Enhanced molecular sieve and preparation method thereof
Technical Field
The invention relates to the field of molecular sieves, in particular to an enhanced molecular sieve and a preparation method thereof.
Background
The molecular sieve is a material containing precise and single tiny holes, the crystal holes of the molecular sieve have strong polarity and coulomb field, and the molecular sieve has strong adsorption capacity to polar molecules (such as water) and unsaturated molecules; the molecular sieve has pores with uniform diameter, and the pores can adsorb molecules with smaller diameter to the inside of the pore and have preferential adsorption capacity to polar molecules and unsaturated molecules, so that the molecular sieve can separate molecules with different polarity degrees, saturation degrees, molecular sizes and boiling points, namely has the function of sieving the molecules.
The current Chinese patent with application number CN201310131306.6 discloses a low-potassium type 3A molecular sieve and a preparation method thereof, wherein the low-potassium type 3A molecular sieve is prepared by taking 4A molecular sieve raw powder, potassium-containing electrolyte and clay as raw materials, adopting a solid-state ion exchange process, adding water, mixing, forming and roasting.
The invention also aims to provide the molecular sieve and the preparation method thereof, and the prepared molecular sieve has good use performance.
Disclosure of Invention
Aiming at the defects in the prior art, the invention aims to provide the enhanced molecular sieve and the preparation method thereof.
In order to achieve the purpose, the invention provides the following technical scheme:
the reinforced molecular sieve comprises the following raw materials in parts by weight: 50-80 parts of molecular sieve raw powder, 20-40 parts of clay and 16-27 parts of reinforced adhesive;
the reinforced adhesive comprises the following components in parts by weight: 5-10 parts of acidolysis starch, 8-17 parts of etherified starch, 11-20 parts of nano aluminum oxide, 14-21 parts of nano silicon dioxide and 4-8 parts of anti-cracking agent.
By adopting the technical scheme, when the molecular sieve is prepared, the raw powder of the molecular sieve with the corresponding model is directly selected, and is combined with the reinforced adhesive under a specific proportion to obtain the molecular sieve with the required model through a series of steps;
in addition, in the reinforcing adhesive, the nano silicon dioxide and the nano aluminum oxide are used as reinforcing main bodies, so that the strength of the molecular sieve is effectively improved; forming a bonding system by using acidolysis starch and etherified starch, so that the enhanced adhesive is fully bonded with the molecular sieve system; the acidolysis starch has multiple linear chain structures, small molecular weight and relatively low viscosity, and can avoid caking due to overlarge viscosity of a mixing system in the preparation process of the molecular sieve and relatively improve the smoothness of the mixing system; the etherified starch has larger molecular weight and high viscosity stability, can meet the bonding requirement of a molecular sieve system, is used as a main body mainly playing a role in tackifying, has good acid and alkali resistance, moldability and smoothness, and can well improve the surface quality and the bonding strength of the molecular sieve; meanwhile, the cracking resistance agent is added, so that the problem that the molecular sieve cracks due to dehydration after water absorption expansion of acid hydrolysis starch and etherified starch is effectively solved; therefore, the invention can directly prepare the corresponding molecular sieve by adopting the corresponding molecular sieve raw powder, and the prepared molecular sieve has good use performance such as strength and the like.
The invention is further provided that the raw materials comprise the following components in parts by weight: 65-77 parts of molecular sieve raw powder, 26-45 parts of clay and 19-23 parts of reinforced adhesive;
the reinforced adhesive comprises the following components in parts by weight: 6-8 parts of acidolysis starch, 12-16 parts of etherified starch, 16-19 parts of nano alumina, 17-20 parts of nano silicon dioxide and 5-7 parts of anti-cracking agent.
By adopting the technical scheme, the content range of each component in the molecular sieve mixing system is further limited, so that each component in the molecular sieve mixing system achieves a better proportion, and the service performance and the strength of the molecular sieve are further improved.
