CN115784281A - Nano gamma-Al 2 O 3 Method for producing particles - Google Patents
Nano gamma-Al 2 O 3 Method for producing particles Download PDFInfo
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- 239000002245 particle Substances 0.000 title claims abstract description 54
- 229910018072 Al 2 O 3 Inorganic materials 0.000 title claims abstract description 20
- 238000004519 manufacturing process Methods 0.000 title claims description 7
- 239000002904 solvent Substances 0.000 claims abstract description 26
- 239000011259 mixed solution Substances 0.000 claims abstract description 20
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims abstract description 18
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 claims abstract description 16
- 239000002253 acid Substances 0.000 claims abstract description 15
- 238000002360 preparation method Methods 0.000 claims abstract description 15
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- 238000006243 chemical reaction Methods 0.000 claims description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 15
- 238000000034 method Methods 0.000 claims description 11
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 claims description 9
- BNGXYYYYKUGPPF-UHFFFAOYSA-M (3-methylphenyl)methyl-triphenylphosphanium;chloride Chemical compound [Cl-].CC1=CC=CC(C[P+](C=2C=CC=CC=2)(C=2C=CC=CC=2)C=2C=CC=CC=2)=C1 BNGXYYYYKUGPPF-UHFFFAOYSA-M 0.000 claims description 6
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- WRIDQFICGBMAFQ-UHFFFAOYSA-N (E)-8-Octadecenoic acid Natural products CCCCCCCCCC=CCCCCCCC(O)=O WRIDQFICGBMAFQ-UHFFFAOYSA-N 0.000 claims description 4
- LQJBNNIYVWPHFW-UHFFFAOYSA-N 20:1omega9c fatty acid Natural products CCCCCCCCCCC=CCCCCCCCC(O)=O LQJBNNIYVWPHFW-UHFFFAOYSA-N 0.000 claims description 4
- QSBYPNXLFMSGKH-UHFFFAOYSA-N 9-Heptadecensaeure Natural products CCCCCCCC=CCCCCCCCC(O)=O QSBYPNXLFMSGKH-UHFFFAOYSA-N 0.000 claims description 4
- 239000005642 Oleic acid Substances 0.000 claims description 4
- ZQPPMHVWECSIRJ-UHFFFAOYSA-N Oleic acid Natural products CCCCCCCCC=CCCCCCCCC(O)=O ZQPPMHVWECSIRJ-UHFFFAOYSA-N 0.000 claims description 4
- SMZOGRDCAXLAAR-UHFFFAOYSA-N aluminium isopropoxide Chemical compound [Al+3].CC(C)[O-].CC(C)[O-].CC(C)[O-] SMZOGRDCAXLAAR-UHFFFAOYSA-N 0.000 claims description 4
- -1 aluminum ions Chemical class 0.000 claims description 4
- QXJSBBXBKPUZAA-UHFFFAOYSA-N isooleic acid Natural products CCCCCCCC=CCCCCCCCCC(O)=O QXJSBBXBKPUZAA-UHFFFAOYSA-N 0.000 claims description 4
- ZQPPMHVWECSIRJ-KTKRTIGZSA-N oleic acid group Chemical group C(CCCCCCC\C=C/CCCCCCCC)(=O)O ZQPPMHVWECSIRJ-KTKRTIGZSA-N 0.000 claims description 4
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 3
- HDYRYUINDGQKMC-UHFFFAOYSA-M acetyloxyaluminum;dihydrate Chemical compound O.O.CC(=O)O[Al] HDYRYUINDGQKMC-UHFFFAOYSA-M 0.000 claims description 3
- 229940009827 aluminum acetate Drugs 0.000 claims description 3
- 239000000498 cooling water Substances 0.000 claims description 3
- 229910017604 nitric acid Inorganic materials 0.000 claims description 3
- 239000003795 chemical substances by application Substances 0.000 claims description 2
- FATBGEAMYMYZAF-KTKRTIGZSA-N oleamide Chemical compound CCCCCCCC\C=C/CCCCCCCC(N)=O FATBGEAMYMYZAF-KTKRTIGZSA-N 0.000 claims description 2
- 239000005456 alcohol based solvent Substances 0.000 claims 2
- FATBGEAMYMYZAF-UHFFFAOYSA-N oleicacidamide-heptaglycolether Natural products CCCCCCCCC=CCCCCCCCC(N)=O FATBGEAMYMYZAF-UHFFFAOYSA-N 0.000 claims 1
- 239000012530 fluid Substances 0.000 abstract description 8
- 238000001308 synthesis method Methods 0.000 abstract description 3
- 239000007788 liquid Substances 0.000 abstract 1
- 239000000463 material Substances 0.000 abstract 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 6
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 4
- 239000013078 crystal Substances 0.000 description 4
- 238000009826 distribution Methods 0.000 description 4
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- 239000002184 metal Substances 0.000 description 4
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 3
- 239000006185 dispersion Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- AFCARXCZXQIEQB-UHFFFAOYSA-N N-[3-oxo-3-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CCNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 AFCARXCZXQIEQB-UHFFFAOYSA-N 0.000 description 2
