Preparation method of adsorbent for dechlorination and desulfurization of blast furnace gas

Abstract

The invention discloses a preparation method of an adsorbent for dechlorination and desulfurization of blast furnace gas, which comprises the following steps: adding sodium metaaluminate into an alkaline solution to obtain an aluminum solution, adding silica sol into the alkaline solution to obtain a silicon solution, mixing the aluminum solution with the silica sol, and aging; crystallizing after aging, drying, calcining, and grinding to obtain molecular sieve powder; the molecular sieve powder is sequentially placed in a dopamine solution and a metal salt solution containing phosphoric acid to be impregnated twice, calcination is conducted after impregnation is completed, and the modified molecular sieve adsorbent is obtained. The modified molecular sieve type adsorbent prepared by the method has high carbonyl sulfide and hydrogen chloride adsorption performance.

Description

Technical Field

[0001] The invention relates to the technical field of blast furnace gas dechlorination and desulfurization purification technology, and in particular to a method for preparing an adsorbent for blast furnace gas dechlorination and desulfurization. Background Art

[0002] The ironmaking process produces a large amount of blast furnace gas. The rational and effective utilization of this gas is crucial for a circular economy and energy conservation and emission reduction. In recent years, the widespread application of dry blast furnace gas dust removal and residual pressure turbine (TRT) power generation has enabled the full recovery of the pressure and heat energy of blast furnace gas, improving enterprise profitability and promoting business development. However, if harmful substances in the gas (including chlorides and sulfides) are not effectively treated, they can not only corrode pipelines and power generation equipment but also cause subsequent emissions of SO2 and HCl, resulting in serious environmental pollution.

[0003] The sulfides in blast furnace gas mainly include organic sulfur and inorganic sulfur. The concentration of COS and CS2 in organic sulfur accounts for 70% of the total sulfides, which is relatively high. Therefore, the research on the removal of carbonyl sulfide is relatively hot. For example, patent CN202210969984.9 discloses an adsorbent for deep removal of hydrogen sulfide and carbonyl sulfide in blast furnace gas, its preparation method and application, the adsorbent is composed of Fe(NO3)2·9H2O, Zn(NO3)2·6H2O and porous aluminum titanate A 12TiO5, the mass ratio of the three is 1-2:1-2:2. The adsorbent compounds the easily inactivated Fe-Zn binary desulfurizer with porous aluminum titanate A12TiO5, avoiding the carbonization and inactivation of Fe and the volatilization loss of Fe by being reduced to Zn element. The porous structure of aluminum titanate solves the high dispersion load of Fe and Zn. The prepared adsorbent has extremely high mechanical strength, thermal stability and wear resistance, which increases the service life of the desulfurizer. However, in actual use, the adsorption performance needs to be improved.

[0004] As the main by-product generated in the blast furnace ironmaking process, the composition of blast furnace gas is significantly affected by the transformation process of chlorine elements in the raw materials charged into the furnace. In a high-temperature reducing environment, the chlorine elements in the raw materials undergo a multi-stage chemical reaction chain and are ultimately enriched in the blast furnace gas in the form of hydrogen chloride (HCl). Patent CN202211018638.9 discloses a modified calcium-based adsorbent, its preparation method and application. The calcium-based adsorbent includes a calcium-based raw material and a strong base, and the mass ratio of the calcium-based raw material to the strong base is 100:(1-10). Moreover, the modified calcium-based adsorbent is prepared by a mechanical grinding method, and the mechanical grinding method includes a ball milling method. The modified calcium-based adsorbent disclosed in this patent is prepared by a method combining physical mechanical grinding and chemical strong base modification, which optimizes the calcium-based adsorbent from both physical macroscopic and chemical microscopic perspectives. The obtained modified calcium-based adsorbent has a more developed pore structure macroscopically, and its specific surface area has been significantly increased. Microscopically, the surface of the modified calcium-based adsorbent particles has more abundant basic sites, and the dechlorination efficiency has been greatly improved compared with traditional calcium-based adsorbents.

