模拟酸雨环境下城市垃圾焚烧飞灰基地聚合固化体耐酸雨侵蚀能力研究

Research on MSWI-Geo based solidified body the ability of resistance to acid rain under simulated acid rain environment

为了探讨城市垃圾焚烧飞灰基地聚合固化体(以下称MSWI-Geo固化体)的长期耐久性,以抗压强度、氯离子渗透和重金属浸出浓度的变化为依据,探究n(CaO)/n(SiO_(2)+Al_(2)O_(3))对MSWI-Geo固化体性能影响。模拟酸雨环境对MSWI-Geo固化体进行侵蚀试验。结果表明:MSWI-Geo固化体的抗压强度随n(CaO)/n(SiO_(2)+Al_(2)O_(3))的增加,先增加后减小;当n(CaO)/n(SiO_(2)+Al_(2)O_(3))为0.95,碱掺量为15%时,MSWI-Geo固化体抗压强度最高,为22.36 MPa。随着n(CaO)/n(SiO_(2)+Al_(2)O_(3))达到0.95时,氯离子扩散系数下降最显著,达到5.42×10^(-9)m^(2)/s。通过MSWI-Geo固化体在模拟酸雨喷淋试验发现n(CaO)/n(SiO_(2)+Al_(2)O_(3))在0.9~1.0时,MSWI-Geo固化体在雨水和酸雨喷淋7 d后,强度损失率小于5%。SEM显示模拟酸雨腐蚀后固化体中出现CaSO4晶体。

The long-term durability of municipal solid waste incineration fly ash based solidified body(hereinafter referred to as MSWI-Geo solidified body),based on the changes of compressive strength,chloride ion penetration and heavy metal leaching concentration,the effect of n(CaO)/n(SiO_(2)+Al_(2)O_(3))on the performance of fly ash solidified body was studied.The erosion test of MSWI-Geo solidified body was carried out in simulated acid rain environment.The results show that the compressive strength of MSWI-Geo solidified body first increased and then decreased with the increase of n(CaO)/n(SiO_(2)+Al_(2)O_(3))molar ratio.When the ratio of n(CaO)/n(SiO_(2)+Al_(2)O_(3))was 0.95 and the alkali content was 15%,the compressive strength of MSWI-Geo solidified body is the highest,which was 22.36 MPa.When n(CaO)/n(SiO_(2)+Al_(2)O_(3))reached 0.95,the chloride ion diffusion coefficient decreased most significantly,reaching 5.42×10^(-9)m^(2)/s.Through the erosion test of MSWI-Geo solidified body,the strength loss under 7 d erosion of rain and acid rain immersion was less than 5%when n(CaO)/n(SiO_(2)+Al_(2)O_(3))is from 0.9 to 1.0.SEM shows that CaSO4 crystal appears in the solidified body after simulated acid rain corrosion.