CN117285060A - Preparation method of high-wear-resistance microspherical alumina - Google Patents
Preparation method of high-wear-resistance microspherical alumina Download PDFInfo
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- CN117285060A CN117285060A CN202311158596.3A CN202311158596A CN117285060A CN 117285060 A CN117285060 A CN 117285060A CN 202311158596 A CN202311158596 A CN 202311158596A CN 117285060 A CN117285060 A CN 117285060A
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- boehmite
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- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 title claims abstract description 40
- 238000002360 preparation method Methods 0.000 title claims abstract description 13
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 49
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 claims abstract description 38
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 33
- 239000012065 filter cake Substances 0.000 claims abstract description 31
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 20
- 239000008367 deionised water Substances 0.000 claims abstract description 17
- 229910021641 deionized water Inorganic materials 0.000 claims abstract description 17
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 16
- 238000003756 stirring Methods 0.000 claims abstract description 15
- 239000002245 particle Substances 0.000 claims abstract description 13
- 239000002002 slurry Substances 0.000 claims abstract description 13
- 230000032683 aging Effects 0.000 claims abstract description 12
- 239000012670 alkaline solution Substances 0.000 claims abstract description 10
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical class [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 claims abstract description 10
- 238000009718 spray deposition Methods 0.000 claims abstract description 9
- 230000007935 neutral effect Effects 0.000 claims abstract description 7
- 238000005406 washing Methods 0.000 claims abstract description 7
- 239000000706 filtrate Substances 0.000 claims abstract description 6
- 238000010438 heat treatment Methods 0.000 claims abstract description 6
- 150000007522 mineralic acids Chemical class 0.000 claims abstract description 6
- 230000002194 synthesizing effect Effects 0.000 claims abstract description 6
- 150000004645 aluminates Chemical class 0.000 claims abstract description 5
- 238000001035 drying Methods 0.000 claims abstract description 5
- 238000012986 modification Methods 0.000 claims abstract description 5
- 230000004048 modification Effects 0.000 claims abstract description 5
- 238000004537 pulping Methods 0.000 claims abstract description 5
- 239000007864 aqueous solution Substances 0.000 claims description 20
- 238000000034 method Methods 0.000 claims description 18
- VKYKSIONXSXAKP-UHFFFAOYSA-N hexamethylenetetramine Chemical compound C1N(C2)CN3CN1CN2C3 VKYKSIONXSXAKP-UHFFFAOYSA-N 0.000 claims description 10
- 239000011734 sodium Substances 0.000 claims description 10
- 229910052708 sodium Inorganic materials 0.000 claims description 10
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical group C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 9
- 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 claims description 8
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims description 7
- 229910017604 nitric acid Inorganic materials 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 6
- 239000004312 hexamethylene tetramine Substances 0.000 claims description 5
- 235000010299 hexamethylene tetramine Nutrition 0.000 claims description 5
- VSCWAEJMTAWNJL-UHFFFAOYSA-K aluminium trichloride Chemical group Cl[Al](Cl)Cl VSCWAEJMTAWNJL-UHFFFAOYSA-K 0.000 claims description 4
- 239000000126 substance Substances 0.000 claims description 4
- XSQUKJJJFZCRTK-UHFFFAOYSA-N Urea Chemical compound NC(N)=O XSQUKJJJFZCRTK-UHFFFAOYSA-N 0.000 claims description 3
- 239000004202 carbamide Substances 0.000 claims description 3
- 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 2
- 238000005299 abrasion Methods 0.000 description 11
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 8
- 230000000052 comparative effect Effects 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- 239000004005 microsphere Substances 0.000 description 7
- 239000003054 catalyst Substances 0.000 description 5
- 238000005303 weighing Methods 0.000 description 4
