CN115818681A - Method for preparing single crystal large-particle aluminum hydroxide by one-stage method - Google Patents
Method for preparing single crystal large-particle aluminum hydroxide by one-stage method Download PDFInfo
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- CN115818681A CN115818681A CN202211600785.7A CN202211600785A CN115818681A CN 115818681 A CN115818681 A CN 115818681A CN 202211600785 A CN202211600785 A CN 202211600785A CN 115818681 A CN115818681 A CN 115818681A
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- sodium aluminate
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- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 title claims abstract description 42
- 239000013078 crystal Substances 0.000 title claims abstract description 40
- 239000002245 particle Substances 0.000 title claims abstract description 30
- 238000000034 method Methods 0.000 title claims abstract description 23
- 238000000354 decomposition reaction Methods 0.000 claims abstract description 47
- 229910001388 sodium aluminate Inorganic materials 0.000 claims abstract description 43
- ANBBXQWFNXMHLD-UHFFFAOYSA-N aluminum;sodium;oxygen(2-) Chemical compound [O-2].[O-2].[Na+].[Al+3] ANBBXQWFNXMHLD-UHFFFAOYSA-N 0.000 claims abstract description 42
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims abstract description 40
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims abstract description 20
- 235000017557 sodium bicarbonate Nutrition 0.000 claims abstract description 20
- 239000002002 slurry Substances 0.000 claims abstract description 17
- 230000032683 aging Effects 0.000 claims abstract description 14
- 239000002270 dispersing agent Substances 0.000 claims abstract description 10
- 239000000243 solution Substances 0.000 claims description 48
- 229920001495 poly(sodium acrylate) polymer Polymers 0.000 claims description 5
- NNMHYFLPFNGQFZ-UHFFFAOYSA-M sodium polyacrylate Chemical compound [Na+].[O-]C(=O)C=C NNMHYFLPFNGQFZ-UHFFFAOYSA-M 0.000 claims description 5
- GVGUFUZHNYFZLC-UHFFFAOYSA-N dodecyl benzenesulfonate;sodium Chemical compound [Na].CCCCCCCCCCCCOS(=O)(=O)C1=CC=CC=C1 GVGUFUZHNYFZLC-UHFFFAOYSA-N 0.000 claims description 4
- 229940080264 sodium dodecylbenzenesulfonate Drugs 0.000 claims description 4
- 239000007864 aqueous solution Substances 0.000 claims description 3
- 235000010482 polyoxyethylene sorbitan monooleate Nutrition 0.000 claims description 3
- 229920000053 polysorbate 80 Polymers 0.000 claims description 3
- 239000012295 chemical reaction liquid Substances 0.000 claims description 2
- 238000001035 drying Methods 0.000 abstract description 8
- 238000005406 washing Methods 0.000 abstract description 8
- 238000009826 distribution Methods 0.000 abstract description 5
- 239000006185 dispersion Substances 0.000 abstract description 2
- 238000001816 cooling Methods 0.000 abstract 1
- 238000001914 filtration Methods 0.000 abstract 1
- 238000003756 stirring Methods 0.000 description 16
- 238000005303 weighing Methods 0.000 description 14
- 230000000052 comparative effect Effects 0.000 description 12
- 238000005054 agglomeration Methods 0.000 description 11
- 238000006243 chemical reaction Methods 0.000 description 11
- 230000002776 aggregation Effects 0.000 description 10
- 229910018072 Al 2 O 3 Inorganic materials 0.000 description 8
- 239000007787 solid Substances 0.000 description 8
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 229920002379 silicone rubber Polymers 0.000 description 6
- 210000000582 semen Anatomy 0.000 description 5
- 239000000203 mixture Substances 0.000 description 4
- 238000002360 preparation method Methods 0.000 description 4
- RNFJDJUURJAICM-UHFFFAOYSA-N 2,2,4,4,6,6-hexaphenoxy-1,3,5-triaza-2$l^{5},4$l^{5},6$l^{5}-triphosphacyclohexa-1,3,5-triene Chemical compound N=1P(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP(OC=2C=CC=CC=2)(OC=2C=CC=CC=2)=NP=1(OC=1C=CC=CC=1)OC1=CC=CC=C1 RNFJDJUURJAICM-UHFFFAOYSA-N 0.000 description 3
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 3
- 229910021502 aluminium hydroxide Inorganic materials 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 239000003063 flame retardant Substances 0.000 description 3
- 230000005484 gravity Effects 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000011734 sodium Substances 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 2
- 239000003518 caustics Substances 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000018109 developmental process Effects 0.000 description 2
