Preparation method of alumina ball with mesopores and high specific surface area
阅读说明：本技术 具有介孔的高比表面积氧化铝球的制备方法 (Preparation method of alumina ball with mesopores and high specific surface area ) 是由 于如军 王泽尧 彭程 石淋淋 姚风浩 陈艳艳 山书锋 于 2021-08-13 设计创作，主要内容包括：本发明属于氧化铝球制备技术领域,具体的涉及一种具有介孔的高比表面积氧化铝球的制备方法。向盛有球种的成球盘内喷洒木质素磺酸钠溶液,成球盘不断旋转的同时添加ρ-氧化铝快脱粉成球,成球完成后,将球粒过筛；将上述制备得到的氧化铝球首先于50-100℃老化12-48h,然后在100-150℃干燥1-6h；最后在氮气气氛下焙烧,制备得到具有介孔的高比表面积氧化铝球。本发明所述的具有介孔的高比表面积氧化铝球的制备方法,操作简单,易实现,老化条件易于达到,干燥温度低,只在氮气气氛下一次焙烧,不需要氧气气氛下加热,设备要求低,易于产业化推广生产。(The invention belongs to the technical field of preparation of alumina spheres, and particularly relates to a preparation method of an alumina sphere with a mesoporous and high specific surface area. Spraying sodium lignosulfonate solution into a balling disc containing the ball seeds, continuously rotating the balling disc while adding rho-alumina quick-release powder to form balls, and sieving the balls after the balling is finished; the prepared alumina ball is firstly aged for 12-48h at 50-100 ℃, and then dried for 1-6h at 100-150 ℃; and finally, roasting in a nitrogen atmosphere to prepare the mesoporous alumina ball with high specific surface area. The preparation method of the mesoporous alumina ball with high specific surface area is simple to operate, easy to realize, easy to reach aging conditions, low in drying temperature, low in equipment requirement and easy for industrial popularization and production, and only needs to be roasted once in a nitrogen atmosphere without being heated in an oxygen atmosphere.)
1. A preparation method of alumina spheres with mesopores and high specific surface area is characterized in that: the method comprises the following steps:
(1) spraying sodium lignosulfonate solution into a balling disc containing the ball seeds, continuously rotating the balling disc while adding rho-alumina quick-release powder to form balls, and sieving the balls after the balling is finished;
(2) aging the alumina ball prepared in the step (1) at 50-100 ℃ for 12-48h, and then drying at 100-150 ℃ for 1-6 h;
(3) and finally, roasting in a nitrogen atmosphere to prepare the mesoporous alumina ball with high specific surface area.
2. The method for preparing the alumina spheres with the mesoporous and the high specific surface area according to claim 1, wherein the method comprises the following steps: the particle size of the rho-alumina quick-release powder in the step (1) is 35-45 microns; wherein the rho-alumina content is more than or equal to 70-90 percent, and the specific surface area is 220-230m2/g。
3. The method for preparing the alumina spheres with the mesoporous and the high specific surface area according to claim 1, wherein the method comprises the following steps: balling in the step (1), wherein the ball seeds are alumina green balls with the diameter of less than 0.5 mm; the mass ratio of the ball seeds to the rho-alumina quick-release powder is 0.03-0.1; the rotating speed of the balling disc is 10-15 r/min; after the preparation is finished, the mixture is sieved by a 4-7-mesh sieve, the sieved substance is reserved as a ball seed for next ball forming, and the sieve residue is used for aging, drying and roasting to prepare the alumina ball with the mesoporous and the high specific surface area.
4. The method for preparing the alumina spheres with the mesoporous and the high specific surface area according to claim 1, wherein the method comprises the following steps: the concentration of the sodium lignosulfonate solution sprayed in the step (1) is 5-20 wt%, and the solvent is water.
5. The method for preparing the alumina spheres with the mesoporous and the high specific surface area according to claim 1, wherein the method comprises the following steps: the mass of the sodium lignosulfonate solution sprayed in the step (1) accounts for 20-50% of the mass of the rho-alumina quick-release powder.
6. The method for preparing the alumina spheres with the mesoporous and the high specific surface area according to claim 1, wherein the method comprises the following steps: the roasting temperature in the step (3) is 300-600 ℃.