The invention is further provided that the raw materials comprise the following components in parts by weight: 70 parts of molecular sieve raw powder, 30 parts of clay and 21 parts of reinforcing adhesive;
the reinforced adhesive comprises the following components in parts by weight: 7 parts of acidolysis starch, 14 parts of etherified starch, 17 parts of nano-alumina, 18 parts of nano-silica and 6 parts of anti-cracking agent.
By adopting the technical scheme, the content of each component in the molecular sieve mixing system is further determined, so that each component in the molecular sieve mixing system reaches the optimal proportion, and the service performance and the strength of the molecular sieve are greatly improved.
The invention is further provided that the clay is one or more of attapulgite and bentonite, and the ratio of the particle size of the clay to the particle size of the molecular sieve raw powder is (1-2): (9-13).
By adopting the technical scheme, the attapulgite is used as a clay mineral containing water and rich in magnesium aluminosilicate, the bentonite is used as a nonmetal mineral product taking the montmorillonite as a main mineral component, and the attapulgite and the bentonite both have good water absorption performance, so that a good bonding effect is achieved in the preparation process of the molecular sieve; the ratio of the particle size of the clay to the specific particle size of the molecular sieve raw powder ensures that the clay with small particle size can be fully adhered to the surface of the molecular sieve raw powder with large particle size, fully bonds the molecular sieve raw powder and reduces the blockage of the pores of the molecular sieve raw powder.
The invention is further provided that the anti-cracking agent comprises the following components in parts by weight: 20-36 parts of glass fiber powder and 14-20 parts of lignin fiber powder.
By adopting the technical scheme, the glass fiber powder is used as a thermosetting material, has excellent strength, and is mainly used for improving the cracking resistance of the molecular sieve under the mechanical action; the lignin fiber powder is used as fiber powder, has good toughness so as to improve the cracking resistance of the molecular sieve, and can be embedded into molecular gaps of the acidolysis starch and the etherified starch, so that the molecular gaps of the acidolysis starch and the etherified starch are properly filled, the structural shrinkage of the acidolysis starch and the etherified starch, particularly the acidolysis starch in the water absorption and water loss processes is reduced, and the cracking of the molecular sieve is reduced.
The invention is further configured such that the etherified starch is hydroxypropyl starch.
By adopting the technical scheme, the hydroxypropyl in the hydroxypropyl starch can generate a steric hindrance effect to prevent the starch chains from being aggregated and crystallized, and meanwhile, the hydroxypropyl starch has strong fluidity, weak coagulability and high stability, and plays a good bonding role in a molecular sieve mixing system, so that the molecular sieve mixing system has better smoothness in the forming process, and the surface quality of the molecular sieve is improved.
The invention further provides that the preparation method of the reinforced adhesive comprises the following components:
(1) mixing the acidolysis starch and the anti-cracking agent in a mixer at the rotating speed of 500-;
(2) and (2) adding nano aluminum oxide and nano silicon dioxide into the mixture obtained in the step (1), mixing for 10 +/-2 min, adding etherified starch, and continuously mixing for 20 +/-3 min to obtain the reinforced adhesive.
By adopting the technical scheme, because the water absorption of the acid hydrolysis starch is stronger, the acid hydrolysis starch and the anti-cracking agent are independently and pre-mixed, so that the acid hydrolysis starch and the anti-cracking agent fully act, and the anti-cracking performance of the molecular sieve can be further effectively improved; and meanwhile, etherified starch is added finally, so that the acidolysis starch and the etherified starch can fully wrap the nano-alumina and the nano-silica, thereby improving the mixing and bonding of the nano-alumina and the nano-silica to a molecular sieve mixing material system.
