阅读说明：本技术 一种粉煤灰基磁性分子筛及其制备方法 (Fly ash-based magnetic molecular sieve and preparation method thereof ) 是由 雷畅 龙来寿 郭会时 杨娅妮 付志平 于 2021-03-25 设计创作，主要内容包括：本发明公开一种粉煤灰基磁性分子筛的制备方法,粉煤灰的活化：粉煤灰加入硅源或者铝源,将其进行混合,使得到的混合物中的SiO-2：Al-2O-3比例达到1.0～2.0,在混合物中加入活化剂,混合均匀,并研磨至80-100目后,在高温下活化；活化完成后冷却至室温,研磨至粒径为100目,得到活化熟料；活化熟料和磁性微粒以及蒸馏水以混合搅拌,将混合物密封环境下晶化后,取出冷却、过滤、洗涤、干燥后得到磁性分子筛。本发明通过对粉煤灰进行碱熔活化处理,对粉煤灰的利用程度高,得到的分子筛纯度高,吸附性能好。本发明中,磁性微粒在分子筛的晶化合成过程中嵌入,得到的磁性分子筛磁性效果好,产品性能稳定。(The invention discloses a preparation method of a fly ash-based magnetic molecular sieve, which comprises the following steps of: adding a silicon source or an aluminum source into the fly ash, mixing the fly ash and the silicon source or the aluminum source to obtain SiO in the mixture 2 ：Al 2 O 3 Adding an activating agent into the mixture according to the proportion of 1.0-2.0, uniformly mixing, grinding to 80-100 meshes, and activating at high temperature; cooling to room temperature after activation is finished, and grinding until the particle size is 100 meshes to obtain activated clinker; mixing and stirring the activated clinker, the magnetic particles and distilled water, crystallizing the mixture in a sealed environment, taking out, cooling, filtering and washingAnd drying to obtain the magnetic molecular sieve. The method has the advantages that the alkali fusion activation treatment is carried out on the fly ash, the utilization degree of the fly ash is high, and the obtained molecular sieve has high purity and good adsorption performance. In the invention, the magnetic particles are embedded in the crystallization synthesis process of the molecular sieve, and the obtained magnetic molecular sieve has good magnetic effect and stable product performance.)

1. The preparation method of the fly ash-based magnetic molecular sieve is characterized by comprising the following steps of:

step 1: activation of the fly ash: taking fly ash, simultaneously adding a silicon source or an aluminum source, mixingMixing them to obtain SiO in the mixture₂With Al₂O₃Adding an activating agent into the mixture, uniformly mixing, grinding to 80-100 meshes, and activating at high temperature; cooling to room temperature after activation is finished, and grinding until the particle size is 100 meshes to obtain activated clinker;

step 2: preparing magnetic particles;

and step 3: preparing a magnetic molecular sieve: and (3) mixing and stirring the activated clinker obtained in the step (1), the magnetic particles obtained in the step (2) and distilled water, crystallizing the mixture in a sealed environment after stirring, taking out, cooling, filtering, washing and drying to obtain the magnetic molecular sieve.

2. The method for preparing a magnetic molecular sieve based on fly ash according to claim 1, wherein in the step 1, the silicon source is one or two of silicon dioxide and sodium silicate, and the aluminum source is one or more of sodium aluminate, aluminum oxide and aluminum hydroxide.

3. The method for preparing the fly ash-based magnetic molecular sieve according to claim 1, wherein in the step 1, the activating agent is one or two of sodium hydroxide or sodium carbonate, and the mass ratio of the activating agent to the fly ash silicon-aluminum mixture is 0.8-1.5.

4. The method for preparing the fly ash-based magnetic molecular sieve according to claim 1, wherein in the step 1, the activation temperature is 650-800 ℃, and the activation time is 0.5-2 h.

5. The method for preparing the fly ash-based magnetic molecular sieve according to claim 1, wherein the method for preparing the magnetic particles in the step 2 comprises the following steps: dissolving ferric chloride and sodium acetate in ethylene glycol solution; and heating the solution obtained after dissolution in a sealed environment, taking out, cooling, filtering, washing and drying to obtain the magnetic particles.

6. The method for preparing the fly ash-based magnetic molecular sieve according to claim 5, wherein in the step 2, the mass ratio of the ferric chloride to the sodium acetate is 1:3, and the liquid-solid ratio of the added glycol is 8L/kg.

