CN108911599B - Method for simultaneously preparing iron oxide and silicon dioxide aerogel pad from iron tailings - Google Patents

Method for simultaneously preparing iron oxide and silicon dioxide aerogel pad from iron tailings Download PDF

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CN108911599B
CN108911599B CN201810790735.7A CN201810790735A CN108911599B CN 108911599 B CN108911599 B CN 108911599B CN 201810790735 A CN201810790735 A CN 201810790735A CN 108911599 B CN108911599 B CN 108911599B
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iron
iron tailings
pad
iron oxide
silica aerogel
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CN108911599A (en
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王建国
宋鑫
包志康
张志军
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Zhejiang University of Technology ZJUT
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    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B28/00—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements
    • C04B28/005—Compositions of mortars, concrete or artificial stone, containing inorganic binders or the reaction product of an inorganic and an organic binder, e.g. polycarboxylate cements containing gelatineous or gel forming binders, e.g. gelatineous Al(OH)3, sol-gel binders
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B82—NANOTECHNOLOGY
    • B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
    • B82Y40/00—Manufacture or treatment of nanostructures
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01G—COMPOUNDS CONTAINING METALS NOT COVERED BY SUBCLASSES C01D OR C01F
    • C01G49/00—Compounds of iron
    • C01G49/02—Oxides; Hydroxides
    • C01G49/06—Ferric oxide (Fe2O3)
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2004/00—Particle morphology
    • C01P2004/60—Particles characterised by their size
    • C01P2004/64—Nanometer sized, i.e. from 1-100 nanometer
    • C—CHEMISTRY; METALLURGY
    • C01—INORGANIC CHEMISTRY
    • C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
    • C01P2006/00—Physical properties of inorganic compounds
    • C01P2006/11—Powder tap density
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B2201/00—Mortars, concrete or artificial stone characterised by specific physical values
    • C04B2201/20—Mortars, concrete or artificial stone characterised by specific physical values for the density

Abstract

The invention discloses a method for simultaneously preparing iron oxide and silicon dioxide aerogel cushions from iron tailings. The method comprises the steps of taking iron tailings as raw materials, sequentially grinding and crushing, roasting at high temperature and activating, mixing activated iron tailing powder with hydrochloric acid, stirring and reacting to obtain filter residues and filtrate; mixing and roasting filter residues and sodium hydroxide particles, then melting the mixture into water for heating reaction, passing through cation exchange resin, adjusting the mixture to be neutral by using an ammonia water solution, immersing the mixture into a glass fiber felt, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, standing for gelation to obtain a gel pad, and then aging, solvent exchange and surface modification are carried out to obtain a hydrophobic silica aerogel pad; adjusting pH of the filtrate to alkalescence with ammonia water, standing, filtering, and drying to obtain ferric oxide nanopowder. The whole process has the advantages of cheap and easily-obtained raw materials, low requirement on equipment, mild reaction conditions, capability of treating a large amount of solid waste such as iron tailings and high application value.

Description

Method for simultaneously preparing iron oxide and silicon dioxide aerogel pad from iron tailings
Technical Field
The invention belongs to the field of inorganic materials, and particularly relates to a method for simultaneously preparing iron oxide and a silicon dioxide aerogel cushion from iron tailings.
Background
The total development scale of mineral resources in China is in the front of the world, and the outstanding characteristics of iron ore resources in China are low grade and more symbiotic associated ores, so that a large amount of iron tailings can be generated in the ore dressing process, and 2.5-3.0t of tailings are discharged when 1t of iron concentrate is produced. The iron tailings not only occupy a large amount of land, but also pollute soil, water, air and the like, destroy the ecological environment and have great influence.
At present, the comprehensive utilization rate of the iron tailings is low and is less than 20%, most of the iron tailings are used as building fillers, and high-end products are few, mainly because the preparation process is complex, the reaction conditions are harsh and the like, so that the iron tailings cannot be produced in large quantities.
The iron oxide micropowder is an important industrial raw material, has the advantages of light resistance, chemical corrosion resistance, no toxicity and the like, has good dispersibility, tinting strength and ultraviolet absorption capability, and can be used in a plurality of fields such as buildings, coatings, iron metallurgy and the like.
