Enhancing the green mechanical strength of colloidal silica-bonded alumina castables using a silane coupling agent

摘要

The use of colloidal silica as a binder for refractory castables has attracted great interest in recent years. Nevertheless, the resultant low green mechanical strength of colloidal silica-bonded castables has hindered their application in relevant areas. A silane coupling agent, 3-methacryloxypropyltrimethoxysilane (CH2=C(CH3)COOC3H6Si(OCH3)(3)), normally called KH-570, has been added to colloidal silica-bonded alumina castables to enhance their green mechanical strength. The results show that KH-570 has a positive effect on the green mechanical strength improvement of colloidal silica-bonded alumina ca stables. The reaction between hydration products of KH-570 and the solid particles of colloidal silica (confirmed by Fourier transform infrared spectroscopy (FTIR)) could promote the formation of an organic-inorganic interpenetrating network structure, which is the main reason for the green mechanical strength improvement. Meanwhile, the water consumption by KH-570 hydration and the hydration products of methanol accelerate the gelling process of colloidal silica. This also has some positive influences on the early strength enhancement. (C) 2016 Elsevier Ltd and Techna Group S.r.l. All rights reserved.