阅读说明：本技术 利用电熔α-β氧化铝砖的除尘灰制备莫来石晶须的方法 (Method for preparing mullite whisker from dedusting ash of electric melting alpha-beta alumina brick ) 是由 武杏荣 王丹丹 申星梅 曹发斌 于 2020-12-22 设计创作，主要内容包括：本发明公开了固废利用技术领域的利用电熔α-β氧化铝砖的除尘灰制备莫来石晶须的方法,具体包括以下步骤：(1)将Al-2(SO-4)-3·18H-2O脱去结晶水和吸附水,得到Al-2(SO-4)-3；(2)将Al-2(SO-4)-3和除尘灰按质量比4.699:1混合,得到混合料,向混合料中加入熔盐介质,混合均匀后置于玛瑙研钵中研磨至粉体,随后放入电阻炉中,在900-1100℃下煅烧1-5h,得到煅烧料；(3)煅烧料随炉冷却至室温,并用蒸馏水反复洗涤,过滤后烘干,得到莫来石粉体；本发明与其他传统的莫来石的合成方法相比,该方法的制备过程简单,合成温度较低,降低了莫来石晶须的合成成本,且制得的晶体具有纯度高、分散性好、表面光滑、尺寸均匀等优点,有效地实现了对电熔α-β氧化铝砖的除尘灰的再利用,易于实现工业化生产。(The invention discloses a method for preparing mullite whiskers by using dedusting ash of an electric melting alpha-beta alumina brick in the technical field of solid waste utilization, which specifically comprises the following steps: (1) mixing Al 2 (SO 4 ) 3 ·18H 2 Removing crystal water and adsorbed water from O to obtain Al 2 (SO 4 ) 3 (ii) a (2) Mixing Al 2 (SO 4 ) 3 Mixing the powder with dedusting ash according to a mass ratio of 4.699:1 to obtain a mixture, adding a molten salt medium into the mixture, uniformly mixing, placing the mixture into an agate mortar, grinding the mixture into powder, then placing the powder into a resistance furnace, and calcining the powder for 1 to 5 hours at the temperature of 900-; (3) cooling the calcined material to room temperature along with the furnace, and repeatedly washing the calcined material by using distilled waterFiltering and drying to obtain mullite powder; compared with other traditional mullite synthesis methods, the method has the advantages of simple preparation process, lower synthesis temperature, reduced mullite whisker synthesis cost, high purity of the prepared crystal, good dispersibility, smooth surface, uniform size and the like, effectively realizes the reutilization of the dedusting ash of the electric smelting alpha-beta alumina brick, and is easy to realize industrial production.)

1. The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick is characterized by comprising the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 250-350 ℃ for 2-4h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Mixing Al₂(SO₄)₃Mixing the powder with dedusting ash according to a mass ratio of 4.699:1 to obtain a mixture, adding a molten salt medium into the mixture, uniformly mixing, placing the mixture into an agate mortar, grinding the mixture into powder, then placing the powder into a resistance furnace, and calcining the powder for 1 to 5 hours at the temperature of 900-;

(3) and cooling the calcined material to room temperature along with the furnace, repeatedly washing the calcined material by using distilled water, filtering and drying to obtain the mullite powder.

2. The method for preparing mullite whiskers by using dedusting ash of electric smelting alpha-beta alumina bricks according to claim 1, wherein in the step (1), Al is used₂(SO₄)₃·18H₂O is incubated at 300 ℃ for 3 h.

3. The method for preparing mullite whiskers from fly ash of an electrofused α - β alumina brick as recited in claim 1, wherein in said step (2), the calcination temperature is 1000 ℃ and the calcination time is 3 hours.

4. The method for preparing mullite whiskers from fly ash of an electrofused α - β alumina brick as claimed in claim 1, wherein the molten salt medium is anhydrous sodium sulfate.

5. The method for preparing mullite whiskers by using dedusting ash of electric smelting alpha-beta alumina bricks according to claim 1, wherein the mass ratio of the mixed material to the molten salt medium is 1: (1-1.5) mixing.

6. The method for preparing mullite whiskers from fly ash of an electrofused α - β alumina brick as recited in claim 1, wherein the temperature of said distilled water is 90 ℃.

7. The method for preparing mullite whiskers from fly ash of electrofused α - β alumina bricks as recited in claim 1, wherein in said step (3), said last washing liquid is Ba (NO) (Ba) for said last washing liquid₃)₂No precipitation occurred upon titration of the solution.

