Red mud-based mercury removal sulfur material, preparation thereof and application thereof in simultaneous removal of mercury and sulfur dioxide in flue gas

Abstract

The present application belongs to the field of waste gas treatment, and particularly relates to a preparation method of a red mud-based mercury and sulfur removal material. A solution containing red mud, a carbonate, a selenium source, an additive and an auxiliary agent is modified by aging, and then solid-liquid separation is performed to obtain the red mud-based mercury and sulfur removal material. The auxiliary agent includes at least one of ferric chloride, ferrous sulfate and polyferric sulfate. The present application also includes the red mud-based mercury and sulfur removal material prepared by the preparation method and the application of the material in mercury and sulfur removal. The carbonate, the selenium source, the additive and the auxiliary agent are used to modify the red mud innovatively, so that the characteristics of the red mud can be fully utilized, the network structure and the active sites of the adsorption material can be synergistically endowed and optimized, and the exposure characteristics of the active sites can be improved, thereby improving the simultaneous removal effect of the prepared red mud-based material on sulfur dioxide and mercury.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of environmental protection and resource comprehensive utilization, and particularly relates to a red mud-based composite material for purifying flue gas and a preparation and application thereof. BACKGROUND

[0002] Red mud is an alkaline solid waste produced in the process of alumina production. The cumulative amount of red mud in the world has exceeded 4 billion tons, which has caused serious pollution to the natural environment and also wasted resources. Red mud can cause dust pollution, reduce visibility, damage the ecological environment, and cause air pollution. The alkaline elements in red mud can cause soil salinization, which is not conducive to plant growth and is difficult to reclaim. The high alkalinity and high fluoride content of red mud leachate can pollute groundwater and affect the ecological structure. The red mud pile has the risk of dam break, which threatens safety, seriously wastes land resources, and causes environmental and economic losses. The comprehensive utilization of red mud is a difficult problem that needs to be solved in the alumina industry, and it is of great significance to realize the comprehensive utilization of red mud resources. Red mud has small particle size, high porosity, good dispersibility, high specific surface area, high iron oxide content, and high flocculation, so the red mud particles have a certain adsorption capacity for heavy metal ions and can be used as potential adsorbent materials in the field of pollution control. In addition, the high alkalinity of red mud has the potential to be used as an alkaline neutralizing agent, which can be applied to processes such as flue gas desulfurization.

[0003] The control of pollutants in flue gas is another prominent environmental problem faced by today's society. Sulfur dioxide emitted into the air can easily react with water vapor, oxygen and other chemicals to form acidic substances such as sulfuric acid, leading to the production of acid rain. Acid rain has great destructive nature to soil and water ecosystems, can change the acid-base balance of soil, and affect crop growth; sulfur dioxide inhaled can harm the respiratory system of the human body; sulfur dioxide is further converted into fine particulate matter (PM2.5), thereby exacerbating smog weather. Mercury and its compounds have the characteristics of high toxicity, high corrosiveness, high volatility, biological enrichment, and easy migration and diffusion. When mercury enters the atmosphere, it enters the soil and water through sedimentation or precipitation circulation and is converted into methylmercury by microorganisms, affecting the survival of fish, birds and mammals and endangering the ecological system; methylmercury can cause damage to the central nervous system, leading to nerve damage, delayed mental development, and memory loss; gaseous mercury can cause damage to the kidneys and lungs, and long-term exposure increases the risk of cancer.

[0004] However, most of the existing red mud-based treatment materials are developed for single mercury vapor or sulfur dioxide, and there are few technologies that can simultaneously and efficiently treat sulfur dioxide and mercury vapor in flue gas under mild conditions. For example, the Chinese patent document with publication number CN118179245A discloses a preparation method of an alkaline absorbent for simultaneously removing SO3 and mercury in coal-fired flue gas. The alkaline residue, carbide slag and red mud are mixed and then immersed in a halide salt solution, stirred and mixed uniformly, and then dried and calcined. After cooling to room temperature, the calcined product is obtained. Finally, grinding is performed to obtain the product. This technology is used for the simultaneous removal of SO3 and mercury heavy metals, but it is difficult to adapt to the simultaneous removal of SO2 and mercury. In addition, the removal process needs to be carried out at a high temperature, and the simultaneous removal effect is not ideal at low temperature. For another example, the Chinese patent document with publication number CN108722143A discloses a dry purification device and process capable of achieving ultra-low emission of flue gas. This technology can remove SO2, NOx, mercury and the like, but needs to rely on special equipment, and the technical universality is not ideal.