7. The method for preparing the alumina spheres with the mesoporous and the high specific surface area according to claim 1, wherein the method comprises the following steps: the roasting in the step (3) is carried out by heating to 300-600 ℃ at the heating rate of 1.5-1.7 ℃/min, preserving the heat for 5-7h, and then cooling to room temperature at the rate of 1.5-2.0 ℃/min, thus obtaining the alumina ball with mesoporous and high specific surface area.
Technical Field
The invention belongs to the technical field of preparation of alumina spheres, and particularly relates to a preparation method of an alumina sphere with a mesoporous and high specific surface area.
Background
The activated alumina is used as a good hydrogenation catalytic carrier material and has wide application in the oil refining industry. In practical industrial catalytic application, besides reaction active pores with proper size (5nm-20nm), a part of macropores (more than 100 nm) are also needed to be used as efficient macromolecular mass transfer pore channels.
For the macropore control aspect of activated alumina, the main methods at present are: (1) a pH value swing method; (2) pore-expanding agent method; (3) template method. The disadvantages of the method are limited hole expanding capability, the obtained macropores mainly come from crystal grain interstitial pores, limited macropore aperture, larger spatial distribution randomness of the macropores, weak three-dimensional connectivity of the pores and the like. These deficiencies result in certain limitations on the mass transfer efficiency of macromolecular materials in catalytic applications.
The existing techniques for synthesizing the dual-channel aluminum oxide all use aluminum salt solution and additives (carbon black, alkali liquor, ammonium salt, etc.) for ultrasonic treatment, and need to perform heat treatment in oxygen atmosphere. The technical difficulty is high, the operation is complex, the cost is high, and the period is long. Therefore, it is very practical to research a novel, especially cheap and efficient preparation method of the alumina ball with high specific surface area and mesoporous.
Disclosure of Invention
The purpose of the invention is: provides a preparation method of alumina spheres with mesopores and high specific surface area. The preparation method is simple to operate, easy to realize and low in requirement on preparation equipment.
The preparation method of the mesoporous alumina ball with high specific surface area comprises the following steps:
(1) spraying sodium lignosulfonate solution into a balling disc containing the ball seeds, continuously rotating the balling disc while adding rho-alumina quick-release powder to form balls, and sieving the balls after the balling is finished;
(2) aging the alumina ball prepared in the step (1) at 50-100 ℃ for 12-48h, and then drying at 100-150 ℃ for 1-6 h;
(3) and finally, roasting in a nitrogen atmosphere to prepare the mesoporous alumina ball with high specific surface area.
Wherein:
the particle size of the rho-alumina quick-release powder in the step (1) is 35-45 microns; wherein the rho-alumina content is more than or equal to 70-90 percent, and the specific surface area is 220-230m2/g。
Balling in the step (1), wherein the ball seeds are alumina green balls with the diameter of less than 0.5 mm; the mass ratio of the ball seeds to the rho-alumina quick-release powder is 0.03-0.1; the rotating speed of the balling disc is 10-15 r/min; after the preparation is finished, the mixture is sieved by a 4-7-mesh sieve, the sieved substance is reserved as a ball seed for next ball forming, and the sieve residue is used for aging, drying and roasting to prepare the alumina ball with the mesoporous and the high specific surface area.
The mechanism of the balling process in the step (1) is as follows: spraying solution into a balling disk containing a proper amount of ball seeds in advance, continuously rotating the balling disk, simultaneously supplementing rho-alumina quick-release powder, utilizing sodium lignosulfonate solution to adhere the rho-alumina quick-release powder to the ball seeds, gradually growing up the ball seeds due to gravity and hydration and having certain strength, after balling is finished, sieving the ball seeds to obtain alumina balls with proper grain size, and remaining the alumina balls as the ball seeds of next balling.
The concentration of the sodium lignosulfonate solution sprayed in the step (1) is 5-20 wt%, and the solvent is water.
The mass of the sodium lignosulfonate solution sprayed in the step (1) accounts for 20-50% of the mass of the rho-alumina quick-release powder.
The roasting temperature in the step (3) is 300-600 ℃.