8. The method for preparing mullite whiskers from fly ash of an electrofused α - β alumina brick as claimed in claim 1, wherein in said step (3), the drying temperature is 110 ℃ and the drying time is 12 h.

Technical Field

The invention relates to the technical field of solid waste utilization, in particular to a method for preparing mullite whiskers by using dedusting ash of an electric melting alpha-beta alumina brick.

Background

The fly ash is fly ash obtained by treating and collecting air pollutants discharged by industrial enterprises and the like through dust removing equipment such as bag-type dust collectors and the like, and the components of the fly ash are related to collected particulate gas. Depending on the needs and nature of the dust removal arrangement, there are roughly two categories: flue gas dust and environmental dust. The fly ash obtained by collecting fine granular substances generated in the process of sintering and electrically melting alpha-beta alumina bricks belongs to flue gas fly ash, wherein the main component is SiO₂And Al₂O₃The contents of the two are 54.95% and 19.07%, respectively, so that the silicon source can be provided by the fly ash. Under the background of advocating energy conservation and emission reduction and developing circular economy in China, the fly ash is not accumulated to cause resource waste and pollute the environment, so that the fly ash has great significance for effectively utilizing the fly ash.

Mullite is Al₂O₃-SiO₂The unique stable compound in the binary system has lower thermal expansion coefficient and thermal conductivity, good high-temperature creep resistance, higher high-temperature mechanical strength and stable chemical performance, and is a high-temperature structural ceramic material with excellent performance. Mullite (3A 1)₂O₃·2SiO₂) The crystal whisker is a single crystal with an acicular structure, has the excellent characteristics of mullite materials, and has better mechanical property, high temperature resistance, oxidation resistance, thermal shock resistance and other properties than polycrystalline mullite. In addition, the mullite whisker has the characteristics of small thermal expansion coefficient, high-temperature strength, high shear modulus and the like. Therefore, the mullite whisker is used as an excellent toughening reinforcing agent in the ceramic matrix composite material, and the development and the application of the mullite whisker can greatly improve the comprehensive utilization of the ceramic matrix composite material.

The main synthesis method of the traditional mullite whisker comprises a sol-gel method,Al₂O₃-SiO₂Powder calcination, mineral decomposition, oxide doping, in-situ growth, and the like. The preparation of mullite microcrystal by combining sol-gel with microwave hydrothermal method (artificial crystal institute, 2010, 39(6):1456-₃)₃·9H₂O and ethyl orthosilicate are used as main raw materials, a sol-gel combined microwave hydrothermal method is adopted to prepare mullite powder, and the process is complex and not beneficial to industrialization. In "Mullite morphology in refined Kaolinte/halloyite catalysts" ("Materials Science Letters, 1998, 4(10): 1270-. The above synthesis methods have different disadvantages of high reaction temperature, difficult control of synthesis process conditions, high raw material cost, low whisker yield and the like, and as a powder preparation method which is concerned recently, the molten salt system can provide a liquid phase environment for reaction, increase the diffusion coefficient of each reactant, reduce the energy barrier of the reaction system, effectively reduce the reaction temperature and shorten the time required by the reaction, and enable the product to have good micro-morphology compared with other methods. The invention patent (20171003634.7) mentions that the mullite powder is prepared by taking coal gangue and crystalline potassium aluminum sulfate dodecahydrate as raw materials and adopting a molten salt method at a lower temperature (750 ℃ C. and 950 ℃ C.). So far, no relevant report of preparing mullite whisker by using fly ash exists.

Therefore, a method for preparing mullite whiskers by using the dedusting ash of the electric melting alpha-beta alumina brick is provided to solve the problems.

Disclosure of Invention

The invention aims to provide a method for preparing mullite whiskers by using dedusting ash of an electric melting alpha-beta alumina brick so as to solve the problems in the background technology.

In order to achieve the purpose, the invention provides the following scheme to realize the following steps: a method for preparing mullite whiskers by utilizing dedusting ash of an electric smelting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 250-350 ℃ for 2-4h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Mixing Al₂(SO₄)₃Mixing the powder with dedusting ash according to a mass ratio of 4.699:1 to obtain a mixture, adding a molten salt medium into the mixture, uniformly mixing, placing the mixture into an agate mortar, grinding the mixture into powder, then placing the powder into a resistance furnace, and calcining the powder for 1 to 5 hours at the temperature of 900-;

(3) and cooling the calcined material to room temperature along with the furnace, repeatedly washing the calcined material by using distilled water, filtering and drying to obtain the mullite powder.

