Recycling method of silicon-rich aluminum-containing material and material prepared by same

Abstract

The invention relates to the technical field of waste recycling, and discloses a recycling method of a silicon-rich aluminum-containing material and a material prepared from the silicon-rich aluminum-containing material, and the recycling method comprises the following steps: (1) mixing the silicon-rich aluminum-containing material, an active agent and water, and sequentially carrying out first drying and calcination to obtain an activated product; (2) mixing the activated product with water, adjusting to acidity, carrying out hydrolysis reaction, and then carrying out solid-liquid separation to obtain filtrate and filter residues; (3) converting the filtrate into silicon-aluminum aerogel and / or mullite whiskers; and (4) mixing the filter residues, strong base and water, and then sequentially carrying out first aging and second drying to obtain the zeolite. According to the method, the zeolite, the mullite whiskers and the silicon-aluminum aerogel are prepared by adopting different methods after the silicon-rich and aluminum-containing material is activated, so that the comprehensive, multi-body and high-value utilization of the silicon-rich and aluminum-containing material is realized, and the recycling rate of the silicon-rich and aluminum-containing material reaches 98% or above.

Description

Technical Field

[0001] The present invention relates to the technical field of waste recycling and reuse, and particularly to a method for recycling rich-silicon and aluminum-containing materials and materials prepared therefrom. Background Art

[0002] Rich-silicon and aluminum-containing materials, as industrial by-products, are mainly generated in production activities related to aluminosilicate minerals. These by-products may come from multiple links such as ore mining, smelting, processing, and chemical synthesis. For example, in the production process of aluminum fluoride, silicon slag, as a by-product, is mainly formed by the unstable decomposition of silicic acid released during the reaction of fluosilicic acid with aluminum hydroxide. And in the processes of zeolite synthesis, ceramic manufacturing, iron and steel smelting, and casting, a large amount of rich-silicon and aluminum-containing materials may also be generated.

[0003] If the rich-silicon and aluminum-containing materials cannot be reasonably disposed of, it will cause serious environmental pollution. For example, the accumulation of a large amount of solid waste will occupy precious land resources, and harmful substances in the waste may pollute the soil and water bodies through infiltration, leaching, etc. Dust and harmful gases may be generated during the stacking and disposal of the waste, affecting air quality, etc. Therefore, how to improve the utilization value of rich-silicon and aluminum-containing materials through reasonable recycling methods is an urgent problem to be solved by those skilled in the art. Summary of the Invention

[0004] In view of this, the present invention provides a method for recycling rich-silicon and aluminum-containing materials and materials prepared therefrom, so as to improve the utilization value of rich-silicon and aluminum-containing materials through this method and reduce the impact of solid waste accumulation on the environment.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a method for recycling rich-silicon and aluminum-containing materials, comprising the following steps:

[0007] (1) Mix the rich-silicon and aluminum-containing materials, an activator, and water, and then perform first drying and calcination in sequence to obtain an activated product;

[0008] (2) Mix the activated product and water, adjust to acidic, perform a hydrolysis reaction, and then perform solid-liquid separation to obtain a filtrate and a filter residue;

[0009] (3) Convert the filtrate into silica-alumina aerogel and / or mullite whiskers;

[0010] (4) Mix the filter residue, a strong base, and water, and then perform first aging and second drying in sequence to obtain zeolite.

[0011] Preferably, the mass ratio of the silicon-rich aluminous material, the activator and water in step (1) is 1:(0.5 - 1.2):5, and the activator includes one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium nitrate, potassium hydroxide, potassium carbonate, potassium bicarbonate, potassium nitrate, magnesium hydroxide, magnesium carbonate, magnesium nitrate, calcium hydroxide, calcium carbonate, calcium bicarbonate, calcium nitrate.

[0012] Preferably, the first drying temperature in step (1) is 60 - 150 °C.

[0013] Preferably, the calcination temperature in step (1) is 700 - 900 °C, and the calcination time is 1 - 5 h.

[0014] Preferably, before the calcination in step (1), the following step is also included: grinding the material after the first drying to a particle size ≤ 0.4 mm.

[0015] Preferably, the temperature of the hydrolysis reaction in step (2) is 20 - 80 °C.

[0016] Preferably, the mass ratio of the filter residue and the strong base in step (4) is 1:1 - 10, and the mass ratio of the filter residue and water is 1:0.8 - 1.2.

[0017] Preferably, the mixing in step (4) is heating and mixing, and the temperature of the heating and mixing is 60 - 180 °C.

[0018] Preferably, the first aging temperature in step (4) is 20 - 80 °C, and the first aging time is 2 - 48 h.

[0019] Preferably, the temperature of the second drying in step (4) is 60 - 180 °C.

[0020] Preferably, before the second drying in step (4), the following step is also included: adjusting the pH value of the material after aging to 7 - 8.

[0021] Preferably, the method for converting the filtrate into a silica-alumina aerogel is as follows: adjusting the pH of the filtrate to neutral, and then performing second aging and third drying in sequence to obtain the silica-alumina aerogel.

[0022] Preferably, the second aging temperature is 20 - 80 °C, and the second aging time is 2 - 48 h.