The silicon dioxide aerogel is an inorganic material with high porosity, has the characteristic that common inorganic materials are not easy to burn, has stronger heat preservation performance of organic foam materials, and is a high-quality heat insulation material. However, due to the characteristic that the material is easy to crack, the application space of the material is limited, and a heat insulation material with good heat insulation and heat preservation performance and good mechanical performance is urgently needed.
Aiming at the technical background, the iron tailings are used as raw materials, the iron element can be collected to the maximum extent by preparing the iron oxide powder and the silica aerogel pad at the same time, the silica aerogel pad which has strong heat insulation performance and is not easy to crack is also prepared, and when the iron tailings are treated in a large quantity, a material with good heat insulation performance can be produced, so that the method has great significance.
Disclosure of Invention
Aiming at the defects of the prior art, the invention provides a method for simultaneously preparing iron oxide powder and a silicon dioxide aerogel pad by using iron tailings as raw materials, the method can treat a large amount of solid waste of the iron tailings, the reaction condition is mild, the industrialization is easy, and the prepared silicon dioxide aerogel pad and the prepared iron oxide powder are widely applied.
The method for simultaneously preparing the iron oxide and the silicon dioxide aerogel cushion from the iron tailings is characterized by mainly comprising the following steps of:
1) grinding and crushing the iron tailings and sieving the iron tailings with a 100-mesh sieve to obtain finely ground iron tailings;
2) placing the finely ground iron tailings obtained in the step 1) into a muffle furnace, heating to 850-950 ℃, activating, preserving heat for 4.5-5.5 hours, cooling to normal temperature to obtain activated iron tailing powder, mixing the activated iron tailing powder with hydrochloric acid, stirring for reaction, filtering after the reaction is finished, drying filter residues, and collecting filtrate by using a container;
3) mixing the filter residue dried in the step 2) with sodium hydroxide particles, uniformly stirring, keeping the mixture in a muffle furnace at the temperature of 500-600 ℃ for 1.5-2.5 hours, melting the obtained iron tailings after the alkali fusion reaction into water for heating reaction, and filtering to obtain a crude silicon solution after the reaction is finished;
4) passing the crude silicon solution prepared in the step 3) through cation exchange resin, adjusting the pH value to 6.5-7.5 by using an ammonia water solution, immersing a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation to obtain a gel pad;
5) aging the gel: adding the gel aging liquid into the gel pad prepared in the step 4), standing and aging at room temperature to obtain an aged gel pad;
6) solvent exchange: immersing the gel pad aged in the step 5) into n-hexane for 22-26 hours to displace water in the gel to obtain a colloid;
7) surface modification: immersing the colloid prepared in the step 6) into the modified solution, standing for 12-24 hours at room temperature, and finally drying the prepared gel at 90-120 ℃ under normal pressure for 6-8 hours to obtain a hydrophobic silica aerogel pad prepared by taking iron tailings as a raw material;
8) adjusting the pH of the filtrate obtained in the step 2) to 7-8 by using ammonia water under an ultrasonic environment, allowing a large amount of precipitate to appear, standing, filtering, drying filter residue, putting the filter residue into a muffle furnace, and roasting at the temperature of 600-700 ℃ for 1.5-2.5 hours to finally obtain the iron oxide nano powder.
The method for simultaneously preparing the iron oxide and the silicon dioxide aerogel cushion from the iron tailings is characterized in that the components of the iron tailings in the step 1) comprise SiO2、CaO、MgO、Al2O3、Fe2O3。
The method for simultaneously preparing the iron oxide and silicon dioxide aerogel pad from the iron tailings is characterized in that the hydrochloric acid concentration in the step 2) is 1-3mol/L, preferably 2mol/L, and the volume ratio of the activated tailing powder to the hydrochloric acid is 1: 1.5-2.1, preferably 1.6-1.8.
The method for simultaneously preparing the ferric oxide and the silicon dioxide aerogel pad from the iron tailings is characterized in that the mass ratio of the filter residue to the sodium hydroxide in the step 3) is 1:1.5-2, the iron tailings after the alkali dissolution reaction are stirred and reacted at the temperature of 60-90 ℃ according to the solid-to-liquid ratio of 1:3-7, and a crude silicon solution is obtained by filtering.
The method for simultaneously preparing the ferric oxide and the silicon dioxide aerogel pad from the iron tailings is characterized in that 2-4mol/L ammonia water solution is added into the crude silicon solution in the step 4) to adjust the pH value, and after the crude silicon solution is uniformly immersed into a glass fiber mat, the mat is hardened to obtain gel.
