Method for improving carbon sequestration rate of aod stainless steel slag

Abstract

The application discloses a method for improving carbon fixation rate of AOD stainless steel slag. The method comprises the following steps: slagging: the stainless steel slag in an AOD furnace is discharged, the steel slag is poured into a slag tank, and a tank cover is covered; natural cooling: the AOD stainless steel slag in the slag tank is naturally cooled; carbonation reaction: a spray valve on the slag tank is opened, the cooled AOD stainless steel slag is sprayed with water, a flue gas valve at the bottom of the slag tank is opened, CO2-containing flue gas is introduced, and the AOD stainless steel slag is subjected to acidification reaction with the CO2-containing flue gas; detection: after the acidification reaction is completed, a sample is taken from the slag tank, thermogravimetric analysis is carried out, and it is detected that the AOD stainless steel slag loses 4% to 12% at 500 DEG C to 800 DEG C, namely, the carbon fixation rate of the AOD stainless steel slag is 4% to 12%, the content of f-CaO in the stainless steel slag is effectively reduced, waste gas rich in CO2 in a steel plant can be disposed of in cooperation with the steel slag, and the carbon emission reduction level is effectively improved.

Description

Technical Field

[0001] This invention belongs to the field of metallurgical technology, and in particular relates to a method for improving the carbon fixation rate of AOD stainless steel slag. Background Technology

[0002] Stainless steel slag is a solid waste generated during the stainless steel smelting process, and its main chemical components are CaO, SiO2, Al2O3, and MgO. Stainless steel slag includes AOD (Alkali Oxide) stainless steel slag and electric furnace stainless steel slag. AOD stainless steel slag is characterized by small particle size, large specific surface area, and high calcium content, with a calcium oxide content exceeding 50%, classifying it as a high-alkalinity steel slag. These characteristics indicate that the theoretical carbon fixation capacity of AOD stainless steel slag is higher than that of ordinary steel slag. However, current technologies for treating AOD stainless steel slag result in a carbon fixation rate of only about 0.7% to 1.6%, leading to a low carbon fixation rate and severely impacting carbon emission reduction levels. Summary of the Invention

[0003] To address some or all of the technical problems existing in the prior art, the present invention provides a method for improving the carbon fixation rate of AOD stainless steel slag.

[0004] The method of the present invention for improving the carbon fixation rate of AOD stainless steel slag includes the following steps:

[0005] S1. Slag Removal: Stainless steel slag is removed from the AOD furnace. The slag is poured into the slag pot and the pot lid is closed.

[0006] S2. Natural cooling: The AOD stainless steel slag in the slag pot is cooled naturally;

[0007] S3, Carbonation reaction: Open the spray valve on the slag pot to spray water on the cooled AOD stainless steel slag, and at the same time open the flue gas valve at the bottom of the slag pot to introduce CO2 flue gas, so that the AOD stainless steel slag and CO2 flue gas can undergo an acidification reaction.

[0008] S4. Testing: After the acidification reaction is completed, a sample is taken from the slag pot and subjected to thermogravimetric analysis. The results show that the AOD stainless steel slag loses 4% to 12% of its weight in the 500℃ to 800℃ range, which is the carbon fixation rate of the AOD stainless steel slag of 4% to 12%.

[0009] Furthermore, in the above-mentioned method for improving the carbon fixation rate of AOD stainless steel slag, during the S1 slag discharge process, when the steel slag is poured into the slag pot, it is necessary to ensure that the steel slag is in a liquid high-temperature state.

[0010] Furthermore, in the above-mentioned method for improving the carbon fixation rate of AOD stainless steel slag, the AOD stainless steel slag is naturally cooled to 200±10℃ during the cooling process.

[0011] Furthermore, in the above-mentioned method for improving the carbon fixation rate of AOD stainless steel slag, the amount of water sprayed onto the cooled AOD stainless steel slag during the carbonation reaction is 10% to 30%.

[0012] Furthermore, in the above-mentioned method for improving the carbon fixation rate of AOD stainless steel slag, the CO2 content in the flue gas is ≥10% during the carbonation reaction process, and the carbonation reaction time is 1-12h.

[0013] The method for improving the carbon fixation rate of AOD stainless steel slag according to the present invention has the following advantages and beneficial effects:

[0014] This invention effectively improves the carbon fixation rate of AOD stainless steel slag. By using high-temperature AOD stainless steel slag for natural cooling, the f-CaO content in the slag can be reduced, and the performance of the steel slag can be effectively improved. At the same time, it can achieve the co-treatment of CO2-rich waste gas and steel slag within the steel plant, effectively improving the carbon emission reduction level. Detailed Implementation

[0015] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below in conjunction with specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0016] The method of the present invention for improving the carbon fixation rate of AOD stainless steel slag includes the following steps:

[0017] S1. Slag Removal: Stainless steel slag is removed from the AOD furnace. The slag is poured into the slag pot and the pot lid is closed.