The roasting in the step (3) is carried out by heating to 300-600 ℃ at the heating rate of 1.5-1.7 ℃/min, preserving the heat for 5-7h, and then cooling to room temperature at the rate of 1.5-2.0 ℃/min, thus obtaining the alumina ball with mesoporous and high specific surface area.
The sodium lignosulfonate changes the electronegativity of the surface of the alumina during balling, improves the water content and efficiency of quick powder removal, reduces cavities and entrainment, and is combusted in the later roasting process to leave cavities (10-100 nanometer mesopores) to improve the adsorption and desorption efficiency of the alumina balls and prolong the service life of finished alumina balls.
Compared with the prior art, the invention has the following beneficial effects:
(1) according to the preparation method of the mesoporous alumina ball with the high specific surface area, the sodium lignosulfonate aqueous solution is used for balling, and the finished product can be obtained by roasting in a nitrogen atmosphere after aging treatment.
(2) The preparation method of the mesoporous alumina ball with high specific surface area is simple to operate, easy to realize, easy to reach aging conditions, low in drying temperature, low in equipment requirement and easy for industrial popularization and production, and only needs to be roasted once in a nitrogen atmosphere without being heated in an oxygen atmosphere.
Detailed Description
The present invention is further described below with reference to examples.
Example 1
The preparation method of the alumina sphere with mesoporous and high specific surface area described in embodiment 1 comprises the following steps:
(1) spraying sodium lignosulfonate solution into a balling disc containing the ball seeds, continuously rotating the balling disc while adding rho-alumina quick-release powder to form balls, and sieving the balls after the balling is finished;
(2) aging the alumina ball prepared in the step (1) at 100 ℃ for 24h, and then drying at 150 ℃ for 3 h;
(3) and finally, roasting in a nitrogen atmosphere to prepare the mesoporous alumina ball with high specific surface area.
Wherein:
the particle size of the rho-alumina quick-release powder in the step (1) is 40 microns; wherein the content of rho-alumina is 85 percent, and the specific surface area is 225m2/g。
Balling in the step (1), wherein the ball seeds are alumina green balls with the diameter of less than 0.5 mm; the mass ratio of the ball seeds to the rho-alumina quick-release powder is 0.05; the rotating speed of the balling disc is 12 r/min; after the preparation is finished, sieving the mixture by a 4-mesh sieve and then by a 7-mesh sieve to obtain alumina balls with the particle size of 3-5 mm; the screen underflow is reserved as the ball seed for next ball forming, and the screen overflow is used for aging, drying and roasting to prepare the alumina ball with mesoporous and high specific surface area.
The mechanism of the balling process in the step (1) is as follows: spraying solution into a balling disk containing a proper amount of ball seeds in advance, continuously rotating the balling disk, simultaneously supplementing rho-alumina quick-release powder, utilizing sodium lignosulfonate solution to adhere the rho-alumina quick-release powder to the ball seeds, gradually growing up the ball seeds due to gravity and hydration and having certain strength, after balling is finished, sieving the ball seeds to obtain alumina balls with proper grain size, and remaining the alumina balls as the ball seeds of next balling.
The concentration of the sprayed sodium lignosulfonate solution in the step (1) is 18 wt%, and the solvent is water.
The mass of the sodium lignosulfonate solution sprayed in the step (1) accounts for 30% of the mass of the rho-alumina quick-release powder.
The roasting temperature in the step (3) is 350 ℃.
And (3) heating to 350 ℃ at the heating rate of 1.6 ℃/min, preserving the heat for 5h, and then cooling to room temperature at the speed of 1.5 ℃/min to prepare the alumina ball with the mesoporous and high specific surface area.
The sodium lignosulfonate changes the electronegativity of the surface of the alumina during the balling, improves the water and efficiency of quick powder removal, reduces cavities and entrainment, and burns in the later roasting process to leave the cavities to improve the adsorption and desorption efficiency of the alumina balls and prolong the service life of the finished alumina balls.