Another object of the present invention is to provide a method for preparing an enhanced molecular sieve, which comprises the following steps:
(1) putting the molecular sieve raw powder, the clay and the reinforced adhesive into a mixer, stirring for 40 +/-5 min at the rotating speed of 800 plus one year and 900 revolutions per minute, and fully mixing to obtain premixed powder;
(2) putting the premixed powder into a ball forming mill, rotating the ball forming mill at the rotating speed of 20 +/-2 revolutions per minute, and spraying water mist into the premixed powder at the speed of 0.5 +/-0.1 m2/S to obtain a prefabricated ball particle with a specified diameter;
(3) putting the prefabricated pellets into a low-temperature dehumidifier, and removing 20 +/-1% of water in parts by mass at the temperature of 200 +/-20 ℃;
(4) and (4) putting the prefabricated pellets in the step (3) into a high-temperature activating machine, and activating at 500 +/-20 ℃ to obtain the molecular sieve with the water content of 5-6% in parts by mass.
By adopting the technical scheme, the prepared molecular sieve has uniform particle size and excellent service performance under the control of the parameter conditions, and simultaneously has good strength and prolonged service life.
In conclusion, the invention has the following beneficial effects:
1. when the molecular sieve is prepared, the molecular sieve raw powder with the corresponding model is directly selected, and combined with the reinforcing adhesive in a specific ratio to obtain the molecular sieve with the required model through a series of steps;
2. in the reinforced adhesive, nano silicon dioxide and nano aluminum oxide are used as a reinforced main body, so that the strength of the molecular sieve is improved; forming a bonding system by using acidolysis starch and etherified starch, so that the enhanced adhesive is fully bonded with the molecular sieve system; the acidolysis starch has multiple linear chain structures, small molecular weight and relatively low viscosity, and can avoid caking due to overlarge viscosity of a mixing system in the preparation process of the molecular sieve and relatively improve the smoothness of the mixing system; the etherified starch has larger molecular weight and high viscosity stability, can meet the bonding requirement of a molecular sieve system, is used as a main body mainly playing a role in tackifying, has good acid and alkali resistance, moldability and smoothness, and can well improve the surface quality and the bonding strength of the molecular sieve; meanwhile, the cracking resistance agent is added, so that the problem that the molecular sieve cracks due to dehydration after water absorption expansion of acid hydrolysis starch and etherified starch is effectively solved; 3. under the control of the parameter conditions, the prepared molecular sieve has the advantages of uniform particle size, excellent service performance, good strength and prolonged service life.
Detailed Description
The present invention will be described in further detail with reference to examples.
The first embodiment is as follows:
the reinforced molecular sieve comprises the following raw materials in parts by weight: 50 parts of molecular sieve raw powder, 20 parts of clay and 16 parts of reinforcing adhesive;
the reinforced adhesive comprises the following components in parts by weight: 5 parts of acidolysis starch, 8 parts of etherified starch, 11 parts of nano-alumina, 14 parts of nano-silica and 4 parts of anti-cracking agent.
Wherein:
the clay is attapulgite, and the ratio of the particle size of the attapulgite to the particle size of the molecular sieve raw powder is 1: 13.
the anti-cracking agent comprises the following components in parts by weight: 20 parts of glass fiber powder and 14 parts of lignin fiber powder.
The etherified starch is hydroxypropyl starch.
Example two:
the reinforced molecular sieve comprises the following raw materials in parts by weight: 65 parts of molecular sieve raw powder, 26 parts of clay and 19 parts of reinforcing adhesive;
the reinforced adhesive comprises the following components in parts by weight: 6 parts of acidolysis starch, 12 parts of etherified starch, 16 parts of nano-alumina, 17 parts of nano-silica and 5 parts of anti-cracking agent.
Wherein:
the clay is bentonite, and the ratio of the particle size of the bentonite to the particle size of the molecular sieve raw powder is 1: 9.
the anti-cracking agent comprises the following components in parts by weight: 22 parts of glass fiber powder and 16 parts of lignin fiber powder.
The etherified starch is hydroxypropyl starch.
Example three:
the reinforced molecular sieve comprises the following raw materials in parts by weight: 70 parts of molecular sieve raw powder, 30 parts of clay and 21 parts of reinforcing adhesive;
the reinforced adhesive comprises the following components in parts by weight: 7 parts of acidolysis starch, 14 parts of etherified starch, 17 parts of nano-alumina, 18 parts of nano-silica and 6 parts of anti-cracking agent.