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical compound Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 description 2
- 239000002585 base Substances 0.000 description 2
- 230000015572 biosynthetic process Effects 0.000 description 2
- 229910001593 boehmite Inorganic materials 0.000 description 2
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- 238000006460 hydrolysis reaction Methods 0.000 description 2
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 2
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- 229910000838 Al alloy Inorganic materials 0.000 description 1
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 1
- 229910002651 NO3 Inorganic materials 0.000 description 1
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 description 1
- 238000003917 TEM image Methods 0.000 description 1
- 238000002441 X-ray diffraction Methods 0.000 description 1
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- 239000003513 alkali Substances 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 1
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- 210000005239 tubule Anatomy 0.000 description 1
Images
Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P20/00—Technologies relating to chemical industry
- Y02P20/50—Improvements relating to the production of bulk chemicals
- Y02P20/54—Improvements relating to the production of bulk chemicals using solvents, e.g. supercritical solvents or ionic liquids
Abstract
The invention discloses a nanometer gamma-Al 2 O 3 A preparation method of particles belongs to the technical field of inorganic nonmetallic materials. Pumping a solvent into one end of a reactor, heating and pressurizing to form a supercritical solvent, pumping a mixed solution of aluminum salt and acid with a certain concentration into the reactor, carrying out hydrothermal reaction with the supercritical solvent to obtain alumina particles, pumping a modifier solution with a certain concentration into the reactor, carrying out surface modification on the alumina particles, carrying out quenching cooling on the modified alumina particles, then feeding the cooled alumina particles into a recovery tank to be collected, and carrying out ultra-high speed centrifugation on liquid in the recovery tank to obtain gamma-Al 2 O 3 Particles. The invention adopts the supercritical fluid synthesis method, the preparation process is convenient and easy to control, and the prepared gamma-Al 2 O 3 The particle appearance is sphere-like, the crystallinity is high, the dispersibility is good, and the particle size is small and uniform.
Description
Technical Field
The invention relates to the technical field of inorganic non-metallic materials, in particular to nano gamma-Al 2 O 3 A method for preparing the particles.
Background
γ-Al 2 O 3 Is a transition state of a common alumina, and is generally formed by aluminum hydroxide and the like at a low temperature (500 to 700 ℃) and mostly forms gamma-Al 2 O 3 Is the most common transition alumina, belongs to a spinel structure, and does not exist in nature. gamma-Al 2 O 3 The preparation process is simple, the grain diameter of the gamma-phase particles is small, but the gamma-phase particles have huge specific surface area which can reach 1000m 2 More than g. The gamma phase particle is mainly used as a carrier of a catalyst and is used in the fields of petrochemical industry, environmental protection and the like. However, when the water content is too high or the temperature is too high, the γ -phase particles grow, sinter, and may be transformed into a stable α -phase, thereby losing a large specific surface area thereof, resulting in the failure of the catalyst. Therefore, increasing the stability of the γ phase under high temperature conditions is one of the key problems to be solved. At present, a small amount of substances such as rare earth elements are added into a gamma phase to improve the surface energy of the gamma phase, so that the gamma-Al is effectively inhibited 2 O 3 The phase transformation and sintering occur, and the stability of the specific surface is improved.
