Clayey barriers

摘要

The present invention relates to improved clayey barriers, such as compacted clay liners or geosynthetic clay liners, which can be used, among other uses, to isolate waste liquids from the environment. More in particular, the present invention relates to clay which is treated with an anionic polymer and is subsequently dehydrated before it is used as a barrier. The latter improved clays are surprisingly well, and for a long term, protected from chemical attack by aggressive electrolyte solutions present in, for example, sea water or waste liquids.

主权项

1. A method of preparing a hydraulic clayey barrier comprising:
a) wetting a clay by mixing the clay with a solution comprising an anionic polymer to obtain a slurry of clay treated with an anionic polymer, and b) drying the slurry of clay and anionic polymer in order to expel water molecules and adsorb the polymer on the clay surface, wherein said hydraulic clayey barrier has the following characteristics: a basal spacing d>1,235 nm, a liquid limit LL>122%, a swell index SI>26 ml/2 g, a swell pressure SP>50 kPA, a hydraulic conductivity k to CaCl2<3.53 10−11 m/s and to seawater <6 10−10 m/S, a chemico-osmotic efficiency ωCaCl2=1 mM>0.29 and/or a diffusion coefficient D(Cl− or Ca2+)>2.22 10−10 m2/s.