7. The method for preparing the fly ash-based magnetic molecular sieve according to claim 5, wherein in the step 2, the solution is heated at 200 ℃ for 10 hours;

the preparation method of the magnetic particles comprises the following steps: soluble substances of ferric salt and ferrous salt are dissolved in water, alkali liquor is added, the pH value is adjusted, and the mixture is stirred to form the magnetic particles of ferroferric oxide.

8. The preparation method of the fly ash-based magnetic molecular sieve of claim 1, wherein in the step 3, the mass ratio of the magnetic particles to the activated clinker to the distilled water is 1-3: 10:100, and the stirring time is 24 hours.

9. The method for preparing the fly ash-based magnetic molecular sieve according to claim 1, wherein in the step 3, the crystallization temperature is 100 ℃ and the crystallization time is 6 hours.

10. A fly ash-based magnetic molecular sieve, prepared according to the method of claims 1-9.

Technical Field

The invention belongs to the technical field of molecular sieves, and particularly relates to a preparation method of a fly ash-based magnetic molecular sieve.

Technical Field

The fly ash is a solid waste of modern industries such as power plants, and along with the development of the power industry, the fly ash discharge amount of coal-fired power plants is increased year by year, and the fly ash becomes one of industrial waste residues with larger discharge capacity in China. A large amount of fly ash is piled up, which not only occupies land resources, but also causes dust pollution, erosion and soil pollution, damages ecological balance and causes serious environmental problems. At present, the fly ash is often applied to building materials, mine reclamation materials, mine filling materials and the like. However, the methods have low utilization value of the fly ash, fully develop and utilize fly ash resources, and improve the additional value of the utilization of the fly ash resources, and are problems to be solved urgently in the current high-tech field.

As a porous material, the molecular sieve has a silicon-oxygen tetrahedral structure so that the molecular sieve has a large specific surface area, thereby having high cation exchange capacity and strong adsorption capacity. However, in the conventional molecular sieve synthesis method, sodium metaaluminate and aluminum hydroxide are generally used as an aluminum source, silica and sodium silicate are used as a silicon source, and sodium hydroxide or potassium hydroxide is used as an alkali source, so that the cost is often high.

In the first technical scheme, the molecular sieve is mainly prepared from fly ash as a raw material by a hydrothermal synthesis method, and the main synthesis method comprises the following steps: according to the content of the fly ash raw material, the chemical component proportion in the fly ash is adjusted by adding a silicon-aluminum ingredient; adding the mixed raw materials into a potassium hydroxide solution, and heating and crystallizing at a certain temperature to obtain a molecular sieve crystal; and drying the molecular sieve crystal to obtain the fly ash molecular sieve. Disadvantages 1 of this technique: before the crystallization step of synthesizing the molecular sieve, the fly ash is not activated, so that the molecular sieve synthesized by the fly ash has low purity and poor performance. And (2) disadvantage: the synthesized molecular sieve is not magnetized, so that the difficulty of separation operation can be increased when the synthesized molecular sieve is used for adsorption, and the use cost is increased.

In the second technical scheme, fly ash is mainly used as a raw material, an additive is added, and then the molecular sieve is prepared by a high-temperature roasting and hydrothermal synthesis method, wherein the main synthesis method comprises the following steps: firstly, adding the fly ash into soda ash and aluminum hydroxide for mixing, then roasting at high temperature, carrying out hydrothermal synthesis on roasted slag obtained by roasting, supplementing alkalinity, carrying out crystallization, adding a binder into the obtained molecular sieve crystal powder, and carrying out molding and activation to obtain the molecular sieve. The technology has the disadvantages that the steps for preparing the molecular sieve finished product are relatively complicated, the synthesized molecular sieve is not magnetized, a binder needs to be added, and the cost of the molecular sieve is increased.

In the third technical scheme, fly ash is mainly used as a raw material, and prepared Fe is added in the process of hydro-thermal synthesis of the molecular sieve₃O₄The magnetic material is used for preparing the magnetic zeolite molecular sieve, and the main synthesis method comprises the following steps: firstly, the ferrous chloride and the ferric chloride are utilized to prepare Fe₃O₄Magnetic material, mixing flyash with alkali solution, adding Fe₃O₄And carrying out hydrothermal synthesis on the magnetic material at a certain temperature to prepare the magnetic molecular sieve. The technology has the defects that components in the fly ash are not activated before the step of hydro-thermal synthesis of the molecular sieve, so that the effective components in the fly ash are low, and the synthesized molecular sieve has low purity and poor performance.

