Method for synthesizing carbon hybrid multi-metal center mesoporous materials using coal gangue

Abstract

The present invention relates to the technical field of coal gangue utilization, and provides a method for synthesizing a carbon hybrid multi-metal center mesoporous material using coal gangue, comprising: (1) adding coal gangue to a solution containing potassium permanganate, hydrochloric acid, and phosphoric acid, and magnetically stirring to obtain a suspension; adding hydrogen peroxide to the solution before the end of the suspension treatment time; (2) adding a soluble silicate and / or a soluble silicic acid to the obtained suspension to obtain a suspension A; (3) adding a solution B containing an alkaline metal compound and a metal salt to the suspension A, and magnetically stirring to obtain a precursor solution; (4) transferring the obtained precursor solution into a closed reactor, applying a magnetic field to react to obtain a mixed product containing solid and liquid; (5) separating the obtained mixed product into a solid-liquid separation to obtain a solid carbon hybrid multi-metal center mesoporous material. The carbon hybrid multi-metal center is uniformly dispersed, analcime and the like are generated in the mesoporous material, which is conducive to adsorption crystal form, and the mesopores are stable.

Description

Technical Field

[0001] The present application relates to the technical field of coal gangue utilization, and in particular to a method for synthesizing carbon hybrid multi-metal center mesoporous materials by utilizing coal gangue. Background Art

[0002] After coal is mined and washed through multiple stages, it produces large amounts of solid waste, including gangue. Gangue is a dark gray rock with a low carbon content (10%-30%) and is harder than coal. It typically accounts for about 10-20% of coal production.

[0003] Gangue is primarily composed of kaolinite, quartz, calcite, pyrite, and illite, with a certain amount of organic matter and a small amount of mica. Its main elements include Si, Al, C, Ca, Fe, Mg, and K. Over the past few decades, extensive research has focused on the utilization of gangue, primarily focusing on landfill, building materials production, energy industry, and agriculture. Despite this, achieving high-value utilization of gangue remains a challenge.

[0004] Mineral composition analysis indicates that the composition of coal gangue varies with geographic location, but most gangue is primarily composed of kaolinite (Al₂O₃·2SiO₂·2H₂O), a hydrous aluminosilicate clay mineral. SiO₂ and Al₂O₃ typically account for over 80% of the total composition. Clay minerals such as kaolinite are nano-layered silicates composed of 1:1 or 1:2 silicon-oxygen tetrahedra and metal-oxygen octahedra. These tetrahedra and metal-oxygen octahedra are connected by Si-O-Si and Si-OM (M: Al, Fe, Mg) bonds, forming a nanosheet structure. For example, Chinese patent CN115196640A discloses a mesoporous silica material based on coal gangue and its preparation method, wherein a coal gangue-based silicon source, an organic carboxylic acid, anhydrous organic alcohol and a surfactant are mixed and reacted, and a mesoporous material is prepared through a series of steps including self-assembly treatment, centrifugation, drying, activation with an inorganic strong acid solution, and roasting. However, this method uses the silicon species extract obtained after the solid waste coal gangue is sequentially subjected to acid washing and dealuminization treatment under stirring and reflux, activation treatment with an inorganic strong alkali solution under high temperature and high pressure super(sub)critical conditions and dissolution treatment with an inorganic strong acid solution as the silicon source, that is, the coal gangue needs to be treated with acid washing, alkali treatment and other processes before being used as a raw material with the help of organic The selective and appropriate introduction of alcohols and organic carboxylic acids, combined with solvent thermal self-assembly, regulates the hydrolysis-polymerization degree of silicon species and the surface hydroxyl content, promoting their synergistic self-assembly with block copolymer non-ionic surfactants, and with the help of high-temperature hydrothermal polymerization treatment in a strong acid solution at a pH value close to the isoelectric point of silica, a mesoporous silica material with a highly uniform mesoporous channel structure and high hydrothermal stability is prepared; repeated modification with strong acids, strong bases and other additives is complex, the cross-use of acids and bases leads to a significant increase in usage, and it is only utilized from the perspective of raw material composition, and fails to be utilized from the perspective of coal gangue composition such as carbon-containing substances, layered crystal structure, etc.

[0005] Chinese patent CN115057458A discloses a method for preparing nano-alumina from coal gangue. Gangue loaded with an inorganic salt of alkali metal K, an inorganic salt of Na, or biomass is gasified or burned at high temperature to activate the gangue at high temperature. The resulting aluminum hydroxide precursor is then calcined, washed, acid-washed, and filtered to produce flaky alumina. The gasification or combustion temperature is 600-1000°C, and alkali metals are used as activators. Using an inorganic salt or biomass containing alkali metals as an activator can improve aluminum extraction efficiency and effectively reduce the thermal activation temperature. Based on the characteristics of the solution after acid dissolution, combined with the traditional molten salt method (MSS) for preparing flaky alumina, a mixed solution of KOH and NaOH is added to the acidic crude solution to adjust the pH and form molten salts K2SO4 and Na2SO4. The molten salts can be recovered and reused as an activator for coal gangue. Gangue loaded with inorganic salts of alkali metals K, Na, or biomass is gasified or burned at high temperatures to activate the gangue, a process that also consumes carbon in the gangue. However, this method primarily consumes carbon in the gangue through combustion, with the carbon used solely for combustion. Flake alumina, obtained through acid leaching and alkali solution, has low utilization rates of the gangue components, effectively utilizing only one component, alumina, and requires complex processes such as impurity removal.

[0006] A Chinese patent discloses a method for fully reacting sulfuric acid with carbonate impurities in coal gangue; the resulting powder is ground with a stone mill and then calcined at 200-600°C for 1-6 hours to produce activated coal gangue powder. The activated coal gangue powder is then dispersed in a soluble silicate aqueous solution, followed by the addition of magnesium salts and nitrilotriacetic acid. The addition of nitrilotriacetic acid promotes the mineral transformation and reconstructing into analcime with a flower-like morphology. A hydrothermal reaction yields a pure-phase analcime product with a flower-like morphology. However, this method involves reacting the acid with the components of the coal gangue before calcination, and organic carbon and other substances in the gangue significantly interfere with the reaction. Furthermore, the use of specialized acids such as nitrilotriacetic acid to convert the crystals increases costs, making large-scale application impractical. Furthermore, the use of nitrilotriacetic acid has limited effects on the zeolite structure.