[0005] Due to the complex composition of blast furnace gas, it is particularly important to develop an adsorbent that can simultaneously remove organic sulfur and chlorides, which can not only reduce the equipment cost of the steel industry but also reduce the impact on the environment. Summary of the Invention

[0006] Aiming at the problems that the efficiency of existing adsorbents for adsorbing organic sulfur needs to be improved and existing adsorbents cannot simultaneously meet the requirements of removing organic sulfur and chlorides, the present invention provides a preparation method for an adsorbent for dechlorination and desulfurization of blast furnace gas.

[0007] To solve the above technical problems, the present invention provides the following technical solutions: A preparation method for an adsorbent for dechlorination and desulfurization of blast furnace gas, Sodium aluminate is added to an alkaline solution to obtain an aluminum solution, and silica sol is added to an alkaline solution to obtain a silicon solution. The aluminum solution and the silica sol are mixed and then aged. After aging, crystallization, drying and then calcination are carried out, and then grinding is performed to obtain a molecular sieve powder. The molecular sieve powder is successively immersed in a dopamine solution and a metal salt solution containing phosphoric acid for two times, and after the immersion is completed, calcination is carried out to obtain a modified molecular sieve adsorbent.

[0008] Further, the alkaline solution is prepared by dissolving sodium hydroxide in deionized water, and the mass ratio of sodium hydroxide, sodium aluminate, silica sol and deionized water is 4:0.08-0.12:4-8:65.

[0009] Further, the aging temperature is 60°C, and the aging time is 80-100h; The pressure during the crystallization process is 1.5 MPa, the temperature is 80 °C, and the crystallization time is 24 - 48 hours; Ethyl acetoacetate is added during both the aging and crystallization processes. The amount of ethyl acetoacetate added during aging is 2 - 5% of the volume of the silica sol, and the volume of ethyl acetoacetate added during the crystallization process is the same as that added during aging.

[0010] Furthermore, the dopamine solution is prepared by dissolving dopamine powder in 10 mM Tris - HCl buffer solution with a pH of 8 - 9, and the mass concentration of the dopamine solution is 2 - 5 g / L; Polypropylene grafted maleic anhydride is also added to the dopamine solution.

[0011] Furthermore, the concentration of polypropylene grafted maleic anhydride in the dopamine solution is 0.2 - 0.5 g / L.

[0012] Furthermore, the impregnation process of the dopamine solution is carried out at room temperature for 72 hours. After impregnation, it is washed with deionized water and then dried to obtain the polydopamine - modified molecular sieve.

[0013] Furthermore, zinc chloride, zirconium nitrate, and tin tetrachloride are dissolved in water to prepare a metal salt solution, and phosphoric acid is added to the metal salt solution to prepare a metal salt solution containing phosphoric acid. The concentration of phosphoric acid in the metal salt solution is 1 - 5 g / L.

[0014] Furthermore, the atomic ratio of zinc, zirconium, and tin in zinc chloride, zirconium nitrate, and tin tetrachloride is (1.3 - 2.4):1:(0.1 - 0.5).

[0015] Furthermore, the impregnation process of the metal salt solution containing phosphoric acid is as follows: The polydopamine - modified molecular sieve is placed in the metal salt solution containing phosphoric acid for equal - volume impregnation for 15 - 24 hours. After impregnation, it is dried and then calcined at 400 °C for 4 h. After calcination, it is taken out and placed in the metal salt solution containing phosphoric acid again for equal - volume impregnation for 20 - 48 hours. After impregnation, it is dried at 90 °C for 5 hours and then calcined at 400 °C for 5 h in an air atmosphere.

[0016] A modified molecular sieve adsorbent for dechlorination and desulfurization of blast furnace gas prepared by the preparation method according to any one of the above.

[0017] The present invention has the following beneficial effects: 1. A preparation method of an adsorbent for dechlorination and desulfurization of blast furnace gas provided by the present invention. During the preparation of the adsorbent, through the dual modification treatment of polydopamine and metal salts on the molecular sieve, the adsorbent has high adsorption performance for carbonyl sulfide and hydrogen chloride. At an adsorption temperature of 50°C - 100°C, it can show excellent adsorption effect in 0.5 hours, without the need to use two adsorbents separately to adsorb carbonyl sulfide and hydrogen chloride as in the prior art, which can effectively reduce production costs and improve economic benefits.

