CN111362712B - Ceramic fiber filtering material and preparation method thereof - Google Patents

Ceramic fiber filtering material and preparation method thereof Download PDF

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CN111362712B
CN111362712B CN202010191018.XA CN202010191018A CN111362712B CN 111362712 B CN111362712 B CN 111362712B CN 202010191018 A CN202010191018 A CN 202010191018A CN 111362712 B CN111362712 B CN 111362712B
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ceramic fiber
filter material
fiber
preparation
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CN111362712A (en
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傅超
郑维金
岳耀辉
鹿明
赵业娟
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Shandong Luyang Hot High Technology Ceramic Fiber Co
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Shandong Luyang Hot High Technology Ceramic Fiber Co
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01D—SEPARATION
    • B01D39/00—Filtering material for liquid or gaseous fluids
    • B01D39/14—Other self-supporting filtering material ; Other filtering material
    • B01D39/20—Other self-supporting filtering material ; Other filtering material of inorganic material, e.g. asbestos paper, metallic filtering material of non-woven wires
    • B01D39/2068—Other inorganic materials, e.g. ceramics
    • B01D39/2082—Other inorganic materials, e.g. ceramics the material being filamentary or fibrous
    • B01D39/2086—Other inorganic materials, e.g. ceramics the material being filamentary or fibrous sintered or bonded by inorganic agents
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B38/00—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof
    • C04B38/0051—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof characterised by the pore size, pore shape or kind of porosity
    • C04B38/0054—Porous mortars, concrete, artificial stone or ceramic ware; Preparation thereof characterised by the pore size, pore shape or kind of porosity the pores being microsized or nanosized
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/44—Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
    • C04B2235/444—Halide containing anions, e.g. bromide, iodate, chlorite
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/44—Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
    • C04B2235/449—Organic acids, e.g. EDTA, citrate, acetate, oxalate
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/48—Organic compounds becoming part of a ceramic after heat treatment, e.g. carbonising phenol resins
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/74—Physical characteristics
    • C04B2235/77—Density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance

Abstract

The present invention belongs to a ceramic fiberThe technical field, in particular to a ceramic fiber filtering material and a preparation method thereof. The preparation method provided by the invention comprises the following steps: a) mixing an aluminum source, silica sol and a spinning aid, and then hydrolyzing and concentrating to obtain a spinning solution; b) performing fiber forming and cotton collecting on the spinning solution to obtain a blank body; c) filling aluminum oxide aerogel in the blank, and then carrying out needling to obtain a needled fiber blank; d) and roasting the needled fiber blank to obtain the ceramic fiber filter material. Experimental results show that the porosity of the ceramic fiber filter material prepared by the method is more than 90%, the wind erosion resistance is more than 40m/s, the tensile strength is more than or equal to 0.1MPa, and the typical dust emission quantity can be controlled to be 5mg/nm3And (4) the following steps.

Description

Ceramic fiber filtering material and preparation method thereof
Technical Field
The invention belongs to the technical field of ceramic fibers, and particularly relates to a ceramic fiber filtering material and a preparation method thereof.
Background
Ceramic fiber filtration technology is one of the more rapidly developing filtration technologies in recent years. Compared with the traditional granular filter material, the fiber filter material has larger specific surface area, larger interface adsorption and capability of intercepting suspended matters, and good filtering effect. Compared with the traditional cloth bag and other filter materials, the fiber filter material can be used in a high-temperature environment; compared with porous ceramic and metal filter materials, the fiber filter material has the advantages of no need of sintering, low resistance, energy conservation, good chemical stability and thermal shock resistance. The ceramic fiber has excellent performance, so that the ceramic fiber can be widely applied to the aspects of air purification, high-temperature flue gas filtration, chemical filtration, diesel engine tail gas particle trapping, metal liquid filtration and the like, and is widely accepted particularly in the aspect of industrial waste gas treatment.
Chinese patent publication No. CN109734461A discloses a method for preparing a high-temperature resistant ceramic fiber filter tube, comprising the following steps: (1) dispersing the fiber in water, filtering, adding the modifier and the additive, and stirring; (2) drying the fiber after deslagging and modification; (3) adding water into an organic binder to prepare an organic binder solution, uniformly mixing the prepared organic binder solution, an inorganic binder and water, dividing the mixture into A, B parts, uniformly mixing A parts of mixed binder and fibers to obtain a mixed material a, adding an additive into the mixed material a, and uniformly mixing to obtain a mixed material b; (4) injecting the mixed material B and B parts of mixed binder into a mold for molding, and demolding to obtain a semi-finished product; (5) and (4) drying the semi-finished product in the step (4) to obtain a product.