At present, gamma-Al 2 O 3 The preparation of (A) is as follows:
1) Preparation of pseudo-boehmite Dan Tuoshui: obtained by pseudo-boehmite Dan Tuoshui, namely, pseudo-boehmite is converted into boehmite at 200 ℃; boehmite is converted into gamma-Al at 450 DEG C 2 O 3 . The pseudo-boehmite is usually prepared by an acid method or an alkali method, acid-base neutralization reaction can be carried out in the reaction process, and harmful gas generated in the acid-base decomposition process can cause harm to the environment and human bodies.
2) Preparing by a sol-gel method: as gamma-Al, an inorganic aluminum salt such as aluminum nitrate, aluminum sulfate, aluminum chloride or the like, or an organic aluminum salt such as aluminum isopropoxide or the like is used 2 O 3 Dissolving the prepared precursor in water or organic solvent, hydrolyzing, polycondensing to form transparent sol, gradually gelatinizing, drying, and heat treating to obtain gamma-Al 2 O 3 . However, the alumina powder produced by this method has a non-uniform particle size distribution, is easily agglomerated, and has a large particle size.
Disclosure of Invention
The invention aims to provide nano gamma-Al 2 O 3 Method for preparing particles to solve one or more technical problems of the prior art, such as gamma-Al 2 O 3 Irregular shape, non-uniform grain diameter and easy agglomeration in the process of preparing the nano powder.
In order to achieve the purpose, the invention provides the following technical scheme: nano gamma-Al 2 O 3 A method for preparing particles comprising the steps of:
1) Pumping the solvent into one end of the reactor, heating and pressurizing to form supercritical solvent;
2) Pumping a mixed solution of aluminum salt and acid with a certain concentration into the reactor, and carrying out hydrothermal reaction on the supercritical solvent and the mixed solution in the reactor in a supercritical state to obtain alumina particles;
3) Pumping a modifier solution with a certain concentration into a reactor, and carrying out surface modification on the alumina particles conveyed by the supercritical solvent;
4) The modified alumina particles enter a recovery tank to be collected after being quenched and cooled along with the supercritical solvent;
5) Ultra-high speed centrifugation is adopted to obtain the nano gamma-Al 2 O 3 。
Preferably, in step 2), the solvent is selected from pure water or an alcohol solvent, and the supercritical solvent is supercritical water or a supercritical alcohol solvent.
Preferably, the aluminum salt is selected from one of aluminum nitrate, aluminum acetate and aluminum isopropoxide, and the acid is selected from one of nitric acid and acetic acid.
Preferably, in the step 2), the solubility of aluminum ions in the mixed solution of the aluminum salt and the acid is between 0.1 and 0.3M, and the concentration ratio of the aluminum salt to the acid is between 7.5 and 15.
Preferably, in the step 2), the reaction temperature of the hydrothermal reaction is 380-450 ℃, and the reaction pressure is 26-30 Mpa.
Preferably, the reaction temperature of the hydrothermal reaction is 420-450 ℃, and the reaction pressure is 28-30 Mpa.
Preferably, in step 3), the modifying agent is selected from oleic acid or oleic acid amide.
Preferably, the solvent, the mixed solution of the aluminum salt and the acid, and the modifier are pumped into the reactor, which is a capillary reactor, by different high-pressure pumps.
Preferably, the quenching in the step 4) is carried out by rapidly cooling the pipe wrapped by cooling water to below 50 ℃.
Preferably, in the step 2), the mixed solution is pumped into the reactor, and then is mixed with the supercritical solvent in the reactor, so that the mixed solution instantly reaches the hydrothermal reaction in a supercritical state.