[0023] Preferably, the third drying is stepwise drying, and the stepwise drying is specifically: drying at a constant temperature of 20 - 60 °C for 1 - 10 h, drying at a constant temperature of 60 - 100 °C for 1 - 10 h, and drying at a constant temperature of 100 - 150 °C for 1 - 10 h.

[0024] Preferably, the method for converting the filtrate into mullite whiskers is as follows: the filtrate is mixed with an aluminum source supplement, a sintering aid, and an acid-base regulator, and then subjected to fourth drying and calcination in sequence to obtain mullite whiskers.

[0025] Preferably, the addition amount of the aluminum source supplement is 20-80% of the mass of the filtrate.

[0026] Preferably, the addition amount of the sintering aid is 3-25% of the mass of the filtrate.

[0027] Preferably, the addition amount of the acid-base regulator is 0.1-3% of the mass of the filtrate.

[0028] Preferably, the temperature of the fourth drying is 60-150 °C;

[0029] Preferably, the calcination temperature is 725-850 °C, and the calcination time is 1.5-3.5 h.

[0030] Preferably, before the calcination, the following steps are further included: grinding the material after the fourth drying to a particle size ≤ 0.4 mm.

[0031] Preferably, before converting the filtrate into silica-alumina aerogel and / or mullite whiskers, it further includes: filtering the filtrate through a cation exchange resin.

[0032] On the other hand, the present invention also provides a material prepared by the reuse method of the silicon-rich aluminum-containing material described in any one of the above, and the material includes zeolite, silica-alumina aerogel and / or mullite whiskers.

[0033] The present invention provides a reuse method of a silicon-rich aluminum-containing material. Compared with the prior art, its beneficial effects are as follows:

[0034] After the silicon-rich aluminum-containing material is activated in the present invention, zeolite, mullite whiskers and silica-alumina aerogel are prepared by different methods, realizing the all-round, multi-body and high-value utilization of the aluminum-rich silicon-containing material, and the recycling rate of the aluminum-rich silicon-containing material reaches more than 98%. Description of the Drawings

[0035] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained according to the provided drawings without creative efforts.

[0036] Figure 1 It is a scanning electron microscope image of the mullite whiskers prepared in Example 2 of the present invention;

[0037] Figure 2 It is the scanning electron microscope image of the zeolite prepared in Example 2 of the present invention;

[0038] Figure 3 It is the scanning electron microscope image of the silica-alumina aerogel prepared in Example 2 of the present invention;

[0039] Figure 4 It is the XRD pattern of the silica-alumina aerogel prepared in Example 1 and Comparative Example 1 of the present invention;

[0040] Figure 5 It is the XRD pattern of the mullite whiskers prepared in Example 1 and Comparative Example 2 of the present invention;

[0041] Figure 6 It is the spectrogram of the zeolite prepared in Example 1 and Comparative Example 3 of the present invention;

[0042] Figure 7 It is the finished product image of the mullite whiskers prepared in Example 1 of the present invention;

[0043] Figure 8 It is the finished product image of the mullite whiskers prepared in Comparative Example 2 of the present invention;

[0044] Figure 9 It is the finished product image of the aerogel prepared in Example 1 of the present invention;

[0045] Figure 10 It is the finished product image of the aerogel prepared in Comparative Example 1 of the present invention;

[0046] Figure 11 It is the finished product image of the zeolite prepared in Example 1 of the present invention;

[0047] Figure 12 It is the finished product image of the zeolite prepared in Comparative Example 3 of the present invention. Detailed implementation manners

[0048] The present invention will be described below through specific examples. Those skilled in the art can understand that the following specific examples are only for the purpose of illustration and do not limit the scope of the present invention in any way. Additionally, in the following examples, unless otherwise specified, the reagents and equipment used are commercially available. If the specific processing conditions and methods are not clearly described in the subsequent examples, the conditions and methods known in the art can be used for processing.

[0049] In one aspect of the present invention, a method for reusing silicon-rich aluminous materials is provided, including the following steps:

[0050] (1) Mix the silicon-rich aluminous material, the active agent, and water, and then successively perform the first drying and calcination to obtain an activated product;

[0051] (2) Mix the activated product and water, adjust to acidic, perform a hydrolysis reaction, and then perform solid-liquid separation to obtain a filtrate and a filter residue;

[0052] (3) Convert the filtrate into silicon-aluminum aerogel and / or mullite whiskers;

[0053] (4) Mix the filter residue, strong base, and water, and then successively perform the first aging and the second drying to obtain zeolite.

[0054] In the present invention, first, the silicon-rich aluminous material, the active agent, and water are mixed and then successively subjected to the first drying and calcination to obtain an activated product.

[0055] In some embodiments of the present invention, the mass ratio of the silicon-rich aluminous material, the active agent, and water is 1:(0.5 - 1.2):5. For example, it can be 1:0.5:5, 1:0.8:5, 1:1:5, 1:1.2:5, etc. Under the action of the active agent, the silicon-rich aluminous material can form meta-aluminosilicate that is soluble in acid. In addition, by adjusting the addition amount of the active agent, the generation amounts of the subsequent filter residue and filtrate can be adjusted. For example, if the addition amount of the active agent is less, more filter residue will be generated for preparing zeolite.