[0007] Chinese patent CN110921677A discloses a method for preparing 4A zeolite from kaolin. The method involves calcining kaolin at low temperature and then aging the alkali-melted activated product in an external magnetic field. The magnetic field increases the number of 4A zeolite nuclei and reduces the size of crystal aggregation, thereby increasing the volume and stability of the colloid formed. This improves the quantity and quality of the 4A zeolite synthesized after crystallization, reduces the particle size, and improves the quality of the 4A zeolite. Crystallization is carried out in a non-magnetic field. Without an external magnetic field, water molecules are demagnetized, which can reduce solubility and form a supersaturated solution. The supersaturated solute precipitates in large quantities, forming a large number of small-sized crystal nuclei. Crystallization is carried out on these small nuclei, reducing the particle size of the 4A zeolite, increasing the calcium exchange capacity and whiteness, and improving the yield and quality of the 4A zeolite. This method involves mixing saturated sodium hydroxide aqueous solution with kaolin and then calcining it. This requires a large amount of soda ash, and a magnetic field is used to increase dissolution. Subsequently, crystallization occurs slowly without an external magnetic field, making it difficult to more effectively promote the crystallization transformation of the zeolite and further improve the adsorption efficiency. In addition, this method fails to effectively utilize components such as carbon in coal gangue, and carbon is lost during combustion during the soda ash calcination process, making it difficult to exert the role of the carbon component.

[0008] In addition, in the existing technology, in the process of utilizing coal gangue, soluble silicates are added to supplement metal salts to prepare mesoporous materials. In order to facilitate the dispersion and reasonable distribution of metal salts, it is necessary to add template agents, surfactants and other substances to improve the adsorption performance. However, the addition of template agents and surfactants undoubtedly increases the cost and increases the complexity of the process.

[0009] As can be seen from the above, the preparation process using existing methods is relatively complex, requiring extensive use of acid-base combinations, the addition of additives for pore formation, the addition of templates, surfactants, and other substances. The use of a single component of coal gangue further complicates the process, and impurity removal issues further complicate the process, making it difficult to effectively utilize components such as carbon in the gangue. Therefore, the present invention provides a new method for synthesizing carbon-hybrid multi-metal mesoporous materials using coal gangue. This technology is currently lacking in the literature and has no precedent for its application. Summary of the Invention

[0010] To overcome the shortcomings of the prior art, the present application provides a method for synthesizing carbon-hybridized multi-metal center mesoporous materials using coal gangue, which achieves the acquisition of carbon-hybridized multi-metal center mesoporous materials without the need for concentrated alkali, template agents, surfactants, chelating agents and other external additives, and under low acid conditions. The carbon-hybridized multi-metal center is evenly dispersed, and the generation of analcime and the like in the mesoporous material is conducive to the adsorption of crystal forms. The mesopores are stable, and organic dyes, heavy metals, antibiotics, phosphorus and other pollutants can be efficiently removed. The mineral components in the coal gangue are converted into multi-metal-carbon composite materials, and metal elements, carbon and other components are effectively utilized, thereby largely avoiding the waste of valuable metals and carbon, and being suitable for industrial production.

[0011] The embodiment of the present application is implemented as follows:

[0012] This application example provides a method for synthesizing carbon hybrid multi-metal center mesoporous materials using coal gangue, comprising:

[0013] (1) Grind the coal gangue into powder (10-60 g), add it to a solution containing 0.09-0.15 mol / L potassium permanganate, 2-5 mol / L hydrochloric acid, and 0.5-1 mol / L phosphoric acid; disperse it in deionized water under the action of magnetic stirring at a solid-liquid ratio of 10:1-100:1 (g / L) to obtain a uniform suspension; the treatment temperature is 45-73°C, and the treatment time is 30-130 min; 5-10 min before the end of the suspension treatment time, add 0.01-0.02 mol / L hydrogen peroxide to the solution;

[0014] (2) Add soluble silicate and / or soluble silicic acid to the suspension obtained above, stir thoroughly, and then ultrasonicate with a cell crusher for 1-10 minutes, and continue magnetic stirring to obtain a uniform suspension A;

[0015] (3) Add the alkaline metal compound and the metal salt to 30-100 ml of deionized water and stir magnetically to dissolve the metal compound and the metal salt to obtain a clear solution B; slowly add the solution B containing the alkaline metal compound and the metal salt to the suspension A and continue stirring magnetically for 10-60 minutes to obtain a uniform precursor solution;

[0016] The magnetic field strength during the magnetic stirring process is 0.15-0.3T;

[0017] (4) The precursor solution obtained above is transferred into a closed reactor, and a magnetic field is applied to react for 2-36 hours at a temperature of 60-300°C and a pressure of 1-20 MPa to obtain a mixed product containing solid and liquid. The magnetic field strength is 0.45-0.65 T.

[0018] (5) The mixed product obtained above is subjected to solid-liquid separation to obtain a solid carbon hybrid multi-metal central mesoporous material.

[0019] Optionally, in step (1), the gangue is crushed into powder and then calcined at 125-160° C. During the calcination process, a 0.7-1.1 wt % potassium permanganate aqueous solution is sprayed through a nozzle, the sprayed mass accounts for 0.05-0.08 wt % of the mass of the gangue, and the spraying time is 0.5-1 h.

[0020] Optionally, the soluble silicate in step (2) is one or any combination of lithium silicate, sodium silicate, ammonium silicate, and potassium silicate, the soluble silicic acid is orthosilicic acid, and the amount of soluble silicate and / or soluble silicic acid added is 10-50% of the total mass of the suspension.

[0021] Optionally, the soluble silicates in step (2) are lithium silicate, sodium silicate and potassium silicate, and based on the total mass of the soluble silicates, the ratio of lithium silicate: sodium silicate: potassium silicate is (1.5-1.7): (14-15): (17-18).