[0018] S2. Natural cooling: The AOD stainless steel slag in the slag pot is cooled naturally;

[0019] S3, Carbonation reaction: Open the spray valve on the slag pot to spray water on the cooled AOD stainless steel slag, and at the same time open the flue gas valve at the bottom of the slag pot to introduce CO2 flue gas, so that the AOD stainless steel slag and CO2 flue gas can undergo an acidification reaction.

[0020] S4. Testing: After the acidification reaction is completed, a sample is taken from the slag pot and subjected to thermogravimetric analysis. The results show that the AOD stainless steel slag loses 4% to 12% of its weight in the 500℃ to 800℃ range, which is the carbon fixation rate of the AOD stainless steel slag of 4% to 12%.

[0021] The formula for calculating carbon fixation rate is:

[0022]

[0023] in: Indicates: AOD stainless steel slag carbon fixation rate; m 0 Indicates: Original weight of stainless steel slag; m 1 This indicates the weight of stainless steel slag after it has undergone carbonation reaction by spraying water through CO2-containing flue gas and then drying.

[0024] Furthermore, in the method for improving the carbon fixation rate of AOD stainless steel slag of the present invention, during the slag discharge process of S1, when the steel slag is poured into the slag pot, it is necessary to ensure that the steel slag is in a liquid high-temperature state.

[0025] Furthermore, in the method for improving the carbon fixation rate of AOD stainless steel slag of the present invention, the AOD stainless steel slag is naturally cooled to 200±10℃ during the cooling process.

[0026] Furthermore, in the method for improving the carbon fixation rate of AOD stainless steel slag of the present invention, during the carbonation reaction process, the amount of water sprayed onto the cooled AOD stainless steel slag is 10% to 30%, which is beneficial for carbon fixation.

[0027] Furthermore, in the method for improving the carbon fixation rate of AOD stainless steel slag of the present invention, during the carbonation reaction process, the CO2 content in the flue gas is ≥10%, and the carbonation reaction time is 1-12h.

[0028] Example 1

[0029] This invention includes the following steps:

[0030] S11: Slag discharge from the AOD furnace for stainless steel smelting. The high-temperature AOD slag flows into the slag pot. After the slag is discharged, the slag pot lid is closed.

[0031] S12: AOD stainless steel slag is naturally cooled to 196°C in the slag pot;

[0032] S13: Open the spray valve on the slag pot lid to spray water on the cooled AOD stainless steel slag, open the flue gas valve at the bottom of the slag pot, and introduce flue gas containing 30% CO2 to allow the AOD stainless steel slag to react with the flue gas for 10 hours.

[0033] S14: The carbon fixation rate of AOD stainless steel slag was tested. After the carbonation reaction was completed, a sample was taken from the slag pot for thermogravimetric analysis. The thermogravimetric analysis results showed that the AOD stainless steel slag lost 7.1% of its weight in the 550-800℃ range, which means that the carbon fixation rate of AOD stainless steel slag was 7.1%.

[0034] The comparison includes the following steps:

[0035] S11: Slag discharge from the AOD furnace for stainless steel smelting. The high-temperature AOD slag flows into the slag pot. After the slag is discharged, the slag pot lid is closed.

[0036] S12: AOD stainless steel slag is cooled to 196°C in the slag pot by spraying water.

[0037] S13: Open the flue gas valve at the bottom of the slag pot and introduce flue gas containing 30% CO2 to allow the AOD stainless steel slag to react with the flue gas for 10 hours.

[0038] S14: The carbon fixation rate of AOD stainless steel slag was tested. After the carbonation reaction was completed, a sample was taken from the slag pot for thermogravimetric analysis. The thermogravimetric analysis results showed that the AOD stainless steel slag lost 0.9% of its weight in the 550-800℃ range, that is, the carbon fixation rate of AOD stainless steel slag was 0.9%.

[0039] Compared with the comparative example, the carbon fixation rate of the AOD stainless steel slag in the invention example is significantly improved.

[0040] Example 2

[0041] This invention includes the following steps:

[0042] S21: Slag discharge from the AOD furnace for stainless steel smelting. The high-temperature AOD slag flows into the slag pot. After the slag is discharged, the slag pot lid is closed.

[0043] S22: AOD stainless steel slag is naturally cooled to 204°C in the slag pot;

[0044] S23: Open the spray valve on the slag pot lid to spray water on the cooled AOD stainless steel slag, open the flue gas valve at the bottom of the slag pot, and introduce flue gas containing 40% CO2 to allow the AOD stainless steel slag to react with the flue gas for 7 hours.

[0045] S24: The carbon fixation rate of AOD stainless steel slag was tested. After the carbonation reaction was completed, a sample was taken from the slag pot for thermogravimetric analysis. The thermogravimetric analysis results showed that the AOD stainless steel slag lost 6.8% of its weight in the 550-800℃ range, that is, the carbon fixation rate of AOD stainless steel slag was 6.8%.

[0046] The comparison includes the following steps:

[0047] S21: Slag discharge from the AOD furnace for stainless steel smelting. The high-temperature AOD slag flows into the slag pot. After the slag is discharged, the slag pot lid is closed.

