A fluidized bed fly ash-based nano-silicon & iron binary gel, its preparation method and application

Abstract

This invention discloses a fluidized bed fly ash-based nano-silicon & iron binary gel, its preparation method, and its application. Fluidized bed fly ash and sodium hydroxide are uniformly mixed at a mass ratio of 1:0.5-1:1.5 and then calcined. The calcined product is mixed with hydrochloric acid at a solid-liquid ratio of 1g:5ml-1g:10ml, stirred, and then vacuum filtered to obtain a silicon & iron sol. The silicon & iron sol is mixed with propylene oxide at a volume ratio of 3:1-5:1, stirred evenly, and allowed to stand for gelation. After gelation, it is subjected to aging, displacement, and drying processes. Through a sodium-calcination-acid leaching process, a composite precursor containing silicon and iron is obtained. The silicon and iron precursors are co-hydrolyzed and then condensed to form a three-dimensional network, achieving a full composite of silicon oxide and iron oxide. In the formed gel, both silicon oxide and iron oxide are in an amorphous state, and their crystal structure results in highly unsaturated atomic coordination, thus giving it a high adsorption capacity.

Description

Technical Field

[0001] This invention belongs to the field of high-value utilization of solid waste, and relates to a fluidized bed fly ash-based nano-silicon & iron binary gel, its preparation method and application. Background Technology

[0002] Antimony belongs to Group 5 elements and is an important strategic metal. More than 120 antimony-containing minerals have been identified worldwide, of which more than ten are industrially usable. Through human activities such as mining and smelting antimony-containing minerals, burning antimony-containing fossil fuels, and industrial emissions, antimony can enter the atmosphere, soil, and aquatic environment, exhibiting strong toxicity, bioaccumulation, and carcinogenicity. In the natural environment, antimony mainly exists in the trivalent form (Sb(OH)3, Sb(OH)2). + and Sb(OH)4 - ) and pentavalent (Sb(OH)6) - Antimony exists in the form of sulfhydryl groups in the human body. Antimony and its compounds can bind to sulfhydryl groups, interfering with the activity of biological enzymes or disrupting ion balance, thereby causing metabolic disorders and damage to multiple systems and organs.

[0003] Iron oxides are commonly used as adsorbents in water treatment due to their high surface charge and specific surface area. Although iron oxides exhibit excellent adsorption performance and high affinity for metal ions and organic matter, they are loose, easily hydrolyzed, and amorphous flocculants with extremely poor water conductivity, making dewatering difficult and increasing sludge volume and treatment costs. A solution to this problem is to load iron oxides onto a carrier to stabilize their structure and facilitate solid-liquid separation. Zhu et al. first used an in-situ co-precipitation method to load Fe3O4 onto halloysite nanotubes (HNTs) to prepare HNTs / Fe3O4; Yu et al. used carbon nanotubes to load Fe2O3 to prepare a novel composite material, improving the specific surface area and dispersibility of Fe2O3; Xu Guangmei used quartz sand to load iron hydroxyl oxide to prepare an HFO-quartz sand composite material, which was then used for the adsorption of Sb(III) in water.

[0004] Because basic elements such as iron and silicon are abundant in soil and rocks, iron oxides and silicon oxides often coexist in various minerals and interact with each other. Related studies have found that silicon oxides and iron oxides have strong binding forces in some minerals. In primary minerals containing both ferrohydrate and silicon oxides, silicon oxides can adsorb onto the surface of the ferrohydrate. Furthermore, some studies have found that adding a certain amount of silicon oxide to ferrohydrate-containing minerals can improve the aggregation of iron oxide particles and increase the specific surface area of ​​the mineral. Therefore, the doping of silicon oxides may expose more adsorption sites for amorphous iron oxides, thereby further improving the adsorption performance of the material.

[0005] Silica aerogel, as a lightweight porous material, possesses a high specific surface area, thus showing potential as a support for iron oxides. Furthermore, silicon oxides have the property of inhibiting the morphological transformation of iron oxides, so a one-step synthesis of a silicon & iron composite aerogel can overcome the shortcomings of using iron oxides in adsorption. The silicon source for silica aerogels is generally organic or composite silicon source, which are expensive, increasing the preparation cost. Moreover, conventional iron oxide adsorbents have a relatively low maximum adsorption capacity for antimony, reaching only 30.9 mg / g, which fails to meet current requirements. Summary of the Invention

[0006] The purpose of this invention is to overcome the shortcomings of the prior art and provide a fluidized bed fly ash-based nano-silicon & iron binary gel, its preparation method and application, which improves the maximum adsorption capacity of antimony adsorbent and greatly reduces the cost.

