CN112427011A

CN112427011A - High-ash soil-made small-pore CHA and MER zeolite

Info

Publication number: CN112427011A
Application number: CN202010194237.3A
Authority: CN
Inventors: 龙英才; 李瀚文; 濮鹏翔; 曹宇凡
Original assignee: Fuyu Zhangjiagang New Material Technology Co ltd
Current assignee: Fuyu Zhangjiagang New Material Technology Co ltd
Priority date: 2020-03-19
Filing date: 2020-03-19
Publication date: 2021-03-02
Anticipated expiration: 2040-03-19
Also published as: CN112427011B

Abstract

The invention provides a high-ash soil-made small-pore CHA and MER zeolite, which comprises the following components: the method comprises the steps of taking metakaolin mineral powder as a first raw material, roasting at high temperature to obtain amorphous powder, adding a proper amount of CHA seed crystals into the amorphous powder, and synthesizing K-CHA and K-MER zeolites through hydrothermal reaction in KOH aqueous solution. The (Na, K) -CHA and (Na, K) -MER zeolites prepared by exchanging the K-CHA and K-MER zeolites with NaCl solution show the ion exchange and adsorption properties of small pore zeolites. The (Na, K) -CHA zeolite and (Na, K) -MER zeolite of the invention can be used for preparing ion exchangers and small molecules, such as CO₂And CH₄CO and H in enriched and waste gas₂S、HCN、COS、NH₃And adsorbing, separating and removing toxic and harmful gases such as NOx. The preparation method adopted by the invention has the advantages of low raw material price, simple synthesis process, no environmental pollution and easy industrialization.

Description

High-ash soil-made small-pore CHA and MER zeolite

Technical Field

The invention relates to the technical field of zeolite molecular sieves, in particular to a high-ash soil-made small-pore CHA and MER zeolite.

Background

The CHA structure type zeolite was previously found in natural minerals, commonly known as chabazite. SiO (silicon dioxide)₂/Al₂O₃The Ca-type chabazite with a molar ratio (SAR) of 4 is limited in its application due to its low natural material reserves, high impurities, too low SAR and low heat stability, and is generally only suitable for use in the preparation of adsorbents and cation exchangers.

The structure of small pore opening and large cavity makes the low-silicon CHA zeolite molecular sieve adsorbent have outstanding application prospect in the aspects of gas adsorption separation and purification. For example, the zeolite adsorbent has a particularly strong selective adsorption of CO₂Selectivity to CH of₄And N₂Respectively is CO₂/CH₄24-51 and CO₂/N₂127-one 135, can be applied to the removal of CO from natural gas and oil field gas₂And H₂S, recovering methane and ethane. In the industrial equipment for preparing oxygen by liquefying air, the 13X zeolite adsorbent is replaced by the pressure swing adsorption of the CHA zeolite adsorbent, so that water and carbon dioxide molecules in the air can be separated and removed with high efficiency and low energy consumption.

The framework and channel opening structure of CHA zeolite molecular sieve are schematically shown in figure 1 and figure 2, and the framework of CHA zeolite molecular sieve is formed from [ SiO ]₄]And [ AlO ]₄]The tetrahedral oxygen sharing chain is connected into a four-oxygen-membered ring and a six-oxygen-membered ring primary structure d6r cage and a four-oxygen-membered ring eight-oxygen-membered ring constructed cha cage, the d6r cage and the cha cage are mutually connected and further orderly connected to form a channel structure with an opening aperture of 0.38x0.38nm, and the cavity of the cha cage is very large and reaches 0.84 x0.84x0.82nm.

