Preparation method of fluorine removal seed material for pellet reactor

Abstract

The present invention relates to the field of environmental engineering technology, and in particular to a method for preparing a fluorine removal seed material for a pellet reactor, comprising the following steps: (1) preparing a chitosan-based dispersion; (2) preparing materials; (3) dispersing and mixing; (4) spraying; and (5) drying. The present invention is mainly applied to seed crystals used in a pellet reactor. A pellet reactor based on the seed crystals prepared by the present invention can effectively remove fluoride ions in wastewater while recycling generated calcium fluoride crystals, and has important environmental and economic value. The pellet reactor seed crystal material prepared by the present invention helps to meet the development of industry and the improvement of environmental protection requirements, and promotes the application of pellet reactors in the treatment of fluorine-containing wastewater.

Description

Technical Field

[0001] The invention relates to the technical field of environmental engineering, in particular to a method for preparing a fluorine removal seed material for a pellet reactor. Background Art

[0002] The wastewater generated during the production process of industries such as chemical industry, nonferrous metallurgy, glass, electronics, and electroplating often contains high concentrations of fluoride, which causes serious fluoride pollution to the water environment. Therefore, the treatment technology of fluoride-containing wastewater has always been a key research topic in the field of environmental protection. In recent years, with the improvement of environmental protection requirements and the development of industry, new progress has been made in the treatment technology of fluoride-containing wastewater. At present, in addition to the traditional lime neutralization precipitation method and coagulation precipitation method, the lime neutralization precipitation method has problems such as difficulty in separating the colloidal CaF2 precipitation, unstable fluoride ion concentration in the effluent, and high water content of the CaF2 precipitate. The coagulation precipitation method has a narrow pH value requirement range for the dosing point, the fluoride ion removal effect is greatly affected by operational factors, the flocs are loose, the water content is high, and the cost of deep sludge treatment is high, which also affects the widespread application of this method.

[0003] The pelletized crystal reactor (PCR), a novel fluoride removal technology, induces calcium fluoride crystallization in water, not only reducing fluoride concentration but also producing high-purity calcium fluoride particles and minimizing byproduct production. Furthermore, my country faces insufficient reserves of fluorite, a mineral needed for industries such as electrolytic aluminum, glass etching, and fluorine chemicals. Fluorite has been designated a national strategic resource, and over 60% of fluorite ore must be imported. The PCR pellet technology developed by the company can achieve efficient crystallization and recovery of fluorine, addressing fluoride pollution while also enabling the recovery of high-purity calcium fluoride (artificial fluorite), thus addressing the issue of insufficient fluorite reserves, a national strategic resource.

[0004] Currently, the ideas for constructing crystal seeds suitable for PCR-induced crystallization are unclear and the effects are unstable. In order to promote the development of PCR technology, the development of new pellet reactor seeds has important scientific research and economic value. Summary of the Invention

[0005] In view of the problems existing in the prior art, the present invention provides a method for preparing a fluorine-removing seed material for a pellet reactor.

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

[0007] A method for preparing a fluorine removal seed material for a pellet reactor comprises the following steps:

[0008] (1) preparing a chitosan-based dispersion;

[0009] (2) Preparation of materials:

[0010] Weigh respectively: quartz sand, tourmaline powder, dolomite powder, fluorite powder;

[0011] (3) Dispersion mixing:

[0012] Tourmaline powder, dolomite powder and fluorite powder are mixed to obtain a mixed powder, and the mixed powder is evenly dispersed in a chitosan-based dispersion to obtain a spray coating;

[0013] (4) Spraying:

[0014] Spraying the spray coating obtained in step (3) onto the surface of quartz sand;

[0015] (5) Drying:

[0016] The sprayed quartz sand is dried to obtain the product.