Although the ceramic fiber filter material is prepared by the method disclosed by the patent, the method is a wet process, and the whole process flow is relatively complex; in addition, organic matters are used as a binder in the preparation process, so that the high-temperature stability of the product is relatively common. In addition, the existing preparation process of the ceramic fiber filter material has the problems of low mechanical strength, low porosity, poor filterability and the like.
Disclosure of Invention
In view of the above, the present invention aims to provide a ceramic fiber filter material and a preparation method thereof, the preparation method provided by the present invention has a simple process flow, and the ceramic fiber filter material prepared by the method has excellent heat resistance and mechanical strength, high porosity and strong filterability.
The invention provides a preparation method of a ceramic fiber filter material, which comprises the following steps:
a) mixing an aluminum source, silica sol and a spinning aid, and then hydrolyzing and concentrating to obtain a spinning solution;
b) performing fiber forming and cotton collecting on the spinning solution to obtain a blank body;
c) filling aluminum oxide aerogel in the blank, and then carrying out needling to obtain a needled fiber blank;
d) and roasting the needled fiber blank to obtain the ceramic fiber filter material.
Preferably, in the step a), the mass ratio of the aluminum source to the silica in the silica sol, calculated as alumina, is (67-95): (5-33).
Preferably, in the step a), the hydrolysis temperature is 40-70 ℃; the hydrolysis time is 1-2 h.
Preferably, in step a), the concentration mode is distillation concentration; the temperature for distillation and concentration is 80-150 ℃; the distillation and concentration time is 2-3 h.
Preferably, in step c), the density of the alumina aerogel is 3-500 kg/m3(ii) a The specific surface area of the alumina aerogel is 200-1000 m2(ii)/g; the porosity of the alumina aerogel is 80-99.8%; the aperture of the alumina aerogel is 1-100 nm.
Preferably, in step c), the specific manner of filling the aluminum oxide aerogel in the blank is as follows:
coating alumina aerogel on one side of the blank, and applying negative pressure to the other side; and the alumina aerogel enters the interior of the blank under the action of negative pressure.
Preferably, in step c), the coating amount of the alumina aerogel is 50-200 g/m2。
Preferably, in the step c), the needling density is 5-20 needles/cm2。
Preferably, in the step d), the roasting temperature is 700-900 ℃; the roasting time is 40-80 min.
The invention provides a ceramic fiber filter material prepared by the preparation method according to the technical scheme.
Compared with the prior art, the invention provides a ceramic fiber filter material and a preparation method thereof. The preparation method provided by the invention comprises the following steps: a) mixing an aluminum source, silica sol and a spinning aid, and then hydrolyzing and concentrating to obtain a spinning solution; b) performing fiber forming and cotton collecting on the spinning solution to obtain a blank body; c) filling aluminum oxide aerogel in the blank, and then carrying out needling to obtain a needled fiber blank; d) and roasting the needled fiber blank to obtain the ceramic fiber filter material. The preparation method provided by the invention is a dry process, only one-time heat treatment is involved in the preparation process, the process flow is simple, the main body of the prepared ceramic fiber filter material is of a fiber structure, and the porosity is high; meanwhile, organic components are not added in the preparation process of the method, so that the product has better high-temperature stability, and the maximum use temperature can reach 1600 ℃; in addition, the method provided by the invention also adopts alumina aerogel to feed into gaps (micron-sized) of the fiber blankFilling is carried out, so that the pore size of the fiber blank can be reduced, and the filterability of the product is improved; in addition, the method provided by the invention also utilizes a needling process to reinforce the product, thereby effectively improving the mechanical strength of the product. Experimental results show that the porosity of the ceramic fiber filter material prepared by the method is more than 90%, the wind erosion resistance is more than 40m/s, the tensile strength is more than or equal to 0.1MPa, and the typical dust emission quantity can be controlled to be 5mg/nm3And (4) the following steps.
Detailed Description
The technical solutions in the embodiments of the present invention are clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.
The invention provides a preparation method of a ceramic fiber filter material, which comprises the following steps:
a) mixing an aluminum source, silica sol and a spinning aid, and then hydrolyzing and concentrating to obtain a spinning solution;
b) performing fiber forming and cotton collecting on the spinning solution to obtain a blank body;
c) filling aluminum oxide aerogel in the blank, and then carrying out needling to obtain a needled fiber blank;
d) and roasting the needled fiber blank to obtain the ceramic fiber filter material.
In the preparation method provided by the invention, an aluminum source, silica sol and a spinning aid are mixed firstly. Wherein the aluminum source includes, but is not limited to, one or more of polyaluminum chloride sol, organic solution of aluminum acetylacetonate, aluminum isopropoxide, aluminum formate and aluminum acetate. In the present invention, the alumina (Al) of the polyaluminum chloride sol2O3) The solid content is preferably 20 to 30 wt%, specifically 20 wt%, 21 wt%, 22 wt%, 23 wt%, 24 wt%, 25 wt%, 26 wt%, 27 wt%, 28 wt%, 29 wt% or 30 wt%, and the source of the polyaluminum chloride sol is not particularly limited, and the polyaluminum chloride sol may be obtained as followsThe preparation method comprises the following steps:
mixing aluminum powder, hydrochloric acid and water, and heating for reaction to obtain the polyaluminium chloride sol.