[0005] In summary, the existing technology still lacks a red mud-based treatment material that can efficiently utilize the characteristics of red mud and simultaneously and efficiently remove mercury and sulfur dioxide under mild conditions. SUMMARY

[0006] In order to change the problem of red mud accumulation and the difficulty of existing red mud-based treatment materials in simultaneously and efficiently removing sulfur dioxide and mercury in flue gas under mild conditions, the present application innovatively provides a preparation method of a red mud-based mercury and sulfur removal material, which aims to fully utilize the characteristics of red mud and prepare a treatment material that can simultaneously and efficiently remove sulfur dioxide and mercury in flue gas.

[0007] The second object of the present application is to provide the red mud-based mercury and sulfur removal material prepared by the preparation method and its application in adsorbing sulfur dioxide and mercury vapor in flue gas.

[0008] Existing red mud-based materials can achieve good results in adsorbing and removing sulfur dioxide or mercury vapor alone, but when adsorbing sulfur dioxide and mercury vapor simultaneously, they will compete for adsorption sites, thereby interfering with the simultaneous removal effect of sulfur dioxide and mercury vapor, especially under mild adsorption conditions. The influence of this mutual competition and interference will be further amplified. In view of this problem, the present application provides the following improved scheme after in-depth research:

[0009] A preparation method of a red mud-based mercury and sulfur removal material, which comprises the steps of: preparing a solution containing red mud, carbonate, selenium source, additive and auxiliary agent; and performing aging modification on the solution, followed by solid-liquid separation to obtain the red mud-based mercury and sulfur removal material.

[0010] The auxiliary agent comprises at least one of ferric chloride, ferrous sulfate and polymeric ferric sulfate.

[0011] In view of the problem that it is difficult to simultaneously adsorb mercury and sulfur dioxide due to the physicochemical characteristics of red mud, the red mud is modified by the carbonate, selenium source, additive and auxiliary agent in the application, so that the characteristics of the red mud can be fully utilized, the network structure and active site of the adsorption material can be synergistically endowed and optimized, and the exposure characteristics of the active site can be improved, thereby improving the simultaneous removal effect of the prepared red mud-based material on sulfur dioxide and mercury. The research of the application shows that the prepared material can be applied to the simultaneous removal of sulfur dioxide and mercury in different adsorption scenes such as solid-phase method and liquid-phase method, and good simultaneous removal effect of sulfur dioxide and mercury can be obtained under relatively low temperature and low alkali conditions. In addition, the material utilization rate is excellent, the red mud can be efficiently disposed, and the material cost can be effectively reduced.

[0012] In the application, the red mud can be a red mud waste known in the industry, for example, it can be derived from at least one of the Bayer process, the sintering process and the combined process red mud in the alkali method alumina production.

[0013] In the application, the carbonate includes at least one of sodium bicarbonate, calcium bicarbonate, sodium carbonate, calcium carbonate and magnesium carbonate. The research of the application shows that, unlike other alkaline components, the carbonate used in the application can further synergistically optimize the microstructure and active site of the prepared material in combination with other components, and can further improve the simultaneous removal effect of the prepared red mud-based material on sulfur dioxide and mercury.

[0014] In the application, the selenium source includes at least one of selenium dioxide, selenite and selenate.

[0015] In the application, the additive includes at least one of thiosulfate and GSH.

[0016] In the application, the additive is 0.5-1.5 times the weight of the selenium source.

[0017] In the application, the above material components can be mixed based on any step. For example, in one implementable manner of the application, the red mud and the carbonate are mixed in advance to obtain a mixed material A; the selenium source and the additive are dispersed in a solution to obtain an activation mother liquor; then the mixed material A, the activation mother liquor and the auxiliary agent are mixed for aging modification, followed by solid-liquid separation to obtain a red mud-based mercury and sulfur removal material.

