A Study On The Preparation Of High-Purity Alumina Powder From Scrap Aluminum

High-purity alumina powder has become rapid developing industrial fine materials throughout the world due to its surface effect, volume effect, optical and magnetic properties as well as chemical and catalytic properties. It has been widely used in many fields, such as the clothing materials in textile industry, wear-resistant coatings and electrostatic shielding coatings, heat resisting materials in automobile parts and space industry, electrical insulating materials in optoelectronics industry, and IC substrates, advanced ceramics, the translucent alumina sintered body, the phosphor carrier, the catalyst and its carrier, abrasive materials and laser material, etc.One of the essential production resources of the sustainable development of the aluminum industry is the recycled aluminum material. The demands of utilities and other energies for the primary aluminum production are much greater than those for recycling scrap aluminum. Moreover, by recycling scrap aluminum, the pollution of the environment can be reduced greatly, and the cost of producing aluminum alloys can also be reduced. During the processing of aluminum materials, it will inevitably produce scrap aluminum. Thus, the scrap aluminum recycling has been attracted more and more interest across the world. Since there are so many scrap aluminum materials, plus the high-purity alumina powder are being used so extensively, using scrap aluminum to produce high-purity alumina powder will be a promising subject.In this present study, the aluminum isopropoxide was synthesized by using scrap aluminum and isopropanol and the high-purity alumina powder was prepared by using sol-gel method. The surface of the scrap aluminum would be pretreated before the preparation. The mass ratio of aluminum and aluminum chloride, which is the catalyst, is1:10and the addition of isopropanol is excessive. The aluminum isopropoxide was preliminarily purified by using the precipitation method, and then the impurities were separated by centrifugation. At last, the aluminum isopropoxide was re-purified by recrystallization. The prepared pure aluminum isopropoxide was added into the water-alcohol solution (w/w:1/2) and the mixture was stirred for20min, then heated at80℃for20min. The high-purity alumina powder was obtained after the calcination of the precipitates at1200℃for3hours.