A method for removing mercury from non-ferrous metal smelting flue gas using acid production

Abstract

This invention relates to the field of smelting flue gas treatment technology, specifically a method for removing mercury from non-ferrous metal smelting flue gas. The flue gas generated from non-ferrous metal smelting is washed and demisted before reacting with an adsorbent to remove mercury, and then undergoes a two-stage conversion and two-stage adsorption process. The adsorbent is polyionic liquid-coated lanthanum manganate fiber. The method for removing mercury from non-ferrous metal smelting flue gas provided by this invention can effectively adsorb and remove mercury to produce acid, which can reduce environmental pollution and has certain economic value.

Description

Technical Field

[0001] This invention relates to the field of smelting flue gas treatment technology, specifically a method for removing mercury from non-ferrous metal smelting flue gas by acid production. Background Technology

[0002] Non-ferrous metal smelting flue gas contains a large amount of sulfur dioxide. Direct emission of sulfur dioxide not only wastes resources but also poses a significant threat to the environment. Organizing the collection of sulfur dioxide-containing flue gas from the smelting system and centrally processing it into an acid production system to produce industrial sulfuric acid can both recover resources and reduce environmental pressure.

[0003] In non-ferrous metal smelting, due to mercury's low boiling point and high volatility, the mercury sulfide produced by the high-temperature reaction can be directly oxidized at high temperatures in the furnace to generate mercury vapor and sulfur dioxide gas without reduction, which then enters the smelting flue gas. In the purification section of the acid production system, mercury vapor is highly volatile, dispersing into the equipment and the environment, seriously affecting human health, polluting the environment, and leading to abnormally high mercury content in the produced sulfuric acid. Summary of the Invention

[0004] Purpose of the invention: In view of the above-mentioned technical problems, the present invention proposes a method for removing mercury from non-ferrous metal smelting flue gas by acid production.

[0005] The technical solution adopted is as follows:

[0006] A method for removing mercury from non-ferrous metal smelting flue gas by acid production:

[0007] The flue gas generated from non-ferrous metal smelting is washed and demisted, then reacts with an adsorbent to remove mercury, and then goes through a two-conversion and two-absorption process.

[0008] The adsorbent is lanthanum manganate fiber coated with polyionic liquid.

[0009] Furthermore, the polyionic liquid is formed by free radical polymerization of a vinylimidazolium-type ionic liquid.

[0010] Furthermore, the anions of the vinylimidazole-type ionic liquid are chloride ions and amino acid ions.

[0011] Furthermore, the cationic structure of the vinylimidazole-type ionic liquid is as follows:

[0012]

[0013] R1 and R2 are different; one is an alkenyl group (C2-C6) and the other is an alkyl group (C1-C6).

[0014] Furthermore, the adsorbent is prepared as follows:

[0015] Lanthanum and manganese salts are dissolved in an organic solvent, and then polyvinylpyrrolidone is added and stirred evenly to obtain a spinning solution. After aging the spinning solution, electrospinning is performed. The precursor fibers obtained by electrospinning are dried and calcined at 700-800℃ to obtain lanthanum manganate fibers. The lanthanum manganate fibers are placed in a solvent, and vinylimidazolium chloride salt, vinylimidazolium amino acid salt, and free radical initiator are added to carry out a free radical polymerization reaction. After the reaction is completed, the precipitate is filtered out and dried.

[0016] Furthermore, the mass ratio of lanthanum manganate fiber, vinylimidazolium ionic liquid chloride salt, and vinylimidazolium ionic liquid amino acid salt is 1:0.1-0.9:0.1-0.9.

[0017] Furthermore, the flue gas temperature before mercury removal is 100-200℃.

[0018] Furthermore, the volume percentage of O2 in the flue gas before mercury removal is ≥5%.

[0019] Furthermore, the volume percentage of CO2 in the flue gas before mercury removal is ≥5%.

[0020] Furthermore, the volume percentage of water vapor in the flue gas before mercury removal is ≥5%.

[0021] The beneficial effects of this invention are:

[0022] This invention provides a method for removing mercury from non-ferrous metal smelting flue gas, which can effectively adsorb and remove mercury to produce acid, reduce environmental pollution, and also has certain economic value.

[0023] After being washed and demisted, the flue gas, catalyzed by lanthanum manganate, generates superoxide radicals from O2, which can promote the growth of Hg. 0 It is oxidized to Hg on the surface of the adsorbent. 2+ Then, it combines with the ionic liquid and is fixed on the adsorbent surface. Furthermore, O2 in the flue gas can also promote the growth of Hg. 0 Homogeneous oxidation occurs, and the Hg produced by oxidation... 2+ It readily combines with chloride ions in ionic liquids, thereby improving the mercury removal efficiency of the adsorbent.

