Sodium-based desulfurization ash resource utilization method

Abstract

The invention discloses a sodium-based desulfurization ash resource utilization method which comprises the following steps: S1, accurately weighing a certain amount of sodium-based desulfurization ash and circulating water after steel slag braising treatment, and controlling the temperature of the circulating water to be higher than 40 DEG C; s2, pouring the sodium-based desulfurization ash weighed in the step S1 into circulating water, uniformly stirring to obtain a mixed solution, precipitating and filtering the mixed solution, taking supernate, and measuring the hardness of the supernate; and S3, uniformly spraying the mixed solution obtained in the step S2 to the surface of the liquid steel slag for cooling and / or adding water to braise the slag in the steel slag hot braising process. The method has the beneficial effect that the advantage of effectively recycling the sodium-based desulfurized fly ash is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of sodium-based desulfurization ash resource utilization, and in particular to a method for resource utilization of sodium-based desulfurization ash. Background Art

[0002] SDS sodium-based dry desulfurization technology is widely used in blast furnace hot blast furnaces, heating furnaces, coke ovens, and gas-fired boilers for extended desulfurization due to its advantages, such as high desulfurization efficiency, simple system, simple operation, low resistance, no secondary pollution, no need for corrosion protection, and small footprint. It effectively achieves ultra-low emissions of sulfur dioxide pollutants in Baozhan flue gas. The mechanism of action is that baking soda is ground into an ultrafine powder and sprayed into the flue gas through the SDS reactor. Under the action of the high-temperature flue gas, a chemical reaction occurs, decomposing into highly active Na2CO3 and CO2. The volume rapidly expands, becoming loose and porous, and fully mixing with the flue gas to produce a gas-solid phase reaction, thereby removing sulfur dioxide from the flue gas, and ultimately forming a sodium-based desulfurization ash composed mainly of sodium sulfate, with small amounts of sodium sulfite, sodium carbonate, and undecomposed sodium bicarbonate.

[0003] Patent CN202111208357.5 uses sodium-based desulfurization ash and vanadium-titanium magnetite to prepare V2O5 pellets, but the desulfurization ash content is too low, and the desulfurization ash cannot be used on a large scale. Patent CN202110271360.5 uses sodium-based desulfurization ash to treat acidic wastewater, but the process is too complicated and the equipment investment is large. The equipment corrodes severely due to the presence of chloride ions, and the industrial salt formation process requires a lot of heat, resulting in high input and low output. Patent CN202311597985.6 uses sodium-based desulfurization ash and water glass as steel slag modifiers to prepare modified steel slag powder, but due to the low activity of steel slag powder, low market recognition, and low desulfurization ash content, it cannot be used on a large scale, and the unreacted sodium carbonate and sodium bicarbonate in the sodium-based desulfurization ash can easily cause alkali-aggregate reaction or alkali backflow problems in the steel slag powder during application.

[0004] At present, sodium-based desulfurization process still occupies the mainstream in the steel industry. A large amount of sodium-based desulfurization ash is generated every year. However, there is a lack of effective utilization methods for sodium-based desulfurization ash. It is mainly stored or mixed with other products, which is prone to secondary pollution and other problems. Therefore, there is an urgent need to develop new resource utilization technologies. Summary of the Invention

[0005] In order to solve the above technical problems, the purpose of the present invention is to provide a method for resource utilization of sodium-based desulfurization ash, which comprises the following steps: Step S1: accurately weighing a certain amount of sodium-based desulfurization ash and circulating water after steel slag stewing, with the circulating water temperature being greater than 40°C; Step S2: pouring the sodium-based desulfurization ash weighed in Step S1 into the circulating water and stirring evenly to obtain a mixed solution, subjecting the mixed solution to precipitation and filtration treatment, taking the supernatant, and measuring the hardness of the supernatant; Step S3: evenly spraying the mixed solution obtained in Step S2 onto the surface of liquid steel slag for cooling and / or adding water to the slag during the hot stewing process of the steel slag. This method for resource utilization of sodium-based desulfurization ash has the advantage of being able to effectively utilize the sodium-based desulfurization ash as a resource.