[0018] In the application, the activation mother liquor further contains fine selenium powder seeds with a particle size of more than 400 mesh. Under the preferred process, the simultaneous removal efficiency and effect of sulfur dioxide and mercury of the prepared material can be further optimized.

[0019] Preferably, the amount of fine selenium powder seeds is 1%-20% of the weight of the selenium source, and further can be 4-15%.

[0020] In the present application, the auxiliary agent and the combined control of the auxiliary agent type can adapt to the physicochemical characteristics of red mud, can be combined with other processes and components, and is helpful to synergistically impart and construct the three-dimensional structure and sites of the prepared material, thereby helping to improve the simultaneous removal effect of red mud-based material on sulfur dioxide and mercury.

[0021] In the present application, the weight ratio of red mud to carbonate is 75-95:5-25, and further can be 80-92:8-20.

[0022] The selenium source is 1-10 wt.% of the weight of the red mud, and further can be 2-6 wt.%.

[0023] The auxiliary agent is 0.2-8% of the weight of the red mud, preferably 1-6%.

[0024] Preferably, the aging modification time is more than 0.5 h, and further can be 1-2 h.

[0025] In the present application, the red mud-based mercury and sulfur removal material is granulated to obtain a granular red mud-based mercury and sulfur removal material.

[0026] The present application also provides a red mud-based mercury and sulfur removal material prepared by the preparation method.

[0027] The present application research shows that the preparation method can impart special physicochemical characteristics to the prepared material, and the product of the characteristics can obtain excellent simultaneous removal effect of sulfur dioxide and mercury under mild conditions.

[0028] The present application also provides a red mud-based mercury and sulfur removal material for simultaneous removal of sulfur dioxide and mercury in flue gas.

[0029] In the present application, the red mud-based mercury and sulfur removal material can be used as an adsorbent based on conventional adsorption means for the removal of sulfur dioxide and mercury in flue gas. For example, the removal method is dry adsorption or wet adsorption.

[0030] In the present application, the temperature of the removal stage is 20-200°C. The process of the present application can realize efficient simultaneous removal of sulfur dioxide and mercury under mild conditions.

[0031] Principle and advantage

[0032] The red mud material has the characteristics of small particle size, large porosity, good dispersing performance, high specific surface area, high iron oxide content and high flocculation. The active ingredient is combined with the red mud material by simple modification. Due to the high flocculation and high dispersion of the red mud material, a small amount of active ingredient can be uniformly distributed on the red mud base. The adsorption, flocculation, acid-base neutralization and other abilities of the red mud are improved by modification. The red mud-based composite material has rich adsorption sites, and these sites are fully exposed during the modification process, increasing the contact probability with pollutants. The alkali base and carbonate radical groups in the red mud-based composite material can react with sulfur dioxide and water in the flue gas to fix and remove sulfur dioxide. When the red mud-based composite material enters the slurry, the high alkalinity of the red mud has the potential to be used as an alkaline neutralizing agent, which can effectively reduce the amount of alkali in the desulfurization system. The selenium active sites, oxygen sites and metal sites in the red mud-based composite material synergistically form stable selenium-oxygen-mercury compounds to fix mercury.

[0033] Compared with the prior art, the advantages of the technical scheme of the present application are as follows:

[0034] (1) The environmental problems caused by the large accumulation of solid waste red mud and flue gas pollutants are simultaneously alleviated, waste is treated with waste, waste is turned into treasure, and green and sustainable development is realized.

[0035] (2) The process is simple, no fine synthesis is needed, it is beneficial to large-scale production, the application range is wide, and it can be applied to various types of red mud.

[0036] (3) Low cost, using almost cost-free and large stock red mud as base material.

[0037] (4) Environmentally friendly, no secondary pollution, avoiding the environmental problems in the process of using chemical raw materials and reagents for fine synthesis, and having great environmental benefits.

[0038] (5) The amount of alkali in the desulfurization system can be reduced, and the cost of overall flue gas purification can be reduced.

