Eco-friendly preparation of self-bonding materials from natural aeolian sand and secondary aluminum dross for sustainable desert construction

Abstract

Desert areas pose challenges for building construction due to extreme temperatures, low humidity, and water scarcity. These factors contribute to the rapid drying of self-bonding materials, leading to poor stability of materials. This study aims to address these issues through a novel approach involving the collaborative utilization of natural aeolian sand (NAS) and secondary aluminum dross (SAD) for the synthesis of self-bonding materials. By utilizing CaO as an alkali activator, NAS, and SAD are subjected to mechanical grinding, leading to the successful production of self-bonding materials for the first time. The results indicated that when the ball grinding rotational speed was 550 rpm, the mass ratio of NAS to SAD was 1:1, and 5% calcium oxide was added, a 360-day compressive strength of 8.57 MPa was achieved for self-bonding materials. Under the synergistic action of mechanical collisions and high temperature, the mineral lattice of SAD was defected, and amorphous substances was appeared, the majority of the Si-O chemical bonds and Al-N bonds were broken by alkaline attack, forming a more stable structure (Si-O-Al). This approach enables the full-volume materialization of hazardous and bulk solid wastes while opening up new possibilities for municipal building materials in desert areas. Furthermore, the proposed method provides an economically viable and environmentally friendly solution for the treatment of 1.3 million km² of desert and two million tons of SAD in China.