sulfur hexafluoride and is suitable for operation under normal pressure air atmosphere.
With a degradation rate as high as 63.99%, it has good resistance to sulfur and fluoride poisoning, a long service life, easy-to-treat degradation products, meets environmental protection requirements, is suitable for industrial production, and reduces engineering application costs.
Smart Images
Figure CN121972165A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of materials technology, specifically to a method for preparing Fe2O3 / C composite catalytic materials using zinc smelting rotary kiln slag as raw material, and its application in the catalytic degradation of the potent greenhouse gas sulfur hexafluoride (SF6) in air atmosphere. Background Technology
[0002] Global climate change has become a severe challenge facing humanity, and reducing emissions of potent greenhouse gases is key to addressing this challenge. Sulfur hexafluoride (SF6), due to its excellent electrical insulation and arc-quenching properties, is widely used in ultra-high voltage (UHV) power transmission and transformation equipment and electrical switches, making it an indispensable key medium in the power industry. However, SF6's global warming potential (GWP) is as high as 24,300 times that of CO2, and it can remain stable in the atmosphere for hundreds to thousands of years, making it one of the most potent greenhouse gases known. The geographical disparities in my country's energy distribution necessitate UHV ultra-long-distance power transmission, leading to a continuous increase in SF6 usage in my country's power system. According to surveys, my country's in-service SF6 usage exceeded 100,000 tons in 2020, and is growing at a rate of over 20% annually. Its large-scale emissions have become a significant obstacle to my country's achievement of its "dual carbon" (carbon dioxide, carbon dioxide, and sulfur dioxide) goals. Therefore, developing efficient, economical, and scalable SF6 degradation technologies has become a critical issue urgently needing to be addressed by the environmental protection and power industries.
[0003] Currently, there are various methods for degrading sulfur hexafluoride, including adsorption, traditional industrial thermal decomposition, photodegradation, plasma method, and catalytic degradation. Among them, catalytic degradation can convert sulfur hexafluoride into harmless or easily treatable substances under relatively mild conditions, which is a promising end-of-pipe treatment technology. The core of this technology lies in designing a bifunctional catalyst that can simultaneously achieve the adsorption of sulfur hexafluoride molecules and the activation of strong SF bonds. In existing catalytic degradation technologies, catalysts mostly rely on noble metals (such as Pt, Pd, Au, and Ag) or special heterostructures (such as FeOOH / SiC, Ga / Al2O3). However, there are significant drawbacks: (1) Noble metal raw materials are scarce and expensive, and the preparation process of special heterostructures is complex, resulting in high costs for large-scale production of catalysts; (2) Catalysts are easily poisoned by fluorine and sulfur species during the reaction process, and are often deactivated due to irreversible oxidation of active metal sites, resulting in poor cycle stability; Thirdly, most catalysts need to operate in an inert atmosphere above 600℃ or under specific harsh conditions, which is out of touch with the actual atmospheric environment and seriously limits their practical application value.
[0004] Zinc smelting rotary kiln slag, a typical bulk industrial solid waste, mainly consists of iron, zinc, carbon, and silicon, possessing potential activity as a catalytic material. However, there are currently no reports on technologies for directly using kiln slag for SF6 degradation, and the high-value utilization potential of industrial solid waste has not been fully explored. Therefore, addressing the dual technical pain points of existing SF6 degradation catalysts—high cost, complex preparation, poor stability, and harsh reaction conditions—and the low resource utilization rate of industrial kiln slag, this paper aims to develop an SF6 degradation catalytic material based on industrial solid waste kiln slag, with a simple process, low cost, excellent performance, and suitability for practical application scenarios. This material would possess both environmental and economic benefits, and has significant academic value and industrial application prospects. Summary of the Invention
[0005] The first objective of this invention is to provide a method for preparing a slag-based Fe2O3 / C catalytic material using industrial solid waste zinc smelting rotary kiln slag as raw material, without the need to add additional active components or carbon sources, and with a simple process and low cost.