The alumina balls prepared in example 1 were subjected to the performance test, and the results are shown in table 1 below:
table 1 results of performance test of alumina balls prepared in example 1
Specific surface area
Maximum pore diameter
Most probable aperture
Pore volume
Strength of
320m2/g
130nm
4nm
0.8cm3/g
209N/grain
Example 2
The preparation method of the alumina sphere with mesoporous and high specific surface area described in embodiment 2 comprises the following steps:
(1) spraying sodium lignosulfonate solution into a balling disc containing the ball seeds, continuously rotating the balling disc while adding rho-alumina quick-release powder to form balls, and sieving the balls after the balling is finished;
(2) aging the alumina ball prepared in the step (1) at 50 ℃ for 48h, and then drying at 100 ℃ for 6 h;
(3) and finally, roasting in a nitrogen atmosphere to prepare the mesoporous alumina ball with high specific surface area.
Wherein:
the quick removal of the rho-alumina in the step (1)The particle size of the powder is 40 microns; wherein the content of rho-alumina is 85 percent, and the specific surface area is 225m2/g。
Balling in the step (1), wherein the ball seeds are alumina green balls with the diameter of less than 0.5 mm; the mass ratio of the ball seeds to the rho-alumina quick-release powder is 0.03; the rotating speed of the balling disc is 15 r/min; after the preparation is finished, sieving the mixture by a 4-mesh sieve and then by a 7-mesh sieve to obtain alumina balls with the particle size of 3-5 mm; the screen underflow is reserved as the ball seed for next ball forming, and the screen overflow is used for aging, drying and roasting to prepare the alumina ball with mesoporous and high specific surface area.
The mechanism of the balling process in the step (1) is as follows: spraying solution into a balling disk containing a proper amount of ball seeds in advance, continuously rotating the balling disk, simultaneously supplementing rho-alumina quick-release powder, utilizing sodium lignosulfonate solution to adhere the rho-alumina quick-release powder to the ball seeds, gradually growing up the ball seeds due to gravity and hydration and having certain strength, after balling is finished, sieving the ball seeds to obtain alumina balls with proper grain size, and remaining the alumina balls as the ball seeds of next balling.
The concentration of the sprayed sodium lignosulfonate solution in the step (1) is 5 wt%, and the solvent is water.
The mass of the sodium lignosulfonate solution sprayed in the step (1) accounts for 20% of the mass of the rho-alumina quick-release powder.
The roasting temperature in the step (3) is 500 ℃.
And (3) heating to 500 ℃ at the heating rate of 1.5 ℃/min, keeping the temperature for 6h, and then cooling to room temperature at the speed of 1.8 ℃/min to prepare the alumina ball with the mesoporous and high specific surface area.
The sodium lignosulfonate changes the electronegativity of the surface of the alumina during the balling, improves the water and efficiency of quick powder removal, reduces cavities and entrainment, and burns in the later roasting process to leave the cavities to improve the adsorption and desorption efficiency of the alumina balls and prolong the service life of the finished alumina balls.
The alumina balls prepared in example 2 were subjected to the performance test, and the results are shown in table 2 below:
table 2 results of performance test of alumina balls prepared in example 2
Specific surface area
Maximum pore diameter
Most probable aperture
Pore volume
Strength of
300m2/g
100nm
5nm
0.5cm3/g
191N/granule
Example 3
The preparation method of the alumina sphere with mesoporous and high specific surface area described in embodiment 3 comprises the following steps:
(1) spraying sodium lignosulfonate solution into a balling disc containing the ball seeds, continuously rotating the balling disc while adding rho-alumina quick-release powder to form balls, and sieving the balls after the balling is finished;
(2) aging the alumina ball prepared in the step (1) at 80 ℃ for 36h, and then drying at 120 ℃ for 4 h;
(3) and finally, roasting in a nitrogen atmosphere to prepare the mesoporous alumina ball with high specific surface area.
Wherein:
the particle size of the rho-alumina quick-release powder in the step (1) is 40 microns; wherein the content of rho-alumina85% of the total amount of the powder, and the specific surface area of the powder was 225m2/g。
Balling in the step (1), wherein the ball seeds are alumina green balls with the diameter of less than 0.5 mm; the mass ratio of the ball seeds to the rho-alumina quick-release powder is 0.1; the rotating speed of the balling disc is 15 r/min; after the preparation is finished, sieving the mixture by a 4-mesh sieve and then by a 7-mesh sieve to obtain alumina balls with the particle size of 3-5 mm; the screen underflow is reserved as the ball seed for next ball forming, and the screen overflow is used for aging, drying and roasting to prepare the alumina ball with mesoporous and high specific surface area.
