Preparation of High-purity Alumina via Hydrolysis of Aluminum Isopropoxide after Desilication with Lanthanum Oxide

Abstract

High-purity alumina refers to ultra-fine alumina powder with a purity exceeding 99.99% and a uniform particle size. This material exhibits excellent corrosion resistance, high-temperature resistance, wear resistance, and oxidation resistance. Owing to the high silicon content of alumina prepared by means of the alcohol-aluminum hydrolysis method, the purity of the alumina is often unsatisfactory. Therefore, in this work, a new method for adding lanthanum oxide to isopropanol in the early aluminum isopropoxide synthesis stage is proposed. When lanthanum oxide was added, the silicon content of the precursor aluminum isopropoxide decreased to 0.0051%.Remove calcium, sodium, magnesium and other impurities by cleaning with hydrochloric acid under an ultrasonic field. The optimal hydrolysis conditions were determined as follows: hydrolysis temperature: 55, hydrolysate concentration: 80%, water to alkoxide ratio: 6:1. The alumina precursor calcined at 1200 yielded a high-purity alumina with a purity level of more than 99.99%, and the particle size reaches 2.037 μm.