[0039] (6) High efficiency of flue gas pollutant purification, which can achieve deep removal. BRIEF DESCRIPTION OF DRAWINGS

[0040] Figure 1 Schematic diagram of powder composite material sprayed in the flue;

[0041] Figure 2 Schematic diagram of granular composite material applied in the fixed bed. DETAILED DESCRIPTION

[0042] The technical scheme of the present application is further described below through specific examples. The examples are not a limitation on the scope of protection.

[0043] The preparation method of the red mud-based composite material is as follows:

[0044] (1) Red mud is dried at room temperature, then carbonates additives are added, mixed and dried at 90-150 DEG C, and then the mixture is ground and broken.

[0045] (2) Selenium substances are configured into a solution, appropriate solid additives are added, a small amount of fine selenium powder with a mesh size of more than 400 is added as a crystal seed, and high-speed stirring is performed to form an activated mother liquor.

[0046] (3) The activated mother liquor is diluted and added to the red mud mixture, a small amount of ferric chloride is added for aging modification, a slurry is formed, stirring is performed for 1-3 hours, and after aging, the modified red mud-based material is obtained after dehydration and drying.

[0047] (4) After being directly ground and broken, a powder red mud-based composite material is obtained; or after being appropriately broken, a certain proportion of water glass and CaO are mixed, an appropriate amount of water is sprayed, and a granular red mud-based composite material is obtained after being formed and granulated in an extruder.

[0048] The raw material red mud is obtained from Bayer process, sintering process and combined process red mud in the production of alkaline aluminum oxide.

[0049] The selenium substances include at least one of selenium dioxide, selenite and selenate.

[0050] The mass ratio of red mud to carbonates is 75-95:5-25; the solid additives are a mixture of sodium thiosulfate and GSH, the mass ratio is 1-4:1, and the addition amount of fine selenium powder crystal seed is 1%-10% of the selenium mass of selenium substances; and the addition amount of ferric chloride is 0.2-3% of the mass of the red mud mixture.

[0051] The solid additives are a mixture of sodium thiosulfate and GSH, the mass ratio is 2:1, and the addition amount of fine selenium powder crystal seed is 4%-7% of the selenium mass of selenium substances.

[0052] For the Bayer process and combined process red mud, when the granular powder red mud-based composite material is formed and granulated into a ball, the mass ratio of the modified red mud-based material, water glass, CaO and water is 87-97:0.5-4:0-6:0.5-6; and the sintering process red mud does not need to be additionally added with CaO.

[0053] The size of the granules is less than 8mm.

[0054] For the red mud with a CaO content of more than 8%, CaO is also not additionally added.

[0055] In the present application, the test method of the treated material can be conventional, for example, the powder composite material is injected into the flue gas before the flue gas dust removal device or the wet desulfurization device (such as Figure 1As shown in the figure), the powder composite material is in full gas-solid contact with the pollutants in the flue gas in the flue or the device cavity to fix and remove the mercury and sulfur dioxide in the flue gas; the powder composite material enters the desulfurization slurry of the wet desulfurization device with the flue gas, and the powder composite material is in gas-liquid-solid three-phase contact with the pollutants in the flue gas to strengthen the fixation and removal of the mercury and sulfur dioxide in the flue gas; the granular composite material is filled into the box, and the box is arranged and installed into the fixed bed (as shown in the figure). Figure 2 As shown in the figure), the granular composite material is in full gas-solid contact with the pollutants in the flue gas in the bed body to fix and remove the mercury and sulfur dioxide in the flue gas.

[0056] Preferably, the flue gas dust removal device includes an electric dust collector, a bag dust collector, a wet dust collector, etc.

[0057] Preferably, the application temperature of the powder composite material in the flue, the flue gas dust removal device and the wet desulfurization device is 25-190℃, the application temperature of the granular composite material in the fixed bed is 25-150℃, the injection amount of the powder composite material in the flue is 0.03-12g / m 3 .

[0058] The industrial flue gas pollutants are derived from non-ferrous smelting, coal-fired power plants, catalyst production, cement production, petrochemical industry, garbage treatment, natural gas industry, etc.