[0006] The technical solution adopted in this invention is as follows: A method for preparing a kiln slag-based Fe2O3 / C catalytic material includes the following steps: (1) Pretreatment: The zinc smelting rotary kiln slag is pretreated to obtain kiln slag raw material with uniform particle size; (2) Calcination: The kiln slag pretreated in step (1) is calcined at 900℃~1500℃ for 1-4 hours in air or a weak oxidizing atmosphere, and then cooled. (3) Ball milling: The cooled kiln slag in step (2) is ball milled to obtain powdered kiln slag-based Fe2O3 / C catalyst.
[0007] Further settings include: In step (1): The kiln slag contains the following composition by mass fraction: Fe ≥ 30%, Ca ≤ 10%, Si ≤ 5%, Zn ≤ 5%, C ≥ 15%, and total impurities ≤ 10%.
[0008] The pretreatment includes crushing and screening. The crushing involves crushing the kiln slag to a particle size ≤10mm, and the screening involves passing the crushed material through a 10-50 mesh sieve to obtain kiln slag raw material with uniform particle size.
[0009] In step (2): The calcination is preferably carried out in an air atmosphere.
[0010] The preferred calcination temperature is 1500℃, the time is 2 hours, and the heating rate is 15℃·min. -1 .
[0011] In step (3): The ball milling is carried out in a ball mill, using agate balls as the grinding media, with a ball-to-material ratio of 5-15:1, a rotation speed of 100-300 rpm, and a time of 15-60 minutes. Particularly preferred is a ball-to-material ratio of 10:1, a rotation speed of 200 rpm, and a time of 30 minutes.
[0012] The present invention also provides a method for preparing Ag-supported kiln slag-based Fe2O3 / C catalytic material, comprising the following steps: mixing the aforementioned prepared powdered kiln slag-based Fe2O3 / C catalytic material with metallic Ag powder in a certain proportion, and then performing ball milling to obtain Ag-supported kiln slag-based Fe2O3 / C catalytic material.
[0013] The Ag loading amount, based on the total mass of the mixed materials, is 1 wt% to 10 wt%, preferably 5 wt%.
[0014] The ball milling is carried out in a ball mill with a ball-to-material ratio of 10:1 at 300 rpm for 1 hour. This ensures that the Ag particles are uniformly and firmly dispersed and loaded on the carrier surface, and enhances the interfacial contact between Ag and the Fe2O3 / C carrier.
[0015] The second objective of this invention is to provide the application of the aforementioned kiln slag-based Fe2O3 / C catalytic material in the catalytic degradation of sulfur hexafluoride, using the kiln slag-based Fe2O3 / C catalytic material as a catalyst to catalytically degrade sulfur hexafluoride under normal pressure and air atmosphere.
[0016] Furthermore, the application of a kiln slag-based Fe2O3 / C catalytic material in the catalytic degradation of sulfur hexafluoride includes the following steps: (1) A sulfur hexafluoride mixed gas is introduced into a reactor containing kiln slag-based Fe2O3 / C catalyst material. The mixed gas consists of sulfur hexafluoride and air, wherein the volume concentration of sulfur hexafluoride is 5% to 20%. (2) Heat the reactor to 400℃~600℃ to carry out the catalytic degradation reaction; (3) The exhaust gas after step (2) is treated with an alkaline solution.
[0017] Preferably: In step (1), the volume concentration of sulfur hexafluoride in the mixed gas is 10 vol.%. The flow rate of the mixed gas is 10 mL·min. -1 This ensures that sulfur hexafluoride molecules are in full contact with the active sites of the catalyst.
[0018] In step (2), at 15℃·min -1The temperature is increased to 400℃~600℃ at a controlled heating rate, and the reaction is carried out for 1~3 hours. The preferred degradation temperature is 600℃, and the reaction is carried out for 2 hours. This temperature maximizes catalytic activity and achieves efficient degradation of sulfur hexafluoride.
[0019] In step (3), the alkaline solution is 5 mol·L⁻¹. -1 Sodium hydroxide solution. It can efficiently absorb acidic gases such as HF and SO2 in the degradation products, avoiding secondary pollution.