In the preparation step of the polyaluminum chloride sol provided by the invention, the particle size of the aluminum powder is preferably 200-600 meshes, and specifically can be 200 meshes, 250 meshes, 300 meshes, 350 meshes, 400 meshes, 450 meshes, 500 meshes, 550 meshes or 600 meshes; the hydrochloric acid preferably participates in the mixing in the form of a hydrochloric acid aqueous solution, and the concentration of the hydrochloric acid aqueous solution is preferably 36-37 wt%, and specifically can be 36.5 wt%; the molar ratio of the aluminum powder to the hydrochloric acid is preferably (1.8-2.2): 1, specifically 1.8:1, 1.9:1, 2:1, 2.1:1 or 2.2: 1; the molar ratio of hydrochloric acid to water is preferably 1: (10-30), specifically 1:10, 1:11, 1:12, 1:13, 1:14, 1:15, 1:16, 1:17, 1:17.5, 1:18, 1:19, 1:20, 1:21, 1:22, 1:23, 1:24, 1:25, 1:26, 1:27, 1:28, 1:29, or 1: 30; the temperature of the heating reaction is preferably 60-100 ℃, and specifically can be 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, 95 ℃ or 100 ℃; the time of the heating reaction is not particularly limited, and the reaction is carried out until the solid content of alumina in the sol meets the requirement.
In the present invention, the concentration of the aluminum acetylacetonate organic solution is preferably 5 to 30 wt%, specifically 5 wt%, 10 wt%, 15 wt%, 20 wt%, 25 wt% or 30 wt%, and the source of the aluminum acetylacetonate organic solution is not particularly limited, and the aluminum acetylacetonate organic solution can be prepared by the following steps:
and mixing the aluminum acetylacetonate and the organic solvent to obtain the aluminum acetylacetonate organic solution.
In the above-mentioned step of preparing an organic solution of aluminum acetylacetonate provided by the present invention, the organic solvent is preferably N, N-Dimethylformamide (DMF); the mass ratio of the aluminum acetylacetonate to the organic solvent is preferably (1-2): (5-15).
In the preparation method provided by the invention, the pH value of the silica sol is preferably 2-4; the colloid particle size of the silica sol is preferably 10-20 nm; silicon dioxide (SiO) of the silica sol2) The solid content is preferably 15-30 wt%, specifically 15 wt%, 16 wt%, 17 wt%, 18 wt%, 19 wt%20, 21, 22, 23, 24, 25, 26, 27, 28, 29 or 30 wt%. In the present invention, the mass ratio of silica in the silica sol to the aluminum source in terms of alumina is preferably (5 to 33): (67-95), specifically 5:95, 15:85, 25:75 or 33: 67.
In the preparation method provided by the invention, the spinning aid preferably comprises polyvinyl alcohol; the polymerization degree of the polyvinyl alcohol is preferably 1000-3000, and specifically can be 1000, 1500, 2000, 2500 or 3000; the alcoholysis degree of the polyvinyl alcohol is preferably 80-99%, and specifically can be 80%, 82%, 85%, 87%, 90%, 92%, 95%, 97% or 99%; the viscosity of the polyvinyl alcohol at 25 ℃ is preferably 5.5-6.5 cps, specifically 5.5cps, 5.6cps, 5.7cps, 5.8cps, 5.9cps, 6cps, 6.1cps, 6.2cps, 6.3cps, 6.4cps or 6.5 cps; the pH value of the polyvinyl alcohol is preferably 5-7, and specifically can be 5, 5.5, 6, 6.5 or 7. In the present invention, the spinning aid is preferably mixed with the aluminum source and the silicon source in the form of an aqueous solution of the spinning aid; the concentration of the spinning assistant aqueous solution is preferably 6-10 wt%, and specifically can be 6 wt%, 6.5 wt%, 7 wt%, 7.5 wt%, 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt% or 10 wt%; the amount of the spinning aid is preferably 8 to 12 wt%, specifically 8 wt%, 8.5 wt%, 9 wt%, 9.5 wt%, 10 wt%, 10.5 wt%, 10.8 wt%, 11 wt%, 11.5 wt%, or 12 wt%, of the sum of the mass of the aluminum source and the mass of the silica in the silica sol, calculated as alumina.
In the preparation method provided by the invention, the aluminum source, the silica sol and the spinning aid are preferably mixed according to the following modes: firstly, mixing polyaluminium chloride sol and silica sol, and then adding a spinning aid into a mixed system of an aluminum source and the silica sol in the form of a spinning aid aqueous solution.
