| 摘要 |
<p>Alkali metal silicates having a SiO2/alkali oxide wt. ratio of at least 4:1, esp. suitable for the manufacture of rigid foams resistant to water, are produced by mixing a solution of an alkali metal silicate (50-70% water) with a finely divided silica in a ratio at least equal to that of the desired product, at ambient temp. on an elevated temp. (up to or above the swelling temp.). This method is superior to the conventional melting of an alkali metal silicate with sand.</p> |