[0024] CO2 in flue gas reacts with water vapor to form HCO3. - and CO3 2- CO3 2- Hg that can be free on the surface of the adsorbent 2+ The reaction generates HgCO3, which is then fixed on the surface of the adsorbent. The introduction of amino acid salts into the ionic liquid structure can improve the adsorbent's absorption of CO2, thereby further increasing the adsorption and removal efficiency of mercury.

[0025] The adsorbent in this invention has excellent adsorption and mercury removal performance, which can greatly improve the quality of the produced sulfuric acid and avoid the volatilization of mercury vapor in the sulfuric acid production system. Attached Figure Description

[0026] Figure 1 This is a SEM image of the lanthanum manganate fibers prepared in Example 1. Detailed Implementation

[0027] Unless otherwise specified in the examples, the conditions were performed under standard conditions or as recommended by the manufacturer. Reagents or instruments whose manufacturers are not specified are all commercially available products. Techniques not mentioned in this invention refer to existing technologies. Unless otherwise specified, the following examples and comparative examples are parallel experiments, using the same processing steps and parameters.

[0028] This invention provides a method for removing mercury from non-ferrous metal smelting flue gas by acid production:

[0029] The flue gas generated from non-ferrous metal smelting is washed and demisted before reacting with an adsorbent to remove mercury, and then undergoes a two-stage conversion and two-stage adsorption process.

[0030] Specifically, the flue gas generated from non-ferrous metal smelting first enters a scrubbing tower where it is washed with 8% sulfuric acid (by mass fraction). The purpose of this is to cool the flue gas and remove fine dust particles and some gaseous impurities. Next, it passes through an electrostatic precipitator to remove mist, which removes suspended liquid particles such as sulfuric acid mist, arsenic and selenium oxides, and hydrogen fluoride. The flue gas then enters a mercury removal process where it reacts with an adsorbent to remove mercury. After mercury removal, the flue gas enters a converter where it undergoes a conversion under vanadium catalyst catalysis. The conversion principle is SO2 + 1 / 2O2 → SO3. This reaction has two characteristics: First, it is a reversible exothermic reaction. Therefore, the direction and extent of the reaction vary depending on the conditions. Second, the conversion reaction requires the catalytic action of a catalyst, and the temperature must be maintained within the catalyst's active range to achieve a certain rate. After initial conversion, the flue gas enters an absorption tower where it comes into contact with 93-98% sulfuric acid for primary absorption. SO3 dissolves in the sulfuric acid. The principle of this process is SO3 + H2O → H2SO4. While the chemical reaction equation suggests that water could be used to absorb SO3, this is impractical for industrial production. Sulfuric acid production has specific requirements for SO3 absorption; it demands rapid and complete absorption to produce concentrated sulfuric acid. 93-98% sulfuric acid is the ideal SO3 absorbent because sulfuric acid below 93% concentration does not contain SO3 vapor but does contain water vapor, while sulfuric acid above 98% does not contain water vapor but does contain SO3 vapor. The higher the concentration, the more SO3 vapor is produced. The flue gas then enters a converter for secondary conversion under vanadium catalyst catalysis. The flue gas after this secondary conversion then enters the absorption tower for a second absorption process with 93-98% sulfuric acid. This two-stage conversion and absorption process improves the conversion rate of sulfur dioxide and the absorption rate of sulfur trioxide, thereby reducing emissions, minimizing environmental pollution, and increasing sulfuric acid yield.

[0031] The adsorbent is lanthanum manganate fiber coated with polyionic liquid.

[0032] In one embodiment of the present invention, the polyionic liquid is formed by free radical polymerization of a vinylimidazolium-type ionic liquid.

[0033] In one embodiment of the present invention, the anions of the vinylimidazole ionic liquid are chloride ions and amino acid ions.