[0022] Optionally, the metal salt in step (3) is one or any combination of magnesium carbonate, magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium trisilicate, zinc chloride, zinc sulfate, zinc nitrate, zinc dihydrogen phosphate, calcium halide, calcium carbonate, calcium nitrate, calcium chlorate, calcium perchlorate, calcium bicarbonate, and calcium dihydrogen phosphate, and the added amount is 5-50% of the mass of the soluble silicate and / or soluble silicic acid.

[0023] Optionally, the metal salt in step (3) is one of magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, and magnesium trisilicate, accounting for 55-85% of the total mass of the metal salt.

[0024] Optionally, the alkaline metal compound in step (3) is one or any combination of magnesium hydroxide, magnesium oxide, basic magnesium carbonate, zinc oxide, zinc hydroxide, calcium oxide, calcium hydroxide, and dolomite, and the added amount is 10-60% of the mass of the soluble silicate and / or soluble silicic acid.

[0025] Optionally, the powder particle size of the coal gangue after crushing in step (1) is 62-100 μm.

[0026] Optionally, the treatment temperature in step (1) is 45-53°C.

[0027] Optionally, the amount of soluble silicate and / or soluble silicic acid added in step (2) is 33-41% of the total mass of the suspension.

[0028] Beneficial effects include:

[0029] The present invention provides a method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue, wherein hydrochloric acid is used to dissolve part of the Al in the coal gangue to increase the porosity and form a Si-C skeleton; phosphoric acid is added because it can passivate part of the active sites and inhibit Fe 3+Metal impurities such as KMnO4 catalyze the deep oxidation of carbon, reduce the breakage of carbon structure, inhibit the excessive oxidation of Si-C skeleton by potassium permanganate, and reduce the carbon loss rate; in sulfuric acid-phosphoric acid mixed acid, KMnO4 shows strong oxidizing ability, which is beneficial to the oxidation of active sites of carbon components in coal gangue (such as edge carbon, defect sites), etc., and carbon is partially oxidized into oxygen-containing functional groups such as carboxyl and carbonyl. The increased oxygen-containing groups are conducive to the adsorption of metal ions and become subsequent nucleation sites, providing conditions for transformation, growth, and nucleation for the formation of carbon hybrid metal polymetallic centers; the generation of more nucleation sites utilizes the carbon component in coal gangue, which can avoid agglomeration during metal loading, and at the same time greatly reduces the demand for templates (especially alkyl imidazole organic templates) and organic surfactants during metal hybridization, thereby eliminating the above-mentioned ingredients, reducing process complexity, reducing costs, and avoiding the risk of deterioration caused by the addition of inappropriate amounts of templates, surfactants and other ingredients. At the same time, KMnO4 shows strong oxidizing ability, which is conducive to the partial graphitization of carbon components in coal gangue under the condition of strengthening, increasing porosity and achieving a stable mesoporous structure. By adding appropriate proportions and rationally controlling oxidizing properties, some of them have a tendency to graphene, that is, the carbon components are layered and flattened, which is conducive to increasing nucleation sites and the formation of carbon hybrid metal polymetallic centers, thereby increasing adsorption performance. After adding hydrogen peroxide (H2O2), it reacts with residual potassium permanganate to generate soluble Mn 2+ Ions can terminate the oxidation reaction, moderately control the oxidation intensity, block further carbon reactions, and prevent excessive carbon oxidation loss, thereby stabilizing graphene-prone carbon. They also increase the number of hydroxyl groups, which increases metal ion loading sites, fostering a greater number of nucleation sites and promoting the formation of carbon-hybrid metal polymetallic centers, thereby enhancing adsorption performance. A high magnetic field intensity is used during the stirring process, which solubilizes and promotes the uniform dispersion of metal ions. A hydrothermal reaction forms a solid carbon-hybrid polymetallic center mesoporous material in the solution. The oxygen-containing groups generated earlier, the Si-O, Si-OC, and Si-OC-Al frameworks formed by reaction with soluble silicates, and the numerous nucleation sites provide extremely favorable conditions for the adsorption, nucleation, and crystallization of metal ions in the solution. The application of a high-intensity magnetic field not only solubilizes but also promotes the uniform dispersion and diffusion of metal ions, facilitating the formation of numerous small nuclei. Crystallization occurs on these small nuclei, further promoting the crystallization process and favoring the formation of crystalline structures such as analcime, thereby enhancing catalytic performance. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following is a brief introduction to the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present application and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without creative work.

[0031] Figure 1 SEM image of the carbon hybrid multi-metal center mesoporous material of Example 1;

[0032] Figure 2 N2 adsorption-desorption isotherms of the carbon hybrid multi-metallic center mesoporous material of Example 1;

[0033] Figure 3 Pore ​​size distribution curve of the carbon hybrid multi-metal central mesoporous material of Example 1;

[0034] Figure 4 XRD curve of the carbon hybrid multi-metal center mesoporous material of Example 1.

[0035] Explanation of the attached table:

[0036] Table 1 shows the pore structure parameters of carbon hybrid multi-metal center mesoporous materials;

[0037] Table 2 shows the saturated adsorption capacity of carbon hybrid multi-metal center mesoporous materials for phosphate, tetracycline, Cd(II) and Pb(II). DETAILED DESCRIPTION

[0038] The following will clearly and completely describe the technical solutions of the present invention in conjunction with the embodiments. 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 creative efforts are within the scope of protection of the present invention.

[0039] Those skilled in the art will understand that, unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by those skilled in the art in the art to which this invention belongs. It should also be understood that terms such as those defined in common dictionaries should be understood to have meanings consistent with their meanings in the context of the prior art and, unless specifically defined as such, will not be interpreted in an idealized or overly formal sense.

[0040] Those skilled in the art will understand that, unless otherwise stated, the singular forms "a", "an", "said" and "the" used herein may also include plural forms. It should be further understood that the term "comprising" used in the specification of the present invention refers to the presence of the features, integers, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components and / or groups thereof. The term "and / or" used herein includes all or any unit and all combinations of one or more associated listed items. The raw materials used below, unless otherwise specified, are all from commercially available products. For performance testing, please refer to national standards or industry standards.

