1. A preparation method for synthesizing a pure-phase P-type molecular sieve by using an activated fly ash silicon-aluminum insoluble phase is characterized in that the pure-phase P-type molecular sieve is synthesized by using solid waste fly ash generated by a coal-fired power plant as a raw material, activating the fly ash silicon-aluminum insoluble phase by wet grinding and adjusting the solid-liquid ratio for crystallization; the preparation method comprises the steps of raw material mixing, wet grinding, solid-liquid ratio adjustment, crystallization, suction filtration washing and drying.

2. The preparation method of the activated fly ash silicon-aluminum insoluble phase synthesis pure-phase P-type molecular sieve according to claim 1, characterized in that the P-type molecular sieve is prepared by a wet grinding activation method and a hydrothermal crystallization process synthesis method by utilizing fly ash, diatomite, sodium hydroxide and deionized water, and the wet grinding-hydrothermal method has the characteristics of high activation efficiency and low energy consumption; the P-type molecular sieve is pure phase, high in crystallinity, low in synthesis energy consumption, and excellent in adsorptivity and stability.

3. The method for preparing the pure-phase P-type molecular sieve by synthesizing the activated fly ash silicon-aluminum insoluble phase according to claim 1, which is characterized by comprising the following steps of,

(1) mixing raw materials: mixing fly ash, diatomite and sodium hydroxide according to a specific proportion, wherein the fly ash is sieved by a 100-mesh sieve;

(2) wet grinding: adding a certain amount of deionized water into the solid mixed in the step (1), wherein the solid-liquid ratio is 1:1-1:5, the grinding time is 30-150min, the rotating speed is 300-;

(3) adjusting the solid-liquid ratio: taking out the mixture subjected to wet grinding activation in the step (2), and adding a certain amount of deionized water to adjust the solid-liquid ratio;

(4) and (3) crystallization: placing the silicon-aluminum gel liquid obtained in the step (3) into a hydrothermal reaction kettle, and placing the reaction kettle into a constant-temperature drying box for heat preservation;

(5) and (3) suction filtration and washing: cooling the silicon-aluminum gel liquid obtained in the step (4) to room temperature, carrying out suction filtration to obtain a solid residue, and washing the residue with deionized water for 2-3 times to obtain a P-type molecular sieve;

(6) and (4) taking out the P-type molecular sieve obtained in the step (5), and drying in a drying oven at the constant temperature of 75-85 ℃ for 20-28h to obtain the P-type molecular sieve.

4. The method for preparing the pure-phase P-type molecular sieve by the silicon-aluminum insoluble phase synthesis of the activated fly ash according to claim 3, wherein the mass ratio of the fly ash, the diatomite and the NaOH in the step (1) is m (FA) to m (DE) to m (NaOH) is 5:3: 7.6.

5. The preparation method of the activated fly ash silicon-aluminum insoluble phase synthesized pure-phase P-type molecular sieve as claimed in claim 3, wherein the grinding tank and the grinding balls in the step (2) are made of zirconia, the diameters of the grinding balls are 10mm, 6mm and 3mm, and the mass ratio is 5:3: 2; in the wet grinding processThe solid-liquid ratio is m (FA + DE + NaOH): V (H)₂O) is 1:1/1:2/1:3/1:4/1:5, the grinding time is 30-150min, the rotating speed is 300-.

6. The preparation method of the activated fly ash silicon-aluminum insoluble phase synthesized pure-phase P-type molecular sieve according to claim 3, wherein deionized water is added in the step (3) to adjust the solid-to-liquid ratio to be 1: 2-1: 6.

7. The method for preparing the pure-phase P-type molecular sieve from the activated fly ash silicon-aluminum insoluble phase as claimed in claim 3, wherein the step (4) is performed by direct crystallization without aging, wherein the drying temperature is 100-180 ℃ and the drying time is 12-60 h.

Background

At present, fly ash is the main solid waste generated by coal-fired power plants, and 50-200 kg of fly ash is generated when 1 ton of coal is consumed. China mainly focuses on thermal power generation, and generates more than 7 hundred million tons of fly ash every year, and the comprehensive utilization rate of the fly ash is 70 percent. The piled fly ash not only occupies land resources, but also brings environmental pollution risks. Through many years of research, a relatively perfect molecular sieve synthesis process is formed at present. However, since the silicon and aluminum in the fly ash generated after the coal is burned at high temperature mainly exist as quartz and mullite insoluble phases, the activation of the insoluble phases in the fly ash is always the focus of research. In order to improve the activation rate of the insoluble phase of the fly ash, researchers develop a high-temperature alkali fusion method, a microwave alkali fusion method, an ultrasonic alkali fusion method, a molten salt method and the like on the basis of the traditional alkali fusion. These studies lay the foundation for the activation of the silica-alumina insoluble phase of the fly ash. However, the method for activating the insoluble phase in the fly ash under the condition of low energy consumption is not innovative and the crystallinity of the synthesized molecular sieve is not high, so that the energy consumption of the synthesis process is reduced and the crystallinity of the synthesized molecular sieve is improved by using the wet grinding activated fly ash silicon-aluminum insoluble phase.

