Prepn of high-purity alumina

A high-purity alumina and aluminum hydroxide technology, applied in the preparation of alumina/hydroxide, can solve the problems of serious environmental pollution, low purity, and difficult to control aluminum powder oxidation, and achieve economical advantages and high product purity. , Environmentally friendly effect

Inactive Publication Date: 2002-10-16
河北恒博新材料科技股份有限公司
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Problems solved by technology

[0004] One is the rinsing of Bayer process alumina. Bayer process alumina and aluminum hydroxide contain excessive sodium and silicon. The concentration of these impurities can be reduced by changing the precipitation conditions of aluminum hydroxide or rinsing calcined alumina, but these processes Expensive and unreliable for controlling desired impurity levels
[0005] Chinese patent documents 95103368.9 and 95105843.6 relate to a process for producing alumina and alumina micropowder by salting-out method, the main disadvantages of which are low purity and serious environmental pollution
[0006] Chinese patent document 93110316.9 relates to a high-purity ultra-fine alumina production process and device, and ammonium alum is decomposed to obtain γ-Al1 2 o 3 , and then phase invert to

Method used

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Embodiment

[0038] Example: Put 100g of 0.1mm thick aluminum foil into a 1000ml beaker, add 600ml of 0.5M choline aqueous solution, put it in a constant temperature water bath at 75°C, stir once every 30 minutes with a working stick, and react for 24 hours. At this time, most of the aluminum foil has been converted into aluminum hydroxide powder, and the remaining very small amount of unreacted aluminum foil settles at the bottom of the beaker, and passes through a 100-mesh sieve. The bottom of the sieve is aluminum hydroxide, and the top of the sieve is unreacted aluminum foil. , weighed about 5g after drying, vacuum filtered the aluminum hydroxide, returned the filtrate to the beaker, and calcined the filter cake at 1200°C for 4 hours in a high-temperature muffle furnace to obtain α-Al 2 o 3 Powder 183g.

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Abstract

The present invention features that through the reaction of choline and pure aluminium to produce aluminum cholinide, hydrolyzing cholinide to produce aluminium hydroxide and choline, washing, filtering, calcining and grinding aluminum hydroxide, high-purity alpha alumina is prepared. The present invention has the advantages of high product purity, environment friendship, no pollution, low cost, etc. The high-purity alumina may be used in high-voltage sodium lamp tube, light-emitting RE material, high-grade grinding material, fine ceramics and other fields.

Description

Technical field: [0001] The invention relates to a method for preparing high-purity alumina by chemical reaction using high-purity metal aluminum as raw material. Background technique: [0002] High-purity alumina is mainly used in rare earth fluorescent materials, high-pressure sodium lamps and other special alumina applications such as abrasives, catalysts and structural ceramics. The content of metal impurities in high-purity alumina must be very small (less than 0.01%), sulfide and Chlorides are also harmful. [0003] There are several methods for producing high-purity alumina in the prior art: [0004] One is the rinsing of Bayer process alumina. Bayer process alumina and aluminum hydroxide contain excessive sodium and silicon. The concentration of these impurities can be reduced by changing the precipitation conditions of aluminum hydroxide or rinsing calcined alumina, but these processes Expensive and unreliable for controlling desired impurity levels. [0005] Chi...

Claims

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Application Information

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IPC IPC(8): C01F7/42
Inventor 骆树立
Owner 河北恒博新材料科技股份有限公司
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