[0034] The adsorption principle of the adsorbent may be as follows: O2 generates superoxide radicals under the catalysis of lanthanum manganate, and the superoxide radicals can promote the adsorption of Hg. 0 It is oxidized to Hg on the surface of the adsorbent. 2+ Then, it combines with the ionic liquid and is fixed on the adsorbent surface. Furthermore, O2 in the flue gas can also promote the growth of Hg. 0 Homogeneous oxidation occurs, and the Hg produced by oxidation... 2+ It readily combines with chloride ions in ionic liquids, thereby improving the mercury removal efficiency of the adsorbent. Possible reactions include:

[0035] O2 + 1 / 2O2 → O3

[0036] O3 + H2O → 2HO2

[0037] Hg 0 +1 / 2O2 - →HgO

[0038] 2Cl - +Hg 2+ →HgCl2

[0039] In addition, CO2 in the flue gas reacts with water vapor to form HCO3. - and CO3 2- CO3 2- Hg that can be free on the surface of the adsorbent 2+ The reaction produces HgCO3, which is then fixed on the surface of the adsorbent. Possible reactions include:

[0040] CO2 + H2O → HCO3- - +H +

[0041] HCO3 - →CO3 2- +H +

[0042] Hg 2+ +CO3 2- →HgCO3

[0043] It is evident that CO2 has a significant impact on the adsorption and mercury removal performance of adsorbents. The introduction of amino acid salts into the ionic liquid structure of this invention can improve the adsorbent's absorption of CO2, thereby increasing the mercury removal efficiency.

[0044] In one embodiment of the present invention, the cationic structure of the vinylimidazole ionic liquid is as follows:

[0045]

[0046] R1 and R2 are different; one is an alkenyl group (C2-C6) and the other is an alkyl group (C1-C6).

[0047] In one embodiment of the present invention, R1 is vinyl, linear or branched propenyl, linear or branched butenyl, linear or branched pentenyl, linear or branched hexenyl, and R2 is methyl, ethyl, linear or branched propyl, linear or branched butyl, linear or branched pentyl, linear or branched hexyl.

[0048] In one embodiment of the present invention, R1 is methyl, ethyl, linear or branched propyl, linear or branched butyl, linear or branched pentyl, linear or branched hexyl, and R2 is vinyl, linear or branched propenyl, linear or branched butenyl, linear or branched pentenyl, linear or branched hexenyl.

[0049] In one embodiment of the present invention, R1 is vinyl and R2 is n-butyl or R1 is n-butyl and R2 is vinyl.

[0050] The adsorbent is prepared as follows:

[0051] Lanthanum and manganese salts are dissolved in an organic solvent, and then polyvinylpyrrolidone is added and stirred evenly to obtain a spinning solution. After aging the spinning solution, electrospinning is performed. The precursor fibers obtained by electrospinning are dried and calcined at 700-800℃ to obtain lanthanum manganate fibers. The lanthanum manganate fibers are placed in a solvent, and vinylimidazolium chloride salt, vinylimidazolium amino acid salt, and free radical initiator are added to carry out a free radical polymerization reaction. After the reaction is completed, the precipitate is filtered out and dried.

[0052] In one embodiment of the present invention, the mass ratio of lanthanum manganate fiber, vinylimidazole ionic liquid chloride salt and vinylimidazole ionic liquid amino acid salt is 1:0.1-0.9:0.1-0.9.

[0053] Specifically, the preferred mass ratio of lanthanum manganate fiber, vinylimidazole ionic liquid chloride salt, and vinylimidazole ionic liquid amino acid salt is 1:0.5:0.5.

[0054] Specifically, the flue gas temperature before mercury removal is 100-200℃. If the flue gas temperature is too high, it will cause the polyionic liquid to decompose. If the temperature is below 100℃, water vapor will condense. The reduction in water vapor content will lead to a decrease in the adsorption and removal effect of mercury. The preferred flue gas temperature before mercury removal is 120℃.

[0055] Specifically, the volume percentage of O2 in the flue gas before mercury removal is ≥5%.

[0056] Specifically, the volume percentage of CO2 in the flue gas before mercury removal is ≥5%.

[0057] Specifically, the volume percentage of water vapor in the flue gas before mercury removal is ≥5%.

[0058] Example 1:

[0059] In this embodiment, the adsorbent is lanthanum manganate fiber coated with a polyionic liquid, and the preparation method is as follows:

[0060] 0.01 mol of lanthanum nitrate and 0.01 mol of manganese acetate were dissolved in an organic solvent consisting of 50 ml of N,N-dimethylformamide and 50 ml of anhydrous ethanol. 1 g of polyvinylpyrrolidone was then added, and the mixture was stirred for 30 min to obtain a spinning solution. After the spinning solution was allowed to stand and age for 8 h, electrospinning was performed. The spinning solution was drawn into a syringe (equipped with a 25-gauge needle), and the power was turned on. The spinning solution was electrospun onto a regularly rotating drum-shaped collector (the distance between the needle and the drum-shaped collector was 15 cm, the high-voltage DC power supply voltage was 18 kV, the feed rate was 15 μL / min, and the ambient temperature and humidity were maintained at 30℃ and 30% RH). The collected precursor fibers were dried in an oven at 80℃ for 24 h, then transferred to a muffle furnace and calcined at 750℃ for 2 h at a rate of 2℃ / min. The furnace was then cooled to room temperature to obtain lanthanum manganate fibers. The SEM image is shown below. Figure 1 .

