A dry method for treating soda ash desulfurization ash

Abstract

The present invention discloses a dry method for treating soda ash desulfurization ash. It comprises the following steps: S1, stirring and dissolving white sulfur-fixing ash and water; S2, filtering; S3, adjusting the pH of the filtrate, heating, and introducing the produced gas into saturated lime water to obtain a bleaching agent; S4, adding sodium hydroxide solution to the solution in S3 to adjust the pH; S5, performing precipitation, stirring, standing, and filtering on the solution in S4 to obtain upper substances and lower clear liquid, transferring the upper substances into an autoclave, and reserving the lower clear liquid; S6, adding appropriate amount of distilled water into the autoclave, adjusting the concentration, adding aluminum sulfate and sulfonated melamine, and after the reaction is completed, drying the product to obtain α-hemihydrate gypsum; S7, adding ethanol to the lower clear liquid in S5, stirring, standing, filtering, and drying to obtain industrial salt; S8, heating the filtrate in S7, and volatilizing all the ethanol to obtain sodium hydroxide solution. This method does not produce secondary pollution, and some substances are recycled, which can save resources.

Description

Technical Field

[0001] The invention relates to the technical field of comprehensive resource utilization of dry desulfurization ash solid waste, and in particular to a method for treating dry baking soda desulfurization ash. Background Art

[0002] SO 2 The realization of emission reduction mainly depends on the development of desulfurization technology. 2 The main emission measures include: desulfurization of raw materials and fuels, desulfurization during combustion, and desulfurization after combustion (flue gas desulfurization). Among them, only flue gas desulfurization has been commercialized on a large scale. There are more than a dozen flue gas desulfurization processes, which can be roughly divided into three categories: wet, dry, and semi-dry according to whether water needs to be added during desulfurization and the dry and wet state of desulfurization by-products.

[0003] The wet desulfurization process has the advantages of high desulfurization efficiency and high utilization rate of desulfurizer, but it also has large investment and high operating costs. In actual application, there are also disadvantages such as high investment and operation costs, easy agglomeration and clogging, and serious equipment corrosion. The desulfurizer of the dry desulfurization process is in dry powder form, and the desulfurization by-product is also in powder form. The entire desulfurization process is simple, and the equipment operation investment is lower than that of traditional wet flue gas desulfurization. However, the desulfurization efficiency and effective utilization rate of the dry desulfurization process are lower than those of the wet desulfurization process. The semi-dry desulfurization process not only has the characteristics of the dry desulfurization process, but also has the advantages of traditional wet technology. Its desulfurization by-product is also in dry powder form, which is easier to handle, the process is relatively simple, the utilization rate of the desulfurizer is higher than that of the dry desulfurization process, and the investment is lower than that of the traditional wet desulfurization process. At present, it is gradually favored by small and medium-sized steel or power plants in China.

[0004] Studies have shown that NaHCO 3 It has good desulfurization effect, wide source, low price, and is considered to be an ideal semi-dry desulfurizer. Desulfurization ash is a by-product of semi-dry flue gas desulfurization in steel enterprises. A large amount of desulfurization ash is piled up and stored due to its complex composition and cannot be well utilized. This patent is aimed at a large amount of steel plant desulfurization ash stored in scientific process treatment to obtain various pure substances. The pure products can be recycled, thus completely solving the problem of desulfurization ash polluting the surrounding ecological environment. From the domestic patents CN202210623597.X and CN202111366464.0, CN202110038944.8, all three patents are oxidized after being dissolved in water, and then concentrated, crystallized, and separated to obtain NaSO4·10H2O, resulting in high input costs, low output value, and the mother liquor needs to be discarded to produce secondary pollution. Concentration and crystallization require a lot of energy and cannot be commercialized. Summary of the invention

[0005] The purpose of the present invention is to provide a dry baking soda desulfurization ash treatment method to solve the problems of high cost, low output value, secondary pollution caused by the need to discard the mother liquor, and large amount of energy consumption for concentrated crystallization in the prior art.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for treating dry baking soda desulfurization ash, comprising the following steps:

[0008] S1. Add the weighed white solid sulfur ash into a glass container, add distilled water in a ratio of 1:8-10, stir until the white solid is completely dissolved, and let stand;

[0009] S2, filtering the obtained solution through a filter screen, collecting the upper impurities after drying, and cooling the obtained lower clear liquid for later use;

[0010] S3, in above-mentioned clear liquid, add hydrochloric acid, adjust pH to 3-4, then heat solution, if solution is yellow, continue to be heated until yellow disappears, collect the gas generated and pass into saturated lime water, dry and obtain bleaching agent, if solution presents colorless, enter next step operation;

[0011] S4, gradually adding sodium hydroxide solution to the obtained solution to adjust the pH;

[0012] S5. Add a precipitant of white sulfur-fixing ash to the above solution, stir the resulting solution, let it stand, filter it through a filter, transfer the resulting upper material into an autoclave, and cool the lower clear liquid for later use;

[0013] S6, adding an appropriate amount of distilled water to the autoclave, adjusting the material concentration, adding aluminum sulfate and sulfonated melamine, leaving for a period of time, heating the autoclave solution, taking out the product and drying it to obtain α-hemihydrate gypsum;

[0014] S7, adding the lower clear liquid to the ethanol solution, stirring the resulting solution, letting it stand, filtering it through a circular filter to obtain an upper substance and a filtrate, and drying the obtained upper substance to obtain industrial salt;

[0015] S8, adding porcelain pieces to the obtained filtrate, continuing to heat up to evaporate all the ethanol, obtaining a sodium hydroxide solution, the ethanol is recycled into step S7 for use, part of the sodium hydroxide solution is added to step S4, and the excess part is dried to obtain solid caustic soda flakes.

[0016] Furthermore, in step S1, the capacity of the glass container is 1 L, the temperature of the distilled water is 10-20° C., the stirring time is 30 min, the rotation speed is 50-100 r / min, and the standing time is 1 h-2 h.

[0017] Furthermore, in step S2, the filter screen is a 30 μm circular filter screen, and the obtained lower clear liquid is cooled to 10-12° C.

[0018] Furthermore, in step S3, the volume of the clear liquid is 100-150 ml, the mass of the hydrochloric acid is 2-3 g, the concentration is 1+10 to 1+9, the temperature when the solution is heated is 100-105° C., and the concentration of the saturated lime water is 2-2.5 g / l.

[0019] Furthermore, in step S4, the concentration of the sodium hydroxide solution is 5%-7%, and the pH is adjusted to 3-4.

[0020] Furthermore, in step S5, the precipitant is 0.3-0.4 g of a calcareous alkaline substance, and the calcareous alkaline substance includes carbide slag, quicklime, and slaked lime. The stirring is performed at a speed of 40-80 r / min for 30 min, and the standing time is 30-50 min. The filter is a 45 μm circular filter, and the cooling temperature is 10°C.

[0021] Furthermore, in step S6, the material concentration is 0.75%-1.2%, the mass of aluminum sulfate and sulfonated melamine added is 0.08%-0.1% of the material in the autoclave, and the mixture is placed at 20-25° C. for 24 hours, and the autoclave solution is heated to 110-120° C. for 5 hours to 7 hours.

[0022] Furthermore, in step S7, the volume fraction of ethanol is 90%-95%, the resulting solution is stirred at a speed of 20-30 r / min for 10 min, and allowed to stand for 30-60 min, and the filter is a 15 μm circular filter.

[0023] Furthermore, in step S8, 3-5 g of ceramic chips are added to the obtained filtrate, and the temperature is raised to 80-90°C.

[0024] Furthermore, the drying temperature is between 100-105°C.

