Abstract:

Waste incineration slag is considered as a kind of dangerous solid waste，harmless utilization of waste incineration slag is of great significance.In this study，permeable brick with satisfactory comprehensive performances was prepared by high-temperature sintering process using waste incineration slag as raw material，and the effects of waste incineration slag addition and firing temperature on the properties of samples were explored.The results showed that the strength and safety of the samples could be improved by introducing suitable amount of waste glass and properly increasing sintering temperature.When the amounts of waste incineration slag，waste glass and pulverized coal（additional） were 60%，40%，and 20% respectively，the water permeability coefficient，flexural strength and compressive strength of permeable brick fired at 1 200 ℃ reached 0.58 mm/s，6.23 MPa and 18.58 MPa，respectively.The flexural strength and permeability coefficient had respectively reached the R_f4.5 and B levels，meanwhile，the leaching concentration of Cu²⁺，Pb³⁺ and Zn²⁺ in the product met the GB 5085.3—2007《Identification standard for hazardous waste leaching toxicity identification》standard.The XRD and SEM-EDS analysis results showed that the high-temperature liquid phase derived from melting waste glass dissolved Pb₂O₃，ZnO and CuO，thus inhibiting the leaching of Cu²⁺，Pb³⁺ and Zn²⁺.It was also found that raising the firing temperature reduced the porosity of the sample and promoted the dissolution of lead oxide，zinc oxide，and copper oxide，thereby synergistically improving the environmental safety of the product.Additionally，it was concluded that the high strength and excellent water permeability of the permeable brick was resulted from the mutual cementation of mullite and glass as well as even distribution of connecting pores.

Key words: waste incineration slag, permeable brick, water permeability, compressive strength, leaching concentration