Molecular sieve and preparation method thereof, and preparation method and application of molecular sieve drying agent

Abstract

The invention provides a molecular sieve and a preparation method thereof, and a preparation method and application of a molecular sieve drying agent, and belongs to the technical field of molecular sieves. The invention provides a molecular sieve preparation method, which comprises: mixing 3A molecular sieve raw powder, a first soluble divalent metal salt, a second soluble divalent metal salt and water, and carrying out ion exchange to obtain the molecular sieve, metal elements in the first soluble divalent metal salt and the second soluble divalent metal salt are independently one of second main group metal elements and are different; in the molecular sieve, the molar ratio of the total amount of substance of metal elements in the first soluble divalent metal salt and metal elements in the second soluble divalent metal salt to Al2O3 is (0.16-0.29): 1, and the molar ratio of K2O / Al2O3 is (0.20-0.40): 1.

Description

Technical Field

[0001] The invention relates to the technical field of molecular sieves, and in particular to a molecular sieve and a preparation method thereof, a preparation method of a molecular sieve desiccant and an application thereof. Background Art

[0002] The main function of molecular sieve desiccant is drying and dehydration. At the same time, due to its certain adsorption effect on air, it is used in the drying of hollow glass, polyurethane, medicinal material packaging and olefins:

[0003] High water absorption performance can prevent water vapor condensation and frost on the inner surface of insulating glass; extremely low gas adsorption performance can improve the sealing of insulating glass (molecular sieve has the ability to adsorb and analyze the dry air sealed in the middle of insulating glass, which will cause the air pressure inside the insulating glass to change and thus affect the sealing of the insulating glass);

[0004] High water absorption can prevent the polymerized polyisocyanate from reacting with trace amounts of water to form bubbles and pinholes on the surface of the cured product.

[0005] The extremely low gas adsorption performance can prevent the medicinal material packaging collar from drying out and bulging due to the absorption and decomposition of gas by itself;

[0006] The extremely low gas adsorption performance will not cause carbon deposition and deactivation of the molecular sieve due to the adsorption of olefins when drying olefins.

[0007] In the prior art, 3A, 4A, and 5A molecular sieves are commonly used as desiccants, but the water absorption performance of the above desiccants still needs to be improved, and the adsorption performance to air still needs to be further reduced. Summary of the invention

[0008] The invention provides a molecular sieve and a preparation method thereof, a preparation method of a molecular sieve desiccant and an application thereof. The molecular sieve desiccant prepared using the molecular sieve prepared by the invention as a raw material has good water absorption and low air adsorption performance.

[0009] The present invention provides a method for preparing molecular sieve raw powder, comprising the following steps:

[0010] Mixing 3A molecular sieve raw powder, a first soluble divalent metal salt, a second soluble divalent metal salt and water to perform ion exchange to obtain the molecular sieve raw powder;

[0011] The metal elements in the first soluble divalent metal salt and the second soluble divalent metal salt are independently one of the metal elements of the second main group and are different;

[0012] In the molecular sieve raw powder, the molar ratio of the total amount of metal elements in the first soluble divalent metal salt and the metal elements in the second soluble divalent metal salt to Al2O3 is 0.16-0.29:1, and the molar ratio of K2O / Al2O3 is 0.20-0.40:1.

[0013] Preferably, the ion exchange degree of the 3A molecular sieve is 48-53%.

[0014] Preferably, on a dry basis, the mass ratio of the total mass of the 3A molecular sieve, the first soluble divalent metal salt and the second soluble divalent metal salt to water is 1:4-6.

[0015] Preferably, the metal element in the first soluble divalent metal salt and the second soluble divalent metal salt is independently one of beryllium, magnesium, calcium, strontium and barium.

[0016] Preferably, the first soluble divalent metal salt and the second soluble divalent metal salt independently include one or more of hydrochloride, nitrate and acetate.

[0017] Preferably, the first soluble divalent metal salt includes one or more of calcium chloride, calcium nitrate and calcium acetate; the second soluble divalent metal salt includes one or more of barium chloride, magnesium chloride, strontium chloride, beryllium chloride, barium nitrate, magnesium nitrate, strontium nitrate, beryllium nitrate, barium acetate, magnesium acetate, strontium acetate and beryllium acetate.