- 239000002253 acid Substances 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 239000000047 product Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- QGZKDVFQNNGYKY-UHFFFAOYSA-N Ammonia Chemical compound N QGZKDVFQNNGYKY-UHFFFAOYSA-N 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- GOOHAUXETOMSMM-UHFFFAOYSA-N Propylene oxide Chemical compound CC1CO1 GOOHAUXETOMSMM-UHFFFAOYSA-N 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- 239000013067 intermediate product Substances 0.000 description 2
- 229940057995 liquid paraffin Drugs 0.000 description 2
- 239000000203 mixture Substances 0.000 description 2
- 238000001935 peptisation Methods 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 239000004094 surface-active agent Substances 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- 229920002134 Carboxymethyl cellulose Polymers 0.000 description 1
- MXRIRQGCELJRSN-UHFFFAOYSA-N O.O.O.[Al] Chemical compound O.O.O.[Al] MXRIRQGCELJRSN-UHFFFAOYSA-N 0.000 description 1
- 239000002202 Polyethylene glycol Substances 0.000 description 1
- FVFJGQJXAWCHIE-UHFFFAOYSA-N [4-(bromomethyl)phenyl]methanamine Chemical compound NCC1=CC=C(CBr)C=C1 FVFJGQJXAWCHIE-UHFFFAOYSA-N 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 229910021529 ammonia Inorganic materials 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 239000001768 carboxy methyl cellulose Substances 0.000 description 1
- 235000010948 carboxy methyl cellulose Nutrition 0.000 description 1
- 239000008112 carboxymethyl-cellulose Substances 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000003344 environmental pollutant Substances 0.000 description 1
- 239000002360 explosive Substances 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000010815 organic waste Substances 0.000 description 1
- 230000000704 physical effect Effects 0.000 description 1
- 231100000719 pollutant Toxicity 0.000 description 1
- 229920001223 polyethylene glycol Polymers 0.000 description 1
- 229920000193 polymethacrylate Polymers 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 230000001131 transforming effect Effects 0.000 description 1
- 229920003169 water-soluble polymer Polymers 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/30—Preparation of aluminium oxide or hydroxide by thermal decomposition or by hydrolysis or oxidation of aluminium compounds
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01F—COMPOUNDS OF THE METALS BERYLLIUM, MAGNESIUM, ALUMINIUM, CALCIUM, STRONTIUM, BARIUM, RADIUM, THORIUM, OR OF THE RARE-EARTH METALS
- C01F7/00—Compounds of aluminium
- C01F7/02—Aluminium oxide; Aluminium hydroxide; Aluminates
- C01F7/021—After-treatment of oxides or hydroxides
-
- C—CHEMISTRY; METALLURGY
- C01—INORGANIC CHEMISTRY
- C01P—INDEXING SCHEME RELATING TO STRUCTURAL AND PHYSICAL ASPECTS OF SOLID INORGANIC COMPOUNDS
- C01P2004/00—Particle morphology
- C01P2004/30—Particle morphology extending in three dimensions
- C01P2004/32—Spheres
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Inorganic Chemistry (AREA)
- Physics & Mathematics (AREA)
- Thermal Sciences (AREA)
- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The invention discloses a preparation method of high wear-resistant microspherical alumina, which comprises the following steps: (1) preparation of an aluminum sol: aluminum powder and hydrochloric acid are used for synthesizing aluminum sol, wherein the average particle size of the aluminum powder is 55-75μm is preferably 55 to 65μm; (2) preparing a pseudo-boehmite filter cake: synthesizing to obtain a pseudo-boehmite filter cake by using aluminum salt and aluminate; (3) pseudo-boehmite surface modification: adding the pseudo-boehmite filter cake obtained in the step (2) into the alumina sol obtained in the step (1), stirring and dispersing, adding an alkaline solution, heating and aging, dehydrating the slurry, washing until the filtrate is neutral to obtain a filter cake, and drying the filter cake to obtain the surface-modified pseudo-boehmite; (4) preparing high wear-resistant microspherical alumina: adding deionized water into the surface modified pseudo-boehmite obtained in the step (3) for pulping, adding inorganic acid for peptizing, spray forming and roasting to obtain the high-wear-resistance microspherical alumina. The invention modifies the surface of pseudo-boehmite to obtain the high wear-resistant productMicrospherical alumina.
Description
Technical Field
The invention relates to a preparation method of microsphere alumina with high wear resistance, belonging to the field of chemical material synthesis.
