Effect of SiC on Pore Structure and Physical Properties of Porous Glass-ceramics Derived from Surface Modified Pickling Copper Mine Tailings

Porous glass-ceramics were derived from surface-modified pickling copper mine tailing powder with boehmite sol(1 wt.%) as the sintering additive and SiC (0-5.0 wt.%) as the foaming agent. The effect of SiC on pore structure, compressive strength and thermal conductivity of the glass-ceramics were systematically studied. With increasing content of SiC, the pores generated by the blowing agent in the porous glass-ceramics gradually connected and coalesced with the residual pores in the matrix to form larger pores. The porosity first increased and then decreased, the compressive strength and specific strength continued to decrease, and the thermal conductivity first decreased and then increased. With 2.0 wt.% SiC, the porosity of porous glass-ceramics is 45.6%, while the compressive strength and thermal conductivity are 60.4 MPa and 0.828 W·m^-1·K^-1, respectively. The theoretical value of thermal conductivity is higher than the measured value at low porosity, while the theoretical value is basically the same as the measured value at high porosity, indicating that the pores are of closed structure after coalescence. These red porous glass-ceramics are suitable for lightweight decorative building materials, thus realizing the value-added utilization of copper mine tailings.