The method for simultaneously preparing the iron oxide and silicon dioxide aerogel pad from the iron tailings is characterized in that the aging solution in the step 5) is a mixed solution of absolute ethyl alcohol and tetraethoxysilane, and the volume ratio of the absolute ethyl alcohol to the tetraethoxysilane is 8-12: 1.
the method for simultaneously preparing the iron oxide and the silicon dioxide aerogel pad from the iron tailings is characterized in that in the step 7), the modification liquid is a mixed liquid of n-hexane and trimethylchlorosilane, and the volume ratio of the n-hexane to the trimethylchlorosilane is 8-12: 1, preferably 10: 1.
The method for simultaneously preparing the iron oxide and the silicon dioxide aerogel pad from the iron tailings is characterized in that the density of the obtained silicon dioxide aerogel pad is 0.162-0.173g/cm3(ii) a The tap density of the ferric oxide nano powder is 1.063-1.141 g/cm3The particle size is less than 50 nm.
By adopting the technology, compared with the prior art, the invention has the following beneficial effects:
1) according to the invention, solid wastes such as iron tailings and the like are used as raw materials, iron and silicon elements in the solid wastes are reasonably utilized, and the hydrophobic silica aerogel pad is prepared by utilizing a cheap silicon source in the iron tailings; meanwhile, iron in the iron tailings is recycled to prepare iron oxide, and the hydrophobic silica aerogel and the iron oxide are used for the next comprehensive utilization, so that the purpose of treating a large amount of iron tailings is realized, the environmental pressure is relieved, the environmental pollution is reduced, the recycling rate is improved, and the requirement of environmental protection is met;
2) the invention overcomes the characteristic of easy fragmentation of the silicon dioxide aerogel while maintaining the extremely high heat preservation and insulation effect of the silicon dioxide aerogel, and greatly improves the mechanical strength of the silicon dioxide aerogel;
3) the invention provides a normal pressure drying method with mild reaction and short preparation time, which is more beneficial to industrial production than the common supercritical drying method;
4) the invention can obtain the iron oxide powder which can be used as a coloring agent of paint rubber and the like and other industrial purposes while preparing the silicon dioxide aerogel cushion.
Drawings
FIG. 1 is a flow chart of an embodiment of the present invention;
FIG. 2 is an SEM image of a silica aerogel pad made according to example 1 of the present invention;
FIG. 3 is a graph of Fourier Infrared (FTIR) analysis of a silica aerogel mat made in accordance with example 1 of the present invention;
FIG. 4 is an SEM photograph of an iron oxide powder obtained in example 1 of the present invention;
FIG. 5 is a schematic representation of a silica aerogel blanket made in accordance with example 1 of the present invention.
Detailed Description
The technical solution of the present invention is further illustrated by the following specific examples, but the scope of the present invention is not limited thereto:
example 1 preparation of iron oxide powder and silica aerogel pad
As shown in fig. 1, the preparation method of the iron oxide powder and the silica aerogel pad using the iron tailings as the raw material in the embodiment 1 of the present invention includes the following steps:
(1) the raw material at least comprises iron tailings (SiO) in North China245.43%、CaO 13.81%、MgO 13.10%、Al2O311.35%、Fe2O310.13 percent, and the balance being impurities), sodium hydroxide, hydrochloric acid, concentrated ammonia water, glass fiber felt, normal hexane, trimethylchlorosilane and absolute ethyl alcohol;
(2) sieving the milled iron tailings with a 100-mesh sieve, then placing the iron tailings into a muffle furnace, heating the iron tailings to 850 ℃, keeping the temperature for 4.5 hours, cooling the iron tailings to the normal temperature, mixing the iron tailings with 2mol/L hydrochloric acid according to the volume ratio of 1:1.5, stirring the mixture for 2 hours, filtering the mixture to obtain filter residues, drying the filter residues, and collecting the filtrate by using a container;
(3) mixing the filter residue and sodium hydroxide according to the mass ratio of 1:1.5, uniformly stirring, heating to 500 ℃, keeping for 1.5 hours, taking out, melting into water, stirring and reacting at 60 ℃ for 24 hours according to the solid-liquid ratio of 1:3, and filtering to obtain a crude silicon solution;
(4) passing the crude silicon solution through cation exchange resin, then adjusting the pH value to be =6.5 by using 2mol/L ammonia water solution, immersing the crude silicon solution into a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation;
(5) aging the gel: immersing the prepared gel pad into gel aging solution (anhydrous ethanol and tetraethoxysilane are mixed according to the volume of 10: 1), standing at room temperature for 20 hours and aging;