[0007] To achieve the above objectives, the present invention employs the following technical solution:

[0008] A method for preparing fluidized bed fly ash-based nano-silicon & iron binary gel includes the following steps:

[0009] S1, Fluidized bed fly ash and sodium hydroxide are uniformly mixed in a mass ratio of 1:0.5-1:1.5 and then calcined;

[0010] S2, the calcined product is mixed with hydrochloric acid in a solid-liquid ratio of 1g:5ml-1g:10ml, stirred and then vacuum filtered to obtain silicon and iron sol.

[0011] S3, mix the silicon & iron sol with propylene oxide in a volume ratio of 3:1-5:1, stir well and let stand until gelation.

[0012] S4, after gelation, is subjected to aging, displacement and drying in sequence to obtain fluidized bed fly ash-based nano-silicon & iron binary gel.

[0013] Preferably, before S1, the fluidized bed fly ash is subjected to gravity sedimentation classification and divided into multiple grades according to the particle size range to obtain fluidized bed fly ash of different grades. The fluidized bed fly ash of the smallest particle size range is used for subsequent treatment.

[0014] Furthermore, in S1, the calcination process is as follows: the temperature is increased to 350-650℃ at a rate of 10℃ / min, and then held at 350-650℃ for 1-3 hours.

[0015] Preferably, the concentration of hydrochloric acid in S2 is 4-6 mol / L.

[0016] Preferably, in S2, the stirring speed is 300-500 rpm and the stirring time is 30-90 min.

[0017] Preferably, the specific process of S4 is as follows: after the gel is sealed and aged at room temperature for 3-9 hours, an equal volume of ethanol is added, and the gel is replaced at 40-80℃ for 6-18 hours. After the replacement is completed, the gel is filtered, and the remaining solid is dried at 40-80℃ for 8-16 hours to obtain fluidized bed fly ash-based nano-silicon & iron binary gel.

[0018] Preferably, the fluidized bed fly ash has the following composition: 59.6 wt% SiO2, 7.65 wt% Fe2O3, 19.9 wt% Al2O3, 4.59 wt% CaO, and 1.17 wt% MgO.

[0019] A fluidized bed fly ash-based nano-silicon & iron binary gel prepared by the above preparation method.

[0020] Application of the fluidized bed fly ash-based nano-silicon & iron binary gel as an antimony adsorbent.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] This invention utilizes a sodium-calcination-acid leaching process to obtain a composite precursor containing silicon and iron. The silicon and iron precursors are then co-hydrolyzed and subsequently condensed to form a three-dimensional network, achieving a full composite of silicon oxides and iron oxides. In the resulting silicon & iron binary gel, both silicon and iron oxides are amorphous, and their crystalline structure results in highly unsaturated atomic coordination, thus exhibiting high adsorption capacity. The maximum adsorption capacity reaches 65.79 mg / g, far exceeding the maximum adsorption capacity of conventional iron oxide adsorbents for antimony. Furthermore, the use of fluidized bed fly ash as a raw material significantly reduces costs. The full composite of silicon and iron oxides also overcomes the shortcomings of single iron oxides in adsorption applications, such as easy loosening and hydrolysis, poor water conductivity, increased sludge volume, and higher treatment costs. This invention broadens the application of fluidized bed fly ash-based composite materials in the field of heavy metal adsorption.

[0023] Furthermore, by utilizing the high pozzolanic activity of fluidized bed fly ash and its rich silicon and iron content, the fluidized bed fly ash is separated into different particle sizes through a gravity classification process. The high pozzolanic activity components are enriched in the small particle size products. The use of small particle size (high pozzolanic activity) products can reduce the temperature and alkali activator consumption during sodium roasting. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of gravity classification of fly ash in a fluidized bed according to the present invention;

[0025] Figure 2This is a scanning electron microscope image of the fluidized bed fly ash-based nano-silicon & iron binary gel obtained in Example 1 of the present invention.

[0026] Figure 3 The XRD pattern of the fluidized bed fly ash-based nano-silicon & iron binary gel obtained in Example 1 of the present invention;

[0027] Figure 4 The graph shows the adsorption performance of antimony on the fluidized bed fly ash-based nano-silicon & iron binary gel obtained in Example 1 of the present invention. Detailed Implementation

[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0029] It should be noted that the terms “front,” “back,” “left,” “right,” “up,” and “down” used in the following description refer to the directions shown in the attached diagram, while the terms “inside” and “outside” refer to the directions toward or away from the geometric center of a specific component, respectively.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. The terminology used herein in the specification of this invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The term "and / or" as used herein includes any and all combinations of one or more of the associated listed items.

