Hydrothermal synthesis of xonotlite-type calcium silicate insulation material using industrial zirconium waste residue

Xonotlite-type insulation material was prepared by hydrothermal synthesis technology using industrial zirconium waste residue in this paper, and the phase analysis together with the observation of micro-morphology were also carried out by XRD, SEM and TEM. The density and thermal conductivity were measured finally. The results indicate, chlorine ion impurity contained in zirconium waste residue can be removed effectively via water washed process, and the reactive activity of silicon dioxide is almost not affected, which make it be a good substitution of silicon material for the preparation of calcium silicate insulation material by hydrothermal synthesis technique. The density and thermal conductivity of xonotlite-type calcium silicate insulation material obtained by hydrothermal synthesis technique can reach 159 kg/m³, 0.049 W/(m·° C), respectively, meeting with National Standard well, when synthesis conditions are selected as follows: Ca/Si molar ratio equal to 1, synthesis temperature at 210 °C and kept for 8 hrs. It provides a new approach to realize lightweight and low thermal conductivity of calcium silicate insulation material.