[0017] As a further technical solution, the chitosan-based dispersion preparation method is:

[0018] First, an acetic acid solution is added to a reactor, and then the modified chitosan is added to the reactor, and stirred at room temperature until the modified chitosan is completely dissolved to obtain a modified chitosan solution;

[0019] Weigh dopamine, prepare an alkaline aqueous solution, add dopamine to the alkaline aqueous solution, stir and mix for 20 minutes to obtain a dispersion, and keep it warm in an ice bath for later use;

[0020] The alkaline aqueous solution is a sodium hydroxide solution, and the pH of the sodium hydroxide solution is 11;

[0021] The dopamine and alkaline aqueous solution are mixed in a mass ratio of 12-15 g: 200 mL;

[0022] Adding the dispersion and the additive to the modified chitosan solution, stirring and reacting for 8-10 hours at room temperature to obtain a chitosan-based dispersion;

[0023] The mixing mass ratio of the dispersion, the auxiliary agent and the modified chitosan solution is 3-5:0.1-0.16:15.

[0024] As a further technical solution, the modified chitosan solution is prepared as follows:

[0025] 15-17 g of modified chitosan was dissolved in 1% acetic acid solution to obtain a 15-17% (w / v) modified chitosan solution.

[0026] As a further technical solution, the modified chitosan preparation method is:

[0027] First, 2 g of chitosan was dissolved in 1% acetic acid solution to obtain a 2% (w / v) chitosan solution;

[0028] Then, 3,4-dihydroxybenzaldehyde is added to the ethanol solution, and stirred to mix uniformly to obtain a modified dispersion;

[0029] The mass fraction of the ethanol solution is 20%;

[0030] The mixing ratio of the 3,4-dihydroxybenzaldehyde and ethanol solution is 0.15g:10mL;

[0031] The chitosan solution is added to the reactor, and then an inert gas is introduced into the reactor to exhaust the air in the reactor, and then the modified dispersion obtained is obtained;

[0032] The molar ratio of chitosan to 3,4-dihydroxybenzaldehyde in the chitosan solution is 1:1.

[0033] As a further technical solution, the inert gas is any one of nitrogen and neon.

[0034] As a further technical solution, the auxiliary agent is a cross-linking agent, an initiator and an accelerator;

[0035] Among them, the crosslinker is MBA, the initiator is APS, and the accelerator is TEMED;

[0036] Among them, the mixing mass ratio of the crosslinking agent, initiator and accelerator is 10:1:1.2.

[0037] As a further technical solution, the mass ratio of quartz sand: tourmaline powder: dolomite powder: fluorite powder is 80-90:1-3:1-5:5-9.

[0038] As a further technical solution, the particle size of the quartz sand is 0.2±0.1 mm.

[0039] As a further technical solution, the mixing ratio of the mixed powder and the chitosan-based dispersion is: 18-20g:150mL.

[0040] As a further technical solution, drying is as follows: the sprayed quartz sand is placed in a cool and ventilated place, and after natural drying, it is stored at room temperature.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] The present invention is mainly applied to seed crystals used in pellet reactors. The pellet reactor based on the seed crystals prepared by the present invention can effectively remove fluoride ions from wastewater while recycling the generated calcium fluoride crystals, which has important environmental and economic value. The pellet reactor seed crystal material prepared by the present invention helps to meet the development of industry and the improvement of environmental protection requirements, and promotes the application of pellet reactors in the treatment of fluoride-containing wastewater.

[0043] The pellet reactor seed material prepared by the present invention is made of quartz sand, chitosan-based dispersion, tourmaline powder, dolomite powder, and fluorite powder. The surface of the quartz sand is sprayed evenly with tourmaline powder, dolomite powder, fluorite powder, and the like by utilizing the high viscosity of the chitosan-based dispersion through a spraying technology. After the composite material is naturally dried, it is stored at room temperature. The seed crystal has good chemical stability and can cope with various complex sewage environments.

[0044] Chitosan is derived from chitin, which is widely found in nature, through deacetylation. It is a renewable resource and meets environmental protection requirements. The chitosan-based dispersion prepared using chitosan as the raw material contains a large number of amino and hydroxyl functional groups in the polymer molecular structure. These functional groups enable chitosan to strongly interact with powders such as tourmaline powder, dolomite powder, and fluorite powder with quartz sand through hydrogen bonds, ionic bonds, or covalent bonds, thereby achieving a strong bonding effect. By introducing multiple groups to modify chitosan, the bonding performance can be improved, thereby achieving higher bonding stability during the seed material preparation process and significantly improving the overall performance of the seed crystal.