[0056] In some embodiments of the present invention, the silicon-rich aluminous material is a solid waste containing silicon dioxide, including one or more of diatomite, clay, kaolin, feldspar, nepheline syenite, shale, zeolite, opal, mullite, andalusite, epidote, cordierite, sphene, almandine, beryl, blue beryl, sillimanite, sillimanite, diopside, grossular, olivine, vesuvianite, wollastonite, serpentine, talc, chrysocolla, tremolite, basalt, andesite, trachyte, rhyolite, topaz, kyanite, bauxite, montmorillonite, mica, illite, vermiculite, sepiolite, chlorite, bauxite, obsidian, actinolite, pitchstone, perlite, pumice, silicon-aluminum ore, fly ash, zeolite, coal gangue, and silicon-aluminum gel residue; the active agent includes one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium nitrate, potassium hydroxide, potassium carbonate, potassium bicarbonate, potassium nitrate, magnesium hydroxide, magnesium carbonate, magnesium nitrate, calcium hydroxide, calcium carbonate, calcium bicarbonate, and calcium nitrate.

[0057] In some embodiments of the present invention, the silicon-rich aluminous material, the active agent, and water are mixed under magnetic stirring until homogeneous, the stirring speed is 100 - 1500 r / min. For example, it can be 100 r / min, 500 r / min, 1000 r / min, 1500 r / min, etc., and the mixing temperature is 20 - 50 °C. For example, it can be 20 °C, 30 °C, 40 °C, 50 °C, etc.

[0058] In some embodiments of the present invention, the temperature of the first drying is 60 - 150°C, for example, it can be 60°C, 80°C, 100°C, 120°C, 150°C, etc. Water is removed through drying. For the degree of drying, it is sufficient to dry to constant weight. The specific time can be adjusted according to the actual situation. As long as the drying method can achieve the purpose, such as forced air drying, vacuum drying, etc., no special limitation is imposed here.

[0059] In some embodiments of the present invention, the material after the first drying is ground to a particle size ≤ 0.4 mm and then calcined. The particle size can be, for example, 0.16 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, etc., to increase the specific surface area of the material and enhance the calcination activation effect.

[0060] In some embodiments of the present invention, the calcination temperature is 700 - 900°C and the calcination time is 1 - 5 h. Among them, the calcination temperature can be, for example, 700°C, 750°C, 800°C, 850°C, 900°C, etc., and the calcination time can be, for example, 1 h, 2 h, 3 h, 4 h, 5 h, etc. Under the action of the activator, meta - aluminosilicate salts that are soluble in acid can be generated through calcination. By changing the calcination conditions, the ratio of the subsequent generated filtrate and filter residue can be adjusted.

[0061] In some embodiments of the present invention, the activated product obtained by calcination is ground to a particle size ≤ 0.4 mm and then the subsequent steps are carried out. The particle size can be, for example, 0.16 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, etc., to increase the reaction area.

[0062] By activating the silicon - rich and aluminum - containing material, the present invention can fully and evenly fuse silicon and aluminum elements, promote the formation of silicon - aluminum aerogel, greatly avoid the generation of single silicon dioxide aerogel, aluminum peroxide aerogel, and aluminum hydroxide aerogel, and improve the yield and purity of the subsequent silicon - aluminum aerogel.

[0063] In the present invention, after obtaining the activated product, the activated product is mixed with water, adjusted to an acidic condition, subjected to a hydrolysis reaction, and then solid - liquid separation is carried out to obtain a filtrate and a filter residue.

[0064] It should be noted that the filtrate mainly includes meta - aluminate and meta - silicate, and the filter residue mainly includes undissolved alumina and silica as well as metal salts insoluble in acid.

[0065] In some embodiments of the present invention, the activated product is dissolved in water and then the pH value is adjusted to 1-6 with concentrated acid to promote the hydrolysis of the activated product. Among them, the mass ratio of the activated product to water is 1:1-20, for example, it can be 1:1, 1:5, 1:10, 1:15, 1:20, etc., and the concentrated acid can be, for example, concentrated hydrochloric acid, concentrated sulfuric acid or concentrated nitric acid.

[0066] In some embodiments of the present invention, the temperature of the hydrolysis reaction is 20-80 °C, for example, it can be 20 °C, 30 °C, 40 °C, 50 °C, 60 °C, 70 °C, 80 °C, etc. During the actual operation process, it can be adjusted within this range according to the actual situation, and no other special limitations are imposed.

[0067] In some embodiments of the present invention, the solid-liquid separation can be vacuum filtration. The filtrate obtained after vacuum filtration is passed through a cation exchange resin to obtain a purer filtrate, and the filtrate is a mixed solution containing metasilicic acid and metaaluminum acid.

[0068] In the present invention, after obtaining the filtrate, the filtrate is converted into silica-alumina aerogel and / or mullite whiskers.

[0069] It can be understood that after obtaining the filtrate, all the filtrate can be converted into silica-alumina aerogel, or all the filtrate can be converted into mullite whiskers, or the filtrate can be divided into two parts, one part of the filtrate is used to be converted into silica-alumina aerogel, and the other part of the filtrate is used to be converted into mullite whiskers.