[0059] Example 1

[0060] 8g of the Bayer red mud with a CaO content of 14% is dried at room temperature, then 2g of carbonates (sodium carbonate) is added, mixed, dried at 100℃, and ground; 0.16g of SeO2 is dissolved in water to form a solution, 0.1g of sodium thiosulfate and 0.1g of GSH are added, then 0.02g of fine selenium powder with a mesh size of more than 400 is added as a crystal seed, and a high-speed stirring is performed to obtain an activated mother liquor; the activated mother liquor is diluted and added to the red mud mixture, then 0.16g of ferric chloride is added for aging modification to form a slurry, stirred for 1h, dehydrated after aging, dried at 105℃ for 6h, ground and broken, and then sieved through a 200 mesh sieve to obtain a powder red mud-based composite material.

[0061] 20mg of the powder red mud-based composite material is placed in a simulated fixed bed reactor, a quantitative sulfur dioxide is generated by a sulfur dioxide standard gas cylinder and a flow controller, a quantitative elemental mercury is generated by a mercury permeation tube, a flue gas analyzer and a VM-3000 mercury analyzer are used for real-time measurement of sulfur dioxide and mercury, the total gas flow is 1L / min, the initial sulfur dioxide concentration is 30ppm, and the initial mercury concentration is 50±1μg / m 3 In a temperature range of 100-190℃, the sulfur dioxide removal rate is higher than 80%, and the mercury removal efficiency is higher than 99%, which indicates that the red mud-based composite material has a significant effect on the removal of pollutants in the flue gas in a wide temperature range.

[0062] Comparative Example 1

[0063] Comparative Example 1 was repeated, except that the unmodified red mud obtained in Example 1 was used as the treating agent. The other operations and parameters were the same as in Example 1. The sulfur dioxide removal rate was 18% and the mercury removal efficiency was 5.4% at a flue gas temperature of 125°C, indicating that the unmodified red mud had little effect on the removal of pollutants in the flue gas.

[0064] Comparative Example 2

[0065] Comparative Example 1 was repeated, except that sodium hydroxide was used instead of the carbonate salt. The other operations and parameters were the same as in Example 1. The sulfur dioxide removal rate was only 42% and the mercury removal efficiency was 87% at a flue gas temperature of 150°C.

[0066] Comparative Example 3

[0067] Comparative Example 1 was repeated, except that no ferric chloride was added. The other operations and parameters were the same as in Example 1. The sulfur dioxide removal rate was 70% and the mercury removal efficiency was 72% at a flue gas temperature of 150°C.

[0068] Comparative Example 4

[0069] Comparative Example 1 was repeated, except that aluminum sulfate was used instead of the ferric chloride. The other operations and parameters were the same as in Example 1. The sulfur dioxide removal rate was 65% and the mercury removal efficiency was 71% at a flue gas temperature of 150°C.

[0070] Example 2

[0071] Comparative Example 1 was repeated, except that no selenium source and no seed crystal were added. The other operations and parameters were the same as in Example 1. The sulfur dioxide removal rate was 77% and the mercury removal efficiency was 83% at a flue gas temperature of 150°C.

[0072] Example 3

[0073] 9.2 g of the powder red mud-based composite material obtained in Example 1 and 0.3 g of water glass were mixed, and 0.5 mL of water was added dropwise to wet the mixture and mix well. The mixture was then added to an extruder to form granules, and a particle red mud-based composite material with a size of 4 mm was obtained.

[0074] The granular red mud-based composite material was filled in a simulated fixed bed reactor with a filling height of 4 cm. Quantitative sulfur dioxide was generated by a sulfur dioxide standard gas cylinder and a flow controller, and quantitative elemental mercury was generated by a mercury permeation tube. Real-time measurements of sulfur dioxide and mercury were performed using a flue gas analyzer and a VM-3000 mercury analyzer. The total gas flow was 2 L / min, the initial sulfur dioxide concentration was 100 ppm, and the initial mercury concentration was 400 ± 2 μg / m 3 At 125°C, the sulfur dioxide removal rate was higher than 75%, and the mercury removal efficiency was higher than 99.5%.

