Extension of the ‘Inorganic Gel Casting’ Process to the Manufacturing of Boro-Alumino-Silicate Glass Foams

0502509 - ÚFM 2019 RIV CH eng J - Journal Article
Romero, A. R. - Tamburini, S. - Taveri, Gianmarco - Toušek, J. - Dlouhý, Ivo - Bernardo, E.
Extension of the ‘Inorganic Gel Casting’ Process to the Manufacturing of Boro-Alumino-Silicate Glass Foams.
Materials. Roč. 11, č. 12 (2018), č. článku 2545. E-ISSN 1996-1944
EU Projects: European Commission(XE) 642557 - CoACH
Institutional support: RVO:68081723
Keywords : glass recycling * alkali activation * gel casting * glass foams
OECD category: Mechanical engineering
Impact factor: 2.972, year: 2018
https://www.mdpi.com/1996-1944/11/12/2545

A new technique for the production of glass foams, based on alkali activation and gel casting, previously applied to soda-lime glass, was successfully extended to boro-alumino-silicate glass, recovered from the recycling of pharmaceutical vials. A weak alkali activation (2.5 M NaOH or NaOH/KOH aqueous solutions) of fine glass powders (below 70 µm) allowed for the obtainment of well-dispersed concentrated aqueous suspensions, undergoing gelation by treatment at low temperature (75 °C). Unlike soda-lime glass, the progressive hardening could not be attributed to the formation of calcium-rich silicate hydrates. The gelation was provided considering the chemical formulation of pharmaceutical glass (CaO-free) to the formation of hydrated sodium alumino-silicate (N-A-S-H) gel. An extensive direct foaming was achieved by vigorous mechanical stirring of partially gelified suspensions, comprising also a surfactant. A sintering treatment at 700 °C, was finally applied to stabilize the cellular structures.
Permanent Link: http://hdl.handle.net/11104/0294466