The mechanism of the balling process in the step (1) is as follows: spraying solution into a balling disk containing a proper amount of ball seeds in advance, continuously rotating the balling disk, simultaneously supplementing rho-alumina quick-release powder, utilizing sodium lignosulfonate solution to adhere the rho-alumina quick-release powder to the ball seeds, gradually growing up the ball seeds due to gravity and hydration and having certain strength, after balling is finished, sieving the ball seeds to obtain alumina balls with proper grain size, and remaining the alumina balls as the ball seeds of next balling.
The concentration of the sprayed sodium lignosulfonate solution in the step (1) is 20 wt%, and the solvent is water.
The mass of the sodium lignosulfonate solution sprayed in the step (1) accounts for 50% of the mass of the rho-alumina quick-release powder.
The roasting temperature in the step (3) is 600 ℃.
And (3) heating to 600 ℃ at the heating rate of 1.7 ℃/min, preserving the heat for 5h, and then cooling to room temperature at the speed of 2.0 ℃/min to prepare the alumina ball with the mesoporous and high specific surface area.
The sodium lignosulfonate changes the electronegativity of the surface of the alumina during the balling, improves the water and efficiency of quick powder removal, reduces cavities and entrainment, and burns in the later roasting process to leave the cavities to improve the adsorption and desorption efficiency of the alumina balls and prolong the service life of the finished alumina balls.
The alumina balls prepared in example 3 were subjected to the performance test, and the results are shown in the following table 3:
table 3 results of performance test of alumina balls prepared in example 3
Specific surface area
Maximum pore diameter
Most probable aperture
Pore volume
Strength of
300m2/g
100nm
4nm
0.7cm3/g
205N/granule
Comparative example 1
The preparation method of the alumina sphere with the mesoporous and the high specific surface area as the comparative example 1 comprises the following steps:
(1) spraying water into a balling disc containing the ball seeds, continuously rotating the balling disc while adding rho-alumina quick-release powder to form balls, and sieving the balls after the balling is finished;
(2) aging the alumina ball prepared in the step (1) at 100 ℃ for 24h, and then drying at 150 ℃ for 3 h;
(3) and finally, roasting in a nitrogen atmosphere to prepare the mesoporous alumina ball with high specific surface area.
Wherein:
the particle size of the rho-alumina quick-release powder in the step (1) is 40 microns; wherein the content of rho-alumina is 85 percent, and the specific surface area is 225m2/g。
Balling in the step (1), wherein the ball seeds are alumina green balls with the diameter of less than 0.5 mm; the mass ratio of the ball seeds to the rho-alumina quick-release powder is 0.05; the rotating speed of the balling disc is 12 r/min; after the preparation is finished, sieving the mixture by a 4-mesh sieve and then by a 7-mesh sieve to obtain alumina balls with the particle size of 3-5 mm; the screen underflow is reserved as the next ball seed for balling, and the screen overflow is used for aging, drying and roasting to prepare the macroporous alumina balls.
The mechanism of the balling process in the step (1) is as follows: spraying water into a balling disk which contains a proper amount of ball seeds in advance, continuously rotating the balling disk, simultaneously replenishing rho-alumina quick-release powder, adhering the rho-alumina quick-release powder to the ball seeds by using the water, gradually growing the ball seeds and having certain strength due to gravity and hydration, after balling is finished, sieving the ball seeds to obtain alumina balls with proper grain size, and remaining particles with small grain size as the ball seeds of next balling.
The mass of the sprayed water in the step (1) accounts for 30% of the mass of the rho-alumina quick-release powder.
The roasting temperature in the step (3) is 350 ℃.
And (3) heating to 350 ℃ at the heating rate of 1.6 ℃/min, preserving the heat for 5h, and then cooling to room temperature at the speed of 1.5 ℃/min to prepare the alumina ball with the mesoporous and high specific surface area.
The alumina balls prepared in comparative example 1 were subjected to performance tests, and the results are shown in table 4 below:
table 4 results of performance test of alumina balls prepared in comparative example 1
Specific surface area
Maximum pore diameter
Most probablySeveral apertures
Pore volume
Strength of
300m2/g
20nm
6nm
0.4cm3/g
200N/granule