Open-cell mullite ceramic foams derived from porous geopolymer precursors with tailored porosity

Porous geopolymer precursors were firstly prepared by the direct foaming method using bauxite, fly ash (FA), and metakaolin (MK) as raw materials, porous mullite ceramics after ammonium ion exchange then high-temperature sintering. The effects of chemical agent concentration, ion-exchange time, sintering temperature on geopolymer-derived studied, optimal preparation parameters found. Studies have shown that concentration blowing had great influence open porosity (q) cell size distributions samples, which in turn affected their compressive strength (?). Duration no obvious effect sintered amount phase increased with increase temperature. Mullite foams, possessing an open-celled structure, closely resembling starting geopolymers produced directly foaming, obtained firing at high temperatures. Stable (3Al2O3·2SiO2) ceramic foams total (?) 83.52 vol%, 83.23 1.72 MPa 1400 ? for 2 h air without adding any additives commercial MK, FA materials.