Preparation of low cost glass-ceramics from molten blast furnace slag

In the current paper, a low-cost technology was used to prepare glass ceramics through directly heat-treating with molten glass containing blast furnace slag and silica sand. By making use of the sensible heat of the molten slag, the energy cost was much lower than that in conventional method. The utilized ratio of slag was about 90% and the optimum heat treatment schedule for glass ceramics was confirmed by an L-9(3(4)) orthogonal test. The effect of CaF2 on the microstructure of the glass ceramics was studied by DSC, XRD and SEM, the bending strength of the glass ceramics was tested by three points bending tester. The results showed that, after the optimum heat treatment schedule of nucleation at 780 degrees C for 0.5 h and crystallization at 960 degrees C for 1.5 h, the crystalline phases were akermanite and diopside, the bending strength of the glass-ceramics was about 45.8 MPa. If CaF2 was added, a remarkable reduction of crystal size was observed, the crystallization of diopside and Ca2SiO2F2 was promoted while that of akermanite was inhibited, the bending strength of glass ceramics samples could be greatly improved to 120 MPa. (C) 2011 Elsevier Ltd and Techna Group S.r.l. All rights reserved.