Optimization of activator solution and heat treatment of ground lignite type fly ash geopolymers

Molnár, Zoltán and Szabó, Roland and Rácz, Ádám and Lakatos, János and Debreczeni, Ákos and Mucsi, Gábor (2017) Optimization of activator solution and heat treatment of ground lignite type fly ash geopolymers. IOP CONFERENCE SERIES: MATERIALS SCIENCE AND ENGINEERING (175). pp. 1-8. ISSN 1757-8981


Download (868kB) | Preview


Geopolymers are inorganic polymers which can be produced by the reaction between silico aluminate oxides and alkali silicates in alkaline medium. Materials containing silica and alumina compounds are suitable for geopolymer production. These can be primary materials or industrial wastes, i. e. fly ash, metallurgical slag and red mud. In this paper, the results of the systematic experimental series are presented which were carried out in order to optimize the geopolymer preparation process. Fly ash was ground for different residence time (0, 5, 10, 30, 60 min) in order to investigate the optimal specific surface area. NaOH activator solution concentration also varied (6, 8, 10, 12, 14 M). Furthermore, sodium silicate was added to NaOH as a network builder solution. In this last serie different heat curing temperatures (30, 60, 90°C) were also applied. After seven days of ageing the physical properties of the geopolymer(compressive strength and specimen density)were measured. Chemical leaching tests on the rawmaterial and the geopolymers were carried out to determine the elements which can be mobilized by different leaching solutions. It was found that the above mentioned parameters (fly ash fineness, molar concentration and composition of activator solution, heat curing) has great effect on the physical and chemical properties of geopolymer specimens. Optimal conditions were as follows: specific surface area of the fly ash above 2000 cm2/g, 10 M NaOH, 30o C heat curing temperature which resulted in 21 MPa compressive strength geopolymer.

Item Type: Article
Subjects: T Technology / alkalmazott, műszaki tudományok > TN Mining engineering. Metallurgy / bányászat, kohászat, fémipar
Depositing User: Dr Gábor Mucsi
Date Deposited: 22 Sep 2017 09:00
Last Modified: 22 Sep 2017 09:00

Actions (login required)

Edit Item Edit Item