[0031] The preparation method of fluidized bed fly ash-based nano-silicon & iron binary gel of the present invention uses fluidized bed fly ash, sodium hydroxide, hydrochloric acid, propylene oxide and ethanol as main raw materials. Through steps such as gravity classification of fluidized bed fly ash, high-temperature sodium calcination of fluidized bed fly ash, acid leaching and calcination of the product, and gelation of the acid leaching solution, a silicon & iron binary gel composite material is obtained. Specifically, the method includes the following steps:

[0032] Step 1: Gravity classification of fluidized bed fly ash.

[0033] like Figure 1As shown, a gravity classification device was used, which mainly consists of a mixing tank, six series-connected classification tubes, and a slurry pump. Fluidized bed fly ash was prepared into a 2% concentration slurry. The unit time water and ore feed rates inside the six classification tubes were set as shown in Table 1. Then, the water pump and feed pump were started sequentially to complete the equipment startup. After 48 hours, classification was completed, and the particles were divided into multiple grades according to their particle size from smallest to largest. The gravity sedimentation products were collected separately, filtered, dried, weighed, and bagged for later use. The products were named H1, H2, H3, H4, H5, H6, and H7, with H1 having the smallest particle size range and H7 the largest. Specifically, the particle size range for H1 was 0.82-3.13 nm, for H4 it was 2.35-6.64 nm, and for H7 it was 5.47-16.62 nm.

[0034] Table 1. Parameters of the sorting device in the gravity grading test

[0035]

[0036] Step 2: High-temperature sodium calcination of fluidized bed fly ash.

[0037] The product of H1 was selected for further steps. The product of H1 was mixed with sodium hydroxide at a mass ratio of 1:0.5-1:1.5 and placed in a tube furnace. The temperature was increased to 350-650℃ at 10℃ / min and held at 350-650℃ for 1-3 hours to obtain the calcined product.

[0038] Step 3: Acid leaching and roasting of the product.

[0039] Prepare 4-6 mol / L hydrochloric acid in advance, mix the calcined product with 4-6 mol / L hydrochloric acid at a solid-liquid ratio of 1g:5ml-1g:10ml, stir with a magnetic stirrer at 300-500 rpm for 30-90 min, and then vacuum filter to obtain silicon and iron sol.

[0040] Step 4: Silicon & Iron Gel.

[0041] Mix the silica and iron sol with propylene oxide at a volume ratio of 3:1 to 5:1, stir well, and let stand until gelation occurs.

[0042] Step 5: Aging, replacement, and drying of the gel.

[0043] The formed gel is sealed and aged at room temperature for 3-9 hours, then an equal volume of ethanol is added, and the mixture is displaced at 40-80℃ for 6-18 hours. After the displacement is completed, the mixture is filtered, and the remaining solid is dried at 40-80℃ for 8-16 hours. This yields a fluidized bed fly ash-based nano-silicon & iron binary gel.

[0044] The composition of the above-mentioned fluidized bed fly ash is as follows: 59.6 wt% SiO2, 7.65 wt% Fe2O3, 19.9 wt% Al2O3, 4.59 wt% CaO and 1.17 wt% MgO.

[0045] The prepared fluidized bed fly ash-based nano-silicon & iron binary gel was used as an antimony adsorbent for antimony adsorption.

[0046] Example 1

[0047] Step 1: Gravity classification of fluidized bed fly ash.

[0048] Fluidized bed fly ash was prepared into a 2% concentration slurry. The unit time water supply and feed rate inside the six separation pipes were set as shown in Table 1. Then, the water pump and feed pump were started sequentially to complete the equipment startup. After 48 hours, the classification was completed. The gravity sedimentation products were collected separately, filtered, dried, weighed, and bagged for later use. The products were numbered H1, H2, H3, H4, H5, H6, and H7, respectively.

[0049] Step 2: High-temperature sodium calcination of fluidized bed fly ash.

[0050] Select H1 to continue the subsequent steps. Mix H1 and sodium hydroxide in a 1:1 mass ratio and place them in a tube furnace. Heat the mixture to 550°C at 10°C / min and hold it at 550°C for 2 hours to obtain the calcined product.

[0051] Step 3: Acid leaching and roasting of the product.