Disclosure of Invention

In order to solve the problem that a fine powder product is difficult to separate from a treated liquid in application, the invention adopts a magnetic carrier technology and utilizes fly ash to prepare the magnetic molecular sieve, thereby greatly improving the problem that solid and liquid are difficult to separate in the later period. Compared with the common molecular sieve, the magnetic molecular sieve has the characteristic of being conveniently separated by using a magnetic field, and the powdery product can be directly used in a solvent or a solution without molding. The magnetic zeolite molecular sieve not only can keep excellent adsorption performance, but also has the unique magnetic performance of magnetic particles, and the saturated magnetic adsorbent is separated from an action system through an external magnetic field, so that the operation is simple, the cyclic utilization rate of the adsorbent is greatly improved, and the application value is more remarkable.

The magnetic molecular sieve synthesized by the fly ash is applied to removal and treatment of pollutants, not only accords with the principle of carrying out high-added-value fine utilization on the fly ash, but also effectively solves the pollution problem of the fly ash, changes waste into valuable, is one of the important development directions of the current fly ash pollution treatment, and has obvious application prospect.

The invention provides a preparation method for synthesizing a magnetic molecular sieve by utilizing fly ash. The method can effectively improve the purity of the synthesized molecular sieve by melting and activating the components in the fly ash through high-temperature alkali, thereby improving the adsorption performance of the synthesized molecular sieve; meanwhile, in the process of synthesizing the molecular sieve, the magnetic particles are loaded in the molecular sieve, so that the magnetic property of the molecular sieve is improved, and the separation performance of the molecular sieve is improved.

The specific technical scheme is as follows:

the preparation method of the fly ash-based magnetic molecular sieve is characterized by comprising the following steps of:

step 1: activation of the fly ash: taking fly ash, simultaneously adding a silicon source or an aluminum source, and mixing to obtain SiO in the mixture₂：Al₂O₃Adding an activating agent into the mixture according to the proportion of 1.0-2.0, uniformly mixing, grinding to 80-100 meshes, and activating at high temperature; cooling to room temperature after activation is finished, and grinding until the particle size is 100 meshes to obtain activated clinker;

step 2: preparation of magnetic microparticles: dissolving ferric chloride and sodium acetate in ethylene glycol solution; heating the solution obtained after dissolving in a sealed environment, taking out, cooling, filtering, washing and drying to obtain magnetic particles;

and step 3: preparing a magnetic molecular sieve: and (3) mixing and stirring the activated clinker obtained in the step (1), the magnetic particles obtained in the step (2) and distilled water, crystallizing the mixture in a sealed environment after stirring, taking out, cooling, filtering, washing and drying to obtain the magnetic molecular sieve.

In the step 1, the silicon source is one or two of silicon dioxide and sodium silicate, and the aluminum source is one or more of sodium aluminate, aluminum oxide and aluminum hydroxide.

In the step 1, the activating agent is one or two of sodium hydroxide or sodium carbonate, and the mass ratio of the activating agent to the fly ash silicon-aluminum mixture is 0.8-1.5.

In the step 1, the activation temperature is 650-800 ℃, and the activation time is 0.5-2 h.

In the step 2, the mass ratio of ferric chloride to sodium acetate is 1:3, and the liquid-solid ratio of the added glycol is 8L/kg.

In the step 2, the solution is heated at 200 ℃ for 10 h.

In the step 3, the mass ratio of the magnetic particles to the activated clinker to the distilled water is 1-3: 10:100, and the stirring time is 24 hours.

In the step 3, the crystallization temperature is 100 ℃, and the crystallization time is 6 hours.

The magnetic particles synthesized in step 2 can be synthesized by the following scheme, in addition to the scheme of the present invention: dissolving soluble ferric salt and ferrous salt with proper concentration in water, adding alkali liquor, regulating pH value, stirring at a certain speed for a period of time to form the magnetic particles of ferroferric oxide.