[0018] Preferably, on a dry basis, the mass ratio of the 3A molecular sieve raw powder to the first soluble divalent metal salt on a calcium chloride basis is 36:2.2-3.6;

[0019] On a dry basis, the mass ratio of the 3A molecular sieve raw powder to the second soluble divalent metal salt in the form of barium chloride, magnesium chloride, strontium chloride or beryllium chloride is 36:0.37-1.2.

[0020] The present invention also provides a molecular sieve raw powder prepared by the preparation method described in the above technical scheme, in which the molar ratio of CaO to Al2O3 is 0.15-0.25:1, the molar ratio of K2O to Al2O3 is 0.20-0.40:1, and the molar ratio of BaO or MgO or BeO or SrO to Al2O3 is 0.015-0.03:1.

[0021] The present invention also provides a method for preparing a molecular sieve desiccant, comprising the following steps:

[0022] The molecular sieve desiccant is obtained by calcining the formed product of the molecular sieve raw powder and the adhesive described in the above technical solution or the molecular sieve raw powder described in the above technical solution.

[0023] The present invention also provides the use of the molecular sieve desiccant prepared by the preparation method described in the above technical solution in hollow glass, polyurethane, medicinal material packaging or olefin drying.

[0024] The present invention provides a method for preparing a molecular sieve, comprising the following steps:

[0025] Mixing 3A molecular sieve, a first soluble divalent metal salt, a second soluble divalent metal salt and water to perform ion exchange to obtain the molecular sieve;

[0026] The metal elements in the first soluble divalent metal salt and the second soluble divalent metal salt are independently one of the metal elements of the second main group and are different;

[0027] In the molecular sieve, the molar ratio of the total amount of metal elements in the first soluble divalent metal salt and the metal elements in the second soluble divalent metal salt to Al2O3 is 0.16-0.29:1, and the molar ratio of K2O / Al2O3 is 0.20-0.40:1.

[0028] During ion exchange, one divalent metal ion can simultaneously exchange two Na + , K + After exchanging the above divalent cations to a certain extent (the molar ratio of the total amount of metal elements in the first soluble divalent metal salt and the total amount of metal elements in the second soluble divalent metal salt to Al2O3 is 0.16-0.29:1, and the molar ratio of K2O / Al2O3 is 0.20-0.40:1), the pore size will be corrected to control its opening diameter to be slightly larger than that of water molecules and smaller than that of other molecules (such as nitrogen, oxygen, carbon dioxide, etc.), thereby improving the water absorption of the molecular sieve desiccant prepared with it as raw material and reducing the adsorption performance of the molecular sieve desiccant prepared with it as raw material to air.

[0029] The potassium cost of the commonly used 3A desiccant is high. The present invention reduces the potassium content in the molecular sieve and replaces it with calcium which has a lower price, thereby reducing the cost of the molecular sieve.

[0030] When the first soluble divalent metal salt is a calcium salt, the second soluble divalent metal salt is a barium salt, a magnesium salt, a strontium salt or a beryllium salt, and in the prepared molecular sieve: the molar ratio of CaO to Al2O3 is 0.15-0.25:1, the molar ratio of K2O / Al2O3 is 0.20-0.40:1, and the molar ratio of BaO or MgO or BeO or SrO to Al2O3 is 0.015-0.03:1, the water absorption of the molecular sieve desiccant prepared using the same as the raw material can be further improved and the adsorption performance to air can be reduced. DETAILED DESCRIPTION

[0031] The present invention provides a method for preparing a molecular sieve, comprising the following steps:

[0032] Mixing 3A molecular sieve, a first soluble divalent metal salt, a second soluble divalent metal salt and water to perform ion exchange to obtain the molecular sieve;

[0033] The metal elements in the first soluble divalent metal salt and the second soluble divalent metal salt are independently one of the metal elements of the second main group and are different;

[0034] In the molecular sieve, the molar ratio of the total amount of metal elements in the first soluble divalent metal salt and the metal elements in the second soluble divalent metal salt to Al2O3 is 0.16-0.29:1, and the molar ratio of K2O / Al2O3 is 0.20-0.40:1.

[0035] In the present invention, the method for preparing the 3A molecular sieve raw powder preferably comprises the following steps:

[0036] The soluble potassium salt, 4A molecular sieve raw powder and water are mixed to carry out ion exchange to obtain 3A molecular sieve raw powder.

[0037] The present invention has no particular limitation on the preparation method of the 4A molecular sieve raw powder, and any method familiar to those skilled in the art may be used.