- 238000000635 electron micrograph Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 239000004945 silicone rubber Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 1
- DBMJMQXJHONAFJ-UHFFFAOYSA-M Sodium laurylsulphate Chemical compound [Na+].CCCCCCCCCCCCOS([O-])(=O)=O DBMJMQXJHONAFJ-UHFFFAOYSA-M 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- VXAUWWUXCIMFIM-UHFFFAOYSA-M aluminum;oxygen(2-);hydroxide Chemical compound [OH-].[O-2].[Al+3] VXAUWWUXCIMFIM-UHFFFAOYSA-M 0.000 description 1
- SMYKVLBUSSNXMV-UHFFFAOYSA-K aluminum;trihydroxide;hydrate Chemical compound O.[OH-].[OH-].[OH-].[Al+3] SMYKVLBUSSNXMV-UHFFFAOYSA-K 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 238000003763 carbonization Methods 0.000 description 1
- 238000010891 electric arc Methods 0.000 description 1
- 238000001493 electron microscopy Methods 0.000 description 1
- 230000003628 erosive effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 238000011049 filling Methods 0.000 description 1
- 239000010419 fine particle Substances 0.000 description 1
- 230000002431 foraging effect Effects 0.000 description 1
- 230000017525 heat dissipation Effects 0.000 description 1
- 238000000265 homogenisation Methods 0.000 description 1
- 238000010335 hydrothermal treatment Methods 0.000 description 1
- 239000012796 inorganic flame retardant Substances 0.000 description 1
- 229910010272 inorganic material Inorganic materials 0.000 description 1
- 239000011147 inorganic material Substances 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 239000004973 liquid crystal related substance Substances 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000010899 nucleation Methods 0.000 description 1
- 229920000620 organic polymer Polymers 0.000 description 1
- 239000002861 polymer material Substances 0.000 description 1
- 239000000843 powder Substances 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000004575 stone Substances 0.000 description 1
- 230000001629 suppression Effects 0.000 description 1
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- Compounds Of Alkaline-Earth Elements, Aluminum Or Rare-Earth Metals (AREA)
Abstract
The method comprises the steps of reacting a sodium bicarbonate solution and a sodium aluminate solution through a super-gravity rotating bed, then aging, adding a dispersing agent, reacting and dispersing through the super-gravity rotating bed for the second time, then making seed crystals, and adding the sodium aluminate solution for natural cooling and one-stage decomposition; and filtering, washing, drying and depolymerizing the decomposed slurry to obtain a large single crystal aluminum hydroxide product with high dispersion and concentrated particle size distribution. The method has the advantages of simple process, high decomposition rate, low cost and industrial value.
Description
Technical Field
The invention relates to the field of inorganic material preparation, in particular to a production method of single crystal aluminum hydroxide.
Background
In the alumina production industry, the growth of aluminum hydroxide is mainly realized by controlling the process conditions through agglomeration and growth of fine-particle aluminum hydroxide. For example, CN200410037937, "decomposition method of high-strength large-particle aluminum hydroxide seed crystal", adopts self product circulation as seed crystal, and achieves the purpose of large-particle aluminum hydroxide by agglomeration and growth. However, the aluminum hydroxide is an agglomerate, and the performance requirements of aluminum hydroxide for special purposes cannot be met.
The supergravity rotating bed is used to produce nanometer or sub-nanometer level aluminum hydroxide, and for example, CN1258639A discloses a process for preparing superfine aluminum hydroxide, which consists of two steps of carbon decomposition and hydrothermal treatment under the supergravity condition of the rotating bed, wherein the obtained aluminum hydroxide particles are fibrous, the average particle size is 1-5 nm, and the length-diameter ratio is 5-100. CN200510032296 preparation method of superfine aluminium hydroxide contacts sodium aluminate NaAlO2 solution with gas containing carbon dioxide, carbonization reaction is carried out under the condition of supergravity to prepare aluminium hydroxide gel, then superfine aluminium hydroxide with different crystal forms is obtained, and granular aluminium hydroxide with the particle size of about 10nm is prepared and can be used as good inorganic flame retardant; the prepared nano fibrous pseudo-boehmite with the particle size of about 5nm and the length of 200-300 nm.
