Mechanochemical activation of kaolin, pyrophyllite, and talcum and its effect on the synthesis of cordierite and properties of cordierite ceramics

Abstract

The paper examines the mechanochemical activation of starting minerals (kaolin, pyrophyllite, and talcum) and their effect on the solid-phase synthesis and properties of cordierite. Binary oxide compounds (spinel, mullite, enstatite, forsterite) are synthesized. It is established that binary compounds and crystalline silica should be minimized to decrease the synthesis temperature of cordierite. Processes for synthesis and production of cordierite ceramics with lower thermal expansion coefficient ((1.0-1.2) ⋅ 10 -6 °C -1 ) are developed.

Kaolinite-Magnesite Based Ceramics. Part I: Surface Charge and Rheological Properties Optimization of the Suspensions for the Processing of Cordierite-Mullite Tapes

“…The influence of MgCO3 added (3,6, and 12 mass%) on DTA and TG curves of kaolinitic clay are also investigated ( Figure 2c). The curves indicate that increasing of adding MgCO3 form 6 to 12 mass% shifted the maximum of the peak position from 480 to 518 °C due to the residual bonds between the layers leads to the unequal location of OH groups [24]. The DTA and TG curves of KT2 (Figure 2a) indicate several phenomena: (i) A weak endothermic peak below 200 • C associated with a mass loss of 1.4% due to the evaporation of physically adsorbed water (dehydration);…”

“…The most recent study suggests that magnesium oxide had a greater influence on the sodium hexamethaphosphate-kaolin interactions, which have an anti-dispersant performance in the dispersions [23]. Therefore, the MgO is usually obtained by magnesite decomposition at high temperature [24]. In the present work, the effect of magnesite to the aqueous kaolinitic clay dispersion may cause a decrease or increase in the repulsive force interactions between the solid particles in the slurry, which directly affect the rheological parameters of the medium, as well as its pH.…”

Processing and characterization of pure cordierite and zirconia-doped cordierite ceramic composite by precipitation technique

“…6 The mechanochemical activation performed on starting materials kaolin, pyrophyllite and talcum showed synthesis by solid-state reaction occurred at lower sintering temperature, also reported low thermal expansion. 7 Cordierite is not easily obtained by solid-state reactions from oxides, because of its refractory character. Synthetic powders exhibit heterogeneous surface properties and even chemical inhomogenity.…”

Kaolinite-Magnesite Based Ceramics. Part I: Surface Charge and Rheological Properties Optimization of the Suspensions for the Processing of Cordierite-mullite Tapes

“…The influence of MgCO3 added (3, 6, and 12 %.mass) on DTA and TG curves of kaolinitic clay are also investigated ( Fig.2(c)). The curves indicates that increasing of adding MgCO3 form 6 to 12 mass% shifted the maximum of the peak position from 480 to 518 °C due to the residual bonds between the layers leads to the unequal location of OH groups [24]. The specific surface area (SSA) of both samples is reported in Table 1.…”

“…The most recent study, suggests that magnesium oxide had a greater influence on the sodium hexamethaphosphate-kaolin interactions, which have an anti-dispersant performances in the dispersions [23]. Therefore, the MgO is usually obtained by magnesite decomposition at high temperature [24]. In the present work, the effect of magnesite to the aqueous kaolinitic clay dispersion may cause a decrease or increase in the repulsive force interactions between the solid particles in slurry, which directly affect the rheological parameters of the medium, as well as its pH.…”