[0006] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0007] A method for resource utilization of sodium-based desulfurization ash, comprising the following steps:

[0008] Step S1: accurately weigh a certain amount of sodium-based desulfurization ash and circulating water after steel slag slag treatment, and the circulating water temperature is greater than 40°C;

[0009] Step S2: Pour the sodium-based desulfurization ash weighed in step S1 into circulating water and stir evenly to obtain a mixed solution, precipitate and filter the mixed solution, take the supernatant, and measure the hardness of the supernatant;

[0010] Step S3: spraying the mixed solution obtained in S2 evenly onto the surface of the liquid slag for cooling and / or adding water to the slag during the hot stewing process of the slag.

[0011] Preferably, in step S3, the following steps are further included:

[0012] The mixed solution is used for any one or more slag treatment processes including roller crushing process, slag skimming and water cooling process, pool-type hot slag stewing process and pressurized hot slag stewing process.

[0013] Preferably, in step S3, the following steps are further included:

[0014] The mixed solution is used in the pool-type hot slag stewing process, which lasts 10-12 hours. The amount of liquid steel slag processed by a slag stewing pool is 180t, and the water injection volume is 30-40t / h. During the slag stewing operation, all the water evaporates in the first 4 hours.

[0015] Preferably, in step S3, the following steps are further included:

[0016] The mixed solution is used in the autoclave slag-making process, which takes 2-3 hours. The amount of steel slag processed by a slag-making tank is 30 tons, and the amount of water pumped is 1 t / ton·slag.

[0017] Preferably, in step S1, the following steps are further included:

[0018] The sodium-based desulfurization ash is the desulfurization ash discharged from the desulfurization system of a power plant or a coking plant. The sodium sulfate content in the sodium-based desulfurization ash is greater than 90% (including sodium sulfite), and the alkalinity (sodium carbonate, sodium bicarbonate) is greater than 1% (calculated as calcium carbonate).

[0019] Preferably, in step S1, the following steps are further included:

[0020] The circulating water after the steel slag stewing treatment is the circulating water with a temperature greater than 40° C. obtained by collecting the steel slag through the circulation system during the steel slag stewing process after the steel slag gradually cools and the water no longer evaporates.

[0021] Preferably, in step S2, the following steps are further included:

[0022] 0.1 to 50 parts by weight of sodium-based desulfurization ash are added to 10 to 100 parts by weight of steel slag slag treated circulating water, and the mixture is mixed and stirred to obtain a mixed solution.

[0023] Preferably, in step S2, the following steps are further included:

[0024] The mass fraction of sodium sulfate is 0.9% to 30%, and the mass fraction of sodium carbonate or sodium bicarbonate is 0.1% to 5%.

[0025] Preferably, in step S2, the following steps are further included:

[0026] The mass fraction of sodium sulfate is 10% to 20%.

[0027] Preferably, in step S1, the following steps are further included:

[0028] Accurately weigh the sodium-based desulfurization ash using a belt scale and put it into the circulating water pool;

[0029] In step S2, the following steps are also included:

[0030] After the sodium-based desulfurization ash is fully dissolved in the circulating water, the mixed solution is transported through a pipeline.

[0031] Compared with the prior art, the present invention has achieved beneficial technical effects:

[0032] 1. Use the circulating water after the steel slag is treated for dissolution. Taking advantage of the fact that the circulating water temperature is greater than 40°C, it helps to increase the solubility of sodium sulfate without the need for additional heat, and fully utilizes the heat of the circulating water.

[0033] 2. Sodium-based desulfurization ash dissolves in circulating water, which helps reduce the calcium hardness of circulating water, reduces the risk of pipeline scaling, and extends the life of pipelines and valves.

[0034] 3. The sodium sulfate mixed solution penetrates into the steel slag through water cooling, slag stewing and other methods, which can form sulfate excitation and form calcium vanadium during the hydration process of the steel slag, increasing the density of the structure and helping to improve the activity of the steel slag.

[0035] 4. It achieves the advantage of being able to effectively utilize sodium-based desulfurization ash as a resource, effectively reduces the storage cost of sodium-based desulfurization ash, reduces the risk of environmental pollution when storing sodium-based desulfurization ash, and avoids direct mixing with other products and causing pollution to other products. DETAILED DESCRIPTION

[0036] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the embodiments, but the scope of protection claimed in the present invention is not limited to the following specific embodiments.