In the field of electrical and electronic technology, due to the rapid development of integration technology and assembly technology, electronic components and logic circuits have smaller and smaller volumes and higher power densities, which bring increasingly prominent heat dissipation problems, and insulating materials with high thermal conductivity are required. The aluminum hydroxide has the advantages of flame retardance, filling, smoke suppression and certain heat conduction performance. The large single crystal aluminum hydroxide with high crystallinity has good compatibility with organic polymer materials, good processing performance and better heat conduction and flame retardant performance after being compounded with other high heat conduction products.
In the formula of the silicon rubber, the aluminum hydroxide has great influence on the mechanical property, the electrical property, the hydrophobicity and the flame retardance of a product. The aluminum hydroxide filler can improve the performances of the silicon rubber such as tracking resistance, electric erosion resistance, electric arc resistance, flashover resistance and the like. When the granularity of the aluminum hydroxide is too small, the particles are difficult to uniformly disperse in a silicon rubber system, so that the mechanical property and the flame retardant property of the aluminum hydroxide are poor; when the particle size is too large, the specific surface area is small, the mechanical property is also low, and the compatibility of the aluminum hydroxide with the silicone rubber organic system is poor, so that the flame retardance of the aluminum hydroxide is poor. Only when the particle size is moderate, the mechanical property and the flame retardant property are better. Therefore, the development of the large single crystal aluminum hydroxide with the moderate particle size has positive practical significance.
Disclosure of Invention
The invention aims to provide a method for preparing single crystal large-grain aluminum hydroxide with high dispersion, moderate grain diameter and concentrated grain size distribution.
The method for preparing the single crystal large-grain aluminum hydroxide comprises the following steps:
1) The soda is prepared into an aqueous solution according to the mass ratio of 1.
2) Adding a dispersing agent, aging for 2-8h,
3) Then the reaction liquid is reacted and dispersed by a second super-gravity rotating bed,
4) And adding the obtained slurry into a sodium aluminate solution for decomposition for 60-120h to obtain the large single crystal aluminum hydroxide.
The invention adopts two times of high gravity field reaction and aging to prepare the seed crystal, and the seed crystal sodium aluminate solution can obtain the aluminum hydroxide large single crystal with the grain diameter of 1-10 microns, and the single crystal is very suitable for the application of silicon rubber and circuit board materials.
Detailed Description
N mentioned in the present disclosure k 、α k Have the ordinary meaning in the art. In particular, na of sodium aluminate solution 2 O content, including Na, which reacts with alumina to form sodium aluminate 2 O and free Na in the form of NaOH 2 O, they are all caustic and are noted N k The unit is g/l. Caustic Na in sodium aluminate solution 2 O and Al 2 O 3 The molar ratio of (A) is denoted as k 。
In the present disclosure, "highly dispersed" means that the product obtained by the process of the invention has a low degree of agglomeration, which is present essentially as a single crystal. Even if the agglomerates were present, they were not clearly present in the electron microscope. In the present disclosure, "moderate particle size" refers to a size suitable for use in silicone rubber and circuit board materials and maintaining good mechanical properties, and thermal conductivity, with the aluminum hydroxide crystal particle size being substantially between 1.0-10.0 μm. By "concentrated particle size distribution" is meant that the single crystal aluminum hydroxide obtained according to the inventive embodiment has a D50 of between 2.0 and 6.0, preferably a D50 value of between 3.0 and 5.5 μm, and a particle size Span value (calculated as (D90-D10)/D50) of typically between 1.0 and 2.0.
In the invention, in order to prepare proper seed crystals, two sections of high-gravity rotating bed reactions are adopted, and an aging process is carried out between the two sections. A large amount of nano-scale aluminum hydroxide crystal nuclei with uniform particle sizes are generated in a short time through the first stage of high gravity field reaction. Through the following aging process, the crystal nuclei grow up gradually in a spherical shape, and surface finishing is performed. Through the second hypergravity reaction, the agglomeration of crystal nuclei is eliminated to a great extent, and the further homogenization of the decomposition particle size is facilitated, and the obtained seed crystal is basically a single crystal. The seeds obtained by the process of the invention have low-agglomeration, low aspect ratio (not more than 3, in particular not more than 2) nanoscale seeds.
