Preparation of foam glass ceramics from hazardous waste vitrification slag with the addition of Na₂CO₃

Hazardous waste vitrification has been recognized as an effective method for waste treatment, but there is still a need to explore the utilization of its vitrification slag. The feasibility of preparing foam glass ceramics from hazardous waste vitrification slag was verified in this study based on the thermodynamics analysis and the experimental exploration of the effect of the Na2CO3 addition on the transformation of hazardous waste vitrification slag (HWVS) during the roasting process. Thermodynamic calculations and TG-DSC analysis results inferred that the suitable theoretical roasting temperature for preparing foam glass ceramics from the HWVS/ Na2CO3 should be 900(degrees)C-1000(degrees)C. The experimental results demonstrated that a good foam glass ceramics with bulk density of 0.50 g/cm(3), compressive strength of 1.93 MPa, apparent porosity of 74.10%, and water absorption ratio of 0.30% can be obtained by roasting HWVS with 4 wt% Na2CO3 and 2 wt% trisodium phosphate at 950(degrees)C for 1 h. During the preparation process of foam glass ceramics, the thermal decomposition of Na2CO3 generated a large number of bubbles, achieving foaming and expansion. Additionally, the appropriate content of the liquid phase generated during roasting acted as a consolidating agent during cooling, enhancing the strength of foam glass ceramics. These findings provide valuable insights for the resource utilization of vitrification slag.