[0061] Anion exchange resin was regenerated by soaking in a 5% sodium hydroxide solution to load it with basic -OH ions. The soaked anion exchange resin was then washed with deionized water until the pH reached neutral. The washed anion exchange resin was then packed into an ion exchange column. 18.7 g of 1-vinyl-3-butylimidazolium chloride was weighed and dissolved in deionized water, then added to the anion exchange column for anion exchange to obtain a hydroxide ionic liquid. 15 g of L-lysine was added to the hydroxide ionic liquid solution, and the mixture was stirred continuously until completely dissolved. Stirring was continued at 30°C for 24 hours. After the reaction was complete, water was removed by vacuum distillation. The resulting product was then vacuum dried to constant weight to obtain 1-vinyl-3-butylimidazolium lysine salt.

[0062] Lanthanum manganate fibers were placed in a solvent (N,N-dimethyl sulfoxide to deionized water, volume ratio 1:1), and then 1-vinyl-3-butylimidazolium chloride, 1-vinyl-3-butylimidazolium lysine salt, and free radical initiator KPS were added. The mass ratio of lanthanum manganate fibers, 1-vinyl-3-butylimidazolium chloride, and 1-vinyl-3-butylimidazolium lysine salt was 1:0.5:0.5. The amount of solvent used was 100 times the mass of lanthanum manganate fibers, and the amount of free radical initiator KPS was 0.1% of the sum of the masses of 1-vinyl-3-butylimidazolium chloride and 1-vinyl-3-butylimidazolium lysine salt. The mixture was heated to 80°C and reacted for 24 hours. The solid was then filtered out and vacuum dried to constant weight.

[0063] Example 2:

[0064] In this embodiment, the adsorbent is lanthanum manganate fiber coated with a polyionic liquid, and the preparation method is as follows:

[0065] 0.01 mol of lanthanum nitrate and 0.01 mol of manganese acetate were dissolved in an organic solvent consisting of 50 ml of N,N-dimethylformamide and 50 ml of anhydrous ethanol. 1 g of polyvinylpyrrolidone was then added, and the mixture was stirred for 30 min to obtain a spinning solution. After the spinning solution was allowed to stand and age for 8 h, electrospinning was performed. The spinning solution was drawn into a syringe (equipped with a 25 gauge needle), the power was turned on, and the spinning solution was carefully electrospun onto a regularly rotating drum-shaped collector (the distance between the needle and the drum-shaped collector was 15 cm, the high-voltage DC power supply voltage was 18 kV, the feed rate was 15 μL / min, and the ambient temperature and humidity were maintained at 30℃ and 30% RH). The collected precursor fibers were dried in an oven at 80℃ for 24 h, and then transferred to a muffle furnace and heated to 750℃ at a rate of 2℃ / min for 2 h. After furnace cooling to room temperature, lanthanum manganate fibers were obtained.

[0066] The anion exchange resin was regenerated by soaking in an equal volume of 5% sodium hydroxide solution to load it with basic -OH ions. The soaked anion exchange resin was then washed with deionized water until the pH reached neutral. The washed resin was then packed into an ion exchange column. 18.7 g of 1-vinyl-3-butylimidazolium chloride was dissolved in deionized water and added to the anion exchange column for anion exchange, yielding a hydroxide ionic liquid. 15 g of L-lysine was added to the hydroxide ionic liquid solution, and the mixture was stirred continuously until completely dissolved. Stirring was continued at 30°C for 24 hours. After the reaction was complete, water was removed by vacuum distillation. The resulting product was then vacuum dried to constant weight to obtain 1-vinyl-3-butylimidazolium lysine salt.

[0067] Lanthanum manganate fibers were placed in a solvent (N,N-dimethyl sulfoxide to deionized water, volume ratio 1:1), and then 1-vinyl-3-butylimidazolium chloride, 1-vinyl-3-butylimidazolium lysine salt, and free radical initiator KPS were added. The mass ratio of lanthanum manganate fibers, 1-vinyl-3-butylimidazolium chloride, and 1-vinyl-3-butylimidazolium lysine salt was 1:0.9:0.1. The amount of solvent used was 100 times the mass of lanthanum manganate fibers, and the amount of free radical initiator KPS was 0.1% of the sum of the masses of 1-vinyl-3-butylimidazolium chloride and 1-vinyl-3-butylimidazolium lysine salt. The mixture was heated to 80°C and reacted for 24 hours. The solid was then filtered out and dried under vacuum to constant weight.