In a preferred embodiment, a dispersant is introduced in the aging stage, which may further reduce seed agglomeration. The dispersant used in the exemplary embodiment of the present invention is one or more of sodium polyacrylate, sodium dodecyl benzene sulfonate and tween 80, and the addition amount is 0.1 to 2g/L, preferably 0.2 to 1.5g/L, and more preferably 0.3 to 1g/L.
In a typical embodiment, a sodium aluminate solution Al is used 2 O 3 The content is 80g/L-180g/L, the ak value is 1.2-2.0, and Al in sodium aluminate solution is preferred 2 O 3 The content is 120g/L-150g/L, and ak is 1.3-1.5.
In the invention, baking soda is prepared into an aqueous solution according to the mass ratio of 1. Alternatively, the mass ratio of the sodium bicarbonate solid to the sodium aluminate solution can be controlled to be 1:8-20, preferably 1: 8-12. Within the range, the aging time of the prepared seed crystal is short, and the cost is favorably reduced.
In a preferred embodiment of the invention, the sodium bicarbonate solution enters the reactor at a temperature of 30-40 ℃, and the sodium aluminate solution enters the reactor at a temperature of 40-60 ℃, wherein the temperature is favorable for the crystal nucleus phase to be in the form of aluminum hydroxide of the Bayer stone, thereby creating conditions for reducing the agglomeration of the next decomposition.
In the step 2), the aging temperature is controlled to be 40-50 ℃. The aging time can be controlled to 2 to 8 hours, preferably 2 to 6 hours, and an excessively long time leads to an increase in the agglomeration of crystal nuclei. At this temperature and time, the agglomeration of crystal nuclei can be favorably prevented, and particularly, the above-mentioned amount of the dispersant is compounded.
In the step 4), the slurry containing the seed crystals obtained in the step 3) is added into a sodium aluminate solution according to the seed ratio of 0.01-0.05, and is decomposed for 60-120h at the temperature of 50-65 ℃. The preferable mode is that the initial decomposition temperature is 55-65 ℃, and the final decomposition temperature is not lower than 50 ℃.
Example 1:
(1) Weighing 1Kg of sodium bicarbonate solid, adding into 10Kg of warm water at 30 ℃, stirring to completely dissolve, weighing 10Kg of sodium aluminate solution, a k Is 1.5 of Al 2 O 3 The concentration is 152g/L, and the temperature is controlled at 50 ℃;
(2) The rotating speed of the super-gravity rotating bed is controlled at 1200rpm, the adding speed of the sodium bicarbonate solution and the semen is 60L/h, 0.5g/L sodium polyacrylate is added after the reaction, and the mixture is stirred and aged for 4h. The rotating speed of the rotating bed is still 1000rpm, and then the rotating bed passes through the rotating bed for the second time at the feeding speed of 60L/h;
(3) Adding the slurry passing through the secondary rotating bed in the step (2) into about 300L of sodium aluminate solution according to the seed ratio of 0.01 for decomposition, wherein the components of the sodium aluminate solution are the same as those in the step (1), the initial decomposition temperature is 65 ℃, the natural stirring decomposition is carried out for 65 hours, the final decomposition temperature is 60 ℃, and the decomposition rate reaches 45%;
(4) And (4) separating, washing, drying and dispersing the decomposed slurry in the step (3) to obtain the single crystal large-particle aluminum hydroxide, wherein an electron microscope is shown in a figure 1.
Example 2:
(5) Weighing 1Kg of sodium bicarbonate solid, adding into 6Kg of warm water at 40 ℃, stirring to dissolve it as much as possible, weighing 20Kg of sodium aluminate solution, a k Is 1.45 of Al 2 O 3 The concentration is 130g/L, and the temperature is controlled at 40 ℃;
(6) The rotating speed of the super-gravity rotating bed is controlled at 1000rpm, the adding speed of the sodium bicarbonate solution and the semen is 80L/h, 1g/L sodium dodecyl benzene sulfonate is added after the reaction, and the mixture is stirred and aged for 8h. The rotating speed of the rotating bed is still 1000rpm, and then the rotating bed passes through the rotating bed for the second time at the feeding speed of 80L/h;
(7) Adding the slurry passing through the secondary rotating bed in the step (6) into a sodium aluminate solution of about 380L according to the seed ratio of 0.02 for decomposition, wherein the components of the sodium aluminate solution are the same as those in the step (5), the initial decomposition temperature is 60 ℃, the natural stirring decomposition is carried out for 80 hours, the final decomposition temperature is 56 ℃, and the decomposition rate reaches 48%;
(8) And (3) separating, washing, drying and dispersing the decomposed slurry in the step (7) to obtain the single crystal large-particle aluminum hydroxide, wherein an electron microscope is shown in a figure 2.
