Addition of Ammonium Molybdate in Geopolymer Formulation

Abstract:

Geopolymers are inorganic materials obtained by the alkaline activation of aluminosilicate sources. The ammonium molybdate could be used as a complexant for silica in order to complex the siliceous species in the alkaline solution. According to this, the aim of this work is to control the siliceous species and to understand the role of ammonium molybdate as a complexing agent acting on the formation of the different networks. To do this, additions of ammonium molybdate (up to 0.32% molar) in the silicate solution were realized along the formulation of geopolymer using two metakaolins. The results highlight that the addition of ammonium molybdate in geopolymer results in a decrease of the shrinkage at high temperature. Moreover, X-ray diffraction data and SEM after calcination show that geopolymers without ammonium molybdate form two phases (KAlSi₂O₆ and KAlSiO₄) while with additions of molybdate, there were only the phase KAlSi₂O₆ associated with Al₂O₃ doped Mo and K₂Mo₂O₇. Finally, SEM observations show that additions of ammonium molybdate seem to favor crystallization. The results allow to evidence the role of molybdate in the control of the polycondensation reaction in order to influence the formation of specific network

• Periodical: Advances in Science and Technology (Volume 92)
• Pages: 8-13
• DOI: https://doi.org/10.4028/www.scientific.net/AST.92.8
• Online since: October 2014
• Authors: Laëticia Vidal, Emmanuel Joussein, Joseph Absi, Sylvie Rossignol*
• Keywords: Ammonium Molybdate, Geopolymer, Heat Treatment

References

[1] A. Autef, E. Joussein, G. Gasgnier, S. Rossignol, Role of the silica source on the geopolymerization rate, J. of Non-Crystalline Solids, 358 (21) (2012) 2886-2893.

DOI: 10.1016/j.jnoncrysol.2012.07.015

[2] J. Davidovits, Geopolymer: Chemistry and Applications, second ed., Institut géopolymère, St-Quentin, (2008).

[3] A. Autef, Formulation géopolymère : influence des rapports molaires Si/K et Si/Al sur les réactions de polycondensation au sein de gels aluminosilicatés, PhD thesis, Université de Limoges, (2013).

[4] E. Prud'homme, P. Michaud, E. Joussein, A. Smith, C. Peyratout, I. Sobrados, J. Sanz, S. Rossignol, Geomaterial foams: Role assignment of raw materials in the network formation, J. of Sol-Gel Science and Technology, 61 (2) (2012) 436-448.

DOI: 10.1007/s10971-011-2644-z

[5] A. Autef, E. Joussein, A. Poulesquen, G. Gasgnier, S. Pronier, I. Sobrados, J. Sanz, S. Rossignol, Influence of metakaolin purities on potassium geopolymer formulation: the existence of several networks, J. of Colloïd and Interface Science, 408 (1) (2013).

DOI: 10.1016/j.jcis.2013.07.024

[6] P. He, D. Jia, M. Wang, Y. Zhou, Thermal evolution and crystallization kinetics of potassium-based geopolymer, Ceramics International, 37 (1) (2011) 59. 63.

DOI: 10.1016/j.ceramint.2010.08.008

[7] F. Parmentier, Sur les silicomolybdates, Annales scientifiques de l'E.N.S., 2ème série, 11 (1882) 187-218.

DOI: 10.24033/asens.214

[8] V.W. Truesdale, C.J. Smith, The formation of molybdosilicic acids from mixed solutions of molybdate and silicate, The Analyst, 100 (1975) 203-212.

DOI: 10.1039/an9750000203

[9] P. Sarrazin, B. Mouchel, S. Kasztelan, 95Mo NMR study of the interaction of heptamolybdate solutions with alumina and silica, J. Phys. Chem, 93 (1989) 904-908.

DOI: 10.1021/j100339a069

[10] J-E.A. Otterstedt, M. Ghuzel, J.P. Sterte, Colloidal components in solutions of alkali silicates, J. of Colloid and Interface Science, 115 (1) (1987) 95-103.

DOI: 10.1016/0021-9797(87)90012-9

[11] C.H. Rüscher, E. Mielcarek, Weakening of alkali-activated metakaolin during aging investigated by the molybdate method and infrared absorption spectroscopy, J. of the American Ceramic Society, 93 (9) (2010) 2585-2590.

DOI: 10.1111/j.1551-2916.2010.03773.x

[12] C. Cousi, F. Bart, J. Phalippou, Phase separation and crystallization induced by adding molybdenum and phosphorus to a soda-lime-silica glass, Glass Technology, 45 (2) (2004) 65-67.

[13] G-Q. Zhang, J. Guo, L. He, D. Zhou, H. Wang, J. Koruza, M. Kosec, Preparation and microwave dielectric properties of ultra-low temperature sintering ceramics in K2O-MoO3 binary system, J. of the American Ceramic Society, 97 (1) (2014) 241-245.

DOI: 10.1111/jace.12646

[14] J.L. Provis, R.M. Harrex, S.A. Bernal, P. Duxson, J.S.J. Deventer, Dilatometry of geopolymers as a means of selecting desirable fly ash sources, J. of Non-Crystalline Solids, 358 (16) (2012) 1930-(1937).

DOI: 10.1016/j.jnoncrysol.2012.06.001

[15] T. Coradin, D. Eglin, J. Livage, The silicomolybdic acid spectrophotometric method and its application to silicate/biopolymer interaction studies, Spectroscopy, 18 (4) (2004) 567-576.

DOI: 10.1155/2004/356207

[16] J. Dou, H.C. Zeng, Targeted synthesis of silicomolybdic acid (Keggin acid) inside mesoporous silica hollow spheres for Friedel-Crafts Alkylation, J. of the American Chemical Society, 134 (39) (2012) 16235-16246.

DOI: 10.1021/ja3055723

[17] L. Bi, E. Wang, R. Huang, Synthesis, properties and crystal structure of a novel organic-inorganic salt of 12-silicomolybdate, (C2H5NO2)3. 5H4SiMo12O40∙8. 5H2O, J. of Molecular Structure, 569 (1-3) (2001) 81-88.

DOI: 10.1016/s0022-2860(01)00435-5