Method for reducing sodium oxide in aluminum oxide by using carbon dioxide

A technology of carbon dioxide and medium sodium oxide, which is applied in the preparation of alumina/hydroxide, purification of aluminate/alumina/aluminum hydroxide, etc., can solve problems such as deformation and cracking of alumina products, and reduce product performance changes , reduce costs, and save the cost of high-temperature roasting

Active Publication Date: 2011-05-25
中铝山东有限公司
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  • Abstract
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the Na carried by the industrial aluminum hydroxide calcined products 2 The O content is 0.26-0.43% in total, and it is difficult to control the content of sodium oxide in the calcined product to Na 2 O2 o 3 The goal of ≥95% will lead to deformation and cracking of alumina products, and the use of sodium removal agents will produce certain side effects, such as boric acid and its compounds adhere to the surface of alumina in a liquid state, making them stick into blocks and block them. feed port

Method used

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  • Method for reducing sodium oxide in aluminum oxide by using carbon dioxide
  • Method for reducing sodium oxide in aluminum oxide by using carbon dioxide
  • Method for reducing sodium oxide in aluminum oxide by using carbon dioxide

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Experimental program
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Embodiment 1

[0018] Step 1. Pre-calcin industrial aluminum hydroxide at 600°C for 1 hour, then add the calcined product to distilled water to obtain an aqueous solution of the calcined product. The liquid-solid ratio of the distilled water to the alumina in the calcined product is L / S=10, that is 100g alumina, 1.0L distilled water, set aside;

[0019] Step 2. The aqueous solution of the calcined product in Step 1 was stirred at a speed of 350 r / min for 1 hour under a constant temperature water bath at 90°C.

[0020] Step 3. Connect the above to CO 2 The aqueous solution of gas is separated into solid and liquid, and boric acid is added to the obtained solid as a sodium removal agent. The added amount is 0.15% of the solid amount. The dry air is first dried at 115°C, and then at 1350°C, pressure greater than 100Pa, dry air atmosphere , The heating rate is less than 1℃ / min, and the alumina is calcined at a high temperature under the condition of natural cooling, and the sodium oxide in the alumin...

Embodiment 2

[0022] Step 1. Pre-calcin industrial aluminum hydroxide at 500°C for 1 hour, and then add the calcined product to distilled water. The liquid-to-solid ratio of distilled water to alumina in the calcined product is L / S=10, that is, 150g alumina. 1.5L distilled water, set aside;

[0023] Step 2. The aqueous solution of the roasted product in step 1 is heated to 0.15m under the condition of a constant temperature water bath at 90°C 3 / (L·hour) flow into CO 2 Gas while stirring at 350r / min for 1 hour.

[0024] Step 3. Connect the above to CO 2 The aqueous solution of gas is separated into solid and liquid, and aluminum fluoride is added to the obtained solid as a sodium removal agent. The addition amount is 0.05% of the solid amount. First, it is dried at 115°C, and then it is dried at 1350°C and a pressure greater than 100Pa. It is calcined at high temperature under the condition of air atmosphere and the heating rate is less than 1°C / min. After natural cooling, alumina with sodium ox...

Embodiment 3

[0026] Step 1. Pre-calcin industrial aluminum hydroxide at 600°C for 1 hour, then add the calcined product to distilled water. The liquid-to-solid ratio of distilled water to alumina in the calcined product is L / S=10, that is, 130g alumina. 1.3L distilled water, set aside;

[0027] Step 2. The aqueous solution of the roasted product in step 1 is heated to 0.2m in a constant temperature water bath at 90°C 3 / (L·hour) flow into CO 2 Gas while stirring at 350r / min for 1 hour.

[0028] Step 3. Connect the above to CO 2 The solid-liquid separation of the gas aqueous solution, the addition of boric acid as a sodium removal agent to the obtained solid, the addition amount is 0.20% of the solid content, first dry at 115 ℃, and then at 1350 ℃, pressure greater than 100 Pa, dry air atmosphere Calcination at high temperature under the condition of heating rate less than 1°C / min, and natural cooling to obtain alumina with sodium oxide<0.10% (see Table 1).

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Abstract

The invention discloses a method for reducing sodium oxide in aluminum oxide by using carbon dioxide. The method comprises the following steps of: pre-baking aluminum hydroxide and adding a baked product into water to prepare baked product aqueous solution for later use; introducing CO2 gas into the baked product aqueous solution and fully stirring; adding a small number of sodium removing agents into the baked product aqueous solution into which the CO2 gas is introduced; performing liquid-solid separation; drying to obtain a solid; calcining the solid at a high temperature; and naturally cooling to obtain low-sodium aluminum oxide. By the method, the cost for manufacturing the high-temperature low-sodium aluminum oxide can be reduced, the variation in product performance caused by the sodium removing agent can be reduced, and a new approach is discovered for utilization of the carbon dioxide.

Description

Technical field [0001] The invention relates to a high-temperature alumina production process, in particular to a method for reducing sodium oxide in alumina by using carbon dioxide. Background technique [0002] High-temperature alumina is mainly used for refractory materials, automobile spark plugs, electronic substrates, and tools due to its high melting point (2040℃), high hardness, strong chemical inertness, excellent electrical insulation, good thermal stability, and strong wear resistance. , Engineering machinery parts and raw materials for the production of high alumina ceramics, and its prospects are very broad. [0003] Na 2 O content is an important technical indicator of high-temperature alumina. This is due to the fact that Na 2 The level of O content directly affects the strength and fire resistance of the product, and ultimately affects the appearance and use of the product. Usually the higher the alkali content, the α-Al 2 O 3 The lower the phase conversion rate, t...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C01F7/30C01F7/46
Inventor 李韶辉薛忠秀齐波张之强周晓燕李颍
Owner 中铝山东有限公司
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