The invention uses water or alcohol as supercritical solvent, and uses the sharp reduction of the solubility of metal salt in supercritical fluid under supercritical state to achieve the purpose of separating out metal oxide. In the reaction process, the metal salt solution reaches a supercritical state at the moment of collision with the high-temperature fluid, wherein the metal salt can form metal oxide and precipitate in the supercritical fluid due to hydrolysis and dehydration reactions, and the nitrate is taken as an example, and the specific reaction is as follows:
M(NO 3 ) x +xH 2 O→M(OH) x +xHNO 3 (1)
M(OH) x →MO x/2 +x/2 H 2 O (2)
because the metal salt has extremely low solubility in the supercritical fluid and high hydrolysis speed, crystal nuclei can be quickly formed and precipitated, and formed crystal grains are fine and uniform in grain diameter, so that the form and the grain diameter of the synthesized oxide can be controlled by changing the pressure and the temperature of the reaction environment.
Further, the invention realizes the precise control of the product size by controlling the saturation degree of aluminum ions in the fine tube reactor, such as by controlling the concentration, flow rate and flow rate ratio of raw materials. In addition, the reaction temperature can be controlled by controlling the flow rate and the ratio thereof, thereby realizing the control of the product phase.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention adopts the supercritical fluid synthesis method, the preparation process is convenient and easy to control, and the preparation method is safe and environment-friendly;
2. the nano-alumina synthesized by the method has high crystallinity and less surface defects, and the supercritical synthesis can more easily obtain smaller size (D50) compared with other preparation methods<20 nm), narrower particle size distribution, and near independent dispersion of gamma-Al 2 O 3 Nanoparticles.
3. The gamma-Al prepared by the invention 2 O 3 The particle product is spherical, strong in crystallinity, good in dispersity, complete in crystal form, small and uniform in particle size.
Drawings
FIG. 1 shows a nano-gamma-Al alloy in accordance with an embodiment of the present invention 2 O 3 A schematic of the preparation of the particles;
FIG. 2 shows the nano-gamma-Al prepared in example 1 of the present invention 2 O 3 XRD pattern of the particles;
FIGS. 3 and 4 show the nano-gamma-Al prepared in example 1 of the present invention 2 O 3 TEM image of the particles, wherein the morphology and dispersion state of the particles are shown in FIG. 3, and FIG. 4 shows the nano-gamma-Al of FIG. 3 2 O 3 The crystal lattice pattern of (4) (electron diffraction pattern in the upper right corner of FIG. 4);
FIG. 5 shows the nano-gamma-Al prepared in example 1 of the present invention 2 O 3 Particle size distribution profile of the particles.
Detailed Description
The following detailed description of the present invention is provided in conjunction with the accompanying drawings, but it should be understood that the scope of the present invention is not limited to the specific embodiments.
Throughout the specification and claims, unless explicitly stated otherwise, the word "comprise", or variations such as "comprises" or "comprising", will be understood to imply the inclusion of a stated element or component but not the exclusion of any other element or component.
The present invention will be described in detail below with reference to specific embodiments shown in the drawings. These embodiments are not intended to limit the present invention, and structural, methodological, or functional changes made by those skilled in the art according to these embodiments are included in the scope of the present invention.
The invention discloses a nano-crystalline gamma-Al 2 O 3 The preparation method of the particles, which adopts a supercritical fluid synthesis method and is shown in the combined figure 1, comprises the following preparation steps:
(1) The pressure of the apparatus is increased by a back pressure valve, and then pure water or an alcohol solvent such as ethanol, isopropyl alcohol, etc. is pumped into the front end of the fine tube reactor by a pulseless high pressure pump P1, and a supercritical state solvent is formed after heating, wherein pure water is exemplified in fig. 1, and the heating includes auxiliary heating and heating furnace heating.
(2) Pumping the prepared mixed solution A of aluminum salt and acid with certain concentration into the middle section of the thin tube reactor through a pulse-free high-pressure pump P2, mixing the mixed solution A with supercritical water conveyed by a high-pressure pump P1 at a first junction S, enabling the mixed solution A to reach a supercritical state instantly, and carrying out hydrothermal reaction to generate alumina particles.
The aluminum salt is selected from one of aluminum nitrate, aluminum acetate, aluminum isopropoxide, etc., and the acid is usually selected from one of nitric acid or acetic acid. The solubility of aluminum ions in the mixed solution A is usually 0.1 to 0.3M, and the ratio of the concentration of aluminum salt to that of aluminum acid is 7.5 to 15. The reaction temperature of the hydrothermal reaction is 380 to 450 ℃, preferably 420 to 450 ℃, the reaction pressure is 26 to 30MPa, preferably 28 to 30MPa, and the flow rate ratio of the high-pressure pump P1 to the high-pressure pump P2 is 10 to 13, preferably 12 to 13. The mixed solution stays in the tubule reactor for 0.5-2 s and then reaches a second intersection point M.
