Preparation of egg-structured ceramsites from molybdenum tailings with improved properties

Conversion of solid waste tailings into building materials is an effective way to turn waste into resources as well as resolve the problems of their accumulation and pollution. Herein, in this paper, light-weight and high strength molybdenum tailings ceramsites (LHMCs) were prepared using molybdenum tailings as the main raw material supplemented with fly ash, sludge, steel slag and other solid wastes by egg-structure (three-layer structure) design and high-temperature sintering. The effects of raw material ratio, amount of carbon powder agent, sintering temperature, and sintering time on the properties of LHMCs were investigated, and the optimal preparation process was proposed to be preheating at 400 °C for 60 min and sintering at 1150 °C for 40 min. The results of the physicochemical properties, morphology, and component analysis of LHMCs show that the LHMCs with egg-structure including porous core, reinforced middle layer, and dense outer layer can significantly increase the strength of the ceramsites under the premise of ensuring the low density of the ceramsites. Meanwhile, the doping of molybdenum tailings improves the physical properties of the ceramsites and achieves the reuse of waste tailings. Importantly, the optimized LHMCs can meet the performance requirements of 900-grade ceramsites. This paper proposes a strategy for the preparation of tailings-doped light-weight and high-strength ceramic building materials, which provides a new idea for the recycling of solid waste.