The CHA zeolite molecular sieve adsorbent can remove a small amount of CO contained in coking gas₂CO, and CH₄Producing high purity H₂. Another important application of low-silicon CHA zeolites is the adsorptive removal of small molecules of toxic, harmful, malodorous gases from air. Table 1 lists several typical gas names, chemical formulas and molecular dimensions. The pore size of the framework structure of the low-silicon CHA zeolite molecular sieve is 0.36 multiplied by 0.36nm, which is close to the molecular size of the listed toxic, harmful and malodorous gases, and the effective adsorption can be realized by changing the adsorption temperature and pressure. Additionally the silica-alumina of low-silicon CHA zeoliteThe molar ratio is about 4, the molecular sieve adsorbent is more than the cation with balanced framework, different cation type CHA zeolite molecular sieve adsorbents can be prepared by exchanging metal cations with different diameters, and the adsorption pore diameter of the molecular sieve adsorbent is finely adjusted, so that the adsorption selectivity to specific molecules is improved.

TABLE 1

Name of molecule	Chemical formula (II)	Molecular size/nm
			Formaldehyde (I)	CH₃CHO	0.33
Hydrogen sulfide	H₂S	0.36
			Methyl cyanide	CH₃CN	0.42
Hydrogen cyanide	HCN	0.33
			Sulfur dioxide	SO₂	0.36
Carbon monoxide	CO	0.37
			Carbon dioxide	CO₂	0.37
Ammonia	NH₃	0.38

The early MER zeolite is prepared by using alumina as an aluminum source and silica sol as a silicon source and carrying out hydrothermal synthesis in a KOH solution at 150 ℃ for 48 hours. NH is added into a potassium aluminosilicate system taking aluminum hydroxide as an aluminum source₄Cl or KF, and the low-silicon CHA and MER zeolite single crystals with the size of 20-30 microns can be synthesized by hydrothermal reaction at 160 ℃ for 48-120 h. The high crystallinity MER zeolite can also be synthesized by hydrothermal crystal transformation at 150 ℃ in KOH solution by using Y zeolite as a silica-alumina source, and the synthesis of MER zeolite by using minerals as the silica-alumina source is a method of interest in the industry. For example, the SiO is extracted from the stone containing the proteolitic silica by dissolving the stone with alkali₂And mixing the generated silicate with aluminum hydroxide and potassium hydroxide solution for hydrothermal reaction to synthesize the MER zeolite. Grinding schist stripped from coal mining, adding glass and silica powder, adjusting to proper Si/Al molar ratio, and adding Na₂CO₃After mixing, melting at 1000 ℃, quenching and dissolving with water to prepare a basic solution. The solution is added with mixed liquid generated by sodium hydroxide-potassium hydroxide-tetramethylammonium hydroxide-tetrapropylammonium hydroxide-quinlin and the like to carry out hydrothermal reaction in a pressure-resistant reaction kettle at 100 ℃ or 200 ℃ in tetrafluoro to obtain MFI, LTL, ERI-OFF, CHA, MER, GIS, ANA, CAN, SOD and other zeolites with up to 10 different structures. In addition, MER zeolite can also be synthesized by using rice hull ash as a silicon and aluminum raw material and tetraethyl ammonium hydroxide as a template group.

The framework and channel opening structure of MER zeolite molecular sieve is schematically shown in FIG. 3And FIG. 4, the framework structure of MER zeolite crystals is composed of [ SiO ]₄]And [ AlO ]₄]The tetrahedron oxygen sharing chain is connected into a double eight-oxygen ring primary structure MER cage, and further orderly connected into a three-dimensional channel structure with the opening pore diameter of 0.31x0.35, 0.27x0.36, 0.51x0.34 and 0.33x 0.33nm. The zeolite is named Merlinoite, artificially synthesized Linde-W, Zeolite-W, K-W and the like. The reports on the zeolite at home and abroad are relatively few, and recently, the document J.A.C.S,2019,141P12744-12759 reports that MER zeolite adsorbs CO₂It shows a threshold opening and breathing effect which makes it possible to use it for the production of pure methane or pure carbon dioxide. MER zeolites exhibit 100% methanol conversion and dimethyl ether selectivity, as well as high catalytic activity stability in catalytic methanol dehydration reactions.

