Preparation method of high-gel-solubility aluminum oxide

Abstract

The present application relates to a kind of preparation methods of high peptizing alumina, belong to alumina synthesis technical field.This preparation method of high peptizing alumina is obtained by spray mixing reaction with the aqueous solution of additive of aluminum isopropoxide heated to melt, and powder solid, powder solid is dried, high temperature sintering obtains high peptizing alumina.The additive is selected from at least one of acetylene glycol polyether, decyne glycol polyether, diethylene glycol monobutyl ether, diphenyl ether.The present application is realized by adding additive, combining the method of spray hydrolysis to improve the peptizing index of alumina powder, and when changing raw material ratio and reaction temperature, the alumina powder obtained has relatively stable peptizing index.At the same time, the method can reduce the amount of water used in synthesis process, greatly reduce the reaction time, obtain stable high peptizing index alumina product, is an energy-saving, environment-friendly alumina preparation process.

Description

Technical Field

[0001] The invention relates to a method for synthesizing alumina, specifically a method for preparing highly colloidal alumina, belonging to the field of alumina preparation technology. Background Technology

[0002] Pseudoboehmite, also known as colloidal boehmite, can be used as a support or binder in hydrocracking and hydrorefining catalysts. Pseudoboehmite, when used as a binder, can increase the mechanical strength and pore structure of the catalyst to a certain extent, improve its catalytic performance, and provide suitable acidity. The quality of the pseudoboehmite's colloidal properties directly affects the catalyst's pore structure and crush resistance, thus influencing its selectivity, stability, and activity. The colloidal index is an important parameter for evaluating the colloidal properties of pseudoboehmite. Therefore, in recent years, companies have increasingly emphasized the evaluation of the colloidal index of alumina products.

[0003] Boehmite can be heat-treated at different temperatures to generate α-Al₂O₃, β-Al₂O₃, and γ-Al₂O₃ with rich porous structures. The alumina used in the preparation of catalytic cracking catalysts requires a colloidal index of 85%. However, current synthesis processes struggle to achieve a colloidal index of 85%, and the reproducibility of the colloidal index is poor, often fluctuating between 1 and 70 under the same process conditions. To obtain stable alumina sols, researchers have conducted extensive work investigating the factors affecting the colloidal solubility of boehmite, but an effective process for preparing stable colloidal alumina has yet to be found. Summary of the Invention

[0004] The purpose of this invention is to provide a method for preparing alumina with a high colloidal index. The colloidal index of alumina is increased by adding additives in conjunction with a spray hydrolysis method.

[0005] The technical solution adopted in this invention is a method for preparing highly colloidal alumina, comprising the following steps: heating aluminum isopropoxide to a molten state, mixing the molten aluminum isopropoxide with an aqueous solution of an additive via spray mixing to obtain a powdered solid, and drying the powdered solid to obtain the highly colloidal alumina.

[0006] The additive is selected from at least one of acetylenic diol polyether, diethylene glycol monobutyl ether, and biphenyl ether.

[0007] The mass ratio of the additive to aluminum isopropoxide is 0.005~0.1:1.

[0008] In some specific preparation methods, the auxiliary agent is selected from at least one of decynyl glycol polyether and diethylene glycol monobutyl ether.

[0009] The mass ratio of the additive to aluminum isopropoxide is 0.01~0.05:1.

[0010] In some specific preparation methods, the mass ratio of the additive to aluminum isopropoxide is 0.01~0.03:1.

[0011] In some specific preparation methods, the auxiliary agent is selected from at least one of decynyl diol polyethers.

[0012] In some specific preparation methods, the temperature for heating aluminum isopropoxide to the melt is 120~150 ℃, and the temperature for the spray mixing reaction is 70~120 ℃.

[0013] In some specific preparation methods, the temperature for heating aluminum isopropoxide to the melt is 125~140 ℃, and the temperature for spray mixing reaction is 80~100 ℃.

[0014] In some specific preparation methods, the drying temperature of the powdered solid is 80-120 ℃.

[0015] In some specific preparation methods, the drying temperature of the powdered solid is 90-100 ℃, and the drying time is 3-5 h.

