To heat a substance to a temperature where it dissociates, for example the heating of calcite (CaCO3) to form CaO and CO2. If clay is calcined, hydroxyl groups are removed from structural constituents and plasticity is destroyed.
To heat a substance to a temperature where it dissociates, for example the heating of calcite (CaCO3) to form CaO and CO2. If clay is calcined, hydroxyl groups are removed from structural constituents and plasticity is destroyed.
An obsolete varietal term for biotite.
An obsolete varietal term for clintonite.
CAH phases are widely used in the Portland cement industry to enhance the hardening effect of Portland cement. For example, “celite” (Ca3Al2O6, “C3A”) is a non-hydrated calcium aluminate and a CAH phase, as is tetracalciuminate (Ca4Al2O7. 19H2O), a hydrated CAH phase. Lime (CaO) has been used for centuries as a stabilizer for soft clay treatment and improvement. It is generally believed that lime can slowly react with clay minerals to produce CSH and CAH phases that act as binders to contribute to the strength development of clayey soils. Cf., calcium silicate hydrate (CSH) phases
Calcium silicate (CS) phases are common to clinker. CS phases are mainly formed by heating calcium carbonate (e.g., limestone for Ca) together with aluminum silicate (e.g., any available clay minerals for Si, Al) phases to temperatures to >1200oC. In practice, often marls, which are low in cost, are used as they combine carbonates and 2:1 layer phyllosilicates. Typical CS phases are “alite” (Ca3SiO5, “C3S”), “belite” (Ca2SiO4, “C2S”), or “celite” (Ca3Al2O6, “C3A”). These phases are responsible for the hardening effect of cement as they hydrate under the addition of water forming CSH phases.
Cf., calcium silicate hydrate (CSH) phases, clinker
CSH phases are formed from calcium silicate (CS) phases [e.g., “alite” (Ca3SiO5, “C3S”), “belite” (Ca2SiO4, “C2S”), jennite (Ca9Si6O18(OH)6·8H2O) and tobermorite (Ca5Si6O16(OH)2·4H2O or Ca5Si6(O,OH)18·5H2O)] by hydration, and these phases are responsible for the hardening effect of cement. Common CSH phases are calcium silicate hydrate (CSH) and ettringite (Ca6Al2[(OH)12(SO4)3] . 26H2O). Lime (CaO) has been used for centuries as a stabilizer for soft clay treatment and improvement. It is generally believed that lime can slowly react with clay minerals to produce CSH and CAH phases that act as binders to contribute to the strength development of clayey soils.
Cf., calcium aluminate hydrate (CAH) phases, clinker, calcium silicate (CS) phases, hardening
A commercial product consisting of sodium phosphate sometimes used as a dispersing agent for clays in aqueous suspensions. In this application, sodium phosphate buffers the solution and phosphate ions preferentially adsorb to clay edges. Both processes aid in dispersion of the clay. Calgon® is a registered trademark of The Calgon Corporation.
A commercial product composed of silicon carbide that is used as an abrasive in cutting, grinding and polishing applications. Carborundum® is a registered trademark of The Carborundum Corporation.
Carlosturanite is a rare antigorite-like mineral that apparently contains vacant tetrahedral sites which interrupt the continuity of the tetrahedral sheet without affecting the continuity of the octahedral sheet (Mellini et al., 1985). The structure is thus similar to a modulated serpentine. To maintain charge balance, OH groups substitute for O atoms. The generalized formula is M21[T12O28(OH)4](OH)30. H2O, where M = Mg, Fe3+, Mn2+, Ti4+, and Cr3+, and T = Si, Al. Alberico (1998) showed that there are problems with the model of Mellini et al. (1985), and suggested the need to reexamine the structure. Important occurrences are related to low grade metamorphic (serpentinite) environments.
Cf., antigorite
See hydrotalcite group.