Template-free route to fabricate extra-lightweight ceramsite with a single large pore structure

Abstract

As a lightweight aggregate, single-pore ceramsite is used in the construction industry, which can effectively solve the problems of traditional porous ceramsite with high bulk density, poor thermal insulation performance and easy leakage. However, preparing single-pore ceramsite by template method brings high cost, complicated process, and serious pollution problems. To overcome these challenges, in this work, we used copper tailings (60 wt%) and clay (40 wt%) as raw materials to prepare extra-lightweight single-pore ceramsite by template-free method. By adding 0.7 wt% SiC to the raw material and sintering at 1180 °C for 15 min, the extra-lightweight single pore structure with 200 density class in GB/T 17431.1–2010 can be obtained. Based on the thermodynamics and the sintered morphology, the mechanism of the single-pore structure formed by the pores sealed by the liquid phase is summarized. Template-free method is beneficial to save the preparation cost, simplify the process flow and reduce carbon emissions. As a result, template-free method provides a new, green, economical, and simple way for single-pore ceramsite production.