patents/AU2003255592

Abstract: The invention relates to a geopolymeric cement or binder comprising an amorphous vitreous matrix consisting of a poly(sialate-disiloxo)-type geopolymeric compound, having approximation formula (Na,K,Ca)(-Si-O-Al-O-Si-O-Si-O) or (Na,K,Ca)-PSDS. The inventive cement consists of a mixture of different varieties of polysialates in which the atomic ratio Si:Al varies between 2 and 5.5, the average of the Si:Al atomic ratio values as measured with the electronic microprobe being close to between 2.8 and 3. The remaining components of the geopulymeric cement or binder, such as mellilite particles, aluminosilicate particles and quartz particles, are not used in said Si:Al atomic ratio calculation. The geopolymeric structure of type (K,Ca)-Poly(sialate-disiloxo) (K,Ca)-PSDS is between 50 and 60 %1 more mechanically resistant than that of type (K Cu)-Poly(siulate-siloxo) (K,Ca)-PSS of the prior art.

Claims

CLAIMS: 1. Geopolymeric binder or cement consisting in an amorphous vitreous matrix Cl embedding mellilite particles, aluminosilicate particles and quartz particles, said particles having an average diameter lower than 50 microns, wherein said amorphous CI vitreous matrix comprises a geopolymer compound of the Poly(sialate-di siloxo) type, in with the approximate formula (Na, K, Ca)(-Si-O-Al-O-Si-O-Si-O), or (Na, K, Ca)- in PSDS. 2. Geopolymeric binder or cement according to claim 1, wherein said geopolymer I compound of the Poly(sialate-disiloxo) type consists of a mixture of various varieties of polysialates in which the atomic ratio Si:Al varies between 2 and 5.5, the average of the values of the atomic ratio Si:AI being close to 2.8 to 3 and further wherein the other components of the said geopolymeric binder or cement, such as the mellilite particles, the aluminosilicate particles and the quartz particles, do not enter into the calculation of this atomic ratio Si:Al. 3. Geopolymeric binder or cement according to any one of the claims 1 and 2, wherein in said amorphous vitreous matrix, the average of the values of the atomic ratio Si:(Na, K) as measured by electronic micro beam analysis is close to 6, varying from 3.096 to 9.681. 4. Geopolymeric binder or cement according to any one of the claims 1 to 3, wherein in the said amorphous vitreous matrix, the average of the values of the atomic ratio Si:Ca as measured by electronic micro beam analysis is close to 15, varying from 4.882 to 41.267. Geopolymeric binder or cement according to any one of the claims 1 to 4, wherein the average grain size distribution of calcium mellilite glass, ranges between 15 microns and 25 microns, thus preventing the dissolution of these mellilite particles in the said amorphous vitreous matrix. 6. Geopolymeric binder or cement according to any one of the claims 1 to wherein, during hardening at ambient temperature, calcium mellilite shows a reduction of 10 to 20 by weight of its content in CaO, accompanied simultaneously by an00 O O increase of 100 to 500 (on average 300%) by weight of its content in K 2 0, the Scontent of the other components like SiO 2 A1 2 0 3 and MgO, being unchanged. C 7. Geopolymeric binder or cement according to any one of the claims 1 to 6, wherein said aluminosilicate particles and said quartz particles are found in a weathered granitic rock. 8. Geopolymeric binder or cement according to claim 7, wherein said weathered N granitic rock is a mining waste resulting from the extraction of coal. 8 NI 9. Geopolymeric cement according to any one of the claims 1 to 8, that during its manufacture produces very little of the greenhouse gas, carbon dioxide, CO 2 Geopolymeric binder or cement substantially as described herein with reference to the examples.


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