[0070] In the present invention, the method for converting the filtrate into silica-alumina aerogel is as follows: the pH of the filtrate is adjusted to neutral and then second aging and third drying are carried out in sequence to obtain silica-alumina aerogel.

[0071] In some embodiments of the present invention, the pH value of the filtrate is adjusted to neutral by dropping concentrated ammonia water. By adjusting the pH value of the filtrate, hydrogen ions can be removed to promote gelation. The temperature of the second aging is 20-80 °C, for example, it can be 20 °C, 40 °C, 60 °C, 80 °C, etc., and the second aging time is 2-48 h, for example, it can be 2 h, 12 h, 24 h, 36 h, 48 h, etc. The wet silica-alumina gel can be obtained during the aging process, and the gel aging time can be controlled by changing the temperature.

[0072] In some embodiments of the present invention, a detergent is added to the silicon-aluminum wet gel and left standing for 12 - 24 h, followed by solid-liquid separation to obtain a pure silicon-aluminum wet gel. Among them, the detergent is a mixed solution of n-hexane and absolute ethanol with a mass ratio of 1:1 - 10. Through washing, impurities in the silicon-aluminum wet gel can be removed. The impurities refer to ammonium ions in the concentrated ammonia water in the previous step, acid radicals that failed to form a gel, and water. Moreover, by using n-hexane with a smaller surface tension as the detergent, the prepared silicon-aluminum aerogel can have denser and more uniform pores, improving its thermodynamic performance.

[0073] In some embodiments of the present invention, the third drying is stepwise drying, and the stepwise drying is specifically as follows: drying at a constant temperature of 20 - 60 °C for 1 - 10 h, drying at a constant temperature of 60 - 100 °C for 1 - 10 h, and drying at a constant temperature of 100 - 150 °C for 1 - 10 h. Through stepwise drying, water, ethanol and other solutions can be effectively removed in stages, making the pores of the gel more uniform, the porosity larger and less likely to collapse.

[0074] In the present invention, the method for converting the filtrate into a silicon-aluminum aerogel is as follows: the method for converting the filtrate into mullite whiskers is as follows: the filtrate is mixed with an aluminum source supplement, a sintering aid, and an acid-base regulator, followed by fourth drying and calcination to obtain mullite whiskers. Among them, the mixing can be carried out by heating and stirring in a water bath at 20 - 60 °C, and the stirring speed is 100 - 1500 r / min.

[0075] In some embodiments of the present invention, the addition amount of the aluminum source supplement is 20 - 80% of the mass of the filtrate. For example, it can be 20%, 30%, 40%, 50%, 60%, 70%, 80%, etc. The aluminum source supplement includes one or more of aluminum oxide, aluminum chloride, aluminum sulfate, and aluminum hydroxide. By adding the aluminum source supplement, the molar ratio of silicon and aluminum elements can be re-formulated.

[0076] In some embodiments of the present invention, the addition amount of the sintering aid is 3 - 25% of the mass of the filtrate. For example, it can be 3%, 5%, 10%, 15%, 20%, 25%, etc. The sintering aid includes fluorides, including one or more of aluminum fluoride, ammonium fluoride, sodium fluoride, magnesium fluoride, calcium fluoride, and cryolite. By adding the sintering aid, the calcination crystallization temperature can be reduced.

[0077] In some embodiments of the present invention, the addition amount of the acid-base regulator is 0.1-3% of the mass of the filtrate. For example, it can be 0.1%, 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, etc. The acid-base regulator is an organic acid and / or an inorganic acid, including one or more of dilute hydrochloric acid, dilute sulfuric acid, dilute nitric acid, formic acid, acetic acid, oxalic acid, tartaric acid, hypochlorous acid, carbonic acid, citric acid, malic acid, and hydrofluoric acid. The aspect ratio of the mullite whiskers can be adjusted by the acid-base regulator.

[0078] In some embodiments of the present invention, the fourth drying temperature is 60-150°C. For example, it can be 60°C, 80°C, 100°C, 120°C, 150°C, etc. For the degree of drying, it is sufficient to dry to constant weight. The specific time can be adjusted according to the actual situation. As long as the drying method can be achieved, such as blast drying, vacuum drying, etc., no special limitation is made here.

[0079] In some embodiments of the present invention, the material after the fourth drying is ground into a powder with a particle size ≤ 0.4 mm and then calcined. The particle size can be, for example, 0.04 mm, 0.08 mm, 0.12 mm, 0.16 mm, 0.20 mm, 0.25 mm, 0.30 mm, 0.35 mm, 0.40 mm, etc., to increase the specific surface area of the material and enhance the calcination activation effect.

[0080] In some embodiments of the present invention, the powder is roasted. The roasting temperature is 725-850°C. For example, it can be 725°C, 750°C, 800°C, 850°C, etc. The roasting time is 1.5-3.5 h. For example, it can be 1.5 h, 2 h, 2.5 h, 3 h, 3.5 h, etc. The roasting process can cause the material to crystallize into whiskers, and mullite whiskers are obtained after cooling.