[0020] Compared with the prior art, the present invention has the following advantages: This invention uses industrial solid waste kiln slag from zinc smelting directly as raw material, without the need to add precious metals or additional active components. This not only significantly reduces the preparation cost of catalytic materials, but also solves the environmental problem of industrial solid waste stockpiling, realizing the high-value utilization of industrial solid waste, which is in line with the concept of circular economy and the "dual carbon" target requirements.
[0021] High-performance catalysts can be prepared through a simple ball milling and calcination process. The process route is short and easy to operate, requiring no complex equipment or harsh reaction conditions, making it suitable for large-scale industrial production.
[0022] By optimizing the calcination temperature, iron oxides and residual carbon inside the kiln slag undergo an in-situ reaction, forming a Fe2O3 / C nanocomposite structure. This material achieves a degradation rate of 63.99% for 10% sulfur hexafluoride at 600℃, significantly outperforming the Ag-Fe2O3 / C system supported by precious metal silver. It also exhibits excellent resistance to sulfur and fluoride poisoning, maintaining a degradation rate above 58.9% even after 12 hours of continuous reaction, demonstrating a long service life.
[0023] It can efficiently degrade SF6 in air atmosphere and normal pressure without the need for inert protective atmospheres such as nitrogen and argon. The reaction conditions are exactly the same as the actual atmospheric environment, which reduces the cost of engineering applications and has broad prospects for practical applications.
[0024] The degradation products are mainly acidic gases such as HF and SO2, which can be efficiently absorbed by NaOH solution. There are no toxic or harmful gas emissions, which meets environmental protection requirements and avoids secondary pollution.
[0025] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description
[0026] Figure 1 This is a process flow diagram for the preparation of kiln slag-based Fe2O3 / C catalytic materials.
[0027] Figure 2 XRF images of different batches of kiln slag.
[0028] Figure 3XRD patterns of different batches of kiln slag.
[0029] Figure 4 The image shows the XRD pattern of the kiln slag used in Example 1.
[0030] Figure 5 The image shows the XRD pattern of the kiln slag-based Fe2O3 / C catalytic material prepared in Example 1.
[0031] Figure 6 Scanning electron microscope images of the kiln slag-based Fe2O3 / C catalytic material prepared in Example 1 at different magnifications.
[0032] Figure 6 middle: Figure 6 a represents the overall morphology of the catalytic material at 1000x magnification, with a scale bar of 200 μm; Figure 6 b represents the overall morphology of other regions at the same magnification, with a scale bar of 200 μm; Figure 6 c represents the local magnified morphology at 5000x magnification, with a scale bar of 40μm; Figure 6 d represents the high-magnification fine morphology at 20,000x magnification, with a scale bar of 10 μm.
[0033] Figure 7 The image shows the HRTEM lattice image of the kiln slag-based Fe2O3 / C catalytic material prepared in Example 1.
[0034] Figure 8 Performance curves of SF6 degradation by Fe2O3 / C prepared in Example 1 and 5 w% Ag-Fe2O3 / C prepared in Example 5.
[0035] Figure 9 Arrhenius curves showing the degradation of SF6 by Fe2O3 / C prepared in Example 1 and 5 w% Ag-Fe2O3 / C prepared in Example 5.
[0036] Figure 10 This is a schematic diagram of a device for catalytic degradation of SF6 using kiln slag-based Fe2O3 / C catalyst.
[0037] Figure 10 Labeling of each component: 1 - Mixed gas storage device; 2 - Mass flow meter; 3 - Tube furnace; 4 - Quartz reaction tube; 5 - NaOH alkaline solution absorption device; 6 - Gas chromatograph; A - Gas inlet; B - Processed gas outlet. Detailed Implementation
[0038] Unless otherwise specified, the experimental materials and equipment used in the following examples are commercially available.
