Process for preparing active alumina

A technology of activated alumina and sodium metaaluminate, which is applied in the preparation of alkali metal aluminate/alumina/aluminum hydroxide, can solve the problems of low production efficiency, long neutralization reaction time, increased energy consumption, etc., and achieve Save the cooling equipment, shorten the gelation time, and reduce the production cost

Inactive Publication Date: 2003-05-28
XIAMEN UNIV
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the CO in the mixture 2 Low content, long neutralization reaction time, easy to generate gibbsite, so that the porosity of the final product is low, and the pore volume of the prepared activated alumina product is less than 0.75ml g -1
CN1254684A patent application is to solve the problem of product porosity low, use low temperature (15~25 ℃) and low sodium metaaluminate solution (20~35g Al 2 o 3 ·L -1 ), but still use low concentration CO 2 Mixed gas with air, the side effects of this method are: 1) During summer production, cooling equipment must be used to increase energy consumption; 2) Production efficiency is low

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0013] Take industrial first grade aluminum hydroxide powder [containing Al 2 O 3 63%(w)]150g and 40%(w)NaOH aqueous solution 148g, add 230g deionized water and heat to 100℃ with stirring, keep constant temperature for 120min, until the aluminum hydroxide is completely dissolved to obtain a concentration of 270g Al 2 O 3 ·L -1 Sodium metaaluminate solution (NaOH / Al(OH) 3 The mol ratio is 1.3), and then diluted with deionized water to a concentration of 25g·Al 2 O 3 ·L -1 Of sodium metaaluminate solution, the gel forming temperature is controlled to 60℃, and CO-containing 2 98%(V) of CO 2 -Air mix the gas and add a stirrer for stirring. When the pH value drops to 10.2 (18min), stop the gas and stirring. The slurry is subjected to conventional solid-liquid separation, and the filter cake is washed with 60℃ deionized water until it is neutral. Dry for 8h at ℃, and calcinate at 550℃ for 3h to obtain γ-Al 2 O 3 , Its main properties are listed in Table 1.

Embodiment 2

[0015] The preparation method is the same as in Example 1. The concentration of the concentrated sodium metaaluminate solution is diluted to 50g Al 2 O 3 ·L -1 , The results obtained are listed in Table 1.

[0016] Reference example 1~2

[0017] In Example 1, the concentration of the concentrated sodium metaaluminate solution was diluted to 75g Al 2 O 3 ·L -1 And 85g Al 2 O 3 ·L -1 , The main properties of the products obtained are listed in Table 1.

[0018]

Embodiment 3～5

[0020] Change the gel forming temperature to 30°C, 45°C, 70°C, and the rest are the same as in Example 1. The main properties of the product are shown in Table 2.

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Abstract

A process for preparing the active aluminium oxide includes preparing the solution of sodium metaaluminate from powdered aluminium hydroxide and sodium hydroxide, introducing high-concentration CO2 gas mixture, colloidizing at 20-70 deg.C, regulating pH=9-11, filtering, washing the filtered cake, drying at 60-100 deg.C to obtain alpha-AlO(OH), and calcining at 500-700 deg.C. Its advantages are high reaction speed, low CO2 consumption and low cost.

Description

(1) Technical field [0001] The invention relates to a preparation method of activated alumina. (2) Background technology [0002] Activated alumina refers to γ-Al 2 O 3 , Η-Al 2 O 3 And its mixtures. Because activated alumina has developed pores and good thermal stability, it is widely used in catalyst carriers, desiccants and adsorbents. When preparing activated alumina, the precursor, pseudo-boehmite, is generally prepared first, and then roasted at a high temperature to transform its crystal phase. Among the various methods for preparing pseudo-boehmite, the sodium metaaluminate and carbon dioxide neutralization method has the lowest cost, and many patents have been applied for this method at home and abroad. Among them, the production process disclosed in the CN1057443A patent application mainly includes raw material preparation, gel forming, aging, washing, solid-liquid separation and drying. In the process of gel forming, the acid gas introduced into sodium metaaluminate co...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/14
Inventor 方维平盛景云王跃敏
Owner XIAMEN UNIV
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