[0041] Existing methods are complex in preparation, requiring extensive use of acid-base combinations, the addition of additives for pore formation, the addition of templates and surfactants, and the use of a single gangue component. This process is further complicated by impurity removal, and the difficulty in effectively utilizing components such as carbon in gangue. Therefore, embodiments of the present invention provide a method for synthesizing carbon-hybridized multi-metallic mesoporous materials using gangue.

[0042] The features and performance of the present invention are further described in detail below with reference to the embodiments:

[0043] An embodiment of the present invention provides a method for synthesizing a carbon-hybridized multi-metal central mesoporous material using coal gangue, comprising:

[0044] (1) Grind the gangue into powder 10-60g, add it to a mixture containing 0.09-0.15mol / L of potassium permanganate (optional: 0.09mol / L, 0.1mol / L, 0.11mol / L, 0.12mol / L, 0.13mol / L, 0.14mol / L, 0.15mol / L, etc.), 2-5mol / L of hydrochloric acid (optional: 2mol / L, 2.3mol / L, 2.6mol / L, 2.7mol / L, 2.8mol / L, 3.3mol / L, 3.5mol / L) , 3.6mol / L, 3.8mol / L, 3.9mol / L, 4.1mol / L, 4.4mol / L, 4.6mol / L, 4.7mol / L, 4.8mol / L, 4.9mol / L, 5mol / L, etc.), phosphoric acid 0.5-1mol / L (optional is 0.5mol / L, 0.6mol / L, 0.7mol / L, 0.8mol / L, 0.9mol / L, 1.0mol / L, etc.) solution for 30-130min; at a solid-liquid ratio of 10:1-100:1 (g / L) (10:1g / L, 13:1g / L, 17:1g / L, 22:1g / L, 25:1g / L, 29:1g / L, 33:1g / L, 36:1g / L, 39:1g / L, 42:1g / L, 45:1g / L, 47:1g / L, 56:1g / L, 59:1g / L, 63:1g / L, 68:1g / L, 72:1g / L, 77:1g / L, 88: 1g / L, 91:1g / L, 93:1g / L, 97:1g / L, 100:1g / L, etc.) are dispersed in deionized water under the action of magnetic stirring to obtain a uniform suspension; the processing temperature is 45-73°C, preferably 45-53°C (optionally 45°C, 47°C, 48°C, 49°C, 52°C, 54°C, 55°C, 58°C, 61°C, 64°C, 66°C, 68°C, 71°C, 72°C, 73°C, etc.).

[0045] Hydrochloric acid is used to dissolve part of the Al in the coal gangue, increase the porosity, and form a Si-C skeleton at the same time; phosphoric acid is added because it can passivate some active sites and inhibit Fe 3+Metallic impurities such as phosphoric acid catalyze the deep oxidation of carbon, reducing the breakdown of the carbon structure and inhibiting the over-oxidation of the Si-C skeleton by potassium permanganate (over-oxidation of C generates gases such as CO2, which is then lost as gas, hindering carbon retention and hybridization), thereby reducing the carbon loss rate. If the phosphoric acid ratio is below the above range, the carbon will be over-oxidized into gas, resulting in fewer oxygen-containing functional groups, which is not conducive to the formation of carbon-metal hybrid polymetallic centers and reduces adsorption performance. If the phosphoric acid ratio is above the above range, the reaction activity is low, which is not conducive to the dissolution of some Al in the coal gangue. The formed Si-C skeleton may clog pores, which is not conducive to increasing porosity and reducing adsorption performance.

[0046] In sulfuric acid-phosphoric acid mixed acid, KMnO4 shows strong oxidizing ability, which is beneficial to the oxidation of active sites of carbon components in coal gangue (such as edge carbon, defect sites), etc. The carbon is partially oxidized into oxygen-containing functional groups such as carboxyl and carbonyl. The increased oxygen-containing groups are conducive to the adsorption of metal ions and become subsequent nucleation sites, providing conditions for transformation, growth, and nucleation for the formation of carbon hybrid metal polymetallic centers; the generation of more nucleation sites utilizes the carbon component in coal gangue, which can avoid agglomeration during metal loading, and at the same time greatly reduces the demand for templates (especially alkyl imidazole organic templates) and organic surfactants during metal hybridization, thereby eliminating the above-mentioned ingredients, reducing process complexity, reducing costs, and avoiding the risk of deterioration caused by the addition of inappropriate amounts of templates, surfactants and other ingredients. At the same time, KMnO4 exhibits strong oxidizing ability, which facilitates the partial graphitization of the carbon components in the oxidized coal gangue under enhanced conditions, increasing porosity and facilitating the realization of a stable mesoporous structure. By appropriately adding the appropriate proportion and rationally controlling the oxidizing properties, some of the carbon components exhibit a tendency toward graphene, i.e., the carbon components become flaky and flat, which facilitates the increase of nucleation sites and the formation of carbon-metal hybrid polymetallic centers, thereby enhancing adsorption performance. Potassium permanganate below the above range has insufficient oxidizing properties, while above the above range has excessive oxidizing properties, both of which are detrimental to increasing the proportion of nucleation sites formed, thus affecting the improvement of adsorption performance.

[0047] The above-mentioned treatment temperature is relatively low, so as to avoid adverse effects caused by high temperature such as excessive activity of potassium permanganate, excessive oxidizing property, oxidation of carbon components into gas, etc.

[0048] 5-10 minutes before the end of the treatment time of the above uniform suspension, add 0.01-0.02 mol / L hydrogen peroxide to the solution. After adding hydrogen peroxide (H2O2), it reacts with residual potassium permanganate to generate soluble Mn 2+Ions can terminate the oxidation reaction, moderately control the oxidation intensity, block further carbon reactions, prevent excessive carbon oxidation loss, and promote the stability of graphene-prone carbon. They also increase the number of hydroxyl groups, increase metal ion loading sites, and promote the formation of nucleation sites and carbon-metal hybrid polymetallic centers, thereby enhancing adsorption performance. Adding potassium permanganate too early should be done carefully, as this hinders the potassium permanganate reaction. Adding potassium permanganate too late can hinder the regulation of the oxidation intensity and block excessive carbon reactions.