(6) solvent exchange: soaking the aged gel pad into n-hexane for 22 hours for solvent exchange, and displacing water in the gel pad;
(7) surface modification: immersing the prepared colloid into a modification solution (n-hexane and trimethylchlorosilane are mixed according to the volume ratio of 10: 1), standing for 12 hours at room temperature, and finally drying the prepared gel at 90 ℃ under normal pressure for 6 hours to finally obtain a hydrophobic silica aerogel pad prepared by taking iron tailings as a raw material, wherein a physical diagram of the hydrophobic silica aerogel pad is shown in fig. 5;
(8) and (3) adjusting the iron-containing filtrate obtained in the step (2) to pH =7 by using ammonia water in an ultrasonic environment, allowing a large amount of precipitate to appear, standing for 2 hours, filtering, drying filter residues, putting the filter residues into a muffle furnace, and roasting at the temperature of 600 ℃ for 1.5 hours to finally obtain the iron oxide nano powder. And the performance parameters of the obtained iron oxide and silicon dioxide aerogel cushion are measured, and the method comprises the following specific steps:
1) scanning Electron Microscope (SEM) analysis of aerogel blanket prepared in example 1
FIG. 2 is a microstructure of a silica aerogel blanket under a scanning electron microscope. As can be seen from fig. 2, the porous silica aerogel is attached to the glass fiber to fix the glass fiber filaments together, so that the defect that the silica aerogel is soft and fragile is overcome, and the porous silica aerogel belongs to a typical composite aerogel structure;
2) fourier Infrared (FTIR) analysis of the aerogel prepared in example 1
FIG. 3 is a Fourier transform infrared spectrum of a silica aerogel. FromAs can be seen in fig. 3: at 1090 cm-1The strong and wide peak is a Si-O-Si vibration peak; the silica aerogel is proved to be a three-dimensional network structure consisting of Si-O-Si;
3) scanning Electron Microscope (SEM) analysis of the iron oxide powder prepared in example 1
FIG. 4 shows the microstructure of iron oxide powder under an electron scanning microscope. As can be seen from the figure, the prepared iron oxide powder is short rod-shaped particles, has uniform particle size distribution of less than 50nm, and belongs to the field of nano materials.
Example 2 preparation of iron oxide powder and silica aerogel pad
The embodiment 2 of the invention takes iron tailings as raw materials to prepare iron oxide powder and silicon dioxide aerogel pads, and comprises the following steps:
(1) the raw materials at least comprise iron tailings in North China, sodium hydroxide, hydrochloric acid, concentrated ammonia water, glass fiber, normal hexane, trimethylchlorosilane and absolute ethyl alcohol;
(2) sieving the milled iron tailings with a 100-mesh sieve, then placing the iron tailings into a muffle furnace, heating the iron tailings to 950 ℃, keeping the temperature for 5.5 hours, cooling the iron tailings to normal temperature, mixing the iron tailings with 2mol/L hydrochloric acid according to the volume ratio of 1:2.1, stirring the mixture for 4 hours, filtering the mixture to obtain filter residues, drying the filter residues, and collecting the filtrate by using a container;
(3) mixing the filter residue and sodium hydroxide according to the mass ratio of 1:2, uniformly stirring, heating to 600 ℃, keeping for 2.5 hours, taking out, melting into water, stirring and reacting at 90 ℃ for 27 hours according to the solid-liquid ratio of 1:7, and filtering to obtain a crude silicon solution;
(4) passing the crude silicon solution through cation exchange resin, then adjusting the pH value to be =7.5 by using 2mol/L ammonia water solution, immersing the crude silicon solution into a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation;
(5) aging the gel: immersing the prepared gel pad into gel aging solution (anhydrous ethanol and tetraethoxysilane are mixed according to the volume of 10: 1), standing at room temperature for 26 hours and aging;
(6) solvent exchange: immersing the aged gel pad into n-hexane for 26 hours for solvent exchange, and displacing water in the gel pad;
(7) surface modification: immersing the prepared colloid into a modification solution (mixing n-hexane and trimethylchlorosilane according to the volume ratio of 10: 1), standing for 24 hours at room temperature, and finally drying the prepared gel at 120 ℃ under normal pressure for 8 hours to finally obtain a hydrophobic silica aerogel pad prepared by taking iron tailings as a raw material;
(8) and (3) adjusting the iron-containing filtrate obtained in the step (2) to pH =8 by using ammonia water in an ultrasonic environment, allowing a large amount of precipitate to appear, standing for 2 hours, filtering, drying filter residues, putting the filter residues into a muffle furnace, and roasting at the temperature of 700 ℃ for 2.5 hours to obtain the iron oxide nano powder. And the performance parameters of the obtained iron oxide and silica aerogel pad are measured, and the performance parameters of the iron oxide and silica nano material are measured in the same way as in example 1.