[0081] The present invention uses the sol-gel method to prepare mullite whiskers, which can complete the synthesis of mullite whiskers at a lower temperature, while maintaining its complete crystal structure and a relatively high aspect ratio, so that the mullite whiskers have good mechanical properties and high-temperature heat insulation properties.

[0082] In the present invention, after obtaining the filter residue, the filter residue, strong base, and water are mixed, and then first aging and second drying are carried out in sequence to obtain zeolite.

[0083] In some embodiments of the present invention, the mass ratio of the filter residue to the strong base is 1:1-10. For example, it can be 1:1, 1:2, 1:4, 1:6, 1:8, 1:10, etc. The strong base includes one or several of sodium hydroxide, potassium hydroxide, sodium carbonate, potassium nitrate, sodium phosphate, potassium carbonate, potassium chloride, potassium sulfate, sodium silicate, calcium hydroxide, etc., which can effectively dissolve the filter residue to form aluminosilicate.

[0084] In some embodiments of the present invention, the mass ratio of the filter residue to water is 1:0.8 - 1.2, for example, it can be 1:0.8, 1:0.9, 1:1, 1:1.1, 1:1.2, etc.

[0085] In some embodiments of the present invention, the filter residue, strong base, and water can be mixed at room temperature or by heating. When heating is used for mixing, the speed of uniform mixing can be accelerated. The heating temperature for mixing can be 60 - 180 °C, for example, it can be 60 °C, 100 °C, 120 °C, 150 °C, 180 °C, etc. The stirring speed during mixing is 100 - 1200 r / min, for example, it can be 100 r / min, 500 r / min, 800 r / min, 1200 r / min, etc.

[0086] In some embodiments of the present invention, zeolite is prepared by the sol - gel crystallization method. The first aging temperature is 20 - 80 °C, for example, it can be 20 °C, 40 °C, 60 °C, 80 °C, etc. The first aging time is 2 - 48 h, for example, it can be 2 h, 12 h, 24 h, 36 h, 48 h, etc. A wet gel can be obtained during the aging process. By changing the temperature, the gel aging time can be controlled; the pH value of the material after the second aging is adjusted to 7 - 8 to promote crystallization.

[0087] In some embodiments of the present invention, the temperature of the second drying is 60 - 180 °C, for example, it can be 60 °C, 90 °C, 120 °C, 150 °C, 180 °C, etc. Drying can promote an increase in the porosity of the zeolite and improve the active area of the zeolite. For the degree of drying, it is sufficient to dry to a constant weight. The specific time can be adjusted according to the actual situation. As long as the drying method can be achieved, such as blast drying, vacuum drying, etc., no special limitation is made here.

[0088] The zeolite prepared by the sol - gel crystallization method in the present invention has large and uniform porosity and a high yield, and has broad application potential in the fields of catalysis, adsorption, and separation.

[0089] In another aspect of the present invention, a material prepared by the reuse method of the silicon - rich aluminous material described in any one of the above is provided. The material includes zeolite, silica aerogel, and / or mullite whiskers. Since the zeolite, silica aerogel, and / or mullite whiskers are prepared by the above - mentioned method, the material has all the characteristics described above and will not be elaborated here.

[0090] Hereinafter, the technical solutions in the present invention will be clearly and completely described in conjunction with specific embodiments. The embodiments of this application are only for illustration. All other embodiments obtained by those skilled in the art without creative efforts fall within the protection scope of the present invention.

[0091] Example 1

[0092] This embodiment provides a method for recycling silicon-rich aluminum-containing materials, and the specific steps are as follows:

[0093] (1) Silicon aluminum ore, sodium hydroxide and deionized water were mixed in a mass ratio of 1:1.2:5, and magnetically stirred at 30°C and 100 r / min until uniform, and then vacuum dried at 60°C to obtain a solid, and the solid was ground to obtain a powder with a particle size of ≤0.4 mm, and the powder was filled into a crucible and calcined at 700°C for 2h to obtain an activated product; wherein the raw material composition of the silicon aluminum ore is shown in Table 1:

[0094] Table 1

[0095] Raw material components <![CDATA[SiO 2 > <![CDATA[Al 2 O 3 > <![CDATA[TiO 2 > CaO <![CDATA[Fe 2 O 3 > <![CDATA[K 2 O]]> Other trace oxides Content (%) 42.25 46.61 1.96 3.57 1.56 1.54 2.51

[0096] (2) grinding the activated product to a particle size of ≤0.4 mm, mixing it with deionized water at a mass ratio of 1:1, adding concentrated hydrochloric acid to adjust the pH value of the resulting mixture to 4, performing a hydrolysis reaction, and then performing vacuum filtration to obtain a filtrate and a filter residue;

[0097] (3) passing the filtrate through a cation exchange resin to obtain a pure mixed solution containing metasilicic acid and metaaluminic acid, and dividing the mixed solution into two parts;

[0098] (4) Add concentrated ammonia to one of the mixed solutions to adjust the pH to 7, place it at 20°C for aging for 48 hours, then add a mixed solution of n-hexane and anhydrous ethanol in a volume ratio of 1:1 and let it stand for 24 hours, filter it to obtain a silicon-alumina wet gel, and perform step drying on the silicon-alumina wet gel, specifically drying it at 30°C, 80°C, and 130°C for 3 hours, respectively, to obtain a block of silicon-alumina aerogel;