[0075] Example 4

[0076] The sintered red mud with a CaO content of 17% was dried at room temperature, then 1 g of carbonate (calcium carbonate) was added, and after mixing, it was dried at 110°C and ground. 0.52 g of sodium selenite was dissolved in water to form a solution, 0.3 g of sodium thiosulfate and 0.15 g of GSH were added, then 0.06 g of fine selenium powder with a particle size of more than 400 mesh was added as a seed crystal, and the mixture was stirred at high speed to obtain an activated mother liquor. The activated mother liquor was diluted and added to the red mud mixture, then 0.2 g of ferric chloride was added for aging modification to form a slurry, which was stirred for 1 h, then dehydrated after aging, dried at 95°C for 12 h, ground and sieved through a 200 mesh sieve to obtain a powder red mud-based composite material.

[0077] 20 mg of the powder red mud-based composite material was placed in a simulated fixed bed reactor, quantitative sulfur dioxide was generated by a sulfur dioxide standard gas cylinder and a flow controller, quantitative elemental mercury was generated by a mercury permeation tube, real-time measurements of sulfur dioxide and mercury were performed using a flue gas analyzer and a VM-3000 mercury analyzer, the total gas flow was 1 L / min, the initial sulfur dioxide concentration was 50 ppm, and the initial mercury concentration was 200 ± 2 μg / m 3 In the temperature range of 100-175°C, the sulfur dioxide removal rate was higher than 70%, and the mercury removal efficiency was higher than 98%.

[0078] The powder red mud-based composite material was sprayed into the simulated pilot platform flue, quantitative sulfur dioxide was generated by a sulfur dioxide standard gas cylinder and a flow controller, quantitative elemental mercury was generated by a mercury permeation tube, real-time measurements of sulfur dioxide and mercury were performed using a flue gas analyzer and a VM-3000 mercury analyzer, the initial sulfur dioxide concentration was 50 ppm, and the initial mercury concentration was 40 ± 1 μg / m 3 The powder red mud-based composite material was sprayed at a rate of 0.6 g / m 3 At 100°C, the sulfur dioxide removal rate was higher than 90%, and the mercury removal efficiency was higher than 99%.

[0079] Example 5

[0080] 9.2 g of Bayer process red mud with 5% CaO content was dried at room temperature, then 0.8 g of carbonate (sodium carbonate) was added, mixed, dried at 110°C, and ground; 0.45 g of SeO2 was dissolved in water to form a solution, 0.3 g of sodium thiosulfate and 0.15 g of GSH were added, then 0.02 g of fine selenium powder with a particle size of more than 400 mesh was added as a seed crystal, and the activated mother liquor was obtained by high-speed stirring; the activated mother liquor was diluted and added to the red mud mixture, then 0.5 g of ferric chloride was added for aging modification, forming a slurry, stirring for 1 h, dehydrating after aging, drying at 95°C for 12 h, grinding and sieving through a 200 mesh sieve to obtain a powder red mud-based composite material.

[0081] 9 g of powder red mud-based composite material, 0.2 g of water glass, and 0.4 g of CaO were mixed according to the mass fraction, and then 0.4 mL of water was added dropwise to wet and mix, and then added to an extruder for molding and granulation to obtain a granular red mud-based composite material with a size of 3 mm.

[0082] The granular red mud-based composite material was filled in a simulated fixed bed reactor with a filling height of 6 cm, a quantitative sulfur dioxide was generated by a sulfur dioxide standard gas cylinder and a flow controller, a quantitative mercury was generated by a mercury permeation tube, and real-time measurement of sulfur dioxide and mercury was performed using a flue gas analyzer and a VM-3000 mercury analyzer, the total gas flow was 1 L / min, the initial sulfur dioxide concentration was 100 ppm, and the initial mercury concentration was 1200±2 μg / m 3 At 125°C, the sulfur dioxide removal rate was higher than 80%, and the mercury removal efficiency was higher than 98%.