[0068] Example 2:

[0069] In this embodiment, the adsorbent is lanthanum manganate fiber coated with a polyionic liquid, and the preparation method is as follows:

[0070] 0.01 mol of lanthanum nitrate and 0.01 mol of manganese acetate were dissolved in an organic solvent consisting of 50 ml of N,N-dimethylformamide and 50 ml of anhydrous ethanol. 1 g of polyvinylpyrrolidone was then added, and the mixture was stirred for 30 min to obtain a spinning solution. After the spinning solution was allowed to stand and age for 8 h, electrospinning was performed. The spinning solution was drawn into a syringe (equipped with a 25 gauge needle), the power was turned on, and the spinning solution was carefully electrospun onto a regularly rotating drum-shaped collector (the distance between the needle and the drum-shaped collector was 15 cm, the high-voltage DC power supply voltage was 18 kV, the feed rate was 15 μL / min, and the ambient temperature and humidity were maintained at 30℃ and 30% RH). The collected precursor fibers were dried in an oven at 80℃ for 24 h, and then transferred to a muffle furnace and heated to 750℃ at a rate of 2℃ / min for 2 h. After furnace cooling to room temperature, lanthanum manganate fibers were obtained.

[0071] The anion exchange resin was regenerated by soaking in an equal volume of 5% sodium hydroxide solution to load it with basic -OH ions. The soaked anion exchange resin was then washed with deionized water until the pH reached neutral. The washed resin was then packed into an ion exchange column. 18.7 g of 1-vinyl-3-butylimidazolium chloride was dissolved in deionized water and added to the anion exchange column for anion exchange, yielding a hydroxide ionic liquid. 15 g of L-lysine was added to the hydroxide ionic liquid solution, and the mixture was stirred continuously until completely dissolved. Stirring was continued at 30°C for 24 hours. After the reaction was complete, water was removed by vacuum distillation. The resulting product was then vacuum dried to constant weight to obtain 1-vinyl-3-butylimidazolium lysine salt.

[0072] Lanthanum manganate fibers were placed in a solvent (N,N-dimethyl sulfoxide to deionized water, volume ratio 1:1), and then 1-vinyl-3-butylimidazolium chloride, 1-vinyl-3-butylimidazolium lysine salt, and free radical initiator KPS were added. The mass ratio of lanthanum manganate fibers, 1-vinyl-3-butylimidazolium chloride, and 1-vinyl-3-butylimidazolium lysine salt was 1:0.1:0.9. The amount of solvent used was 100 times the mass of lanthanum manganate fibers, and the amount of free radical initiator KPS was 0.1% of the sum of the masses of 1-vinyl-3-butylimidazolium chloride and 1-vinyl-3-butylimidazolium lysine salt. The mixture was heated to 80°C and reacted for 24 hours. The solid was then filtered out and dried under vacuum to constant weight.

[0073] Example 4:

[0074] In this embodiment, the adsorbent is lanthanum manganate fiber coated with a polyionic liquid, and the preparation method is as follows:

[0075] 0.01 mol of lanthanum nitrate and 0.01 mol of manganese acetate were dissolved in an organic solvent consisting of 50 ml of N,N-dimethylformamide and 50 ml of anhydrous ethanol. 1 g of polyvinylpyrrolidone was then added, and the mixture was stirred for 30 min to obtain a spinning solution. The spinning solution was allowed to stand and age for 8 h before electrospinning. The spinning solution was drawn into a syringe (equipped with a 25-gauge needle), and the power was turned on. The spinning solution was electrospun onto a regularly rotating drum-shaped collector (the distance between the needle and the drum-shaped collector was 15 cm, the high-voltage DC power supply voltage was 18 kV, the feed rate was 15 μL / min, and the ambient temperature and humidity were maintained at 30℃ and 30% RH). The collected precursor fibers were dried in an oven at 80℃ for 24 h, and then transferred to a muffle furnace and heated to 750℃ at a rate of 2℃ / min for 2 h. After furnace cooling to room temperature, lanthanum manganate fibers were obtained.