[0099] (5) adding aluminum hydroxide (the amount added is 50% of the mass of the mixed solution) and aluminum fluoride (the amount added is 17% of the mass of the mixed solution) to another mixed solution, heating and stirring in a water bath at 30° C., and a stirring speed of 100 r / min, continuing to add acetic acid (the amount added is 3% of the mass of the mixed solution) for adjustment, and then vacuum drying at 60° C. to obtain a solid, grinding the solid to obtain a powder with a particle size of ≤0.4 mm, calcining the powder at 725° C. for 3 h, and cooling to obtain mullite whiskers;

[0100] (6) The filter residue and sodium hydroxide were mixed in a mass ratio of 1:1, heated and stirred at 60°C and 100 r / min, and after mixing evenly, the mixture was placed at 60°C for aging for 48 hours, and then deionized water was added to adjust the pH to 7, and vacuum dried at 60°C to obtain block zeolite.

[0101] Example 2

[0102] This embodiment provides a method for recycling silicon-rich aluminum-containing materials, and the specific steps are as follows:

[0103] (1) Silica-alumina colloid residue, sodium bicarbonate and deionized water were mixed in a mass ratio of 1:0.8:5, and magnetically stirred at 30°C and 100 r / min until uniform, and then vacuum dried at 80°C to obtain a solid, and the solid was ground to obtain a powder with a particle size of ≤0.4 mm, and the powder was filled into a crucible and calcined at 850°C for 2.5 h to obtain an activated product; wherein the raw material composition of the silica-alumina colloid residue is shown in Table 2:

[0104] Table 2

[0105] Raw material <![CDATA[SiO 2 > <![CDATA[Al 2 O 3 > MgO CaO <![CDATA[Fe 2 O 3 > <![CDATA[K 2 O]]> <![CDATA[Sodium 2 O]]> Other oxides Content 43.31 41.86 0.84 3.77 1.67 1.27 0.85 6.43

[0106] (2) grinding the activated product to a particle size of ≤0.4 mm, mixing it with deionized water at a mass ratio of 1:10, adding concentrated hydrochloric acid to adjust the pH value of the resulting mixed solution to 3, and then vacuum filtering to obtain a filtrate and a filter residue;

[0107] (3) passing the filtrate through a cation exchange resin to obtain a relatively pure mixed solution containing metasilicic acid and metaaluminic acid, and dividing the mixed solution into two parts;

[0108] (4) Add concentrated ammonia to one of the mixed solutions to adjust the pH to 7, place it at 40°C for aging for 48 hours, then add a mixed solution of n-hexane and anhydrous ethanol in a volume ratio of 1:5 and let it stand for 24 hours, filter it to obtain a silicon-alumina wet gel, and perform step drying on the silicon-alumina wet gel, specifically drying it at 40°C, 80°C, and 120°C for 3 hours, respectively, to obtain a block of silicon-alumina aerogel;

[0109] (5) adding aluminum hydroxide (the amount added is 50% of the mass of the mixed solution) and aluminum fluoride (the amount added is 17% of the mass of the mixed solution) to another mixed solution, heating and stirring in a water bath at 40° C., and the stirring speed is 150 r / min, and acetic acid (the amount added is 0.1% of the mass of the mixed solution) is continued to be added for adjustment, and then vacuum drying is performed at 60° C. to obtain a solid, and the solid is ground to obtain a powder with a particle size of ≤0.4 mm, and the powder is calcined at 825° C. for 3 h, and cooled to obtain mullite whiskers;

[0110] (6) The filter residue was mixed with sodium hydroxide in a mass ratio of 1:5, heated and stirred at 100° C. and 100 r / min, and after mixing evenly, the mixture was placed at 50° C. for aging for 48 h, and then deionized water was added to adjust the pH to 7, and vacuum dried at 80° C. to obtain a block of zeolite.

[0111] Example 3

[0112] This embodiment provides a method for recycling silicon-rich aluminous materials, and the specific steps are as follows:

[0113] (1) Mix gangue, sodium carbonate and deionized water in a mass ratio of 1:1:5, magnetically stir until uniform at 30 °C and 100 r / min, then perform vacuum drying at 80 °C to obtain a solid, grind the solid to obtain a powder with a particle size ≤ 0.4 mm, fill the powder into a crucible and calcine at 825 °C for 2.5 h to obtain an activated product; the raw material composition of the gangue is shown in Table 3:

[0114] Table 3

[0115] Raw material components <![CDATA[SiO 2 > <![CDATA[Al 2 O 3 > MgO CaO <![CDATA[Fe 2 O 3 > Other oxides Content (%) 44.31 39.86 0.96 3.17 1.56 10.14

[0116] (2) Grind the activated product to a particle size ≤ 0.4 mm and then mix it with deionized water in a mass ratio of 1:10, add concentrated hydrochloric acid to adjust the pH value of the obtained mixed solution to 3, and then perform vacuum filtration to obtain a filtrate and a filter residue;

[0117] (3) Pass the filtrate through a cation exchange resin to obtain a relatively pure mixed solution containing metasilicic acid and metaaluminic acid, and divide the mixed solution into two parts;