[0045] Tests have shown that the color of the pellet reactor seeds gradually changes from dark brown to off-white over time. Furthermore, microscopic observations reveal a gradually thickening transparent layer emerging from the opaque seed crystals, indicating the effective deposition of highly crystalline CaF2 crystals on the pellet reactor seeds. The crystal layer thickness reached 0.018±0.003 mm on day 3 and 0.043±0.007 mm on day 6. The crystallization kinetics formula, Y=0.0071*X-0.0009, demonstrates a linear deposition trend of CaF2 crystals on the pellet reactor seeds, with a deposition rate of up to 7.1 microns / day. This demonstrates that the pellet reactor seeds possess the kinetic properties required for efficient fluoride ion removal and enrichment. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0047] Figure 1 A general diagram of the pellet reactor seed;

[0048] Figure 2 This is a micrograph of the pellet reactor seed;

[0049] Figure 3 The morphology comparison of pellet reactor seeds that have not been crystallized, crystallized for 3 days, and crystallized for 6 days is shown;

[0050] Figure 4 This is a characterization diagram of the crystallization kinetics of pellet reactor seeds;

[0051] Figure 5 Scanning electron micrograph of pellet reactor seeds after 6 days of crystallization. DETAILED DESCRIPTION

[0052] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0053] In the embodiment of the present invention, the activated sludge used is the activated sludge from the aeration tank of a municipal sewage treatment plant.

[0054] Example 1

[0055] A method for preparing a fluorine removal seed material for a pellet reactor comprises the following steps:

[0056] (1) preparing a chitosan-based dispersion;

[0057] (2) Preparation of materials:

[0058] Weigh respectively: quartz sand, tourmaline powder, dolomite powder, fluorite powder;

[0059] (3) Dispersion mixing:

[0060] Tourmaline powder, dolomite powder and fluorite powder are mixed to obtain a mixed powder, and the mixed powder is evenly dispersed in a chitosan-based dispersion to obtain a spray coating;

[0061] (4) Spraying:

[0062] Spraying the spray coating obtained in step (3) onto the surface of quartz sand;

[0063] (5) Drying:

[0064] The sprayed quartz sand is dried to obtain the product.

[0065] The chitosan-based dispersion is prepared as follows:

[0066] First, an acetic acid solution is added to a reactor, and then the modified chitosan is added to the reactor, and stirred at room temperature until the modified chitosan is completely dissolved to obtain a modified chitosan solution;

[0067] Weigh dopamine, prepare an alkaline aqueous solution, add dopamine to the alkaline aqueous solution, stir and mix for 20 minutes to obtain a dispersion, and keep it warm in an ice bath for later use;

[0068] The alkaline aqueous solution is a sodium hydroxide solution, and the pH of the sodium hydroxide solution is 11;

[0069] The dopamine and alkaline aqueous solution are mixed in a mass ratio of 12 g: 200 mL;

[0070] Adding the dispersion and the additive to the modified chitosan solution, stirring and reacting for 8 hours at room temperature to obtain a chitosan-based dispersion;

[0071] The mixing mass ratio of the dispersion, the additive and the modified chitosan solution is 3:0.1:15.

[0072] The modified chitosan solution is prepared as follows:

[0073] 15 g of modified chitosan was dissolved in 1% acetic acid solution to obtain a 15% (w / v) modified chitosan solution.

[0074] The preparation method of modified chitosan is:

[0075] First, 2 g of chitosan was dissolved in 1% acetic acid solution to obtain a 2% (w / v) chitosan solution;

[0076] Then, 3,4-dihydroxybenzaldehyde is added to the ethanol solution, and stirred to mix uniformly to obtain a modified dispersion;

[0077] The mass fraction of the ethanol solution is 20%;

[0078] The mixing ratio of the 3,4-dihydroxybenzaldehyde and ethanol solution is 0.15g:10mL;

[0079] The chitosan solution is added to the reactor, and then an inert gas is introduced into the reactor to exhaust the air in the reactor, and then the modified dispersion obtained is obtained;

[0080] The molar ratio of chitosan to 3,4-dihydroxybenzaldehyde in the chitosan solution is 1:1.

