Method for coupling and trapping carbon dioxide through negative pressure roasting of vanadium slag and calcium carbonate

Abstract

The invention belongs to the technical field of resource recovery, and relates to a vanadium slag calcium carbonate negative pressure roasting coupling carbon dioxide trapping method, which comprises: S1, mixing vanadium slag and limestone according to a preset ratio, crushing to a preset particle size, mixing, and pressing into balls; s2, negative-pressure roasting is conducted in a closed furnace, and in the roasting process, a mode of external heating through dividing wall heat exchange is adopted, and roasted clinker and carbon dioxide are obtained; and S3, the roasted clinker is subjected to normal-pressure sulfuric acid leaching, and an intermediate product vanadium-containing solution is obtained after leaching. The method has the beneficial effects that negative-pressure limestone roasting is carried out in the closed furnace, the normal-pressure calcification roasting temperature is reduced by 100-300 DEG C, the roasting energy consumption is reduced, the roasting cost is reduced, and the leaching rate gt of vanadium is reduced; 90%. Meanwhile, carbon dioxide is enriched in a dividing wall heat exchange mode through external heating, a high-concentration carbon dioxide product is obtained, and value-added utilization of carbon dioxide is achieved.

Description

Technical Field

[0001] This invention relates to the field of resource recycling technology, and in particular to a method for capturing carbon dioxide by coupling negative pressure roasting of vanadium slag and calcium carbonate. Background Technology

[0002] In the iron and steel metallurgy industry, vanadium-titanium magnetite is an important mineral resource, and the smelting process generates vanadium slag, a solid waste. Vanadium slag contains a large amount of vanadium that has not been fully extracted and utilized, as well as many other metals of significant value. If these metal resources can be effectively recycled and utilized, it will not only reduce resource waste but also bring considerable economic value.

[0003] However, traditional vanadium slag treatment methods generally reveal a series of problems that urgently need to be addressed. First, from a cost perspective, traditional treatment processes often involve complex procedures and expensive equipment. For example, some processes require chemical reactions under high temperature and pressure, which not only consumes a large amount of energy but also requires significant investment in maintaining the equipment, resulting in high overall treatment costs. Second, in terms of environmental protection, these treatment methods are prone to causing secondary pollution. Some treatment processes generate wastewater, waste gas, or waste residue containing large amounts of harmful substances. If not properly treated, these pollutants can cause serious damage to environmental elements such as soil, water sources, and air. For example, if vanadium-containing wastewater is discharged directly without effective treatment, the vanadium content in surrounding water bodies will exceed standards, posing a potential threat to aquatic life and human health; if harmful gases in the waste gas are released into the atmosphere, they will exacerbate air pollution and cause environmental problems such as acid rain.

[0004] More importantly, most traditional treatment methods struggle to achieve true zero emissions. Throughout the process, some valuable metals are not fully recovered and are ultimately discarded with the waste, resulting in a significant waste of resources. Simultaneously, the direct release of incompletely treated waste into the environment further exacerbates the burden on the ecosystem and poses a severe challenge to sustainable development. Therefore, there is an urgent need to develop a more efficient, environmentally friendly, and economical method for treating vanadium slag to address the problems of high cost, secondary pollution, and resource waste inherent in existing technologies. This method would enable the full recovery and utilization of valuable metals from vanadium slag, achieving true zero emissions, protecting the ecological environment, and promoting the sustainable development of the industry. This is not only an urgent need for technological upgrading within the industry but also an inevitable choice in response to national energy conservation, emission reduction, and green development policies. Summary of the Invention

[0005] Technical problems to be solved

[0006] In view of the above-mentioned shortcomings and deficiencies of the prior art, the present invention provides a method for capturing carbon dioxide by negative pressure roasting of vanadium slag and calcium carbonate, which solves the technical problems of high cost, secondary pollution and resource waste in the existing vanadium slag treatment methods.

[0007] Technical solution

[0008] To achieve the above objectives, the main technical solutions adopted by the present invention include:

[0009] This invention provides a method for capturing carbon dioxide via negative pressure roasting of vanadium slag and calcium carbonate, comprising:

[0010] S1, mix vanadium slag and limestone in a preset ratio, crush them to a preset particle size, and then mix and press them into balls;

[0011] S2, negative pressure roasting is carried out in a closed furnace. During the roasting process, external heating is used to obtain roasted clinker and carbon dioxide through heat exchange through the partition wall.