In the preparation method provided by the invention, after the polyaluminium chloride sol, the silica sol and the spinning aid are uniformly mixed, heating hydrolysis is carried out. Wherein the hydrolysis temperature is preferably 40-70 deg.C, specifically 40 deg.C, 41 deg.C, 42 deg.C, 43 deg.C, 44 deg.C, 45 deg.C, 46 deg.C, 47 deg.C, 48 deg.C, 49 deg.C, 50 deg.C, 51 deg.C, 52 deg.C, 53 deg.C, 54 deg.C, 55 deg.C, 56 deg.C, 57 deg.C, 58 deg.C, 59 deg.C, 60 deg.C, 61 deg.C, 62 deg.C, 63 deg.C, 64 deg.C, 66 deg.C, 67 deg.C, 68 deg.C, 69 deg.C or 70 deg.C; the hydrolysis time is preferably 1-2 h, and specifically can be 1h, 1.1h, 1.2h, 1.3h, 1.4h, 1.5h, 1.6h, 1.7h, 1.8h, 1.9h or 2 h. After the hydrolysis was completed, the mixture was concentrated. Wherein the concentration mode is preferably distillation concentration; the temperature of the distillation concentration is preferably 80-150 ℃, and specifically can be 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, 120 ℃, 125 ℃, 130 ℃, 135 ℃, 140 ℃, 145 ℃ or 150 ℃; the distillation and concentration time is preferably 2-3 h, and specifically can be 2h, 2.1h, 2.2h, 2.3h, 2.4h, 2.5h, 2.6h, 2.7h, 2.8h, 2.9h or 3 h. And after the concentration is finished, obtaining the spinning solution.
In the preparation method provided by the invention, after the spinning solution is obtained, the spinning solution is subjected to fiber forming treatment to form the fiber filaments. Wherein, the fiber-forming treatment mode is preferably filament-spinning fiber-forming. In the process of spinning, the rotating speed of the spinning disc is preferably controlled to be 1000-5000 r/min, and specifically can be 1000r/min, 1500r/min, 2000r/min, 2500r/min, 3000r/min, 3500r/min, 4000r/min, 4500r/min or 5000 r/min; the wind pressure is preferably controlled to be 130-160 Pa, and specifically 130Pa, 135Pa, 140Pa, 145Pa, 150Pa, 155Pa or 160 Pa; the temperature is preferably controlled at 30-70 deg.C, specifically 30 deg.C, 35 deg.C, 40 deg.C, 45 deg.C, 50 deg.C, 55 deg.C, 60 deg.C, 65 deg.C or 70 deg.C; the relative humidity is preferably controlled to be 20-40%, and specifically can be 20%, 25%, 30%, 35% or 40%.
In the preparation method provided by the invention, the fiber filaments formed by fiber forming treatment are uniformly cotton-gathered on a cotton-gathering mesh belt to obtain a blank. The thickness of the blank body is preferably 15-75 mm, and specifically can be 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm, 50mm, 55mm, 60mm, 65mm, 70mm or 75 mm.
In the preparation method provided by the invention, after a blank body is obtained, alumina aerogel is filled in the blank body. Wherein the density of the alumina aerogel is preferably 3-500 kg/m3Specifically, it may be 3kg/m3、5kg/m3、10kg/m3、20kg/m3、30kg/m3、40kg/m3、50kg/m3、100kg/m3、150kg/m3、200kg/m3、250kg/m3、300kg/m3、350kg/m3、400kg/m3、450kg/m3Or 500kg/m3(ii) a The specific surface area of the alumina aerogel is preferably 200-1000 m2A specific value of 200 m/g2/g、250m2/g、300m2/g、350m2/g、400m2/g、450m2/g、500m2/g、550m2/g、600m2/g、650m2/g、700m2/g、750m2/g、800m2/g、850m2/g、900m2/g、950m2In g or 1000m2(ii)/g; the porosity of the alumina aerogel is preferably 80-99.8%, and specifically can be 80%, 81%, 82%, 83%, 84%, 85%, 86%, 87%, 88%, 89%, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 99.8%; the pore diameter of the alumina aerogel is preferably 1-100 nm, and specifically can be 1nm, 5nm, 10nm, 15nm, 20nm, 25nm, 30nm, 35nm, 40nm, 45nm, 50nm, 55nm, 60nm, 65nm, 70nm, 75nm, 80nm, 85nm, 90nm, 95nm or 100 nm. In the present invention, the filling of the alumina aerogel is preferably performed in the following manner:
coating alumina aerogel on one side of the blank, and applying negative pressure to the other side; and the alumina aerogel enters the interior of the blank under the action of negative pressure.