[0081] The inert gas is nitrogen.

[0082] The auxiliary agents are cross-linking agents, initiators and accelerators;

[0083] Among them, the crosslinker is MBA, the initiator is APS, and the accelerator is TEMED;

[0084] Among them, the mixing mass ratio of the crosslinking agent, initiator and accelerator is 10:1:1.2.

[0085] The mass ratio of quartz sand: tourmaline powder: dolomite powder: fluorite powder is 80:1:1:5.

[0086] The particle size of quartz sand is 0.2±0.1 mm.

[0087] The mixing ratio of the mixed powder and the chitosan-based dispersion is: 18g:150mL.

[0088] Drying: Place the sprayed quartz sand in a cool and ventilated place, wait for it to dry naturally, and then store it at room temperature.

[0089] Example 2

[0090] A method for preparing a fluorine removal seed material for a pellet reactor comprises the following steps:

[0091] (1) preparing a chitosan-based dispersion;

[0092] (2) Preparation of materials:

[0093] Weigh respectively: quartz sand, tourmaline powder, dolomite powder, fluorite powder;

[0094] (3) Dispersion mixing:

[0095] Tourmaline powder, dolomite powder and fluorite powder are mixed to obtain a mixed powder, and the mixed powder is evenly dispersed in a chitosan-based dispersion to obtain a spray coating;

[0096] (4) Spraying:

[0097] Spraying the spray coating obtained in step (3) onto the surface of quartz sand;

[0098] (5) Drying:

[0099] The sprayed quartz sand is dried to obtain the product.

[0100] The chitosan-based dispersion is prepared as follows:

[0101] First, an acetic acid solution is added to a reactor, and then the modified chitosan is added to the reactor, and stirred at room temperature until the modified chitosan is completely dissolved to obtain a modified chitosan solution;

[0102] Weigh dopamine, prepare an alkaline aqueous solution, add dopamine to the alkaline aqueous solution, stir and mix for 20 minutes to obtain a dispersion, and keep it warm in an ice bath for later use;

[0103] The alkaline aqueous solution is a sodium hydroxide solution, and the pH of the sodium hydroxide solution is 11;

[0104] The mass ratio of the dopamine to the alkaline aqueous solution is 13 g: 200 mL;

[0105] The dispersion liquid and the additive are added to the modified chitosan solution, and the mixture is stirred and reacted for 9 hours at room temperature to obtain a chitosan-based dispersion liquid;

[0106] The mixing mass ratio of the dispersion, the additive and the modified chitosan solution is 4:0.12:15.

[0107] The modified chitosan solution is prepared as follows:

[0108] 16 g of modified chitosan was dissolved in 1% acetic acid solution to obtain a 16% (w / v) modified chitosan solution.

[0109] The preparation method of modified chitosan is:

[0110] First, 2 g of chitosan was dissolved in 1% acetic acid solution to obtain a 2% (w / v) chitosan solution;

[0111] Then, 3,4-dihydroxybenzaldehyde is added to the ethanol solution, and stirred to mix uniformly to obtain a modified dispersion;

[0112] The mass fraction of the ethanol solution is 20%;

[0113] The mixing ratio of the 3,4-dihydroxybenzaldehyde and ethanol solution is 0.15g:10mL;

[0114] The chitosan solution is added to the reactor, and then an inert gas is introduced into the reactor to exhaust the air in the reactor, and then the modified dispersion obtained is obtained;

[0115] The molar ratio of chitosan to 3,4-dihydroxybenzaldehyde in the chitosan solution is 1:1.

[0116] The inert gas is nitrogen.

[0117] The auxiliary agents are cross-linking agents, initiators and accelerators;

[0118] Among them, the crosslinker is MBA, the initiator is APS, and the accelerator is TEMED;

[0119] Among them, the mixing mass ratio of the crosslinking agent, initiator and accelerator is 10:1:1.2.

[0120] The mass ratio of quartz sand: tourmaline powder: dolomite powder: fluorite powder is 85:2:3:7.

[0121] The particle size of quartz sand is 0.2±0.1 mm.

[0122] The mixing ratio of the mixed powder and the chitosan-based dispersion is: 19g:150mL.