Example 3:
(9) Weighing 1Kg of sodium bicarbonate solid, adding into 8Kg of warm water at 30 ℃, stirring to dissolve, weighing 8Kg of sodium aluminate solution, a k Is 1.6 of Al 2 O 3 The concentration is 150g/L, and the temperature is controlled at 60 ℃;
(10) The rotating speed of the hypergravity rotating bed is controlled at 1400rpm, the adding speed of the sodium bicarbonate solution and the semen is 100L/h, after the reaction, 1g/L of each of sodium polyacrylate (molecular weight 4000) and sodium dodecyl sulfate is added, and the mixture is stirred and aged for 6h. The rotating speed of the rotating bed is still 1000rpm, and then the rotating bed passes through the rotating bed for the second time at the feeding speed of 100L/h;
(11) Adding the slurry passing through the secondary rotating bed in the step (10) into about 50L of sodium aluminate solution according to the seed ratio of 0.05 for decomposition, wherein the components of the sodium aluminate solution are the same as those in the step (9), the initial decomposition temperature is 55 ℃, the natural stirring decomposition is carried out for 100 hours, the final decomposition temperature is 50 ℃, and the decomposition rate reaches 50%;
and (3) separating, washing, drying and dispersing the decomposed slurry in the step (11) to obtain the single crystal large-particle aluminum hydroxide, wherein an electron microscope is shown in figure 3.
Example 4:
(12) Weighing 1Kg of sodium bicarbonate solid, adding into 9Kg of warm water at 30 ℃, stirring to completely dissolve, weighing 9Kg of sodium aluminate solution, a k Is 1.5 of Al 2 O 3 The concentration is 160g/L, and the temperature is controlled at 62 ℃;
(13) The rotating speed of the super-gravity rotating bed is controlled at 1500rpm, the adding speed of the sodium bicarbonate solution and the semen is 60L/h, 1g/L of Tween 80 is added after reaction, and the mixture is stirred and aged for 5h. The rotating speed of the rotating bed is still 1000rpm, and then the rotating bed passes through the rotating bed for the second time at the feeding speed of 100L/h;
(14) Adding the slurry passing through the secondary rotating bed in the step (13) into about 50L of sodium aluminate solution according to the seed ratio of 0.05 for decomposition, wherein the components of the sodium aluminate solution are the same as those in the step (12), the initial decomposition temperature is 58 ℃, the natural stirring decomposition is carried out for 95 hours, the final decomposition temperature is 54 ℃, and the decomposition rate reaches 49%;
and (5) separating, washing, drying and dispersing the decomposed slurry in the step (14) to obtain the single-crystal large-grain aluminum hydroxide, wherein an electron microscope is shown in a figure 4.
Comparative example 1:
(1) Weighing 1Kg of sodium bicarbonate solid, adding into 10Kg of warm water at 30 ℃, stirring to completely dissolve, weighing 10Kg of sodium aluminate solution, a k Is 1.5 of Al 2 O 3 The concentration is 150g/L, and the temperature is controlled at 63 ℃;
(2) Adding the sodium bicarbonate solution in the step (1) into the sodium aluminate solution in the step (1), controlling the temperature to 63 ℃, and decomposing for 5 hours to obtain a liquid crystal;
(3) Adding the sodium aluminate solution with the seed ratio of 0.03 to about 100L for decomposition, wherein the components of the sodium aluminate solution are the same as those in the step (1), the initial decomposition temperature is 65 ℃, the decomposition is carried out for 70 hours by natural stirring, the final decomposition temperature is 56 ℃, and the decomposition rate reaches 46%;
(4) And (3) separating, washing, drying and dispersing the discharged slurry in the step (2) to obtain aluminum hydroxide crystals, wherein an electron micrograph is shown in figure 5.
