. . . "100 to 20/100.In another embodiment of the invention, an aqueous solution containing about 10% to 60%, preferably about 35% to 50%, by weight of solids of an alkali metal silicate, in particular sodium silicate or potassium silicate, having a SiO.sub.2/M.sub.2 O molar ratio on the order of 1.6 to 3.5, preferably on the order of 1.8 to 2.6 is adsorbed and/or absorbed on a particulate support which" .