Disclosure of Invention

In this summary, a series of concepts in a simplified form are introduced that are further described in detail in the detailed description section. This summary of the invention is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

To at least partially solve the above technical problems, the present invention provides a high-ash pore-made small-pore CHA and MER zeolite comprising: firstly, roasting the raw ore powder. The mineral powder is prepared by selecting kaolin mineral powder with the fineness of 320 meshes, roasting the kaolin mineral powder at 650-800 ℃ for 0.5-3 h to collapse the original crystal structure, wherein the crystal structure of metakaolin is amorphous.

Second, CHA and MER synthesis procedures. The raw material, 1mol/L or 2mol/L KOH solution and 5% CHA crystal seeds of the raw material mineral powder are uniformly mixed to form a reaction mixture, the reaction mixture is placed in a stainless steel pressure-resistant counter-pressure kettle and then is placed in an oven to be heated for hydrothermal reaction, the hydrothermal reaction temperature is 130-150 ℃, and the time is 48 hours. And filtering, washing and drying the finally synthesized product to prepare the K-CHA zeolite. And similarly, uniformly mixing the raw material, 2mol/L KOH solution and 5% CHA crystal seeds of the raw material mineral powder to form a reaction mixture, placing the reaction mixture into a stainless steel pressure-resistant counter-pressure kettle, and then placing the reaction mixture into an oven to heat for hydrothermal reaction at the temperature of 130-150 ℃ for 48 hours. And filtering, washing and drying the finally synthesized product to obtain the K-MER zeolite.

Finally, cation exchange is carried out. And (Na, K) -CHA and (Na, K) -MER cationic zeolites are obtained by performing cation exchange on the K-CHA and K-MER zeolites by taking a 0.5N NaCl solution as an ion exchange solution.

Further, the weight ratio of the CHA seed crystal to the amorphous metakaolin mineral powder is 1-10: 50-500.

Further, the temperature of the exchange was 95 ℃ for 2 h. The K-CHA and K-MER zeolites: the NaCl solution is 1:10, the exchange times are 3 times, deionized water is used for washing 3 times after each exchange, and the filter cake after suction filtration can be subjected to next ion exchange.

Further, the concentration of the KOH solution is not limited to 1.0-2.0Mol/L, the solid-to-liquid ratio of the metakaolin mineral powder to the KOH solution is not limited to 1:9, and the percentage of the metakaolin mineral powder added with an appropriate amount of CHA seed crystals is not limited to 5%. The temperature of the hydrothermal reaction is not limited to 130-150 ℃, and the reaction time is not limited to 24-48 h.

Further, the cationic zeolites (Na, K) -CHA, and (Na, K) -MER can be applied to CO₂And CH₄CO and H in enriched and waste gas₂S、HCN、COS、NH₃And NOx and other toxic and harmful gases are adsorbed, separated and removed, and the ion exchange and adsorption properties are realized.

Further, the BET surface area of the CHA zeolite is 12.4cm²G, micropore area 0cm²The volume of the pores is 0.07ml/g, and the volume of the micropores is 0 ml/g. BET surface area of the MER zeolite was 12.4cm²G, micropore area 0cm²(ii)/g, total pore volume 0.04ml/g, micropore volume 0 ml/g. BET surface area of the cationic (Na, K) -CAH zeolite is 103.3cm²G, micropore area 62.0cm²(ii) a total pore volume of 0.128ml/g and a micropore volume of 0.025 ml/g. BET surface area of the cationic (Na, K) -MER zeolite was 20.8cm²G, micropore area 0cm²(ii)/g, total pore volume 0.06ml/g, micropore volume 0 ml/g. Show theCHA and MER zeolites have rich intergranular pores, the adsorption characteristics of small micropores.