[0118] (4) Dropwise add concentrated ammonia water to one part of the mixed solution to adjust the pH to 7, place it in an environment of 50 °C for aging for 24 h, then add a mixed solution of n-hexane and absolute ethanol with a volume ratio of 1:10 and let it stand for 24 h, filter to obtain a silicon-aluminum wet gel, and perform stepwise drying on the silicon-aluminum wet gel, specifically drying at 60 °C, 100 °C, and 150 °C for 3 h respectively to obtain a blocky silicon-aluminum aerogel;

[0119] (5) Add aluminum hydroxide (the addition amount is 50% of the mass of the mixed solution) and aluminum fluoride (the addition amount is 17% of the mass of the mixed solution) to the other part of the mixed solution, heat and stir under a water bath condition of 40 °C, the stirring speed is 150 r / min, continue to add acetic acid (the addition amount is 0.1% of the mass of the mixed solution) for adjustment, and then perform vacuum drying at 60 °C to obtain a solid, grind the solid to obtain a powder with a particle size ≤ 0.4 mm, and calcine the powder at 825 °C for 3 h, cool to obtain mullite whiskers;

[0120] (6) Mix the filter residue and sodium hydroxide in a mass ratio of 1:5, heat and stir at 100 °C and 100 r / min, after mixing evenly, place it in an environment of 50 °C for aging for 48 h, then add deionized water to adjust the pH to 7, and perform vacuum drying at 80 °C to obtain a blocky zeolite.

[0121] Example 4

[0122] This example is basically the same as Example 3, except that: the calcination temperature in step (1) is 750 °C.

[0123] Example 5

[0124] This example is basically the same as Example 3, except that: the calcination time in step (1) is 1.5 h.

[0125] The mass percentages of the filtrate and filter residue in Examples 1 - 5 were statistically analyzed, and the results are shown in Table 4:

[0126] Table 4

[0127] Mass percentage % Example 1 Example 2 Example 3 Example 4 Example 5 Filtered liquid 71.2 74.3 69.4 46.7 58.6 Filter residue 28.8 25.7 30.6 53.3 41.4

[0128] As can be seen from Table 4, during the preparation of the activated product, by adjusting the calcination temperature, the generation ratios of the filtrate and filter residue can be adjusted. Specifically, by reducing the calcination temperature, the proportion of the filter residue can be relatively increased, and by reducing the calcination time, the proportion of the filtrate can be relatively increased.

[0129] Comparative Example 1

[0130] This comparative example provides a conventional preparation method for silica - alumina aerogel, and the specific steps are as follows:

[0131] (1) Mix the silicon source, deionized water, ethanol, and formamide in a mass ratio of 15:10:8:2, adjust the pH value to 4 at room temperature for catalytic hydrolysis reaction, and then adjust the ambient temperature to 30 °C to gel the solution to obtain an initial gel;

[0132] (2) Immerse the initial gel in absolute ethanol and seal it for 24 h, pour out the absolute ethanol, add a mixed solution of tetraethoxysilane and ethanol with a volume ratio of 15:8, and continue to immerse it for 24 h to obtain an aged gel;

[0133] (3) Separate the mixed solution of tetraethoxysilane and ethanol, rinse the aged gel with n - hexane with a smaller surface tension at a mass ratio of 1:1 for 24 h to reduce gel cracking, and dry it at 100 °C for 24 h to obtain silica - alumina aerogel.

[0134] Comparative Example 2

[0135] This comparative example provides a conventional preparation method for mullite whiskers, and the specific steps are as follows:

[0136] Mix the powdered alumina, silica, and aluminum fluoride evenly in a mass ratio of 2:3:1, load them into a crucible, calcine at 1300 °C for 6 h, and cool to obtain mullite whiskers.

[0137] Comparative Example 3

[0138] This comparative example provides a conventional preparation method for zeolite, and the specific steps are as follows:

[0139] (1) Kaolin and sodium hydroxide are mixed at a mass ratio of 1:5, and then sodium aluminate is added to obtain a mixed solution;

[0140] (2) The mixed solution is aged at room temperature for 48 h and then heated to 180 °C for crystallization treatment. After washing with deionized water and filtering, it is dried at 120 °C for 12 h to obtain zeolite.

[0141] Comparative Example 4

[0142] This comparative example is basically the same as Example 1, and the only difference is that: in step (4), the silicon-aluminum wet gel is dried at 100 °C for 3 h.

[0143] Performance tests were carried out on the products of Examples 1-3 and Comparative Examples 1-4, and the test results are shown in Table 5.

[0144] Table 5

[0145]

[0146]

[0147] As can be seen from Table 5, compared with the aerogel prepared by the traditional method, the aerogel obtained by recycling the silicon-rich aluminum-containing material in the present invention has a larger relative specific surface area and porosity, as well as a lower thermal conductivity and density, and can exhibit better heat insulation performance.

[0148] Compared with the mullite whiskers prepared by the traditional method, the mullite whiskers obtained by recycling the silicon-rich aluminum-containing material in the present invention have a lower thermal conductivity, a higher aspect ratio and purity, and other properties are comparable, and have good heat insulation performance.

