| 摘要 |
PURPOSE:To facilitate the control of a long gelation time and, at the same time, to improve the strength of the neutral region of an agglomerate, by blending an aq. non-alkaline silicic acid soln. with calcium salt or magnesium salt of phosphoric acid. CONSTITUTION:A grout prepd. by blending an aq. alkaline silicic acid soln., obtd. by treating water glass with an acid, with calcium or magnesium salt of phosphoric acid. The calcium phosphate or magnesium phosphate, particularly dibasic calcium phosphate and dibasic magnesium phosphate have outstanding features that they not only exhibit an effect of promoting the gelation of the aq. non-alkaline silicic soln. despite the fact that they are slightly soluble in water and neutral or slightly acidic but also do not decrease the gelation time to less than several ten minutes or ten-odd minutes. |