[0052] Prepare 5 mol / L hydrochloric acid in advance, mix the calcined product with 5 mol / L hydrochloric acid at a solid-liquid ratio of 1 g: 7 ml, and stir with a magnetic stirrer at 300 rpm for 90 min to obtain silicon & iron sol.

[0053] Step 4: Silicon & Iron Gel.

[0054] Mix the silica & iron sol with propylene oxide at a volume ratio of 3:1, stir, and let stand until gelation occurs.

[0055] Step 5: Aging, replacement, and drying of the gel.

[0056] The formed gel was aged at room temperature in a sealed container for 9 hours, then an equal volume of ethanol was added, and the mixture was displaced at 60°C for 12 hours. After the displacement was completed, the mixture was filtered, and the remaining solid was dried at 60°C for 12 hours. This yielded a fluidized bed fly ash-based nano-silicon & iron binary gel, which was then used as a porous antimony adsorbent.

[0057] Figure 2The image shows a scanning electron microscope (SEM) image of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in Example 1. As can be seen from the image, the obtained fluidized bed fly ash-based high-efficiency porous antimony adsorbent is a nanomaterial composed of spherical nanoparticles with a diameter of approximately 20-30 nm. Uniformly distributed silica is assembled into a three-dimensional network with pores ranging from a few nanometers to over 100 nm.

[0058] Figure 3 The image shows the XRD pattern of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in Example 1. As can be seen from the image, the fluidized bed fly ash-based high-efficiency porous antimony adsorbent exhibits an amorphous state, with 26° representing the amorphous peak of silicon oxides and 35° and 62° representing the amorphous diffraction peaks of iron oxides.

[0059] Figure 4 The graph shows the adsorption performance of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in Example 1 for antimony. As can be seen from the graph, the maximum adsorption capacity of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent for Sb(V) is 65.79 mg / g.

[0060] The maximum adsorption capacity of existing antimony adsorbents α-FeO(OH) for Sb(V) is 27 mg / g; the maximum adsorption capacity of halloysite nanotube-supported Fe3O4 for Sb(V) is 30.5 mg / g; and the maximum adsorption capacity of copper-impregnated Fe3O4 for Sb(V) is 30.9 mg / g. Compared with other antimony adsorbents, the silicon & iron binary gel prepared in this invention has superior adsorption performance.

[0061] The fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in this embodiment has a specific surface area as high as 346.4 m². 2 / g, average pore size 4.42nm, yield 93.4%.

[0062] Example 2

[0063] Step 1: Gravity classification of fluidized bed fly ash

[0064] Fluidized bed fly ash was prepared into a 2% concentration slurry. The unit time water supply and feed rate inside the six separation pipes were set as shown in Table 1. Then, the water pump and feed pump were started sequentially to complete the equipment startup. After 48 hours, the classification was completed. The gravity sedimentation products were collected separately, filtered, dried, weighed, and bagged for later use. The products were numbered H1, H2, H3, H4, H5, H6, and H7, respectively.

[0065] Step 2: High-temperature sodium roasting of fluidized bed fly ash

[0066] Select H1 to continue the subsequent steps. Mix H1 and sodium hydroxide in a mass ratio of 1:0.5 and place them in a tube furnace. Heat the mixture to 450°C at a rate of 10°C / min and hold it at 450°C for 1 hour to obtain the calcined product.

[0067] Step 3: Acid leaching and roasting products

[0068] Prepare 4 mol / L hydrochloric acid in advance, mix the calcined product with 4 mol / L hydrochloric acid at a solid-liquid ratio of 1 g: 10 ml, stir with a magnetic stirrer at 500 rpm for 30 min, and then vacuum filter to obtain silicon and iron sol.

[0069] Step 4: Silicon & Iron Gel

[0070] Mix the silica & iron sol with propylene oxide at a volume ratio of 4:1, stir, and let stand until gelation occurs.

[0071] Step 5: Aging, replacement, and drying of the gel.

[0072] The formed gel was sealed and aged at room temperature for 3 hours, then an equal volume of ethanol was added, and the mixture was displaced at 70°C for 6 hours. After the displacement was completed, the mixture was filtered, and the remaining solid was dried at 50°C for 8 hours. This yielded a fluidized bed fly ash-based nano-silicon & iron binary gel, which was then used as a porous antimony adsorbent.

[0073] The yield of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in this embodiment was 64.2%.

[0074] Example 3

[0075] Step 1: Gravity classification of fluidized bed fly ash.

