Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 2

Liczba wyników na stronie

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych: 1.13 nm tobermorite

Sortuj według:

Ogranicz wyniki do:

Influence of CaO reactivity on the formation of low-base calcium silicate hydrates

Baltakys K., Prichockiene E.

Materials Science Poland

2010

Vol. 28, No. 1

295--304

The influence of CaO reactivity on the formation of calcium silicate hydrates in the CaO-SiO2onH2O-H2O system has been determined when the CaO/SiO2molar ratio was equal to 0.83 and 1.0. In a pure CaO-SiO2onH2O-H2O system, with CaO/SiO2 = 0.83, C-S-H (I) is rather stable, and at 175 °C, even after 72 h, only partially recrystallizes into 1.13 nm tobermorite. Meanwhile, in the mixtures with less reactive CaO (96%), the stoichiometric composition (CaO/SiO2) of products of the synthesis varies from 0.66 to 0.83. When the CaO/SiO2 molar ratio in the initial mixture is equal to 1.0, the CaO reactivity has a significant effect on the composition of products forming in hydrothermal conditions. The products of the syntheses were characterized by X-ray diffraction analysis, simultaneous thermal analysis and Fourier transform infrared spectroscopy.

Gyrolite Formation in CaO–SiO2źnH2O–gamma-Al2O3–Na2O–H2O System under Hydrothermal Conditions

Baltakys K., Siauciunas R.

Polish Journal of Chemistry

2007

Vol. 81, nr 1

103-114

The influence of gamma-Al2O3 and Na2O additives on the gyrolite formation process in the CaO–SiO2źnH2O–H2O mixture has been examined. It has been proved that gamma-Al2O3 is not recommended for the synthesis of gyrolite, because Al3+ ions stimulate the formation of C-S-H(I) and 1.13 nm tobermorite (where C – CaO, S – SiO2 and H – H2O). Na2O positively affects the formation of gyrolite: this compound is formed already after 8 hours of isothermal curing at 200 graduate C. On the contrary, in the pure mixtures gyrolite formed after only 32 h at 200 graduate C. In order to compare the cation exchange activity of synthesized gyrolite with (Al+Na)-substituted tobermorite, the ion exchange experiments were employed as a test reaction.