[0037] A method for resource utilization of sodium-based desulfurization ash, comprising the following steps:

[0038] Step S1: Accurately weigh a certain amount of sodium-based desulfurization ash and circulating water after steel slag stewing treatment, and the circulating water temperature is greater than 40°C; the sodium-based desulfurization ash is the desulfurization ash discharged from the desulfurization system of a power plant or a coking plant, and the sodium sulfate content in the sodium-based desulfurization ash is greater than 90% (including sodium sulfite), and the alkalinity (sodium carbonate, sodium bicarbonate) is greater than 1% (calculated as calcium carbonate). The circulating water after the steel slag stewing treatment is the circulating water with a temperature greater than 40°C obtained by collecting the steel slag through the circulation system during the steel slag stewing process, after the slag gradually cools down. Accurately weigh the sodium-based desulfurization ash using a belt scale and put it into the circulating water pool.

[0039] Step S2: Pour the sodium-based desulfurization ash weighed in step S1 into circulating water and stir evenly to obtain a mixed solution. The mixed solution is precipitated and filtered, and the supernatant is collected and the hardness of the supernatant is measured. 0.1 to 50 parts by weight of sodium-based desulfurization ash is placed in 10 to 100 parts by weight of circulating water after steel slag slag treatment, and the mixture is stirred evenly to obtain a mixed solution containing sodium sulfate. The mass fraction of sodium sulfate is 0.9% to 30%. In this embodiment, the mass fraction of sodium sulfate is 10% to 20%. The mass fraction of sodium carbonate or sodium bicarbonate is 0.1% to 5%. After the sodium-based desulfurization ash is fully dissolved in the circulating water, the mixed solution is transported through a pipeline.

[0040] Step S3: Spray the mixed solution obtained in S2 evenly onto the surface of the liquid slag for cooling and / or water injection during the hot slag stewing process. The mixed solution is used in the roller crushing process, the slag skimming and water injection cooling process, the pool-type hot slag stewing process, and the pressurized hot slag stewing process. The mixed solution is used in the pool-type hot slag stewing process. The pool-type hot slag stewing process lasts 10-12 hours. The amount of liquid slag processed by a slag stewing pool is 180t, and the amount of water injected is 30-40t / h. During the slag stewing operation, all the water evaporates in the first 4 hours. The mixed solution is used in the pressurized hot slag stewing process. The pressurized hot slag stewing process lasts 2-3 hours. The amount of slag processed by a slag stewing tank is 30t, and the amount of water injected is 1t / ton·slag.

[0041] Continuous tests were conducted to detect the calcium hardness of the circulating water before and after the test and the scaling of the circulating water delivery pipeline. The activity index of the steel slag after treatment with the mixed solution was also detected. The test data are shown in Table 1.

[0042] Table 1 Test data of calcium hardness of circulating water and 28-day activity index of steel slag under different mass fractions of sodium sulfate

[0043]

[0044] It can be seen from the above test data that with the increase of the mass fraction of sodium sulfate, the calcium hardness of the circulating water shows a downward trend, and the 28-day activity index of the steel slag continues to increase. However, with the increase of the amount of sodium-based desulfurization ash, the circulating water temperature drops seriously and the solubility of sodium sulfate decreases. Therefore, it is more appropriate to control the mass fraction of sodium sulfate in the range of 10% to 20%. Within this range, the calcium hardness of the circulating water decreases, and the 28-day activity index of the steel slag increases rapidly.

[0045] This embodiment has the following advantages:

[0046] The slag is dissolved in circulating water after being treated by stewing steel slag. The characteristic of circulating water temperature being greater than 40°C helps to increase the solubility of sodium sulfate without the need for additional heat, making full use of the heat of circulating water.

[0047] Sodium-based desulfurization ash dissolves in circulating water, which helps reduce the calcium hardness of circulating water, reduces the risk of pipeline scaling, and extends the life of pipelines and valves.

[0048] The sodium sulfate mixed solution penetrates into the steel slag through water cooling, slag stewing and other methods, which can form sulfate excitation and form calcium vanadium during the hydration process of the steel slag, increasing the density of the structure and helping to improve the activity of the steel slag.