[0038] In the present invention, the soluble potassium salt includes one or more of potassium chloride, potassium nitrate, potassium acetate and potassium sulfate.

[0039] In the present invention, the D50 of the 4A molecular sieve raw powder is preferably 0.5-6 μm, more preferably 0.5-5 μm; the pH value is preferably ≤11, more preferably 7-9.

[0040] In the present invention, the ion exchange degree of the 3A molecular sieve raw powder is preferably 33-53%, more preferably 50%.

[0041] In the present invention, the mass ratio of the soluble potassium salt to the 4A molecular sieve calculated as potassium oxide is preferably 1:8-15; the mass ratio of the 4A molecular sieve raw powder to water is preferably 1:3-9, more preferably 1:4-6.

[0042] In the present invention, the ion exchange temperature is preferably 50-90°C, more preferably 60°C.

[0043] After the ion exchange is completed, the present invention preferably further comprises: filtering, washing and drying the obtained ion exchange product to obtain 3A molecular sieve raw powder.

[0044] In the present invention, the water content of the 3A molecular sieve raw powder is preferably 15 to 35 wt %, more preferably 25 to 32 wt %.

[0045] The present invention has no particular limitation on the washing, and the unreacted potassium salt can be washed away using a scheme well known to those skilled in the art.

[0046] In the present invention, on a dry basis, the mass ratio of the total mass of the 3A molecular sieve raw powder, the first soluble divalent metal salt and the second soluble divalent metal salt to water is preferably 1:4-6, more preferably 1:4.5-5; on a dry basis, the mass ratio of the 3A molecular sieve raw powder to the first soluble divalent metal salt calculated as calcium chloride is preferably 36:2.2-3.6, more preferably 36:2.5-3.2, and further preferably 36:2.6-3; on a dry basis, the mass ratio of the 3A molecular sieve raw powder to the second soluble divalent metal salt calculated as barium chloride, magnesium chloride, strontium chloride or beryllium chloride is 36:0.37-1.2, more preferably 36:0.5-0.8. In the present invention, the calculation method in terms of calcium chloride, barium chloride, magnesium chloride, strontium chloride or beryllium chloride is to calculate the mass of calcium chloride, barium chloride, magnesium chloride, strontium chloride or beryllium chloride according to the amount of the substance of the metal element in the salt. The metal element in the first soluble divalent metal salt and the second soluble divalent metal salt is independently one of the second main group metal elements, and the metal element in the first soluble divalent metal salt is different from the metal element in the second soluble divalent metal salt; the metal element in the first soluble divalent metal salt and the second soluble divalent metal salt is preferably independently one of beryllium, magnesium, calcium, strontium and barium.

[0047] In the present invention, the first soluble divalent metal salt and the second soluble divalent metal salt independently include one or more of hydrochloride, nitrate and acetate; the first soluble divalent metal salt includes one or more of calcium chloride, calcium nitrate and calcium acetate; the second soluble divalent metal salt includes one or more of barium chloride, magnesium chloride, strontium chloride, beryllium chloride, barium nitrate, magnesium nitrate, strontium nitrate, beryllium nitrate, barium acetate, magnesium acetate, strontium acetate and beryllium acetate.

[0048] In the present invention, the ion exchange temperature is preferably 50 to 90° C., more preferably 60° C.; the time is preferably 1 to 12 hours, more preferably 5 to 8 hours.

[0049] After the ion exchange is completed, the present invention preferably further comprises: filtering, washing and drying the obtained ion exchange product to obtain the molecular sieve.

[0050] In the present invention, in the molecular sieve: the molar ratio of the total amount of metal elements in the first soluble divalent metal salt and the metal elements in the second soluble divalent metal salt to Al2O3 is 0.16-0.29:1, and the molar ratio of K2O / Al2O3 is 0.20-0.40:1.

[0051] The present invention also provides a molecular sieve raw powder prepared by the preparation method described in the above technical scheme, in which the molar ratio of CaO to Al2O3 is 0.15-0.25:1, the molar ratio of K2O to Al2O3 is 0.20-0.40:1, and the molar ratio of BaO or MgO or BeO or SrO to Al2O3 is 0.015-0.03:1.

[0052] In the present invention, the pH of the molecular sieve raw powder is preferably 7 to 11, and more preferably 9.5 to 10.8.