Comparative example 2:
(1) Weighing 1Kg of sodium bicarbonate solid, adding into 10Kg of warm water at 30 ℃, stirring to completely dissolve, weighing 10Kg of sodium aluminate solution, a k Is 1.5 of Al 2 O 3 The concentration is 150g/L, and the temperature is controlled at 63 ℃;
(2) Adding the sodium bicarbonate solution in the step (1) into the sodium aluminate solution in the step (1) under the condition of stirring speed of 100rpm, wherein the adding speed is controlled at 80L/h. Then adding 1g/L sodium dodecyl benzene sulfonate and aging for 8h;
(3) Adding the sodium aluminate solution with the seed ratio of 0.03 into about 100L for decomposition, wherein the components of the sodium aluminate solution are the same as those in the step (1), the initial decomposition temperature is 65 ℃, the decomposition temperature is 60 ℃, and the decomposition rate reaches 47 percent, and naturally stirring and decomposing for 100 hours;
(4) And (4) separating, washing, drying and dispersing the decomposed slurry in the step (3) to obtain dry powder aluminum hydroxide, wherein an electron microscope is shown in figure 6.
Comparative example 3:
(1) Weighing 1Kg of sodium bicarbonate solid, adding into 10Kg of 30 ℃ warm water, stirring to completely dissolve, weighing 10Kg of sodium aluminate solution, a k Is 1.5 of Al 2 O 3 The concentration is 152g/L, and the temperature is controlled at 50 ℃;
(2) Controlling the rotating speed of the hypergravity rotating bed at 1200rpm, controlling the adding speed of the sodium bicarbonate solution and the semen at 60L/h, adding 0.5g/L sodium polyacrylate after reaction, stirring and aging for 4h;
(3) Adding the slurry passing through the primary rotating bed in the step (2) into about 300L of sodium aluminate solution according to the seed ratio of 0.01 for decomposition, wherein the components of the sodium aluminate solution are the same as those in the step (1), the initial decomposition temperature is 65 ℃, the natural stirring decomposition is carried out for 65 hours, the final decomposition temperature is 60 ℃, and the decomposition rate reaches 45%;
(4) And (4) separating, washing, drying and dispersing the decomposed slurry in the step (3) to obtain an aluminum hydroxide product, wherein an electron microscope is shown in a figure 7.
Comparative example 4
The experiment of example 1 was repeated except that no dispersant was added during the aging process and the results are shown in table 1 and in electron microscopy figure 8.
TABLE 1 index of examples
| Item | D50 | D10 | D90 | Span |
| Example 1 | 3.5 | 1.2 | 7.6 | 1.83 |
| Example 2 | 4.2 | 1.3 | 6.2 | 1.17 |
| Example 3 | 3.4 | 1.2 | 6.8 | 1.65 |
| Example 4 | 5.5 | 1.4 | 9.6 | 1.49 |
| Comparative example 1 | 5.0 | 1.0 | 16.2 | 3.04 |
| Comparative example 2 | 1.6 | 0.9 | 7.8 | 4.31 |
| Comparative example 3 | 3.6 | 1.1 | 9.8 | 2.42 |
| Comparative example 4 | 3.8 | 1.0 | 9.4 | 2.21 |
Referring to the electron micrographs in Table 1 and the accompanying drawings, in the above examples, examples 1 to 4, which employ the scheme of the present invention, the particle size of the product is substantially between 1 and 10 μm, and the Span value is less than 2. Comparative example 1 uses conventional seed crystals, the particle size of the product is larger, D10 is 5 μm, D90 is 16 μm, and the Span value is as high as 3.04, comparative example 2 does not use a high gravity field reactor to prepare the seed crystals, but the dispersing agent is added in the preparation process for aging, the particle size of the product is smaller, D50 is less than 2 μm, but the Span value is wider and reaches 4.31. Comparative example 3 differs from example 1 only in that the seeding process did not involve a second super-gravity rotating bed reaction and the resulting product showed some degree of agglomeration with a particle size D90 of 9.8 and a particle size distribution Span of 2.42. Comparative example 4 differs from example 1 only in that no dispersant was added during the aging process during the preparation of the seed crystal and the resulting product also showed some degree of agglomeration with a particle size D90 of 9.4 and a particle size distribution Span of 2.21.
The embodiments chosen for the purpose of this invention are to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims. It will be apparent to those skilled in the art that certain insubstantial modifications and adaptations of the present invention can be made without departing from the spirit and scope of the invention.
Claims (8)
1. The method for preparing the monocrystalline large-particle aluminum hydroxide by the one-step method comprises the following steps:
1) The baking soda is prepared into an aqueous solution according to the mass ratio of 1.