Disclosure of Invention

The invention aims to provide a preparation method for synthesizing a pure-phase P-type molecular sieve by using an activated fly ash silicon-aluminum insoluble phase, which solves the problems of high energy consumption and low relative crystallinity in the process of synthesizing the molecular sieve.

In order to solve the problems, the invention adopts the following technical scheme:

a preparation method for synthesizing a pure-phase P-type molecular sieve by using an activated fly ash silicon-aluminum insoluble phase is characterized in that a solid waste fly ash generated by a coal-fired power plant is used as a raw material, and a pure-phase P-type molecular sieve product is synthesized by wet grinding and activation; the preparation method comprises the steps of raw material mixing, wet grinding, solid-liquid ratio adjustment, crystallization, suction filtration washing and drying.

Furthermore, the P-type molecular sieve is prepared by a synthesis method of wet grinding and activation by utilizing fly ash, diatomite, sodium hydroxide and deionized water and then hydrothermal crystallization process, and the wet grinding-hydrothermal method has the characteristics of high activation efficiency and low energy consumption. The P-type molecular sieve is pure phase, high in crystallinity, low in synthesis energy consumption, and excellent in adsorptivity and stability.

The preparation method for synthesizing the pure-phase P-type molecular sieve by using the activated fly ash silicon-aluminum insoluble phase specifically comprises the following steps,

(1) mixing raw materials: mixing Fly Ash (FA), Diatomite (DE) and sodium hydroxide according to a specific proportion, wherein the fly ash is sieved by a 100-mesh sieve.

(2) Wet grinding: adding a certain amount of deionized water into the solid mixed in the step (1), wherein the solid-liquid ratio is 1:1-1:5, the grinding time is 30-150min, the rotating speed is 300-;

(3) adjusting the solid-liquid ratio: taking out the mixture subjected to wet grinding activation in the step (2), and adding a certain amount of deionized water to adjust the solid-liquid ratio;

(4) and (3) crystallization: placing the silicon-aluminum gel liquid obtained in the step (3) into a hydrothermal reaction kettle, and placing the reaction kettle into a constant-temperature drying box for crystallization, drying and heat preservation;

(5) and (3) suction filtration and washing: cooling the silicon-aluminum gel liquid obtained in the step (4) to room temperature, carrying out suction filtration to obtain a solid residue, and washing the residue with deionized water for 2-3 times to obtain a P-type molecular sieve;

(6) and (4) taking out the P-type molecular sieve obtained in the step (5), and drying in a constant-temperature drying oven at 80 ℃ for 24h to obtain the P-type molecular sieve.

Further, in the step (1), the mass ratio of the fly ash, the diatomite and the NaOH is m (FA) to m (DE) to m (NaOH) 5:3:7.6 (the ratio is determined according to the molecular formula of the P-type molecular sieve).

Further, the grinding tank and the grinding balls in the step (2) are made of zirconia, the diameters of the grinding balls are 10mm, 6mm and 3mm, and the mass ratio is 5:3: 2; the solid-to-liquid ratio in the wet grinding process is

m(FA+DE+NaOH):V(H₂O) is 1:1/1:2/1:3/1:4/1:5, the grinding time is 30-150min, the rotating speed is 300-.

Further, deionized water is added in the step (3) to adjust the solid-to-liquid ratio to be 1: 2-1: 6.

Furthermore, the step (4) is directly crystallized without aging, wherein the crystallization drying temperature is 100-180 ℃, and the crystallization drying time is 12-60 h.