Compared with the prior art, the invention has the technical effects that: the invention provides a high-ash soil-made small-pore CHA and MER zeolite which takes metakaolin mineral powder as a first raw material, and the raw material has rich storage capacity and low price in Mongolian western areas in China. After the raw material is roasted to remove the adsorption and crystallization water, the framework is completely destroyed to become amorphous powder, a proper amount of CHA seed crystals are added into the amorphous powder, K-CHA and K-MER zeolites are synthesized by hydrothermal reaction in KOH aqueous solution, and the (Na, K) -CHA and (Na, K) -MER zeolites prepared by NaCl solution exchange of the K-CHA and K-MER zeolites show the ion exchange and adsorption properties of small-pore zeolites. The (Na, K) -CHA zeolite and (Na, K) -MER zeolite of the invention can be used for preparing ion exchangers and small molecules, such as CO₂And CH₄CO and H in enriched and waste gas₂S、HCN、COS、NH₃And adsorbing, separating and removing toxic and harmful gases such as NOx. Meanwhile, the preparation method adopted by the invention has the advantages of low raw material price, simple synthesis process, no environmental pollution and easy industrialization.

Drawings

In order that the advantages of the invention will be readily understood, a more particular description of the invention briefly described above will be rendered by reference to specific embodiments that are illustrated in the appended drawings. Understanding that these drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings.

FIG. 1 is a schematic representation of the framework structure of the CHA zeolitic molecular sieve of the present invention;

FIG. 2 is a schematic view of the channel opening structure of the CHA zeolite molecular sieve of the present invention;

FIG. 3 is a schematic representation of the framework structure of the MER zeolite molecular sieve of the present invention;

FIG. 4 is a schematic diagram of the pore opening structure of the MER zeolite molecular sieve of the present invention;

FIG. 5 is an XRD diffraction spectrum of the ore powder raw material roasting of the present invention;

FIG. 6 is a schematic representation of XRD zeolite structure as a crystalline phase identification of the CHA zeolite of the present invention;

FIG. 7 is a schematic diagram of XRD zeolite structure as crystal phase identification of MER zeolite according to the present invention;

FIG. 8 is an electron micrograph of the crystal morphology of the CHA and MER zeolites of the present invention;

FIG. 9 is a schematic of the synthesis of CHA and MER zeolites in accordance with an embodiment of the present invention.

Detailed Description

Preferred embodiments of the invention are described below. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the invention, and do not limit the scope of the invention.

The embodiment of the invention provides a high-ash soil-made small-pore CHA and MER zeolite, which comprises the following steps:

and step S1, roasting the mineral powder raw material. The mineral powder is prepared by selecting kaolin mineral powder with the fineness of 320 meshes, the kaolin mineral powder is roasted at high temperature to destroy the crystal structure, the crystal structure of metakaolin is amorphous, and a proper amount of CHA crystals are added into the amorphous metakaolin.

Specifically, the raw material mineral powder is roasted at 650-800 ℃ for 0.5-3 h to collapse the original crystal structure, the XRD diffraction spectrum of the raw material mineral powder is shown in figure 5, and the structural diffraction peak of the amorphous powder in the figure disappears and is shown as an amorphous diffraction area with a flat background.

Specifically, the weight ratio of the CHA seed crystal to the amorphous metakaolin mineral powder is 1-10: 50-500.

Step S2, CHA and MER Synthesis procedure. The raw material, 1mol/L or 2mol/L KOH solution and 5% CHA crystal seeds of the raw material mineral powder are uniformly mixed to form a reaction mixture, the reaction mixture is placed in a stainless steel pressure-resistant counter-pressure kettle and then placed in an oven to be heated for hydrothermal reaction, the hydrothermal reaction temperature is 130-150 ℃, and the time is 48 hours. And filtering, washing and drying the finally synthesized product to prepare the K-CHA zeolite. Similarly, the raw material, 2mol/L KOH solution and 5% CHA crystal seeds of the raw material mineral powder are uniformly mixed to form a reaction mixture, and the preparation process is the same as that of the K-CHA to obtain the K-MER zeolite.