[0053] The present invention also provides a method for preparing a molecular sieve desiccant, comprising the following steps:

[0054] The molecular sieve is obtained by calcining the molded product of the molecular sieve raw powder and the adhesive described in the above technical solution and the molecular sieve raw powder described in the above technical solution.

[0055] In the present invention, the mass ratio of the molecular sieve raw powder to the adhesive is preferably 70:30 to 95:5; the adhesive is preferably one or more of kaolin, attapulgite and bentonite.

[0056] In the present invention, the calcination temperature is preferably 450-650° C., and the calcination time is preferably 0.5-5.5 h. The calcination further removes moisture.

[0057] In the present invention, the moisture content of the molecular sieve desiccant is preferably ≤5wt%, and more preferably 1.5-3wt%.

[0058] The present invention also provides the use of the molecular sieve desiccant described in the above technical solution in hollow glass, polyurethane, medicinal material packaging or olefin drying.

[0059] The molecular sieve and its preparation method, the preparation method of the molecular sieve desiccant and its application provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be understood as limiting the scope of protection of the present invention.

[0060] Example 1

[0061] (1) 0.185 mol Al2O3, 0.364 mol SiO2, 0.552 mol Na2O, add water to 526 mL, gel for 1 hour, age at 75°C for 2 hours, crystallize at 95°C for 7 hours, separate the solid and liquid, and dry the obtained solid to obtain 4A molecular sieve raw powder with different water contents. Al2O3 is provided by sodium aluminate solution, SiO2 is provided by sodium carbonate solution, and the remaining Na2O is provided by liquid caustic soda solution.

[0062] Potassium chloride, water and 4A molecular sieve raw powder (on a dry basis, the mass ratio of potassium chloride to 4A molecular sieve is 1.1:1, and the mass ratio of 4A molecular sieve to water on a dry basis is 1:6) are mixed and ion exchange is performed at 70-90°C for 3 hours, and then the obtained ion exchange product is filtered, washed and dried to obtain 3A molecular sieve raw powder with different water contents.

[0063] (2) Weigh 13.60 g of CaCl2·2H2O, with a CaCl2 content of ≥72%, 147 g of 3A molecular sieve powder, with a potassium exchange degree of 48% and a water content of 32 wt%; and 2.8 g of BaCl2;

[0064] On a dry basis, the mass ratio of 3A molecular sieve raw powder: CaCl2: BaCl2 is 100: 9.8: 2.8;

[0065] (3) Dissolve CaCl2·2H2O and BaCl2 in 600 mL of deionized water, add 3A molecular sieve powder, and stir in a constant temperature water bath at 80°C for 3 h;

[0066] The material in step (3) is washed, filtered, dried (100° C., 20 min) and calcined (calcination temperature is 550° C., time is 2 h) to obtain a novel high water adsorption selective molecular sieve desiccant.

[0067] Example 2

[0068] The only difference from Comparative Example 1 is:

[0069] Weigh 11.67g CaCl2·2H2O, CaCl2 content ≥72%, 2.8g BaCl2;

[0070] On a dry basis, the mass ratio of 3A molecular sieve raw powder: CaCl2: BaCl2 is 100: 8.4: 2.8.

[0071] Example 3

[0072] (1) Weigh 126 g of 3A molecular sieve raw powder (the only difference from Example 1 is that the water content is 20.6 wt%);

[0073] (2) Weigh 8.66 g of CaCl2·2H2O, with a CaCl2 content of ≥72%, and 2.8 g of BaCl2;

[0074] On a dry basis, the mass ratio of 3A molecular sieve raw powder: CaCl2: BaCl2 is 100: 6.2: 2.8;

[0075] (3) Dissolve CaCl2·2H2O and BaCl2 in 600 mL of deionized water, add 3A molecular sieve powder, and stir in a constant temperature water bath at 80°C for 3 h;

[0076] The material in step (3) is washed, filtered, dried (100° C., 20 min) and calcined (calcination temperature is 550° C., time is 2 h) to obtain a novel high water adsorption selective molecular sieve desiccant.