The fly ash is waste residue which takes silicon dioxide and aluminum oxide as main components, and the cheap fly ash is utilized to synthesize the molecular sieve, so that the problem of raw materials for synthesizing the molecular sieve can be solved, and the synthesis cost of the molecular sieve is obviously reduced.

The invention has the advantages that:

the magnetic zeolite molecular sieve synthesized by the technical scheme of the invention has high utilization degree of the fly ash by carrying out alkali fusion activation treatment on the fly ash, and the obtained molecular sieve has high purity and good adsorption performance. In the invention, the magnetic particles are embedded in the crystallization synthesis process of the molecular sieve, and the obtained magnetic molecular sieve has good magnetic effect and stable product performance.

Detailed Description

The specific technical scheme of the invention is described by combining the embodiment.

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.

Example 1

The fly ash is used as a raw material to prepare a fly ash-based magnetic molecular sieve, and the composition of the fly ash is shown in a table 1:

TABLE 1 composition of fly ash

The preparation method of the fly ash-based magnetic molecular sieve comprises the following steps:

step 1: activation of the fly ash: taking 10g of fly ash, adding 3g of sodium aluminate to obtain SiO in the mixture₂With Al₂O₃The molar ratio of (1) to (2) is 1.8, 13g of sodium hydroxide is added, mixed uniformly and ground to 100 meshes. And roasting the mixture in a muffle furnace at the temperature of 700 ℃ for 1h, taking out, cooling to room temperature, and grinding to obtain the activated clinker with the particle size of 100 meshes.

Step 2: preparation of magnetic microparticles: dissolving ferric chloride and sodium acetate in ethylene glycol solution; the mass ratio of ferric chloride to sodium acetate is 1:3, and the liquid-solid ratio of the added glycol is 8L/kg. And heating the solution obtained after dissolution in a sealed reaction kettle at the temperature of 200 ℃ for 10 h. Taking out, cooling, filtering, washing and drying to obtain the magnetic particles.

And step 3: preparing a magnetic molecular sieve: mixing and stirring the activated clinker obtained in the step 1, the magnetic particles obtained in the step 2 and distilled water, wherein the mass ratio of the magnetic particles to the activated clinker to the distilled water is 2:10:100, and the stirring time is 24 hours. And after stirring, sealing the mixture in a reaction kettle at the temperature of 100 ℃ for crystallization for 6 hours, taking out, cooling, filtering, washing and drying to obtain the magnetic molecular sieve.

Example 2

The fly ash is used as a raw material to prepare a fly ash-based magnetic molecular sieve, and the composition of the fly ash is shown in a table 2:

TABLE 2 composition of fly ash

The preparation method of the fly ash-based magnetic molecular sieve comprises the following steps:

step 1: activation of the fly ash: taking 10g of fly ash, adding 4g of sodium aluminate to obtain SiO in the mixture₂With Al₂O₃The molar ratio of (1.8), adding 12g of sodium carbonate, mixing uniformly, and grinding to 100 meshes. And roasting the mixture in a muffle furnace at the temperature of 650 ℃ for 1h, taking out, cooling to room temperature, and grinding to obtain the activated clinker with the particle size of 100 meshes.

Step 2: preparation of magnetic microparticles: 50mL of ferric chloride solution with the concentration of 0.1mol/L and 100mL of ferrous sulfate solution with the concentration of 0.1mol/L are added with 60mL of sodium hydroxide with the concentration of 1mol/L, and stirred for 30 minutes under the protection of nitrogen to form magnetic particles.

And step 3: preparing a magnetic molecular sieve: mixing and stirring the activated clinker obtained in the step 1, the magnetic particles obtained in the step 2 and distilled water, wherein the mass ratio of the magnetic particles to the activated clinker to the distilled water is 1:10:100, and the stirring time is 24 hours. And after stirring, sealing the mixture in a reaction kettle at the temperature of 100 ℃ for crystallization for 6 hours, taking out, cooling, filtering, washing and drying to obtain the magnetic molecular sieve.

The invention has the technical effects that: (1) activation of the fly ash: before the molecular sieve is synthesized, the fly ash is activated by adding an activating agent, so that the utilization efficiency of the fly ash is improved, and the purity of the obtained molecular sieve is higher. (2) Loading of magnetic microparticles: the magnetic particles are added in the synthesis process of the molecular sieve, so that the magnetic particles are better combined in pores of the molecular sieve, and the stability of the magnetic molecular sieve is improved.