Example 3 preparation of iron oxide powder and silica aerogel pad
The embodiment 3 of the invention takes iron tailings as raw materials to prepare the iron oxide powder and the silicon dioxide aerogel cushion, and comprises the following steps:
(1) the raw materials at least comprise iron tailings in North China, sodium hydroxide, hydrochloric acid, concentrated ammonia water, glass fiber, normal hexane, trimethylchlorosilane and absolute ethyl alcohol;
(2) sieving the milled iron tailings with a 100-mesh sieve, then placing the iron tailings into a muffle furnace, heating the iron tailings to 900 ℃, keeping the temperature for 5 hours, cooling the iron tailings to the normal temperature, mixing the iron tailings with 2mol/L hydrochloric acid according to the volume ratio of 1:1.8, stirring the mixture for 4.5 hours, filtering the mixture to obtain filter residues, drying the filter residues, and collecting filtrate by using a container;
(3) mixing the filter residue and sodium hydroxide according to a mass ratio of 1:1.7, uniformly stirring, heating to 550 ℃, keeping for 2 hours, taking out, melting into water, stirring and reacting at 85 ℃ for 25 hours according to a solid-liquid ratio of 1:5, and filtering to obtain a crude silicon solution;
(4) passing the crude silicon solution through cation exchange resin, then adjusting the pH value to be =7 by using 2mol/L ammonia water solution, immersing the crude silicon solution into a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation;
(5) aging the gel: immersing the prepared gel pad into gel aging solution (anhydrous ethanol and tetraethoxysilane are mixed according to the volume of 10: 1), standing at room temperature for 25 hours and aging;
(6) solvent exchange: soaking the aged gel pad into n-hexane for 24 hours for solvent exchange, and displacing water in the gel pad;
(7) surface modification: immersing the prepared colloid into a modification solution (mixing n-hexane and trimethylchlorosilane according to the volume ratio of 10: 1), standing for 14 hours at room temperature, and finally drying the prepared gel at 80 ℃ under normal pressure for 6 hours to finally obtain a hydrophobic silica aerogel pad prepared by taking iron tailings as a raw material;
(8) and (3) adjusting the iron-containing filtrate obtained in the step (2) to pH =7.5 by using ammonia water in an ultrasonic environment, allowing a large amount of precipitate to appear, standing for 2 hours, filtering, drying filter residues, putting the filter residues into a muffle furnace, and roasting at 650 ℃ for 2 hours to obtain the iron oxide nano powder. And the performance parameters of the obtained iron oxide and silica aerogel pad are measured, and the performance parameters of the iron oxide and silica nano material are measured in the same way as in example 1.