In the above filling method provided by the present invention, the coating method is preferably spray coating; the coating weight of the alumina aerogel is preferably 50-200 g/m2Specifically, it may be 50g/m2、60g/m2、70g/m2、80g/m2、90g/m2、100g/m2、110g/m2、120g/m2、130g/m2、140g/m2、150g/m2、160g/m2、170g/m2、180g/m2、190g/m2Or 200g/m2(ii) a The specific operation steps of the filling are preferably as follows: placing the blank in a sealed space, in the blankOne side is coated with alumina aerogel, and the other side of the blank is sucked by a draught fan, so that the alumina aerogel enters the inside of the blank under the action of suction force. The suction strength of the induced draft fan is preferably 0.1-0.2 MPa, and specifically can be 0.1MPa, 0.11MPa, 0.12MPa, 0.13MPa, 0.14MPa, 0.15MPa, 0.16MPa, 0.17MPa, 0.18MPa, 0.19MPa or 0.2 MPa.
In the preparation method provided by the invention, after the alumina aerogel is filled, the blank body filled with the alumina aerogel is subjected to needling. Wherein the needling density is preferably 5-20 needles/cm2Specifically 5 needles/cm26 needles/cm27 needles/cm28 needles/cm29 needles/cm210 needles/cm211 needles/cm212 needles/cm213 needles/cm214 needles/cm215 needles/cm216 needles/cm217 needles/cm218 needles/cm219 needles/cm2Or 20 needles/cm2. And obtaining a needled fiber blank after the needling is finished.
In the preparation method provided by the invention, after the needled fiber blank is obtained, the needled fiber blank is roasted. Wherein the roasting temperature is preferably 700-900 ℃, and specifically can be 700 ℃, 710 ℃, 720 ℃, 730 ℃, 740 ℃, 750 ℃, 760 ℃, 770 ℃, 780 ℃, 790 ℃, 800 ℃, 810 ℃, 820 ℃, 830 ℃, 840 ℃, 850 ℃, 860 ℃, 870 ℃, 880 ℃, 890 ℃ or 900 ℃; the roasting time is preferably 40-80 min, and specifically can be 40min, 45min, 50min, 55min, 60min, 65min, 70min, 75min or 80 min. In the present invention, the needling fiber blank is preferably subjected to gradient temperature rise to reach the temperature required for calcination, and the gradient temperature rise process specifically includes: firstly, heating to 50-105 ℃ at a heating rate of 2-5 ℃/min, and removing adsorbed water contained in the fibers in the process; and then heating to the roasting temperature at the heating rate of 8-15 ℃/min. After the sintering, the ceramic fiber filter material is obtained.
The preparation method provided by the invention is a dry process, only one-time heat treatment is involved in the preparation process, the process flow is simple, the main body of the prepared ceramic fiber filter material is of a fiber structure, and the porosity is high; meanwhile, organic components are not added in the preparation process of the method, so that the product has better high-temperature stability, and the maximum use temperature can reach 1600 ℃; in addition, the method provided by the invention also adopts alumina aerogel to fill the gaps (micron-sized) of the fiber blank, thereby reducing the pore size of the fiber blank and improving the filterability of the product; in addition, the method provided by the invention also utilizes a needling process to reinforce the product, thereby effectively improving the mechanical strength of the product.
Experimental results show that the porosity of the ceramic fiber filter material prepared by the method is more than 90%, the wind erosion resistance is more than 40m/s, the tensile strength is more than or equal to 0.1MPa, and the typical dust emission quantity can be controlled to be 5mg/nm3And (4) the following steps.
The invention also provides a ceramic fiber filter material prepared by the method of the technical scheme.
The ceramic fiber filter material provided by the invention is prepared by the method; the density of the ceramic fiber filtering material is preferably 120-180 kg/m3Specifically, it may be 120kg/m3、125kg/m3、130kg/m3、135kg/m3、140kg/m3、145kg/m3、150kg/m3、155kg/m3、160kg/m3、165kg/m3、170kg/m3、175kg/m3Or 180kg/m3(ii) a The thickness of the ceramic fiber filtering material is preferably 10-50 mm, and specifically can be 10mm, 15mm, 20mm, 25mm, 30mm, 35mm, 40mm, 45mm or 50 mm; the porosity of the ceramic fiber filter material is preferably more than or equal to 90%, and can be 90%, 91%, 92%, 93%, 94% or 95%; the tensile strength of the ceramic fiber filter material is preferably more than or equal to 0.1MPa, and specifically can be 0.1MPa, 0.11MPa, 0.12MPa, 0.13MPa, 0.14MPa, 0.15MPa, 0.16MPa, 0.17MPa, 0.18MPa, 0.19MPa or 0.2 MPa.
The ceramic fiber filter material provided by the invention is prepared by the method provided by the invention, and has the advantages of excellent heat resistance and mechanical strength, high porosity and strong filterability.
For the sake of clarity, the following examples and comparative examples are given in detail below.
