The Enhanced Formation of Magnesium-Silica-Hydrates (M-S-H) Phase in Magnesia Castables

Xu Yibiao, Zhang Yu, Li Yawei, Sang Shaobai

The State Key Laboratory of Refractories and Metallurgy, Wuhan University of Science and Technology, Wuhan 430081/China

Revision 21.04.2017, 09.05.2017

Volume 9, Issue 3, Pages 89 - 92


Magnesium-silica-hydrates (M-S-H) is regarded as an ideal bonding phase in magnesia castables due to its bonding strength and progressive dehydration behaviour over a wide temperature range during the heating-up stage. In this work, the effect of addition of sodium silicate solution and caustic magnesia powder on the formation of magnesium-silica-hydrates (M-S-H) in magnesia castables was investigated by means of XRD, FTIR and SEM. The results showed that M- S-H product was promoted to form in MgO–SiO2–H2O system with the increase of curing time as well as in the presence of sodium silicate and caustic magnesia. Finally, the cold crushing strength and cold modulus of rupture of magnesia castables were improved by combination addition. The improvement was attributed to the enhanced formation of M-S-H bonding phase. In addition, it also improved the explosion resistance of magnesia castables.


magnesium-silica-hydrates (M-S-H), magnesia castables, sodium silicate, caustic magnesia


[1] Silva, W.M.; Aneziris, C.G.; Brito, M.A.M. : Effect of alumina and silica on the hydration behaviour of magnesia-based refractory castables. J. Amer. Ceram. Soc. 94 (2011) 4218– 4225 [2] Innocentini, M.D.M.; Cardoso, F.A.: Drying stages during the heating of high-alumina, ultra-low-cement refractory castables. J. Amer. Ceram. Soc. 86 (2003) 1146–1148*3] Szczerba, J.; Prorok, R.: Influence of time and temperature on ageing and phases synthesis in the MgO-SiO2-H2O system. Thermochim. Acta 567 (2013) 57–64 [4] Zhang, T.; Liang, X.; Li, C.: Control of drying shrinkage in magnesium silicate hydrate (MS- H) gel mortars. Cem. Concr. Res. 88 (2016) 36–42 [5] Marmol, G.; Savastano, H.; Tashima, M.M.: Optimization of the MgO-SiO2 binding system for fiber-cement production with cellulosic reinforcing elements. Mater. Design 105 (2016) 251–261 [6] Jin, F.; Al-Tabbaa, A.: Thermogravimetric study on the hydration of reactive magnesia and silica mixture at room temperature. Thermochim. Acta 566 (2013) 162–168 [7] Wei, J.; et al: Reaction products of MgO and microsilica cementitious materials at different temperatures. J Wuhan Univ. Technol.-Mater. Sci. Ed. 26 (2011) 745–748 [8] Souza, T.M.; Luza, A.P.; Santos Jr., T.: Phosphate chemical binder as an anti-hydration additive for Al2O3-MgO refractory castables. Ceram. Int. 40 (2014) 1503–1512 [9] L. T. Zhuravlev: The surface chemistry of amorphous silica, Zhuravlev model, Colloid Surf. APhysicochem. Engin. Asp. 173 (2000) 1–38 [10] Tognonvi, M.T.; Soro, J.: Physico-chemistry of silica/Na silicate interactions during consolidation. Part 2: Effect of pH, J. Non-Cryst. Solids, 358 (2012) 492–501 [11] Jin, F.; Al-Tabbaa, A.: Strength and hydration products of reactive MgO-silica pastes. Cement Concrete Comp. 52 (2014) 27–33 [12] Dominik, N.; Kasper, E.R.; Emilie, L.: Properties of magnesium silicate hydrates (M-S-H). Cem. Concr. Res. 79 (2016) 323–332 [13] Zhang, T.; Vandeperre, L.J.; Cheeseman, C.R.: Formation of magnesium silicate hydrate (MS- H) cement pastes using sodium hexametaphosphate. Cem. Concr. Res. 65 (2014) 8–14 [14] Myhre, B.: Microsilica-gel bond castables for rapid heat-up. RCD 48th Ann. Symposium, St Louis, USA, March 28–29, 2012


Göller Verlag GmbH