(3) Pumping the prepared modifier solution B with a certain concentration into the rear end of the thin tube reactor through a high-pressure pump P3, vertically colliding with the mixed solution in the step S2 at a second intersection point M to modify the surface of the alumina particles conveyed by the supercritical water, and combining modifier molecules with the alumina particles to play a role in modification and dispersion.
(4) The modified alumina particles continuously flow outwards along with the solution, leave the electric heating furnace and enter a pipeline wrapped by cooling water to be rapidly cooledBut to below 50 c. The cooled reaction solution enters a recovery tank for recovery, and the equipment shown in figure 1 is optionally provided with two recovery tanks and can be switched back and forth to realize continuous synthesis. The recovered reaction liquid is settled by an ultra-high speed centrifuge to obtain the gamma-Al with uniformly dispersed small grain size 2 O 3 The average grain diameter is between 5 and 30nm.
The present invention will be further described with reference to the following specific examples.
Example 1
(1) 500ml of an aqueous solution of aluminum nitrate having a concentration of 0.15mol/L was added to a 1L beaker, and stirred for 30min. Add another 1L beaker with oleic acid alcoholic solution.
(2) The apparatus shown in FIG. 1 was used, and the pressure in the apparatus was adjusted to 30MPa. And filling two 5L beakers with pure water, respectively conveying the pure water in the beakers to the thin tube reactor through a pulse-free high-pressure pump P1 and a pulse-free high-pressure pump P2, wherein the flow rate ratio of the P1 to the P2 is 12, the flow rate of the P2 is 2ml/min, opening the auxiliary heating to enable the temperature of the pure water in the P1 to be higher than 380 ℃, then opening the heating furnace to enable the temperature to reach more than 450 ℃, and simultaneously ensuring that the temperature of an S point at a mixing part of the two tubes is maintained to be higher than 425 ℃.
(3) Replacing pure water supplied by P2 with the raw material solution prepared in (1), maintaining the flow rate and reaction temperature in (2), and beginning to precipitate gamma-Al from aluminum nitrate at the S point 2 O 3 The residence time of the whole reaction section (S-M section in figure 1) is about 0.7S, and the oleic acid molecule is coated on the gamma-Al when passing through the M point 2 O 3 A surface. The coated particles then pass through a cooling conduit with the fluid and into a recovery tank. Collecting the slurry in the recovery tank, centrifuging by an ultra-high speed centrifuge, and drying to obtain gamma-Al 2 O 3 The powder has a particle size of about 10 to 15 nm.
Gamma-Al prepared in this example 2 O 3 The XRD diffraction pattern of the compound is shown in FIG. 2, the TEM pattern is shown in FIGS. 3 and 4, and the particle size distribution diagram is shown in FIG. 5.
Example 2
In contrast to example 1, the flow rate ratio of P1 and P2 (P1/P2 = 13) was changed to change the residence time of the raw material solution in the reaction zone (about 0.5 s), and the rest was equivalent to γ -Al synthesized under the conditions of example 1 2 O 3 The particle size of the sample was about 6.5nm.
Example 3
In contrast, the ion concentration (Al) of the mixed solution A was changed in example 1 3+ Is 0.2M) to increase the ion saturation degree during the reaction, and the rest is equivalent to gamma-Al synthesized under the condition of example 1 2 O 3 The particle size of the sample is about 20 to 30nm.
Comparative example 1
The reaction temperature and the flow rate ratio of P1 and P2 in example 1 were changed as shown in Table 1, and the rest was the same as example 1.
The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. It is not intended to limit the invention to the precise form disclosed, and obviously many modifications and variations are possible in light of the above teaching. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and its practical application to enable one skilled in the art to make and use various exemplary embodiments of the invention and various alternatives and modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims and their equivalents.