[0076] Anion exchange resin was regenerated by soaking in a 5% sodium hydroxide solution to load it with basic -OH ions. The soaked anion exchange resin was then washed with deionized water until the pH reached neutral. The washed anion exchange resin was then packed into an ion exchange column. 18.7 g of 1-vinyl-3-butylimidazolium chloride was weighed and dissolved in deionized water, then added to the anion exchange column for anion exchange to obtain a hydroxide ionic liquid. 17 g of arginine was added to the hydroxide ionic liquid solution, and the mixture was stirred continuously until completely dissolved. Stirring was continued at 30°C for 24 hours. After the reaction was complete, water was removed by vacuum distillation. The resulting product was then vacuum dried to constant weight to obtain 1-vinyl-3-butylimidazolium arginine salt.

[0077] Lanthanum manganate fibers were placed in a solvent (N,N-dimethyl sulfoxide to deionized water, volume ratio 1:1), and then 1-vinyl-3-butylimidazolium chloride, 1-vinyl-3-butylimidazolium arginine salt, and free radical initiator KPS were added. The mass ratio of lanthanum manganate fibers, 1-vinyl-3-butylimidazolium chloride, and 1-vinyl-3-butylimidazolium arginine salt was 1:0.5:0.5. The amount of solvent used was 100 times the mass of lanthanum manganate fibers, and the amount of free radical initiator KPS was 0.1% of the sum of the masses of 1-vinyl-3-butylimidazolium chloride and 1-vinyl-3-butylimidazolium arginine salt. The mixture was heated to 80°C and reacted for 24 hours. The solid was then filtered out and dried under vacuum to constant weight.

[0078] Comparative Example 1:

[0079] It is basically the same as Example 1, except that the adsorbent is lanthanum manganate fiber.

[0080] The preparation method of the adsorbent is as follows:

[0081] 0.01 mol of lanthanum nitrate and 0.01 mol of manganese acetate were dissolved in an organic solvent consisting of 50 ml of N,N-dimethylformamide and 50 ml of anhydrous ethanol. 1 g of polyvinylpyrrolidone was then added, and the mixture was stirred for 30 min to obtain a spinning solution. The spinning solution was allowed to stand and age for 8 h before electrospinning. The spinning solution was drawn into a syringe (equipped with a 25-gauge needle), and the power was turned on. The spinning solution was electrospun onto a regularly rotating drum-shaped collector (the distance between the needle and the drum-shaped collector was 15 cm, the high-voltage DC power supply voltage was 18 kV, the feed rate was 15 μL / min, and the ambient temperature and humidity were maintained at 30℃ and 30% RH). The collected precursor fibers were dried in an oven at 80℃ for 24 h, and then transferred to a muffle furnace and heated to 750℃ at a rate of 2℃ / min for 2 h. After furnace cooling to room temperature, lanthanum manganate fibers were obtained.

[0082] Comparative Example 2:

[0083] The process is basically the same as in Example 1, except that the adsorbent is a polyionic liquid coated with lanthanum manganate fiber, wherein the polyionic liquid is obtained by free radical polymerization of 1-vinyl-3-butylimidazolium chloride.

[0084] The preparation method of the adsorbent is as follows:

[0085] 0.01 mol of lanthanum nitrate and 0.01 mol of manganese acetate were dissolved in an organic solvent consisting of 50 ml of N,N-dimethylformamide and 50 ml of anhydrous ethanol. 1 g of polyvinylpyrrolidone was then added, and the mixture was stirred for 30 min to obtain a spinning solution. The spinning solution was allowed to stand and age for 8 h before electrospinning. The spinning solution was drawn into a syringe (equipped with a 25-gauge needle), and the power was turned on. The spinning solution was electrospun onto a regularly rotating drum-shaped collector (the distance between the needle and the drum-shaped collector was 15 cm, the high-voltage DC power supply voltage was 18 kV, the feed rate was 15 μL / min, and the ambient temperature and humidity were maintained at 30℃ and 30% RH). The collected precursor fibers were dried in an oven at 80℃ for 24 h, and then transferred to a muffle furnace and heated to 750℃ at a rate of 2℃ / min for 2 h. After furnace cooling to room temperature, lanthanum manganate fibers were obtained.

[0086] Lanthanum manganate fiber was placed in a solvent (N,N-dimethyl sulfoxide to deionized water volume ratio 1:1), and then 1-vinyl-3-butylimidazolium chloride and free radical initiator KPS were added. The mass ratio of lanthanum manganate fiber to 1-vinyl-3-butylimidazolium chloride was 1:1, the amount of solvent was 100 times the mass of lanthanum manganate fiber, and the amount of free radical initiator KPS was 0.1% of the mass of 1-vinyl-3-butylimidazolium chloride. The mixture was heated to 80°C and reacted for 24 hours. The solid was then filtered out and vacuum dried to constant weight.