In the following examples and comparative examples of the present invention, the sources of the polyaluminum chloride sol, the acidic silica sol, and the alumina aerogel used were as follows:
1) polyaluminum chloride sol: mixing aluminum powder (200 meshes), hydrochloric acid and distilled water according to a molar ratio of 2:1:23, heating and refluxing at 90 ℃ to obtain Al2O3Polyaluminum chloride sol with a content of 20 wt%.
2) Acid silica sol: pH 2-4, particle size 10-20 nm, SiO2Content 20 wt%, commercially available.
3) Alumina aerogel: density 250kg/m3Specific surface area of 600m2Per g, porosity 88%, pore size 55nm, commercially available.
Example 1
The ceramic fiber filter material is prepared according to the following steps:
(1) 3.75kg of polyaluminum chloride sol and 1.25kg of acidic silica sol are weighed and uniformly mixed to obtain silicon-aluminum mixed solution.
(2) Slowly dissolving polyvinyl alcohol (with polymerization degree of 2000 and alcoholysis degree of 88%) at 95 deg.C to obtain 8% solution; and weighing 1kg of polyvinyl alcohol aqueous solution, and adding the polyvinyl alcohol aqueous solution into the silicon-aluminum mixed solution.
(3) And (3) uniformly stirring the mixed solution, hydrolyzing at 50 ℃ for 2h, heating to 120 ℃, distilling and concentrating for 2.5h to obtain a transparent and uniform silicon-aluminum composite spinning solution for later use.
(4) Spinning the silicon-aluminum composite spinning solution into fibers under the conditions that the spinning disc rotates at 3000r/min, the air pressure is 130Pa, the temperature is 70 ℃ and the relative humidity is 20%, and uniformly collecting cotton on a cotton collecting mesh belt by fiber yarns after fiber forming to obtain a fiber blank with the thickness of 45 mm.
(5) Spraying alumina aerogel on one side surface of the fiber blank in the sealed space, wherein the spraying density is 100g/m2Then, the other side of the fiber blank is sucked by an induced draft fan, the suction strength of the induced draft fan is 0.15MPa, and the alumina aerogel enters under the action of suction forceAnd (5) finishing filling the fiber blank.
(6) Needling the fiber blank filled with the alumina aerogel, wherein the needling density is 10 needles/cm2。
(7) And (3) heating the needled fiber blank to 105 ℃ at the heating rate of 5 ℃/min, removing adsorbed water contained in the fiber in the process, heating to 800 ℃ at the heating rate of 15 ℃/min, and roasting at the temperature for 60min to obtain the ceramic fiber filter material.
The ceramic fiber filter material prepared in this example had a thickness of 30mm and a density of 160kg/m3The porosity is 92%, and the pore size distribution is uniform.
The erosion resistance, tensile strength and typical dust emission quantity of the ceramic fiber filter material were measured. The wind erosion resistance refers to the wind speed corresponding to the crack or damage on the surface of the ceramic fiber filter material after the ceramic fiber filter material is exposed in compressed hot air (the wind temperature is 25 ℃, and the wind speed can be detected and adjusted), namely the maximum wind erosion speed which can be borne by the ceramic fiber filter material; the tensile strength is detected according to GB/T34219-2017 Experimental method for Normal temperature tensile strength of refractory materials; the typical dust emission quantity is obtained by online monitoring by using a laser dust detector.
The detection result is as follows: the wind erosion resistance is 43 m/s; the tensile strength is 0.15 MPa; typical dust emission amounts were 4.5mg/nm3。
Example 2
The ceramic fiber filter material is prepared according to the following steps:
(1) weighing 4.25kg of polyaluminum chloride sol and 0.75kg of acidic silica sol, and uniformly mixing the two to obtain a silicon-aluminum mixed solution.
(2) Slowly dissolving polyvinyl alcohol (with polymerization degree of 2000 and alcoholysis degree of 88%) at 95 deg.C to obtain 9% solution; 1.2kg of polyvinyl alcohol aqueous solution is weighed and added into the silicon-aluminum mixed solution.
(3) And (3) uniformly stirring the mixed solution, hydrolyzing at 50 ℃ for 2h, heating to 120 ℃, distilling and concentrating for 2.5h to obtain a transparent and uniform silicon-aluminum composite spinning solution for later use.
(4) Spinning the silicon-aluminum composite spinning solution into fibers under the conditions that the spinning disc rotates at 3000r/min, the air pressure is 130Pa, the temperature is 70 ℃ and the relative humidity is 20%, and uniformly collecting cotton on a cotton collecting mesh belt by fiber yarns after fiber forming to obtain a fiber blank with the thickness of 45 mm.