[0123] Drying: Place the sprayed quartz sand in a cool and ventilated place, wait for it to dry naturally, and then store it at room temperature.

[0124] Example 3

[0125] A method for preparing a fluorine removal seed material for a pellet reactor comprises the following steps:

[0126] (1) preparing a chitosan-based dispersion;

[0127] (2) Preparation of materials:

[0128] Weigh respectively: quartz sand, tourmaline powder, dolomite powder, fluorite powder;

[0129] (3) Dispersion mixing:

[0130] Tourmaline powder, dolomite powder and fluorite powder are mixed to obtain a mixed powder, and the mixed powder is evenly dispersed in a chitosan-based dispersion to obtain a spray coating;

[0131] (4) Spraying:

[0132] Spraying the spray coating obtained in step (3) onto the surface of quartz sand;

[0133] (5) Drying:

[0134] The sprayed quartz sand is dried to obtain the product.

[0135] The chitosan-based dispersion is prepared as follows:

[0136] First, an acetic acid solution is added to a reactor, and then the modified chitosan is added to the reactor, and stirred at room temperature until the modified chitosan is completely dissolved to obtain a modified chitosan solution;

[0137] Weigh dopamine, prepare an alkaline aqueous solution, add dopamine to the alkaline aqueous solution, stir and mix for 20 minutes to obtain a dispersion, and keep it warm in an ice bath for later use;

[0138] The alkaline aqueous solution is a sodium hydroxide solution, and the pH of the sodium hydroxide solution is 11;

[0139] The dopamine and alkaline aqueous solution are mixed in a mass ratio of 15 g:200 mL;

[0140] The dispersion liquid and the additive are added to the modified chitosan solution, and the mixture is stirred and reacted for 10 hours at room temperature to obtain a chitosan-based dispersion liquid;

[0141] The mixing mass ratio of the dispersion, the additive and the modified chitosan solution is 5:0.16:15.

[0142] The modified chitosan solution is prepared as follows:

[0143] 17 g of modified chitosan was dissolved in 1% acetic acid solution to obtain a 17% (w / v) modified chitosan solution.

[0144] The preparation method of modified chitosan is:

[0145] First, 2 g of chitosan was dissolved in 1% acetic acid solution to obtain a 2% (w / v) chitosan solution;

[0146] Then, 3,4-dihydroxybenzaldehyde is added to the ethanol solution, and stirred to mix uniformly to obtain a modified dispersion;

[0147] The mass fraction of the ethanol solution is 20%;

[0148] The mixing ratio of the 3,4-dihydroxybenzaldehyde and ethanol solution is 0.15g:10mL;

[0149] The chitosan solution is added to the reactor, and then an inert gas is introduced into the reactor to exhaust the air in the reactor, and then the modified dispersion obtained is obtained;

[0150] The molar ratio of chitosan to 3,4-dihydroxybenzaldehyde in the chitosan solution is 1:1.

[0151] The inert gas is nitrogen.

[0152] The auxiliary agents are cross-linking agents, initiators and accelerators;

[0153] Among them, the crosslinker is MBA, the initiator is APS, and the accelerator is TEMED;

[0154] Among them, the mixing mass ratio of the crosslinking agent, initiator and accelerator is 10:1:1.2.

[0155] The mass ratio of quartz sand: tourmaline powder: dolomite powder: fluorite powder is 90:3:5:9.

[0156] The particle size of quartz sand is 0.2±0.1 mm.

[0157] The mixing ratio of the mixed powder and the chitosan-based dispersion is: 20g:150mL.

[0158] Drying: Place the sprayed quartz sand in a cool and ventilated place, wait for it to dry naturally, and then store it at room temperature.

[0159] Comparative Example 1: This comparative example is basically the same as Example 2, except that the modified chitosan is replaced by untreated chitosan.

[0160] Comparative Example 2: This comparative example is basically the same as Example 2, except that the chitosan-based dispersion is replaced with a chitosan dispersion, and 15 g of modified chitosan is dissolved in a 1% acetic acid solution to obtain a 15% (w / v) chitosan dispersion solution.