[0012] S3 involves leaching the roasted clinker with sulfuric acid under normal pressure to obtain an intermediate product containing vanadium.

[0013] Optionally, vanadium slag and limestone are mixed at a calcium ratio of 0.4 to 1.2, wherein the calcium ratio is calculated as the mass ratio of CaO in limestone to V2O5 in vanadium slag.

[0014] Optionally, the vanadium slag and limestone are crushed to a size of 0.1 μm to 300 μm.

[0015] Optionally, during the negative pressure calcination process, the negative pressure parameter is controlled at 0.5 atm to 0.8 atm, the calcination temperature is controlled at 600℃ to 800℃, and the calcination time is controlled at 0.5h to 2h.

[0016] Optionally, during the heat exchange process, the volumetric content of carbon dioxide in the roasting furnace is enriched to 60%–70%, resulting in a high-concentration carbon dioxide product.

[0017] Optionally, the roasted clinker is subjected to sulfuric acid leaching under normal pressure, with a liquid-to-solid ratio of 3:1 to 5:1, a leaching temperature of 30℃ to 60℃, a sulfuric acid solution concentration of 50g / L to 150g / L, a leaching time of 1h to 3h, and a stirring speed of 300rpm to 700rpm.

[0018] Beneficial effects

[0019] The beneficial effects of this invention are as follows: This invention provides a method for capturing carbon dioxide through negative pressure roasting of vanadium slag and calcium carbonate. By roasting limestone under negative pressure in a closed furnace, the normal pressure calcination roasting temperature is reduced by 100℃ to 300℃, thus reducing roasting energy consumption and costs, and achieving a vanadium leaching rate >90%. Simultaneously, this invention uses external heating and heat exchange through partition walls to enrich carbon dioxide, obtaining a high-concentration carbon dioxide product. This achieves both effective vanadium extraction and value-added utilization of carbon dioxide, making it particularly suitable for the resource-based treatment of vanadium slag generated during vanadium-titanium magnetite smelting. Attached Figure Description

[0020] Figure 1 This is a schematic flowchart of a method for capturing carbon dioxide by negative pressure roasting of vanadium slag and calcium carbonate, provided in an embodiment of the present invention. Detailed Implementation

[0021] To better explain and facilitate understanding of the present invention, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] With the development of carbon capture, utilization, and storage (CCUS) technology, the resource utilization of carbon dioxide has become an important way to reduce carbon emissions and achieve economic benefits. Against this backdrop, developing a method that can both efficiently extract vanadium from vanadium slag and capture carbon dioxide to reduce environmental pollution is of great significance for promoting the green development of the metal smelting industry.

[0023] To better understand the above technical solutions, exemplary embodiments of the present invention will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present invention are shown in the drawings, it should be understood that the present invention can be implemented in various forms and should not be limited to the embodiments set forth herein. Rather, these embodiments are provided so that the present invention can be understood more clearly and thoroughly, and that the scope of the present invention can be fully conveyed to those skilled in the art.

[0024] Example 1

[0025] Reference Figure 1 This embodiment provides a method for capturing carbon dioxide via negative pressure roasting of vanadium slag calcium carbonate, comprising:

[0026] S1, mix vanadium slag and limestone in a preset ratio, crush them to a preset particle size, and then mix and press them into balls.

[0027] S2 is a negative pressure roasting process carried out in a closed furnace. During the roasting process, external heating is used to obtain roasted clinker and carbon dioxide through heat exchange between the partition walls.

[0028] S3 involves leaching the roasted clinker with sulfuric acid under normal pressure to obtain an intermediate product containing vanadium.

[0029] Optionally, vanadium slag and limestone are mixed at a calcium ratio of 0.4 to 1.2, wherein the calcium ratio is calculated as the mass ratio of CaO in limestone to V2O5 in vanadium slag.

[0030] Optionally, the vanadium slag and limestone are crushed to a size of 0.1 μm to 300 μm.

