Introduction of High Purity Alumina Production Method

    At present, there are two more commonly used methods for producing high-purity alumina, one is the production of aluminum powder and water by the hydrolysis method. Metal aluminum blocks and strips should be processed into metal powder with metal tools. Although metal knives are very hard alloys, there are still metals such as iron that have to be ground down and enter the water to be hydrolyzed with aluminum powder. For example, aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconium hydroxide, etc. are obtained. These are hydroxides and inorganic substances that cannot be filtered out. There is also no way to membrane separation rectification. Therefore, the purity of these products is up to 99.99%.

    The second method is the aluminum alkoxide method. The purity of the aluminum alkoxide method is 1-2 orders of magnitude higher than that of the direct hydrolysis method of metal aluminum, the aluminum sulfate ammonia method, and the Bayer method. First of all, the aluminum alkoxide method uses five 9-metal aluminum blocks to react. Because the metal aluminum reacts quickly with isopropanol butanol and ethanol, it does not need to be processed into aluminum powder with tools, which avoids the contamination of iron caused by tool processing. Secondly, after obtaining the metal aluminum ethoxide and aluminum isopropoxide, it is a metal organic compound, which can be rectified at 230-250 degrees, and the front fraction and bottom fraction impurities can be removed, and the main flow stage is collected to obtain high-purity aluminum alkoxide liquid. Aluminum alkoxide is vaporized and condensed to obtain a liquid. Even if the distilled material contains impurities such as iron, nickel, silicon, copper, etc., it will not vaporize and stay at the bottom of the kettle, thus purifying the product, which cannot be achieved by other processes. After the third aluminum ethoxide rectification, it is separated and purified by ceramic membrane (five 9 alumina ceramic membrane purification) at 230 degrees to remove impurities such as potassium, sodium and zinc for further purification. After two purifications. The aluminum alkoxide is then hydrolyzed with high-purity water, this is the same as the others. Then the ceramic membrane is used to continue the separation at 150-160 degrees to remove impurities and then wash and purify. This process requires alcohol, high temperature, high pressure, and high cost. This method is used by Sumitomo Japan, domestic Jingrui New Materials, the United States, Germany and other 5n alumina raw material production companies