[0049] The advantage of being able to effectively utilize the sodium-based desulfurization ash as a resource is achieved, effectively reducing the sodium-based desulfurization ash that needs to be stored, thereby reducing the storage cost generated by storing the sodium-based desulfurization ash, and reducing the risk of environmental pollution when storing the sodium-based desulfurization ash, and avoiding the pollution to other products caused by direct mixing with other products.

[0050] Based on the disclosure and teachings of the above description, those skilled in the art may also make changes and modifications to the above embodiments. Therefore, the present invention is not limited to the specific embodiments disclosed and described above, and any modifications and variations of the invention should also fall within the scope of protection of the claims of the present invention. In addition, although certain specific terms are used in this description, these terms are for convenience of description only and do not constitute any limitation to the invention.

Claims

1. A method for resource utilization of sodium-based desulfurization ash, characterized in that: The following steps are involved: Step S1: accurately weigh a certain amount of sodium-based desulfurization ash and circulating water after steel slag slag treatment, and the circulating water temperature is greater than 40°C; Step S2: Pour the sodium-based desulfurization ash weighed in step S1 into circulating water and stir evenly to obtain a mixed solution, precipitate and filter the mixed solution, take the supernatant, and measure the hardness of the supernatant; Step S3: spraying the mixed solution obtained in S2 evenly onto the surface of the liquid slag for cooling and / or adding water to the slag during the hot stewing process of the slag.

2. The method for resource utilization of sodium-based desulfurization ash according to claim 1, characterized in that: In the step S3, the following steps are also included: The mixed solution is used for any one or more slag treatment processes including roller crushing process, slag skimming and water cooling process, pool-type hot slag stewing process and pressurized hot slag stewing process.

3. The method for resource utilization of sodium-based desulfurization ash according to claim 2, characterized in that: In the step S3, the following steps are also included: The mixed solution is used in the pool-type hot slag stewing process, which lasts 10-12 hours. The amount of liquid steel slag processed by a slag stewing pool is 180t, and the water injection volume is 30-40t / h. During the slag stewing operation, all the water evaporates in the first 4 hours.

4. The method for resource utilization of sodium-based desulfurization ash according to claim 2, characterized in that: In the step S3, the following steps are also included: The mixed solution is used in the autoclave slag-making process, which takes 2-3 hours. The amount of steel slag processed by a slag-making tank is 30 tons, and the amount of water pumped is 1 t / ton·slag.

5. The method for resource utilization of sodium-based desulfurization ash according to claim 1, characterized in that: In the step S1, the following steps are also included: The sodium-based desulfurization ash is the desulfurization ash discharged from the desulfurization system of a power plant or a coking plant. The sodium sulfate content in the sodium-based desulfurization ash is greater than 90% (including sodium sulfite), and the alkalinity (sodium carbonate, sodium bicarbonate) is greater than 1% (calculated as calcium carbonate).

6. The method for resource utilization of sodium-based desulfurization ash according to claim 5, characterized in that: In the step S1, the following steps are also included: The circulating water after the steel slag stewing treatment is the circulating water with a temperature greater than 40° C. obtained by collecting the steel slag through the circulation system during the steel slag stewing process after the steel slag gradually cools and the water no longer evaporates.

7. The method for resource utilization of sodium-based desulfurization ash according to claim 6, characterized in that: In step S2, the following steps are also included: 0.1 to 50 parts by weight of sodium-based desulfurization ash are added to 10 to 100 parts by weight of steel slag slag treated circulating water, and the mixture is mixed and stirred to obtain a mixed solution.

8. The method for resource utilization of sodium-based desulfurization ash according to claim 7, characterized in that: In step S2, The following steps are involved: The mass fraction of sodium sulfate is 0.9% to 30%, and the mass fraction of sodium carbonate or sodium bicarbonate is 0.1% to 5%.

9. The method for resource utilization of sodium-based desulfurization ash according to claim 8, characterized in that: In step S2, the following steps are also included: The mass fraction of sodium sulfate is 10% to 20%.

10. The method for resource utilization of sodium-based desulfurization ash according to claim 1, characterized in that: In the step S1, the following steps are also included: Accurately weigh the sodium-based desulfurization ash using a belt scale and put it into the circulating water pool; In step S2, the following steps are also included: After the sodium-based desulfurization ash is fully dissolved in the circulating water, the mixed solution is transported through a pipeline.

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