[0025] Based on the above technical solution, the embodiments of the present invention can at least produce the following technical effects:

[0026] (1) The process involves multiple filtrations, and each filtration can produce an effective substance;

[0027] (2) Taking full account of the performance fluctuations of industrial waste, the performance of sulfur ash fixed by some methods is stable, and some steps can be omitted;

[0028] (3) The state of the obtained substances in the process is fully considered, and the substances are purified according to their state, thus saving energy to the greatest extent;

[0029] (4) The process does not emit any substances, does not produce secondary pollution, all substances can be sold, has the greatest economic value, the process is simple, the logic is clear, and is suitable for the large-scale treatment of industrial solid waste;

[0030] (5) Some materials in the process are recycled and no high-value materials need to be added, so the process is highly feasible. DETAILED DESCRIPTION

[0031] The present invention provides a dry baking soda desulfurization ash treatment method, comprising the following steps:

[0032] S1. Add the weighed white solid sulfur ash into a glass container, add distilled water in a ratio of 1:8-10, stir until the white solid is completely dissolved, and let stand;

[0033] S2, filtering the obtained solution through a filter screen, collecting the upper impurities after drying, and cooling the obtained lower clear liquid for later use;

[0034] S3, in above-mentioned clear liquid, add hydrochloric acid, adjust pH to 3-4, then heat solution, if solution is yellow, continue to be heated until yellow disappears, collect the gas generated and pass into saturated lime water, dry and obtain bleaching agent, if solution presents colorless, enter next step operation;

[0035] S4, gradually adding sodium hydroxide solution to the obtained solution to adjust the pH;

[0036] S5. Add a precipitant of white sulfur-fixing ash to the above solution, stir the resulting solution, let it stand, filter it through a filter, transfer the resulting upper material into an autoclave, and cool the lower clear liquid for later use;

[0037] S6, adding an appropriate amount of distilled water to the autoclave, adjusting the material concentration, adding aluminum sulfate and sulfonated melamine, leaving for a period of time, heating the autoclave solution, taking out the product and drying it to obtain α-hemihydrate gypsum;

[0038] S7, adding the lower clear liquid to the ethanol solution, stirring the resulting solution, letting it stand, filtering it through a circular filter to obtain an upper substance and a filtrate, and drying the obtained upper substance to obtain industrial salt;

[0039] S8, adding porcelain pieces to the obtained filtrate, continuing to heat up to evaporate all the ethanol, obtaining a sodium hydroxide solution, the ethanol is recycled into step S7 for use, part of the sodium hydroxide solution is added to step S4, and the excess part is dried to obtain solid caustic soda flakes.

[0040] The chemical composition of the solid sulfur ash is shown in Table 1

[0041] Table 1 Chemical composition of sulfur-fixing ash

[0042]

[0043] Embodiment 1:

[0044] S1. Add the weighed white solid sulfur ash into a 1L glass container, add 10-20℃ distilled water in a ratio of 1:8-10, stir at 50-100r / min for 30min, let stand for 1h-2h, and observe whether the white solid is completely dissolved. If not, continue stirring until the white solid is completely dissolved.

[0045] S2. The obtained solution is passed through a 30 μm circular filter, the upper impurities are dried and collected, and the obtained lower clear liquid is cooled to 10° C.-12° C. for use.

[0046] S3, add 2-3g of hydrochloric acid with a concentration of (1+10-1+9) to 100-150ml of solution, adjust the pH to 3-4; heat the solution to 100-105℃, if the solution is yellow, continue heating until the yellow disappears, collect the gas on the top of the container and pass it into a saturated lime water solution with a concentration of 2-2.5g / l, dry it to obtain a bleaching agent. If the solution is colorless, proceed to the next step;

[0047] S4, gradually adding 5%-7% sodium hydroxide solution to the obtained solution, and adjusting the pH value to 6.5-7.5;

[0048] S5. Take the above solution and add 0.3-0.4g of white sulfur-fixing ash precipitant, which is a calcareous alkaline substance such as carbide slag, quicklime, slaked lime, etc. Stir the resulting solution at a speed of 40-80r / min for 30min, let it stand for 30-50min, filter it through a 45μm circular filter, transfer the upper material into an autoclave, and cool the resulting lower clear liquid to 10°C for standby use;