Specifically, XRD zeolite structures of the product K-CHA zeolite and K-MER zeolite were subjected to crystallographic phase identification using a powder X-ray diffractometer, and the results are shown in FIGS. 4 and 5. Wherein A in FIG. 4 is a reference standard spectrum, B in FIG. 4 is a K-CHA zeolite prepared by the present invention, A in FIG. 5 is a reference standard spectrum, and B in FIG. 5 is a K-MER zeolite prepared by the present invention.

Specifically, the scanning range is 5-35 degrees/2 theta, and the scanning speed is 4 degrees/2 theta/min by adopting an X-ray powder diffractometer of XD2 model of Beijing Pujingyo general instruments. Meanwhile, crystal morphology and grain size of the synthesized K-CHA and K-MER zeolite molecular sieves were observed using a desk top scanning electron microscope of Phenom Prox model from Phenom, Inc. of the Netherlands, and a photograph was taken, which is shown in FIG. 6 for details. It follows that: the K-CHA zeolite is an aggregate crystal grain of a flaky or strip crystal with the size of about 3-10 microns, and the crystal appearance of the K-MER zeolite is a rectangular single crystal with the size of 2X6 microns, but the surface of the K-MER zeolite is stained with tiny grains.

Step S3, cation exchange. And (Na, K) -CHA and (Na, K) -MER cationic zeolites are obtained by performing cation exchange on the K-CHA and K-MER zeolites by taking a 0.5N NaCl solution as an ion exchange solution.

Specifically, the chemical compositions and percentages of the K-CHA zeolite, K-MER zeolite, and cationic (Na, K) -CHA zeolite, and (Na, K) -MER zeolite of the present invention were determined by S8TIGER X-ray fluorescence Scattering apparatus (XRF) of Bruker, Germany, and the SiO thereof was used as the measurement data₂、Al₂O₃The molar ratio of silica to alumina (SAR) was calculated. Wherein the results of the compositional analyses of K-CHA, K-MER and (Na, K) -CHA, (Na, K) -MER are shown in Table 2:

TABLE 2

From the above data, it is seen that the SAR of the K-CHA and K-MER zeolites prepared in KOH solution is significantly higher than the SAR of the metakaolin starting material from which they were prepared. Mainly because the SAR of naturally occurring natural mineral Na, Ca-CHA and Ba-MER zeolite single crystals is close to 4, it is apparent that the above data is an equilibrium composition of the low-silicon CHA structure zeolite and MER zeolite crystal phases.

Specifically, the temperature of the exchange was 95 ℃ for 2 hours. The K-CHA or K-MER zeolite: the NaCl solution is 1:10, the exchange times are 3 times, deionized water is used for washing 3 times after each exchange, and the filter cake after suction filtration can be subjected to next ion exchange.

Specifically, the NaCl solution was subjected to 3 cation exchanges, the K of the K-CHA zeolite₂The O content decreased from 13.5 to 5.06% of the (K, Na) -CHA zeolite, and the degree of exchange reached 62.5%. In comparison with K-MER zeolites, the K₂The O content was reduced from 14.3% to 6.88% of the (K, Na) -MER zeolite, and the degree of exchange reached 48.1%, which was lower than that of the K-CHA zeolite. The two low-silicon small-hole zeolite molecular sieves synthesized by the method have the common characteristic of good zeolite molecular sieves, namely cation exchange property. Since the MER zeolite has an average pore diameter of 0.34nm, it is less than 0.38nm for the CHA. In addition, CHA zeolite is a straight pore channel, and large-volume pore cages which are mutually connected in series are arranged in the pore channel, so that the CHA zeolite is beneficial to relatively easy ion inlet, ion outlet and ion exchange. The MER zeolite has small pore openings, and pore passages in different directions are staggered to form small cages which are not beneficial to cation inlet and outlet for ion exchange.