Background
Alumina is often used as a support for preparing catalysts due to its porous structure and high mechanical strength. Common alumina carriers include strip-shaped, clover-shaped, spherical with the particle size of a few millimeters and microsphere with the particle size of tens to hundreds of micrometers, and the catalyst prepared by using the microsphere alumina can be used for a fluidized bed reactor, and the fluidized bed reactor has small volume, high yield and less byproducts due to large contact area and small mass transfer resistance. Because the microspherical catalyst is in a continuous motion state in the reactor, severe collision and friction exist among particles and between the particles and the inner wall of the reactor, the wear resistance directly determines the use condition of the catalyst in a fluidized bed, and the wear resistance of the carrier directly determines the wear resistance of the catalyst, so that the preparation of the microspherical alumina carrier with high wear resistance has important practical value.
CN1097351a discloses that pseudo-boehmite is pulped by adding water, then acid peptized, then pseudo-boehmite pulped, then alumina sol pulped, finally spray formed and baked to prepare microsphereγ-Al 2 O 3 The method comprises the steps of 30-55% of alumina in pseudo-boehmite, 21.5-23.5% of alumina in alumina sol, and obtaining microspheresγ-Al 2 O 3 The abrasion resistance is still to be further improved by 0.9% -2.5% of abrasion index per hour.
CN106475023a is first prepared into alumina sol by adding acid into amorphous alumina, then added with hexamethylenetetramine, surfactant and liquid paraffin, and finally spray-formed and baked after being fully homogenized and emulsified to prepare alumina microspheres. However, the surfactant and the liquid paraffin release a large amount of organic waste gas in the roasting process, which has adverse effects on the environment.
CN111468048A is prepared from low-sodium high-viscosity pseudo-boehmite by pulping with deionized water, grinding with equipment, adding additives such as ammonium polymethacrylate, polyethylene glycol, ammonium oleate and emulsified oil, spray forming, and roasting to obtain the alumina microsphere with abrasion index of 0.8% -1.3%. The grinding step has larger influence on the product performance, and the product performance fluctuation is easy to be caused. Furthermore, the direct use of filter cakes presents two problems: (1) The water content of the filter cake is higher, and then water is added to pulp to cause lower solid content in the slurry, so that the acid consumption is increased during peptization, and the pollutant generation amount is increased during the roasting process; (2) The filter cake is still slowly aged while it is in place, thus leading to fluctuations in product properties.
CN115920904a improves the abrasion resistance of a microspherical alumina carrier by adding a water-soluble polymer such as carboxymethyl cellulose, absolute ethyl alcohol and propylene oxide to a pseudo-boehmite slurry. However, the anhydrous ethanol and the propylene oxide used in the method are highly inflammable and explosive dangerous chemicals, and the safety risk of the spray forming process is high.
Disclosure of Invention
The invention aims to provide a preparation method of high-wear-resistance microspherical alumina, which has high wear resistance and wear index less than or equal to 0.5%.
In order to achieve the above purpose, the technical scheme of the invention is as follows: the preparation method of the high wear-resistant microspherical alumina comprises the following steps:
(1) Preparing aluminum sol: aluminum powder and hydrochloric acid are used for synthesizing aluminum sol, wherein the average particle size of the aluminum powder is 55-75μm is preferably 55 to 65μm；
(2) Preparing a pseudo-boehmite filter cake: synthesizing to obtain a pseudo-boehmite filter cake by using aluminum salt and aluminate;
(3) Surface modification of pseudo-boehmite: adding the pseudo-boehmite filter cake obtained in the step (2) into the alumina sol obtained in the step (1), stirring and dispersing, adding an alkaline solution, heating and aging, dehydrating the slurry, washing until the filtrate is neutral to obtain a filter cake, and drying the filter cake to obtain the surface-modified pseudo-boehmite;
(4) Preparing high wear-resistant microspherical alumina: adding deionized water into the surface modified pseudo-boehmite obtained in the step (3) for pulping, adding inorganic acid for peptizing, spray forming and roasting to obtain the high-wear-resistance microspherical alumina.
Preferably, in the step (1), the preparation method of the aluminum sol comprises the following steps: and (3) adding aluminum powder into deionized water under stirring, dropwise adding a hydrochloric acid aqueous solution, and keeping the temperature at 90-99 ℃ after the dropwise adding is finished for 2-4 h to obtain aluminum sol. The purity of the aluminum powder is generally greater than 99.9%, the mass fraction of the hydrochloric acid aqueous solution is generally 15% -25%, the mass fraction of the aluminum in the aluminum sol is generally 8% -15%, and the viscosity of the aluminum sol is generally 5% -50 mPa.s.