[0161] Test experiment:

[0162] The artificial simulated wastewater (with an average fluoride ion concentration of about 150 mg·L -1 , pH is about 5), and the same pellet reactor containing equal amounts of the embodiment and comparative example seed crystals was used for treatment, and the fluoride ion content in the treated wastewater was compared, and the treatment defluorination rate was calculated. The results are shown in Table 1.

[0163] Table 1

[0164] Fluoride removal rate% Example 1 99.0 Example 2 99.8 Example 3 99.2 Comparative Example 1 95.2 Comparative Example 2 91.8

[0165] As shown in Table 1, the defluorination seeds for the pellet reactor prepared in the present invention have a high wastewater defluorination rate.

[0166] Morphological characterization of the pellet reactor seeds of Example 2

[0167] The basic structural characterization of pellet reactor seeds includes the following steps:

[0168] The basic structure of the pellet reactor seed was observed using a camera and an optical microscope. An appropriate amount of pellet reactor seed from Example 2 was weighed and laid flat on a clean white substrate. The overall structure was preliminarily characterized using a camera. Figure 1 Then, a small amount of the pellet reactor seed of Example 2 was spread on a glass slide, and its microstructure was characterized using an optical microscope, as shown in FIG. Figure 2 .

[0169] like Figure 1 As shown, the pellet reactor seeds appear dark brown to the naked eye. Figure 2 As shown in Figure 2, the pellet reactor seed has irregular morphology and low light transmittance. The above data show that the quartz sand surface has a sprayed composite inorganic material, indicating the successful preparation of the pellet reactor seed.

[0170] Crystallization Kinetics of Pellet Reactor Seeds in Example 2

[0171] Characterization of the pellet reactor seed crystallization kinetics includes the following steps:

[0172] The morphologies of pellet reactor seeds that were not crystallized, crystallized for 3 days, and crystallized for 6 days were characterized using a camera and an optical microscope. An appropriate amount of pellet reactor seeds were spread on a clean white substrate, and their general structure was preliminarily characterized using a camera. Subsequently, a small amount of pellet reactor seeds were spread on a glass slide, and their microstructure was characterized using an optical microscope. Figure 3 Subsequently, the images of crystallization seeds on different days were quantified using imageJ software, and the thickness of the transparent layer on the surface of the seeds was measured. An average of 20 cases were randomly sampled in each group. The data were plotted using Graphpad7.0, and the crystallization kinetics formula was calculated after linear fitting.

[0173] like Figure 3 As shown in the figure, the color of the pellet reactor seed gradually changes from dark brown to grayish white over time. In addition, the microscopic level shows that a gradually thickening transparent layer emerges from the surface of the opaque seed, indicating that highly crystalline CaF2 crystals are effectively deposited on the pellet reactor seed. Figure 4 As shown, the crystal layer thickness of the pellet reactor seed can reach 0.018±0.003 mm on the 3rd day, and the crystal layer thickness can reach 0.043±0.007 mm on the 6th day. The crystallization kinetic formula is Y=0.0071*X-0.0009, which shows that the CaF2 crystals have a linear deposition trend on the pellet reactor seed, and the deposition rate can reach 7.1 microns / day, indicating that the pellet reactor seed prepared by the present invention has kinetic properties that meet the requirements of efficient removal and enrichment of fluoride ions.

[0174] Ultramicrostructure of the pellet reactor seed crystals after crystallization in Example 2

[0175] The ultrastructural characterization of pellet reactor seeds after crystallization includes the following steps:

[0176] The ultramicroscopic morphology of pellet reactor seeds crystals crystallized for 6 days was characterized using scanning electron microscopy. The dried, 6-day-old pellet reactor seeds were affixed to conductive adhesive and gold-sprayed for 90 seconds to improve conductivity. The surface microstructure was then observed using a scanning electron microscope at an accelerating voltage of 20 kV.

[0177] like Figure 5 As shown, a regularly interlaced crystal structure can be seen on the surface of the pellet reactor seed crystals after 6 days of crystallization, indicating that highly crystallized CaF2 is deposited on the seed crystal surface, indicating that the CaF2 crystallization induced by the pellet reactor seed crystals has good performance and can be used as an alternative to artificial fluorite.