[0018] 2. A preparation method of an adsorbent for dechlorination and desulfurization of blast furnace gas provided by the present invention. By properly proportioning zinc chloride, zirconium nitrate, and tin tetrachloride, the addition of tin tetrachloride makes the prepared adsorbent show good adsorption effect for hydrogen chloride. At the same time, adding a certain amount of phosphoric acid to the metal salt solution can obtain good adsorption effect for carbonyl sulfide.

[0019] 3. A preparation method of an adsorbent for dechlorination and desulfurization of blast furnace gas provided by the present invention. During the preparation of the adsorbent, ethyl acetoacetate is added in both the aging and crystallization processes, making the adsorbent have a high specific surface area and pore size, thereby increasing the loading amount of the metal salt component and improving the adsorption effect.

[0020] 4. A preparation method of an adsorbent for dechlorination and desulfurization of blast furnace gas provided by the present invention. The preparation method of the adsorbent is easy to control and the preparation method is simple. Specific Embodiments

[0021] Next, the technical solutions of the present invention will be clearly and completely described in conjunction with specific embodiments. The reagents and equipment used in the present invention are all known products or obtained by purchasing commercially available products. Among them, silica sol is purchased from Zhejiang Yuda Chemical Co., Ltd., and the specific model of the silica sol is ZS-30 (the content of silicon dioxide is 30%).

[0022] Example 1 Weigh each component according to the mass ratio of sodium hydroxide, sodium aluminate, silica sol, and deionized water as 4:0.08:8:65. Dissolve the weighed sodium hydroxide in deionized water and stir until dissolved to prepare an alkali solution. Then slowly add the weighed sodium aluminate to the alkali solution and stir until the solution becomes transparent to prepare an aluminum solution. The preparation of the above alkali solution and the addition of sodium aluminate to the alkali solution are both carried out in a polypropylene bottle.

[0023] Place a certain amount of weighed silica sol in a polypropylene bottle, add ethyl acetoacetate with a volume of 2% of the silica sol to the bottle, and then drop the aluminum solution into the silica sol. Let it stand for 100 h under the water bath condition of 60°C for aging.

[0024] After the aging is completed, the components in the above-mentioned polypropylene bottles are added to a high-pressure reactor with a polytetrafluoroethylene lining. At the same time, ethyl acetoacetate with the same volume as that during aging is continuously added to this system, and it is placed in an oven. The oven is set at 80 °C, and crystallization is carried out under this condition for 40 h to obtain the product.

[0025] After the crystallization is completed, the product is cooled to room temperature, and the product is repeatedly washed with deionized water until it is neutral. The dried product is calcined in a muffle furnace at 600 °C with a heating rate of 2 °C·min -1 for 7 h, and then ground to obtain the molecular sieve powder.

[0026] Dissolve the hydrochloric acid dopamine powder in Tris solution (pH 8.5, 10 mM, Tris-HCl buffer solution) to prepare a dopamine solution. The concentration of dopamine is 10 g / L. At the same time, the dopamine solution contains polypropylene grafted maleic anhydride with a mass concentration of 1 g / L. Ultrasonically disperse the molecular sieve powder in the above dopamine solution, and immerse it for 72 hours at room temperature without stirring. After the immersion is completed, wash it with deionized water, and dry it to remove moisture to obtain the polydopamine-modified molecular sieve.

[0027] Weigh the corresponding compounds according to the atomic ratio of zinc, zirconium, and tin in zinc chloride, zirconium nitrate pentahydrate, and tin tetrachloride pentahydrate being 2:1:0.5. Dissolve the above three compounds in deionized water to prepare a metal salt solution. Add phosphoric acid to the metal salt solution to prepare a metal salt solution containing phosphoric acid. The concentration of phosphoric acid in the metal salt solution is 1 g / L. Divide the metal salt solution containing phosphoric acid into two parts for the subsequent two immersions.