The adsorption measurements of K-CHA zeolite, K-MER zeolite, (Na, K) -CHA zeolite and (Na, K) -MER zeolite with a specific surface area and pore size analyzer by the static volume method of 3H-2000PS2 from Behcet instruments, Inc., are shown in Table 3:

TABLE 3

From the above data analysis, it is shown that the low temperature nitrogen adsorption performance of the metakaolin synthesized low silicon K-CHA and K-MER zeolites is not outstanding and does not have the fundamental properties of the microporous structure that the structure type zeolite should have. The reason for this is that the kinetic diameter of the adsorbate nitrogen molecule used for low temperature nitrogen adsorption is 0.3nm, and although it can enter K-CHA zeolite having an average pore diameter of 0.38nm and K-MER zeolite having an average pore diameter of 0.34nm to be adsorbed, SAR is in the poresAbout 3.3K-CHA zeolite (Si/Al atomic ratio of 1.7) and about 3.5K-MER zeolite (Si/Al atomic ratio of 1.8) belong to low-silicon high-aluminum zeolite and cation K balanced with negative charge of Al in framework⁺Is relatively high, and K⁺Ion diameter of 0.26nm, K⁺The CHA zeolite pore opening effective diameter is necessarily reduced from 0.38nm to 0.12nm, and the K-MER zeolite pore opening effective diameter is also reduced from 0.34nm to 0.08nm, so that nitrogen molecules cannot penetrate through the pore openings and are absorbed into the pore channels of the K-CHA and K-MER zeolites, and the BET surface area is only 12cm²The surface area and volume of micropores, which are about/g but more directly reflect the structural properties of the small-pore zeolite, are both 0. Ion-exchanging with NaCl solution for three times, and adding Na with diameter of 0.20nm⁺Cation replacement by ion exchange of about 50% of K⁺The low-temperature nitrogen adsorption property of the generated (Na, K) -CHA and (Na, K) -MER zeolites is obviously improved only by the former zeolites, and the BET surface area reaches 103cm²The volume of the micropore surface and the micropore volume is respectively increased to 62.0cm²And 0.025Ml/g, whereas the comparative (Na, K) -MER zeolites did not show any significant improvement. This is evident because the mean pore diameter of the MER zeolite is less than about 0.04nm for the CHA zeolite and the Na is slightly smaller in diameter⁺Substitute K⁺Insufficient to have an effective pore diameter to allow nitrogen molecules to enter the structural channels.

The methods of the CHA and MER zeolites of this example are illustrated by the following examples.

Example 1

Selecting 50g of roasted kaolin mineral powder and 2.5g of CHA zeolite crystals, putting the mixture into 450ml of KOH solution with the concentration of 1mol/L or 2mol/L, uniformly mixing to form a reaction mixture, pouring the reaction mixture into a 750ml of pressure-resistant stainless steel reaction kettle, sealing, and putting the reaction kettle into a homogeneous reaction oven at the temperature of 130 ℃ for reaction for 48 hours. And filtering, washing and drying the finally synthesized product to prepare the K-CHA zeolite. Similarly, 50g of calcined kaolin mineral powder and 2.5g of CHA zeolite crystals are put into 450ml of 2mol/L KOH solution and mixed evenly to form a reaction mixture, and the reaction mixture is poured into a 750ml of pressure-resistant stainless steel reaction kettle, sealed and placed in a homogeneous reaction oven at 140 ℃ for reaction for 36 hours. Finally synthesizedFiltering, washing and drying the product to prepare the K-MER zeolite. The XRD zeolite structure of the synthesized products of K-CHA and K-MER zeolite is subjected to crystalline phase identification by a powder X-ray diffractometer. Then the K-CHA and K-MER zeolites are subjected to cation exchange by taking 0.5N NaCl solution as ion exchange liquid to obtain (Na, K) -CHA and (Na, K) -MER cationic zeolites which can be applied to CO₂And CH₄CO and H in enriched and waste gas₂S、HCN、COS、NH₃And adsorbing, separating and removing toxic and harmful gases such as NOx.