Wherein:
the clay is attapulgite, and the ratio of the particle size of the attapulgite to the particle size of the molecular sieve raw powder is 2: 11.
the anti-cracking agent comprises the following components in parts by weight: 26 parts of glass fiber powder and 16 parts of lignin fiber powder.
The etherified starch is hydroxypropyl starch.
Example four:
the reinforced molecular sieve comprises the following raw materials in parts by weight: 77 parts of molecular sieve raw powder, 45 parts of clay and 23 parts of reinforcing adhesive;
the reinforced adhesive comprises the following components in parts by weight: 8 parts of acidolysis starch, 16 parts of etherified starch, 19 parts of nano-alumina, 20 parts of nano-silica and 7 parts of anti-cracking agent.
Wherein:
the clay is attapulgite, and the ratio of the particle size of the attapulgite to the particle size of the molecular sieve raw powder is 2: 13.
the anti-cracking agent comprises the following components in parts by weight: 36 parts of glass fiber powder and 20 parts of lignin fiber powder.
The etherified starch is hydroxypropyl starch.
Example five:
the reinforced molecular sieve comprises the following raw materials in parts by weight: 80 parts of molecular sieve raw powder, 40 parts of clay and 27 parts of reinforcing adhesive;
the reinforced adhesive comprises the following components in parts by weight: 10 parts of acidolysis starch, 17 parts of etherified starch, 20 parts of nano-alumina, 21 parts of nano-silica and 8 parts of anti-cracking agent.
Wherein:
the clay is bentonite, and the ratio of the particle size of the bentonite to the particle size of the molecular sieve raw powder is 1: 10.
the anti-cracking agent comprises the following components in parts by weight: 36 parts of glass fiber powder and 20 parts of lignin fiber powder.
The etherified starch is hydroxypropyl starch.
Example six:
the preparation method of the reinforced adhesive comprises the following components:
(1) mixing the acidolysis starch and the anti-cracking agent in a mixer at the rotating speed of 600 revolutions per minute for 20 min;
(2) and (2) adding nano aluminum oxide and nano silicon dioxide into the mixture obtained in the step (1), mixing for 1min, adding etherified starch, and continuously mixing for 23min to obtain the reinforced adhesive.
Example seven:
a method for preparing an enhanced molecular sieve comprises the following steps:
(1) putting the molecular sieve raw powder, the clay and the reinforced adhesive into a mixer, stirring for 45min at the rotating speed of 900 revolutions per minute, and fully mixing to obtain premixed powder;
(2) putting the premixed powder into a ball forming mill, rotating the ball forming mill at the rotating speed of 22 revolutions per minute, spraying water mist into the premixed powder at the speed of 0.5m2/S, and acting for 5 hours to obtain a 3A type prefabricated ball particle;
(3) putting the prefabricated pellets into a low-temperature dehumidifier, and removing 20% of water by mass at the temperature of 200 ℃;
(4) and (4) putting the prefabricated pellets in the step (3) into a high-temperature activating machine, and activating at 520 ℃ to obtain the molecular sieve with the water content of 6% in parts by mass.
Comparative example one:
compared with the first embodiment, the molecular sieve raw powder in the raw material is 50 parts, the clay is 45 parts, and the preparation method refers to the sixth embodiment and the seventh embodiment.
Comparative example two:
compared with the first embodiment, the molecular sieve raw powder in the raw material is 50 parts, the clay is 60 parts, and the preparation method refers to the sixth embodiment and the seventh embodiment.
Comparative example three:
compared with the first embodiment, the molecular sieve raw powder in the raw material is 50 parts, the clay is 50 parts, and the preparation method refers to the sixth embodiment and the seventh embodiment.
Comparative example four:
in contrast to example one, no reinforcing binder was added and the preparation method was referenced to example six and example seven.
Comparative example five:
compared with the sixth embodiment, the reinforced adhesive is prepared by the following steps: all raw materials were mixed at once and mixed at 500 rpm for 50 min.