[0028] Place the polydopamine-modified molecular sieve in one part of the metal salt solution containing phosphoric acid for equal-volume immersion. The immersion time is 24 hours. After the immersion is completed, dry it at 90 °C for 24 hours, and then the programmed heating rate is 2 °C·min -1 Heat up to 400 °C and continue to maintain this temperature in an air atmosphere for roasting for 4 h. After roasting, take it out and place it in the other part of the metal salt solution containing phosphoric acid for equal-volume immersion again. The immersion time is 48 hours. After the immersion is completed, dry it, and then the programmed heating rate in an air atmosphere is 5 °C·min -1 Heat up to 400 °C and continue to maintain this temperature for roasting for 5 h..

[0029] After roasting, grind it to obtain the modified molecular sieve powder, and then carry out tabletting and screening to 30 - 40 mesh to make the finished modified molecular sieve adsorbent.

[0030] Example 2 Weigh each component according to the mass ratio of sodium hydroxide, sodium aluminate, silica sol and deionized water of 4:0.08:4:65. Dissolve the weighed sodium hydroxide in deionized water and stir until dissolved to prepare an alkali solution. Then slowly add the weighed sodium aluminate to the alkali solution and stir until the solution becomes transparent to prepare an aluminum solution. The preparation of the above alkali solution and the addition of sodium aluminate to the alkali solution are both carried out in a polypropylene bottle.

[0031] Place a certain amount of the weighed silica sol in a polypropylene bottle, add ethyl acetoacetate with a volume of 5% of the silica sol to the bottle, and then drop the aluminum solution into the silica sol. Leave it to age for 100 h under the condition of a water bath at 60 °C.

[0032] After aging, add the components in the above polypropylene bottle to a high-pressure reactor lined with polytetrafluoroethylene. At the same time, continue to add ethyl acetoacetate with the same volume as that during aging to the system, and place it in an oven. The oven is set at 80 °C, and crystallize for 40 h under this condition to obtain the product.

[0033] After crystallization, cool the product to room temperature, and repeatedly wash the product with deionized water until it is neutral. The dried product is calcined in a muffle furnace at 600 °C with a heating rate of 2 °C·min -1 for 7 h, and then grind it to obtain molecular sieve powder.

[0034] Dissolve hydrochloric acid dopamine powder in Tris solution (pH 8.5, 10 mM, Tris-HCl buffer solution) to prepare a dopamine solution. The concentration of dopamine is 30 g / L, and at the same time, the dopamine solution contains polypropylene grafted maleic anhydride with a mass concentration of 1 g / L. Ultrasonically disperse the molecular sieve powder in the above dopamine solution and soak it for 72 hours at room temperature without stirring. After soaking, wash it with deionized water, and dry it to remove moisture to obtain polydopamine-modified molecular sieve.

[0035] Weigh the corresponding compounds according to the atomic ratio of zinc, zirconium and tin in zinc chloride, zirconium nitrate pentahydrate and tin tetrachloride pentahydrate of 1.3:1:0.1, and dissolve the above three compounds in deionized water to prepare a metal salt solution. Add phosphoric acid to the metal salt solution to prepare a metal salt solution containing phosphoric acid. The concentration of phosphoric acid in the metal salt solution is 1 g / L. Divide the metal salt solution containing phosphoric acid into two parts for the following two impregnations.

[0036] Place the polydopamine-modified molecular sieve in one part of the metal salt solution containing phosphoric acid for equal-volume impregnation. The impregnation time is 15 hours. After impregnation, dry it at 90 °C for 24 hours, and then the programmed heating rate is 2 °C·min -1, heat it to 400 °C and continue to bake it at this temperature for 4 h in an air atmosphere. After baking, take it out and place it in another metal salt solution containing phosphoric acid for isovolumetric impregnation again. The impregnation time is 48 h. After impregnation, dry it, and then the programmed heating rate in an air atmosphere is 5 °C·min -1 , heat it to 400 °C and continue to bake it at this temperature for 5 h.

[0037] After baking, grind it to obtain the modified molecular sieve powder, and then press and screen it to 30-40 mesh to prepare the finished modified molecular sieve adsorbent.