[0178] The preferred embodiments of the present invention disclosed above are intended only to help illustrate the present invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the present invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the content of this specification. These embodiments are selected and described in detail in this specification to better explain the principles and practical applications of the present invention, thereby enabling those skilled in the art to better understand and utilize the present invention. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for preparing a fluorine removal seed material for a pellet reactor, characterized in that: The following steps are involved: (1) preparing a chitosan-based dispersion; the chitosan-based dispersion preparation method is as follows: First, an acetic acid solution is added to a reactor, and then the modified chitosan is added to the reactor, and stirred at room temperature until the modified chitosan is completely dissolved to obtain a modified chitosan solution; Weigh dopamine, prepare an alkaline aqueous solution, add dopamine to the alkaline aqueous solution, stir and mix for 20 minutes to obtain a dispersion, and keep it warm in an ice bath for later use; The alkaline aqueous solution is a sodium hydroxide solution, and the pH of the sodium hydroxide solution is 11; The dopamine and alkaline aqueous solution are mixed in a mass ratio of 12-15 g: 200 mL; Adding the dispersion and the additive to the modified chitosan solution, stirring and reacting for 8-10 hours at room temperature to obtain a chitosan-based dispersion; The mixing mass ratio of the dispersion, the additive and the modified chitosan solution is 3-5:0.1-0.16:15; The modified chitosan preparation method is: First, 2 g of chitosan was dissolved in 1% acetic acid solution to obtain a 2% (w / v) chitosan solution; Then, 3,4-dihydroxybenzaldehyde is added to the ethanol solution, and stirred to mix uniformly to obtain a modified dispersion; The mass fraction of the ethanol solution is 20%; The mixing ratio of the 3,4-dihydroxybenzaldehyde and ethanol solution is 0.15g:10mL; The chitosan solution is added to the reactor, and then an inert gas is introduced into the reactor to exhaust the air in the reactor, and then the modified dispersion obtained is obtained; The chitosan solution has a molar ratio of chitosan to 3,4-dihydroxybenzaldehyde of 1:1; (2) Preparation of materials: Weigh respectively: quartz sand, tourmaline powder, dolomite powder, fluorite powder; (3) Dispersion mixing: Tourmaline powder, dolomite powder and fluorite powder are mixed to obtain a mixed powder, and the mixed powder is evenly dispersed in a chitosan-based dispersion to obtain a spray coating; (4) Spraying: Spraying the spray coating obtained in step (3) onto the surface of quartz sand; (5) Drying: The sprayed quartz sand is dried to obtain the product.

2. The method for preparing a fluorine removal seed material for a pellet reactor according to claim 1, characterized in that: The modified chitosan solution is prepared as follows: 15-17 g of modified chitosan was dissolved in 1% acetic acid solution to obtain a 15-17% (w / v) modified chitosan solution.

3. The method for preparing a fluorine removal seed material for a pellet reactor according to claim 1, characterized in that: The inert gas is any one of nitrogen and neon.

4. The method for preparing a fluorine removal seed material for a pellet reactor according to claim 1, characterized in that: The auxiliary agents are cross-linking agents, initiators and accelerators; Among them, the crosslinker is MBA, the initiator is APS, and the accelerator is TEMED; Among them, the mixing mass ratio of the crosslinking agent, initiator and accelerator is 10:1:1.

2.

5. The method for preparing a fluorine removal seed material for a pellet reactor according to claim 1, characterized in that: The mass ratio of the quartz sand: tourmaline powder: dolomite powder: fluorite powder is 80-90:1-3:1-5:5-9.

6. The method for preparing a fluorine removal seed material for a pellet reactor according to claim 5, characterized in that: The particle size of the quartz sand is 0.2±0.1 mm.

7. The method for preparing a fluorine removal seed material for a pellet reactor according to claim 1, characterized in that: The mixing ratio of the mixed powder and the chitosan-based dispersion is: 18-20 g: 150 mL.

8. The method for preparing a fluorine removal seed material for a pellet reactor according to claim 1, characterized in that: Drying: Place the sprayed quartz sand in a cool and ventilated place, wait for it to dry naturally, and then store it at room temperature.

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