Preferably, in the step (1), Al₂(SO₄)₃·18H₂O is incubated at 300 ℃ for 3 h.

Preferably, in the step (2), the calcining temperature is 1000 ℃ and the calcining time is 3 h.

Preferably, the molten salt medium is anhydrous sodium sulfate.

Preferably, the mixture and the molten salt medium are mixed according to the mass ratio of 1: (1-1.5) mixing.

Preferably, the temperature of the distilled water is 90 ℃.

Preferably, in the step (3), the last washing solution is Ba (NO)₃)₂No precipitation occurred upon titration of the solution.

Preferably, in the step (3), the drying temperature is 110 ℃ and the drying time is 12 h.

The invention has the beneficial effects that:

the raw material dedusting ash used for providing the silicon source is solid waste generated in the process of sintering the electric melting alpha-beta alumina brick, and the waste resource utilization of the dedusting ash is realized. The invention adopts salt sodium sulfate with low melting point and high solubility as reaction medium, which can not only form eutectic point with aluminum sulfate, but also decompose liquid aluminum sulfate at lower temperature to produce Al₂O₃And provides a suitable environment for the free growth of the mullite, and effectively reduces the temperature for synthesizing the mullite powder;

compared with other traditional mullite synthesis methods, the preparation method adopted by the invention has the advantages that the preparation process is simple, the synthesis temperature is lower, the synthesis cost of the mullite whisker is reduced, the prepared crystal has the advantages of high purity, good dispersibility, smooth surface, uniform size and the like, the reuse of the dedusting ash of the electric smelting alpha-beta alumina brick is effectively realized, and the industrial production is easy to realize;

the product obtained by the method provided by the invention has high purity, does not need acid washing or alkali washing, and does not cause secondary pollution to the environment.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is an X-ray diffraction pattern of mullite prepared in example 1;

FIG. 2 is an X-ray diffraction pattern of mullite prepared in example 2;

FIG. 3 is a transmission electron microscopy spectrum of mullite prepared in example 2;

FIG. 4 is a transmission electron micrograph of mullite prepared in example 2;

FIG. 5 is a transmission electron micrograph of mullite prepared in example 2;

FIG. 6 is an X-ray diffraction pattern of mullite prepared in example 3;

FIG. 7 is an X-ray diffraction pattern of mullite prepared in example 4;

FIG. 8 is an X-ray diffraction pattern of mullite prepared in example 5;

FIG. 9 is an X-ray diffraction pattern of mullite prepared in example 6;

FIG. 10 is an X-ray diffraction pattern of mullite prepared in example 7.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

According to Al₂O₃And SiO₂The mass ratio of the materials is 3:2, and correspondingly Al₂(SO₄)₃And the dedusting ash comprises the following ingredients in percentage by mass: 4.699:1.

Example 1

The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 300 ℃ for 3h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Weighing Al₂(SO₄)₃17.100g and 3.639g of fly ash are mixed to obtain a mixture, 24.887g of molten salt anhydrous sodium sulfate is added into the mixture, the mixture is uniformly mixed and then is put into an agate mortar to be ground into powder, and then the powder is put into a resistance furnace to be calcined for 3 hours at 900 ℃ to obtain a calcined material;

(3) cooling the calcined material to room temperature along with the furnace, and repeatedly washing the calcined material with distilled water at 90 ℃ until the last washing liquid is Ba (NO) used₃)₂And (3) the solution is titrated without precipitation, and then the solution is filtered and then is dried in a 110 ℃ oven for 12 hours to obtain mullite powder.

Example 2

The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 300 ℃ for 3h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Weighing Al₂(SO₄)₃17.100g and 3.639g of fly ash are mixed to obtain a mixture, and 24.8 g of molten salt anhydrous sodium sulfate is added into the mixture87g, uniformly mixing, grinding the mixture in an agate mortar to powder, and then putting the powder in a resistance furnace to calcine the powder for 3 hours at 1000 ℃ to obtain a calcined material;

(3) cooling the calcined material to room temperature along with the furnace, and repeatedly washing the calcined material with distilled water at 90 ℃ until the last washing liquid is Ba (NO) used₃)₂And (3) the solution is titrated without precipitation, and then the solution is filtered and then is dried in a 110 ℃ oven for 12 hours to obtain mullite powder.

