Fabrication and Characterization of Aluminum Dross-Containing Mortar Composites: Upcycling of a Waste Product

Abstract

Dross is a byproduct of the aluminum production process. At the present time, dross is further processed in rotary kilns to recover the aluminum, and the remaining salt cake is sent to landfills raising environmental concerns. Furthermore, much energy is consumed attempting to recover the aluminum from the dross; this energy usage can be reduced if the dross could be further utilized in a natural cycle (closed loop) as an engineering material. In this study, two types of dross were used as active aggregates in cement paste through a simple conditioning process to strengthen the mortar material. Particle size, weight fraction, as well as origin of the dross material play significant roles of the homogeneity of the microstructure of dross-containing mortar specimens. Mechanical property evaluations revealed the possibility for dross waste to be utilized as filler in mortar, resulting in a 40 % higher flexural strength and a 15 % higher compressive strength compared to pure cement.