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Preparation of alumina

A technology of aluminum oxide and aluminum hydroxide, applied in the direction of aluminum oxide/aluminum hydroxide, etc., can solve the problem of no hole expansion, etc., and achieve the effects of short contact time, increased pore size, and increased pore volume

Inactive Publication Date: 2002-09-25
CHINA PETROCHEMICAL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

From the perspective of product performance, although the pore distribution of the alumina modified by this method has been improved, it has no pore expansion effect.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0023] Alumina is prepared according to the method provided by the invention.

[0024] (1) will be Al 2 o 3 Put 15 liters of sodium metaaluminate solution with a metered content of 80 g / L and a caustic coefficient of 1.6 into a 20-liter tank, and inject a mixture of carbon dioxide and air from the bottom of the tank for neutralization reaction. The flow rate is 8 meters 3 / hour, the concentration of carbon dioxide in the mixed gas is 35% by volume, the reaction temperature is maintained at 20-25 ° C, until the pH value of the slurry is 10, stop feeding the mixed gas, filter, and wash the precipitate 4 times with room temperature deionized water, each time with 5000 milliliters of deionized water, obtain aluminum hydroxide wet filter cake. Al in wet filter cake 2 o 3 20% by weight (measured by weight method), a small amount of aluminum hydroxide wet filter cake is dried, and its crystal phase is measured by X-ray diffraction method, which proves that all the aluminum hyd...

example 2

[0027] Alumina is prepared according to the method provided by the invention.

[0028] Prepare alumina according to the method described in (2) in Example 1, the difference is that the temperature at which carbon dioxide, ammoniacal liquor contact the aluminum hydroxide slurry is maintained at 45 ± 5 ° C, after the aluminum hydroxide slurry is added, no further carbon dioxide and carbon dioxide are added. Ammonia, no standing step, other conditions unchanged, get alumina product A 2 . A 2 The specific surface area, pore volume and pore distribution are listed in Table 1.

example 3

[0030] Alumina is prepared according to the method provided by the invention.

[0031] Alumina is prepared according to the method described in (2) in Example 1, except that the carbon dioxide gas is changed into a mixture of carbon dioxide and air containing 35 vol% of carbon dioxide, and the flow rate of the mixture is 1.8 m 3 / hour, other conditions remain unchanged, get alumina product A 3 . A 3 The specific surface area, pore volume and pore distribution are listed in Table 1.

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PUM

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Abstract

The preparation of alumina includes contacting ammonium ion containing water solution of carbonate radical ion or hydrocarbonate radical ion with a slurry of aluminum hydroxide and water for at least30 min at 10-300 deg.C, filtering, and calcining obtained filter cake at 500-700 deg.c. The molar ratio of ammonium ion to aluminum hydroxide is not lower than 0.5 by NH3 and Al2O3, and the molar ratio of carbonate radical ion and / or hydrocarbonate radical ion is not lower than 1 by CO2 and Al2O3. Utilizing the method can increase the pore volume and pore diameter simultaneously, and the alumina thus prepared is especially suitable for use as carrier for the hydrogenating demetalization catalyst.

Description

field of invention [0001] The invention relates to a method for preparing alumina. Background technique [0002] US 4,001,144 discloses a method for modifying the pore distribution of an alumina-based catalyst carrier precursor, the method comprising (a) treating an alumina precursor of x-ρ-η structure with an aqueous ammonium salt solution selected from from the group consisting essentially of ammonium carbonate, ammonium bicarbonate and mixtures thereof; (b) subjecting alumina treated with said ammonium salt to pressure treatment at a temperature of about 100-160°C for 10-24 hours; (c) drying the pressure-treated alumina at about 100-200° C. for about 1-24 hours, and activating at about 500-700° C.; and (d) recovering modified pores without η phase Distributed alumina-based catalyst support characterized by a pore volume of at least 70% of the total volume of pores having a pore diameter of 45-300 angstroms. From the perspective of product perfo...

Claims

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Application Information

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IPC IPC(8): C01F7/02
Inventor 杨清河李大东庄福成石亚华康小洪
Owner CHINA PETROCHEMICAL CORP
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