Example 3

The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 300 ℃ for 3h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Weighing Al₂(SO₄)₃17.100g and 3.639g of fly ash are mixed to obtain a mixture, 24.887g of molten salt anhydrous sodium sulfate is added into the mixture, the mixture is uniformly mixed and then is put into an agate mortar to be ground into powder, and then the powder is put into a resistance furnace to be calcined for 3 hours at 1100 ℃ to obtain a calcined material;

(3) cooling the calcined material to room temperature along with the furnace, and repeatedly washing the calcined material with distilled water at 90 ℃ until the last washing liquid is Ba (NO) used₃)₂And (3) the solution is titrated without precipitation, and then the solution is filtered and then is dried in a 110 ℃ oven for 12 hours to obtain mullite powder.

Example 4

The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 300 ℃ for 3h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Weighing Al₂(SO₄)₃17.100g and 3.639g of fly ash are mixed to obtain a mixture, 20.739g of molten salt anhydrous sodium sulfate is added into the mixture, the mixture is uniformly mixed and then put into an agate mortar to be ground into powder, and then the powder is put into a resistance furnace to be calcined at 1000 DEG CCalcining for 3 hours to obtain a calcined material;

(3) cooling the calcined material to room temperature along with the furnace, and repeatedly washing the calcined material with distilled water at 90 ℃ until the last washing liquid is Ba (NO) used₃)₂And (3) the solution is titrated without precipitation, and then the solution is filtered and then is dried in a 110 ℃ oven for 12 hours to obtain mullite powder.

Example 5

The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 300 ℃ for 3h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Weighing Al₂(SO₄)₃17.100g and 3.639g of fly ash are mixed to obtain a mixture, 31.109g of molten salt anhydrous sodium sulfate is added into the mixture, the mixture is uniformly mixed and then is put into an agate mortar to be ground into powder, and then the powder is put into a resistance furnace to be calcined for 3 hours at 1000 ℃ to obtain a calcined material;

(3) cooling the calcined material to room temperature along with the furnace, and repeatedly washing the calcined material with distilled water at 90 ℃ until the last washing liquid is Ba (NO) used₃)₂And (3) the solution is titrated without precipitation, and then the solution is filtered and then is dried in a 110 ℃ oven for 12 hours to obtain mullite powder.

Example 6

The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 300 ℃ for 3h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Weighing Al₂(SO₄)₃17.100g and 3.639g of fly ash are mixed to obtain a mixture, 24.887g of molten salt anhydrous sodium sulfate is added into the mixture, the mixture is uniformly mixed and then is put into an agate mortar to be ground into powder, and then the powder is put into a resistance furnace to be calcined for 1h at 1000 ℃ to obtain a calcined material;

(3) the calcined material is cooled to room temperature along with the furnace and is usedRepeatedly washing with 90 deg.C distilled water until the last washing solution is Ba (NO)₃)₂And (3) the solution is titrated without precipitation, and then the solution is filtered and then is dried in a 110 ℃ oven for 12 hours to obtain mullite powder.

Example 7

The method for preparing the mullite whiskers by using the fly ash of the electric melting alpha-beta alumina brick comprises the following steps:

(1) mixing Al₂(SO₄)₃·18H₂Keeping the temperature of O at 300 ℃ for 3h to remove crystal water and absorbed water to obtain Al₂(SO₄)₃；

(2) Weighing Al₂(SO₄)₃17.100g and 3.639g of fly ash are mixed to obtain a mixture, 24.887g of molten salt anhydrous sodium sulfate is added into the mixture, the mixture is uniformly mixed and then is put into an agate mortar to be ground into powder, and then the powder is put into a resistance furnace to be calcined for 5 hours at 1000 ℃ to obtain a calcined material;

(3) cooling the calcined material to room temperature along with the furnace, and repeatedly washing the calcined material with distilled water at 90 ℃ until the last washing liquid is Ba (NO) used₃)₂And (3) the solution is titrated without precipitation, and then the solution is filtered and then is dried in a 110 ℃ oven for 12 hours to obtain mullite powder.

In summary, the embodiments of the present invention have the following beneficial effects that, in embodiments 1 to 7 of the present invention, the mullite whisker is prepared by using the fly ash of the fused α - β alumina brick, so that the waste resource utilization of the fly ash is realized, and the preparation process is simple, the production conditions are easy to control, the cost is lower compared with the traditional synthesis method, and the industrial production is easy to realize.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not exhaustive. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.