2) Adding a dispersant to age the slurry,
3) Then the reaction liquid is reacted and dispersed by a second super-gravity rotating bed,
4) And adding the obtained slurry into a sodium aluminate solution for decomposition for 60-120h to obtain the large single crystal aluminum hydroxide.
2. The process as claimed in claim 1, wherein the sodium aluminate solution Al used in steps 1) and 4) is a solution of sodium aluminate 2 O 3 Content of 80g/L to 180g/L, a k Value of 1.2-2.0, preferably Al in sodium aluminate solution 2 O 3 Content 120g/L-150g/L, a k Is 1.3-1.5.
3. The process according to claim 1, wherein the temperature of the aqueous baking soda solution of step 1) is between 30 ℃ and 40 ℃ and the temperature of the sodium aluminate solution is between 40 ℃ and 60 ℃.
4. The method of claim 1, wherein the aging temperature in step 2) is controlled at 40 ℃ to 50 ℃.
5. The method as claimed in claim 1, wherein the decomposition temperature of the sodium aluminate solution in step 4) is controlled to be 55-65 ℃.
6. The method of claim 1, wherein the dispersant is one or more of sodium polyacrylate, sodium dodecyl benzene sulfonate and tween 80, and the addition amount is 0.5-2g/L.
7. The method of claim 1, wherein the seed ratio added in step 4) is 0.01-0.05.
8. The method as claimed in claim 1, wherein the decomposition initial temperature in step 4) is 55 ℃ to 65 ℃, and the final temperature is not lower than 50 ℃ after natural decomposition for 60 to 120 hours.
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| CN202211600785.7A CN115818681B (en) | 2022-12-12 | 2022-12-12 | Method for preparing large-particle monocrystalline aluminum hydroxide by one-stage method |
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| CN202211600785.7A CN115818681B (en) | 2022-12-12 | 2022-12-12 | Method for preparing large-particle monocrystalline aluminum hydroxide by one-stage method |
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| CN115818681B CN115818681B (en) | 2024-01-23 |
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Citations (8)
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| WO2002094715A1 (en) * | 2001-05-18 | 2002-11-28 | Beijing University Of Chemical Technology | Ultrafine modified aluminium hydroxide and its preparation |
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| CN1752005A (en) * | 2005-10-25 | 2006-03-29 | 湘潭大学 | Preparation method of ultrafine active aluminium oxide |
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| JP2009242136A (en) * | 2008-03-28 | 2009-10-22 | Sumitomo Chemical Co Ltd | Production method of aluminum hydroxide |
| CN104045100A (en) * | 2014-06-27 | 2014-09-17 | 中国铝业股份有限公司 | Preparation method of aluminum hydroxide |
| CN109809453A (en) * | 2019-03-07 | 2019-05-28 | 洛阳中超新材料股份有限公司 | Ultrafine aluminium hydroxide and its preparation method and application |
| CN112875735A (en) * | 2021-02-09 | 2021-06-01 | 洛阳中超新材料股份有限公司 | Production method of high-crystallization-strength superfine aluminum hydroxide |
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| WO2002094715A1 (en) * | 2001-05-18 | 2002-11-28 | Beijing University Of Chemical Technology | Ultrafine modified aluminium hydroxide and its preparation |
| JP2005162606A (en) * | 2003-11-14 | 2005-06-23 | Showa Denko Kk | Manufacturing method of particulate aluminum hydroxide |
| CN1752005A (en) * | 2005-10-25 | 2006-03-29 | 湘潭大学 | Preparation method of ultrafine active aluminium oxide |
| CN1752006A (en) * | 2005-10-25 | 2006-03-29 | 湘潭大学 | Preparation method of ultrafine aluminium hydroxide |
| JP2009242136A (en) * | 2008-03-28 | 2009-10-22 | Sumitomo Chemical Co Ltd | Production method of aluminum hydroxide |
| CN104045100A (en) * | 2014-06-27 | 2014-09-17 | 中国铝业股份有限公司 | Preparation method of aluminum hydroxide |
| CN109809453A (en) * | 2019-03-07 | 2019-05-28 | 洛阳中超新材料股份有限公司 | Ultrafine aluminium hydroxide and its preparation method and application |
| CN112875735A (en) * | 2021-02-09 | 2021-06-01 | 洛阳中超新材料股份有限公司 | Production method of high-crystallization-strength superfine aluminum hydroxide |
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