A porous geopolymer based on aluminum-waste with acoustic properties. (15th July 2019)

• Record Type: Journal Article
• Authors: Leiva, C.; Luna-Galiano, Y.; Arenas, C.; Alonso-Fariñas, B.; Fernández-Pereira, C.
• Is Part Of: Waste management. Volume 95(2019)
• Page Start: 504
• Page End: 512
• Publication Date: 2019-07-15
• Subjects: Fly ash -- Geopolymer -- Aluminum wastes -- Pore generation -- Sound absorption; Hazardous wastes -- Periodicals; Refuse and refuse disposal -- Periodicals; 363.728
• DOI: 10.1016/j.wasman.2019.06.042
• Languages: English
• ISSNs: 0956-053X

Abstract

Graphical abstract: Highlights: A porous material was obtained when fly ash and paval were alkaline activated. Use of aluminium waste as pore generation agent. Pore generation reaction is controlled with proportion fly ash-paval and temperature. Final porous material shows good noise absorption properties. Environmental benefit: use of different industry wastes as raw material. Abstract: Paval, a solid waste stream from the aluminum industry, is used as a pore generation agent in geopolymers. Paval was mixed with coal combustion fly ash, as a geopolymeric precursor, and activated with alkaline solution with the aim of obtaining porous geopolymers to be used as noise barriers. Both geopolymeric and pore generation reactions happen simultaneously. Aluminum from Paval can react with water and OH¯ from the geopolymerization activating solution, producing hydrogen. The hydrogen gas released generates a highly porous material. The influence of the fly ash-paval proportion and the setting temperature on open porosity, compressive strength and noise-absorbing properties were evaluated. To better understand these influences, the setting time, volume expansion and mineral composition were also studied. The obtained results showed that a higher Paval content (fly ash-Paval ratio 50:50) and setting temperature (70 °C) produced a lower setting time and higher volume expansion, increasing the open porosity and improving acoustic properties, but reducing the compressive strength. The material manufactured under these conditions showed similar amorphous phase content to the non-porous geopolymers made without Paval. On the other hand, the obtained materials did not raise environmental concerns in a normalised leaching test.