酸性条件下MSWI飞灰中Zn的浸出动力学

Leaching Kinetics of Zn in MSWI Fly Ash Under Acidic Condition

通过荧光光谱分析(XRF)、扫描电子显微镜(SEM)等测试方法并结合动力学模型理论研究了MSWI(垃圾焚烧)飞灰中典型重金属Zn在pH为4左右时的浸出过程,并在定温下探讨了该浸出过程的动力学模型.结果表明:该条件下MSWI飞灰中Zn的浸出过程适用于球体内扩散模型;扫描电镜下观测显示,大部分飞灰颗粒表面发生了不同程度的溶解,但在整个反应过程中都维持球状或高度类似球状的微观形貌,有力地支持了微观尺度的球体内扩散模型.重金属Zn的浸出率与时间的关系可描述为1-3(1-X)2/3+2X=18.25exp(-2 385.25T)/t.实验所得其浸出表观活化能约为19.831 kJ/mol.

Leaching process of typical heavy metal Zn in MSWI（ municipal solid waste incineration） fly ash when pH was controlled about 4 had been studied with the tests of EDS , XRF and SEM. Kinetic model for this leaching process was established through constant temperature method. The results showed that sphere controlled by internal diffusion model was appropriate for the leaching process of Zn. SEM tests revealed that most of MSWI fly ash particles maintained spherical or similar microstructure during the reaction though the surface of MSWI fly ash particles had dissolution at different level, which offered microscopic scales of evidence for sphere controlled by internal diffusion model. The relation between Zn leaching rate and reaction time（t） can be represent as 1 - 3 （ 1 - X）^ 2/3 ＋ 2X = 18.25exp（ - 2 385.25 T） / t with approximately 19. 831 kJ/mol apparent activation energy under experimental conditions.