Waste‐bearing foamed ceramic from granite scrap and red mud

Abstract

Using granite scrap and red mud as raw materials, SiC as foaming agent, powder sintering method was used to prepare closed‐pore foamed ceramic. The effects of the ratio of red mud and granite scrap, foaming agent content, sintering temperature and holding time on the crystalline phase, pore structure, and performance of foamed ceramic were systematically studied. The results showed that, when the content of red mud was 10 wt%, together with 1.0 wt% SiC addition, the heating rate was 5°C/min, the foamed ceramic sintered at 1130°C for 30 min exhibited optimal properties, including bulk density of 483.11 kg/m3, porosity of 77.27%, compressive strength of 1.62 MPa and water absorption of .49%. Based on these properties, it possessed broad potential application prospects in the fields of sound and thermal insulation, lightweight construction materials. In this study, the utilization ratio of industrial solid waste was 100%, realized the comprehensive utilization of granite scrap and red mud, and provided a new idea to realize their low‐cost utilization by preparing foamed ceramic with associated economic and environmental benefits.

Effect of ceramic matrix compositions on pore structure and properties of lightweight foamed ceramics

“…After heat preservation, as the temperature in the furnace decreases, the high viscosity melt gradually solidifies, and the gas enclosed in the material forms closed pores, thus obtaining foam ceramic products. [1][2][3][4][5] According to reaction principle, it is important to select an appropriate matrix formula, so that it can melt at the violent reaction temperature of foaming agent to form a melt with appropriate viscosity.…”

“…Due to the high viscosity of the melt, the pressure generated by the gas cannot overcome the surface tension of the melt, thus preventing the gas from escaping and increasing the gas content in the sample, resulting in the expansion of the whole material. After heat preservation, as the temperature in the furnace decreases, the high viscosity melt gradually solidifies, and the gas enclosed in the material forms closed pores, thus obtaining foam ceramic products 1–5 . According to reaction principle, it is important to select an appropriate matrix formula, so that it can melt at the violent reaction temperature of foaming agent to form a melt with appropriate viscosity.…”