[0038] Example 3 Weigh each component according to the mass ratio of sodium hydroxide, sodium aluminate, silica sol and deionized water of 4:0.12:8:65. Dissolve the weighed sodium hydroxide in deionized water and stir until it is dissolved to prepare an alkali solution. Then slowly add the weighed sodium aluminate to the alkali solution and stir until the solution becomes transparent to prepare an aluminum solution. The preparation of the above alkali solution and the addition of sodium aluminate to the alkali solution are both carried out in a polypropylene bottle.

[0039] Place a certain amount of the weighed silica sol in a polypropylene bottle, add ethyl acetoacetate with a volume of 2% of the silica sol to this bottle, and then drop the aluminum solution into the silica sol. Let it stand for 80 h at 60 °C in a water bath for aging.

[0040] After aging, add the components in the above polypropylene bottle to a high-pressure reactor lined with polytetrafluoroethylene. At the same time, continue to add ethyl acetoacetate with the same volume as that during aging to this system, and place it in an oven. The oven is set at 80 °C, and crystallize for 48 h under this condition to obtain the product.

[0041] After crystallization, cool the product to room temperature, and repeatedly wash the product with deionized water until it is neutral. The dried product is calcined in a muffle furnace at 600 °C with a heating rate of 2 °C·min -1 for 7 h, and then grind it to obtain the molecular sieve powder.

[0042] Dissolve the hydrochloric acid dopamine powder in Tris solution (pH 8.5, 10 mM, Tris-HCl buffer solution) to prepare a dopamine solution. The concentration of dopamine is 50 g / L, and at the same time, the dopamine solution contains polypropylene grafted maleic anhydride with a mass concentration of 3 g / L. Ultrasonically disperse the molecular sieve powder in the above dopamine solution, and impregnate it at room temperature for 72 h without stirring. After impregnation, wash it with deionized water, and dry it to remove moisture to obtain the polydopamine modified molecular sieve.

[0043] Weigh the corresponding compounds according to the atomic ratio of zinc, zirconium, and tin in zinc chloride, zirconium nitrate pentahydrate, and tin tetrachloride pentahydrate being 2.4:1:0.1. Dissolve the above three compounds in deionized water to prepare a metal salt solution. Add phosphoric acid to the metal salt solution to prepare a metal salt solution containing phosphoric acid, and the concentration of phosphoric acid in the metal salt solution is 5 g / L. Divide the metal salt solution containing phosphoric acid into two parts for the subsequent two impregnations.

[0044] Place the polydopamine-modified molecular sieve in one part of the metal salt solution containing phosphoric acid for isovolumetric impregnation. The impregnation time is 24 hours. After the impregnation is completed, dry at 90 °C for 24 hours, and then the programmed heating rate is 2 °C·min -1 , heat up to 400 °C and keep this temperature for roasting in an air atmosphere for 4 h. After roasting, take it out and place it in the other part of the metal salt solution containing phosphoric acid for isovolumetric impregnation again. The impregnation time is 20 hours. After the impregnation is completed, dry it, and then the programmed heating rate is 5 °C·min-1 in an air atmosphere, heat up to 400 °C and keep this temperature for roasting for 5 h.

[0045] After roasting, grind it to obtain the modified molecular sieve powder, and then press and screen it to 30 - 40 mesh to make the finished modified molecular sieve adsorbent.

[0046] Example 4 Only add ethyl acetoacetate during the crystallization process, and do not add ethyl acetoacetate during the aging process. Other experimental operations are the same as in Example 1.

[0047] Example 5 The concentration of polypropylene grafted maleic anhydride added to the dopamine solution is 0.5 g / L. Other experimental operations are the same as in Example 1.

[0048] Example 6 Exchange the order of the modified treatment of polydopamine and the treatment of the metal salt solution. Other experimental operations are the same as in Example 1.

[0049] Example 7 The concentration of phosphoric acid in the metal salt solution is 8 g / L. Other experimental operations are the same as in Example 1.