[0083] Example 6

[0084] The red mud-based composite material powder material was produced in batches according to the proportions of Example 2, and the powder material was sprayed into the gas inlet of a pilot-scale simulated wet desulfurization tower, a quantitative sulfur dioxide was generated by a sulfur dioxide standard gas cylinder and a flow controller, a quantitative mercury was generated by a mercury permeation tube, and real-time measurement of sulfur dioxide and mercury was performed using a flue gas analyzer and a VM-3000 mercury analyzer, the initial sulfur dioxide concentration was 200 ppm, and the initial mercury concentration was 200±1 μg / m 3 The powder red mud-based composite material was sprayed at a rate of 1 g / m 3 The sulfur dioxide removal rate was higher than 99%, and the mercury removal efficiency was higher than 99.5%.

[0085] When the alkali dosage in the simulated wet desulfurization tower was reduced to 70%, the sulfur dioxide removal rate was 82% without spraying the red mud-based composite material powder, and the sulfur dioxide removal rate was higher than 99% when the powder was sprayed, indicating that spraying the red mud-based composite material could reduce the amount of alkali used in the wet desulfurization tower to a certain extent.

[0086] Example 7

[0087] A field test was conducted in a certain enterprise, the flue gas amount was 3600m 3 / h, the concentration of sulfur dioxide was 30 PPM,

[0088] the concentration of mercury was 100-200μg / m 3 , about 0.6 m 3 of particle red mud-based composite material was filled into the drawer of the fixed bed (as shown in Figure 2 , the temperature of the fixed bed was 45-50℃, the removal rate of sulfur dioxide was 79%, and the removal rate of mercury was more than 98%.

[0089] The above examples are illustrative of the present application and are not limiting of the present application, any simple modification of the present application is within the protection scope of the present application.

Claims

1. A method for preparing a red mud-based mercury-sulfur removal material, characterized in that, Red mud and carbonates are mixed in advance to obtain mixture A; selenium source and additives are dispersed in solution to obtain activation mother liquor; then mixture A, activation mother liquor and auxiliaries are mixed and aged for modification, followed by solid-liquid separation to obtain red mud-based mercury desulfurization material; The carbonates mentioned include at least one of sodium bicarbonate, calcium bicarbonate, sodium carbonate, calcium carbonate, and magnesium carbonate. The selenium source includes at least one of selenium dioxide, selenite, and selenate; The additives include at least one of thiosulfate and GSH; The additive is 0.5 to 1.5 times the weight of the selenium source; The activated mother liquor also contains fine selenium powder seed crystals with a particle size of 400 mesh or larger. The auxiliary agent is ferric chloride; The weight ratio of red mud to carbonate is 75~95:5~25; The selenium source is 1-10 wt.% of the red mud weight; The additives are 0.2-8% of the weight of the red mud.

2. The preparation method of the red mud-based mercury-sulfurization material as described in claim 1, characterized in that, The red mud mentioned above is derived from at least one of the red mud produced by the Bayer process, sintering process, and combined process in the alkaline alumina production.

3. The preparation method of the red mud-based mercury-sulfurization material as described in claim 1, characterized in that, The amount of fine selenium powder seed crystals used is 1% to 20% of the weight of the selenium source.

4. The preparation method of the red mud-based mercury-sulfurization material as described in claim 1, characterized in that, The aging and modification time is more than 0.5 hours.

5. The preparation method of the red mud-based mercury-sulfurization material as described in claim 1, characterized in that, It also includes the step of granulating the red mud-based mercury-sulfurization material to obtain granular red mud-based mercury-sulfurization material.

6. A red mud-based mercury-desulfurizing material prepared by the preparation method according to any one of claims 1 to 5.

7. The application of a red mud-based mercury-removing sulfur material prepared by the preparation method according to any one of claims 1 to 5 in the simultaneous removal of sulfur dioxide and mercury from flue gas.

8. The application of the red mud-based mercury-removing sulfur material prepared by the method described in claim 7 in the simultaneous removal of sulfur dioxide and mercury from flue gas, characterized in that, The removal method is either dry adsorption or wet adsorption.

9. The application of the red mud-based mercury-removing sulfur material prepared by the method described in claim 7 in the simultaneous removal of sulfur dioxide and mercury from flue gas, characterized in that, The temperature during the removal stage is 20~200℃.

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