[0039] In this example, the kiln slag raw materials selected were seven batches of kiln slag produced by the zinc smelting rotary kiln of Bayannur Zijin Nonferrous Metals Co., Ltd. The core components (mass fraction) of each batch of kiln slag met the following requirements: Fe ≥ 30%, Ca ≤ 10%, Si ≤ 5%, Zn ≤ 5%, C ≥ 15%, and total impurity content ≤ 10%. XRF testing of the above kiln slag was performed as follows: Figure 2 As shown: the fifth batch of kiln slag had a relatively low Fe content and a slightly higher Zn content, but still met the requirements of this invention. The XRD analysis of the above kiln slag is as follows: Figure 3 , Figure 4 As shown: The main phases of the kiln slag are a mixture of Fe3O4 (PDF#89-0950) and Zn2SiO4 (PDF#40-0007).
[0040] Example 1
[0041] like Figure 1 As shown, the preparation method of a kiln slag-based Fe2O3 / C catalytic material of the present invention has the following process flow: Raw material selection: In this embodiment, the raw material selected is the fourth batch of kiln slag produced by zinc smelting at Bayannur Zijin Nonferrous Metals Co., Ltd. The XRF analysis of this batch of kiln slag was conducted according to... Figure 2 As shown, its XRD detection reference Figure 4 As shown: The main phases of the kiln slag are a mixture of Fe3O4 (PDF#89-0950) and Zn2SiO4 (PDF#40-0007).
[0042] Pretreatment: The above-mentioned kiln slag is first crushed to a particle size of ≤10mm using a crusher, and then passed through a 50-mesh sieve to obtain kiln slag raw material with uniform particle size.
[0043] (3) Calcination: The pretreated kiln slag is placed in a muffle furnace and calcined at 15°C·min under an air atmosphere. -1 The temperature was raised to 1500℃ using the programmed heating rate, held for 2 hours, and then allowed to cool naturally to room temperature.
[0044] (4) Ball milling: The cooled calcined product is transferred to a ball mill, and agate balls are used as the grinding medium. The ball-to-material ratio is controlled at 10:1. The ball milling is carried out at 200 rpm for 30 min to obtain powdered kiln slag-based Fe2O3 / C catalytic material, which is labeled as Fe2O3 / C.
[0045] Product characterization: Figure 5The XRD pattern of the kiln slag-based Fe2O3 / C catalytic material prepared in Example 1 shows characteristic Fe2O3 diffraction peaks at 2θ = 24.1°, 33.2°, and 35.6° (PDF:#98-015-4191), and a broadened diffraction peak for amorphous carbon at 2θ = 26.6° (PDF:#98-061-7290), confirming the formation of the Fe2O3 / C composite structure.
[0046] Figure 6 The images shown are scanning electron microscope images of the kiln slag-based Fe2O3 / C catalytic material prepared in Example 1 at different magnifications. It can be seen that the material particles are evenly distributed, without obvious agglomeration, and the surface is rough, providing sufficient contact area for the reactant gas.
[0047] Figure 7 The image shows the HRTEM lattice image of the kiln slag-based Fe2O3 / C catalytic material prepared in Example 1. It clearly shows the tight bonding interface between the Fe2O3 lattice fringes and the graphite carbon, verifying the successful preparation of the composite structure.
[0048] Example 2
[0049] The preparation method is the same as in Example 1, except that the calcination temperature in step (2) is adjusted to 900℃, and the resulting catalyst material is labeled as Fe2O3 / C-9.
[0050] Example 3
[0051] The preparation method is the same as in Example 1, except that the calcination temperature in step (2) is adjusted to 1100℃, and the resulting catalyst material is labeled as Fe2O3 / C-11.
[0052] Example 4
[0053] The preparation method is the same as in Example 1, except that the calcination temperature in step (2) is adjusted to 1300℃, and the resulting catalyst material is labeled as Fe2O3 / C-13.
[0054] Application Example 1 The kiln slag-based Fe2O3 / C catalytic materials prepared in Examples 1-4 were applied to the degradation process of sulfur hexafluoride to test their catalytic performance.
[0055] The equipment used in the degradation process, such as Figure 10 As shown: The mixed gas storage device 1 (such as a gas storage tank) is used to store the mixed gas of SF6 and air. After the flow rate of the mixed gas is controlled by the mass flow meter 2, it enters the quartz reaction tube 4 containing kiln slag-based Fe2O3 / C catalyst material. The quartz reaction tube 4 is placed in the tube furnace 3. The tail gas after the reaction is passed into the NaOH alkaline solution absorption device 5 for treatment. The SF6 concentration at the outlet is analyzed by an online gas chromatograph 6 (TCD detector).
