Cold-setting refractory composites from cordierite and mullite–cordierite design with geopolymer paste as binder: Thermal behavior and phase evolution

Role of Heat-Treated Laterite on the Strengthening of Geopolymer Designed with Laterite as Solid Precursor

“…However, the final material has still a composite microstructure with a matrix phase having a gel structure where coarse aggregates of unreacted phases are distributed. Their quantities and distribution are parameters that favor the optimization of material properties [50,51]. Since larger zones of the matrix phase are detrimental to strength, this work show that a limited fraction of a heat-treated laterite must be added (30 wt% of LN500) to attain a value of 18.25 MPa that meets the standard mechanical strength [52].…”

Mechanical and microstructural analysis of geopolymer composites based on metakaolin and recycled silica

“…Geopolymer composites have been produced with different types of particles with the aim of modifying their microstructural, mechanical, and thermal properties. Nanopowders of carbon, α‐alumina and mullite nanosilica, cordierite, zircon, quartz and illite clay mineral, refractory particles ground electrical porcelain, hollow ceramic microspheres, chamotte, river sand and vermiculite have been incorporated into geopolymers. The incorporation of α‐Al 2 O 3 in high volumes increases the compressive strength of the geopolymer and the incorporation of 10.5 wt% chamotte particles into geopolymer pastes based on metakaolin decreases the crystallization temperature of the leucite and increases the flexural strength of the composite …”

Improved microstructure and free efflorescence geopolymer binders

“…The starting solid materials used for this work are three natural minerals that are bauxite, kaolin and talc, their chemical and mineralogical characteristics, investigated by inductively coupled plasma Spectroscopy (ICP) and X-ray diffraction, respectively, are presented in Table 1 [15,[20][21][22]. They were grounded in porcelain mortar, dried at 110 °C, and sieved at 75 µm before mixed in specific proportions to be close to the theoretical formula of cordierite and mullite-cordierite Table 2 [15,17]. In a first stage, blends were dry-milled for 4 h. It was followed by a wet milling in porcelain jars for 4 h with the addition of 60 wt% of water.…”

“…For instance, the monolithic geopolymer refractories are mostly constituted of large aggregates of particles, and also finer powder that together form a complex microstructure. In such structure, large filler refractory grains are linked together by a continuous geopolymer matrix that acts as bonding phase, and the whole system is comparable to the so-called grain and bond microstructure; the latter can display several usefulness in thermal insulation and thermal shock refractories [15,16].…”

“…In addition to this objective, expectation to meet future applications of geopolymer binders in refractory materials, since cordierite and mullite present interesting thermomechanical properties at temperature above 1300 °C. We expect that mullite and cordierite phases will effectively recrystallize in materials during using for firing as refractory [15,[17][18][19]. Quantities of each resources were calculated in view to obtain stoichiometry very close to that of both cordierite (Mg 2 Al 4 Si 5 O 18 ) and mullite-cordierite (3Al 2 O 3 .2SiO 2 -Mg 2 Al 4 Si 5 O 18 ) with the weight ratio of 50:50.…”