[0049] Optionally, the gangue is crushed into powder and then calcined at 125-160° C. (optionally 125° C., 129° C., 132° C., 136° C., 138° C., 146° C., 149° C., 155° C., 156° C., 158° C., 160° C., etc.) for 0.7-2 h. During the calcination process, a 0.7-1.1 wt% potassium permanganate aqueous solution (i.e., the mass of potassium permanganate accounts for 0.7-1.1 wt%) is sprayed through a nozzle, the sprayed mass accounts for 0.05-0.08 wt% of the mass of the gangue, and the spraying time is 0.5-1 h.

[0050] By calcining at a relatively low temperature, crystalline aluminum-containing minerals such as kaolinite, the main mineral in the coal gangue, are converted into semi-crystalline or even amorphous minerals such as metakaolinite, whose structure is in a thermodynamically metastable state. The hydroxyl groups (-OH) in the structure are mainly removed, resulting in the breaking of the interlayer hydrogen bonds of the layered silicate, the loosening of the layered structure, and the exposure of more surface active sites (a large number of broken Si-O and Al-O bonds, the formation of surface hydroxyl groups (Si-OH, Al-OH) and defect sites, etc., which are conducive to the reaction and combination with potassium permanganate, hydrochloric acid, phosphoric acid, hydrogen peroxide, soluble silicates and / or soluble silicic acid, alkaline metal compounds, metal salts, etc.); more amorphous phases (such as amorphous silicon dioxide) are produced, which is conducive to the subsequent mixing reaction with potassium permanganate, hydrochloric acid, soluble silicates and / or soluble silicic acid, alkaline metal compounds, metal salts and water. Low-temperature calcination overcomes the shortcomings of the original high-temperature direct sintering layered structure that cannot be fully transformed into a loose structure and the reaction activity cannot be greatly improved. Low-temperature calcination does not completely destroy its layered aluminum silicate skeleton, avoiding the internal pore melting and collapse caused by high-temperature calcination. It still maintains a two-dimensional lamellar structure with an expanded interlayer spacing, providing insertion channels for soluble silicates and metal ions. Low-temperature calcination greatly reduces energy consumption. The main purpose of previous calcination was to remove carbon and activate it. The low-temperature calcination of this application has a different purpose. Through low-temperature calcination, while activating, it reduces carbon combustion losses, which will be beneficial to carbon retention and the generation of active reaction sites, improve porosity, and make the layered silicate mineral have a fine nanoscale pore structure with rich porous silica and porous carbon (i.e., a pore structure of silica-C composite structure), which is conducive to the formation of a richer Si-O-Al skeleton, thereby increasing the load capacity and load stability, thereby improving the adsorption and metal loading capacity. The value of carbon combustion is obviously lower than the value of the composition as an adsorbent material, which also greatly improves the application value of coal gangue and reduces carbon emissions. Using a shorter heat treatment time is more conducive to less carbon loss and higher carbon hybridization ratio.

[0051] Potassium permanganate can release oxygen, MnO2, etc. at temperatures above 120 degrees Celsius, especially above 150 degrees Celsius. MnO2 has a unique redox activity, high specific surface area, porous structure and abundant hydroxyl functional groups on the surface. It has shown significant advantages in removing pollutants such as organic dyes, heavy metals, antibiotics and phosphorus. The hydroxyl groups (-OH) and oxygen vacancies on the surface of MO2 can adsorb heavy metal ions (such as Pb) through complexation. 2+ 、Cd 2+), MnO2 can reduce Cr(VI) to low-toxic and easily precipitated Cr(III), and oxidize the more toxic As(III) to As(V), the latter of which is more easily adsorbed or co-precipitated. The carboxylic acid groups of antibiotic molecules (such as ofloxacin) form hydrogen bonds or coordination bonds with the hydroxyl groups on the surface of MnO2. However, directly soaking the coal gangue in potassium permanganate solution and decomposing it to produce MnO2 can easily clog the coal gangue pores and affect the improvement of adsorption performance; during the low-temperature calcination of coal gangue, oxygen and carbon react slowly, affecting the formation of carbonaceous micropores. During the low-temperature calcination of gangue powder, a low-content potassium permanganate aqueous solution (0.7-1.1wt%) is sprayed into the gangue. The water reacts with the carbon in the gangue to form a water-gas reaction, generating hydrogen, CO, and associated water vapor. This effectively improves gas flow within the gangue's layered structure, facilitates the formation of mesopores with moderate porosity, and enhances the generation of carbonaceous pores. The generated oxygen reacts with the carbon, and with the water to form a water-gas reaction with the carbon in the gangue. This partially consumes the carbon in the gangue (to control the appropriate carbon content), while the generated gas promotes pore formation and improves adsorption performance. The concentration and amount of potassium permanganate aqueous solution should not be too high, as this can lead to excessive or even complete reaction of the carbon, preventing the formation of carbonaceous pores, and resulting in excessive pore size and the risk of explosion due to excessive oxygen generation. The concentration and amount of potassium permanganate aqueous solution should not be too low, as this cannot effectively and quickly form pores, thereby increasing porosity and specific surface area. It is understandable that by spraying potassium permanganate with a lower content without acid, pore formation and activation of coal gangue under low-temperature calcination are facilitated; by adding potassium permanganate and hydrogen peroxide in an acid system, carbon oxygen-containing groups are obtained by regulating the oxidation ability, and the metal ion nucleation core is increased, which is conducive to the formation of more carbon hybrid polymetallic centers.

[0052] (2) Add soluble silicate and / or soluble silicic acid to the suspension obtained above, stir thoroughly, and then ultrasonicate with a cell crusher for 1-10 minutes, and continue magnetic stirring to obtain a uniform suspension A.