[0087] Comparative Example 3:

[0088] It is basically the same as Example 1, except that the adsorbent is lanthanum manganate fiber coated with polyionic liquid.

[0089] The polyionic liquid was obtained by free radical polymerization of 1-vinyl-3-butylimidazolium lysine salt.

[0090] The preparation method of the adsorbent is as follows:

[0091] 0.01 mol of lanthanum nitrate and 0.01 mol of manganese acetate were dissolved in an organic solvent consisting of 50 ml of N,N-dimethylformamide and 50 ml of anhydrous ethanol. 1 g of polyvinylpyrrolidone was then added, and the mixture was stirred for 30 min to obtain a spinning solution. The spinning solution was allowed to stand and age for 8 h before electrospinning. The spinning solution was drawn into a syringe (equipped with a 25-gauge needle), and the power was turned on. The spinning solution was electrospun onto a regularly rotating drum-shaped collector (the distance between the needle and the drum-shaped collector was 15 cm, the high-voltage DC power supply voltage was 18 kV, the feed rate was 15 μL / min, and the ambient temperature and humidity were maintained at 30℃ and 30% RH). The collected precursor fibers were dried in an oven at 80℃ for 24 h, and then transferred to a muffle furnace and heated to 750℃ at a rate of 2℃ / min for 2 h. After furnace cooling to room temperature, lanthanum manganate fibers were obtained.

[0092] Anion exchange resin was regenerated by soaking in a 5% sodium hydroxide solution to load it with basic -OH ions. The soaked anion exchange resin was then washed with deionized water until the pH reached neutral. The washed anion exchange resin was then packed into an ion exchange column. 18.7 g of 1-vinyl-3-butylimidazolium chloride was weighed and dissolved in deionized water, then added to the anion exchange column for anion exchange to obtain a hydroxide ionic liquid. 15 g of L-lysine was added to the hydroxide ionic liquid solution, and the mixture was stirred continuously until completely dissolved. Stirring was continued at 30°C for 24 hours. After the reaction was complete, water was removed by vacuum distillation. The resulting product was then vacuum dried to constant weight to obtain 1-vinyl-3-butylimidazolium lysine salt.

[0093] Lanthanum manganate fiber was placed in a solvent (N,N-dimethyl sulfoxide to deionized water volume ratio 1:1), and then 1-vinyl-3-butylimidazolium lysine salt and free radical initiator KPS were added. The mass ratio of lanthanum manganate fiber to 1-vinyl-3-butylimidazolium lysine salt was 1:1, the amount of solvent was 100 times the mass of lanthanum manganate fiber, and the amount of free radical initiator KPS was 0.1% of the mass of 1-vinyl-3-butylimidazolium lysine salt. The mixture was heated to 80°C and reacted for 24 hours. The solid was then filtered out and vacuum dried to constant weight.

[0094] Comparative Example 4:

[0095] The experiment is basically the same as in Example 1, except that lanthanum manganate fibers are replaced with commercially available lanthanum manganate powder (Jinshilan (Xiamen) New Materials Co., Ltd.).

[0096] Comparative Example 5:

[0097] The method is basically the same as in Example 1, except that lanthanum manganate fibers are replaced with commercially available manganese dioxide powder (Jinan Changyingda Chemical Co., Ltd.).

[0098] Performance testing:

[0099] The adsorbents prepared by the methods in Examples 1-4 and Comparative Examples 1-5 of this invention were selected as samples for mercury removal performance evaluation tests. First, the mercury analyzer was turned on and zeroed. 2g of sample was weighed and placed in a quartz tube as the adsorption unit. After the mercury analyzer was zeroed, it was connected to the gas passage. The gas cylinder was turned on, and the gas flow meter was adjusted so that the total flow rate of N2, SO2, O2, CO2, and H2O was 1.9 L / min, and the mercury-loaded N2 flow rate was 0.1 L / min. The constant-temperature water bath of the mercury generator was turned on, and the water bath temperature was adjusted to stabilize the initial mercury concentration in the simulated flue gas at 50 μg / m³. 3 The simulated flue gas temperature was set at 120℃, and the volume percentages of N2, SO2, O2, CO2, and H2O were 55%, 30%, 5%, 5%, and 5%, respectively. The simulated flue gas entered the desulfurization liquid after passing through the adsorption unit, and the mercury removal test time was 60 minutes. The average mercury removal efficiency of different samples was compared.

