CaO-MgO-Al2O3-SiO2 glass-ceramics from lithium porcelain clay tailings for new building materials

Lithium porcelain clay tailings (containing 1.2 wt.% Li2O) blended with other chemical raw materials were used to develop a new glass-ceramic of CaO-MgO-Al2O3-SiO2 system for rolling process. The effects of TiO2 and ZnO oxides on melting and crystallization behaviors of glasses were investigated by DTA, XRD, EPMA and viscosity test The results showed that melting temperature, forming temperature and glass transition temperature (T-g) of glasses were decreased with the increase of ZnO addition. Nevertheless, the crystallization temperature was shifted from 864 to 901 degrees C when the addition of TiO2 decreased from 2 wt.% to 0.5 wt.%. Diopside as a major crystalline phase and spinet as a minor phase are precipitated in M3 specimen with 2.5 wt.% ZnO and 0.5 wt.% TiO2. The columnar and granular crystalline phases were distributed in M3 specimen nucleated at 750 degrees C for 2 h and followed by crystallization at 1110 degrees C for 2 h, which resulted in proper appearance suitable for decorative materials. (C) 2014 Elsevier B.V. All rights reserved.