Morphology-control techniques for preparing aluminum hydroxide via wet chemical synthesis

Abstract

Flake aluminum hydroxide was prepared via neutralization with ammonia and aluminum nitrate solutions containing alumina at a concentration of 10 g/L. Meanwhile 0.5 g/L acetic acid was added to the solution as a shaping additive. The morphology control of neutralization allowed for the production of columnar and flake submicron aluminum hydroxide via precipitation in the Bayer process, which is widely used in alumina refineries. Finally, three morphology-control techniques were developed as followed: (1) during the growing of the crystal seed, the reaction solution should be maximally stabilized. Increased stable condition duration resulted in improved aluminum hydroxide morphology; (2) aluminum hydroxide morphology changed when different anions and additives were used in the reaction solution; and (3) separation of the nucleation stage and growing-up stage afforded aluminum hydroxide with perfect morphology.