Sodium silicate solutions from dissolution of glasswastes. Statistical analysis

Abstract

It has studied the solubility process of four different waste glasses (with different particle sizes, <45 µm and>125 µm) in alkaline solutions (NaOH and NaOH/Na 2 CO 3 ) and water as a reference and under different conditions of solubility (at room temperature, at 80°C and a mechano-chemical process). Have established the optimal conditions of solubility and generation of sodium silicates solutions, and these were: the smaller particle size (<45 µm), with NaOH/Na 2 CO 3 solution and with temperature during 6 hours of stirring time. The statistical analyses of the results give importance to the studied variables and the interactions. Through 29 Si NMR MAS it has confirmed the formation after dissolution processes of monomeric silicate, suitable for use as an activator in the preparation of alkaline cements and concretes. RESUMEN: Disoluciones de silicato sódico procedentes del tratamiento de residuos vítreos Estudio estadístico.Se ha estudiado el proceso de solubilidad de cuatro diferentes residuos vítreos (con distintas granulometrías, <45 µm y >125 µm) en disoluciones alcalinas de NaOH y NaOH/Na 2 CO 3 y agua como medio de referencia y bajo distintas condiciones de solubilidad (a temperatura ambiente, a 80°C y con un proceso mecano-químico). Se han establecido las condiciones óptimas de solubilidad y generación de disoluciones de silicato sódico, y estas son: menor tamaño de partícula del residuo vítreo (inferior a 45 µm), con la disolución de NaOH/Na 2 CO 3 y tratamiento térmico a 80°C durante 6 horas de agitación. El análisis estadístico realizado a los resultados obtenidos da importancia a las variables estudiadas y a las interacciones de las mismas. A través de 29 Si RMN MAS se ha confirmado la formación, tras los procesos de disolución, de un silicato monomérico, apto para su utilización como activador en la preparación de cementos y hormigones alcalinos.

Mechanical and microstructural analysis of geopolymer composites based on metakaolin and recycled silica

“…Based on this finding, research has been directed toward the production of alternative silicates to make the geopolymer production process more environmentally sustainable . Several studies have focused on the use of secondary sources of silica that can be obtained from industrial byproducts, such as silica fume (SF), rice husk ash (RHA) and other wastes …”

La activación alcalina de diferentes aluminosilicatos como una alternativa al Cemento Portland: cementos activados alcalinamente o geopolímeros

“…The silicates effect Criado et al (Criado et al, 2008) (Puertas et al, 2012;Torres-Carrasco et al, 2014;Puertas and Torres-Carrasco, 2014;Torres-Carrasco and Puertas, 2015; Mejía et al, 2013) and nano-silica (Rodríguez et al, 2013), which have been also evaluated as a replacement silica source for these alternative activators. Hardjito et al, 2004).…”

Performance at high temperature of alkali-activated slag pastes produced with silica fume and rice husk ash based activators

“…In order to reduce the embodied energy associated with the alkaline activator required to produce alkaliactivated materials, the feasibility of substituting commercial sodium silicates by alternative silicates produced through the chemical reaction between NaOH, glass wastes and amorphous silica sources such as silica fume and rice husk ash has been studied (23)(24)(25)(26)(27)(28)(29). In alkali-activated slag binders (23)(24)(25) the development of higher mechanical strengths and reduced permeability has been identified when using activators based on silica fume and NaOH, compared with materials produced with commercial sodium silicates.…”