[0016] The beneficial effects of this invention are: (1) The technical solution of the present invention improves the colloidal index of alumina powder by adding additives and combining spray hydrolysis. When the raw material ratio and reaction temperature are changed, the alumina powder obtained has a relatively stable colloidal index.

[0017] (2) The alumina powder prepared by the present invention has a high colloidal index and a high density, and the density value does not fluctuate much under different raw material ratios and different temperatures.

[0018] (3) The preparation method of the present invention reduces the amount of water used in the hydrolysis process by spraying, thereby reducing the amount of wastewater in the synthesis process, greatly reducing the reaction time, and obtaining a stable high colloidal index alumina product. It is an energy-saving and environmentally friendly alumina preparation process. Detailed Implementation

[0019] To further illustrate the invention, the following embodiments are provided, but they do not limit the scope of the invention as defined by the appended claims. Example 1

[0020] 5 g of acetylacetonate diol polyether FS-660 was dissolved in 300 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and heated to 125 °C to melt. The auxiliary agent solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the auxiliary agent droplets were contacted and hydrolyzed in a reaction vessel at 70 °C. The resulting powder was dried at 125 °C for 3 h to obtain alumina powder. Example 2

[0021] 20 g of acetylacetonate diol polyether FS-660 was dissolved in 500 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and heated to 130 °C to melt. The auxiliary agent solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets contacted the auxiliary agent droplets and hydrolyzed in a reaction vessel at 85 °C. The resulting powder was dried at 130 °C for 3 h to obtain alumina powder. Example 3

[0022] 30 g of acetylacetonate diol polyether FS-660 was dissolved in 500 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and heated to 130 °C to melt. The auxiliary agent solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the auxiliary agent droplets were contacted and hydrolyzed in a reaction vessel at 90 °C. The resulting powder was dried at 100 °C for 4 h to obtain alumina powder. Example 4

[0023] 40 g of acetylacetonate diol polyether FS-660 was dissolved in 800 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and heated to 135 °C to melt. The auxiliary agent solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the auxiliary agent droplets were hydrolyzed in a reaction vessel at 85 °C. The resulting powder was dried at 105 °C for 4 h to obtain alumina powder. Example 5

[0024] 50 g of acetylacetonate diol polyether FS-660 was dissolved in 1000 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and heated to 135 °C to melt. The auxiliary agent solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the auxiliary agent droplets were contacted and hydrolyzed in a reaction vessel at 100 °C. The resulting powder was dried at 100 °C for 5 h to obtain alumina powder. Example 6

[0025] 70 g of acetylacetonate diol polyether FS-620 was dissolved in 1000 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and heated to 135 °C to melt. The auxiliary agent solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the auxiliary agent droplets were hydrolyzed in a reaction vessel at 105 °C. The resulting powder was dried at 105 °C for 4 h to obtain alumina powder. Example

[0026] 100 g of acetylacetonate diol polyether FS-683 was dissolved in 1000 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and heated to 140 °C to melt. The auxiliary agent solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the auxiliary agent droplets were hydrolyzed in a reaction vessel at 110 °C. The resulting powder was dried at 110 °C for 3 h to obtain alumina powder. Example 7

[0027] 30 g of acetylacetonate diol polyether FS-640 was dissolved in 1500 g of deionized water to prepare an additive solution. 1000 g of aluminum isopropoxide was weighed and heated to 145 °C to melt. The additive solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the additive droplets were hydrolyzed in a reaction vessel at 90 °C. The resulting powder was dried at 85 °C for 5 h to obtain alumina powder. Example 8

[0028] 30 g of acetylacetonate diol polyether FS-660 was dissolved in 300 g of deionized water to prepare an additive solution. 1000 g of aluminum isopropoxide was weighed and heated to 135 °C to melt. The additive solution and the melted aluminum isopropoxide were sprayed out as atomized droplets through a spraying device. The nozzles of the two spraying devices were opposite each other. The aluminum isopropoxide droplets and the additive droplets were hydrolyzed in a reaction vessel at 90 °C. The resulting powder was dried at 120 °C for 4 h to obtain alumina powder. Example 9

[0029] The preparation process is the same as in Example 9, except that the powdered material is dried at 110 °C for 4 h to obtain alumina powder. Example 10

[0030] The preparation process is the same as in Example 9, except that the powdered material is dried at 90 °C for 5 h to obtain alumina powder.

