| 摘要 |
It is an object of the present invention to provide an alkali silicate aqueous solution having intermediate characteristics between water glass and colloidal silica and having a high molar ratio (SiO2/(A2O+B)) (A: alkali metal, B: NH3), a high silicon content and a high anionic activity. The alkali silicate aqueous solution according to the invention has the properties: (A) the molar ratio of silicon to an alkali (SiO2/(A2O+B)) is in the range of 4 to 30, and (B) the silicon concentration in terms of an oxide (SiO2 concentration) is in the range of 6.8 to 30 % by weight. The process for preparing an alkali silicate aqueous solution according to the invention comprises dealkalizing a starting alkali silicate aqueous solution by means of an electro-dialysis device, and then optionally concentrating the dealkalized solution by a reverse osmosis membrane method. <IMAGE>
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