[0031] Optionally, during the negative pressure calcination process, the negative pressure parameter is controlled at 0.5 atm to 0.8 atm, the calcination temperature is controlled at 600℃ to 800℃, and the calcination time is controlled at 0.5h to 2h.

[0032] It can reduce the calcination temperature under normal pressure by 100℃~300℃.

[0033] Optionally, during the heat exchange process, the volumetric content of carbon dioxide in the roasting furnace is enriched to 60%–70%, resulting in a high-concentration carbon dioxide product.

[0034] High-concentration carbon dioxide products were obtained, realizing the value-added utilization of carbon dioxide.

[0035] Optionally, the roasted clinker is subjected to sulfuric acid leaching under normal pressure, with a liquid-to-solid ratio of 3:1 to 5:1, a leaching temperature of 30℃ to 60℃, a sulfuric acid solution concentration of 50g / L to 150g / L, a leaching time of 1h to 3h, and a stirring speed of 300rpm to 700rpm.

[0036] This invention utilizes a closed furnace for negative pressure limestone roasting, which optimizes the calcination environment and achieves a vanadium leaching rate >90%. Simultaneously, it lowers the atmospheric pressure calcination roasting temperature by 100℃~300℃, reducing roasting energy consumption and costs. External heating is employed to enrich carbon dioxide through indirect heat exchange, reducing harmful gas emissions. Furthermore, the high-concentration carbon dioxide can be used as a product, achieving value-added utilization of carbon dioxide.

[0037] Example 2

[0038] S1: Mixed ball pressing.

[0039] Vanadium slag and limestone are crushed to 0.1 μm, mixed with calcium at a ratio of 0.4, and the mixture is pressed into pellets to obtain pellets.

[0040] S2: Negative pressure roasting

[0041] The furnace was calcined in a closed furnace at a pressure of 0.5 atm, a temperature of 600°C, and a time of 2 hours.

[0042] S3: Leaching under normal pressure

[0043] During the sulfuric acid leaching process, the sulfuric acid solution concentration was 100 g / L, the leaching temperature was 60℃, the leaching time was 2 h, the liquid-to-solid ratio was 3:1, and the stirring speed was 300 rpm.

[0044] The roasting temperature using this method is 300℃ lower than that of atmospheric pressure calcination roasting, the volume content of the enriched carbon dioxide product is 65%, and the vanadium leaching rate in the vanadium slag is 93%.

[0045] Example 3

[0046] S1: Mixed briquetting

[0047] Vanadium slag and limestone are crushed to 50μm, mixed with calcium at a ratio of 0.6, and the mixture is pressed into pellets to obtain pellets.

[0048] S2: Negative pressure roasting

[0049] The furnace was calcined in a closed furnace at a pressure of 0.6 atm, a temperature of 650°C, and a time of 1 hour.

[0050] S3: Leaching under normal pressure

[0051] During the sulfuric acid leaching process, the sulfuric acid solution concentration was 50 g / L, the leaching temperature was 50℃, the leaching time was 2 h, the liquid-to-solid ratio was 3:1, and the stirring speed was 300 rpm.

[0052] The roasting temperature using this method is 250°C lower than that of atmospheric pressure calcination roasting, the volume content of the enriched carbon dioxide product is 67%, and the vanadium leaching rate in the vanadium slag is 94%.

[0053] Example 4

[0054] S1: Mixed briquetting

[0055] Vanadium slag and limestone are crushed to 150μm, mixed with calcium at a ratio of 0.8, and the mixture is pressed into pellets to obtain pellets.

[0056] S2: Negative pressure roasting

[0057] The furnace was calcined in a closed furnace at a pressure of 0.6 atm, a temperature of 700°C, and a time of 2 hours.

[0058] S3: Leaching under normal pressure

[0059] During the sulfuric acid leaching process, the sulfuric acid solution concentration was 150 g / L, the leaching temperature was 50℃, the leaching time was 1 h, the liquid-to-solid ratio was 5:1, and the stirring speed was 450 rpm.

[0060] The roasting temperature using this method is 300℃ lower than that of atmospheric pressure calcination roasting, the volume content of the enriched carbon dioxide product is 70%, and the vanadium leaching rate in the vanadium slag is 95%.