Example 3 preparation of iron oxide powder and silica aerogel pad
The embodiment 3 of the invention takes iron tailings as raw materials to prepare the iron oxide powder and the silicon dioxide aerogel cushion, and comprises the following steps:
(1) the raw materials at least comprise iron tailings in North China, sodium hydroxide, hydrochloric acid, concentrated ammonia water, glass fiber, normal hexane, trimethylchlorosilane and absolute ethyl alcohol;
(2) sieving the milled iron tailings with a 100-mesh sieve, then placing the iron tailings into a muffle furnace, heating the iron tailings to 920 ℃, keeping the temperature for 5 hours, cooling the iron tailings to normal temperature, mixing the iron tailings with 2mol/L hydrochloric acid according to the volume ratio of 1:1.7, stirring the mixture for 4.5 hours, filtering the mixture to obtain filter residues, drying the filter residues, and collecting the filtrate by using a container;
(3) mixing the filter residue and sodium hydroxide according to a mass ratio of 1:1.5, uniformly stirring, heating to 520 ℃, keeping for 2.5 hours, taking out, melting into water, stirring and reacting at 80 ℃ for 23 hours according to a solid-liquid ratio of 1:6, and filtering to obtain a crude silicon solution;
(4) passing the crude silicon solution through cation exchange resin, then adjusting the pH value to be =7.5 by using 2mol/L ammonia water solution, immersing the crude silicon solution into a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation;
(5) aging the gel: immersing the prepared gel pad into gel aging solution (anhydrous ethanol and tetraethoxysilane are mixed according to the volume of 10: 1), standing at room temperature for 26 hours and aging;
(6) solvent exchange: soaking the aged gel pad into n-hexane for 22 hours for solvent exchange, and displacing water in the gel pad;
(7) surface modification: immersing the prepared colloid into a modification solution (mixing n-hexane and trimethylchlorosilane according to the volume ratio of 10: 1), standing for 16 hours at room temperature, and finally drying the prepared gel at 90 ℃ under normal pressure for 7 hours to finally obtain a hydrophobic silica aerogel pad prepared by taking iron tailings as a raw material;
(8) and (3) adjusting the pH of the iron-containing filtrate obtained in the step (2) to be 7.5 by using ammonia water in an ultrasonic environment, allowing a large amount of precipitates to appear, standing for 2 hours, filtering, drying filter residues, putting the filter residues into a muffle furnace, roasting at 680 ℃ for 2 hours, and finally obtaining the iron oxide nano powder. And the performance parameters of the obtained iron oxide and silica aerogel pad are measured, and the performance parameters of the iron oxide and silica nano material are measured in the same way as in example 1.
Comparative example 1 preparation of iron oxide powder and silica aerogel pad
Comparative example 1 of the present invention, which uses iron tailings as a raw material to prepare an iron oxide powder and a silica aerogel pad, includes the following steps:
(1) the raw materials at least comprise iron tailings in North China, sodium hydroxide, hydrochloric acid, concentrated ammonia water, glass fiber, normal hexane, trimethylchlorosilane and absolute ethyl alcohol;
(2) sieving the milled iron tailings with a 100-mesh sieve, then placing the iron tailings into a muffle furnace to be heated to 900 ℃, keeping the temperature for 5 hours, cooling the iron tailings at normal temperature, mixing the iron tailings with 2mol/L hydrochloric acid according to the volume ratio of 1:1.5, stirring the mixture for 2 hours, filtering the mixture to obtain filter residues, drying the filter residues, and collecting the filtrate by using a container;
(3) mixing the filter residue and sodium hydroxide according to a mass ratio of 1:1.5, uniformly stirring, heating to 500 ℃, keeping for 1 hour, taking out, melting into water, stirring and reacting at 60 ℃ for 24 hours according to a solid-liquid ratio of 1:3, and filtering to obtain a crude silicon solution;
(4) adjusting the crude silicon solution to be near neutral by using 2mol/L hydrochloric acid, immersing the crude silicon solution into a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation;
(5) aging the gel: immersing the prepared gel pad into gel aging solution (anhydrous ethanol and tetraethoxysilane are mixed according to the volume of 10: 1), standing at room temperature for 20 hours and aging;
(6) solvent exchange: soaking the aged gel pad into n-hexane for 20 hours for solvent exchange, and displacing water in the gel pad;
(7) surface modification: immersing the prepared colloid into a modification solution (mixing n-hexane and trimethylchlorosilane according to the volume ratio of 10: 1), standing for 20 hours at room temperature, and finally drying the prepared gel at 70 ℃ under normal pressure for 6 hours to finally obtain the hydrophobic silica aerogel pad prepared by taking the iron tailings as the raw material.
