关键词: As污染土壤, 烧结砖, 抗压强度, 环境安全性

Abstract: The factors affecting the sintering process of heavy metal contaminated soil and the environmental safety of sintering products are important issues for its resource utilization. Based on this, a simulation study on the resource utilization of sintered brick was carried out with As contaminated soil in Guangzhou(GZ), Changsha(CS), Suzhou(SZ) and Zibo(ZB) as raw material. The results indicated that the compressive strength of sintered bricks increased from 7.9% to 382.9% when sintering temperature increased from 900 ℃ to 950 ℃. The difference of soil mechanical composition leaded to significant difference in compressive strength of sintered bricks(P<0.01). The addition of 5%Na2CO3 and 5%Al2O3 could not only increase the compressive strength of the GZ soil sintered brick by 0.6 to 4.1 times, but also reduce the leaching concentration of As in the sintered brick by 88.4% to 98.8%, and the volatilization of As in the sintering process was reduced by 99.3%. Scanning Electron Microscope(SEM) and X-Ray Diffraction(XRD) results showed that the addition of compounds such as Na2CO3 and Al2O3 during sintering could lead to soil mineral changes, and could play multiple roles in filling, sealing and wrapping the lamellae gaps generated during sintering, thus significantly reduced the leaching concentration and volatilization of As.

Key words: As contaminated soil, sintered bricks, compressive strength, environmental safety