Preferably, in the step (2), deionized water is added into a reaction kettle, an aluminum salt aqueous solution and an aluminum salt aqueous solution are dropwise added in parallel under stirring, and stirring is continued after the dropwise addition is finished, and the temperature is kept at 50-80 DEG C1-2 h, followed by dewatering the slurry and washing the filter cake to neutrality. Wherein the aluminum salt can be aluminum chloride, aluminum nitrate, or aluminum sulfate, and the purity should be analytically pure, with Al 2 O 3 The aluminum salt aqueous solution with the calculated content is 70-90 g/L; the aluminates being generally sodium metaaluminate, with Al 2 O 3 The content of the calculated sodium metaaluminate aqueous solution is 120-200 g/L; the pH value is generally controlled to be 8.5-9.5 in the dripping process; the equipment used for dehydrating the slurry can be a plate-and-frame filter press, a centrifuge, a belt vacuum filter and the like.
Preferably, in the step (3), the ratio of the mass of aluminum in the aluminum sol to the mass of aluminum in the pseudo-boehmite filter cake is 1:3-1:5, the alkaline solution is generally an aqueous solution of hexamethylenetetramine and/or urea, the mass fraction of the alkaline solution is 20% -40%, and the ratio of the amount of N element in the alkaline solution to the amount of Cl element in the aluminum sol is 1.0-1.2:1; the temperature rise and aging conditions are as follows: and (3) heating to 120-150 ℃ at 0.30-0.60 MPa, and aging for 4-24 h.
Preferably, in the step (4), the inorganic acid is generally an aqueous solution of nitric acid, the mass fraction of nitric acid is generally 15% -25%, and the addition amount of nitric acid enables the viscosity of the slurry to be controlled to be 100-500 mPa.s; spray forming the inlet temperature of 150-250 ℃ and the outlet temperature of 100-120 ℃; the roasting temperature is preferably 800-1000 ℃.
The invention has the following beneficial effects:
(1) According to the invention, aluminum sol and alkaline solution are adopted to modify pseudo-boehmite, and the alkaline solution is decomposed to generate ammonia after the temperature is increased, so that the aluminum sol is slowly changed from acidity to alkalinity, and the aluminum sol is gradually changed into the high-cohesiveness pseudo-boehmite under a controlled condition;
(2) The surface of the surface modified pseudo-boehmite prepared by the invention is high-cohesiveness pseudo-boehmite prepared by the specific method by transforming alumina sol in alkaline environment, the structure reacts with inorganic acid in the subsequent peptization process to play a role of a binder, the wear resistance of the formed microspherical alumina is greatly improved, and the wear index is less than or equal to 0.5 percent.
Detailed Description
The invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
Example 1
(1) Preparing aluminum sol: adding 3.22. 3.22 kg deionized water into a reaction kettle, and adding high-purity aluminum powder (average particle diameter 63.0) under stirringμm) 0.37 to kg, adding 3.26 to kg of hydrochloric acid aqueous solution with the mass fraction of 20 percent, and continuously stirring and preserving heat at the temperature of 90 to 95 ℃ for 2 h after the dripping is finished to obtain aluminum sol, wherein the mass fraction of Al is 10.3 percent;
(2) Preparing a pseudo-boehmite filter cake: weighing analytically pure aluminum sulfate 3.94 and kg to prepare an aluminum sulfate aqueous solution, wherein Al 2 O 3 The content is 80 g/L. Weighing sodium metaaluminate solid 4.20 and kg to prepare sodium metaaluminate solution, wherein Al 2 O 3 The content is 200 g/L. Deionized water 9.00 kg is added into the reaction kettle, aluminum sulfate solution and sodium metaaluminate solution are added dropwise under stirring, the pH value is controlled to 9.0, and after the dropwise addition is finished, the mixture is continuously stirred and aged at 60 ℃ for 1 h. Transferring the slurry to a centrifuge after ageing, and washing with deionized water after liquid removal until filtrate becomes neutral to obtain a pseudo-boehmite filter cake;
(3) Surface modification of pseudo-boehmite: and (3) redispersing the pseudo-boehmite filter cake prepared in the step (2) in the alumina sol prepared in the step (1) at room temperature, adding 30% hexamethylenetetramine aqueous solution 1.03 and kg, pressurizing to 0.40 MPa, heating to 130 ℃, aging for 24 h, centrifuging again to remove liquid, and washing with deionized water until the filtrate is neutral to obtain the filter cake. And (3) flash drying the filter cake to obtain the surface modified pseudo-boehmite. The ratio of the mass of aluminum in the aluminum sol to the mass of aluminum in the filter cake is 1:3;
(4) Preparing high wear-resistant microspherical alumina: adding 9.33 kg deionized water into the surface modified pseudo-boehmite obtained in the step (3) again for pulping, adding 1.56 kg mass percent of 20% nitric acid aqueous solution again to the slurry viscosity of 200 mPa.s, controlling the air inlet temperature to 200-210 ℃ and the air outlet temperature to 110-120 ℃ during spray forming, and roasting the formed intermediate product at 900 ℃ for 4 hours to obtain the high wear-resistant microspherical alumina.