[0077] Example 4

[0078] (1) The 4A molecular sieve raw powder (water content 20 wt%) prepared in Example 1 was added to a 400 mL deionized water beaker for slurry to obtain a slurry, and then 42 g of potassium sulfate was added to dissolve it, and the mixture was exchanged in a water bath at 80° C. for 3 h to obtain a 3A molecular sieve raw powder;

[0079] (2) Weigh 11.67 g of CaCl2·2H2O, with a CaCl2 content of ≥72%, 147 g of 3A molecular sieve powder, with a potassium exchange degree of 50% and a water content of 32 wt%; and 1.4 g of BaCl2;

[0080] On a dry basis, the mass ratio of 3A molecular sieve raw powder: CaCl2 is 100:8.4:1.4;

[0081] (3) Dissolve CaCl2·2H2O in 600 mL of deionized water, add 3A molecular sieve powder, and stir in a constant temperature water bath at 80°C for 3 h;

[0082] The material in step (3) is washed, filtered, dried (100° C., 20 min) and calcined (calcination temperature is 550° C., time is 2 h) to obtain a novel high water adsorption selective molecular sieve desiccant.

[0083] Example 5

[0084] (1) Weigh 147 g of the 3A molecular sieve powder prepared in Example 4, wherein the potassium exchange degree is 50% and the water content is 32 wt %;

[0085] (2) Weigh 11.67 g of CaCl2·2H2O, with a CaCl2 content of ≥72%; 2.8 g of BaCl2;

[0086] On a dry basis, the mass ratio of 3A molecular sieve raw powder: CaCl2: BaCl2 is 100: 8.4: 2.8;

[0087] (3) Dissolve CaCl2·2H2O in 600 mL of deionized water, add 3A molecular sieve powder, and stir in a constant temperature water bath at 80°C for 3 h;

[0088] The material in step (3) is washed, filtered, dried (100° C., 20 min) and calcined (calcination temperature is 550° C., time is 2 h) to obtain a novel high water adsorption selective molecular sieve desiccant.

[0089] Comparative Example 1

[0090] (1) Weigh 166.7 g of the 4A molecular sieve powder prepared in Example 1, with a water content of 40 wt %;

[0091] (2) Weigh 14.60 g of CaCl2·2H2O, with a CaCl2 content of ≥72%; 45.4 g of KCl, with a KCl content of ≥98%;

[0092] On a dry basis, the mass ratio of 4A molecular sieve raw powder: CaCl2: KCl is 100: 10.5: 44.4;

[0093] (3) After dissolving CaCl2·2H2O and KCl in 600 mL of deionized water, add 4A molecular sieve powder and stir in a constant temperature water bath at 80°C for 3 h;

[0094] The material in step (3) is washed, filtered, dried (100° C., 20 min) and calcined (calcination temperature is 550° C., time is 2 h) to obtain a novel high water adsorption selective molecular sieve desiccant.

[0095] Comparative Example 2

[0096] The only difference from Comparative Example 1 is:

[0097] Weigh 11.9 g of CaCl2·2H2O, with a CaCl2 content of ≥72%; 45.4 g of KCl, with a KCl content of ≥98%;

[0098] On a dry basis, the mass ratio of 4A molecular sieve raw powder: CaCl2: KCl in Example 1 is 100: 8.6: 44.4.

[0099] Comparative Example 3

[0100] The only difference from Example 1 is: 14.9 g of CaCl2·2H2O, CaCl2 content ≥ 72%; 2.8 g of BaCl2;

[0101] On a dry basis, the mass ratio of 3A molecular sieve raw powder: CaCl2: BaCl2 is 100: 10.73: 2.8.

[0102] Comparative Example 4

[0103] The only difference from Example 1 is: 8.0 g of CaCl2·2H2O, CaCl2 content ≥ 72%; 2.8 g of BaCl2;

[0104] On a dry basis, the mass ratio of 3A molecular sieve raw powder: CaCl2: BaCl2 is 100: 5.76: 2.8.

[0105] Table 1 Main index measurement results of molecular sieve desiccants prepared in Examples 1 to 5 and Comparative Examples 1 to 4

[0106]

[0107]

[0108] Table 2 pH of the molecular sieve after drying in step (3) of Examples 1 to 5 and Comparative Examples 1 to 4

[0109]

[0110] Note: The pH test method is: disperse 4 g of dried molecular sieve in 80 mL of water and measure the pH value of the dispersion.

[0111] 40g of the 4A molecular sieve raw powder prepared in Example 1 (water content is 20wt%) is added to a 400mL deionized water beaker and slurried to obtain a slurry; after preparing 3 portions of the above slurry, 36g, 41g and 50g of potassium sulfate are added respectively to dissolve, exchanged in an 80°C water bath for 3h, washed, filtered and dried (100°C, 20min) to obtain 3A sample 1~3 precursors; 3A sample 1~3 precursors are calcined (calcination temperature is 550°C, time is 2h) to obtain 3A samples 1~3 respectively.