[0076] Fluidized bed fly ash was prepared into a 2% concentration slurry. The unit time water supply and feed rate inside the six separation pipes were set as shown in Table 1. Then, the water pump and feed pump were started sequentially to complete the equipment startup. After 48 hours, the classification was completed. The gravity sedimentation products were collected separately, filtered, dried, weighed, and bagged for later use. The products were numbered H1, H2, H3, H4, H5, H6, and H7, respectively.

[0077] Step 2: High-temperature sodium calcination of fluidized bed fly ash.

[0078] Select H1 to continue the subsequent steps. Mix H1 and sodium hydroxide in a mass ratio of 1:1.5 and place them in a tube furnace. Heat the mixture to 350°C at a rate of 10°C / min and hold it at 350°C for 2 hours to obtain the calcined product.

[0079] Step 3: Acid leaching and roasting of the product.

[0080] Prepare 5 mol / L hydrochloric acid in advance, mix the calcined product with 5 mol / L hydrochloric acid at a solid-liquid ratio of 1 g: 5 ml, stir with a magnetic stirrer at 400 rpm for 55 min, and then vacuum filter to obtain silicon and iron sol.

[0081] Step 4: Silicon & Iron Gel.

[0082] Mix the silica & iron sol with propylene oxide at a volume ratio of 5:1, stir, and let stand until gelation occurs.

[0083] Step 5: Aging, replacement, and drying of the gel.

[0084] The formed gel was aged at room temperature in a sealed container for 6 hours, then an equal volume of ethanol was added, and the mixture was displaced at 40°C for 18 hours. After the displacement was completed, the mixture was filtered, and the remaining solid was dried at 40°C for 16 hours. This yielded a fluidized bed fly ash-based nano-silicon & iron binary gel, which was then used as a porous antimony adsorbent.

[0085] The yield of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in this embodiment was 84.6%.

[0086] Example 4

[0087] Step 1: Gravity classification of fluidized bed fly ash.

[0088] Fluidized bed fly ash was prepared into a 2% concentration slurry. The unit time water supply and feed rate inside the six separation pipes were set as shown in Table 1. Then, the water pump and feed pump were started sequentially to complete the equipment startup. After 48 hours, the classification was completed. The gravity sedimentation products were collected separately, filtered, dried, weighed, and bagged for later use. The products were numbered H1, H2, H3, H4, H5, H6, and H7, respectively.

[0089] Step 2: High-temperature sodium calcination of fluidized bed fly ash.

[0090] Select H1 to continue the subsequent steps. Mix H1 and sodium hydroxide evenly at a mass ratio of 1:0.8 and place them in a tube furnace. Heat the mixture to 650°C at a rate of 10°C / min and hold it at 650°C for 3 hours to obtain the calcined product.

[0091] Step 3: Acid leaching and roasting of the product.

[0092] Prepare 6 mol / L hydrochloric acid in advance, mix the calcined product with 6 mol / L hydrochloric acid at a solid-liquid ratio of 1 g: 8 ml, stir with a magnetic stirrer at 300 rpm for 70 min, and then vacuum filter to obtain silicon and iron sol.

[0093] Step 4: Silicon & Iron Gel.

[0094] Mix the silica & iron sol with propylene oxide at a volume ratio of 3:1, stir, and let stand until gelation occurs.

[0095] Step 5: Aging, replacement, and drying of the gel.

[0096] The formed gel was sealed and aged at room temperature for 6 hours, then an equal volume of ethanol was added, and the mixture was displaced at 60°C for 12 hours. After the displacement was completed, the mixture was filtered, and the remaining solid was dried at 80°C for 12 hours. This yielded a fluidized bed fly ash-based nano-silicon & iron binary gel, which was then used as a porous antimony adsorbent.

[0097] The yield of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in this embodiment was 88.1%.

[0098] Example 5

[0099] Step 1: Gravity classification of fluidized bed fly ash.

[0100] Fluidized bed fly ash was prepared into a 2% concentration slurry. The unit time water supply and feed rate inside the six separation pipes were set as shown in Table 1. Then, the water pump and feed pump were started sequentially to complete the equipment startup. After 48 hours, the classification was completed. The gravity sedimentation products were collected separately, filtered, dried, weighed, and bagged for later use. The products were numbered H1, H2, H3, H4, H5, H6, and H7, respectively.

[0101] Step 2: High-temperature sodium calcination of fluidized bed fly ash.

[0102] Select H1 to continue the subsequent steps. Mix H1 and sodium hydroxide in a mass ratio of 1:1.2 and place them in a tube furnace. Heat the mixture to 350°C at a rate of 10°C / min and hold it at 350°C for 2 hours to obtain the calcined product.