(5) Spraying alumina aerogel on one side surface of the fiber blank in the sealed space, wherein the spraying density is 100g/m2And then, the other side of the fiber blank is continuously sucked through the induced draft fan, the suction strength of the induced draft fan is 0.15MPa, and the alumina aerogel enters the inside of the fiber blank under the action of suction force to finish filling.
(6) Needling the fiber blank filled with the alumina aerogel, wherein the needling density is 10 needles/cm2。
(7) Heating the fiber blank subjected to needling to 105 ℃ at the heating rate of 5 ℃/min, and removing the adsorbed water contained in the fiber in the process; then heating to 800 ℃ at the heating rate of 15 ℃/min, and roasting for 60min at the temperature to obtain the ceramic fiber filter material.
The ceramic fiber filter material prepared in this example had a thickness of 30mm and a density of 160kg/m3The porosity is 92%, and the pore size distribution is uniform.
The weathering resistance, tensile strength and typical dust emission of the above ceramic fiber filter were measured according to the test method of example 1, and the results were: the wind erosion resistance is 45 m/s; the tensile strength is 0.13 MPa; typical dust emission amounts were 4.2mg/nm3。
Example 3
The ceramic fiber filter material is prepared according to the following steps:
(1) 3.75kg of polyaluminum chloride sol and 1.25kg of acidic silica sol are weighed and uniformly mixed to obtain silicon-aluminum mixed solution.
(2) Slowly dissolving polyvinyl alcohol (average polymerization degree of 2000 and alcoholysis degree of 88%) at 95 ℃ to obtain an aqueous solution of a solution with the mass fraction of 8%; weighing 1kg of polyvinyl alcohol aqueous solution, and adding the polyvinyl alcohol aqueous solution into the silicon-aluminum mixed solution.
(3) And (3) uniformly stirring the mixed solution, hydrolyzing at 50 ℃ for 2h, heating to 120 ℃, distilling and concentrating for 2.5h to obtain a transparent and uniform silicon-aluminum composite spinning solution for later use.
(4) Spinning the silicon-aluminum composite spinning solution into fibers at the spinning disc rotating speed of 2500r/min, the wind pressure of 150Pa, the temperature of 70 ℃ and the relative humidity of 30%, and uniformly collecting the fibers on a collecting mesh belt after fiber forming to obtain a fiber blank with the thickness of 45 mm.
(5) Spraying alumina aerogel on one side surface of the fiber blank in the sealed space, wherein the spraying density is 100g/m2And then, sucking the other side of the fiber blank by using an induced draft fan, wherein the suction strength of the induced draft fan is 0.15MPa, and the alumina aerogel enters the inside of the fiber blank under the action of suction force to finish filling.
(6) Needling the fiber blank filled with the alumina aerogel, wherein the needling density is 12 needles/cm2。
(7) And (3) heating the needled fiber blank to 105 ℃ at the heating rate of 5 ℃/min, removing adsorbed water contained in the fiber in the process, heating to 800 ℃ at the heating rate of 15 ℃/min, and roasting at the temperature for 60min to obtain the ceramic fiber filter material.
The ceramic fiber filter material prepared in this example had a thickness of 25mm and a density of 200kg/m3The porosity is 95 percent, and the pore size distribution is uniform.
The weathering resistance, tensile strength and typical dust emission of the above ceramic fiber filter were measured according to the test method of example 1, and the results were: the wind erosion resistance is 47 m/s; the tensile strength is 0.17MPa, and the typical dust emission quantity is 3.8mg/nm3。
Comparative example 1
The ceramic fiber filter material is prepared according to the following steps:
(1) 3.75kg of polyaluminum chloride sol and 1.25kg of acidic silica sol are weighed and uniformly mixed to obtain silicon-aluminum mixed solution.
(2) Slowly dissolving polyvinyl alcohol (average polymerization degree of 2000 and alcoholysis degree of 88%) at 95 ℃ to obtain an aqueous solution of a solution with the mass fraction of 8%; weighing 1kg of polyvinyl alcohol aqueous solution, and adding the polyvinyl alcohol aqueous solution into the silicon-aluminum mixed solution.
(3) And (3) uniformly stirring the mixed solution, hydrolyzing at 50 ℃ for 2h, heating to 120 ℃, distilling and concentrating for 2.5h to obtain a transparent and uniform silicon-aluminum composite spinning solution for later use.
(4) Spinning the silicon-aluminum composite spinning solution into fibers under the conditions that the spinning disc rotates at 3000r/min, the wind pressure is 120Pa, the temperature is 70 ℃ and the relative humidity is 20%, and uniformly collecting cotton on a cotton collecting mesh belt by fiber yarns after fiber forming to obtain a fiber blank with the thickness of 45 mm.
(5) Needling the fiber blank with the needling density of 10 needles/cm2。
(6) And (3) heating the needled fiber blank to 105 ℃ at the heating rate of 5 ℃/min, removing adsorbed water contained in the fiber in the process, heating to 800 ℃ at the heating rate of 15 ℃/min, and roasting at the temperature for 60min to obtain the ceramic fiber filter material.
