As the relentless extraction of antimony ore escalates, the incidence of environmental contamination from its residue, known as antimony tailings (AT), has become a frequent occurrence, garnering widespread concern regarding the management of these residues. Presently, the application of AT is predominantly focused within the realms of construction materials and filling materials. However, due to technological constraints, the rate of utilization is minimal, with the majority being confined to tailings ponds, thereby consuming substantial land resources and presenting a looming environmental contamination hazard. This paper introduces, for the first time, the innovative utilization of AT as a primary raw material in the production of lightweight, waterproof, and eco-friendly foamed concrete. The study delves into the mechanical properties, water resistance, and leaching toxicity of the resulting foamed concrete. The findings indicate that the mechanical properties of the foamed concrete exhibit an initial increase followed by a decrease with the increment of AT content. Optimal comprehensive performance is achieved when the AT content reaches 50%, yielding a compressive strength of 28 MPa, a flexural strength of approximately 5 MPa, a dry density of 110 kg/m3, a wet density of 158 kg/m3, a void index of 1.25, and a softening coefficient of 0.89 after 28 days of standard curing. Furthermore, it is observed that cement and fly ash significantly enhance the solidification of toxic and harmful elements present in AT. This research substantiates the viability of crafting sustainable, environmentally benign, and waterproof foamed concrete by leveraging AT from multiple perspectives.

Foam concrete boasts widespread applications in backfill engineering, energy -efficient insulation components, and road infrastructure. However, the foam concrete with lower density tends to possess the lower stability. The unstable characteristics of foam concrete restricts its application. In this study, the feasibility of employing biochars to increase stability of foamed concrete is investigated. The rheological properties of base mix are carried out to analyze the foam concrete stability. The analysis of water state, interparticle distance and ion concentration are tested to analyze the stabilization mechanisms. Our findings demonstrate that the introduction of corn husk biochar (CHBC) within the base mix expedites flocculation formation, reducing interparticle distance and subsequently elevating the yield stress. Conversely, the inclusion of rice husk biochar (RHBC) diminishes ion concentration, heightening repulsion forces between particles and thereby reducing yield stress of base mix. Higher yield stress exert the higher constraining force and frictional force to the bubbles, thereby decreasing bubble size in fresh foamed concrete, bettering pore structure, compressive strength and foam stability of foamed concrete. Additionally, the increase in CHBC content enhances pore sphericity, potentially attributed to decreased bubble deformation parameters Ca eta.