| 摘要 |
The process described makes it possible to obtain a geopolymer cement whose manufacture takes place without release of CO2 gas discharged into the atmosphere and taking part in the greenhouse effect on the earth's climate. The process of preparation includes the following three reactive components: a) an aluminosilicate {9 [Si2O5,Al2O2], [Si2O5,Al2(OH)3 ]}, or, to simplify in what follows: (Si2O5.Al2O2) IV-V, having the Al cation in (IV-V) coordination as determined by the spectrum from analysis using nuclear magnetic resonance MAS-NMR for <27>Al; b) a sodium and/or potassium alkali metal melilite (Ca,Na,K)2[(Mg,Fe<2+>,Al,Si)3O7]; c) a calcium melilite Ca2[(Mg,Fe<2+>,AlSi)3O7]. During the alkaline activation of the said cement, a sodium and/or potassium alkali metal disilicate, (Na2,K2)(H3SiO4)2 and a calcium disilicate Ca(H3SiO4)2 are formed in situ, with the result that the molar ratios of the reactive components are equal to or included between <IMAGE> and <IMAGE> The curing of the geopolymer cement by alkali metal activation corresponds to the formation of a geopolymer of (Ca,Na,K)-poly(sialate-siloxo) type of formula varying between <IMAGE> and <IMAGE>
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