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Abstract

The method of the invention provides a geopolymeric binder in powder, used for the ultra rapid treatment of materials, soils or mining tailings, containing toxic wastes. The geopolymeric binder has a setting time equal to or greater than 30 minutes at a temperature of 20.degree. C. and a hardening rate such as to provide compression strengths (Sc) equal to or greater than 15 MPa, after only 4 hours at 20.degree. C., when tested in accordance with the standards applied to hydraulic binder mortars having a binder/sand ratio equal to 0.38 and a water/binder ratio between 0.22 and 0.27. The preparation method includes the following three reactive constituents: a) an alumino-silicate oxide (Si.sub.2 O.sub.5,Al.sub.2 O.sub.2) in which the Al cation is in (IV-V) coordination as determined by MAS-NMR analytical spectroscopy for .sup.27 Al; b) a disilicate of sodium and/or potassium (Na.sub.2,K.sub.2)(H.sub.3 SiO.sub.4).sub.2 ; c) a silicate of calcium where the molar ratios between the three reactive constituents being equal to or between ##EQU1## where Ca.sup.++ designates the calcium ion belonging to a weakly basic silicate of calcium whose atomic ratio Ca/Si is lower than 1.

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First Claim