A Study of Stabilization and Recycling for Aluminum Dross

Abstract

In this study, a recycling process for stabilized secondary aluminum dross is proposed. Calcium oxide-containing materials, such as de-sulfur slag produced from steel manufacturing process, are used as stabilizing agents for secondary aluminum dross. The de-sulfur slag was first hydrolyzed. Due to the high content of calcium oxide (about 45%), hydration of de-sulfur slag can produce a solution with strong alkalinity (pH≧12). In the strong alkaline environment, the residual pernicious components in the aluminum dross, such as aluminum nitride, aluminum carbide and metal aluminum, are hydrolyzed and decomposed rapidly, resulting in the stabilization of secondary aluminum dross. The stabilized aluminum dross, therefore, was used as the raw material for preparing concrete bricks. In the subsequent concrete brick manufacturing process, the hydration reaction between stabilized aluminum dross and other raw materials can also produce strong alkaline environment (pH≧12), which further stabilizes the aluminum dross wastes, and produce high-pressure concrete bricks with satisfactory performance.