Comparative example 2 preparation of iron oxide powder and silica aerogel pad
In comparative example 2 of the present invention, iron oxide powder and silica aerogel pad are prepared using iron tailings as raw materials, and the method comprises the following steps:
(1) the raw materials at least comprise iron tailings in North China, sodium hydroxide, hydrochloric acid, concentrated ammonia water, glass fiber, normal hexane, trimethylchlorosilane and absolute ethyl alcohol;
(2) sieving the milled iron tailings with a 100-mesh sieve, then placing the iron tailings into a muffle furnace to be heated to 900 ℃, keeping the temperature for 5 hours, cooling the iron tailings at normal temperature, mixing the iron tailings with 2mol/L hydrochloric acid according to the volume ratio of 1:2.1, stirring the mixture for 4 hours, filtering the mixture to obtain filter residues, drying the filter residues, and collecting the filtrate by using a container;
(3) mixing the filter residue and sodium hydroxide according to the mass ratio of 1:2, uniformly stirring, heating to 500 ℃, keeping for 3 hours, taking out, melting into water, stirring and reacting at 90 ℃ for 28 hours according to the solid-liquid ratio of 1:7, and filtering to obtain a crude silicon solution;
(4) passing the crude silicon solution through cation exchange resin, adjusting to be near neutral by using 2mol/L ammonia water solution, immersing the crude silicon solution into a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation;
(5) aging the gel: immersing the prepared gel pad into gel aging solution (anhydrous ethanol and tetraethoxysilane are mixed according to the volume of 10: 1), standing at room temperature for 26 hours and aging;
(6) surface modification: immersing the prepared colloid into a modification solution (mixing n-hexane and trimethylchlorosilane according to the volume ratio of 10: 1), standing for 24 hours at room temperature, and finally drying the prepared gel at 80 ℃ under normal pressure for 8 hours to finally obtain the hydrophobic silica aerogel pad prepared by taking the iron tailings as the raw material.
Through the above two comparative examples, comparative example 1 does not perform a cation exchange operation on the crude silicon solution in step (4), and directly adjusts the pH to be neutral to wait for gelation, compared with the original method, the finally prepared silica aerogel cushion is soft, the glass fiber is exposed, and substantially no gel is formed in the preparation process; comparative example 2 the solvent exchange operation was not performed after the gel was aged in step (5), so that the mechanical strength of the silica aerogel mat was not high, mainly because water has a large surface tension and the pores were collapsed when the silica wet gel was dried, resulting in no formation of the silica aerogel mat.
As can be seen from the above examples and comparative examples, the present invention provides a method for simultaneously preparing iron oxide powder and silica aerogel mat using iron tailings as raw materials, comprising: recovering elements such as iron, silicon, aluminum and the like which are rich in the iron tailings; obtaining a cheap silicon source for preparing the silicon dioxide aerogel pad; after a series of aging, solvent exchange and surface modification, drying the prepared silicon dioxide aerogel pad under normal pressure; the prepared iron oxide powder also has wide application in the fields of paint, building and the like. The iron oxide powder and the silicon dioxide aerogel pad provided by the invention have the advantages of mild preparation conditions, short preparation period, large amount of solid waste treatment and easiness in industrialization.
The above description is only a few examples of the present invention, and is not intended to limit the present invention. But all equivalent changes and modifications made according to the contents of the present invention are within the scope of the present invention.

Claims (10)

1. A method for simultaneously preparing iron oxide and silica aerogel mats from iron tailings, characterized by comprising the steps of:
1) grinding and crushing the iron tailings and sieving the iron tailings with a 100-mesh sieve to obtain finely ground iron tailings;
2) placing the finely ground iron tailings obtained in the step 1) into a muffle furnace, heating to 850-950 ℃, activating, preserving heat for 4.5-5.5 hours, cooling to normal temperature to obtain activated iron tailing powder, mixing the activated iron tailing powder with hydrochloric acid, stirring for reaction, filtering after the reaction is finished, drying filter residues, and collecting filtrate by using a container;
3) mixing the filter residue dried in the step 2) with sodium hydroxide particles, uniformly stirring, keeping the mixture in a muffle furnace at the temperature of 500-600 ℃ for 1.5-2.5 hours, melting the obtained iron tailings after the alkali fusion reaction into water for heating reaction, and filtering to obtain a crude silicon solution after the reaction is finished;
4) passing the crude silicon solution prepared in the step 3) through cation exchange resin, adjusting the pH value to 6.5-7.5 by using an ammonia water solution, immersing a glass fiber felt when the crude silicon solution is not gelled, repeatedly extruding the glass fiber felt to uniformly distribute silica sol into the glass fiber felt, and standing for gelation to obtain a gel pad;
5) aging the gel: adding the gel aging liquid into the gel pad prepared in the step 4), standing and aging at room temperature to obtain an aged gel pad;
6) solvent exchange: immersing the gel pad aged in the step 5) into n-hexane for 22-26 hours to displace water in the gel to obtain a colloid;
7) surface modification: immersing the colloid prepared in the step 6) into the modified solution, standing for 12-24 hours at room temperature, and finally drying the prepared gel at 90-120 ℃ under normal pressure for 6-8 hours to obtain a hydrophobic silica aerogel pad prepared by taking iron tailings as a raw material;
8) adjusting the pH of the filtrate obtained in the step 2) to 7-8 by using ammonia water under an ultrasonic environment, allowing a large amount of precipitate to appear, standing, filtering, drying filter residue, putting the filter residue into a muffle furnace, and roasting at the temperature of 600-700 ℃ for 1.5-2.5 hours to finally obtain the iron oxide nano powder.