[0056] The degradation process steps are as follows: A mixture of air and SF6 (SF6 volume concentration of 10 vol.%) was prepared, and the flow rate of the mixture was controlled at 10 mL / min using mass flow meter 2. -1 .
[0057] Weigh 1 g of kiln slag-based Fe2O3 / C catalyst material and place it in quartz reaction tube 4. Seal the reaction system and purge the system with the above mixed gas for 30 min before the reaction begins to remove air from the system.
[0058] (3) Passing through tube furnace 3 at 15 °C·min -1 The temperature was increased to 600℃ at a certain rate, and the reaction was maintained at that temperature for 2 hours.
[0059] (4) The tail gas after the reaction is passed through a 5 mol·L⁻¹ solution. -1 In a sodium hydroxide solution, acidic gases such as HF and SO2 in the degradation products are absorbed, and the concentration of SF6 at the outlet is analyzed using an online gas chromatograph 6 (TCD detector) to calculate the degradation rate.
[0060] The formula for calculating the degradation rate is as follows: .
[0061] Where: C0 is the initial concentration of sulfur hexafluoride before degradation treatment, in mg·L⁻¹ -1 C t The concentration of sulfur hexafluoride remaining after degradation treatment, in mg·L. -1 .
[0062] The degradation rate test results of different catalytic materials are shown in Table 1: Table 1 .
[0063] Analysis: As shown in Table 1, calcination temperature has a significant impact on the degradation performance of kiln slag-based Fe2O3 / C catalytic materials. As the calcination temperature increases from 900℃ to 1500℃, the SF6 degradation efficiency gradually increases, reaching a maximum of 63.99% at 1500℃. This is because: high-temperature calcination promotes the in-situ recombination reaction between iron oxides and residual carbon within the kiln slag, forming a more stable Fe2O3 / C nanocomposite structure; simultaneously, high temperature helps eliminate impurities and defects in the kiln slag, improving the electron transport efficiency of the material and thus enhancing its activation ability for SF bonds in SF6 molecules. Therefore, the optimal calcination temperature is 1500℃.
[0064] Example 5
[0065] This embodiment mainly focuses on the preparation of Ag-supported kiln slag-based Fe2O3 / C catalytic material, and the steps are as follows: (1) Prepare kiln slag-based Fe2O3 / C catalytic material according to the method of Example 1.
[0066] (2) Take the above-mentioned kiln slag-based Fe2O3 / C catalyst and mix it with Ag powder. Based on the total mass of the mixed materials, control the loading of Ag element to be 5 wt%. After preliminary grinding and mixing in a mortar, transfer it to a ball mill, control the ball-to-material ratio to be 10:1, and ball mill at 300 rpm for 1 h to obtain Ag-loaded kiln slag-based Fe2O3 / C catalyst, labeled as 5 wt% Ag-Fe2O3 / C.
[0067] Example 6
[0068] The preparation method is the same as in Example 5, except that the loading of Ag element is controlled to be 1wt%, and Ag-loaded kiln slag-based Fe2O3 / C catalytic material is obtained, which is labeled as 1wt% Ag-Fe2O3 / C.
[0069] Example 7
[0070] The preparation method is the same as in Example 5, except that the loading of Ag element is controlled to be 3wt%, and Ag-loaded kiln slag-based Fe2O3 / C catalyst material is obtained, which is labeled as 3wt% Ag-Fe2O3 / C.
[0071] Example 8
[0072] The preparation method is the same as in Example 5, except that the loading of Ag element is controlled to be 7wt%, and Ag-loaded kiln slag-based Fe2O3 / C catalytic material is obtained, which is labeled as 7wt% Ag-Fe2O3 / C.
[0073] Example 9
[0074] The preparation method is the same as in Example 5, except that the loading of Ag element is controlled to be 10wt%, and Ag-loaded kiln slag-based Fe2O3 / C catalyst material is obtained, which is labeled as 10wt% Ag-Fe2O3 / C.