[0053] Soluble silicates (such as sodium silicate, etc.) and / or orthosilicic acid are hydrolyzed to form silicate (SiO4 4-) or oligomeric silicic acid, by connecting with active sites in the suspension and Al ions in the solution, for example, through condensation reaction, connecting with the Si-O skeleton and Al ions in the suspension to form cross-Si-O-Al, and the layered open structure of the layered silicate can effectively block and separate and insert soluble silicates and / or orthosilicic acid, and the silicate ions penetrate into the interlayers, filling the interlayer gaps to form a three-dimensional interpenetrating network, thereby enhancing the mechanical strength of the material. The silicate gel shrinks during the pressurized drying process to produce mesopores (2-30nm) (which are conducive to the diffusion of large molecular pollutants), which together with the mesopores and macropores (>30 nm) in the layered silicate mineral structure (reducing mass transfer resistance and providing a stable channel for material migration) form a multi-level pore system, which greatly enriches the pore types and pore density, significantly increases the specific surface area of ​​the material, and improves the adsorption capacity.

[0054] Optionally, the soluble silicate is one or any combination of lithium silicate, sodium silicate, ammonium silicate, and potassium silicate, and the soluble silicic acid is orthosilicic acid. The amount of soluble silicate and / or soluble silicic acid added is 10-50% of the total mass of the suspension, preferably 33-41% (optionally 10%, 16%, 21%, 27%, 33%, 38%, 42%, 47%, 50%, etc.). Controlling the amount of soluble silicate and acid added facilitates the formation of appropriately sized pores through the polycondensation reaction. Too much soluble silicate intercalates and coats the layered silicate, affecting the formation of a multi-level pore system. Too little soluble silicate fills too little void space, hindering the formation of a three-dimensional interpenetrating network and enhancing the mechanical strength of the material while also increasing the pore size. Both too high and too low soluble silicate additions are detrimental to improving adsorption performance. Preferably, a lower range is selected while appropriately controlling the pore diameter.

[0055] Optionally: the soluble silicates are lithium silicate, sodium silicate and potassium silicate, and based on the total mass of the soluble silicates, the ratio of lithium silicate: sodium silicate: potassium silicate is (1.5-1.7): (14-15): (17-18); sodium silicate is hydrolyzed to form silicate ions, and its gelation process is highly controllable and easy to control to form a mesoporous structure; the potassium ion has a larger ionic radius, which is beneficial to delaying the condensation rate and expanding the pore size distribution (mesopores and macropores coexist). By appropriately increasing the potassium ions, the pore size distribution is expanded, which is beneficial to the penetration and loading of metal ions and more uniform distribution; the strong polarization effect of lithium ions promotes the densification of the silicate gel structure, thereby helping to improve the pore strength and maintain pore stability; the sodium, potassium and lithium trication system can balance the gelation rate with structural stability and pore radius, thereby improving adsorption performance.

[0056] (3) Add the alkaline metal compound and metal salt to 30-100 ml (preferably 30-40 ml) of deionized water and magnetically stir to dissolve the metal compound and metal salt to obtain a clear solution B; slowly add the solution B containing the alkaline metal compound and metal salt to the suspension A and continue magnetic stirring for 10-60 minutes to obtain a uniform precursor solution. The magnetic field strength during the above magnetic stirring process is 0.15-0.3 T (optionally 0.15 T, 0.18 T, 0.19 T, 0.21 T, 0.23 T, 0.27 T, 0.3 T, etc.). Using a higher magnetic field strength during the stirring process has a solubilizing effect and is conducive to promoting the uniform dispersion of metal ions.

[0057] Optionally, the metal salt is one or any combination of magnesium carbonate, magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium trisilicate, zinc chloride, zinc sulfate, zinc nitrate, zinc dihydrogen phosphate, calcium halide, calcium carbonate, calcium nitrate, calcium chlorate, calcium perchlorate, calcium bicarbonate, and calcium dihydrogen phosphate, and the amount added is 5-50% of the mass of the soluble silicate and / or soluble silicic acid, preferably 15-25% (optionally 5%, 9%, 10%, 13%, 17%, 21%, 27%, 34%, 37%, 41%, 45%, 48%, 50%, etc.). The appropriate amount of metal salt added supplements and regulates the metal ion composition in the solution, which is conducive to the formation of a multi-metal carbon hybrid crystal structure, especially a reasonable structure close to analcime and promotes the formation of a highly catalytic structure such as analcime crystal structure, with high catalytic ability. Too high or too low an amount is not conducive to the formation of a suitable crystal structure. Preferably, the metal salt is one of magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, and magnesium trisilicate, accounting for 55-85% of the total mass of the metal salt; using a larger proportion of magnesium salts such as magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, and magnesium trisilicate is beneficial to promoting the formation of analcime crystal structure and improving catalytic ability.

[0058] Optionally, the alkaline metal compound is one or any combination of magnesium hydroxide, magnesium oxide, basic magnesium carbonate, zinc oxide, zinc hydroxide, calcium oxide, calcium hydroxide, and dolomite, and is added in an amount of 10-60% by mass of the soluble silicate and / or soluble silicic acid, preferably 21-34% (optionally 10%, 13%, 17%, 21%, 27%, 34%, 37%, 41%, 45%, 48%, 51%, 53%, 57%, 60%, etc.). The alkaline metal compound can promote the hybridization of multiple metals to form a multi-metal composite component and also enhance the strength of the pore structure.

[0059] (4) The precursor solution obtained above is transferred into a closed reactor and heated at a temperature of 60-300°C (optionally 60°C, 61°C, 62°C, 64°C, 69°C, 74°C, 75°C, 78°C, 86°C, 89°C, 93°C, 96°C, 98°C, 107°C, 115°C, 143°C, 152°C, 161°C, 178°C, 183°C, 194°C, 204°C, 235°C, 252°C, 264°C, 284°C, 295°C, 300°C). A magnetic field is applied under pressure conditions of 1-20 MPa (optionally 1 MPa, 5 MPa, 7 MPa, 9 MPa, 11 MPa, 14 MPa, 16 MPa, 18 MPa, 20 MPa, etc.) for 2-36 hours to produce a mixed product containing solid and liquid. The magnetic field strength is 0.45-0.65 T (optionally 0.45 T, 0.48 T, 0.51 T, 0.54 T, 0.58 T, 0.62 T, 0.65 T, etc.). Simultaneously, the above hydrothermal reaction generates a solid carbon hybrid multi-metal central mesoporous material in the solution. The oxygen-containing groups generated in the early stage react with soluble silica substances to form Si-O, Si-OC, Si-OC-Al and other skeletons, as well as a large number of nucleation sites, which provide extremely favorable conditions for the adsorption, nucleation and crystallization of metal ions in the solution. By applying a high-intensity magnetic field, the magnetic field not only has a solubilizing effect, but also facilitates the uniform dispersion and diffusion of metal ions, and facilitates the formation of a large number of small-sized crystal nuclei. Crystallization is carried out on small crystal nuclei, which has a greater effect on promoting the crystallization process, is more conducive to the formation of crystalline structures such as analcime, and improves catalytic ability.