The ceramic fiber filter material prepared in the comparative example had a thickness of 30mm and a density of 160kg/m3The porosity is 92%, and the pore size distribution is uniform.
The weathering resistance, tensile strength and typical dust emission of the above ceramic fiber filter were measured according to the test method of example 1, and the results were: the wind erosion resistance is 43 m/s; the tensile strength is 0.15 MPa; typical dust emission amounts were 6.3mg/nm3。
Comparative example 2
The ceramic fiber filter material is prepared according to the following steps:
(1) 3.75kg of polyaluminum chloride sol and 1.25kg of acidic silica sol are weighed and uniformly mixed to obtain silicon-aluminum mixed solution.
(2) Slowly dissolving polyvinyl alcohol (average polymerization degree of 2000 and alcoholysis degree of 88%) at 95 ℃ to obtain an aqueous solution of a solution with the mass fraction of 8%; and weighing 1kg of polyvinyl alcohol aqueous solution, and adding the polyvinyl alcohol aqueous solution into the silicon-aluminum mixed solution.
(3) And (3) uniformly stirring the mixed solution, hydrolyzing at 50 ℃ for 2h, heating to 120 ℃, distilling and concentrating for 2.5h to obtain a transparent and uniform silicon-aluminum composite spinning solution for later use.
(4) Spinning the silicon-aluminum composite spinning solution into fibers under the conditions that the spinning disc rotates at 3000r/min, the wind pressure is 120Pa, the temperature is 70 ℃ and the relative humidity is 20%, and uniformly collecting cotton on a cotton collecting mesh belt by fiber yarns after fiber forming to obtain a fiber blank with the thickness of 45 mm.
(5) Needling the fiber blank with the needling density of 10 needles/cm2。
(6) Spraying alumina aerogel on one side surface of the fiber blank in the sealed space, wherein the spraying density is 100g/m2And then, sucking the other side of the fiber blank by using an induced draft fan, wherein the suction strength of the induced draft fan is 0.15MPa, and the alumina aerogel enters the inside of the fiber blank under the action of suction force to finish filling.
(7) And (3) heating the fiber blank subjected to needling to 105 ℃ at the heating rate of 5 ℃/min, removing adsorbed water contained in the fiber in the process, heating to 1250 ℃ at the heating rate of 15 ℃/min, and roasting at the temperature for 60min to obtain the ceramic fiber filter material.
The ceramic fiber filter material prepared in the comparative example had a thickness of 30mm and a density of 160kg/m3The porosity is 91%, and the pore size distribution is uniform.
The weathering resistance, tensile strength and typical dust emission of the above ceramic fiber filter were measured according to the test method of example 1, and the results were: the wind erosion resistance of the product is 32 m/s; the tensile strength is 0.085 MPa; typical dust emission amounts were 7.0mg/nm3。
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.

Claims (9)

1. A preparation method of a ceramic fiber filter material comprises the following steps:
a) mixing an aluminum source, silica sol and a spinning aid, and then hydrolyzing and concentrating to obtain a spinning solution;
b) performing fiber forming and cotton collecting on the spinning solution to obtain a blank body;
c) filling aluminum oxide aerogel in the blank, and then carrying out needling to obtain a needled fiber blank;
d) roasting the needled fiber blank to obtain a ceramic fiber filter material;
in the step d), the roasting temperature is 700-900 ℃; the roasting time is 40-80 min.
2. The method according to claim 1, wherein in the step a), the mass ratio of the aluminum source to the silica in the silica sol is (67 to 95): (5-33).
3. The preparation method according to claim 1, wherein in the step a), the hydrolysis temperature is 40-70 ℃; the hydrolysis time is 1-2 h.
4. The method according to claim 1, wherein in step a), the concentration is carried out by distillation; the temperature for distillation and concentration is 80-150 ℃; the distillation and concentration time is 2-3 h.
5. The method according to claim 1, wherein the alumina aerogel has a density of 3 to 500kg/m in step c)3(ii) a The specific surface area of the alumina aerogel is 200-1000 m2(ii)/g; the porosity of the alumina aerogel is 80-99.8%; the aperture of the alumina aerogel is 1-100 nm.
6. The method for preparing according to claim 1, wherein in step c), the alumina aerogel is filled in the blank by:
coating alumina aerogel on one side of the blank, and applying negative pressure to the other side; and the alumina aerogel enters the interior of the blank under the action of negative pressure.
7. The method according to claim 6, wherein the amount of the alumina aerogel applied in step c) is 50 to 200g/m2。
8. The method according to claim 1, wherein the needling density in step c) is 5 to 20 needles/cm2。
9. A ceramic fiber filter material obtained by the method of any one of claims 1 to 8.
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