[0075] Application Example 2 The Ag-supported kiln slag-based Fe2O3 / C catalytic materials prepared in Examples 5-9 were applied to the degradation process of sulfur hexafluoride to test their catalytic performance.
[0076] The degradation equipment and process steps are the same as in Application Example 1.
[0077] The degradation rates of SF6 by kiln slag-based Fe2O3 / C catalytic materials with different Ag loadings are shown in Table 2.
[0078] Table 2 .
[0079] Analysis: As shown in Table 2, the Ag loading has a significant non-linear effect on catalytic performance. When the Ag loading increases from 1 wt% to 5 wt%, the SF6 degradation efficiency gradually improves, reaching a maximum of 60.20% at 5 wt%. However, when the Ag loading exceeds 5 wt%, the degradation efficiency decreases. This is because an appropriate amount of Ag can promote electron transfer and inhibit carrier recombination on the Fe2O3 / C support surface, but excessive Ag will aggregate, covering the original active sites of the Fe2O3 / C support, hindering the contact between SF6 molecules and the core catalytic center, and increasing charge transfer resistance, leading to a decrease in catalytic performance. Therefore, in Ag-loaded kiln slag-based Fe2O3 / C catalytic materials, the optimal Ag loading is 5 wt%.
[0080] Application Example 3 This embodiment mainly investigates the effect of different degradation temperatures on the catalytic performance of kiln slag-based Fe2O3 / C catalytic materials.
[0081] Catalytic materials: The catalytic material Fe2O3 / C prepared in Example 1 and the catalytic material 5wt% Ag-Fe2O3 / C prepared in Example 5 were selected.
[0082] The degradation process equipment and steps are the same as in Application Example 1, except that the degradation temperatures were adjusted to 400℃, 450℃, 500℃, 550℃ and 600℃ respectively, and the SF6 degradation efficiency of the two catalysts mentioned above at different temperatures was tested. The results are shown in Table 3.
[0083] Table 3 .
[0084] Analysis: As shown in Table 3, at all test temperatures, the SF6 degradation efficiency of the Fe2O3 / C catalyst was higher than that of the 5wt%Ag-Fe2O3 / C catalyst. The performance difference was even more significant in the medium-low temperature range of 400℃-500℃. At 600℃, the degradation efficiency of Fe2O3 / C was 63.99%, still 3.79% higher than that of 5wt%Ag-Fe2O3 / C. (Combined...) Figure 8 Performance curves and Figure 9 The Arrhenius curve shows that Fe2O3 / C has a lower activation energy, making the catalytic reaction easier to occur. This result proves that the Fe2O3 / C catalytic material of this invention can achieve better degradation performance without loading precious metals, which not only reduces catalyst costs but also avoids problems such as precious metal agglomeration and poisoning, making it more suitable for large-scale practical applications.
[0085] Application Example 4 This embodiment mainly examines the stability of the catalytic material Fe2O3 / C.
[0086] Using the catalytic material Fe2O3 / C prepared in Example 1, the SF6 degradation stability was tested continuously for 12 h according to the test equipment and process steps of Application Example 1.
[0087] Test results showed that in the initial stage of the reaction (0-3 h), the degradation rate of SF6 was stable at 63.99%; after 6 h of reaction, the degradation rate decreased slightly to 62.1%; after 12 h of reaction, the degradation rate remained above 58.9%, only 5.09% lower than the initial value.
[0088] Analysis: After prolonged continuous reaction, the catalytic material maintained high degradation activity, demonstrating its excellent resistance to sulfur and fluoride poisoning. This is attributed to the stability of the Fe2O3 / C nanocomposite structure: the carbon component effectively inhibits the aggregation of Fe2O3 active sites and fluoride deposition, while simultaneously acting as an electron transport channel to promote rapid electron transfer during the reaction. The tight interfacial bonding between Fe2O3 and graphite carbon further enhances the structural stability of the material and extends its catalytic lifespan.