[0060] (5) The mixed product obtained above is subjected to solid-liquid separation to obtain a solid carbon hybrid multi-metal central mesoporous material. The obtained material has the characteristics of high specific surface area and porous structure. The adsorption performance can be improved by dozens of times that of the original coal gangue, which is more efficient in removing pollutants from wastewater and effectively repairing soil seriously polluted by heavy metals.

[0061] Optionally, the powdered coal gangue has a particle size of 62-100 μm (optionally 62 μm, 64 μm, 69 μm, 78 μm, 82 μm, 91 μm, 97 μm, 100 μm, etc.), preferably 68-81 μm. The shortened mass transfer distance within the fine particles facilitates the reaction of organic volatiles (such as tar and hydrocarbons) with potassium permanganate and HCl. Layered silicates such as kaolinite undergo more thorough dehydroxylation within the fine particles, transforming them into the active structure of metakaolinite, which facilitates the formation of uniformly distributed micropores and mesopores.

[0062] Example 1

[0063] A method for synthesizing a carbon hybrid multi-metal center mesoporous material using coal gangue, comprising:

[0064] (1) The gangue was crushed into powder with an average particle size of 69 μm. The powder was then calcined at 134°C for 0.8 h. During the calcination process, a 0.8 wt% potassium permanganate aqueous solution was sprayed through a nozzle, with the sprayed mass accounting for 0.06 wt% of the mass of the gangue, and the spraying time was 0.5. The gangue was crushed into powder (30 g), added to a solution containing 0.13 mol / L potassium permanganate, 3.2 mol / L hydrochloric acid, and 0.6 mol / L phosphoric acid, and treated for 40 min. The powder was dispersed in deionized water under magnetic stirring at a solid-liquid ratio of 18:1 to obtain a uniform suspension. The treatment temperature was 49°C. 6 min before the end of the treatment time of the uniform suspension, 0.01 mol / L hydrogen peroxide was added to the solution.

[0065] (2) Add soluble silicate to the suspension obtained above, stir thoroughly, and then ultrasonicate with a cell crusher for 5 minutes. Continue magnetic stirring to obtain a uniform suspension A. The amount added is 36% of the total mass of the suspension. The soluble silicate is lithium silicate, sodium silicate, and potassium silicate. Based on the total mass of the soluble silicate, the ratio of lithium silicate: sodium silicate: potassium silicate is 1.6:14:18.

[0066] (3) Add the alkaline metal compound and metal salt to 40 ml of deionized water and magnetically stir to dissolve the metal compound and metal salt to obtain a clear solution B. Slowly add the solution B containing the alkaline metal compound and metal salt to the suspension A and continue magnetic stirring for 20 minutes to obtain a uniform precursor solution. The magnetic field strength during the above magnetic stirring process is 0.2 T.

[0067] The metal salt is added in an amount of 16% by mass of the soluble silicate. The metal salt is magnesium chloride, which accounts for 75% of the total mass of the metal salt. The alkaline metal compound is magnesium hydroxide, which is added in an amount of 22% by mass of the soluble silicate.

[0068] (4) The precursor solution obtained above was transferred into a closed reactor and a magnetic field was applied to react for 8 h at a temperature of 89 °C and a pressure of 13 MPa to obtain a mixed product containing solid and liquid. The magnetic field strength was 0.55 T.

[0069] (5) The mixed product obtained above is subjected to solid-liquid separation to obtain a solid carbon hybrid multi-metal central mesoporous material.

[0070] Combine Figure 1-4 As shown in Table 1-2, the carbon hybrid multi-metal central mesoporous material prepared in Example 1 was subjected to SEM testing, and the results are as follows: Figure 1 As shown in the figure, it can be seen that the carbon hybrid multi-metal central mesoporous material prepared by the present invention is in the form of flocculent and clustered shapes and has a porous structure. Nitrogen adsorption and desorption tests and pore size tests were carried out, and the results are as follows Figure 2 、 Figure 3 As shown in the figure, it can be seen that the carbon hybrid multi-metal center mesoporous material is a mesoporous material with a pore size distribution range of 2nm-50nm, and the pore size is mainly concentrated in the range of 2nm-20nm. The pore structure parameters are shown in Table 1. X-ray powder diffraction test, from Figure 4 It can be seen that the carbon hybrid multi-metal center mesoporous material prepared by the present invention has a basically consistent crystal structure with that of analcime. As can be seen from Table 2, compared with the direct adsorption of raw coal gangue and coal gangue calcined at 300°C as adsorbents, the saturated adsorption capacity for phosphate, tetracycline, Cd (II) and Pb (II) is very small. The saturated adsorption capacity of the carbon hybrid multi-metal center mesoporous material of Example 1 for phosphate, tetracycline, Cd (II) and Pb (II) is increased by dozens of times, and it has a good ability to remove the above components. Among them Figure 3 This is the pore size distribution curve of the carbon hybrid multi-metal center mesoporous material of Example 1, where the ordinate is dV / dlogD, representing the pore volume change (dV) within the unit logarithmic pore size interval (dlogD), unit: cm³ / g; the abscissa is the pore diameter, unit: nm.

[0071] Table 1 Pore structure parameters of carbon hybrid multi-metal center mesoporous materials

[0072]

[0073] Table 2 Saturated adsorption capacity of carbon hybrid multimetallic center mesoporous materials for phosphate, tetracycline, Cd(II), and Pb(II) (mg / g)

[0074]

[0075] Example 2

[0076] The method is basically the same as that of Example 1, except that in step (1), the gangue is crushed into powder without calcination and spraying with potassium permanganate. Compared with Example 1, the uncalcined porosity is not high, which is not conducive to improving the adsorption performance.

