The influence of chemical treatment of industrial aluminum hydroxide on its priming activity at precipitation and ability to agglomerate when producing sandy alumina in the Ural alumina refineries. It is shown that the most suitable reagent for activating the priming activity of aluminum hydroxide is the aluminate liquor. After 2-h of aluminum hydroxide treatment in alkaline medium at 90 °C precipitation rate of aluminate liquor is increased by 4-5%. It was revealed that using activated aluminum hydroxide in agglomeration process may reduce -45 μm fraction content from 25 to 5%.