Use of the sol-gel method for the production of no cement castables

摘要

The most of commonly used castables are bonded by calcium aluminate cement (CAC). There are also other alternative binders such as phosphates, hydratable alumina, organic bond, colloidal silica, etc. The main reason for replacing traditional hydraulic bond is to reduce calcium oxide content, which mainly causes formation of low melting phases during firing. Thus, mechanical and refractory properties can be deteriorated while calcium aluminate phases are decomposing. Sol-gel method is successfully applied mainly in cement-free (No Cement Castables - NCC) vibratable or self-flowing castables. The most used colloidal sol is colloidal silica sol, especially thanks to relative low price in comparison to alumina and titanium sols. Main aim of this thesis is design of no cement castable based on sol-gel method with emphasis on improving physical-mechanical and refractory properties in comparison to ultra-low cement castable.