[0048] S22: AOD stainless steel slag is cooled to 204°C in the slag pot by spraying water.

[0049] S23: Open the flue gas valve at the bottom of the slag pot and introduce flue gas containing 40% CO2 to allow the AOD stainless steel slag to react with the flue gas for 7 hours.

[0050] S24: The carbon fixation rate of AOD stainless steel slag was tested. After the carbonation reaction was completed, a sample was taken from the slag pot for thermogravimetric analysis. The thermogravimetric analysis results showed that the AOD stainless steel slag lost 0.8% of its weight in the 550-800℃ range, that is, the carbon fixation rate of AOD stainless steel slag was 0.8%.

[0051] Compared with the comparative example, the carbon fixation rate of the AOD stainless steel slag in the invention example is significantly improved.

[0052] Example 3

[0053] This invention includes the following steps:

[0054] S31: Slag discharge from the AOD furnace for stainless steel smelting. The high-temperature AOD slag flows into the slag pot. After the slag is discharged, the slag pot lid is closed.

[0055] S32: AOD stainless steel slag is naturally cooled to 200°C in the slag pot;

[0056] S33: Open the spray valve on the slag pot lid to spray water on the cooled AOD stainless steel slag, open the flue gas valve at the bottom of the slag pot to introduce flue gas containing 99.9% CO2, and let the AOD stainless steel slag react with the flue gas for 12 hours to carbonize.

[0057] S34: The carbon fixation rate of AOD stainless steel slag was tested. After the carbonation reaction was completed, a sample was taken from the slag pot for thermogravimetric analysis. The thermogravimetric analysis results showed that the AOD stainless steel slag lost 12% of its weight in the 550-800℃ range, that is, the carbon fixation rate of AOD stainless steel slag was 12%.

[0058] The comparison includes the following steps:

[0059] S31: Slag discharge from the AOD furnace in stainless steel smelting. The high-temperature AOD slag flows into the slag pot, and after slag discharge, it is covered.

[0060] Slag container lid;

[0061] S32: AOD stainless steel slag is cooled to 200°C in the slag pot by spraying water.

[0062] S33: Open the flue gas valve at the bottom of the slag pot and introduce flue gas containing 99.9% CO2 to allow the AOD stainless steel slag to react with the flue gas for 12 hours.

[0063] S34: The carbon fixation rate of AOD stainless steel slag was tested. After the carbonation reaction was completed, a sample was taken from the slag pot for thermogravimetric analysis. The thermogravimetric analysis results showed that the AOD stainless steel slag lost 1.6% of its weight in the 550-800℃ range, which means that the carbon fixation rate of AOD stainless steel slag was 1.6%.

[0064] Compared with the comparative example, the carbon fixation rate of the AOD stainless steel slag in the invention example is significantly improved.

[0065] In summary, compared with the prior art, the method of the present invention for improving the carbon fixation rate of AOD stainless steel slag has the following advantages and beneficial effects:

[0066] This invention effectively improves the carbon fixation rate of AOD stainless steel slag. By using high-temperature AOD stainless steel slag for natural cooling, the f-CaO content in the slag can be reduced, and the performance of the steel slag can be effectively improved. At the same time, it can achieve the co-treatment of CO2-rich waste gas and steel slag within the steel plant, effectively improving the carbon emission reduction level.

[0067] It should be noted that, unless otherwise expressly specified and limited, the term "connection" or its synonyms should be interpreted broadly in this document. For example, "connection" can be a fixed connection or a detachable connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be the internal communication of two elements or the interaction between two elements. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances. Furthermore, expressions such as "first" and "second" are merely used to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. At the same time, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus.

[0068] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for improving the carbon fixation rate of AOD stainless steel slag, characterized in that, The method for improving the carbon fixation rate of AOD stainless steel slag includes the following steps: S1. Slag Removal: Stainless steel slag is removed from the AOD furnace. The slag is poured into the slag pot and the pot lid is closed. S2. Natural cooling: The AOD stainless steel slag in the slag pot is cooled naturally; S3, Carbonation reaction: Open the spray valve on the slag pot to spray water on the cooled AOD stainless steel slag, and at the same time open the flue gas valve at the bottom of the slag pot to introduce CO2 flue gas, so that the AOD stainless steel slag and CO2 flue gas can undergo an acidification reaction. S4. Testing: After the acidification reaction is completed, samples are taken from the slag pot for thermogravimetric analysis. The results show that the AOD stainless steel slag loses 4% to 12% of its weight in the 500℃~800℃ range, which is the carbon fixation rate of the AOD stainless steel slag of 4% to 12%. During the slag removal process, when the steel slag is poured into the slag pot, it must be ensured that the steel slag is in a liquid, high-temperature state. During the cooling process, the AOD stainless steel slag is naturally cooled to 200±10℃; During the carbonation reaction, the amount of water sprayed onto the cooled AOD stainless steel slag is 10%~30%; During the carbonation reaction, the CO2 content in the flue gas is ≥10%, and the carbonation reaction time is 1-12 hours.

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