Example 2
Using an average particle size of 55μm high purity aluminum powder, other conditions are the same as those of the solidExample 1.
Example 3
Using an average particle size of 75μm high purity aluminum powder, otherwise the conditions are the same as in example 1.
Example 4
Adding 2.11. 2.11 kg deionized water into a reaction kettle, stirring, and adding high-purity aluminum powder (average particle diameter 60.0μm) 0.28 to kg, adding 1.95 to kg of hydrochloric acid aqueous solution with the mass fraction of 20 percent, and continuously stirring and preserving heat at the temperature of 90 to 95 ℃ for 2 h after the dripping is finished to obtain the aluminum sol, wherein the mass fraction of Al is 9.5 percent. A40% aqueous urea solution, 0.96, kg, was added with a 1:5 ratio of the mass of aluminum in the aluminum sol to the mass of aluminum in the filter cake. Otherwise, the same as in example 1 was conducted.
Example 5
The average grain diameter of the high-purity aluminum powder in the step (1) is 65.0μm, in step (3), the aging temperature was 145℃and the aging time was 6 hours, otherwise as in example 1.
Comparative example 1
Weighing analytically pure aluminum sulfate 3.94 and kg to prepare an aluminum sulfate aqueous solution, wherein Al 2 O 3 The content is 80 g/L. Weighing sodium metaaluminate solid 4.20 and kg to prepare sodium metaaluminate solution, wherein Al 2 O 3 The content is 200 g/L. Deionized water 3.22 and kg are added into a reaction kettle, an aluminum sulfate solution and a sodium metaaluminate solution are added dropwise under stirring, the pH value is controlled to be 9.0, and the mixture is continuously stirred after the dropwise addition is finished and aged at 60 ℃ for 1 h. Transferring the slurry to a centrifuge after ageing, and washing with deionized water after liquid removal until filtrate becomes neutral to obtain a pseudo-boehmite filter cake; and flash drying the filter cake to obtain pseudo-boehmite. Adding 7.00 kg deionized water again to pulp, adding 1.17 kg mass percent of 20% nitric acid aqueous solution again to the slurry viscosity of 200 mPa.s, controlling the air inlet temperature to be 200-210 ℃ and the air outlet temperature to be 110-120 ℃ when spray forming, and roasting the formed intermediate product at 900 ℃ for 4 hours to obtain the high wear-resistant microspherical alumina.
Comparative example 2
Step (3) "added to 30% aqueous hexamethylenetetramine solution 1.03. 1.03 kg" in example 1 was removed, and the procedure of example 1 was followed.
Comparative example 3
Using an average particle size of 100μm high purity aluminum powder, otherwise the conditions are the same as in example 1.
Comparative example 4
Using a mean particle diameter of 40μm high-purity aluminum powder, an aluminum sol with a sol viscosity of more than 1000 mpa·s was prepared under the conditions of example 4, and the sol became gel after standing, and the subsequent modification operation was not performed.