[0050] Example 8 The metal salt solution does not contain tin tetrachloride pentahydrate. Other experimental operations are the same as in Example 1.

[0051] Determination of adsorbent characterization The structure of the adsorbent of vegetation was characterized by a surface area and porosity analyzer. Before measurement, the sample was vacuum-treated and then subjected to an adsorption experiment of high-purity nitrogen at low temperature. By analyzing the N2 adsorption-desorption isotherm, in the range of 0.05 < p / p0 < 0.2, the specific surface area was calculated using the Brunauer-Emmett-Teller (BET) equation, and the total pore volume was estimated by the single-point method.

[0052] Determination of desulfurization and dechlorination effects of adsorbent In a fixed-bed micro-reactor, 1.0 g of the adsorbent was placed in the reaction tube. Quartz sand with a mesh size of 30 was filled in the upper and lower parts of the adsorbent in the reaction tube. The adsorption temperature was 30 °C, the COS gas was set at 500 ppm, the HCl concentration was set at 100 ppm, and the remaining component nitrogen was supplemented. The gas hourly space velocity was 600 mL·h -1 ·g -1 , and the desulfurization and dechlorination effects of the adsorbent were determined by detecting the COS and HCl concentrations at the reactor outlet. In this experiment, a GC9790Plus model chromatograph was used to detect the concentration of COS at the outlet, and the HCl concentration was determined in accordance with Standard HJ549-2016.

[0053] Calculate the adsorption rate A (%) of COS or HCL according to Equation (1).

[0054] A = ( C t -C o ) ∕ C o Equation (1) In Equation (1), C0 and C t are the concentrations of COS or HCL in the gas at the reactor inlet and the outlet after 3 h, respectively.

[0055] According to the above method for determining the desulfurization and dechlorination effects of the adsorbent, the adsorbents prepared in Examples 1-8 were subjected to adsorption effect detection, and the specific detection results are shown in Table 1.

[0056] Table 1 It can be seen from the detection results of the above data that when the modification order of dopamine and metal salt solution in the preparation process of the adsorbent changes, the adsorption effects of the finally prepared adsorbent on both COS and HCL are significantly affected, and the adsorption effect is significantly reduced.

[0057] When the concentration of phosphoric acid in the metal salt solution is decreased, the adsorption effect of the final adsorbent on carbonyl sulfide is somewhat reduced. Meanwhile, when stannous chloride pentahydrate is not added to the metal salt solution, the adsorption effect of the prepared adsorbent on HCl is significantly reduced. This indicates that during the entire preparation process of the adsorbent, the components in the metal salt solution have a synergistic effect in adsorbing carbonyl sulfide and HCl chloride, and only when these components all exist and are within a certain range can a relatively good adsorption effect be exhibited.

[0058] In order to further detect the influence of various conditions during the preparation of the adsorbent on the adsorption effect of the final adsorbent, the specific surface area and average pore diameter of the adsorbents in Examples 1 - 8 were specifically detected, and the specific results are summarized in Table 2 below.

[0059] Table 2 Combining the adsorbent specific surface area data and average pore diameter data in Table 2 above with the adsorbent adsorption effect data in Table 1 above, it can be seen that during the aging process, when ethyl acetoacetate was not added, the change in the specific surface area of the adsorbent was not significant, but the average pore diameter of the adsorbent decreased; while during the dopamine modification process, when the concentration of polypropylene grafted maleic anhydride added decreased, the specific surface area of the adsorbent decreased somewhat, but the influence on the average pore diameter was not significant.

[0060] However, changing the modification order of polydopamine and the metal salt solution has a relatively obvious influence on both the specific surface area and pore diameter of the adsorbent. This is mainly because after the molecular sieve is modified with polydopamine, a porous film is formed on the outer surface of the molecular sieve, which can enable more metal salt solution to be loaded onto the molecular sieve. If the impregnation of the metal salt solution is carried out first and then the polydopamine modification is carried out, the polydopamine will cover some of the already loaded metal salt components, thereby affecting and reducing both the specific surface area and pore diameter of the finally prepared adsorbent, which also corresponds to the situation of the adsorbent adsorption effect in Table 1 above.

