Influence of temperature and acid on time and set of silicic acid gels

The underlying purpose of this research was to gain a further insight into the mechanism of the setting of silicic acid gels. The primary purpose, however, was to study the effect upon the heat of activation of the substitution of the weak acids, heretofore used almost entirely in the work done at Union College on these gels, by certain strong acids. The acids employed in this research were hydrochloric, nitric and sulphuric. Several gels were prepared from a standard silicate solution and each of these acids. Measurements of the time of set and pH were taken for each gel. Four different temperatures were used. All of the gels studied fell in the range of pH extending from 3 to 6. From the data obtained values of the heat of activation were calculated