In this study, a foamed ceramics with excellent thermal insulation properties was prepared by high-temperature foaming method using gangue solid waste and feldspar as the main raw materials, MnO₂ as the blowing agent and Na₂B₄O₇ as the flux. The effects of sintering temperature, Na₂B₄O₇ addition and sintering time on the performance of foamed ceramics were experimentally investigated. The results indicate that when the sintering temperature is 1 180 ℃ and the sintering time is 30 min, the prepared foamed ceramics exhibit better overall properties, including lower density, higher porosity, and improved thermal insulation. Further exploration of the foaming mechanism of MnO₂ as a blowing agent reveals that the oxygen generated from the thermal decomposition of MnO₂ at high temperatures effectively promotes pore formation, enhancing the porosity and thermal insulation properties of the foamed ceramics. Additionally, the foamed ceramics not only improves the resource utilization of gangue but also reduces the environmental impact of waste, offering lower production costs and significant potential for energy savings and consumption reduction.