[0061] In order to detect the optimal adsorption temperature of the adsorbent, the adsorption temperature was set at three temperature gradients of 30°C, 50°C, and 100°C, and the adsorption effect of the adsorbent when adsorbing for 0.5 h was detected. The specific results are shown in Table 3 below. [[ID=!7]]

[0062] Table 3 According to the detection results in Table 3 above, the adsorbent prepared in this application can maintain a good adsorption effect between 50°C and 100°C. In contrast, under the condition of 30°C, the adsorption performance of the adsorbent cannot be highlighted.

Claims

1. A preparation method of an adsorbent for dechlorination and desulfurization of blast furnace gas, characterized in that, The method comprises the following steps: Sodium aluminate is added to an alkaline solution to obtain an aluminum solution, and silica sol is added to an alkaline solution to obtain a silicon solution. The aluminum solution and the silica sol are mixed and then aged; After aging is completed, crystallization, drying and then calcination are carried out, and then grinding is performed to obtain a molecular sieve powder; The molecular sieve powder is successively placed in a dopamine solution and a metal salt solution containing phosphoric acid for two impregnations. After the impregnation is completed, calcination is carried out to obtain a modified molecular sieve adsorbent.

2. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 1, characterized in that, The alkaline solution is prepared by dissolving sodium hydroxide in deionized water. The mass ratio of sodium hydroxide, sodium aluminate, silica sol and deionized water is 4:0.08 - 0.12:4 - 8:

65.

3. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 1, characterized in that, The aging temperature is 60 °C, and the aging time is 80 - 100 h; The pressure during the crystallization process is 1.5 MPa, the temperature is 80 °C, and the crystallization time is 24 - 48 hours; Ethyl acetoacetate is added during both the aging and crystallization processes. The amount of ethyl acetoacetate added during aging is 2 - 5% of the volume of the silica sol, and the volume of ethyl acetoacetate added during the crystallization process is the same as that added during aging.

4. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 1, characterized in that, The dopamine solution is prepared by dissolving dopamine powder in 10 mM Tris-HCl buffer solution. The pH of the Tris-HCl buffer solution is 8 - 9, and the mass concentration of the dopamine solution is 2 - 5 g / L; Polypropylene grafted maleic anhydride is also added to the dopamine solution.

5. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 4, characterized in that, The concentration of polypropylene grafted maleic anhydride in the dopamine solution is 0.2 - 0.5 g / L.

6. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 1, characterized in that, The impregnation process of the dopamine solution is carried out at room temperature for 72 hours. After the impregnation is completed, it is washed with deionized water, and after the washing is completed, drying treatment is carried out to obtain a polydopamine-modified molecular sieve.

7. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 1, characterized in that, Zinc chloride, zirconium nitrate and tin tetrachloride are dissolved in water to prepare a metal salt solution, and phosphoric acid is added to the metal salt solution to prepare a metal salt solution containing phosphoric acid. The concentration of phosphoric acid in the metal salt solution is 1 - 5 g / L.

8. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 7, characterized in that, The atomic ratio of zinc, zirconium and tin in zinc chloride, zirconium nitrate and tin tetrachloride is (1.3 - 2.4):1:(0.1 - 0.5).

9. The preparation method of the adsorbent for dechlorination and desulfurization of blast furnace gas according to claim 6, characterized in that, The impregnation process of the metal salt solution containing phosphoric acid is specifically as follows: The polydopamine-modified molecular sieve is placed in the metal salt solution containing phosphoric acid for isovolumetric impregnation. The impregnation time is 15 - 24 hours. After the impregnation is completed, it is dried, and then calcined at 400 °C for 4 h. After calcination, it is taken out and placed in the metal salt solution containing phosphoric acid again for isovolumetric impregnation. The impregnation time is 20 - 48 hours. After the impregnation is completed, it is dried at 90 °C for 5 hours, and then calcined at 400 °C for 5 h in an air atmosphere.

10. A modified molecular sieve adsorbent for removing chlorine and sulfur from blast furnace gas prepared by the preparation method according to any one of claims 1 - 9 above.

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