[0061] Example 5

[0062] S1: Mixed briquetting

[0063] Vanadium slag and limestone are crushed to 100μm, mixed with calcium at a ratio of 1.0, and the mixture is pressed into pellets to obtain pellets.

[0064] S2: Negative pressure roasting

[0065] The furnace was calcined in a closed furnace at a pressure of 0.8 atm, a temperature of 800°C, and a time of 0.5 h.

[0066] S3: Leaching under normal pressure

[0067] During the sulfuric acid leaching process, the sulfuric acid solution concentration was 150 g / L, the leaching temperature was 60℃, the leaching time was 1 h, the liquid-to-solid ratio was 4:1, and the stirring speed was 600 rpm.

[0068] The roasting temperature using this method is 100°C lower than that of atmospheric pressure calcination roasting, the volume content of the enriched carbon dioxide product is 70%, and the vanadium leaching rate in the vanadium slag is 96%.

[0069] Example 6

[0070] S1: Mixed briquetting

[0071] Vanadium slag and limestone are crushed to 300μm, mixed with calcium at a ratio of 1.2, and the mixture is pressed into pellets to obtain pellets.

[0072] S2: Negative pressure roasting

[0073] The furnace was calcined in a closed furnace at a pressure of 0.5 atm, a temperature of 750°C, and a time of 1.5 h.

[0074] S3: Leaching under normal pressure

[0075] During the sulfuric acid leaching process, the sulfuric acid solution concentration was 100 g / L, the leaching temperature was 30℃, the leaching time was 3 h, the liquid-to-solid ratio was 5:1, and the stirring speed was 500 rpm.

[0076] The roasting temperature using this method is 150°C lower than that of atmospheric pressure calcination roasting, the volume content of the enriched carbon dioxide product is 69%, and the vanadium leaching rate in the vanadium slag is 91%.

[0077] Obviously, those skilled in the art can make various modifications and variations to this invention without departing from its spirit and scope. Therefore, if these modifications and variations fall within the scope of the claims of this invention and their equivalents, then this invention should also include these modifications and variations.

[0078] Although embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those skilled in the art can make modifications, alterations, substitutions and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for capturing carbon dioxide by coupling negative pressure roasting of vanadium slag and calcium carbonate, characterized in that, include: S1, mix vanadium slag and limestone in a preset ratio, crush them to a preset particle size, and then mix and press them into balls; S2, negative pressure roasting is carried out in a closed furnace, and external heating is used to obtain roasted clinker and carbon dioxide through heat exchange through the partition wall; S3 involves leaching the roasted clinker with sulfuric acid under normal pressure to obtain an intermediate product containing vanadium.

2. The method for capturing carbon dioxide by negative pressure roasting of vanadium slag and calcium carbonate according to claim 1, characterized in that, Vanadium slag and limestone are mixed at a calcium ratio of 0.4 to 1.2, where the calcium ratio is calculated as the mass ratio of CaO in limestone to V2O5 in vanadium slag.

3. The method for capturing carbon dioxide by negative pressure roasting of vanadium slag and calcium carbonate according to claim 2, characterized in that, Vanadium slag and limestone are crushed to a size of 0.1 μm to 300 μm.

4. The method for capturing carbon dioxide by negative pressure roasting of vanadium slag and calcium carbonate according to claim 3, characterized in that, During the negative pressure calcination process, the negative pressure parameter is controlled at 0.5 atm to 0.8 atm, the calcination temperature is 600℃ to 800℃, and the calcination time is 0.5h to 2h.

5. The method for capturing carbon dioxide by negative pressure roasting of vanadium slag and calcium carbonate according to claim 4, characterized in that, During the heat exchange process, the volumetric carbon dioxide content in the roasting furnace is enriched to 60%–70%, resulting in a high-concentration carbon dioxide product.

6. The method for capturing carbon dioxide by negative pressure roasting of vanadium slag and calcium carbonate according to claim 5, characterized in that, The roasted clinker is leached with sulfuric acid under normal pressure, with a liquid-to-solid ratio of 3:1 to 5:1, a leaching temperature of 30℃ to 60℃, a sulfuric acid solution concentration of 50g / L to 150g / L, a leaching time of 1h to 3h, and a stirring speed of 300rpm to 700rpm.

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