[0049] S6, add an appropriate amount of distilled water to the autoclave, adjust the material concentration to 0.75%-1.2%, add 0.08%-0.1% of the total amount of the above substances, aluminum sulfate and sulfonated melamine, place at 20°C-25°C for 24 hours, heat the autoclave solution to 110-120°C for 5h-7h, take out and dry at 100-105°C to obtain α-hemihydrate gypsum;

[0050] S7, adding the lower clear liquid into 90%-95% ethanol, stirring the resulting solution at a speed of 20-30 r / min for 10 min, standing for 30-60 min, filtering through a 15 μm circular filter, and drying the resulting substance at 100-105° C. to obtain industrial salt;

[0051] S8, add 3-5g of porcelain chip to the obtained filtrate, continue to heat up to 80℃-90℃, make the anhydrous ethanol evaporate completely, obtain sodium hydroxide solution, ethanol is recycled to be used in step S7, part of sodium hydroxide solution is added to step S4, and the excess part is dried to obtain solid caustic soda flakes.

[0052] Example 2

[0053] S1. Add the weighed white sulfur-fixing ash into 1m 3 In a room temperature low-pressure stainless steel reactor, add 10~20℃ distilled water in a ratio of 1:8, stir at a speed of 50~100r / min for 30min, let it stand for 1h~2h, and observe whether the white solid is completely dissolved. If not, continue stirring until the white solid is completely dissolved.

[0054] S2. The obtained solution is passed through a circular membrane filter with a mesh size of 550 meshes, the upper impurities are dried and collected, and the obtained lower clear liquid is cooled to 10°C-12°C for use.

[0055] S3. Add 2-3kg of hydrochloric acid with a concentration of (10%-20%) to the obtained lower clear liquid, adjust the pH to 3-4; heat the solution to 100-105°C. If the solution is yellow, continue heating until the yellow disappears. Collect the gas in the upper part of the container and pass it into a saturated lime water solution with a concentration of 2-2.5g / l, and dry it to obtain a bleaching agent. If the solution is colorless, proceed to the next step;

[0056] S4, gradually adding 5% to 7% sodium hydroxide solution to the obtained solution, and adjusting the pH value to 6.5-7.5;

[0057] S5. Take the above solution and add 0.3-0.4 kg of white sulfur-fixing ash precipitant, which is a calcareous alkaline substance such as carbide slag, quicklime, slaked lime, etc. Stir the resulting solution at a speed of 40-80 r / min for 30 min, let it stand for 30-50 min, pass it through a circular vacuum precision filter with a mesh of 300 mesh, transfer the upper material to an autoclave, and cool the resulting lower clear liquid to 10°C for standby use;

[0058] S6, add an appropriate amount of distilled water to the autoclave, adjust the material concentration to 0.75%-1.2%, add 0.08%-0.1% of the total amount of the above substances, aluminum sulfate and sulfonated melamine, place at 20°C-25°C for 24 hours, heat the autoclave solution to 110-120°C for 6 hours, take out and dry at 100-105°C to obtain α-hemihydrate gypsum;

[0059] S7, adding the lower clear liquid into 95% ethanol, stirring the resulting solution at a speed of 20-30 r / min for 10 min, standing for 30-60 min, passing through a spherical precision filter with a mesh size of 950, and drying the resulting substance at 100-105°C to obtain industrial salt;

[0060] S8, add 3-5kg of porcelain chips to the obtained filtrate, continue to heat up to 80℃-90℃, make the anhydrous ethanol evaporate completely, and obtain sodium hydroxide solution, the ethanol is recycled to be used in step S7, part of the sodium hydroxide solution is added to step S4, and the excess part is dried to obtain solid caustic soda flakes.

