Effect of Electrolytes on Solidification of Glass Beads by Hydrothermal Hot-Pressing.

Soda lime glass beads were solidified by hydrothermal hot-pressing at 300°C for a period of 1 hour with NaOH, KOH, NaCl, KCl, Na2SO4, HCl solutions and deionized water, respectively. Shrinkage was monitored during experiment, and the solidified products were examined by SEM-EDX, XRD, FT-IR, TG and Shore hardness tester. The cross-section of the reacted glass bead showed three distinct layers of varying thickness that have undergone different degrees of alteration. The degree of alteration was higher approaching the surface of the glass beads. The surfaces of the glass beads were highly altered, deformed and cemented with each other. The final shrinkage increased in the order of acidic, neutral and alkali solution. The Shore hardness was found to increase with any increase in shrinkage for solutions containing same cation but was higher for Na+ solution than K+ solution. Thermogravimetric results indicated that the water contents in solidified products with K+ solutions were higher than the ones with Na+ solutions. This suggests that the drop in the hardness was caused by the presence of larger amount of water in solidified products with K+ than Na+.