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Open AccessArticle

Experimental Evaluation of Efficient Si Dissolution from Perlite at Low Level Activator’s Concentration

School of Mining and Metallurgical Engineering, National Technical University of Athens, 157 80 Athens, Greece
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Minerals 2018, 8(4), 160; https://doi.org/10.3390/min8040160
Received: 20 March 2018 / Revised: 29 March 2018 / Accepted: 30 March 2018 / Published: 14 April 2018
(This article belongs to the Special Issue Geopolymers)
This paper deals with the Si dissolution of fine perlite in alkaline solutions for the determination of the SiO2/Na2O mass ratio in the aqueous phase of geopolymer slurries. In the present work, the effect of the main synthesis parameters such as NaOH concentration and curing temperature on the setting time of the paste were studied. The obtained results showed that the inorganic polymer pastes present fast hardening at low concentrations of NaOH solutions for both 70 and 90 °C. This observation was also identified by the Si dissolution study of perlite pastes as a function of different concentrations of NaOH solutions and different solid to liquid ratios of the slurries, under a constant temperature. The optimum synthesis conditions for geopolymer pastes proved to be a low initial NaOH concentration in the alkaline phase (2–4 M NaOH), where the fast hardening of the paste was attributed to the high SiO2/Na2O mass ratio, enhancing the polycondensation phenomena and promoting the geopolymerization process. View Full-Text
Keywords: geopolymerization; inorganic; perlite; alkali activation geopolymerization; inorganic; perlite; alkali activation
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Tsaousi, G.-M.; Douni, I.; Panias, D. Experimental Evaluation of Efficient Si Dissolution from Perlite at Low Level Activator’s Concentration. Minerals 2018, 8, 160.

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