[0103] Step 3: Acid leaching and roasting of the product.

[0104] Prepare 5 mol / L hydrochloric acid in advance, mix the calcined product with 5 mol / L hydrochloric acid at a solid-liquid ratio of 1 g: 8 ml, stir with a magnetic stirrer at 500 rpm for 60 min, and then vacuum filter to obtain silicon and iron sol.

[0105] Step 4: Silicon & Iron Gel.

[0106] Mix the silica & iron sol with propylene oxide at a volume ratio of 4:1, stir, and let stand until gelation occurs.

[0107] Step 5: Aging, replacement, and drying of the gel.

[0108] The formed gel was sealed and aged at room temperature for 6 hours, then an equal volume of ethanol was added, and the mixture was displaced at 40°C for 14 hours. After the displacement was completed, the mixture was filtered, and the remaining solid was dried at 60°C for 12 hours. This yields a fluidized bed fly ash-based high-efficiency porous antimony adsorbent.

[0109] The yield of the fluidized bed fly ash-based high-efficiency porous antimony adsorbent obtained in this embodiment was 76.9%.

[0110] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus.

[0111] It should be understood that the above description is for illustrative purposes and not for limitation. Many embodiments and applications beyond the provided examples will be apparent to those skilled in the art upon reading the above description. Therefore, the scope of this patent should not be determined by reference to the above description, but rather by reference to the foregoing claims and the full scope of their equivalents. For purposes of completeness, all articles and references, including patent applications and publications, are incorporated herein by reference. The omission of any aspect of the subject matter disclosed herein in the foregoing claims is not intended as a waiver of that subject matter, nor should it be construed as an indication that the applicant has not considered that subject matter as part of the disclosed inventive subject matter.

Claims

1. An application of a fluidized bed fly ash-based nano-silicon & iron binary gel as an antimony adsorbent, characterized in that, The preparation method of the fluidized bed fly ash-based nano-silicon & iron binary gel includes the following steps: S1, Fluidized bed fly ash and sodium hydroxide are uniformly mixed in a mass ratio of 1:0.5-1:1.5 and then calcined; The composition of fluidized bed fly ash is: 59.6 wt% SiO2, 7.65 wt% Fe2O3, 19.9 wt% Al2O3, 4.59 wt% CaO and 1.17 wt% MgO. S2, the calcined product is mixed with hydrochloric acid in a solid-liquid ratio of 1g:5ml-1g:10ml, stirred and then vacuum filtered to obtain silicon and iron sol. S3, mix the silicon & iron sol with propylene oxide in a volume ratio of 3:1-5:1, stir well and let stand until gelation. S4, after gelation, is subjected to aging, displacement and drying in sequence to obtain fluidized bed fly ash-based nano-silicon & iron binary gel.

2. The application of the fluidized bed fly ash-based nano-silicon & iron binary gel according to claim 1 as an antimony adsorbent, characterized in that, Before S1, the fluidized bed fly ash is classified by gravity sedimentation and divided into multiple grades according to the particle size range to obtain different grades of fluidized bed fly ash. The fluidized bed fly ash of the smallest particle size range is used for subsequent treatment.

3. The application of the fluidized bed fly ash-based nano-silicon & iron binary gel according to claim 2 as an antimony adsorbent, characterized in that, In S1, the calcination process is as follows: the temperature is increased to 350-650 ℃ at a rate of 10 ℃ / min, and then held at 350-650 ℃ for 1-3 hours.

4. The application of the fluidized bed fly ash-based nano-silicon & iron binary gel according to claim 1 as an antimony adsorbent, characterized in that, In S2, the concentration of hydrochloric acid is 4-6 mol / L.

5. The application of the fluidized bed fly ash-based nano-silicon & iron binary gel according to claim 1 as an antimony adsorbent, characterized in that, In S2, the stirring speed is 300-500 rpm and the stirring time is 30-90 min.

6. The application of the fluidized bed fly ash-based nano-silicon & iron binary gel according to claim 1 as an antimony adsorbent, characterized in that, The specific process for S4 is as follows: after aging the gel in a sealed container at room temperature for 3-9 hours, an equal volume of ethanol is added, and the gel is replaced at 40-80℃ for 6-18 hours. After the replacement is completed, the gel is filtered, and the remaining solid is dried at 40-80℃ for 8-16 hours to obtain a fluidized bed fly ash-based nano-silicon & iron binary gel.

Images