[0031] Comparative Example 1 30 g of acetylacetonate diol polyether FS-660 was dissolved in 5000 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and added to the auxiliary agent solution. The mixture was heated to 90 °C for 5 h for hydrolysis. After filtration, the resulting solid was dried at 120 °C for 4 h to obtain alumina powder.

[0032] Comparative Example 2 20 g of acetylacetonate diol polyether FS-660 was dissolved in 4000 g of deionized water to prepare an auxiliary agent solution. 1000 g of aluminum isopropoxide was weighed and added to the auxiliary agent solution. The mixture was heated to 95 °C for 5 h for hydrolysis. After filtration, the resulting solid was dried at 100 °C for 6 h to obtain alumina powder. Example 11

[0033] The colloidal index, density, and purity of the samples prepared in Examples 1-9 and Comparative Examples 1-2 were determined as follows: Colloidal index: Prepare a 10% alumina suspension by mixing the sample (m1) with water. Add nitric acid at an acid-to-alumina ratio of n(acid):n(Al) = 1:10 and stir for 15 min. After colloidal dissolution, centrifuge at 5000 r / min for 10 min. Dry and cool the bottom precipitate and weigh it (m2). The fraction of alumina in the colloidal portion relative to the total alumina content in the sample [100% × (m1 - m2) / m1] is the colloidal index.

[0034] Density: Determined using the tapped density method.

[0035] Table 1 Performance indicators of alumina samples Example 2 90 0.71 Example 3 93 0.74 Example 4 91 0.65 Example 5 90 0.68 Example 9 96 0.73 Comparative Example 1 65 0.53 Comparative Example 2 60 0.50 As shown in Table 1, the alumina prepared in the examples has a higher colloidal index, and the colloidal index does not fluctuate much under different conditions. At the same time, the alumina prepared in this invention has a higher density.

[0036] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for preparing highly colloidal alumina, characterized in that, Includes the following steps: Aluminum isopropoxide is heated to a molten state, and the molten aluminum isopropoxide is mixed with an aqueous solution of an additive via spraying to obtain a powdered solid. The powdered solid is then dried to obtain the highly colloidal alumina. The auxiliary agent is selected from at least one of acetylenic diol polyether, diethylene glycol monobutyl ether, and biphenyl ether; The mass ratio of the additive to aluminum isopropoxide is 0.005~0.1:1; The temperature for the spray mixing reaction is 70~120℃.

2. The preparation method according to claim 1, characterized in that, The additive is selected from at least one of decynyl glycol polyether and diethylene glycol monobutyl ether; The mass ratio of the additive to aluminum isopropoxide is 0.01~0.05:

1.

3. The preparation method according to claim 2, characterized in that, The mass ratio of the additive to aluminum isopropoxide is 0.02 to 0.04:

1.

4. The preparation method according to claim 2, characterized in that, The additive is selected from at least one of decynyl diol polyether.

5. The preparation method according to any one of claims 1-4, characterized in that, The temperature at which aluminum isopropoxide is heated to melt is 120~150 ℃.

6. The preparation method according to claim 5, characterized in that, The temperature for heating aluminum isopropoxide to the point of melting is 125~140 ℃, and the temperature for spray mixing reaction is 80~100 ℃.

7. The preparation method according to any one of claims 1-4, characterized in that, The drying temperature for powdered solids is 80-120 ℃.

8. The preparation method according to claim 7, characterized in that, The drying temperature for powdered solids is 90-100 ℃, and the drying time is 3-5 h.

9. The preparation method according to any one of claims 1-4, characterized in that, The aqueous solution of the additive is heated to 50-90 °C and then mixed with molten aluminum isopropoxide by spraying to obtain a powdered solid.