[0100] Average mercury removal efficiency The calculation formula is as follows:

[0101] ;

[0102] In the formula: C0 is Hg 0 The initial concentration, Ct, represents the Hg concentration in the flue gas at different times after the flue gas passes through the adsorption unit. 0 concentration.

[0103] The test results are shown in Table 1 below:

[0104]

[0105] As shown in Table 1 above, the adsorbent in this invention has excellent adsorption and mercury removal performance.

[0106] The comparison of Examples 1-3 shows that the adsorbent exhibits the best mercury adsorption and removal performance when the mass ratio of 1-vinyl-3-butylimidazolium chloride to 1-vinyl-3-butylimidazolium lysine salt is 0.5:0.5.

[0107] The comparison between Examples 1 and 4 shows that, compared with 1-vinyl-3-butylimidazolium lysine salt, 1-vinyl-3-butylimidazolium arginine salt can better improve the adsorption and mercury removal performance of the adsorbent.

[0108] The comparison between Example 1 and Comparative Example 1 shows that polyionic liquid coating can effectively improve the adsorption and mercury removal performance of the adsorbent.

[0109] The comparison between Example 1 and Comparative Example 2 shows that the introduction of 1-vinyl-3-butylimidazolium lysine salt plays a positive role in improving the adsorption and removal performance of the adsorbent.

[0110] The comparison between Example 1 and Comparative Example 3 shows that the introduction of 1-vinyl-3-butylimidazolium chloride plays a positive role in improving the adsorption and removal performance of the adsorbent.

[0111] The comparison between Example 1 and Comparative Example 4 shows that the adsorption and mercury removal effect of lanthanum manganate fiber is better than that of commercially available lanthanum manganate powder.

[0112] The comparison between Example 1 and Comparative Example 5 shows that the adsorption and mercury removal effect of lanthanum manganate fiber is better than that of commercially available manganese dioxide powder.

[0113] The above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit it. 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. Such 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 removing mercury from non-ferrous metal smelting flue gas by acid production, characterized in that, The flue gas generated from non-ferrous metal smelting is washed and demisted, then reacts with an adsorbent to remove mercury, and then goes through a two-conversion and two-absorption process. The adsorbent is lanthanum manganate fiber coated with polyionic liquid; The polyionic liquid is formed by free radical polymerization of vinylimidazolium-type ionic liquid; The anions of the vinylimidazolium-type ionic liquid are chloride ions and amino acid ions.

2. The method for removing mercury from non-ferrous metal smelting flue gas using acid production as described in claim 1, characterized in that, The cationic structure of the vinylimidazolium-type ionic liquid is as follows: ； R1 and R2 are different; one is an alkenyl group (C2-C6) and the other is an alkyl group (C1-C6).

3. The method for removing mercury from non-ferrous metal smelting flue gas using acid production as described in claim 1, characterized in that, The adsorbent is prepared as follows: Lanthanum and manganese salts are dissolved in an organic solvent, and then polyvinylpyrrolidone is added and stirred evenly to obtain a spinning solution. After aging the spinning solution, electrospinning is performed. The precursor fibers obtained by electrospinning are dried and calcined at 700-800℃ to obtain lanthanum manganate fibers. The lanthanum manganate fibers are placed in a solvent, and vinylimidazolium chloride salt, vinylimidazolium amino acid salt, and free radical initiator are added to carry out a free radical polymerization reaction. After the reaction is completed, the solution is filtered out and dried.

4. The method for removing mercury from non-ferrous metal smelting flue gas using acid production as described in claim 3, characterized in that, The mass ratio of lanthanum manganate fiber, vinylimidazolium ionic liquid chloride salt, and vinylimidazolium ionic liquid amino acid salt is 1:0.1-0.9:0.1-0.

9.

5. The method for removing mercury from non-ferrous metal smelting flue gas using acid production as described in claim 1, characterized in that, The flue gas temperature before mercury removal is 100-200℃.

6. The method for removing mercury from non-ferrous metal smelting flue gas using acid production as described in claim 1, characterized in that, The volume percentage of O2 in the flue gas before mercury removal is ≥5%.

7. The method for removing mercury from non-ferrous metal smelting flue gas using acid production as described in claim 1, characterized in that, The volume percentage of CO2 in the flue gas before mercury removal is ≥5%.

8. The method for removing mercury from non-ferrous metal smelting flue gas using acid production as described in claim 1, characterized in that, The volume percentage of water vapor in the flue gas before mercury removal is ≥5%.

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