Preparation method for aluminum oxide by direct forming method

A technology for forming alumina and aluminum hydroxide, which is applied in the direction of aluminum hydroxide preparation, alumina/hydroxide preparation, etc., and can solve problems such as little application value

Inactive Publication Date: 2013-02-13
CHINA NAT OFFSHORE OIL CORP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This method requires the assistance of carbonate ions in the neutralization preparation process, and the addition of calcined alumina powder, the minimum strength of the prepared alumina is only 0.5kgf / grain, and the practical application value is not great

Method used

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  • Preparation method for aluminum oxide by direct forming method

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Effect test

Embodiment 1

[0035] Under the condition of stirring, 3000 grams of sodium aluminate solution with a concentration of 150 grams of alumina per liter, and an aluminum sulfate solution with a concentration of 80 grams of alumina per liter were neutralized in parallel. In the sodium metaaluminate solution Add 4 grams of ammonium phosphate, and add sodium metaaluminate at a rate of 1.8 liters / hour into a 5-liter gelling tank, keep the gelling temperature at 40±2°C, adjust the flow rate of aluminum sulfate to keep the pH value at 8.5±0.3, To neutralize the initial slurry add 2 grams of sodium stearate. Aging for 60 minutes after the neutralization reaction, the aging temperature is 50°C, the aging pH is 8.5±0.3, and 120 grams of ammonium bicarbonate is added at the end of the aging. Wash 6 times with 15 liters of deionized water, and filter to obtain a wet filter cake. The filter cake was extruded into strips with a diameter of 4 mm, dried at 120°C, and calcined at 550°C for 4 hours to obtain a...

Embodiment 2

[0037] Alumina was prepared according to the method in Example 1, except that the neutralization temperature was 75° C., and the neutralization pH was 7.5 ± 0.3, and 5 grams of polyethylene glycol 4000 was mixed into the raw material sodium aluminate solution, and it was soaked with ammonia water at the end of aging. The pH was adjusted to 8.5±0.3, the aging temperature was 75°C, and the aging pH was 8.0±0.3 to obtain alumina A2. The physical and chemical properties of alumina A2 are shown in Table 1.

Embodiment 3

[0039] Alumina was prepared according to the method of Example 1, except that the neutralization temperature was 60°C, the neutralization pH was 8.8, 10 grams of sodium stearate was added to the slurry at the beginning of neutralization, and the aging temperature was 70°C to obtain alumina A3, the physical and chemical properties of alumina A3 are shown in Table 1.

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Abstract

The invention discloses a preparation method for aluminum oxide by a direct forming method. The method is characterized in that the aluminum oxide is directly formed by a wet filter cake, wherein pore volume is 0.3-0.8ml/g; a specific surface area is 150-300 m<2>/g; and crushing strength is 30-120 N/particle; the preparation process comprises the steps: a) meta-aluminate containing aluminum or a strong acid salt compound is neutralized with a precipitator solution at a temperature of 30-80 DEG C and pH of 6-9; accessory ingredient is added in a neutralizing process; mixture is aged for at least 10min after neutralizing; b) prepared aluminium hydroxide gel is washed by de-ionized water for 4-10 times; dosage of the de-ionized water for each time is 10-40 times of mass of a dried substrate of prepared aluminium hydroxide; a hydrated alumina filter cake is obtained after washing and filtering; content of the aluminium hydroxide in the filter cake is controlled to be 5-50%; and c) the accessory ingredient is added into one or various liquid in the step a) and step b); the filter cake after washing is formed by a normal forming method; and the formed filter cake is dried at a temperature of 80-120 DEG C and calcined at a temperature of 450-1000 DEG C to obtain a finished product of the aluminum oxide.

Description

technical field [0001] The invention relates to a method for preparing alumina, in particular to a method for preparing alumina that is directly molded by using filter cake obtained after alumina neutralization, precipitation, aging and water washing. Background technique [0002] Alumina has well-developed pores and good thermal stability. It is an inorganic oxide widely used in industry. It can be used in desiccants, adsorbents and catalyst supports, and can also be used alone as a catalyst. When alumina is used as a catalyst or its carrier, its properties play a very important role in the performance of the entire catalyst. It is generally required that the crystallinity of alumina should be high and the content of impurity ions should be low. The alumina formed after calcination should have a suitable specific surface area, high strength and moderate pore volume. [0003] In the preparation process of alumina, its precursor—pseudoboehmite is generally prepared first, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/30C01F7/34
Inventor 杨玉旺戴清于海斌刘敬利刘红光
Owner CHINA NAT OFFSHORE OIL CORP
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