The production method of high purity alumina is introduced

To the metal aluminum block, strip, with metal cutter processing into metal powder. Although the metal tool is very hard alloy, but there are still iron and other metals to be ground down, into the water and aluminum powder hydrolysis. Get such as aluminum hydroxide, iron hydroxide, nickel hydroxide, zirconia, etc., these are hydroxides are inorganic substances can not be filtered out. There is no way to separate membrane distillation. So these products are 99.99 percent pure at best.

The second method is the alcohol-aluminium process. The purity of the alcohol-aluminium process is 1-2 orders of magnitude higher than that of the direct hydrolysis of metallic aluminium, the aluminum-sulphate process and the Bayer process. First of all, five 9-metal aluminum blocks are used in the alcohol-aluminum process. Because aluminum reacts quickly with isopropanol butanol and ethanol, there is no need to process aluminum powder with a tool, which avoids the pollution brought into iron by tool processing. The second one is the metal-organic compound, which can be rectified at 230-250 degrees. Impurities in the front and bottom fractions can be removed and the main stream can be collected to obtain the high-purity alcohol-aluminum liquid. The rectified alcohol-aluminum gasification can be condensed to obtain the liquid. Even if there are impurities such as iron, nickel, silicon and copper in the distilled material, they will not vaporize and remain at the bottom of the kettle, thus purifying the product, which is impossible to be achieved by other processes. After the third ethanol-aluminum distillation, the ceramic membrane was separated and purified at 230 degrees (five ceramic membranes of 9 alumina were purified), and impurities such as potassium, sodium and zinc were removed for further purification. It goes through two refinements. Aluminum alcohol hydrolyzes with high purity water, just like anything else. Then the ceramic membrane was used to continue the separation at 150-160 degrees, and the impurities were removed and then washed with water. This process USES alcohols, high temperature, high pressure and high cost. This method is used by Japan's Sumitomo, Domestic Jingrui New Materials, the United States, Germany and other 5N alumina raw material production companies.