Example 2

Selecting 50g of roasted kaolin mineral powder and 2.5g of CHA zeolite crystals, putting the mixture into 450ml of KOH solution with the concentration of 1mol/L or 2mol, uniformly mixing to form a reaction mixture, pouring the reaction mixture into a 750ml of pressure-resistant stainless steel reaction kettle, sealing, and putting the reaction kettle into a 150 ℃ homogeneous reaction oven for 24 hours. And filtering, washing and drying the finally synthesized product to prepare the K-CHA zeolite. Similarly, 50g of calcined kaolin mineral powder and 2.5g of CHA zeolite crystals are put into 450ml of 2mol/L KOH solution and mixed evenly to form a reaction mixture, and the reaction mixture is poured into a 750ml of pressure-resistant stainless steel reaction kettle, sealed and placed in a homogeneous reaction oven at 145 ℃ for reaction for 30 h. And filtering, washing and drying the finally synthesized product to prepare the K-MER zeolite. The XRD zeolite structure of the synthesized products of K-CHA and K-MER zeolite is subjected to crystalline phase identification by a powder X-ray diffractometer. And then carrying out cation exchange on the K-CHA and K-MER zeolites by taking a 0.5N NaCl solution as an ion exchange solution to obtain (Na, K) -CHA and (Na, K) -MER cationic zeolites, which can be applied to the enrichment of CO2 and CH4, the adsorption separation and removal of toxic and harmful gases such as CO, H2S, HCN, COS, NH3, NOx and the like in waste gas. The process parameters for each example are shown in table 4:

TABLE 4

Comparing the KOH concentration and the hydrothermal reaction temperature used in the first and second examples, the KOH solution concentration used in the present example was increased from 1.0mol/L to 2.0mol/L, and the K content of the entering product was significantly increased after the hydrothermal reaction temperature was increased from 130 ℃ to 150 ℃. The concentration of KOH solution in reactants and the hydrothermal reaction temperature are improved, which is beneficial to more K + entering the structure of the product.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.

Claims

1. A high-ash pore-made small-pore CHA and MER zeolite, comprising:

the method comprises the steps of roasting metakaolin mineral powder serving as a raw material at a high temperature to obtain amorphous mineral powder, adding a proper amount of seed crystals and a KOH solution into the amorphous powder, uniformly mixing to obtain a new reaction mixture, carrying out hydrothermal reaction on the new reaction mixture to obtain CHA and MER zeolites, and adding the product into a NaCl solution to carry out cation exchange to obtain cationic zeolites.

2. The high-ash small-pore CHA and MER zeolite as claimed in claim 1, wherein the metakaolin mineral powder has a fineness of 320 meshes, the calcination temperature is 650-800 ℃ and the calcination time is 0.5-3.0 h.

3. The high-ash small-pore CHA and MER zeolite of claim 1, wherein the hydrothermal reaction is carried out at 130-150 ℃ for 24-48 h.

4. The high-ash pore-made CHA and MER zeolite of claim 1, wherein the KOH solution is selected at a concentration of 1mol/L in the synthesized CHA zeolite and 2mol/L in the synthesized MER zeolite.

5. The high-ash earthen small-pore CHA and MER zeolite of claim 1 wherein the ratio of amorphous ore fines to KOH solution is 1: 9.

6. The high-ash earthen small-pore CHA and MER zeolite of claim 1 wherein the weight ratio of said seed crystal to amorphous ore fines is 1-10: 50-500.

7. The high-ash pore-made CHA and MER zeolite of claim 1, wherein the exchange temperature during cation exchange of the product with NaCl solution is 95 ℃ for 2h, and the K-CHA or K-MER zeolite: the NaCl solution is 1:10, the exchange times are 3 times, after each exchange, the NaCl solution is washed 3 times by deionized water, and the filter cake after suction filtration is subjected to next ion exchange.

8. The high-ash earthen small pore CHA and MER zeolite of claim 1 wherein the cationic zeolite is useful for CO₂And CH₄Enrichment, adsorption separation and removal of toxic and harmful gases in the waste gas.