Process for preparing active alumina

A technology of activated alumina and carbon dioxide, which is applied in the preparation of alkali metal aluminate/alumina/aluminum hydroxide, etc., can solve the problems of low production efficiency, long neutralization reaction time, increased energy consumption, etc., and save cooling Equipment, faster reaction rate, lower production cost

Inactive Publication Date: 2004-09-29
XIAMEN UNIV
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  • Summary
  • 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] Get industrial grade aluminum hydroxide powder [containing Al 2 o 3 63% (w)] 150g and 40% (w) NaOH aqueous solution 148g, add deionized water 230g and heat to 100°C under stirring, keep the temperature for 120min, until the aluminum hydroxide is completely dissolved to obtain a concentration of 270gAl 2 o 3 ·L -1 Sodium metaaluminate solution (NaOH / Al(OH) 3 mol ratio is 1.3), and then diluted with deionized water to a concentration of 25g Al 2 o 3 · L -1 Sodium metaaluminate solution, the temperature of gelation is controlled at 60°C, and CO 2 98% (V) CO 2 - Air mixed with gas and stirred with a stirrer, when the pH value dropped to 10.2 (18 minutes) stop feeding gas and stirring, the slurry was subjected to conventional solid-liquid separation, the filter cake was washed with deionized water at 60°C until neutral, 90°C ℃ drying for 8h, 550℃ calcination for 3h to get γ-Al 2 o 3 , and its main properties are listed in Table 1.

Embodiment 2

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

[0016] Refer to example 1~2

[0017] In Example 1, the concentration of 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 resulting product are listed in Table 1.

[0018]

Embodiment 3～5

[0020] Change the gelation temperature to 30°C, 45°C, and 70°C, and the rest are the same as in Example 1. The main properties of the product are shown in Table 2. Reference example 3: The gelling temperature is changed to 85°C, that is, the cost example, and the main properties of the obtained product are shown in Table 2.

[0021]

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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 mixtures thereof. Because activated alumina has well-developed pores and good thermal stability, it is widely used as catalyst carrier, desiccant and adsorbent, etc. When preparing activated alumina, its precursor, pseudo-boehmite, is generally prepared first, and then roasted at high temperature to transform its crystal phase. Among various methods for preparing pseudo-boehmite, the neutralization method of sodium metaaluminate and carbon dioxide has the lowest cost, and many patents have been declared for this method at home and abroad. Wherein the production process disclosed in the CN1057443A patent application, its main process is raw material preparation, gelling, aging, washing, solid-liquid separation and drying. During the gelation process of this process, the acid gas fed int...

Claims

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Application Information

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