Some aspects of Silicate bonding with and without CO2

Abstract

The paper embodies results of comprehensive investigation work carried out on the hardening characteristics of silicate bonded sands with and without CO2, so as to assess the possibilities of effecting economics in the CO2 process of hardening moulds and cores by partial or total elimination of CO2 by other gases such as oxygen, nitrogen and atmospheric air. The properties obtained in each case were compared with those exhibited by the conventional oil sand cores. It was found that any attempt to dilute the CO2 by air, oxygen or nitrogen tends to lower strength values of the sand mixtures. When air or oxygen is passed alone, the sand mix does not develop any strength at all. While hardening the silicate bonded sand by the application of heat alone, the binder requirement was more than when the sands were hardened by CO2 or a mixture of CO2 or a mixture of CO2 with other gases. A comparative study of the strength value obtained with silicate boned and dried specimens were comparable in the case of dried oil sand specimens. Addition of sources along with sodium silicate imparted still higher values of compressive strength.