[0089] Summarize: 1. The kiln slag-based Fe2O3 / C catalytic material of the present invention uses the kiln slag of zinc smelting rotary kiln as raw material. It can be prepared by a simple process of pretreatment, high-temperature calcination and ball milling without the need to add additional active components or carbon sources. The process is simple and low-cost, and at the same time realizes the high-value utilization of industrial solid waste, which is in line with the concept of circular economy.
[0090] 2. The kiln slag-based Fe2O3 / C catalytic material of the present invention can efficiently degrade SF6 under air atmosphere and normal pressure conditions without the need for inert gas protection. The reaction conditions are highly consistent with the actual atmospheric environment. At the same time, its performance is superior to that of precious metal supported materials, and it has significant environmental benefits, economic benefits and potential practical application capabilities.
Claims
1. A method for preparing a kiln slag-based Fe2O3 / C catalytic material, characterized in that, Includes the following steps: (1) Pretreatment: The zinc smelting rotary kiln slag is pretreated to obtain kiln slag raw material with uniform particle size; (2) Calcination: The kiln slag pretreated in step (1) is calcined at 900℃~1500℃ for 1-4 hours in air or a weak oxidizing atmosphere, and then cooled. (3) Ball milling: The cooled kiln slag in step (2) is ball milled to obtain powdered kiln slag-based Fe2O3 / C catalyst.
2. The method for preparing a kiln slag-based Fe2O3 / C catalytic material according to claim 1, characterized in that: In step (1): the kiln slag contains the following composition by mass fraction: Fe≥30%, Ca≤10%, Si≤5%, Zn≤5%, C≥15%, and total impurity content≤10%.
3. The method for preparing a kiln slag-based Fe2O3 / C catalytic material according to claim 1, characterized in that: In step (1): the pretreatment includes crushing and screening. The crushing is to crush the kiln slag to a particle size ≤10mm. The screening is to pass the crushed material through a 10-50 mesh sieve to obtain kiln slag raw material with uniform particle size.
4. The method for preparing a kiln slag-based Fe2O3 / C catalytic material according to claim 1, characterized in that: In step (2): the calcination is carried out in an air atmosphere.
5. The method for preparing a kiln slag-based Fe2O3 / C catalytic material according to claim 1, characterized in that: In step (2): the calcination temperature is 1500℃, the time is 2 hours, and the heating rate is 15℃·min. -1 .
6. The method for preparing a kiln slag-based Fe2O3 / C catalytic material according to claim 1, characterized in that: In step (3): the ball milling is carried out in a ball mill, using agate balls as the grinding medium, with a ball-to-material ratio of 5-15:1, a rotation speed of 100-300 rpm, and a time of 15-60 minutes.
7. The method for preparing a kiln slag-based Fe2O3 / C catalytic material according to claim 6, characterized in that: The ball milling process involved a ball-to-material ratio of 10:1, a rotation speed of 200 rpm, and a time of 30 minutes.
8. The method for preparing a kiln slag-based Fe2O3 / C catalytic material according to claim 1, characterized in that: The prepared powdered kiln slag-based Fe2O3 / C catalyst material was mixed with metallic Ag powder in a certain proportion, and then ball-milled to obtain Ag-loaded kiln slag-based Fe2O3 / C catalyst material; the Ag loading amount, based on the total mass of the mixed material, was 1 wt% to 10 wt%.
9. The application of a kiln slag-based Fe2O3 / C catalytic material prepared according to any one of claims 1-8 in the catalytic degradation of sulfur hexafluoride, characterized in that: Using kiln slag-based Fe2O3 / C catalytic material as a catalyst, sulfur hexafluoride was catalytically degraded under normal pressure and air atmosphere.
10. The application of the kiln slag-based Fe2O3 / C catalytic material according to claim 9 in the catalytic degradation of sulfur hexafluoride, characterized in that, Includes the following steps: (1) A sulfur hexafluoride mixed gas is introduced into a reactor containing kiln slag-based Fe2O3 / C catalyst material. The mixed gas consists of sulfur hexafluoride and air, wherein the volume concentration of sulfur hexafluoride is 5% to 20%. (2) Heat the reactor to 400℃~600℃ to carry out the catalytic degradation reaction; (3) The exhaust gas after step (2) is treated with an alkaline solution.