垃圾焚烧过程中氧化物对Cd和Zn迁移分布的影响

Effect of oxides on migration and distribution of Cd and Zn in waste incineration

采用管式炉模拟城市生活垃圾焚烧过程,考察了Al_(2)O_(3)、SiO_(2)和MgO在不同添加量以及不同温度下对重金属Cd和Zn迁移分布的影响,并利用HSC Chemistry热力学软件进一步模拟了焚烧过程中Cd和Zn的形态分布。实验结果表明:不同氧化物均能抑制Cd和Zn的挥发,且温度越低、氧化物的添加量越大,抑制效果越好;在不同温度下3种氧化物对Cd和Zn吸附效果的优劣顺序不同;在相同反应温度和相同氧化物添加量的条件下,3种氧化物抑制Zn挥发的效果均优于Cd。热力学模拟结果显示:Al_(2)O_(3)和SiO_(2)会与Cd和Zn反应生成各种不易挥发的金属化合物;而MgO可与体系中的Cl结合,抑制易挥发的重金属氯化物的生成。

The process of municipal solid waste incineration was simulated using a tube furnace.The effects of Al_(2)O_(3),SiO_(2) and MgO on themigration and distribution of Cd and Zn at different addition amounts and different temperatures were studied.The distribution of Cd and Zn in the process of waste incineration was simulated by HSC Chemistry software.The results indicate that:The 3 oxides can all inhibit the volatilization of Cd and Zn,and the lower the temperature and the larger the amount of oxide added,the better the inhibition effect;At different temperatures,the order of Cd and Zn adsorption effect on the 3 oxides was different;Under the conditions of same reaction temperature and same oxides amount,the inhibition effects of the 3 oxides on Zn volatilization are better than those on Cd volatilization.Thermodynamic simulation results show that:Al_(2)O_(3) and SiO_(2) will react with Cd and Zn to form various non-volatile metal compounds;while MgO can combine with Cl in the system to inhibit the formation of volatile heavy metal chlorides.