The abrasion index was determined using the YS/T438.2-2013 method for determining physical properties of sandy alumina part 2: determination of wear index the determination is carried out according to the method of "determination of wear index". The abrasion index was calculated as the mass percent of the fine powder collected over one hour of the blowing treatment to the total packed sample. The abrasion index reflects the generation rate of the sample fine powder after abrasion test, and the larger the value is, the poorer the abrasion resistance of the sample is, and the smaller the abrasion index is, the better the abrasion resistance of the sample is. The wear indexes of examples 1 to 5 and comparative examples 1 to 3 are shown in Table 1.
TABLE 1 wear index of microspherical alumina
| Wear index | |
| Example 1 | 0.2% |
| Example 2 | 0.1% |
| Example 3 | 0.5% |
| Example 4 | 0.4% |
| Example 5 | 0.4% |
| Comparative example 1 | 7.3% |
| Comparative example 2 | 6.7% |
| Comparative example 3 | 2.4% |
Claims (10)
1. The preparation method of the high wear-resistant microspherical alumina comprises the following steps:
(1) Preparing aluminum sol: aluminum powder and hydrochloric acid are used for synthesizing aluminum sol, wherein the average particle size of the aluminum powder is 55-75μm is preferably 55 to 65μm；
(2) Preparing a pseudo-boehmite filter cake: synthesizing to obtain a pseudo-boehmite filter cake by using aluminum salt and aluminate;
(3) Surface modification of pseudo-boehmite: adding the pseudo-boehmite filter cake obtained in the step (2) into the alumina sol obtained in the step (1), stirring and dispersing, adding an alkaline solution, heating and aging, dehydrating the slurry, washing until the filtrate is neutral to obtain a filter cake, and drying the filter cake to obtain the surface-modified pseudo-boehmite;
(4) Preparing high wear-resistant microspherical alumina: adding deionized water into the surface modified pseudo-boehmite obtained in the step (3) for pulping, adding inorganic acid for peptizing, spray forming and roasting to obtain the high-wear-resistance microspherical alumina.
2. The method according to claim 1, wherein in the step (1), the method for preparing the alumina sol comprises: and (3) adding aluminum powder into deionized water under stirring, dropwise adding a hydrochloric acid aqueous solution, and keeping the temperature at 90-99 ℃ after the dropwise adding is finished for 2-4 h to obtain aluminum sol.
3. The preparation method according to claim 1 or 2, wherein in the step (1), the mass fraction of aluminum in the aluminum sol is 8% -15%.
4. The preparation method according to claim 1, wherein in the step (2), deionized water is added into the reaction kettle, an aluminum salt aqueous solution and an aluminum salt aqueous solution are added dropwise under stirring, stirring is continued after the completion of the dropwise addition, heat is preserved at 50-80 ℃ for 1-2 h, and then the slurry is dehydrated and the filter cake is washed to be neutral.
5. The method according to claim 4, wherein in the step (2), the aluminum salt is selected from aluminum chloride, aluminum nitrate and aluminum sulfate, and the aluminate is sodium metaaluminate.
6. The method according to claim 1, wherein in the step (3), the alkaline solution is an aqueous solution of hexamethylenetetramine and/or urea, and preferably the ratio of the amount of the substance of N element in the alkaline solution to the amount of the substance of Cl element in the alumina sol is 1.0 to 1.2:1.
7. The method according to claim 1, wherein in the step (3), the ratio of the mass of aluminum in the alumina sol to the mass of aluminum in the pseudo-boehmite filter cake is 1:3 to 1:5.
8. The method according to claim 1, wherein in the step (3), the temperature-raising aging condition is: and (3) heating to 120-150 ℃ at 0.30-0.60 MPa, and aging for 4-24 h.
9. The preparation method according to claim 1, wherein in the step (4), the inorganic acid is an aqueous solution of nitric acid, and the mass fraction of nitric acid is 15% -25%.
10. The method according to claim 1, wherein in the step (4), the spray forming inlet temperature is 150 to 250 ℃ and the outlet temperature is 100 to 120 ℃; the roasting temperature is 800-1000 ℃.
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| Application Number | Priority Date | Filing Date | Title |
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| CN202311158596.3A CN117285060A (en) | 2023-09-08 | 2023-09-08 | Preparation method of high-wear-resistance microspherical alumina |
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| Application Number | Priority Date | Filing Date | Title |
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