Preparation of environmentally friendly low-cost mullite porous Ceramics and the effect of Waste Glass Powder on structure and mechanical Properties

Environmentally friendly low-cost porous ceramics are prepared with 98.2 wt% mining waste as the raw materials at 1180 degrees C. The glass powder forms liquid phase at high temperatures, promoting the densification of the materials. X-ray diffraction (XRD) results show that the formation of mullite is affected by sintering temperature and content of liquid phase. The enhancement in densification is verified by the scanning electron microscopy (SEM) analysis results. According to the evolution of pore structure, the effect of the glass powder on the structure is confirmed. The number ratio of pores of < 8 mu m to those of 8 similar to 20 mu m is varied from 7:2 to 2:7. The minimum apparent porosity is 31.22 %, while the maximum density and linear shrinkage are 1.75 g/cm(3) and 8.48 %, respectively. The flexural strength (three-point bending method) was increased from 7.47 MPa to 28.36 MPa, indicating that the addition of glass powder could increase mechanical properties of the porous ceramics. Therefore, solid wastes can be used as the resource to develop porous mullite ceramics.