[0077] Example 3

[0078] The method is basically the same as that in Example 1, except that potassium permanganate solution is not sprayed during the calcination process.

[0079] Example 4

[0080] The method is basically the same as that in Example 1, except that 0.3 wt % potassium permanganate aqueous solution is sprayed.

[0081] Example 5

[0082] The method is basically the same as that in Example 1, except that a 2.1 wt % potassium permanganate aqueous solution is sprayed.

[0083] Example 6

[0084] The method is basically the same as that in Example 1, except that the ratio of lithium silicate: sodium silicate: potassium silicate is 1.6:14:7.

[0085] Example 7

[0086] The method is basically the same as that in Example 1, except that the metal salt is zinc sulfate.

[0087] Comparative Example 1

[0088] The method is basically the same as that in Example 1, except that 0.04 mol / L potassium permanganate is added.

[0089] Comparative Example 2

[0090] The method is basically the same as that in Example 1, except that 0.4 mol / L potassium permanganate is added.

[0091] Comparative Example 3

[0092] The method is basically the same as that of Example 1, except that phosphoric acid is not added.

[0093] Comparative Example 4

[0094] The method is basically the same as that in Example 1, except that hydrogen peroxide is not added.

[0095] Comparative Example 5

[0096] The method is basically the same as that in Example 1, except that the magnetic field strength is 0.1T.

[0097] Comparative Example 6

[0098] The method is basically the same as that in Example 1, except that the magnetic field intensity during the magnetic stirring process is 0.1 T.

[0099] Comparative Example 7

[0100] The method is basically the same as that of Example 2, except that: hydrogen peroxide is not added, but 0.5 mol / L potassium permanganate is added.

[0101] Comparative Example 8

[0102] The method is basically the same as that of Example 7, except that no magnetic field is applied.

[0103] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the above embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue, characterized in that: include: (1) Grind the coal gangue into powder (10-60 g), add it to a solution containing 0.09-0.15 mol / L potassium permanganate, 2-5 mol / L hydrochloric acid, and 0.5-1 mol / L phosphoric acid; disperse it in deionized water under the action of magnetic stirring at a solid-liquid ratio of 10:1-100:1 (g / L) to obtain a uniform suspension; the treatment temperature is 45-73°C, and the treatment time is 30-130 min; 5-10 min before the end of the suspension treatment time, add 0.01-0.02 mol / L hydrogen peroxide to the solution; (2) Add soluble silicate and / or soluble silicic acid to the suspension obtained above, stir thoroughly, and then ultrasonicate with a cell crusher for 1-10 minutes, and continue magnetic stirring to obtain a uniform suspension A; (3) Add the alkaline metal compound and the metal salt to 30-100 ml of deionized water and stir magnetically to dissolve the metal compound and the metal salt to obtain a clear solution B; Slowly add solution B containing alkaline metal compounds and metal salts to suspension A and continue magnetic stirring for 10-60 minutes to obtain a uniform precursor solution; The magnetic field strength during the magnetic stirring process is 0.15-0.3T; (4) The precursor solution obtained above is transferred into a closed reactor, and a magnetic field is applied to react for 2-36 hours at a temperature of 60-300°C and a pressure of 1-20 MPa to obtain a mixed product containing solid and liquid. The magnetic field strength is 0.45-0.65 T. (5) The mixed product obtained above is subjected to solid-liquid separation to obtain a solid carbon hybrid multi-metal central mesoporous material.

2. The method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue according to claim 1, characterized in that: In step (1), the gangue is crushed into powder and then calcined at 125-160° C. During the calcination process, a 0.7-1.1 wt % potassium permanganate aqueous solution is sprayed through a nozzle, the sprayed mass accounts for 0.05-0.08 wt % of the mass of the gangue, and the spraying time is 0.5-1 h.

3. The method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue according to claim 1, characterized in that: The soluble silicate in step (2) is one or any combination of lithium silicate, sodium silicate, ammonium silicate, and potassium silicate, the soluble silicic acid is orthosilicic acid, and the amount of soluble silicate and / or soluble silicic acid added is 10-50% of the total mass of the suspension.

4. The method for synthesizing carbon hybrid multi-metallic center mesoporous materials using coal gangue according to claim 3, characterized in that: The soluble silicates in step (2) are lithium silicate, sodium silicate and potassium silicate. Based on the total mass of the soluble silicates, the ratio of lithium silicate: sodium silicate: potassium silicate is (1.5-1.7): (14-15): (17-18).

5. The method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue according to claim 1, characterized in that: The metal salt in step (3) is one or any combination of magnesium carbonate, magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, magnesium trisilicate, zinc chloride, zinc sulfate, zinc nitrate, zinc dihydrogen phosphate, calcium halide, calcium carbonate, calcium nitrate, calcium chlorate, calcium perchlorate, calcium bicarbonate, and calcium dihydrogen phosphate, and the added amount is 5-50% of the mass of the soluble silicate and / or soluble silicic acid.

6. The method for synthesizing carbon hybrid multi-metallic center mesoporous materials using coal gangue according to claim 5, characterized in that: The metal salt in step (3) is one of magnesium chloride, magnesium sulfate, magnesium nitrate, magnesium acetate, and magnesium trisilicate, accounting for 55-85% of the total mass of the metal salt.

7. The method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue according to claim 1, characterized in that: In step (3), the alkaline metal compound is one or any combination of magnesium hydroxide, magnesium oxide, basic magnesium carbonate, zinc oxide, zinc hydroxide, calcium oxide, calcium hydroxide, and dolomite, and the amount added is 10-60% of the mass of the soluble silicate and / or soluble silicic acid.

8. The method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue according to claim 1, characterized in that: The particle size of the powder of the coal gangue after crushing in step (1) is 62-100 μm.

9. The method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue according to claim 1, characterized in that: The treatment temperature in step (1) is 45-53°C.

10. The method for synthesizing carbon hybrid multi-metal central mesoporous materials using coal gangue according to claim 3, characterized in that: In step (2), the amount of soluble silicate and / or soluble silicic acid added is 33-41% of the total mass of the suspension.

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