tailieunhanh - Influence of synthesis factors on properties of geopolymers based on red mud and rice husk ash

In this paper, the effect of mixing ratio of raw materials, curing temperature and time on geopolymerization between red mud and rice husk ash were investigated. The results showed that the optimum conditions were SiO2/Al2O3 ratio of 4 and Na2O/Al2O3 ratio of , curing temperature of 100 oC and curing time of 24 hours. The compressive strength, bulk density, total shrinkage of the obtained product were MPa, , 15 %, respectively that met requirement of unsintered bricks using for construction. | Vietnam Journal of Science and Technology 55 (4) (2017) 461-474 DOI: INFLUENCE OF SYNTHESIS FACTORS ON PROPERTIES OF GEOPOLYMERS BASED ON RED MUD AND RICE HUSK ASH Tran Ngoc Tuyen1, *, Nguyen Duc Vu Quyen1, Ho Van Minh Hai1, Dang Xuan Tin1, Tran Ngoc Quang2 1 Department of Chemistry, College of Sciences, Hue University, 77 Nguyen Hue Str., Hue city 2 Department of Environmental Science, College of Sciences, Hue University, 77 Nguyen Hue Str., Hue city * Email: trntuyen@ Received: 27 February 2017; Accepted for publication: 3 July 2017 ABSTRACT In this paper, the effect of mixing ratio of raw materials, curing temperature and time on geopolymerization between red mud and rice husk ash were investigated. The results showed that the optimum conditions were SiO2/Al2O3 ratio of 4 and Na2O/Al2O3 ratio of , curing temperature of 100 oC and curing time of 24 hours. The compressive strength, bulk density, total shrinkage of the obtained product were MPa, , 15 %, respectively that met requirement of unsintered bricks using for construction. Keywords: red mud, rice husk ash, geopolymerization. 1. INTRODUCTION Geopolymer which is amorphous appears to be a potential alternative to the classic hydraulic binders. The exothermic reaction of geopolymerization generates a structure similar to zeolites [1] that is mainly produced from the reaction between metakaolin (source of Si and Al) and hydroxides or alkaline silicate solutions [2, 3, 4]. According to D. Kim et al. [5], geopolymers can be classified into two major groups: (i) pure inorganic geopolymers and (ii) organic containing geopolymers. The geopolymerization mechanism involves Si and Al dissolution from the starting materials and forms available polysialate units (., sialate [–Si–O– Al–O–], sialate siloxo [–Si–O–Al–O–Si–O–] or sialate disiloxo [–Si–O–Al–O–Si–O–], depending on the Si/Al ratio) cross-linked [AlO4] and [SiO4] tetrahedral units, with .