ChemInform Abstract: Influence of Seed Crystals on the Formation of Calcium Silicates with the Composition 3 CaO·2 SiO2.

ChemInform Abstract

It is shown that the presence of seed crystals facilitates or enables the formation of kilchoanite (Ca₆((SiO₄)(Si₃O₁₀))) and rankinite (Ca₃Si₂O₇), respectively. The formation temp. of kilchoanite in the hydrothermal synthesis is lowered to about 200 °C by seeding with ∼ 5 wt.% kilchoanite, γ-Ca2SiO4, or Al compounds. Kilchoanite is also obtained by solid state reaction at 700 °C under normal pressure starting from C-S-H(di,poly) containing ∼ 5% kilchoanite. Rankinite is obtained analogously when rankinite itself is used as seed crystal.