[0149] Compared with the zeolite prepared by the traditional method, the zeolite obtained by recycling the silicon-rich aluminum-containing material in the present invention has better copper ion adsorption performance.

[0150] In the process of preparing silicon-aluminum aerogel, if the gradient drying process is replaced by conventional drying, the specific surface area and porosity of the silicon-aluminum aerogel will both decrease, while the thermal conductivity and density increase, that is, the heat insulation performance will deteriorate.

[0151] The utilization rate of the silicon-rich aluminum-containing material by the method of the present invention can reach more than 98%, effectively solving the impact of the accumulation of the silicon-rich aluminum-containing material on the environment, and the aerogel, mullite whiskers and zeolite obtained from the silicon-rich aluminum-containing material as raw materials all have good properties, effectively improving the use value of the silicon-rich aluminum-containing material.

[0152] Although the embodiments of the present invention have been shown and described above, it can be understood that the above embodiments are exemplary and should not be construed as limiting the present invention. Those of ordinary skill in the art can make changes, modifications, substitutions, and variations to the above embodiments within the scope of the present invention.

Claims

1. A method for recycling silicon-rich aluminum-containing materials, characterized in that: The following steps are involved: (1) mixing a silicon-rich aluminum-containing material, an activating agent and water, and then sequentially performing a first drying and calcining to obtain an activated product; (2) mixing the activated product with water, adjusting the mixture to an acidic state, performing a hydrolysis reaction, and then performing solid-liquid separation to obtain a filtrate and a filter residue; (3) converting the filtrate into silica-alumina aerogel and / or mullite whiskers; (4) The filter residue, strong alkali and water are mixed, and then a first aging and a second drying are performed in sequence to obtain zeolite.

2. The method for recycling silicon-rich aluminum-containing materials according to claim 1, characterized in that: The mass ratio of the silicon-rich aluminum-containing material, the active agent and water in step (1) is 1:(0.5-1.2):5; The active agent includes one or more of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium nitrate, potassium hydroxide, potassium carbonate, potassium bicarbonate, potassium nitrate, magnesium hydroxide, magnesium carbonate, magnesium nitrate, calcium hydroxide, calcium carbonate, calcium bicarbonate, and calcium nitrate. The first drying temperature is 60-150°C; The calcination temperature is 700-900°C and the calcination time is 1-5h; Before the calcination in step (1), the following step is also included: grinding the first dried material to a particle size of ≤0.4 mm.

3. The method for recycling silicon-rich aluminum-containing materials according to claim 1, characterized in that: The temperature of the hydrolysis reaction in step (2) is 20-80°C.

4. The method for recycling silicon-rich aluminum-containing materials according to claim 1, characterized in that: In step (4), the mass ratio of the filter residue to the strong base is 1:1-10, and the mass ratio of the filter residue to water is 1:0.8-1.2; The mixing is heating mixing, and the mixing is heating mixing, and the temperature of the heating mixing is 60-180°C; The first aging temperature is 20-80° C., and the first aging time is 2-48 hours; The second drying temperature is 60-180°C; Before the second drying in step (4), the method further includes the following steps: adjusting the pH value of the aged material to 7-8.

5. The method for recycling silicon-rich aluminum-containing materials according to claim 1, characterized in that: The method for converting the filtrate into silica-alumina aerogel in step (3) is as follows: the pH of the filtrate is adjusted to neutral, and then a second aging and a third drying are performed in sequence to obtain silica-alumina aerogel.

6. The method for recycling silicon-rich aluminum-containing materials according to claim 5, characterized in that: The second aging temperature is 20-80°C, and the second aging time is 2-48h; The third drying is step drying, and the step drying is specifically: constant temperature drying at 20-60°C for 1-10h, constant temperature drying at 60-100°C for 1-10h, and constant temperature drying at 100-150°C for 1-10h.

7. The method for recycling silicon-rich aluminum-containing materials according to claim 1, characterized in that: The method for converting the filtrate into mullite whiskers in step (3) is as follows: the filtrate is mixed with an aluminum source supplement, a sintering aid, and an acid-base regulator, and then subjected to a fourth drying and roasting in sequence to obtain mullite whiskers.

8. The method for recycling silicon-rich aluminum-containing materials according to claim 7, characterized in that: The amount of the aluminum source supplement added is 20-80% of the mass of the filtrate; The amount of the sintering aid added is 3-25% of the mass of the filtrate; The amount of the acid-base regulator added is 0.1-3% of the mass of the filtrate; The temperature of the fourth drying is 60-150°C; The calcination temperature is 725-850°C and the calcination time is 1.5-3.5h; The method also includes the following steps before roasting: grinding the material after the fourth drying to a particle size of ≤0.4 mm.

9. The method for recycling silicon-rich aluminum-containing materials according to any one of claims 1 to 8, characterized in that: Before converting the filtrate into silica-alumina aerogel and / or mullite whisker, the method further comprises filtering the filtrate through a cation exchange resin.

10. A material prepared by the method for recycling silicon-rich aluminum-containing materials according to any one of claims 1 to 9, characterized in that: The materials include zeolites, silica-alumina aerogels and / or mullite whiskers.

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