Claims (10)
1. Nano gamma-Al 2 O 3 A method for producing particles, characterized by comprising the steps of:
1) Pumping the solvent into one end of the reactor, heating and pressurizing to form supercritical solvent;
2) Pumping a mixed solution of aluminum salt and acid with a certain concentration into the reactor, and carrying out hydrothermal reaction on the supercritical solvent and the mixed solution in the reactor in a supercritical state to obtain alumina particles;
3) Pumping modifier solution with certain concentration into a reactor, and carrying out surface modification on the alumina particles conveyed by the supercritical solvent;
4) The modified alumina particles enter a recovery tank to be collected after being quenched and cooled along with the supercritical solvent;
5) Ultra-high speed centrifugation is adopted to obtain the nano gamma-Al 2 O 3 。
2. The nano gamma-Al of claim 1 2 O 3 The method for preparing particles is characterized in that in the step 2), the solvent is selected from one of pure water or alcohol solvents, and the supercritical solvent is supercritical water or supercritical alcohol solvents.
3. The nano gamma-Al of claim 1 2 O 3 The method for producing particles is characterized in that in step 2), the aluminum salt is one selected from aluminum nitrate, aluminum acetate and aluminum isopropoxide, and the acid is one selected from nitric acid and acetic acid.
4. The nano gamma-Al of claim 1 2 O 3 The method for producing particles is characterized in that in the step 2), the solubility of aluminum ions in the mixed solution of the aluminum salt and the acid is 0.1 to 0.3M, and the concentration ratio of the aluminum salt to the acid is 7.5 to 15.
5. The nano gamma-Al of claim 1 2 O 3 The preparation method of the particles is characterized in that in the step 2), the reaction temperature of the hydrothermal reaction is 380-450 ℃, and the reaction pressure is 26-30 Mpa.
6. The method of claim 5, wherein the nano-gamma-Al is 2 O 3 The preparation method of the particles is characterized in that the reaction temperature of the hydrothermal reaction is 420-450 ℃, and the reaction pressure is 28-30 Mpa.
7. The nano gamma-Al of claim 1 2 O 3 A method for producing particles, characterized in thatIn the step 3), the modifying agent is selected from oleic acid or oleamide.
8. The nano gamma-Al of claim 1 2 O 3 The preparation method of the particles is characterized in that the solvent, the mixed solution of the aluminum salt and the acid and the modifier are respectively pumped into a reactor by different high-pressure pumps, and the reactor is a thin tube reactor.
9. The nano gamma-Al of claim 1 2 O 3 The method for producing particles is characterized in that the quenching cooling in the step 4) is a rapid cooling to 50 ℃ or lower in a pipe wrapped with cooling water.
10. The nano gamma-Al of claim 1 2 O 3 The preparation method of the particles is characterized in that the mixed solution in the step 2) is pumped into the reactor and then is mixed with the supercritical solvent in the reactor to enable the mixed solution to instantly reach the hydrothermal reaction in a supercritical state.
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Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008137884A (en) * | 2006-11-06 | 2008-06-19 | National Institute Of Advanced Industrial & Technology | Alumina micro particles and method of manufacturing alumina sol |
| JP2012197195A (en) * | 2011-03-18 | 2012-10-18 | Tohoku Univ | Method for modification-treating metal oxide surface in supercritical water |
| CN107278198A (en) * | 2014-12-23 | 2017-10-20 | 埃西勒国际通用光学公司 | A kind of continuous current method for being used to manufacture the metal oxide nanoparticles that surface is modified by supercritical solvent thermal synthesis |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2008137884A (en) * | 2006-11-06 | 2008-06-19 | National Institute Of Advanced Industrial & Technology | Alumina micro particles and method of manufacturing alumina sol |
| JP2012197195A (en) * | 2011-03-18 | 2012-10-18 | Tohoku Univ | Method for modification-treating metal oxide surface in supercritical water |
| CN107278198A (en) * | 2014-12-23 | 2017-10-20 | 埃西勒国际通用光学公司 | A kind of continuous current method for being used to manufacture the metal oxide nanoparticles that surface is modified by supercritical solvent thermal synthesis |
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