Compared with the prior art, the invention has the beneficial technical effects that: the invention utilizes solid waste fly ash generated by a coal-fired power plant to reduce the particle size D90 of a raw material by 103nm through wet grinding and activation, and the nuclear magnetic resonance analysis (²⁹Si MAS-NMR) raw material Q⁴Disappeared in 90min of Wet milling, Q³The content is minimum at 120min, Q⁰、Q¹And Q²The sum of the contents reaches the maximum, and the wet grinding activation of the process cooperates with NaOH to well break the high-polymerization aluminosilicate into short-chain low-polymerization aluminosilicate. The wet-milling sample is not needed to be aged for synthesizing the P-type molecular sieve, the optimal synthesis condition is that the crystallization temperature is 160 ℃, the crystallization time is 48 hours, the solid-liquid ratio is 1:5, the relative crystallinity of the synthesized P-type molecular sieve is 89.37 percent, and the relative purity is 93.54 percent. The method uses a wet grinding process for reducing energy consumption, combines a hydrothermal crystallization process, synthesizes the pure-phase high-crystallinity P-type molecular sieve, has wide application, is a friendly adsorbent, and can realize the efficient utilization of solid waste resources with low energy consumption.

Drawings

The invention is further illustrated in the following description with reference to the drawings.

FIG. 1 is a flow chart of the process of example 2 of the present invention.

Detailed Description

The following detailed description of the preferred embodiments of the present invention is provided to enable those skilled in the art to more readily understand the advantages and features of the present invention and to thereby define the scope of the invention more clearly.

Example 1

A method for preparing a pure-phase P-type molecular sieve by synthesizing green activated fly ash from a silicon-aluminum insoluble phase is characterized by comprising the following steps,

(1) mixing raw materials: mixing the fly ash, the diatomite and the NaOH according to a specific mass ratio of 5:3:7.6, wherein the fly ash is sieved by a 100-mesh sieve.

(2) Wet grinding: adding a certain amount of deionized water into the solid mixed in the step (1), wherein the solid-liquid ratio is 1:2, the grinding time is 150min, the rotating speed is 600rpm, and the ball powder ratio is 15:1, so as to obtain an activated product;

(3) adjusting the solid-liquid ratio: taking out the mixture subjected to wet grinding activation in the step (2), and adding a certain amount of deionized water to adjust the solid-liquid ratio to be 1:5, namely adding deionized water with the same mass as the mixture;

(4) and (3) crystallization: placing the silicon-aluminum gel liquid obtained in the step (3) into a hydrothermal reaction kettle, and placing the reaction kettle into a constant-temperature drying box at 160 ℃ for heat preservation for 48 hours;

(5) and (3) suction filtration and washing: cooling the silicon-aluminum gel liquid obtained in the step (4) to room temperature, carrying out suction filtration to obtain a solid residue, and washing the residue for 3 times by using deionized water to obtain a P-type molecular sieve;

(6) and (4) taking out the P-type molecular sieve obtained in the step (5), and drying in a constant-temperature drying oven at 80 ℃ for 24h to obtain the P-type molecular sieve.

Example 2

A method for preparing a pure-phase P-type molecular sieve by synthesizing green activated fly ash from a silicon-aluminum insoluble phase is characterized by comprising the following steps,

(1) mixing raw materials: mixing the fly ash, the diatomite and the NaOH according to a specific mass ratio of 5:3:7.6, wherein the fly ash is sieved by a 100-mesh sieve.

(2) Wet grinding: adding a certain amount of deionized water into the solid mixed in the step (1), wherein the solid-liquid ratio is 1:2, the grinding time is 120min, the rotating speed is 670rpm, and the ball powder ratio is 15:1, so as to obtain an activated product;

(3) adjusting the solid-liquid ratio: taking out the mixture subjected to wet grinding activation in the step (2), and adding a certain amount of deionized water to adjust the solid-liquid ratio to be 1:5, namely adding deionized water with the same mass as the mixture;

(4) and (3) crystallization: placing the silicon-aluminum gel liquid obtained in the step (3) into a hydrothermal reaction kettle, and placing the reaction kettle into a constant-temperature drying box at 160 ℃ for heat preservation for 48 hours;

(5) and (3) suction filtration and washing: cooling the silicon-aluminum gel liquid obtained in the step (4) to room temperature, carrying out suction filtration to obtain a solid residue, and washing the residue for 3 times by using deionized water to obtain a P-type molecular sieve;

(6) and (4) taking out the P-type molecular sieve obtained in the step (5), and drying in a constant-temperature drying oven at 80 ℃ for 24h to obtain the P-type molecular sieve.

Example 3

A method for preparing a pure-phase P-type molecular sieve by synthesizing green activated fly ash from a silicon-aluminum insoluble phase is characterized by comprising the following steps,

(1) mixing raw materials: mixing the fly ash, the diatomite and the NaOH according to a specific mass ratio of 5:3:7.6, wherein the fly ash is sieved by a 100-mesh sieve.