Claims

1. A dry process for treating soda ash desulfurization ash, characterized in that, it includes the following steps: S1. Add the weighed white sulfur-fixing ash into a glass container, add distilled water according to a ratio of 1:8 - 10, stir until the white solid is completely dissolved, and let it stand; S2. Filter the obtained solution through a filter screen, dry and collect the upper impurities, and cool and reserve the lower clear liquid obtained; S3. Add hydrochloric acid to the above clear liquid, adjust the pH to 3 - 4, then heat the solution. If the solution shows yellow, continue heating until the yellow color disappears, collect the generated gas and pass it into saturated lime water, dry to obtain a bleaching agent. If the solution is colorless, proceed to the next step; S4. Gradually dropwise add sodium hydroxide solution to the obtained solution to adjust the pH; S5. Add a precipitant of white sulfur-fixing ash to the above solution, stir, let it stand, and filter through a filter screen. Transfer the upper substance obtained to an autoclave, cool and reserve the lower clear liquid. The precipitant is 0.3 - 0.4 g of calcium-based alkaline substance. The calcium-based alkaline substance includes carbide slag, quicklime, and slaked lime. Stir at a speed of 40 - 80 r / min for 30 min, and the standing time is 30 - 50 min. The filter screen is a 45-μm circular filter screen, and the cooling temperature is 10°C; S6. Add an appropriate amount of distilled water to the autoclave, adjust the material concentration, add aluminum sulfate and sulfonated melamine, let it stand for a period of time, then heat the solution in the autoclave, take out the product and dry it to obtain α-hemihydrate gypsum. The material concentration is 0.75% - 1.2%, and the mass of aluminum sulfate and sulfonated melamine added is 0.08% - 0.1% of the substances in the autoclave. Let it stand at 20 - 25°C for 24 h, and heat the solution in the autoclave to 110 - 120°C for 5 - 7 h; S7. Add the lower clear liquid to an ethanol solution, stir the obtained solution, let it stand, and filter through a circular filter screen to obtain the upper substance and the filtrate. Dry the upper substance obtained to obtain industrial salt; S8. Add porcelain chips to the obtained filtrate, continue to raise the temperature to volatilize all the ethanol to obtain a sodium hydroxide solution. The ethanol is recycled and reused in step S7. Part of the sodium hydroxide solution is added to step S4, and the excess part is dried to obtain solid caustic soda flakes.

2. A dry process for treating soda ash desulfurization ash according to claim 1, characterized in that, in step S1, the capacity of the glass container is 1 L, the temperature of the distilled water is 10 - 20°C, the stirring time is 30 min, the rotation speed is 50 - 100 r / min, and the standing time is 1 - 2 h.

3. A dry process for treating soda ash desulfurization ash according to claim 1, characterized in that, in step S2, the filter screen is a 30-μm circular filter screen, and the lower clear liquid obtained is cooled to 10 - 12°C.

4. A dry process for treating soda ash desulfurization ash according to claim 1, characterized in that, in step S3, the volume of the clear liquid is 100 - 150 ml, the mass of the hydrochloric acid is 2 - 3 g, the concentration is 1 + 10~1 + 9, the temperature during heating the solution is 100 - 105°C, and the concentration of the saturated lime water is 2 - 2.5 g / l.

5. A dry process for treating soda ash desulfurization ash according to claim 1, characterized in that, in step S4, the concentration of the sodium hydroxide solution is 5%-7%, and the pH is adjusted to 3-4.

6. A dry process for treating soda ash desulfurization ash according to claim 1, characterized in that, in step S7, the volume fraction of ethanol is 90%-95%, the obtained solution is stirred at a speed of 20-30 r / min for 10 min, allowed to stand for 30-60 min, and the filter screen is a 15-μm circular filter screen.

7. A dry process for treating soda ash desulfurization ash according to claim 1, characterized in that, in step S8, 3-5 g of porcelain chips are added to the obtained filtrate, and the temperature is raised to 80-90 °C.

8. A dry process for treating soda ash desulfurization ash according to claim 1, characterized in that, the drying temperature is 100-105 °C.

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