2. The method for simultaneously preparing iron oxide and silica aerogel mats from iron tailings according to claim 1, wherein the components of the iron tailings in step 1) comprise SiO2、CaO、MgO、Al2O3、Fe2O3。
3. The method for simultaneously preparing iron oxide and silica aerogel mats from iron tailings according to claim 1, wherein the hydrochloric acid concentration in step 2) is 1-3mol/L, and the volume ratio of the activated tailings powder to the hydrochloric acid is 1: 1.5-2.1.
4. The method for simultaneously preparing the iron oxide and silica aerogel pad from the iron tailings according to claim 1, wherein the mass ratio of the filter residue to the sodium hydroxide in the step 3) is 1:1.5-2, the iron tailings after the alkali fusion reaction are stirred and reacted at the temperature of 60-90 ℃ according to the solid-to-liquid ratio of 1:3-7, and the crude silicon solution is obtained by filtering.
5. The method for simultaneously preparing the iron oxide and silica aerogel pads from the iron tailings according to claim 1, wherein 2-4mol/L ammonia water solution is added into the crude silicon solution in the step 4) to adjust the pH value, and the gel pads are obtained after the crude silicon solution is uniformly immersed into the glass fiber felt and hardened.
6. The method for simultaneously preparing the iron oxide and silica aerogel pad from the iron tailings according to claim 1, wherein the aging solution in the step 5) is a mixed solution of anhydrous ethanol and ethyl orthosilicate, and the volume ratio of the anhydrous ethanol to the ethyl orthosilicate is 8-12: 1.
7. the method for simultaneously preparing the iron oxide and the silica aerogel pad from the iron tailings according to claim 1, wherein the modification liquid in the step 7) is a mixed liquid of n-hexane and trimethylchlorosilane, and the volume ratio of the n-hexane to the trimethylchlorosilane is 8-12: 1.
8. the process for simultaneously preparing iron oxide and silica aerogel pads from iron tailings according to claim 1, wherein the obtained silica aerogel pad has a density of 0.162 to 0.173g/cm3(ii) a The tap density of the ferric oxide nano powder is 1.063-1.141 g/cm3The particle size is less than 50 nm.
9. The method for simultaneously preparing iron oxide and silica aerogel mats from iron tailings according to claim 1, wherein the hydrochloric acid concentration in step 2) is 2mol/L, and the volume ratio of the activated tailings powder to the hydrochloric acid is 1.6-1.8.
10. The method for simultaneously preparing the iron oxide and the silica aerogel pad from the iron tailings according to claim 1, wherein the modification liquid in the step 7) is a mixed liquid of n-hexane and trimethylchlorosilane, and the volume ratio of the n-hexane to the trimethylchlorosilane is 10: 1.
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CN109503116B (en) * 2018-12-17 2020-12-11 山东鲁阳节能材料股份有限公司 Preparation method of aerogel composite thermal insulation material
CN111534683A (en) * 2020-04-13 2020-08-14 广东工业大学 Method for enriching iron oxide in iron tailings by using alkali fusion method
CN112661193B (en) * 2020-12-18 2022-07-19 河北工业大学 Method for simultaneously preparing binary and ternary high-performance composite aerogel by using iron tailings
CN113817228A (en) * 2021-09-28 2021-12-21 长春工业大学 Modification method of iron-removing tailing slag
CN115709998B (en) * 2022-11-14 2023-03-31 国能龙源环保有限公司 Method for preparing white carbon black by roasting waste wind power blades

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