(2) Wet grinding: adding a certain amount of deionized water into the solid mixed in the step (1), wherein the solid-liquid ratio is 1:2, the grinding time is 120min, the rotating speed is 600rpm, and the ball powder ratio is 20:1, so as to obtain an activated product;

(3) adjusting the solid-liquid ratio: taking out the mixture subjected to wet grinding activation in the step (2), and adding a certain amount of deionized water to adjust the solid-liquid ratio to be 1: 5;

(4) and (3) crystallization: placing the silicon-aluminum gel liquid obtained in the step (3) into a hydrothermal reaction kettle, and placing the reaction kettle into a constant-temperature drying box at 160 ℃ for heat preservation for 48 hours;

(5) and (3) suction filtration and washing: cooling the silicon-aluminum gel liquid obtained in the step (4) to room temperature, carrying out suction filtration to obtain a solid residue, and washing the residue for 3 times by using deionized water to obtain a P-type molecular sieve;

(6) and (4) taking out the P-type molecular sieve obtained in the step (5), and drying in a constant-temperature drying oven at 80 ℃ for 24h to obtain the P-type molecular sieve.

Example 4

A method for preparing a pure-phase P-type molecular sieve by synthesizing green activated fly ash from a silicon-aluminum insoluble phase is characterized by comprising the following steps,

(1) mixing raw materials: mixing the fly ash, the diatomite and the NaOH according to a specific mass ratio of 5:3:7.6, wherein the fly ash is sieved by a 100-mesh sieve.

(2) Wet grinding: adding a certain amount of deionized water into the solid mixed in the step (1), wherein the solid-liquid ratio is 1:2, the grinding time is 120min, the rotating speed is 600rpm, and the ball powder ratio is 15:1, so as to obtain an activated product;

(3) adjusting the solid-liquid ratio: taking out the mixture subjected to wet grinding activation in the step (2), and adding a certain amount of deionized water to adjust the solid-liquid ratio to be 1:5, namely adding deionized water with the same mass as the mixture;

(4) and (3) crystallization: placing the silicon-aluminum gel liquid obtained in the step (3) into a hydrothermal reaction kettle, and placing the reaction kettle into a constant-temperature drying box at 160 ℃ for heat preservation for 48 hours;

(5) and (3) suction filtration and washing: cooling the silicon-aluminum gel liquid obtained in the step (4) to room temperature, carrying out suction filtration to obtain a solid residue, and washing the residue for 3 times by using deionized water to obtain a P-type molecular sieve;

(6) and (4) taking out the P-type molecular sieve obtained in the step (5), and drying in a constant-temperature drying oven at 80 ℃ for 24h to obtain the P-type molecular sieve.

Example 5

A method for preparing a pure-phase P-type molecular sieve by synthesizing green activated fly ash from a silicon-aluminum insoluble phase is characterized by comprising the following steps,

(1) mixing raw materials: mixing the fly ash, the diatomite and the NaOH according to a specific mass ratio of 5:3:7.6, wherein the fly ash is sieved by a 100-mesh sieve.

(2) Wet grinding: adding a certain amount of deionized water into the solid mixed in the step (1), wherein the solid-liquid ratio is 1:2, the grinding time is 120min, the rotating speed is 600rpm, and the ball powder ratio is 15:1, so as to obtain an activated product;

(3) adjusting the solid-liquid ratio: taking out the mixture subjected to wet grinding activation in the step (2), and adding a certain amount of deionized water to adjust the solid-liquid ratio to be 1:4, namely adding deionized water with the same mass as the mixture;

(4) and (3) crystallization: placing the silicon-aluminum gel liquid obtained in the step (3) into a hydrothermal reaction kettle, and placing the reaction kettle into a constant-temperature drying box at 160 ℃ for heat preservation for 48 hours;

(5) and (3) suction filtration and washing: cooling the silicon-aluminum gel liquid obtained in the step (4) to room temperature, carrying out suction filtration to obtain a solid residue, and washing the residue for 3 times by using deionized water to obtain a P-type molecular sieve;

(6) and (4) taking out the P-type molecular sieve obtained in the step (5), and drying in a constant-temperature drying oven at 80 ℃ for 24h to obtain the P-type molecular sieve.

Using the P-type molecular sieve prepared in example 4 as an example, the particle size analysis of the wet-milled activated product showed that D90 was 103nm, and the sample was analyzed²⁹Si MAS-NMR analysis can determine Q in the starting material⁴Disappeared in 90min of Wet milling, Q³The content is minimum at 120min, Q⁰、Q¹And Q²The sum of the contents reaches the maximum, and the wet grinding activation of the process cooperates with NaOH to well break the high-polymerization aluminosilicate into short-chain low-polymerization aluminosilicate. Relative crystallinity was calculated to be 89.37% and relative purity to be 93.54% using both Jade and Origin.

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.