[0112] Table 33A Main index test results of samples 1 to 3

[0113] Exchange Degree Static water adsorption <![CDATA[BETCO2 adsorption]]> <![CDATA[Static water adsorption / BET CO2]]> 3A sample 1 43％ 25.94％ 11.93％ 2.17 3A Sample 2 48％ 25.42％ 9.96％ 2.55 3A sample 3 62％ 24.51％ 10.93％ 2.24

[0114] Table 43 pH of sample 1 to 3 precursors

[0115] 3A-like 1 precursor 3A-like 2 precursor 3A-like 3 precursor PH 10.63 10.60 10.65

[0116] It can be seen from Tables 1 to 4 that the 4A molecular sieve raw powder is first subjected to potassium ion exchange to obtain the 3A molecular sieve raw powder, and then subjected to calcium ion exchange to finally obtain the molecular sieve raw powder. The molar ratio of CaO to Al2O3 is 0.15-0.25:1, the molar ratio of K2O / Al2O3 is 0.20-0.40:1, and the molar ratio of BaO / Al2O3 is 0.015-0.03:1, which can further improve the water absorption of the molecular sieve desiccant and reduce the adsorption performance to air.

[0117] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for preparing molecular sieve raw powder, characterized in that: The following steps are involved: Mixing 3A molecular sieve raw powder, a first soluble divalent metal salt, a second soluble divalent metal salt and water to perform ion exchange to obtain the molecular sieve raw powder; The metal elements in the first soluble divalent metal salt and the second soluble divalent metal salt are independently one of the metal elements of the second main group and are different; In the molecular sieve raw powder, the molar ratio of the total amount of metal elements in the first soluble divalent metal salt and the metal elements in the second soluble divalent metal salt to Al2O3 is 0.16-0.29:1, and the molar ratio of K2O / Al2O3 is 0.20-0.40:

1.

2. The preparation method according to claim 1, characterized in that: The ion exchange degree of the 3A molecular sieve is 48-53%.

3. The preparation method according to claim 1, characterized in that: On a dry basis, the mass ratio of the total mass of the 3A molecular sieve, the first soluble divalent metal salt and the second soluble divalent metal salt to water is 1:4-6.

4. The preparation method according to claim 1, characterized in that: The metal element in the first soluble divalent metal salt and the second soluble divalent metal salt is independently one of beryllium, magnesium, calcium, strontium and barium.

5. The preparation method according to claim 1 or 4, characterized in that: The first soluble divalent metal salt and the second soluble divalent metal salt independently include one or more of hydrochloride, nitrate and acetate.

6. The preparation method according to claim 5, characterized in that: The first soluble divalent metal salt includes one or more of calcium chloride, calcium nitrate and calcium acetate; the second soluble divalent metal salt includes one or more of barium chloride, magnesium chloride, strontium chloride, beryllium chloride, barium nitrate, magnesium nitrate, strontium nitrate, beryllium nitrate, barium acetate, magnesium acetate, strontium acetate and beryllium acetate.

7. The preparation method according to claim 6, characterized in that: On a dry basis, the mass ratio of the 3A molecular sieve raw powder to the first soluble divalent metal salt on a calcium chloride basis is 36:2.2-3.6; On a dry basis, the mass ratio of the 3A molecular sieve raw powder to the second soluble divalent metal salt in the form of barium chloride, magnesium chloride, strontium chloride or beryllium chloride is 36:0.37-1.

2.

8. The molecular sieve raw powder prepared by the preparation method according to any one of claims 1 to 7, characterized in that: In the molecular sieve raw powder, the molar ratio of CaO to Al2O3 is 0.15-0.25:1, the molar ratio of K2O to Al2O3 is 0.20-0.40:1, and the molar ratio of BaO or MgO or BeO or SrO to Al2O3 is 0.015-0.03:

1.

9. A method for preparing a molecular sieve desiccant, characterized in that: The following steps are involved: The molecular sieve desiccant is obtained by calcining the molded product of the molecular sieve raw powder and the adhesive as claimed in claim 8 or the molecular sieve raw powder as claimed in claim 8.

10. Use of the molecular sieve desiccant prepared by the preparation method according to claim 9 in hollow glass, polyurethane, medicinal material packaging or olefin drying.

Images