Comparative example six:
a method for preparing an enhanced molecular sieve comprises the following steps:
(1) putting the molecular sieve raw powder, the clay and the reinforced adhesive into a mixer, stirring for 40min at the rotating speed of 700 revolutions per minute, and fully mixing to obtain premixed powder;
(2) putting the premixed powder into a ball forming mill, rotating the ball forming mill at the rotating speed of 15 revolutions per minute, and spraying water mist into the premixed powder at the speed of 0.3m2/S to obtain a prefabricated ball particle with a specified diameter;
(3) putting the prefabricated pellets into a low-temperature dehumidifier, and removing 16% of water by mass at the temperature of 150 ℃;
and (4) putting the prefabricated pellets in the step (3) into a high-temperature activating machine, and activating at 450 ℃ to obtain the molecular sieve with the water content of 9% in parts by mass.
Comparative example seven:
a method for preparing an enhanced molecular sieve comprises the following steps:
(1) putting the molecular sieve raw powder, the clay and the reinforced adhesive into a mixer, stirring for 40min at the rotating speed of 1000 revolutions per minute, and fully mixing to obtain premixed powder;
(2) putting the premixed powder into a ball forming mill, rotating the ball forming mill at the rotating speed of 25 revolutions per minute, and spraying water mist into the premixed powder at the speed of 0.82/S to obtain a prefabricated ball particle with a specified diameter;
(3) putting the prefabricated pellets into a low-temperature dehumidifier, and removing 25% of water by mass at the temperature of 250 ℃;
(4) and (4) putting the prefabricated pellets in the step (3) into a high-temperature activating machine, and activating at 600 ℃ to obtain the molecular sieve with the water content of 3% in parts by mass.
Comparative example eight:
compared with the first example, the acidolysis starch in the reinforcing adhesive is replaced by the same amount of etherified starch, and the preparation method refers to the sixth example and the seventh example.
Comparative example nine:
the replacement of the etherified starch in the reinforcing binder by an equivalent amount of acid-thinned starch as compared to example one is done in accordance with examples six and seven.
Comparative example ten:
compared with the first embodiment, the anti-cracking agent is not added into the reinforced adhesive, and the preparation method refers to the sixth embodiment and the seventh embodiment.
Comparative example eleven:
compared with the first embodiment, the etherified starch in the reinforced adhesive is carboxymethyl starch, and the preparation method refers to the sixth embodiment and the seventh embodiment.
Comparative example twelve:
compared with the first embodiment, the clay is attapulgite, and the ratio of the particle size of the attapulgite to the particle size of the molecular sieve raw powder is 1: 15, preparation method according to example six and example seven.
Comparative example thirteen:
compared with the first embodiment, the clay is attapulgite, and the ratio of the particle size of the attapulgite to the particle size of the molecular sieve raw powder is 1: reference is made to example six and example seven for the preparation thereof.
Comparative example fourteen:
compared with the first embodiment, the lignin fiber powder in the cracking resistance agent is changed into the glass fiber powder with equal weight parts.
And (3) performance detection:
the invention firstly prepares a reinforced adhesive by the preparation method of the sixth embodiment and the formula of the first embodiment to the fifth embodiment, then prepares a 3A type molecular sieve by the preparation method of the seventh embodiment and the formula of the first embodiment to the fifth embodiment, simultaneously prepares a first comparative example to a fourteenth comparative example, and then tests the appearance, the abrasion rate, the crushing resistance, the static water adsorption quantity, the static nitrogen adsorption quantity and the powder falling degree of the molecular sieve according to the test method specified in GB/T10504-2017(3A molecular sieve), and the results are as follows.
TABLE 1
TABLE 2
TABLE 3
According to the detection result, the molecular sieve has good use performance under the condition of the component proportion and the preparation method, and the corresponding type of molecular sieve is directly prepared by adopting the corresponding molecular sieve raw powder.
The present embodiment is only for explaining the present invention, and it is not limited to the present invention, and those skilled in the art can make modifications of the present embodiment without inventive contribution as needed after reading the present specification, but all of them are protected by patent law within the scope of the claims of the present invention.